Biomedical subjects

R Paniagua

Publications and source records attributed to R Paniagua.

At least 55 records · Page 3Linked to original sources

PubMed1999

Alpha-actinin in different invertebrate muscle cell types of Drosophila melanogaster, the earthworm Eisenia foetida, and the snail Helix aspersa.

The presence and distribution of alpha-actinin has been studied in several invertebrate muscle cell types. These comprised transversely striated muscle (flight muscle) from the fruit fly Drosophila melanogaster, transversely striated muscle (heart muscle) from the snail Helix aspersa, obliquely striated muscle (body wall muscle) from the earthworm Eisenia foetida, smooth muscle (retractor muscle) from H. aspersa, and smooth muscle (outer muscular layer of the pseudoheart) from E. foetida. The study was carried by means of Western blot analysis, ELISA, and immunohistochemical electron microscopy, using anti alpha-actinin antibody. Immunoreaction for a protein with the same molecular weight as that of mammalian alpha-actinin was detected in all muscle types studied, although the amount and intensity of immunoreaction varied among them. In the insect muscle, immunolabelling was found along the whole Z-line. In both the transversely striated muscle from the snail and the obliquely striated muscle from the earthworm, immunolabelling did not occupy the whole Z-line but showed discontinuous, orderly arranged patches along the Z-line course. In the two smooth muscles studied (snail and earthworm), immunolabelling was limited to small patches which did not show an apparently ordered distribution. Since it is assumed that alpha-actinin is located at the anchorage sites for actin filaments, present observations suggest that, only in the Drosophila muscle, actin filaments are parallelly arranged in all their course, whereas in the other invertebrate muscles studied these filaments converge on discontinuously distributed anchorage sites.

Actin Cytoskeleton↗

PubMed1999

A lectin histochemistry comparative study in human normal prostate, benign prostatic hyperplasia, and prostatic carcinoma.

The partial oligosaccharide sequences of glycoconjugates and the nature of their glycosidic linkages were investigated in normal human prostate, benign prostatic hyperplasia (BPH) and prostatic carcinoma by means of lectin histochemistry, using light microscopy and Western blot analysis. The labeling pattern of BPH differed from that of normal prostate in having more intense staining with DSA, HPA, UEA-I and AAA, and in showing lesser staining with WGA and SBA. Prostatic carcinoma differed from normal prostates in displaying the more intense labeling with PNA, DSA, SBA, DBA, UEA-I and AAA, and in having lesser labeling with WGA. The main differences in labeling pattern between prostatic carcinoma and BPH were that the latter specimens showed more marked staining with PNA, DSA, DBA, SBA, UEA-I and AAA, and lesser staining with WGA and HPA. The staining patterns of SNA, MAA, ConA, LCA and GNA were similar in all three groups of specimens. For most of the lectins studied, including those showing a similar immunohistochemical staining in the three groups of specimens studied, the Western blot analysis showed differences in the banding pattern among normal, hyperplastic, and carcinomatous prostates. Present results suggest that the glycosylation of proteins was modified in both BPH and prostatic carcinoma. In BPH a strong expression of N-acetylgalactosamine residues occurred, while in prostatic carcinoma an increase of sialic acid, galactose and fucose residues was observed. No changes in mannose residues were detected.

Adult↗

PubMed1999

The hatching gland cells of trout embryos: characterisation of N- and O-linked oligosaccharides.

A histochemical, light and electron microscopy study of the hatching gland cells (HGCs) in incubated 50-d-old trout embryos is reported. The distribution of carbohydrate residues in the glycoconjugates of these cells was studied by means of a battery of 13 different lectins conjugated with horseradish peroxidase (PNA, ConA, LCA, WGA, SBA, UEA-I, HPA, DBA) or digoxigenin (DSA, MAA, AAA, SNA, GNA). Identification of N- and O-linked oligosaccharides in HGCs was performed by application of both chemical and enzymatic treatments. Present results suggest that HGCs are seromucous cells which store both high choriolytic enzyme (HCE) and low choriolytic enzyme (LCE), and that their cytoplasmic granules, endoplasmic reticulum and Golgi complex contain additional sialic acid-rich glycoproteins. The negative charge of these glycoproteins might be responsible for the rapid expansion of mucin to form a highly hydrated gel, which would facilite the action of these enzymes in programmed cell death and might play a major role during the morphogenic events.

