Cellular and Molecular Biology Journal
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Acute and chronic estrogen supplementation decreases uterine sympathetic innervation in ovariectomized adult virgin rats
Uterine innervation undergoes substantial reorganization associated with changes in reproductive status. Nerves innervating the uterus are decreased in U pregnancy and puberty, and even the normal rodent estrous cycle is characterized by fluctuations in numbers of myometrial nerve fibers. During the follicular (proestrus/estrous) phase of the estrous cycle, intact nerves are rapidly depleted and then return over the next 2-3 days in the luteal (metestrus/diestrus) phase. We hypothesize that uterine nerve depletion is initiated by increased circulating estrogen in the follicular phase. However. studies have not shown whether estro"ge n can reduce uterine innervation and, if so, whether the time course is compatible with the rapid changes observed in the estrous cycle. These questions were addressed in the present study. Mature ovariectomized virgin rats received 17-B-estradiol as a single injection (10 pg/kg s.c.) or chronically from timed-release pellets (0.1 pglpellet for 3 weeks sustained release). Total (protein gene-product 9.5-immunoreactive) and sympathetic (dopamine B-hydroxylase-immunoreactive) uterine innervation was assessed quantitatively. Both total and sympathetic innervation was abundant in uterine longitudinal smooth muscle of ovariectomized rats. However, following acute or chronic estrogen administration, total and sympathetic fiber numbers were markedly decreased. This was not due to altered uterine size, as reductions persisted after correcting for size differences. Our results indicate that sympathetic nerves are lost from uterine smooth muscle after estradiol treatment in a manner similar to that seen in the intact animal during estrus and pregnancy. This suggests that the rise in estradiol prior to estrus is sufficient to deplete uterine sympathetic innervation.
Comparison of NADPH diaphorase activity in the brains of hamsters infected with scrapie strains 139H or 263K or with normal hamster brain homogenate
Previous studies showed that the histopathological changes found in the brains of scrapieinfected animals included amyloid plaque formation, vacuolation, gliosis and neuronal and neurite degeneration. There were differences in the histopathological findings as a function of the scrapie strain-host combination. NADPH-diaphorase (NADPHd) has been shown to be a selective histochemical marker for neurons containing nitric oxide (NO) synthase. Neuronal cell damage caused by NOS in brain has been reported to be associated with many neurodegenerative diseases. In this study, we used NADPH-d histostaining to investigate changes in the NOS system in brains of 139H- and 263K-infected hamsters and compared the results to normal hamster brain (NHB) injected animals. We observed that some of the NADPH-d histostaining neurons in the cortex of scrapie-infected hamsters appeared to be atrophic: the neurons were smaller and had fewer neurites. The NADPH-d histostaining intensity of neurons or astrocytes in septum, thalamus, hypothalamus and amygdala of 139H- and 263K-infected hamsters was greater than in control hamsters. Astrocytes in the thalamus, hypothalamus and lower part of the cortex (layers 4 to 6) in 263K-infected hamsters were more intensely stained for NADPH-d than in either 139Hinfected hamsters or controls. Our results suggest that changes in NADPH-d system might play a role in the diversity of scrapie induced neurodegenerative changes.
lmmunohistochemical expression of p53, p2l/wafl, Rb, p16, cyclin D1, p27, Ki67, cyclin A, cyclin 61, bc12, bax and bak proteins and apoptotic index in normal thymus
The immunohistochemical expression of p53, p21, Rb, p16, cyclin D1, Ki67, cyclin A, cyclin B1, p27, bc12, bax, and bak proteins and the apoptotic index (AI) were investigated in 20 normal thymuses (8 adults, 3 adolescents, 5 infants and 4 newborns). The expressions of Rb, Ki67, cyclin A and cyclin B1 were overlapping, being high in the cortex with a tendency for decreased expression toward the medulla. Apoptotic cells were mainly detected in the cortex and the corticomedullary junction, rarely being present in Hassall's corpuscles. The mean values of Ki67, cyclin A, and cyclin B1 expression in thymuses were 77.2%, 32.2% and 21.4% (newborns), 62.4%, 33.7% and 18.5% (infants), 56.9%, 23.4% and 18.9% (adolescents) and 38.7%, 21.7% and 14.6% (adults), respectively. The mean values of AI in thymuses from newborns, infants, adolescents and adults were 1.4%, 2.9%, 2.7% and 3.8%, respectively. This decrease in proliferation and increase in apoptosis may account for the process of thymic involution. P16 expression was widespread with most of Hassall's corpuscles being pl6-positive. P16- positive cells and Hassall's corpuscles increased with the increase in age, in keeping with the suggested role of p16 in cellular senescence. P27 expression was undetectable in subcapsular thymocytes with a tendency for increased expression toward the medulla. The expressions of Ki67, cyclin A and cyclin R1 were inversly related with that of p27, consistent with previous evidence that p27 concentration is reduced when the cell-cycle progresses. P21 and much less frequently p53 proteins were mainly detected in a part of the subcapsular cortical epithelial cells. These findings suggest that a) in thymocytes, the apoptotic pathway is mostly p53-independent and the function of p21 as a negative regulator of the cell cycle must be redundant to other negative regulators, such as p16 and p27 which were abundantly detected in thymocytes and b) in some thymic epithelial cells, the p21 expression may be induced by p53, but in most of them seems to be p53- independent. Most of Hassall's corpuscles were p21- positive, consistent with previous evidence that these structures represent end stages of maturation of thymic medullary epithelium and that p21 protein is involved in the process of terminal differentiation. Cyclin D1 positivity was found in some macrophages. Rc12 expression was mainly seen in medullary thymocytes, reflecting the surviving thymocytes in this region. The expressions of Bax and bak were more widespread in both the medulla and cortex, suggesting that these proteins play a broader role than bc12 in the regulation of thymic apoptosis.
