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Biomedical subjects

R Paniagua

Publications and source records attributed to R Paniagua.

At least 235 records · Page 13Linked to original sources
PubMed1977

Effects of physical training on rat myocardium. An enzymatic and ultrastructural morphometric study.

Rats subjected to physical training through swimming increased their weight at a slower rate than controls, which initially had the same characteristics. The ratio heart weight/body weight was 23% greater in the trained rats. However, the absolute weights of the hearts were only 7% greater. The ultrastructural morphometric study, backed up by and analysis of the hierarchical variance, did not reveal significant changes neither in the myofibrillar and mitochondrial volume nor in the number of mitochondria per surface unit of myocardium. Furthermore, no variations were recorded, due to training, in the amount of mitochondrial protein nor in the specific mitochondrial activities of malate dehydrogenase, cytochrome c oxidase and ATPase. It is therefore suggested that the increase in the measured parameters, due to training, is proportional to the increase in weight and size of the heart. On the other hand, the specific activity of LDH increased by 15% after the first weeks of training.

Adenosine Triphosphate↗
PubMed1976

A special pattern of the smooth endoplasmic reticulum in the kidney of the snail Cryptomphalus aspersa.

A special structural pattern of the smooth endoplasmic reticulum (SER) has been observed in the kidney of the snail Cryptomphalus aspersa. Two types of cells (clear and dark) cover the foldings of the renal sac; the dark cells are by far the most numerous. A cisterna of SER enveloping the nucleus appears invariably in both types of cells, with no disruptions, or small ones (from 50 to 90 nm) along its profile. The layer of cytoplasm lodged between the external nuclear membrane and this cisterna is found invariably to be from 0-20 to 0-25 mum in width. Glycogen is abundant in the cytoplasm as alpha particles, and also in the nucleus, but as beta particles. It is noteworthy that absolutely no glycogen is present in the layer of cytoplasm lodged between the nuclear membrane and the surrounding SER envelope. Long profiles of SER are also observed closely approaching and parallel to the plasma membrane of the dark cells. Considering the role of SER in glycogen metabolism in the kidney of the snail, the possible function of these cisternae as a support system ofr enzymes involved in the metabolism of glucides is discussed.

Animals↗
PubMedDate not supplied

Seminiferous tubule degeneration in human cryptorchid testes.

Two types of degenerating seminiferous tubules were found in cryptorchid testes with Sertoli cell hyperplasia of children and adults: 1) tubules with central degeneration, and 2) tubules with total degeneration. Central degeneration begins with degenerative changes in germ cells that accumulate in the lumen of the seminiferous tubule. Some Sertoli cells may also be affected. Degenerated cells finally disappear, and the remaining tubule is composed of only a cuboidal epithelium, which consists mainly of Sertoli cells and occasional germ cells surrounding a wide lumen. Total degeneration is principally seen in tubules with severe germinal hypoplasia. All the seminiferous epithelium cells degenerate and lose their characteristic distribution, forming a disorganized Sertoli cell nodule surrounded by a thickened basement membrane. Lastly, Sertoli cells disintegrate, and the seminiferous epithelium disappears. Tubular degeneration might be related to the thickening of the basement membrane, which hinders metabolic interchange between the seminiferous epithelium and the interstitium.

Adolescent↗
PubMedDate not supplied

Effects of neonatal estrogen administration on rat testis development with particular reference to Sertoli cells.

An ultrastructural and morphometric study of the testes in 15-, 22-, 45-, and 90-day-old neonatally estrogenized rats was performed. At 45 days of age, the Sertoli cells appeared immature in estrogenized rats, whereas they were fully mature in the controls. This finding might be related to a deficiency in gonadotropins and androgens during the postnatal period. In 90-day-old estrogenized rats, however, Sertoli cell maturation had occurred, which might be attributed to a recovery of hormone levels. Cytoplasmic alterations, however, such as vacuolation, were present at this age. The morphometric study revealed decreased testicular and tubular volumes as well as decreased mean tubular diameters in the estrogenized animals. In contrast, the absolute tubular length increased more in these animals than in the controls during the period from 15 to 90 days of age. This lengthening process might be related to the large number of hypercurved tubules in the estrogenized rats.

