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Biomedical subjects

R Paniagua

Publications and source records attributed to R Paniagua.

At least 163 records · Page 9Linked to original sources
PubMed1987

Presence of basic proteins and ribonucleoproteins in the neck region of human spermatids and spermatozoa.

The ultrastructural cytochemical study of the neck region of human spermatids and spermatozoa revealed that, besides the centrioles, the basal plate, the lateral cupshaped junction body and the annulus material showed affinity for both ethylene diamine tetra-acetic acid (EDTA) stain (a preferential staining method for ribonucleoproteins) and ethanolic phosphotungstic acid (PTA) stain (for cellular localisation of basic proteins). The capitulum and the surface of the striated columns were also stained with ethanolic PTA. The chromatoid body and annulate lamellae-which were frequently encountered in the neck region--stained with both EDTA and ethanolic PTA techniques. This suggests a possible participation of the chromatoid body and annulate lamellae in the formation of the neck region structures.

Adult↗
PubMed1987

Correlation study between prolactin and androgens in male patients with systemic lupus erythematosus.

The hypothalamic-pituitary-gonadal axis was studied in 8 male patients with systemic lupus erythematosus (SLE), both before and after intravenous administration of luteinizing hormone-releasing hormone (LH-RH). We provide evidence herein that resting serum levels of estrone are increased and that resting serum testosterone (T) and dihydrotestosterone (DHT) levels are decreased in male patients with SLE. The decreased serum T levels were observed even after the IV administration of 25 micrograms of LH-RH. The high basal serum prolactin (PRL) levels observed in these patients with SLE is a novel finding not previously reported that could explain why serum T and DHT levels are low in this syndrome. We observed a decrease in the pituitary response to LH-RH stimulation; this low response could also be a hormonal manifestation of hyperprolactinemia. Furthermore, it has been suggested that PRL plays a role in immunocompetence, and therefore it could have influence either directly or indirectly in the altered immunoregulation observed in SLE.

Adult↗
PubMed1986

A quantitative morphological study of human Leydig cells from birth to adulthood.

Human testicular specimens were obtained from biopsies and autopsies covering the period from birth to adulthood. The number of testosterone-containing Leydig cells was determined using the peroxidase-anti-peroxidase method. This number decreased markedly from 3-6 months of age to the end of the first year of life and, up to 6 years of age, only a small number of testosterone-containing cells was found. From 6 years onwards the number of Leydig cells progressively increased. Ultrastructural examination revealed four types of Leydig cells: fetal-type Leydig cells (from birth to 1 year of age) with round nuclei, abundant smooth endoplasmic reticulum and mitochondria with tubular cristae; infantile-type Leydig cells (from birth to 8-10 years of age), showing a multilobated nucleus, moderately abundant smooth endoplasmic reticulum, some lipid droplets and mitochondria with parallel cristae; prepubertal, partially differentiated Leydig cells (from 6 years of age onwards) with regularly-outlined round nuclei, abundant smooth endoplasmic reticulum, mitochondria with tubular cristae, and some lipid droplets and lipofuscin granules; and mature adult Leydig cells (from 8-10 years of age onwards). The ultrastructure of the infantile-type Leydig cells and the lack of delay between the disappearance of the fetal-type Leydig cells and the appearance of infantile-type Leydig cells suggest that fetal-type Leydig cells give rise to the infantile-type Leydig cells. Before puberty, myofibroblast-like precursor cells differentiate into the prepubertal, partially differentiated Leydig cells, which complete their differentiation into the adult Leydig cells.

Adolescent↗
PubMed1986

Mitosis in adult human Leydig cells.

The ultrastructural study of testicular biopsies from 87 adult men revealed mitosis in two mature Leydig cells, each from a different man. The men showed normal hormone levels and had received no previous chemotherapy or hormone treatment, nor had they been exposed to known toxic agents. The presence of mitotic Leydig cells suggests that differentiated Leydig cells may divide and contribute either to the increase in the number of Leydig cells or to the formation of multinucleate Leydig cells.

Adult↗
PubMed1986

Ultrastructural observations on nucleoli and related structures during human spermatogenesis.

The ultrastructural study of nucleoli and ribonucleoprotein-containing structures in human seminiferous tubules revealed that the nucleoli of spermatogonia, spermatocytes and Sertoli cells exhibited a tripartite structure consisting of: a fibrillar center, a compact granular portion, and a reticular portion containing both pars fibrosa and pars granulosa. The nucleoli of primary spermatocytes showed a developed reticular portion. At pachytene, the compact granular portion enlarged and lost its connection with the fibrillar center and the reticular portion which decreased in size. This suggests a nucleolar segregation similar to that of ovocytes in many species. Two similar developmental stages of nucleoli were observed in spermatogonia. In addition to nucleoli, there were other ribonucleoprotein-containing structures such as intranuclear closely-packed granules in Ap spermatogonia, coarse granules in the chromatin rarefaction zone of Ad spermatogonia, the nuage and Lubarsch crystals of spermatogonia, the chromatoid body of spermatids, the annulate lamellae of both spermatids and Sertoli cells, and many structures of the spermatid neck region.