Transcriptional mRNA of BMP-2,3, 4 and 5 in trigeminal nerve, benign and malignant peripheral nerve sheath tumors
The aim of our study was to document whether relationships existed among bone morphogenetic proteins (BMPs), peripheral nerve and neoplastic lesions of nerve sheath tumors. The mRNA transcriptions of BMP-2, 3, 4 and 5 in 10 cases of schwannoma, three cases of malignant schwannoma and two cases of trigeminal neuralgia were detected using an in situ hybridization technique. Our results demonstrated that the myelin sheaths of Schwann cell from the peripheral neuroectomy of trigeminal neuralgia positively expressed mRNA of BMP-2, 3, 4, and 5. The most interesting finding was that the nerve fibers of trigeminal nerve showed only BMP-2 positive staining. All of the neoplastic lesions of nerve sheath showed a consistent but variant expression of BMP-2, 3, 4, and 5. The expression signals of BMP-2, 3, 5 mRNA in malignant schwannoma were relatively lower than in benign lesions except for the expression of BMP-4 mRNA. Our results indicated that selected members of BMPs were expressed in the peripheral nerves that might contribute to the health maintenance, proliferation, regeneration and neoplastic transformation of the peripheral nerve system. Furthermore, the effects of BMP-2, 3, 4 and 5 on peripheral nervous system during neoplastic transformation might be widespread, diverse and antagonistic.
Differential expression of laminin isoform (α2), integrins (α3β1 and α6β4) and cytokeratin 20 in H. pylori gastritis
The expression of laminin-l chains (131 and yl), laminin-2 (merosin), integrin receptors to laminin (α3β1 and α6β4) and cytokeratin (CK20) were studied by immunohistochemical methods in gastric biopsies from antrum of 25 patients. H. pylori gastritis was found in 19 cases and intestinal metaplasia (IM) in four from these 19. Another 13 biopsies, all with IM were immunostained to laminin-2. Laminin-l chains in normal and gastritis areas without 1M were expressed as a strong, linear and continuous deposit in the basement membranes of the superficial and glandular epithelium. In metaplastic glands the reactivity to laminin-l chains was decreased. Merosin was discontinuous when a moderate to accentuated H. pylori glandular colonization was present. Samples with IM were negative to laminin- 2. The α3β1 and α6β4 integrins were negative only in IM gastric biopsies. The CK20 immunoreactivity was strong and homogeneous in the cells at the tip and the upper portion of foveolae in normal areas and in gastritis with IM the reactivity to CK 20 was heterogeneous. A differential expression of laminin isoforms is related to inflammation and subsequent IM caused by H, pylori. The alterations of α3β1 and α6β4 parallel both modifications in merosin and CK20 expression in H. py10r.i chronic gastritis.
Thrornbomodulin, calretinin and c-kit (CD1 17) expression in cardiac myxoma
The immunohistochemical profile of cardiac myxoma has been debated. The tumor is thought to be derived from multipotential undifferentiated mesenchymal cells. A consistent marker for this tumor has not been found. In this article an immunohistochemical study of 23 cardiac myxomas was accomplished. This study comprised the immunoreactivity of the tumors for thrombomodulin, calretinin and and c-kit (CD117). To the best of our knowledge, thrombomodulin and c-kit have not been tested in cardiac myxoma. Calretinin expression has been recently demonstrated in cardiac myxoma, although this finding has not been yet validated. Surface lining cells, tumor vascular endothelium, cells around the vascular slits and stromal cells embedded in the myxoid matrix were assessed independently. All tumors showed reactivity for thrombomodulin in the s u r f a c e c e l l s and in the endothelium of neoplastic vessels. 82.6% of cardiac myxomas expressed thrombomodulin in the stromal cells and 69.6% of the tumors were reactive in the perivascular cells. 73.9% of cardiac myxomas expressed calretinin in the stromal cells and in the perivascular cells. All myxomas were negative f o r c-kit. Thrombomodulin and calretinin may be important diagnostic aids for cardiac myxoma. Cardiac myxoma cells do not express embryoniclfetal endothelial antigens.
Expression of integrin αvβ3 in pig, dog and cattle
The αvβ3 integrin, also known as vitronectin receptor, is an adhesive glycoprotein that promotes angiogenesis i n the embryo and tumors such as melanoma. Integrin αvβ3 is one of the receptors for adenovirus and hantavirus. There is little information on the constitutive expression of this integrin especially in animal species that are used for biomedical research. We used light and electron microscope immunocytochemistry and western blots to determine integrin avβ3 expression in seven organs in the pig, dog and cattle. Immunohistology showed the integrin expression on the epithelium of small intestine, bile duct and renal proximal convoluted tubules in three species. The airway epithelium revealed a weak reaction for integrin αvβ3. Skin showed the integrin in occasional extravascular cells while skeletal muscles were negative. The integrin was expressed only in bronchial vasculature in the lung and occasional dermal microvessels. Many mononuclear cells in the lung and spleen stained for integrin αvβ3. Immunogold electron microscopy revealed the expression on the epithelium but not on the vasculature of the small intestine. Western blots detected integrin αvβ3 in small intestine and lung but not in skeletal muscles. We conclude the integrin is expressed on the epithelium but not in the vasculature. The expression differs strikingly among organs in the same species although the inter-species differences are minor. Restriction of the integrin to absorptive epithelia of small intestine and kidney may suggest its putative role in endocytosis. Because the integrin is a receptor for adenovirus, these data may be relevant to gene therapy studies.