Age Factors↗
PubMedDate not supplied

Decrease in the number of human Ap and Ad spermatogonia and in the Ap/ Ad ratio with advancing age. New data on the spermatogonial stem cell.

The numbers of Ap and Ad spermatogonia per unit section of the testis were calculated in autopsy specimens from young adults and elderly men without testicular pathology. The number of Ap spermatogonia decreased from the 6th decade of life, whereas that of Ad spermatogonia began to decrease in the 8th decade. Although it has been reported that Ad spermatogonia are more sensitive to noxious agents than Ap spermatogonia, the involution of Ap spermatogonia precedes that of Ad spermatogonia. These findings provide new information on concepts relating to the spermatogonia precedes that of Ad spermatogonia. These findings provide new information on concepts relating to the spermatogonial stem cell in man.

Adult↗
PubMedDate not supplied

Diverticula of human seminiferous tubules in the normal and pathologic testis.

The occurrence of diverticula in human seminiferous tubules was investigated in the adult human testis in normal as well as physiologic (aging) and pathologic (germ cell depletion, obstruction of male excretory ducts, varicocele and systemic arteriosclerosis) conditions. Diverticula, which are evaginations of the seminiferous epithelium surrounded by a thin tunica propria, were present in all groups studied. The number of diverticula per mm2 testis was higher in the testis with obstruction than in those without obstruction at each age considered. The number of diverticula increased with age in both the obstructed and nonobstructed testis. No changes in the number of diverticula per mm2 testis were found in relation to systemic arteriosclerosis or different degrees of germ cell depletion. Varicocele was only associated with increased numbers of diverticula when it was also associated with obstruction. The formation of diverticula in human seminiferous tubules seems to be an obstructive process related to increasing age.

Adult↗
PubMedDate not supplied

Cola beverage consumption induces bone mineralization reduction in ovariectomized rats.

BACKGROUND: A significant association of cola beverage consumption and increased risk of bone fractures has been recently reported. The present study was carried out to examine the relationship of cola soft drink intake and bone mineral density in ovariectomized rats. METHODS: Study 1. Four groups of 10 female Sprague-Dawley rats were studied. Animals from groups II, III, and IV were bilaterally ovariectomized. Animals from groups I and II received tap water for drinking, while animals from groups III and IV each drank a different commercial brand of cola soft drink. After 2 months on these diets, the following were measured: solid diet and liquid consumption; bone mineral density; calcium in bone ashes; femoral cortex width; calcium; phosphate; albumin; creatinine; alkaline phosphatase; 25-OH hydroxyvitamin D, and PTH. RESULTS: Study 2. Two groups of seven ovariectomized rats were compared. Group A animals received the same management as the group III animals from study 1 (cola soft drink and rat chow ad libitum), while rats from group B received tap water for drinking and pair-feeding. After 2 months plasmatic ionized calcium, phosphate, creatinine, albumin, calcium in femoral ashes, and femoral cortex width were measured. Study 1. Rats consuming cola beverages (groups III and IV) had a threefold higher liquid intake than rats consuming water (groups I and II). Daily solid food intake of rats consuming cola soft drinks was one-half that of rats consuming water. Rats consuming soft drinks developed hypocalcemia and their femoral mineral density measured by DEXA was significantly lower than control animals as follows: group I, 0.20 +/- 0.02; group II, 0.18 +/- 0.01; group III, 0.16 +/- 0.01, and group IV, 0.16 +/- 0.01 g/cm(2). Study 2. To rule out the possibility that these calcium and bone mineral disorders were caused by decreased solid food intake, a pair-fed group was studied. Despite a lower body weight, pair-fed animals consuming tap water did not develop bone mineral reduction or hypocalcemia. CONCLUSIONS: These data suggest that heavy intake of cola soft drinks has the potential of reducing femoral mineral density.