Animals↗

PubMed1999

Testicular biopsy in patients with obstructive azoospermia.

The present report studies the testicular biopsy lesions (histologic and semiquantitative) in a series of 48 patients with obstructive azoospermia of known etiology (vasectomy, congenital absence of vas deferens, herniorrhaphy, hydrocelectomy, Young's syndrome, and ejaculatory duct obstruction) in order to establish objective testicular data that permit the pathologist to diagnose an obstructive process, which should not be mistaken with a primary testicular lesion. The semiquantitative study included determinations of the average numbers of spermatogonia, primary spermatocytes, young spermatids (Sa + Sb), and differentiated spermatids (Sc + Sd). According to this study, the testes were classified into the following groups: (1) normal testes whose germ cell numbers were within normal limits (27 testes); (2) testes with lesions in the adluminal compartment; these lesions comprise two subgroups: (2a) late sloughing of primary spermatocytes (both spermatid types were greatly reduced in number while the other germ cell types were in normal numbers) (45 testes); and (2b) early sloughing of primary spermatocytes (normal spermatogonial number, reduced number of spermatocytes, and scanty spermatids) (9 testes); and (3) lesions in the basal compartment; these lesions comprise two subgroups: (3a) pure hypospermatogenesis (a proportionate decrease in the numbers of all germ cell types) (8 testes); and (3b) hypospermatogenesis associated with sloughing of primary spermatocytes (decreased numbers of all germ cell types with a very scanty number spermatids) (4 testes). Two testes appeared hyalinized and one testis was removed owing to cryptorchidism. The most frequent testicular lesion observed (alteration in the adluminal compartment of seminiferous tubules) seems to be related to the increase in hydrostatic pressure in the tight compartment formed by seminiferous tubules, rete testis, efferent ducts, the epididymal duct, and the initial portion of the vas deferens. The severity of the lesions is probably related to the cause and span of the obstruction. In addition, two azoospermic men without obstructive azoospermia and whose testicular biopsy study revealed meiotic anomalies (with the subsequent bad prognosis) were also studied for comparison. The semiquantitative study of these patients permitted the differential diagnosis between two lesion types. Testes with meiotic anomalies had a disproportionately elevated number of primary spermatocytes, and an extremely low number of young spermatids.

Adult↗

PubMed1999

Oncostatin M in the normal human testis and several testicular disorders.

The immunohistochemical reaction to oncostatin M (OSM) was studied in normal human testes at different ages (fetuses, newborns, children, pubertal boys, adults, and elderly men), as well as in several testicular disorders including carcinoma-in-situ cells (CIS), germ cell tumors, benign functioning Leydig cell tumor, androgen insensitivity syndrome, Klinefelter's syndrome, and cryptorchidism. Positive OSM immunostained Sertoli cells were only observed in fetuses. In normal testes, intense OSM immunoreaction was found in the Leydig cells of fetuses, newborns, and adults. Leydig cell immunoreaction was weak in elderly men and absent in children and pubertal boys. In some testicular disorders (Leydig cell tumor, cryptorchidism, and CIS), Leydig cell immunoreaction was as intense as in normal adult testes. This immunoreaction was heterogeneous in androgen insensitivity syndrome and was absent in Klinefelter's syndrome and intratubular seminoma. No recognizable Leydig cells were observed in the other testicular tumors. The findings of our study suggest that, in humans, the down-regulation of OSM immunoexpression in Sertoli cells occurs early, and that OSM immunoreaction in the Leydig cells is associated with functionally active and differentiated Leydig cells.

Adolescent↗

PubMed1999

Androgen insensitivity syndrome: an immunohistochemical, ultrastructural, and morphometric study.

