Histology and histopathology Vol.12, nº 1 (1997)

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A histopathological study of anoxic-resuscitated liver allografts
(Murcia : F. Hernández, 1997) Jurado, F.; Buján, J.; Mora, M.P.; Jiménez, M.; Arahuetes, Rosa María; Bellón, J.M.
The possibility of resuscitating livers after warm ischaemia has been recently suggested. The aim of the present investigation was to analyse the effects of anoxia on the morphology of hepatic cells, to determine whether these effects are reversible after providing a resuscitation period between warm ischaemia (WI) and cooling, and to study the behaviour of the resuscitated liver in the recipient organism. Ten female, Large-White pigs acted as donors for 10 recipient animals of the same kind who received an orthotopic liver graft. Recipients were divided into two groups depending on whether the livers they received had undergone a resuscitation period (Group 1 (n=5) where animal livers were subjected to 5 min warm ischaemia (WI) without resuscitation, and Group 11 (n=5) where the livers were subjected to 5 min WI followed by 5 min resuscitation). Morphological and ultrastructural studies of liver cells were performed using light and electron microscopy. ATP, ADP and AMP levels were determined in liver biopsies by high performance liquid chromatography (HPLC). Plasma AST and bilirubin levels in the two groups were compared 24 h after transplantation. After 5 min of anoxia, hepatocytes showed two morphological pattems in response to WI. Some were appreciably condensed with dark mitochondria, peroxisomes and some cytoplasmic vacuoles. Others showed electronlucent organelles, inflamed mitochondria with broken cristae and disorganized endoplasmic reticulum. Hepatocytes showed globular microvilli and bleb formation with migration towards the sinusoids. One hour after the revascularisation of the resuscitated livers, the hepatocytes showed nearly normal morphological characteristics. However, the hepatocytes of nonresuscitated organs continued to show alterations. Kupffer cells were activated in the livers of both experimental groups. Ultrastructural changes and total tissue adenine nucleotide (TAN) levels recovered completely in resuscitated livers soon after transplant. These results suggest that when short WI periods are followed by equivalent periods of resuscitation, the hepatocytes of transplanted livers recover from the effects of anoxia.
Open Access
Cytomorphological changes in the rabbit oviductal epithelium after human chorionic gonadotropin treatment
(Murcia : F. Hernández, 1997) Bondi, A.M.; Gabrielli, M.G.; Marchetti, L.; Materazzi, G.; Menghi, Giovanna
An electron microscopic investigation was performed to examine the ultrastructural changes occurring in the rabbit oviductal epithelium after human chorionic gonadotropin (HCG) administration. Mainly, the non-ciliated secretory cells proved to be affected by the hormonal treatment which resulted in qualitative and quantitative modifications of the secretory patterns differently expressed in the ampulla and isthmus. Thus, morphological evidence of intense secretion was observed in both the oviduct regions at preovulatory stages. Following ovulation, timing of expression of active secretory patterns in the ampulla and isthmus correlated well with the rate of gamete transport and relative functional roles of the oviductal regions in the reproductive process. At present, HCG-induced changes concerning the ciliated cells seem to consist of the occurrence of secretory granules responsible for the appearance of "mixed cells".
Open Access
The role of dystroglycan, a novel receptor of laminin and agrin, in cell differentiation
(Murcia : F. Hernández, 1997) Matsumura, K.; Yamada, H.; Saito, F.; Sunada, Y.; Shimizu, T.
Dystroglycan was originally identified as the extracellular and transmembrane constituents of a large oligomeric complex of sarcolemmal proteins associated with dystrophin, the protein product of the Duchenne muscular dystrophy (DMD) gene. During the last few years, dystroglycan has been demonstrated to be a novel receptor of not only laminin but also agrin, two major proteins of the extracellular matrix having distinct biological effects. The fact that the drastic reduction of dystroglycan in the sarcolemma, caused by the absence of dystrophin, leads to muscle cell death in DMD patients and mdx mice indicates that, as a laminin receptor, dystroglycan contributes to sarcolemmal stabilization during contraction and stretch of striated muscle cells. Dystroglycan is also expressed in the neuromuscular junction and non-muscle tissues such as kidney, brain and peripheral nerve, and, as a receptor of lamininlagrin, has been implicated in such diverse and specific developmental processes as epithelial morphogenesis, synaptogenesis and myelinogenesis. These findings point to the fundamental role of dystroglycan in the cellular differentiation process shared by many different cell types. In this paper, we review the recent publications on the biological functions of dystroglycan and discuss its roles in cell differentiation.