Cytochemical study of the involvement of cell organelles in formation and accumulation of fibrillar amyloid in the pancreas of NORβ transgenic mice
Phosphatase ultrastructural cytochemistry was used to evaluate the participation of cytoplasmic organelles in the accumulation of fibrillar amyloid β (Aβ) in exocrine acinar cells and in macrophages of the pancreas of transgenic mice overexpressing a carboxyterminal fragment of Aβ protein precursor (AβPP). Nucleoside diphosphatase (NDPase) and glucose-6- phosphatase (G6Pase) were used as cytochemical markers of the endoplasmic reticulum (ER), thiamine pyrophosphatase (TPPase) as a marker of the Golgi apparatus (CA), and acid phosphatase (AcPase) as a marker of lysosomes. Monoclonal antibody 4G8 raised against the 17-24 aa sequence of human Aβ protein was used for immunogold localization of fibrillar Aβ. The results of this study indicate that the formation of Aβ in acinar cells occurs directly in the vacuolar areas of the rough ER (RER) without evident participation of the elements of the GA, whereas an intimate structural relation with primary lysosomes suggests their role in modification or digestion of the deposited amyloid. In macrophages, fibrillar amyloid was present in numerous cytoplasmic vacuoles located frequently in close proximity to flattened saccules of the ER. This structural pattern revealed similarity to that observed previously in microglial cells producing fibrillar PrP amyloid in scrapie-infected mice and Aβ in brains of human elderly patients and in Alzheimer's type brain pathology.
Expression of the retinoblastoma-related p107 and Rb2/p130 genes in human placenta: an immunohistochemicaI study
It has been proposed that tumor suppressor genes may have a role in the mechanisms of proliferation and differentiation during human placental development. The Retinoblastoma gene family is a well known family of tumor suppressor genes. Many studies have pointed out a role of this family not only in cell cycle progression, but also during development and differentiation. On the light of these observations we have investigated the immunohistochemical expression pattern of the Retinoblastoma family members, p107 and Rb2/p130 in human placenta samples in first trimester and full-term placental sections. p107 and pRb2lp130 showed the most abundant expression levels during the first trimester of gestation and progressively declined to being barely detectable in the placenta by late gestation. These results indicate that the expression of the above genes is modulated during placental development and suggest a mechanism for controlling trophoblast proliferation.
Vascular endothelial growth factor (VEGF), transforming growth factor-β (TGFβ), and interleukin-6 (IL-6) in experimental herpesvirus retinopathy: association with inflammation and viral infection
Experimental herpesvirus retinopathy presents a unique model of a transient inflammatory response in the virus-injected eye and subsequent acute retinal necrosis and chronic inflammation in the contralateral eye. For 6 days after infection, VEGF, TGFβ, and TGFβ2 were associated only with inflammatory cells in the injected eye. By 6 days (after viral antigens were no longer detected), VEGF and TGFβ2 were upregulated in retinas of injected eyes until 8-10 days. In contralateral eyes, VEGF was first demonstrated in the retina at 6-7 days (prior to the appearance of viral antigens) and TGFβ2 at 7-8 days. Staining for these factors was also evident around areas of necrosis. The VEGF receptor, flt- l, was associated with ganglion cells and the inner nuclear layer of normal and experimental mice and it was also demonstrated around areas of necrosis. Another VEGF receptor, flk-l, was localized to Miiller cell processes and the outer plexiform layer in normal and experimental mice. Coincident with VEGF upregulation in the retinas of herpesvirus-l injected mice, there was increased flk-l in ganglion cells and the inner and outer nuclear layers. IL- 6 was associated with Miiller cell endfeet in normal mice. Following unilateral intraocular inoculation, 1L-6 spread along the Miiller cell processes and some astrocytes demonstrated IL-6 in both eyes at 6-8 days. The present study demonstrates that intraocular inoculation of herpesvirus is sufficient to induce VEGF, flk-l, TGFβ2, and IL-6 in the retinas of injected and contralateral eyes. Further investigation of common signaling pathways for these factors during responses to viral infection and the development of acute retinal necrosis could provide information useful for therapeutic intervention in human herpesvirus retinopathy.
Synthesis of calcitonin gene-related peptide (CGRP) by rat arterial endothelial cells
We investigated the protein and mRNA expression of calcitonin gene-related peptide (CGRP) in endothelial cells of the rat thoracic aorta and femoral artery. Light microscopic immunocytochemistry revealed that immunoreactivity for CGRP was preferentially located in the endothelium of both vessels. Immunoelectron microscopy showed that CGRPimmunoreactive gold particles were preferentially localized on cisterns of the rough endoplasmic reticulum and on the Weibel-Palade (WP) bodies in the endothelial cells. Prepro CGRP mRNA signals were also detected on the endothelium. Our results are the first to demonstrate that endothelial cells of both elastic and large muscular arteries synthesize CGRP and store it, in part, in WP bodies, implying that CGRP may act as an endothelium-derived relaxing factor in these vessels.