Albumins↗
PubMedDate not supplied

Response of atrial natriuretic factor to acute extracellular fluid volume in patients with pheochromocytoma.

BACKGROUND: Patients with pheochromocytoma have been reported to show high plasmatic atrial natriuretic factor (ANF) levels. Its source may not be the atrium because blood volume, the most important physiological stimulus for ANF release, is usually reduced in these patients. METHODS: To evaluate ANF secretion functional integrity, we studied three patients with pheochromocytoma before and after surgical removal of the tumor. Extracellular fluid (ECF) volume, plasmatic ANF levels, and plasmatic renin activity (PRA) were measured. ANF was measured before and after an acute saline load of 1.5L in 90 min. RESULTS: Before surgery, ECF volume was normal or reduced, and PRA was normal but decreased after the saline load. By contrast, ANF was elevated and did not change after the saline load. After surgery ANF decreased, ECF volume rose, and the saline load induced a significant increase of plasma ANF and reduction of PRA. ANF was present in significant amounts in tumoral tissue homogenates. CONCLUSIONS: These data suggest that the tumor was the source of ANF in these patients with pheochromocytoma because high levels of ANF, despite reduced or normal ECF volume, as well as unresponsiveness to acute saline infusion, were found before surgery with subsequent normalization after tumor removal.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

Leydig cell differentiation induced by stimulation with HCG and HMG in two patients affected with hypogonadotropic hypogonadism.

In order to elucidate the ultrastructural characteristics of the precursor cell of Leydig cells and its subsequent differentiation, testicular biopsies from two patients with hypogonadotropic hypogonadism, obtained prior to and after treatment with HCG and HMG, were studied in comparison with those of prepubertal, pubertal and postpubertal testes. Prior to HCG and HMG stimulation, the testicular interstitium of both patients showed the following spindle-cell-types: Fibroblasts, myofibroblasts and a cell-type similar to the myofibroblast but differing from it by the arrangement of microfilaments and the development of the smooth endoplasmic reticulum as well as lipid droplets. It may be considered the precursor of Leydig cells. In the following stages of differentiation observed in the biopsies after treatment, there is a progressive involution of microfilaments and rough endoplasmic reticulum, a transient period of hyperplasia of the Golgi complex, and the definitive development of cell components involved in steroid biosynthesis, such as the smooth endoplasmic reticulum, polymorphic mitochondria with tubular cristae, lipid droplets and diverse lysosomal bodies. From early stages of differentiation, gap junctions occurred between the cells. Numerous axon profiles were also present among the cells. Only in a small percentage of cells did vesicle-bearing axons closely appose the Leydig cell membrane.

Adult↗
PubMedDate not supplied

47,XXY Klinefelter's syndrome with low FSH and LH levels and absence of Leydig cells.

Examination of testicular biopsy from a patient with 47,XXY Klinefelter's syndrome revealed a diffuse hyalinization of seminiferous tubules as well as absence of mature Leydig cells. Ultrastructural findings showed some immature Leydig cells in the testicular interstitium. Hormone assays revealed low serum FSH and LH levels. The association of both, hormone assays and testicular morphologic pattern, suggests the presence of a Klinefelter's syndrome with hypogonadotropic hypogonadism.

Adult↗
PubMedDate not supplied

Multi-vacuolated leydig cells in human adult cryptorchid testes.

A histological study of 23 testicular biopsies or surgical specimens from adult cryptorchid testes revealed the presence of multi-vacuolated Leydig cells in 12 cases. These cells showed abundant lipid inclusions and scarce secondary lysosomes as well as liprofuchsin pigment granules. Some of these cells contained crystals of Reinke but others had only microcristalline inclusions. This Leydig cell alteration may be related either to heat or to congenital lesions.

Adolescent↗
PubMedDate not supplied

Testicular biopsy and hormonal study in a male with Noonan's syndrome.