Open Access
Electron microscopic study of sprouting dendrites in the ciliary ganglia of cat and monkey (Macaca fascicularís) following pre- and post-ganglionic axotomy
(Murcia : F. Hernández, 1997) Zhang, Y.L.; Tan, C.K.; Wong, W. C.
The present paper reports the ultrastructure of dendritic sprouting and formation of associated synapses in the ciliary ganglion of cat and monkey induced by pre- and post-ganglionic axotomy. In both series of experiments, sprouting dendrites were observed mostly at 3-5 days postoperatively; such profiles were identified by their dense packing of mitochondria and glycogen-like granules. In longitudinal section, such profiles appeared as expanded extensions from the normal-looking dendritic trunks. None were observed to arise directly from the neuronal soma. After preganglionic nerve section, the cross-sectional diameters of such profiles measured 2.211 .O pm (range: 0.9-6.2 pm) in cat and 2.4I0.7 y m (range: 0.9-5.5 pm) in monkey. After postganglionic nerve section, the crosssectional diameters of such profiles measured 2.110.7 pm (range: 0.8-4.5 pm) in cat and 2.811.4 pm (range: 1.1-7 .O p m) in monkey. After preganglionic axotomy, in both cat and monkey, the axon terminals began to degenerate at 3 days postoperatively and disappeared by 5 days postoperatively. However, at later postoperative survival periods, the axon terminals reappeared and were observed to make synaptic contacts with the sprouting dendrites. Some of the sprouting dendrites were observed to degenerate, some as early as 3 days postoperatively; such profiles did not appear to have any synapse on them. After postganglionic axotomy, such sprouting dendritic profiles were also observed to make synaptic contacts with axon terminals; some were only closely associated with profiles filled with synaptic vesicles. The results thus suggest that through the formation of new synapses, sprouting of dendrites may have a role to play in neuronal survival after axotomy.
Open Access
The phylogenetic odyssey of the erythrocyte. IV. The amphibians
(Murcia : F. Hernández, 1997) Glomski, Chester A.; Tamburlin, Judith; Hard, R.; Chainani, Meena
Amphibians manifest permanently nucleated, oval, flattened, biconvex erythrocytes. These cells demonstrate a cytoskeleton which is responsible for their morphogenetic conversion from a sphere to an ellipse and imparts to their cellular mass reversibility of traumatic deformation. The class Amphibia has the largest of al1 erythrocytes attaining volumes greater than 10,000 femtoliters in the Amphiuma. The large dimensions reflect evolutionary processes, genomic size, ploidy and the relative size of other somatic cells. Conversely, the erythrocyte count and hemoglobin concentration of these species are low. Occasional denucleated red cells can be seen in the peripheral blood but may attain levels of 90-95% of the total circulating population in certain members of the tribe Bolitoglossini (e.g. Batrachoseps attenuatus). These erythroplastids retain the marginal band thus remaining different from mammalian erythrocytes. Embryologically, erythropoiesis initiates in the yolk sac and then progreses to the kidney, liver, and possibly spleen. The yolk sac cohort is transitory and is successively replaced by the larval and definitive populations of erythrocytes. Red cell production (along with thrombocytopoiesis) in adult urodeles is conducted intravascularly in the spleen. In anurans this organ is usually the major site although the liver also serves as a secondary locus for this activity. Medullary (bone marrow) erythropoiesis makes its phylogenetic debut in anurans and typically occurs during heightened hemopoiesis following metamorphosis or hibernation. Maturation of the erythrocyte in the circulation is commonplace (especially in urodeles) while proliferation at this site is inducible by splenectomy andlor hemolysins. Erythrocyte-related values demonstrate variable differences associated with age, weight, season, gender, and environment.
