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Biomedical subjects

R Paniagua

Publications and source records attributed to R Paniagua.

At least 217 records · Page 12Linked to original sources
PubMed1980

Histologic classification of undescended testes.

On the basis of testicular biopsy study in 203 patients and study of a second biopsy specimen from 27 of these patients, prepubertal undescended testes were classified into four categories according to the mean tubular diameter, the tubular fertility index, and the Sertoli cell index. Type I cases (testes with minimal lesions) were characterized by a normal mean tubular diameter and normal tubular fertility and Sertoli cell indexes or slight tubular hypoplasia. This group represented 26 per cent of the undescended testes. The corresponding lesions can be observed from two years of age onward and are probably acquired. After puberty normal spermatogenesis occurs. Type II cases (24 per cent of the undescended testes) included testes with marked germinal hypoplasia as well as slight or marked tubular hypoplasia and a normal Sertoli cell index. After puberty these testes develop a degree of marked hypospermatogenesis, maturation arrest, or Sertoli cells with only isolated spermatogonia and primary spermatocytes. In type III cases (testes with diffuse tubular hypoplasia) the mean tubular diameter and the tubular fertility and Sertoli cell index values were severely reduced. This group represented 33 per cent of the undescended testes, and after puberty most of them showed seminiferous tubules with exclusively adult Sertoli cells. Type IV testes (diffuse Sertoli cell hyperplasia) were associated with a nearly normal mean tubular diameter and variable tubular fertility index values and represented 17 per cent of all the undescended testes. After puberty Sertoli cells do not mature completely, and therefore in spite of the earlier tubular fertility index, the germinal cell line does not reach adult development. Although early orchiopexy prevents tubular fertility index and mean tubular diameter deterioration due to the noxious effects of temperature in type I testes, we believe that there is no such benefit in the other types. These patients may present only slight modifications in these indexes.

Adolescent↗
PubMed1980

Development of the endoplasmic reticulum during human spermatogenesis.

Human primary spermatocytes show a special development of the endoplasmic reticulum (ER). During the leptotene-zygotene stages a cisterna of ER surrounds a third or half of the nucleus closely associated with the nuclear envelope and connected with it. In the following stages of the first meiotic prophase, stacks of these cisternae appear closely related to the nucleus and show connections with other cytoplasmic cisternae which are free in the cytoplasm. In the secondary spermatocytes and spermatids, the number of ER cisternae joined to the nucleus decreases; in contrast, the number of free ER cisternae increases. Another peculiar differentiation of the ER, such as the annulate lamellae (AL), appears in the late stages of the first meiotic prophase in relation with the nuclear envelope. AL are conspicuous in secondary spermatocytes and spermatids. In spermatids, AL appear either joined to the nucleus or free in the cytoplasm, in close proximity to the Golgi complex. Finally, AL and other membranes of the ER are released in the cytoplasmic droplets of the maturing spermatids.

Cell Cycle↗
PubMed1980

Renal function in protein-energy malnutrition.

So far, most studies on renal function in children with advanced protein-energy malnutrition have shown an impairment of glomerular filtration rate and renal plasma flow, as well as diminished ability to excrete an acid load and a concentrated urine. Investigation of these functions in eight marasmic infants and eight children with kwashiorkor once they were free of obvious infections and acute electrolyte disturbances has shown a practically normal renal performance.

Child, Preschool↗
PubMed1979

Ultrastructure of testicular biopsy from an XX male.

Ultrastructural study of testicular biopsy specimens from an XX male showed hyalinized seminiferous tubules and tubules containing only mature Sertoli cells. These cells possessed large lipid inclusions as well as microfilament bundles which were perpendicular to the basement membrane and parallel to one another. The basal lamina was thickened and composed of several parallel layers with myofibroblast layers between them. The interstitium showed nodular to diffuse Leydig cell hyperplasia. Four types of Leydig cells were found: 1) normal Leydig cells with crystals of Reinke; 2) cells with abundant microcrystalline inclusions as well as microfilaments and concentric cisternae of smooth endoplasmic reticulum; 3) vacuolated cells containing numerous large lipid droplets; 4) immature Leydig cells. The different ultrastructural abnormalities found in the Sertoli and Leydig cells might be considered as the histological expression of a tubular-interstitial dysgenesis which is reflected in the high levels of gonadotropins and low levels of testosterone.

Basement Membrane↗
PubMed1979

Testicular microlithiasis in 2 children with bilateral cryptorchidism.

Testicular microlithiasis, associated with bilateral cryptorchidism, is studied in 2, 6-year-old children. In case 1 autopsy revealed that 60 per cent of the seminiferous tubules contained completely calcified microliths. Similar mineralized concretions also were found in different areas of the cerebrum and cerebellum. In the testicular biopsy obtained from case 2, 30 per cent of the seminiferous tubules contained microliths showing different degrees of calcification. The study of such calcifications supports the hypothesis that the mineralization process occurs according to the following stages: 1) accumulation of cellular debris in the tubular lumen, 2) deposit of concentric rings of glycoprotein material surrounding the central core and 3) calcification of the glycoprotein lamellar material. The presence of similar concretion in the nervous system as well as the lung in other reported cases suggests that microlithiasis could be a systemic disease.