CO-localization of integrins and matrix metalloproteinases in the extracellular matrix of chondrocyte cultures
β1-integrins were found in the cartilage matrix, suggesting their implication in the assembly of its architectural scaffold, but the mechanism for this event is not yet clear. Matrix metalloproteinases (MMPs) may be involved in an integrin-shedding mechanism and matrix β1- integrins may act to alter MMP activity. To begin to address this question, this study was designed to determine whether β1-integrins and MMPs are colocalized in the chondrocytes or in the extracellular matrix of cartilage. We investigated high-density cultures of limb buds of 12-day-old mouse embryos by double immunofluorescence, immunoelectron microscopy and by coimmunoprecipitation assays in order to examine the localization of β1-integrins and matrix metalloproteinases (MMP-1, MMP-3 and MMP-9) in cartilage. It was found, that all investigated MMPs and β1- integrins were specifically CO-localized in high-density cartilage cultures. Immunogold and immunofluorescence labelling of both β1-integrins and MMPs were observed not only at the surface of chondrocytes but mainly also in the pericellular space and distributed between collagen fibrils in the extracellular matrix (ECM) as well. Results of immunoprecipitation experiments suggest a functional association of MMPs and β1- integrins in chondrocytes as already described for other cell types. Further investigations are needed to elucidate the functional association between β1-integrins and MMPs in chondrocytes.
Comparative study of the acute toxicity of anionic surfactans alkyl benzene sulphonate (ABS) and sodium dodecyl sulphate (SDS) on gilthead, Sparus aurata L., eggs
In the present work we have evaluated the acute toxicity of two anionic surfactants, alkyl benzene sulphonate (ABS) and sodium dodecyl sulphate (SDS) to eggs of gilthead Sparus aurata. At each surfactant concentration, we determined the exposure time required for 50% mortality of the eggs (LT50), surface tension and volume of oil globule in gilthead eggs. Clear dose-response relationships for mortality of gilthead eggs was observed for both toxicants; at 30 mg/L 50% mortality took place at 45 minutes for ABS and 8 minutes for SDS. At this concentration, SDS was almost six times more toxic than ABS (LT50 is compared). However, at 0.3 mg/L 50% mortality occurred after exposures of 535 minutes to ABS and 425 minutes to SDS. Descriptively, our results showed SDS was more toxic than ABS at high concentrations whereas at low concentrations their toxicity was very similar. However, statistical analysis demonstrated there were no significant differences in the toxicity of both surfactants to gilthead eggs. Surface tension value at each concentration of both surfactants was also calculated. We found that these values decreased with increasing concentration of each surfactant, and this trend was more pronounced in solutions of SDS. We also found that the volume of the oil globule of exposed eggs was influenced by surfactants. After exposure, its volume clearly decreased in comparison to controls, mainly in eggs exposed to SDS.
Alterations induced by E-cadherin and β-catenin antibodies during the development of Bufo arenarum (Anura-Bufonidae)
E(epithelia1)-cadherin is a member of a calcium-dependent family of cell surface glycoproteins involved in cell-cell adhesion and morphogenesis. Catenins are a large family of proteins that connect the cadherins to the cytoskeleton. They are important for cadherin function and for transducing signals involved in specification of cell fate during embryogenesis. The best characterized catenins include α-, β-, ɣ-, and p120- catenin. Using specific antibodies, we studied the expression and distribution of E-cadherin, and a- and β-catenin in developmental stages of Bufo arenarum toad. The three proteins were found CO-localized in stages 19 to 41 of development. Surprisingly, E-cadherin was the only of these three proteins found earlier than stage 19. To test whether E-cadherin and β-catenin have a functional role in Bufo arenarum embryogenesis, stage 17 whole embryos were incubated with anti-E-cadherin and β-catenin antibodies. Both anti-E-cadherin and anti- β-catenin antibodies induced severe morphological alterations. However, while alterations produced by the anti-β-catenin antibody, showed some variability from the most severe (neural tube and notochord duplication) to a simple delay in development, the alterations with anti-E-cadherin were homogeneous. These observations suggest a critical role for E-cadherin and β-catenin in the early embryonic development of the Bufo arenarum toad. Our results are consistent with the developmental role of these proteins in other species. One of the most surprising findings was the blockage with the anti-β-catenin antibodies on later embryo stages, and we hypothesize that the partial axes duplication could be mediated by the notochord induction.
Characterization of GFAP expression and cell proliferation in the rat median eminence following hypophysectomy
To analyze whether the reorganization of the rat median eminence after hypophysectomy might be related to changes in glial fibrillary acidic protein (GFAP)- and cellular proliferation, the distribution of cells immunoreactive for GFAP and the proliferation rate of such cells were analyzed at 20, 40 and 60 days posthypophysectomy. For this study, four rostro-caudal regions of the median eminence were differentiated: the retrochiasmatic, preinfundibular, infundibular and postinfundibular regions. In each of these regions, three layers were studied: the ependymal, the internal and the external. At 20 and 40 days after hypophysectomy, significant increases in cellular proliferation affecting all three layers studied in the preinfundibular and infundibular regions were found. At the same time points, increases in GFAP expression were also observed. However, after 60 days, GFAP and proliferative cellular nuclear antigen (PCNA) expression decreased. Although variations of PCNA and GFAP levels were evident, no colocalisation of PCNA and GFAP was found in the cells of the median eminence in untreated or hypophysectomized rats when sections were analyzed by double immunohistochemical staining. Our results suggest that reorganization of median eminence involves alterations (or modulation) of GFAPimmunoreactive cells together with a proliferation of cells that are not GFAP-immunoreactive. This study also demonstrates that this reorganization is completed within the first two months after hypophysectomy.