Adult↗
PubMed1986

Diverticula of the ductus epididymis in men.

The histological study of epididymides obtained from autopsies (41 children, 7 young adults and 8 elderly men) and surgical specimens (10 young adults and 3 elderly men) revealed the presence of multiple diverticula in the cauda epididymis in all elderly men and in only 2 young adults (32 and 33 years old). The diverticula appeared as evaginations of the epithelial lining of the duct, disrupting the muscular coat and expanding into the surrounding connective tissue. The formation of epididymal diverticula seems to be an age-related process that might be caused by repeated increases in the intraluminal pressure in the cauda epididymis.

Adolescent↗
PubMed1986

Postsurgical focal testicular infarct.

A 74-year-old man was surgically treated owing to incarcerated right inguinal hernia. Following surgery, he developed a focal hemorrhagic testicular infarct localized in the anterior pole of the right testis. The cause of the infarct seemed to bei either thrombosis or compression by edema of the veins draining the testis.

Aged↗
PubMed1986

Idiopathic peritesticular fibrosis associated with retroperitoneal fibrosis.

A 32-year-old male who presented with idiopathic retroperitoneal fibrosis developed peritesticular fibrosis 4 years later. The lesion appeared as a diffuse, uniform thickening without a tendency to form nodules. Histologic examination revealed a densely collagenized tissue with scattered cells, consisting mainly of fibroblasts and plasma cells. Small blood and lymphatic vessels of the tumor showed luminal dilation and perivascular edema with inflammatory infiltrates. No other associated pathology was found in the patient. We suggest that peritesticular fibrosis in this patient may be due to lymphatic drainage obstruction caused by retroperitoneal fibrosis.

Adult↗
PubMed1986

Quantitative differences between variants of A spermatogonia in man.

The area of cytoplasm, nucleus, nucleolus and mitochondria, as well as the elongation and irregular outline of the nucleus were determined, on electron micrographs by using an image analyser, for Ap (pale), Ad (dark with intranuclear vacuole), Ad-like (dark without intranuclear vacuole), Ac (cloudy) and Al (long) human spermatogonia. Ap and Ac spermatogonia had larger nucleus, larger nucleolus, and more cytoplasm than did Ad, Ad-like, and Al spermatogonia. In addition, the nuclei of Ap and Ac spermatogonia were more spherical and had a more distinct outline.

Adult↗
PubMed1986

Multinucleate spermatids in aging human testes.

A comparative morphologic study between the testes of 25 young adult men and 41 elderly men without testicular or related pathological conditions revealed the presence of multinucleate spermatids, showing up to 86 nuclei, in the testes of 3 of the elderly men. The formation of multinucleate spermatids is probably due to cell fusion, since the number of nuclei in these cells is not always 2n and multinucleate spermatocytes were uncommon. This anomaly seems to be another manifestation of an involutive process that also affects other cell types in the aging testis.

Acrosome↗
PubMed1986

Low plasma zinc and androgen in insulin-dependent diabetes mellitus.

Plasma zinc and pituitary and testicular hormone concentrations were measured in two groups of male adolescents. One group comprised insulin-dependent diabetes mellitus patients, aged 14-19 years; the other, as control, included 12 healthy youngsters aged 13-19 years. Plasma concentration of zinc, prolactin, testosterone, and dihydrotestosterone were lower in diabetics than in controls, whereas the ratios of androstenedione and androstenedione to testosterone + dihydrotestosterone were higher. Plasma FSH and LH were normal. These results suggest a diminished conversion of androstenedione to testosterone and relate zinc with the 17-beta-hydroxysteroid dehydrogenase enzyme activity.

Adolescent↗
PubMed1986

Increased number of mast cells in the testis of neonatally estrogenized rats.

The presence of increased numbers of mast cells in the testis of adult neonatally estrogenized rats is reported. The histometric study revealed significant differences between control and estrogenized animals for two ages considered (45 and 90 days). This increase might be related with the development of connective tissue in estrogenized rats.

Animals↗
PubMed1986

Changes in the connective tissue and decrease in the number of mast cells in the testes of men with alcoholic and non-alcoholic cirrhosis.