Open Access
An evaluation of the role of nuclear cytoplasmic ratios and nuclear volume densities as diagnostic indicators in metaplastic, dysplastic and neoplastic lesions of the human cheek
(Murcia : F. Hernández, 1997) White, F.H.; Jin, Y.; Yang, Ling
The increase in nuclear cytoplasmic (NIC) ratio is one of the features of cellular atypia which is used in the histopathological assessment of premalignant lesions of the oral mucosa. Since this feature is readily quantifiable using morphometry, we have analysed both N/C and nuclear volume densities in basal and spinous cells from human cheek lesions with and without malignant potential in order to ascertain the validity of this parameter as a predictor. Using a strictly standardised sampling procedure, measurements of cellular and nuclear areas of basal and spinous cells from normal and pathological human cheek mucosa were made on haematoxylin and eosin-stained sections using a VIDAS image analyser. Cases examined comprised fibrous hyperplasia (FH), traumatic inflammation (IF), benign hyperkeratosis (HK), lichen planus (LI), leukoplakia with dysplasia (DYS), squamous cell papilloma (PP), dysplastic epithelium from the edges adjacent to invasive carcinoma (CE) and islands from invasive squamous cell carcinoma (CI). In basal cells, NIC ratios and nuclear volume densities were lower than values obtained for the normal controls. In spinous cells, these parameters were elevated in the potentially premalignant lesions (DYS, CE) as well as in CI but values were similarly elevated in FH, IF, HK and PP, lesions which appear to have no malignant potential. The NIC ratio is of no value as a predictor of malignant potential in basal or spinous cells from cheek lesions. The putative increase in NIC which has been previously described qualitatively is probably due to increased nuclear hyperchromatism, which may provide an illusory increase in relative nuclear size at the expense of the cytoplasm.
Open Access
The contribution of type II pneumocytes and alveolar macrophages to fibroplasia processes in the course of enzymatic lung injury
(Murcia : F. Hernández, 1997) Sulkowska, M.; Sulkowski, S.
The aim of the paper was to evaluate mutual relations in the system of alveolar macrophage (AM) - type 11 pneumocyte (PII) - interstitium of alveolar septa, in the course of experimental lung emphysema in rats subjected to BCG vaccine effect. Administration of BCG vaccine resulted in the cumulation of AM within pulmonary alveoli. These cells exhibited morphological features of increased activity. Intratracheal papain injection induced intralobular emphysema changes, partly generalized, in the animal lungs. The emphysematous changes, with domination of interalveolar septum atrophy, were accompanied by foca1 accumulation of collagen and elastin. Fibroplasia processes were strongly pronounced in BCG- and papain-treated animals. The areas of connective tissue fibres cumulation revealed indistinctness of the boundary line between PII and the interstitium in some places. Anchorage of collagen fibres and microfibrillary structures were observed in the cytoplasm of PII. The morphological examinations of AM - fibroblasts co-cultures as well as the evaluation of the uptake of 3 ~ - thymidine did not show any significant differences between respective co-cultures of fibroblasts and AM isolated both from the lungs of control and experimental animals (treated with BCG or papain, and BCG+papain). However, a significant growth was noted in 3 ~ - thymidine uptake between fibroblast cultures realized with or without cells isolated from the lungs. The results obtained suggest the possibility of active participation of PII and AM in fibroplasia processes in the course of lung rebuilding after papain administration and in pathological states of the pulmonary tissue, particularly when they are accompanied by increased activity of alveolar macrophages. They also support the inflammatory-repair hypothesis in the development of emphysematous changes.
Open Access
Morphometric studies on the development of the human thyroid gland. II. The late fetal life
(Murcia : F. Hernández, 1997) Bocian-Sobkowska, J.; Wozniak, W.; Malendowicz, L.K.