OBJECTIVE: To evaluate the morphometric, immunohistochemical, and ultrastructural lesions of the testes in prepubertal and adult patients with androgen insensitivity syndrome. METHODS: We examined the testicular biopsy using immunohistochemistry for vimentin, smooth muscle actin, and collagen IV antigens. Quantification of seminiferous tubules and testicular interstitium was performed in prepubertal and adult patients with androgen insensitivity syndrome and results were compared with normal testes from both infants and adults. RESULTS: The adult testes presented nodular and diffuse lesions that consisted of Sertoli-cell-only seminiferous tubules. Two types of Sertoli cells could be distinguished, namely, immature vimentin-positive Sertoli cells and nearly mature Sertoli cells. In the nodules, the lamina propria was thin and contained a scant number of actin-positive peritubular cells. Leydig cells were hyperplastic. The prepubertal patients showed only diffuse lesions characterized by Sertoli cell hyperplasia, decreased germ cell numbers, and a discontinuous immunoreaction to collagen IV. CONCLUSIONS: The testicular lesions in androgen insensitivity syndrome are probably caused by primary alterations that begin during gestation. These lesions become progressively more pronounced at puberty, when the nodular lesion pattern (adenomas) is completely developed.

Adolescent↗

PubMed1998

Lectin histochemistry study in the human vas deferens.

The oligosaccharide sequences of glycoconjugates in the normal human vas deferens and the nature of the saccharide linkage were studied by lectin histochemistry. The cytoplasm of all epithelial cell types (principal cells, basal cells, and mitochondria-rich cells) and luminal contents reacted positively with WGA, MAA, PNA, DSA, LTA, UEA-I, AAA, and ConA. The reaction was more intense in the stereocilia of principal cells. Cytoplasmic staining was diffuse except for PNA and DSA labeling which was limited to the apical cytoplasm and stereocilia of columnar cells. The cytoplasm of all cell types also reacted diffusely with HPA, although staining was weak and was not observed in the stereocilia. Positive reaction with SBA only was encountered in the stereocilia of principal cells. SNA, LTA, and DBA were unreactive. GNA-labeling showed a granular distribution in the supranuclear cytoplasm of columnar epithelial cells. Reactions with MAA, PNA, DSA, AAA, HPA and SBA disappeared after the beta-elimination reaction. Reactions with WGA and UEA-I decreased after beta-elimination or Endo-F digestion. Reactions with ConA and GNA were suppressed by Endo-F digestion. Reactions with PNA, HPA, and SBA increased after desialylation. Of all the lectins that label the luminal contents of the vas deferens, only UEA-I was not found in the luminal contents of seminiferous tubules and epididymis and, thus, this lectin would probably bind to glycoproteins secreted by the vas deferens. The chemical treatments used suggest that this secretion contains fucose residues located in both N- and O-linked oligosaccharides. The other lectins may label secreted proteins, but also structural proteins or proteins reabsorbed from the luminal fluid. The lectin- binding pattern of mitochondria-rich cells in the vas deferens differed from that found in the epididymis.

Adult↗

PubMed1998

Classification of several types of maturational arrest of spermatogonia according to Sertoli cell morphology: an approach to aetiology.

Bilateral testicular biopsies and clinical histories from 34 adult men with maturational arrest of spermatogonia were examined. According to the morphology of Sertoli cell nuclei, five testicular types of spermatogonial maturational arrest were established. In type I lesion, Sertoli cells resembled the immature Sertoli cells of infant testes. These cells had a round, regularly outlined, dark nucleus with a small nucleolus. The seminiferous tubules showed no apparent lumen and a poorly developed lamina propria lacking in elastic fibres. This lesion was found in patients exhibiting a eunuchoid phenotype, with small tests and low serum levels of gonadotrophins and testosterone (hypogonadotrophic hypogonadism). Type II lesion showed morphologically normal, mature, adult Sertoli cells which had a pale, irregularly outlined nucleus, many often triangle-shaped, with a large, centrally located nucleolus. The seminiferous tubules were reduced in diameter and showed a few spermatocytes and spermatids. This lesion was found in patients with varicocoele, epididymitis, testicular trauma or idiopathic infertility. Serum FSH levels were normal or increased while LH and testosterone levels were normal. In type III lesion, Sertoli cells resembled the involuting Sertoli cells found in the testes of aging men, and displayed very infolded nuclei, with abundant dense chromatin patches and a large nucleolus. The seminiferous tubules showed a slightly dilated lumen and a normal tubular wall. The most relevant clinical findings in patients with this lesion were alcoholism, varicocoele, falciform cell anaemia, epididymitis and germ cell tumour. Serum follicle stimulating hormone (FSH) levels were normal or increased while luteinizing hormone (LH) and testosterone levels were normal. Type IV lesion Sertoli cells presented with a de-differentiated appearance. These cells had a small, round euchromatic nucleus with a small nucleolus and vacuolated cytoplasm. The seminiferous tubules were devoid of lumen or ectatic, and the tubular wall was thick and contained abundant elastic fibres. This lesion was characteristic of patients who underwent hormonal treatment because of prostatic carcinoma or sex change. Type V lesion showed abnormally differentiated, probably dysgenetic, Sertoli cells which had a round to ovoid regularly outlined nucleus, with small heterochromatin granules, and the number of these cells was increased. The seminiferous tubules had a central lumen, or were ectatic with vacuolated Sertoli cells, and the amount of elastic fibres was decreased. The most relevant clinical finding in patients with this lesion was orchidopexy. Serum FSH and LH levels were normal or slightly increased. These findings indicate that spermatogonial maturational arrest is associated with a characteristic Sertoli cell morphology that can be easily identified. This morphology may shed light on the aetiology of the disorder, and be useful for establishing the prognosis and bases for treatment in subfertile patients.