Consecutive light microscopy, scanning-transmission electron microscopy and transmission electron microscopy of traumatic human brain oedema and ischaemic brain damage
Cortical biopsies of 11 patients with traumatic brain oedema were consecutively studied by light microscopy (LM) using thick plastic sections, scanning-transmission electron microscopy ((S)TEM) using semithin plastic sections and transmission electron microscopy (TEM) using ultrathin sections. Samples were glutaraldehyde-osmium fixed and embedded in Araldite or Epon. Thick sections were stained with toluidine-blue for light microscopy. Semithin sections were examined unstained and uncoated for (S)TEM. Ultrathin sections were stained with uranyl and lead. Perivascular haemorrhages and perivascular extravasation of proteinaceous oedema fluid were observed in both moderate and severe oedema. Ischaemic pyramidal and non-pyramidal nerve cells appeared shrunken, electron dense and with enlargement of intracytoplasmic membrane compartment. Notably swollen astrocytes were observed in all samples examined. Glycogen-rich and glycogen-depleted astrocytes were identified in anoxic-ischaemic regions. Dark and hydropic satellite, interfascicular and perivascular oligodendrocytes were also found. The status spongiosus of severely oedematous brain parenchyma observed by LM and (S)TEM was correlated with the enlarged extracellular space and disrupted neuropil observed by TEM. The (S)TEM is recommended as a suitable technique for studying pathological processes in the central nervous system and as an informative adjunct to LM and TEM.
TGF-β1 and IL-6 expression in rat pineal gland is regulated by norepinephrine and interleukin-1β
The pineal gland is part of the neuroendocrine system that modulates immune functions. Because the gland is outside the blood-brain barrier, i t is accessible to direct feedback from circulating cytokines that affect the synthesis and secretion of melatonin. Recent studies have suggested lhat intrinsic immunoregulatory cytokines mediate these neuro-immune interactions under the control of sympathetic innervation to the pineal. This study focused on the expression of transforming growth factor-β1 (TGF-β1) and interleukin-6 (IL-6), two cytokines that have important regulatory functions on both neurons and immune cells. Northern blot RNA analysis showed that TGF-β1, but not IL-6, was expressed in freshly dissected rat pineal glands from neonatal age (l-day-old) into adults. Immunocytochemistry for TGF-β1 in adult glands revealed localization of this protein in astrocytelike cells. The sympathetic neurotransmitter norepinephrine (NE) increased transcript levels for both TGF-β1 and IL-6 in adult pineal organ cultures. The effect of NE on IL-6 expression was not found in dispersed cell cultures established from neonatal pineal glands. The immunoregulatory molecule interleukin-1β (IL-113) up-regulated the expression of both IL-6 and TGF-β1 in adult pineal organ cultures, but not in neonate pineal organ cultures. These findings suggest that TGF-β1 and IL-6 have intrinsic regulatory roles in the pineal gland and that both neural and immune factors are important mechanisms of regulation.
Vestibular histofluorescence could be due to accumulation of both the antibiotic and its derivative, streptidine, after acute streptomycin treatment in the guinea pig
Acute treatment with 300 mglkg of pigmented guinea pigs with streptomycin sulfate induces an elevation of endogenous fluorescence in vestibular ampullary cristae. Fluorescence accumulates in all compartments of the epithelium, i.e., vestibular sensory and supporting cells and nerve fibers of the stroma and it was very intense 1 and 12 hours after its administration. Fli~orescence decreased to control levels 24 hours following streptomycin injection. Fluorescence levels were very low either in untreated animals or in animals injected with s a l i n e physiological solution. To investigate whether this fluorescence was an intrinsic property of the antibiotic or whether it was due to a derivative of it, or both, an in vitro fluorescence spectrum was performed with 100 μM solutions of streptomycin or streptidine, or both, dissolved in various buffer solutions at 488 nm of excitation. A discrete level of fluorescence was observed in the spectrum regardless of media when separate solutions of both streptomycin or streptidine were studie d . Fluorescence notably increased at 522-532 nm when the solutions contained both streptomycin and streptidine toget her. These results suggest that streptidine putatively derived from streptomycin may contribute to the observed fluorescence accumulation in vestibular preparations after acute treatment. Thus, these metabolic properties of the inner ear which transform streptomycin into streptidine, something never considered earlier, could be claimed as partially responsible for converting a therapeutic agent into a compound which could be as harmful as STP to the inner ear.