Histological and morphometric studies were performed on 27 thyroid glands obtained from normal fetuses ranging between 23 to 40 weeks of intra-uterine life. In the thyroids the volume of gland, colloid, and stroma were calculated by means of differential pointcounting method and the height of the thyroid follicular cells was measured. Moreover, the epithelium/colloid ratio in the thyroid gland, a very sensitive parameter of stimulation of the glands by TSH, was calculated. Regarding the values of this ratio in human fetal thyroid gland, the intra-uterine development of the gland may be divided into three distinct stages. The first one, between weeks 10- 18 is characterized by massive folliculogenesis and gradual accumulation of the colloid. The second stage, between weeks 19-29 of fetal life is characterized by rather unchanged values of epithelium/colloid ratio and the size of follicles. The third stage, after the 29th week of development is characterized by a gradual increase in the epithelium/colloid ratio and a decrease in the size of follicles.
Open Access
The Thomsen-Friedenreich (TF) antigen: a critical review on the structural, biosynthetic and histochemica aspects of a pancarcinoma-associated antigen
(Murcia : F. Hernández, 1997) Hanisch, F.G.; Baldus, S.E.
Within the family of blood-group related carbohydrate antigens the Thomsen-Friedenreich (TF) antigen (or T antigen) is an outstanding member by attracting scientific interest for more than 65 years and by having retained its significance as object of current biomedical research; in particular, as a pancarcinoma-associated antigen. In accordance with its constant or even growing attraction scientists have searched for specific reagents which would allow the unambiguous and sensitive detection of the Thomsen-Friedenreich antigen on cells or tissues. While at the beginning, immunohistochemical work on TF antigen expression was restricted by the limited specificity of plant lectins (peanut lectin) a significant progress has been possible since the introduction of the hybridoma technique. The respective monoclonal antibodies display distinct fine specificities and cellular staining patterns in immunohistochemistry and have contributed to controversia1 discussions on the organ-characteristic and tumor-associated expression of the TF antigen in some organs. It is the aim of this survey to summarize in the context of its structural and biosynthetic aspects the current knowledge on the tissue expression of the TF antigen as based on the use of peanut agglutinin and monoclonal antibodies and to discuss the findings with regard to their biomedical relevance, in particular, with emphasis on their value in tumor diagnosis.
Open Access
K-FGF protoncogene expression is associated with murine testicular teratogenesis, but is not involved during mouse testicular development
(Murcia : F. Hernández, 1997) Anta, J.M.de; Monzó, M.; Peris, B.; Ruano, D.
The k-FGF gene, which belongs to the family of the fibroblast growth factor genes, is implicated in tumoral and developmental processes. It is expressed in embryonal carcinoma cells, in embryonic stem cells, during limb and tooth formation and in some germ cell tumors. However, the expression of this protooncogene during testicular development as well its relationship to spontaneous teratogenesis have not been determined. Here we investigate k-FGF expression during testicular development in mice, as well as in a spontaneous testicular teratoma (STT) and in the OTT6050 teratocarcinoma (TC) by Northern blotting, RT-PCR and in situ hybridization. Severa1 data indicate that k-FGF gene contains downstream regulatory sequences which bind octamer factors. One of these transcription factors which binds to k-FGF enhancer is Oct-4. Although the k-FGF gene is activated by Oct-4 in embryonal carcinoma and embryonic stem cells and Oct-4 is expressed in the germ cells of the embryo, our results indicate that there is no detectable k-FGF expression in mouse testicular germ cells at any stage of development. This indicates that Oct-4 does not activate transcription of the k-FGF gene in mouse germ cells, and that k-FGF is not implicated during testicular development. We also show that there is a high k-FGF expression in the experimental OTT6050 TC, but only very low levels in a murine differentiated STT, suggesting that k-FGF activation may be responsible for the genesis and development of STT, behaving as a marker of malignancy in these neoplasms .
Open Access
Compartmentation of the granular layer of the cerebellum
(Murcia : F. Hernández, 1997) Ozol, K.O.; Hawkes, R.