The testicular connective tissue of patients with alcoholic and non-alcoholic cirrhosis was studied by Picrosirius staining for collagen fibres and electron microscopy, and then compared with the connective tissue of normal testes. Under polarized light, the interstitial connective tissue in the testes of patients with alcoholic and non-alcoholic cirrhosis exhibited a green birefringence which did not appear in normal testes, and the orange birefringence characteristic of the tunica propria in the testes of both cirrhotic and normal males was less developed in cirrhosis. This suggests that a connective tissue, consisting of smaller and less ordered collagen fibre bundles than those in the tunica propria is formed in the testicular interstitium of cirrhotic males, and the collagen fibre bundles of the tunica propria are less developed than in normal testes. The appearance of connective tissue was associated with a decrease in the number of mast cells in the testes of cirrhotic males suggesting the involvement of mast cells in the synthesis, packing, and organization of collagen fibres. The cause of the decrease in mast cell numbers may be related to hormone alterations, in particular testosterone deficiency.

Adult↗
PubMed1986

Morphometric aspects of rat testis development.

A morphometric study of rat testis development and ageing (from 5 to 360 days of age) has been carried out. The testicular volume increases from 10.28 +/- 0.35 mm3 (5 days of age) to 1819.43 +/- 52.67 mm3 (360 days of age), showing the most rapid increase between 20 and 70 days of age (22.6 times). The mean tubular diameter increases from 62.25 +/- 1.50 micron (5 days of age) to 280.81 +/- 9.77 microns (360 days of age) and the tubular length from 2.74 +/- 0.18 m (5 days of age) to 25.45 +/- 1.76 m (360 days of age). Up to 15 days of age, the increase in testicular volume was mainly due to the increase in tubular length, whereas from this age onwards the tubular growth was similar in both length and diameter. Tubular development had nearly finished at 70 days of age.

Aging↗
PubMed1986

Ultrastructure of Leydig cells in human ageing testes.

Ultrastructural study of Leydig cells in elderly men revealed the following Leydig cell types: (1) ultrastructurally normal Leydig cells (46.2%); (2) Leydig cells either with multiple cytoplasmic or intranuclear Reinke crystals or with numerous para-crystalline inclusions (6.1%); (3) multivacuolated Leydig cells with the cytoplasm almost filled by lipid droplets (16.7%; (4) dedifferentiated Leydig cells with poor development of agranular endoplasmic reticulum and mitochondria, and increased amounts of lipofuscin granules (22.3%); and (5) bi- or trinucleate Leydig cells (8.7%) showing either a normal (2.8%) or dedifferentiated (5.9%) cytoplasm. These results suggest an involution of Leydig cells with advancing age. A correlation between the proportion of altered Leydig cells and the decrease in testosterone and increase in luteinising hormone levels could be observed.

Adult↗
PubMed1985

Quantitative and ultrastructural study of Leydig cells in Klinefelter's syndrome.

This ultrastructural and quantitative study of Leydig cells in Klinefelter's syndrome has been performed using the entire testes obtained from four autopsies plus testicular biopsies from 20 patients. The total Leydig cell volume per testis in Klinefelter's syndrome was similar to that of control testes. However, the total number of Leydig cells per testis was significantly lower in the patients with Klinefelter's syndrome than in the controls. This may be attributed to the Leydig cell hypertrophy that these patients underwent. In patients with Klinefelter's syndrome the average volume of each Leydig cell was significantly higher than that of the controls. Electron microscopic findings revealed that besides ultrastructurally normal Leydig cells there were three other morphologically abnormal Leydig cell types: abnormally differentiated cells; multivacuolated cells; and immature Leydig cells. The ultrastructurally normal Leydig cells were probably the cells principally responsible for testosterone biosynthesis in these patients, whereas the other Leydig cell types were probably barely or not at all functional. The hypertrophy showed by the ultrastructurally normal Leydig cells may be interpreted as an attempt to increase testosterone production.

Adult↗
PubMed1985

Changes in young rat radius following excision of the perichondrial ring.

The distal growth plate of the radius was exposed in young rats and the perichondrial ring and fibrous covers were removed at the exposed surface. In addition, a small portion of either the adjacent epiphysis or of the adjacent metaphysis was removed also. In the following days, important alterations in bone structure were observed at the level of the removed perichondrial ring. The most relevant changes were an enlargement of the growth plate at the exposed surface that grew in an abnormal direction, proliferation of bone trabeculae at the level of the excised perichondrial ring, and bending of the bone. No regeneration of the perichondrial ring occurred. These changes support both the role of the perichondrial ring in the mechanical constraint of the growth plate, and the induction of bone formation by the hypertrophic cartilage at the level of the absent perichondrial ring.

Animals↗