Analysis of the in vivo dendritic cell response to the bacterial superantigen staphylococcal enterotoxin B in the mouse spleen
To investigate the in vivo effects of Staphylococcal enterotoxin B (SEB) on dendritic cells (DCs) in the spleen, a single dose of SEB (50 μg/kg) was administered to BALBIc mice by intraperitoneal injection. Afterwards, the mice were sacrificed at 2, 6 and 24 hr, 2, 4, 7 and 15 days, and the spleens were removed. The immunocytochemical characterization of the cells was carried out using various monoclonal antibodies in cryostat-cut sections. The distribution patterns of DCs and their major costimulatory molecules, CD80, CD86 and CD40 in the spleen were identified, and the evidence for maturation of DCs in vivo in response to SEB was obtained. I t was found that systemic administration of SEB induced the migration of most of the immature, splenic DCs from the marginal zone to the periarterial lymphatic sheath within 6 hr. This movement paralleled a maturation process, as assessed by upregulation of CD40, CD80 and CD86 expression in the interdigitating dendritic cells (IDCs). The upregulation of costimulatory molecule expression was conspicuous only in DCs in contrast to other antigen-presenting cells (APCs) such as macrophages and B cells which did not show any significant alterations in their costimulatory molecule expression. We also demonstrated the temporal expression pattern of these costimulatory molecules on the activated DCs. The upregulation of costimulatory molecules on DCs reached a peak level 6 hr after SEB injection, while the increase in number of T cells expressing T cell receptor V88 reached a peak level on day 2 after SEB treatment. In conclusion, we demonstrated the in vivo DC response to SEB in the mouse spleen, especially a potent stimulative effect of SEB on DCs in vivo, a temporal distribution pattern of DCs as well as T cells including TCR Vβ8+ T cells, and a differential expression pattern of costimulatory molecules on the activated DCs. The results of the present study indicate that DCs are the principal type of APCs which mediate T cell activation by SAg in vivo, and that each costimulatory molecule may have different role in the activation of DCs by SAg. Thus, it is plausible to speculate that DCs play a critical role in the T cell clonal expansion by SAgs and other SAg-induced immune responses in vivo.
Electron microscopic studies of ion- and H20-transporting epithelial cells in the horizontal ampulla of the pigeon
Earlier morphological studies of the epithelial structure in the semicircular canals of mammals have focused on the sensory cells of the crista ampullaris. This report draws attention to the fact that there exist at least seven further cell types in the horizontal ampulla walls of pigeon with various functions; the role of ion- and H20-transporting epithelial cells is dealt with here in detail. While the dark cells appear to play a decisive role in the regulation of ionic composition, the cells in the planum semilunatum may transport H20 and assist in the regulation of endolymph volume. In addition, protein-secreting structures are located in the apical region of the cells of the planum semilunatum. The question whether the proteins are dispersed in the endolymph or contribute to cupula formation remains unclear. The morphology and possible functions of these two cell types are discussed on the basis of electron microscopic results.
Arterial wall neovascularization induced by glycerol
An intense and significant neovascularization, with numerous capillaries growing into the media layer of the rat femoral artery, was demonstrated when glycerol was administered into the interstitium between the femoral vein and the femoral artery. The maximum microvascularization was observed at days 7 and 9 after glycerol administration. Afterwards, involution of the majority of the newlyformed microvessels in the arterial wall occurred. Other substances containing glycerol in their molecules, such as triacetyl-glycerol and tributyril-glycerol, failed to produce significant neovascularization in the media layer of the femoral artery. Neovascularization of the arterial wall was preceded by a considerable decrease in the number of the smooth muscle cells, which experienced apoptosis and necrobiosis, disappearing in extense areas of the arterial segment affected by glycerol. Coinciding with neovascularization and microvascular involution, repopulation of the media layer by smooth muscle cells was observed.
Tight junctions and their role in cancer metastasis
Tight Junctions govern the permeability of endothelial and epithelial cells and are the most topical structures of these cell types. Tight junctions create an intercellular barrier and intramembrane diffusion fence. An important step in the formation of cancer metastases is interaction and penetration of the vascular endothelium by dissociated cancer cells. Early studies demonstrated a correlation between the reduction of tight junctions and tumour differentiation and experimental evidence has emerged to place tight junctions in the frontline as the structure that cancer cells must overcome in order to metastasise. Changes in tight junction function are thus an early and key aspect in cancer metastasis. Further work is required to fully realise the potential that this structure has in cancer invasion and metastasis in order to develop new and novel therapies in the prevention of tumour metastasis.
Cytochemical localization of Na+/K+-ATPase activity in cochlear strial marginal cells after various catecholamine administrations
Sodium/potassium-activated adenosine triphosphatase (Na+/K+-ATPase) activity in the kidney and brain is high, and is regulated by catecholamines. Na+/K+-ATPase activity is also high in the basolateral infoldings of the strial marginal cells, where it aids in maintaining the characteristic electrolyte composition of the endolymph. To clarify the involvement of humoral control in strial function, particularly the role of catecholamines, the K+-dependent p-nitrophenylphosphatase (K+-NPPase) activity of strial marginal cells was investigated in guinea pigs using a ceriumbased cytochemical method. The effects of reserpine, serotonin (5-HT), norepinephrine (NE), epinephrine (EP), both alone and in combination, were studied. High doses of reserpine cause depletion of sympathetic substances. Stria1 K+-NPPase activity was decreased after reserpine or dopamine treatment, and was increased after 5-HT, NE, and EP treatment. After reserpinization, repeated treatment with 5-HT, NE, or EP led to detectable strial enzyme activity. Thus, exogenous 5-HT, NE, and EP were able to restore strial K+-NPPase activity in the reserpine-treated animals. These results suggested that biogenic amines regulate strial K+- NPPase activity. Thus, the function of the stria vascularis may be regulated by the opposing actions of these catecholamines, and 5-HT.