Adult↗

PubMed1998

Lectin histochemistry of the human testis.

The oligosaccharide sequences of glycoconjugates and the nature of the saccharide linkage were investigated in normal human testes by means of lectin histochemistry studies, at light and electron microscopy levels. Reaction to WGA was intense in the seminiferous epithelium and interstitium. MAA showed light reactivity in all cell types of the human seminiferous epithelium, the lamina propria and Leydig cells. UEA-I lectin labelled the lamina propria intensely and the seminiferous epithelium and Leydig cells slightly. A slight reaction to AAA was found in the seminiferous epithelium and in Leydig cells. ConA was labelled in Sertoli cells, germ cells and Leydig cells. The reaction to GNA lectin was similar although less intense. PNA labelling was slight in Sertoli cells, spermatogonia, and Leydig cells, and more intense in spermatocytes, spermatids and peritubular cells. Reaction to DSA was intense in the seminiferous epithelium and Leydig cells. HPA labelled all cell types in the seminiferous epithelium and Leydig cells slightly, and labelled peritubular cells intensely. SBA lectin showed a strong reaction in spermatids and a slight reaction in the lamina propria. The reactions to SNA, LTA, and DBA were negative in all testicular cell types. After beta-elimination pre-treatment, MAA, UEA-I, AAA, PNA, DSA, HPA and SBA reactions were all negative. Endo F/PNGase digestion suppressed reactivity to ConA y GNA. Staining for WGA decreased with Endo F/PNGase digestion and also after beta-elimination. Desialization increased reactivity to PNA, SBA and HPA lectins. These results indicate that the terminal sequences of oligosaccharide side-chains in spermatocytes and, principally, in spermatids are: fucose, mannose, Neu5Ac2,3Gal1,3GalNAc, Gal1,3GalNAc, Gal1,4GlcNAc, Neu5AcGalNAc and GalNAc (in O-glycosylated proteins); mannose (in N-glycosylated proteins) and GlcNAc (in both protein types). A sialic acid residue is added to galactose and GalNAc residues. Present findings also indicate that Sertoli cell glycoproteins are similar to those of spermatids, and that the terminal sugar residues in Leydig cells are GlcNAc, fucose, mannose, Neu5Ac2,3Gal1,3GalNAc, Gal1,3GalNAc, and Gal1,4GlcNAc. The lectin pattern of the lamina propria suggests the presence of GlcNAc, galactose, fucose and GalNAc.

Adult↗

PubMed1998

Prevention of peritonitis with disconnect systems in CAPD: a randomized controlled trial. The Mexican Nephrology Collaborative Study Group.