Numerous studies have demonstrated that the cerebellum is highly compartmentalized. In most cases, compartmentation involves the Purkinje cells and the molecular layer, but there is also substantial evidence that the granular layer is subdivided into a large number of highly reproducible modules. We first review the evidence for a modular granular layer. Compartmentation of the granular layer has been revealed both functionally and structurally. First, tactile receptive field mapping has revealed numerous discrete functional modules within the granular layer. The molecular correlates of the receptive fields may be the compartments revealed by histological staining of the cerebellum for several enzymes and antigens. The structural substrate of the receptive fields is the mossy fiber afferent projection map, and anterograde tracing of various mossy fiber projections shows afferent terminals in parasagittal bands within the granular layer that are topographically aligned with the Purkinje cell compartments. Based on this evidence we argue that the cerebellum consists of many hundreds of reproducible structural/functiona1 modules, and that a modular organization is a prerequisite for the efficient parallel processing of information during motor control. The complex organization of the adult granular layer implies elaborate developmental mechanisms. In the second part of the review we consider five developmental models to generate the modular organization of the adult granular layer: 1) the external granular layer is heterogeneous, and its topography translates directly into a modular granular layer; 2) granular layer modules are clones, derived from single external granular layer precursors; 3) modules in the granular layers are a secondary epigenetic response to the compartmentation of the Purkinje cells; 4) modules are secondary to the compartmentation of the afferent terminal fields; 5) modules are sculpted by activitydependent processes.
Open Access
Biocompati bility and osteoconductivity of the pyrost bone substitutes
(Murcia : F. Hernández, 1997) Tsuang, Y.H.; Lin, F.H.; Tai, H.C.; Sun, J.S.; Liu, H.C.; Hang, Y. S.
The purpose of this study was to re-evaluate the bone regeneration power and the in vitro biocompatibility of the Pyrost bone substitute. Twentyfour adult New Zealand White rabbits were used. Bony defect over both iliac crest and mid-diaphyseal portion of the ulna bone were created. Appropriate sized-block of Pyrost bone substitute were implanted. Four of the animals were killed at each postoperative month to evaluate its bone regeneration power by histologic study. The Pyrost bones were co-cultured with osteoblasts to evaluate its biocompatibility. The results showed that Pyrost bone substitute was quite stable and incorporated well with active bone regeneration. The Pyrost heal better at the iliac crest than at the ulnar defect. The Pyrost was compatible to the osteoblasts. Osteoblasts had successfully seeded and mitotically expanded on the porous surface of the Pyrost bone graft. The result showed that Pyrost bone obviously exerts an intense stimulus on osteo-regeneration in the presence of osteoblasts. We consider Pyrost to be an altemate to the conventional preserved allografts that is occasionally necessary.
Open Access
lmmunohistochemical expression of Bcl-2 oncoprotein in EBV-associated nasopharyngeal carcinoma correlated to histological type and survival
(Murcia : F. Hernández, 1997) vera-Sempere, F.J.; Burgos, J.S.; Botella, M.S.; Morera, C.
Expression of Bcl-2 is associated with inhibition of apoptosis and extension of cell survival. In vitro Bcl-2 protein expression is up-regulated by the EBV-latency associated antigen latent membrane protein (LMP-1). We have investigated the relationship between the presence of EBV-DNA screened by means of sensitive nested-PCR, nasopharyngeal carcinoma (NPC) histological types according to two different schemata (WHO and Micheau classifications) and Bcl-2-124 immunohistochemical expression in 55 biopsy samples of NPC. EBV genome was detected in 100% of samples with sufficient DNA quality to support the previous view that al1 types of NPC are variants of EBV-infected neoplasia. Bcl-2 was observed in the basa1 layer of normal nasopharyngeal mucosa and also at cytoplasmic level in 42 of 55 (76.4%) NPC cases. Mitotic neoplastic cells usually showed strong cytoplasmic and chromosomal staining, a finding not well referred to previously. Bcl-2 expression was significantly associated (p<0.05) to undifferentiated NPC (UNPC) when a histological classification with only two major microscopical types was applied. No close correlations were found between the presence of EBV-DNA, NPC location, clinical stage and age or sex of the patients in relation to Bcl-2 positive expression. However, when comparing Bcl-2 expression and known survival mean of the patients, significant differences were observed (p<0.001) so that mean survivals were 3 1.1, 24.4, 52.2 and 54.1 months respectively for NPC patients with -, +, ++ and +++ Bcl-2 immunoreactivity. Nevertheless this better clinical outcome in Bcl-2 NPC positive cases may depend on the histological type due to close relationship with UNPC. Only studies of larger series with long-term follow-up and multivariate analyses may document whether Bcl-2 expression is an independent prognostic marker in the evolution of NPC patients.