Tissue and molecular events in human conjunctival scarring in ocular cicatricial pemphigoid
Detailed histomorphometric analysis of human conjunctival biopsy specimens has convincingly demonstrated that tissue remodeling of the extracellular matrix (ECM) is an essential and dynamic process associated with conjunctival scarring in ocular cicatricial pemphigoid (OCP). The conjunctival scarring often eventually results in impaired vision andlor blindness. The molecular mechanisms of conjunctival scarring are not completely understood. Accumulating evidence indicates that the early phase of conjunctival fibrosis is linked with an immuno-inflammatory process mediated by cytokines released by activated conjunctival cells and/or by infiltrating cells. Fibrogenic cytokines secreted by inflammatory cells and fibroblasts might actively be involved in remodeling of the matrix within the conjunctival stroma, possibly by regulating the altered metabolism of matrix proteins.
Villous trophoblast of human placenta: a coherent view of its turnover, repair and contributions to villous development and maturation
A coherent view of human villous trophoblast as a continuously renewing epithelium is presented. Epithelia undergoing continuous renewal (e.g. intestinal mucosa, epidermis) display clonogenic cells which pass through several transit divisions before migrating out of proliferation zones and into zones of maturation/differentiation. Quantitative relations (e.g. relative numbers of cells) between proliferation and differentiation zones help to define the steady state and this may vary in response to physiological and pathological circumstances. From the differentiation compartment, cells or cell fragments are eventually extruded by mechanisms which may involve apoptosis. All these features are seen in trophoblastic epithelium. Cytotrophoblast cells (CT, proliferation zone) divide continuously throughout gestation and post-mitotic cells are recruited into syncytiotrophoblast (ST, differentiation zone) after membrane fusion. Evidence of fusion events includes localised confluence of CT and ST cytoplasms, and intrasyncytial plasma membrane segments bearing desmosomal remnants. During differentiation, nuclei undergo changes in shape, chromatin condensation and packing density. Densely-clustered nuclei are associated with cytokeratin intermediate filaments and annulate lamellae. Both clustered and non-clustered nuclei show ultrastructural features of pre-apoptosis and apoptosis. Normally, apoptosis is triggered only when nuclei are in the syncytium. Some (pre-)apoptotic nuclear aggregates are sequestered in syncytial knots, extruded as trophoblast fragments into the intervillous space and then deported into the maternal circulation to be phagocytosed at extraplacental sites. During gestation, there is some constancy in the numerical ratios between CT and ST nuclei pointing to a normal steady state. The steady state may be perturbed when the epithelium is damaged locally. Where the epithelium is denuded, fibrin-type fibrinoid from the intervillous space plugs the discontinuity and, with CT proliferation, facilitates reepithelialisation. Features of normal villous development (e.g. sprouting, intervillous bridge formation, bridge abruption, syncytial knot formation) are explicable in the context of trophoblast turnover with early CT proliferation being mainly for growth and later proliferation for renewal and repair. Adaptive re-settings of the epithelia] steady state may also occur in abnormal pregnancies.
Gene therapy for Parkinson's disease: recent achievements and remaining challenges
Gene therapy is the use of nucleic acids as drugs. Thus, ways had to be developed to deliver this new generation of drugs to target tissues. Various viral and non-viral vectors have been engineered to carry potentially therapeutic nucleic acids into diseased organs or target cells. The brain offers a particular challenge for gene delivery to its constituent cells: it is encased by the skull, separated from the general circulation by the blood brain barrier, and made up of mostly non-dividing cells. The skull limits direct injection of vectors into the brain, the blood brain barrier inhibits the easy entry of vectors injected into the bloodstream, and post mitotic target cells restrict what type of vector can be used to deliver genes to the brain. We will discuss the main challenges faced by gene delivery to the brain, i.e. immune responses to the delivery vectors and therapeutic transgenes and length of duration of the therapy specifically as applied to Parkinson's disease. We will also discuss therapeutic strategies, which could be implemented to treat Parkinson's disease, and the models in which they have been tested.
The ultrastructural composition of basement membranes in vivo
The ultrastructure of basement membranes has a homogeneous appearance. The enormous cell biological importance of basement membranes and their components f o r c e l l proliferation, migration and differentiation implies that their composition is more complex than their structure suggests. To elucidate the molecular composition of basement membranes in vivo, we optimised immunogold histochemistry to allow the determination of the molecular arrangement of matrix molecules. Basically, we apply a mild fixation and embed the tissues in the hydrophilic LR-Gold. This reserves the basement membrane with a quality similar to freeze substitution. The application of two antibodies directed toward the C- and N-terminal ends of a molecule and coupled to gold particles of different sizes allows determination of the orientation of a molecule within the basement membrane. We were able to demonstrate that the molecular orientation of the laminin-l molecule changes in the basement membrane according to cell biological needs. We also showed that ultrastructurally identical basement membranes like the ones of the proximal and distal tubules of the kidney have a differing molecular arrangement. Integrin α7 influences the molecular composition of the basement membranes at the myotendinous junction. With the help of double labelling at the ultrastructural level we could show that nidogen-l is CO-localised with laminin-l and only found in fully developed, mature basement membranes. In general, laminin-l, nidogen-l and collagen type IV are localised over the entire width of basement membranes, with laminin-l and nidogen-l CO-localised, in accordance with the current basement membrane models. Incidentally, our investigations warn us, that not every matrix protein found at the light microscopic level as a linear staining pattern underneath an epithelium (basement membrane zone) is a real basement membrane component when investigated at the ultrastructural level. Instead, one and the same molecule, e.g. endostatin, can be a basement membrane component in one organ and a matrix molecule in another.