BACKGROUND: Recently, disconnect systems for CAPD that are associated with a reduced frequency of peritonitis have been introduced. Our objective was to compare the incidence of peritonitis using three current CAPD systems in a high-risk population with low educational and socioeconomic levels, and high prevalence of malnutrition. METHODS: In a prospective controlled trial, 147 patients commencing CAPD were randomly assigned to one of three groups: 29 to the conventional, 57 to the Y-set, and 61 to the twin bag systems. The number of peritonitis episodes was registered, and patients were followed up for an average of 11.3 months. RESULTS: The average peritonitis-free interval for the conventional group was 6.1 months, for the Y system was 12.0 months, and for the twin bag was 24.8 months (P < 0.001). By multivariate analysis, the only factor associated with peritonitis was the CAPD system. Peritonitis-related hospitalization was 5.3 +/- 2.0, 2.7 +/- 1.0, and 1.5 +/- 0.9 days/patient/year in the conventional, Y system, and twin bag groups, respectively. The cost per bag was similar for the conventional and Y system, but higher for the twin bag. However, the total costs of treatment (pesos/patient/year) were lower for twin bag (62,159 for the conventional, 70,275 for the Y system, and 54,387 for the twin bag), due to the lower peritonitis incidence and associated hospitalizations. CONCLUSIONS: Y system and twin bag use was associated with a reduction of 50 and 75% peritonitis incidence, respectively, in patients on CAPD. The cost of the twin bag was actually lower, because of savings from a decreased usage of antibiotics and fewer hospitalizations.

Adult↗

PubMed1998

Pre- and post-natal growth of the human ductus epididymidis. A morphometric study.

A histometric study of the development of the human epididymis from the fetal period to adulthood has been carried out in males without testicular or related pathology, distributed into the following groups: (I) fetuses (between the 28th and 37th week of pregnancy); (II) newborns (1-30 days of age); (III) infants (2-4 months of age); (IV) infants (5-12 months of age); (V) infants (1-4 years of age); (VI) children (5-14 years [prepubertal]); and (VII) adults (15-60 years of age). For each age group and each epididymal portion (efferent ducts, caput, corpus and cauda epididymidis) the parameters measured were (1) total surface (epithelium + muscular layer + lumen); (2) the surface occupied by the lumen; (3) the surface occupied by the muscular layer; (4) total diameter of the duct; (5) total diameter of the lumen; and (6) the height of the epithelium. The results of the present study revealed that the development of the efferent ducts and ductus epididymidis follows a biphasic pattern. A progressive development occurs from the fetal period to infants 2-4-months of age. However, this development is transient and regresses during infancy (groups IV and V). At childhood (group VI), a definitive development is initiated and completed at puberty (group VII). These changes seem to be related to the androgen-dependence of the epididymis, the different stages of testicular maturation, and the steroidogenic activity of Leydig cells.

Adolescent↗

PubMed1998

Renal effects of renin-angiotensin system blockade.

Pharmacological interruption of the renin-angiotensin system at different pathway levels has extended our knowledge on the distribution of angiotensin receptors in different nephron segments, its regulation and tubular cell responses. Novel beneficial effects obtained with blockade of this peptide on cellular proliferation and its interaction with other vasoactive systems are particularly important for preventing renal damage.

Angiotensin II↗

PubMed1998

Identification of N- and O-linked oligosaccharides in the human epididymis.

The oligosaccharide sequences of glycoconjugates in the human normal epididymis and the nature of linkages were studied with lectin histochemistry. The usual terminal sequences of oligosaccharide side chains in epithelial cell secretions were Neu5Ac2,3Galbeta1,3GalNAc; SO4Galbeta1,3GalNAc; and Galbeta1,4GlcNAc, and they were mainly found in O-linked glycoproteins. The lectin pattern of mitochondria-rich cells differed from that of principal cells.

Adult↗

PubMed1998

Clinical significance of serum and urine prolactin levels in lupus glomerulonephritis.

UNLABELLED: Prolactin (PRL) has been involved in the pathogenesis of systemic lupus erythematosus (SLE) and hyperprolactinemia has been connected with systemic activity. However, the clinical significance of PRL has not been investigated in lupus glomerulonephritis (GN). METHODS: We studied SLE patients (ACR criteria) with biopsy-proven renal disease. Renal histology was classified according to World Health Organization (WHO) criteria. Renal function tests, albuminuria, complement levels (nephelometry), anti-DNA antibodies (C. luciliae) and serum and urine PRL concentrations (RIA) were determined at baseline and at 4-month intervals for one year. Renal activity was defined as mild, moderate or severe according to serum creatinine, creatinine clearance, albuminuria, red blood cells (RBC), and casts. RESULTS: There were 26 patients with mean age 28.5 y and mean disease duration 47.9 months. Twenty patients had diffuse proliferative glomerulonephritis (GN), four had focal GN and two had membranous GN with proliferative changes. Renal activity was mild in ten patients, moderate in ten and severe in six. Mean serum (24.7+/-5.3) and urine (0.90+/-0.36) PRL levels were higher in patients with severe renal activity (P < 0.05 compared with mild group). PRL levels decreased after treatment, but this trend was not uniform during the follow-up period. CONCLUSION: Hyperprolactinemia was prevalent in SLE patients and high levels of PRL in the serum and urine could be related to severe renal disease.