Open Access
Ultrastructural characteristics of blood vessels in the infant and adult human cerebral cortex
(Murcia : F. Hernández, 1997) Zhang, H.F.; Ong, W.Y.; Leong, S.K.; Garey, L.J.
Blood vessels in frontal and temporal cerebral cortex of adults and two infants aged 5 months and 5 years were studied by electron microscopy. The cells outside the endothelium were classified on their ultrastructural characteristics. Fibroblasts had prominent rough endoplasmic reticulum and few mitochondria in the cytoplasm. They were different from pericytes, which contained a prominent Golgi apparatus but only a few, isolated profiles of rough endoplasmic reticulum. Smooth muscle cells were distinguished from fibroblasts and pericytes by the presence of filaments and caveolae. Perivascular cells were characterised by the presence of lysosomes and granules of different sizes and electron densities, and were present at al1 ages studied. Plasma cells had abundant rough endoplasmic reticulum in the cytoplasm, and were present only in the 5-month-old infant cortex. Cortical vessel diameter increased with age.
Open Access
Apoptosis and autophagy in nigral neurons of patients with Parkinson's disease
(Murcia : F. Hernández, 1997) Anglade, P.; Vyas, S.; Javoy-Agid, F.; Michel, P.P.; Marquez, J.; Mouatt-Prigent, A.; Ruberg, M.; Hirsch, E.C.; Agid, Y.; Herrero Ezquerro, María Trinidad
Parkinson's disease (PD) is a neurodegenerative disorder characterized by progressive cell loss confined mostly to dopaminergic neurons of the substantia nigra. Several factors, including oxidative stress, and decreased activity of complex 1 mitochondrial respiratory chain, are involved in the degenerative process. Yet, the underlying mechanisms leading to dopaminergic cell loss remain elusive. Morphological assessrnent for different modes of cell death: apoptosis, necrosis or autophagic degeneration, can contribute significantly to the understanding of this neurona1 loss. Ultrastructural examination revealed characteristics of apoptosis and autophagic degeneration in melanized neurons of the substantia nigra in PD patients. The results suggest that even at the final stage of the disease, the dopaminergic neurons are undergoing active process of cell death.
Open Access
Gap junction channel: new roles in disease
(Murcia : F. Hernández, 1997) Donaldson, P.; Ecker, R.; Green, C.; Kistler, J.
The irnportance of intercellular communication to complex cellular processes such as development, differentiation, growth, propagation of electrical impulses and diffusional feeding has long been appreciated. The realization that intercellular communication is mediated by gap junction channels, which are in turn comprised of a diverse family of proteins called the connexins, has provided new tools and avenues for studying the role of intercellular communication in these important cellular processes. The identification of different connexin isoforms has not only enabled the development of specific reagents to study connexin expression patterns, but has also allowed the functional properties of the different connexin isoforms and how they interact with each other, to be explored. Increasingly, the knowledge gained from studying connexin diversity is being used to investigate the role played by gap junction channels in a number of diseases. In this article we highlight selected cases where gap junction channels have been shown or are believed to be directly involved in the disease process.
Open Access
Triton tumor of the parotid area. Case report
(Murcia : F. Hernández, 1997) Llanes, F.; Sanz Ortega, J.; Suarez, B.; Sanz Esponera, J.
A 27-year-old woman with a Malignant Triton Tumor (MTT), or malignant schwannoma with rhabdomyoblastic differentiation, located in the parotid cell and infiltrating the nasal sinuses and the left orbit is described. The initially resected tumor showed three recurrences within a 2 years follow-up period. During successive recurrences an increase in cellular density, number of mitoses and necrosis was noticed. Immunohistochemical analysis showed that the tumor was composed of a mixed population of cells. Some of them showed positivity for actin, desmin and myoglobin, while others were positive for S-100 protein, glial fibrillary acid protein, and IV-collagen. Cytokeratin stainings were negative. Up to now, 8 benign triton tumors and another 45 cases of MTT have been described. None of them was primarily located in the parotid gland, and infiltration to the orbital cavity has not been previously described.