The testicular biopsy study of a 17-year-old male with Noonan's syndrome revealed seminiferous tubules of reduced diameter with hypospermatogenesis. Many spermatocytes underwent degeneration and many spermatids developed abnormal. The Sertoli cells were similar to immature Sertoli cells. Fully differentiated Leydig cells were rare while precursor Leydig cells were numerous. Both gonadotropin and testosterone levels were low, and a lack of response to LH-RH as well as to clomiphene was found. The testicular biopsy performed at 20 years of age revealed a certain maturation of the seminiferous tubules which increased the germ cell number. The abnormalities in the spermatogenesis as well as the immature appearance of Sertoli cells continued. Leydig cells were more numerous and showed a certain development without reaching the normal pattern. Gonadotropin levels were normal while testosterone levels low. The response to LH-RH was increased and the absence of response to clomiphene persisted. These features suggest a delayed puberty.

Adult↗
PubMedDate not supplied

Occurrence of primary spermatocytes in the infant and child testis.

Light microscope and ultrastructural studies of normal infants and children testes revealed the presence of primary spermatocytes and occasional spermatids at 4, 8, 9, 11, 12 and 13 years of age, but not in all the boys of these ages. When they were found they appeared in both testes, but only in a 5-25% of the seminiferous tubules. These spermatocytes undergo degeneration or progress to abnormal spermatids which degenerate in turn. Spermatozoa were never found.

Adolescent↗
PubMedDate not supplied

Multinucleate Leydig cells in normal human testes.

The number of mononucleate and multinucleate Leydig cells per unit area of the testis was determined in normal adult men using the peroxidase-anti-peroxidase method for testosterone detection. The results of this study indicate that the number of multinucleate Leydig cells increases markedly with age, whereas the total Leydig cell population decreases.

Adult↗
PubMedDate not supplied

Ciliated cells in the rat testis effects of neonatal administration of estrogens.

The presence of cells bearing solitary cilia has been studied in the testes of normal and neonatally estrogenized rats. Peritubular myoid cells and undifferentiated interstitial cells showed a higher frequency of cilia in estrogenized animals than in control ones, from 15 to 45 days of age, the differences being slighter at 90 days of age.

Animals↗
PubMedDate not supplied

Multinucleate epithelial cells in the ductuli efferentes of human epididymis.

The histological and ultrastructural study of the ductuli efferentes in epididymides from 40 adult men revealed the occurrence of multinucleate epithelial cells in all specimens. These cells appeared in the luminal protrusions of epithelial folds and correspond to either principal or ciliated cells. The ultrastructure of their cytoplasm did not differ from that of their respective mononucleate cells. Multinucleate cells contained 3-20 closely juxtaposed nuclei, thus appearing much more irregularly outlined than those of the mononucleate epithelial cells. Multinucleation four times more frequent in the principal cells than in the ciliated cells. The number of multinucleate cells increased progressively from the age of 60 years onwards. The average number of nuclei per cell increased in the fourth decade of life, was maintained up to the eighth decade, and then increased again.

Adolescent↗
PubMedDate not supplied

Significance of DNA quantification in testicular germ cell tumors.

A cytophotometric quantification of DNA in tumor cells was performed in histological sections of orchidectomy specimens from 36 men with testicular germ cell tumors (TGCT), 7 of them showing more than one tumor type. Among the variants of seminoma (classic and spermatocytic) the lowest DNA content were in spermatocytic seminoma. With respect to non-seminomatous tumors (yolk sac tumor, embryonal carcinoma, teratoma, and choriocarcinoma), choriocarcinomas showed the highest DNA content, and the lowest value was found in teratomas. No significant differences were found between the average DNA content of seminomas (all types) and non-seminomatous tumors (all types). Both embryonal carcinoma and yolk sac tumor showed similar DNA content when they were the sole tumor and when they were found associated with other tumors. In this study, except for the 4 cases of teratoma and the case of spermatocytic seminoma, all TGCT examined did not show modal values of DNA content in the diploid range. Such an elevated frequency of aneuploidism in these tumors may be helpful for their diagnosis.

Adult↗