Adolescent↗

PubMed1998

Transforming growth factor beta 1 and its receptor types I and II. Comparison in human normal prostate, benign prostatic hyperplasia, and prostatic carcinoma.

An immunohistochemical and semiquantitative comparative study of transforming growth factor beta 1 (TGF-beta 1) and its receptor types I (TGF-beta RI) and II (TGF-beta RII) was carried out in normal prostates and in the prostates from men with benign prostatic hyperplasia (BPH), and men with prostatic adenocarcinoma. Immunoreaction to TGF-beta 1 was limited to the basal epithelial cells in the normal prostates. Some cells in the connective tissue stroma were also stained. In BPH immunolabelling was also observed in columnar (secretory) cells of the epithelium. In prostatic adenocarcinoma, all epithelial cell types were intensely immunostained. Some stromal cells were also stained. Immunostaining to TGF-beta RI was only present in the basal cells in normal prostates. In BPH, this immunoreaction was found in the whole epithelium and in some stromal cells. In prostatic cancer, the immunostaining pattern for this receptor was similar to that of BPH but more intense in the epithelial cells. Immunoreactivity to TGF-beta RII appeared in some basal cells and some scattered columnar cells of the normal prostate epithelium. In the BPH sections, this pattern was maintained, and a weak immunolabelling was also observed in the stroma. In prostate cancer, all epithelial cells appeared intensely labelled. In the stroma, immunolabelling was similar to that of the BPH specimens. The results of the present study suggest that, in normal prostates, only the basal cells of the epithelium possess both receptor types, and hence can transduce TGF-beta 1 signal intracellularly. The basal cells can also secrete this growth factor which would act as an autocrine inhibitory growth factor for them. In addition, TGF-beta 1 is secreted in some zones by stromal cells, acting then as a paracrine growth factor for basal cells in those areas. In BPH, in addition to the basal cells, some secretory columnar cells also secrete TGF-beta 1 and possess both types of TGF-beta 1 receptors, and thus, both epithelial cell types are susceptible to TGF-beta 1 action. Since both receptor types are also present in some stromal cells, these cells also perform an autocrine secretion, in addition to their paracrine secretion to the epithelial cells. TGF-beta RIIs seem to be more numerous than TGF-beta RIs and this lead us to hypothesize that these incomplete receptors might be a protection against the inhibition caused by TGF-beta 1 action. In prostatic carcinoma all cell types display the same characteristics as in BPH, although both receptor types are found in similar numbers, and thus, the above mentioned protection would not occur.

Adenocarcinoma↗

PubMed1997

Immunocytochemical and quantitative study of the tunica albuginea testis in young and ageing men.

A light and electron microscope immunohistochemical study of the tunica albuginea from both young and elderly men was carried out to determine the distribution of the cells that contain actin, vimentin and/or desmin, and to evaluate the possible variations with ageing by means of quantitative studies. Testicular volume and testicular parenchyma volume decreased significantly with age whereas the tunica albuginea volume remained unchanged. These results agree with the scanty quantitative changes observed in the testicular connective tissue with age, and the notion that age-related changes in testicular volume are principally restricted to the seminiferous tubules. Three connective tissue layers could be distinguished in the tunica albuginea in both young and elderly men. The middle and inner layers increased in width with age while the width of the outer layer decreased. The average width of the tunica albuginea increased significantly with ageing. The tunica albuginea of young men and elderly men presented two types of fusiform cells: (1) fibroblast-like cells, which immunoreacted to actin and vimentin, but not to desmin; and (2) myoid cells, which immunoreacted to actin, vimentin and desmin. In both young men and elderly men, the total number of desmin-positive cells (myoid cells) was significantly lower than that of fibroblasts. However, the total number of desmin-positive cells was significantly increased in ageing men. In young testes, desmin-positive cells were more abundant in the outer layer of the tunica albuginea, whereas in elderly men these cells predominated in the middle layer. The increased desmin immunoexpression in the tunica albuginea of ageing men contrasts with the decrease in desmin immunoreaction in other myoid cells of the testis, the peritubular myoid cells, but only in seminiferous tubules that showed severe germ cell depletion. This suggests that changes in intermediate filament immunoexpression in peritubular cells are focalised, and thus, under local control, whereas changes in the tunica albuginea cells are generalised and possibly related to factors also affecting the connective tissue in other organs.