Open Access
T cell subsets in immunologically-mediated glomerulonephritis
(Murcia : F. Hernández, 1997) van Alderwegen, I.E.; Bruijn, J.A.; Heer, E.de
Until recently, research on the pathogenesis of glomerulonephritis has been mainly focused on the characterization of humoral immune responses in the initiation of glomerular injury. However, there is a growing recognition that both cellular and humoral immune responses, in varying proportions, are involved in the pathogenesis of immunologically-mediated glomerulonephritis. T lymphocytes are essential cellular elements of cell-mediated immunity. Both in experimental models of immune-mediated renal disease and in histopathological analyses of human nephropathies, the involvement of T cells has been demonstrated in the immunoregulation of nephritogenic immune responses and in the immune injury in the kidney. T cell activation resulting in either delayed-type hypersensitivity, cytolytic reactions, abnormal expression of major histocompatibility complex (MHC) molecules, or B cell activation can result in glomerulonephritis. These different types of responses are exerted by distinct T cell subsets defined by cell surface markers and cytokine profiles. CD4+ T cells in vivo are functionally heterogeneous with respect to cytokine production and the CD45 isoforms that are found on their surface. Like CD4+ T cells, CD8+ T cells may also be heterogeneous at the leve1 of cytokine production. The roles of CD4+ and CD8+ cells and their cytokine profiles in glomerulonephritis have not been extensively investigated yet, but such studies might improve the understanding of the pathogenesis and possibly lead to new therapeutic approaches of human glomerulonephritis. In this review the role of distinct T lymphocyte subsets in experimental and human glomerulonephritis will be discussed.
Open Access
Duodenal and gastric cell regenerating epithelia on margins of human duodenal ulcer and presence of H. pylori - An electron microscopic study
(Murcia : F. Hernández, 1997) Ogata, T.
Specimens from 22 cases of human duodenal ulcers obtained at surgery were studied by transmission and scanning electron microscopy. Observations were focused on the ulcer margins which always showed some evidence of healing by simple cuboidal epithelial cells migrating on the ulcer base. Two types of regenerating epithelia (RE) were found: the intestinal and the gastric cell types. The intestinal type RE originating from intestinal epithelium of the surrounding epithelium of the ulcer edge was composed of immature enterocytes, which differentiated into absorptive and goblet cells, and formed presumptive crypts and villi. The gastric type RE grew from adjacent metaplastic gastric mucosa at the edge of the ulcer and consisted of immature cells, which developed into mucous cells. Some ulcers had RE of both intestinal cell and gastric cell origin. In most margins, the RE was of only one cell type, but in others both intestinal and gastric type cells were present. In more developed regions both types formed presumptive glands. The basa1 lamina was frequently missing near the leading edge. This corresponded to degeneration and necrosis of RE, especially in areas of severe inflammatory foci. Helicobacter (H.) pylori colonization on gastric metaplastic epithelium was observed in about one third of the ulcer cases. In the surrounding epithelium of ulcers colonized with H. pylori there were degenerative changes, disruption of cell membranes, and massive cell exfoliation resulting in denuded lamina propria. Some gastric type RE was also colonized with H. pylori. No infection was found on intestinal epithelia. These findings suggest that H. pylori may be important in the development of duodenal ulcers as well as in the prevention or delay of ulcer healing.
Open Access
Roles of integrins in fibronectin matrix assembly
(Murcia : F. Hernández, 1997) Wu, C.
Fibronectin (Fn) matrix assembly is a dynamic cellular process in which the soluble dimeric Fn molecules are assembled into insoluble, disulfide bond stabilized fibrillar polymeric matrix. Fn matrix assembly requires specific Fn binding integrins. Several Fn binding integrins that are capable of mediating Fn matrix assembly have been identified. They include a5B1, aIIbB3 and ctvB3 integrins. Cells regulate the matrix assembly process not only by controlling cell surface expression leve1 of the Fn binding integrins but also by modulating Fn binding and cytoskeleton binding activities of the integrins. A major challenge of future studies is to delineate the signal transduction pathway that regulates Fn matrix assembly