Transdifferentiation in neoplastic development and its pathological implication
Transdifferentiation is a process in which a cell committed to a particular specialization changes to another quite distinct type. It occurs during embryological development and some pathological processes, and causes the tumor cells to express a phenotype different from that of their normal progenitors. Neoplastic transdifferentiation involves pathogenesis of cancer subtype, transition between neoplastic epithelia and neuroendocrine cell, transition between neoplastic epithelia and mesenchyme, as well as transition between non-neuroectodermal and neuroectodermal cells. We propose that differentiation disturbance of cancer cells should include not only lower-, un-, or de-differentiation, but also transdifferentiation. Tumor cell transdifferentiation results from genetic instabilities. In some type of neoplastic transition, the initiation may be induced by extracellular matrix and growth factors.
proadrenomedullin-derived peptides as autocrine-paracrine regulators of cell growth
Proadrenomedullin (pADM)-derived peptides, adrenomedullin (ADM) and pADM N-terminal 20 peptide (PAMP), are hypotensive peptides, which are expressed, along with their receptors, in several tissues and organs, the function of which they regulate by acting in an autocrine-paracrine manner. Apart from their involvement in the regulation of blood pressure and fluid and electrolyte homeostasis, pADM-derived peptides appear to play a role in the modulation of cell and tissue growth. Evidence has been provided that ADM: 1) favors the remodeling of cardiovascular system under pathological conditions, by exerting an antiapoptotic effect on endothelial cells and an antiproliferogenic and antimigratory action on vascular smooth-muscle cells during neointimal hyperplasia, and by decreasing proliferation and protein synthesis of cardiac myocytes and fibroblasts. These last two effects are mediated by calcitonin gene-related peptide type 1 (CGRPl) receptors coupled to the adenylate cyclase (AC)/protein kinase (PK) A-dependent cascade; 2) inhibits proliferation and enhances apoptosis of kidney mesangial cells, through the modulation of mitogenactivated PK (MAPK) cascades; 3) stimulates proliferation of adrenal zona glomerulosa cells, acting via CGRPl receptor coupled to the tyrosine kinasedependent MAPK cascade, thereby possibly being involved in the maintenance and stimulation of adrenal growth; 4) enhances proliferation of skin and mucosa epithelia1 cells and fibroblasts, by activating CGRPl receptor coupled to the ACIPKA signaling pathway; and 5) enhances proliferation of several tumor-cell lines through the activation of the ACIPKA cascade, which suggests a potential role for ADM as promoter of neoplastic growth. The growth effects of PAMP have been far less investigated: findings indicate that this peptide, like ADM, enhances adrenal zona glomerulosacell proliferation, and, in contrast with ADM, depresses DNA synthesis in some cancer-cell lines. Both pADMderived peptides are thought to be involved in embryogenesis, such a contention being based on the demonstration of high pADM-gene expression during the crucial phases of organ growth and differentiation.
Hepatitis C virus-associated mixed cryoglobulinemia. Clinical manifestations, histopathological changes, mechanisms of cryoprecipitation and options of treatment
Chronic hepatitis C virus (HCV) infection is frequently associated with a variety of autoimmune phenomenons. Mixed cryoglobulinemia (MC) appears in up t o 50% o f chronic HCV-infected patients. Cryoglobulins consist of immunoglobulin complexes precipitating in vitro when cooled below body temperature. In most cases IgM with rheumatoid factor activity is found in cryoprecipitates which could lead to vasculitis induced by the deposition of immnuocomplexes in small vessels. This vasculitis is thought to cause clinical symptoms called Meltzer's triad. This triad is represented by purpura, arthralgia and weakness. One third of patients suffering from HCV-associated mixed cryoglobulinemia are developing typical symptoms during their course of disease. The striking association between HCV infection and MC has conduced to the hypothesis that HCV is of major importance in the production of MC with followed vasculitis. Both hepatrophism and lymphotrophism have been reported for the hepatitis C virus. Infection of B-cells by HCV could probably lead to a bcl-2 translocation and immunoglobulin gene rearrangement which results in clonal lymphoproliferation and in synthesis of monoclonal IgM with rheumatoid factor activity. These IgM form immunocomplexes with IgG in the cold, which are finally responsible for the described vasculitis. Histopathological changes of the liver are dominated by chronic HCV infection. The majority of times mild activity of hepatitis or mild fibrosis could be found. Nevertheless, cirrhosis is more often found in HCVinfected patients suffering from MC compared to patients without MC. Conventional treatment of MC is aimed to reduce circulating immune complexes by immunosupression and plasmapheresis. With the emerging concept of a viral pathogenesis the therapeutic approach has changed during the last decade. Interferon treatment of MC, particularly of HCV-associated MC is well established nowadays.
Recent progress in T-cadherin (CDHI 3, H-cadherin) research
T-cadherin is a unique cadherin cell adhesion molecule that is anchored to the cell surface membrane through a glycosyl phosphatidyl inositol (GPI) moiety. The cytoplasmic domain, which T-cadherin lacks, is believed to be critical for homophilic binding through interaction with submembrane cytoskeletal proteins. Docs this mean that T-cadherin is an unimportant molecule'? However, the T-cadherin amino acid motif has been well conserved through evolution in vertebrates, suggesting that T-cadherin may have biological significance in higher animals. Consistent with this hypothesis, recent studies have thrown light on the relevance of T-cadherin in the fields of ontology, neurology, respirology and cardiovascular physiology. In this manuscript, we review current advances In Tcadherin research.