Actins↗

PubMed1997

Intermediate filaments in the Sertoli cells of the ageing human testis.

The presence and distribution of intermediate filaments (vimentin, keratin, desmin) was studied in the Sertoli cells of elderly men by means of quantitative immunohistochemical methods. Sertoli cells from young men showed moderate immunogold labelling to vimentin throughout the entire cytoplasm between the cell organelles in tubules showing complete spermatogenesis. Immunogold particles were more numerous in the perinuclear cytoplasm and beneath the plasma membrane in all its faces. The testes from elderly men showed different tubule types; some showed complete spermatogenesis and a normal lamina propria, while others had spermatogenic arrest at different levels (spermatids, spermatocytes, spermatogonia). The immunohistochemical reaction to vimentin in the Sertoli cells of tubules with complete spermatogenesis (type a) was similar to that in the cells of young men. In the Sertoli cells of severely damaged tubules (type b) the immunohistochemical reaction was more intense and immunogold particles extended in similar proportions throughout the whole cytoplasm. When immunolabelling intensity was compared between the three groups of tubules, by counting the number of immunogold particles per square micrometre of cytoplasm, it was found to be significantly higher (P < or = 0.05) in type b tubules of elderly men than either in tubules of young men or in type a tubules of elderly men. Since the average cell surface of Sertoli cells was similar in all tubule types, these data suggest that an actual vimentin increase occurs in Sertoli cells of germ-cell-depleted tubules. Sertoli cell immunogold labelling to keratin was found neither in young men nor in type a tubules of ageing men, whereas a positive immunohistochemical reaction was observed in the Sertoli cells of type b tubules of elderly men. Immunogold particles were localized mainly in the perinuclear cytoplasm, and beneath the lateral and basal cell surfaces. The observation of vimentin increase and keratin re-expression in ageing Sertoli cells only in germ-cell-depleted tubules suggests that the changes in intermediate filaments are related to the local factors associated with completion of spermatogenesis, causing functional changes in Sertoli cells.

Adult↗

PubMed1997

Effect of aprotinin on vascular reactivity of coronary bypass grafts.

OBJECTIVE: Aprotinin reduces postoperative bleeding and the need for transfusion after cardiopulmonary bypass. The current clinical concern about aprotinin is that it may increase the incidence of postoperative graft thrombosis and thromboembolic phenomena. The fact that the mechanism of action of aprotinin is not completely elucidated and that its effects on the vascular reactivity of bypass conduits are unknown raise doubts regarding its safety. In an attempt to clarify these issues we investigated the vascular reactivity of the human saphenous vein and internal thoracic artery to a range of vasoconstrictor agents in the presence or absence of aprotinin. METHODS: Human saphenous vein was obtained from 24 patients and internal thoracic artery from 7 patients undergoing coronary artery bypass. Vessels were set up in organ baths to record changes in vessel wall tension. RESULTS: Endothelium-dependent relaxations to acetylcholine in saphenous vein rings were unaffected after aprotinin treatment. Contractions to the thromboxane analog U46619 were significantly attenuated after aprotinin treatment in the saphenous vein. Maximum responses were reduced from control values of 88 +/- 7.5 mN to 49.3 +/- 4.8 mN with 1 mumol/L doses of aprotinin (p < 0.05) and 36.6 +/- 4.8 mN with 10 mumol/L doses of 5-hyroxytryptamine or noradrenaline after aprotinin incubations. Furthermore, contractions to U46619 in the internal thoracic artery were unaffected by aprotinin. CONCLUSION: Our data show that there is a preservation of endothelium-dependent responses to acetylcholine and a reduced U46619 vasoconstrictor action on the saphenous vein after aprotinin treatment. Thus the direct effect of aprotinin on the vessel wall could counteract the potential effect of its prothrombotic action on graft patency.

Acetylcholine↗