Calculi↗
PubMed1979

Histogenesis of human extraparenchymal Leydig cells.

From 64 consecutive autopsies of patients with neither testicular nor hormonal pathology, 26 showed extraparenchymal Leydig cells, located mainly in the epididymis and in the spermatic cord. The ultrastructural study of these specimens plus those obtained from 2 patients affected with functional testicular tumors leads to the following conclusions: (1) The origin of ectopic Leydig cells is not interstitial Leydig cells having infiltrated the testicular nerves and migrated along them towards ectopic locations. (2) The ectopic Leydig cells are considered to develop from undifferentiated precursor cells, located extraparenchymally, mainly inside and beside the testicular nerves. These precursor cells are similar to those observed in the testicular interstitium and have an ovoid shape and some cytoplasmic projections. The cytoplasm contains vesicles of smooth endoplasmic reticulum, lysosomes, lipid droplets and abundant microfilament bundles. The transformation from these cells into mature Leydig cells implies a progressive differentiation of the cytoplasmic components involved in steroid biosynthesis.

Adolescent↗
PubMed1979

[Ultrastructural aspects of juvenile xanthogranuloma].

An ultrastructural study of a juvenile xanthogranuloma is presented. Foamy histiocytes reveal several vacuoles of irregular profile containing a type of lipid which is not fixed by osmium tetraoxide. There are also myelin figures. Plasmatic membrane shows numerous digit-like foldings related to collagen fibers. Cytoplasm containing few organelles are restricted to a narrow band around the nucleus and delicate trasverse bandings among the vacuoles. Several intranuclear spheroidal corpuscles have been identified in the histiocytes. Genesis of these foamy histiocytes is discussed probably related to a metabolic derangement of an organelle but in no way related to phagocytosis of fragmented polymorphonuclear leukocytes or Lymphocytes.

Arm↗
PubMed1978

Septate junctions between digestive vacuoles in human malacoplakia.

Typical septate junctions between digestive vacuoles in phagocytic cells of human malacoplakia are described in this paper. Evidence for a honeycomb pattern of hexagonal subunits is presented for their cleft material. Junctions were not observed between other organelles or in cells other than phagocytes. It is assumed that the septate junctions described here may reflect a pathological change in the organization of the membrane components of digestive organelles.

Adult↗
PubMed1978

Formaldehyde-induced appearance of septate junctions between digestive vacuoles.

Tissue biopsies from (1) some chronic inflammatory diseases, (2) a necrotic tumoral process, (3) normal human lymphatic ganglia, and (4) two congenital diseases of the adrenal cortex were selected for study. A block from each biopsy was fixed in glutaraldehyde-paraformaldehyde; a second block was fixed in 10% formaldehyde. In all cases septate junctions between digestive vacuoles did occur in phagocytic cells and some adrenal cortex cells fixed in formaldehyde. These junctions were similar to those reported recently for malakoplakia phagocytes. Consistently, they were not found to attach organelles other than lysosomes derivatives. Both phagocytes and adrenal cortex cells in the material fixed in glutaraldehyde-paraformaldehyde did not display adhesive specializations between digestive vacuoles. This suggests that the septate junctions described herein are artifactuous structures induced by formaldehyde. There is, however, a certain degree of specificity of cells having the capability of developing these septate junctions. It is assumed that the coating material of digestive organelles in phogocytes and some other cells would be responsible for both cell specificity and organelle specificity of the formaldehyde-induced septate junctions.

Adrenal Cortex↗
PubMed1978

Adenomatoid tumour of the epididymis: histochemical and ultrastructural study of 2 cases.

Two cases of adenomatoid tumour of the epididymis are described. Both the histochemical and ultrastructural studied support the concept that it is of mesothelial origin. The histochemical study showed the presence of acid mucopolysaccharides in the lumen of the tubular structures. The epithelial cells presented numerous microvilli in the free surface, junction complexes, wide intercellular channels and a well-developed Golgi complex. Abundant bundles of microfilaments and intracellular spaces were observed in the cytoplasm. Lymphocytes and histiocytes were identified both in the tubular lumen and between the epithelial cells. The stroma of the tumour was made up of dense connective tissue with abundant bundles of elastic fibres. The presence of intracytoplasmic spaces in the epithelial cells and elastic fibres in the stroma had not been previously observed in this tumour.

Connective Tissue↗
PubMed1978

[Excretion in basommatophora and stylommatophora pulmonata (author's transl)].

A comparative study on the kidney of Pulmonata living on land (Stylommatophora) and in fresh water (Basommatophora) was made. The sections performed in three different planes allowed us to know the 3-dimensional pattern of its components: renopericardial duct, kidney sac and ureter. Renopericardial duct runs far into the kidney sac. The duct of Basommatophora is longer and bears also longer cilia than that of Stylommatophora. Kidney sac is similar in both groups and is made up of a wall from which a complex lamellar system spreads into the cavity. Lamellae are longer and more numerous at the dorsal wall, being the lumen of the organ eccentric. The cavity is lined by columnar epithelial cells (nefrocytes) with brush border. Characteristic of the nefrocytes is the presence of a large apical vacuole containing an excretion granule. In Lymnaea there are also lamella lined by cubic epithelium without excretion granule. The union between kidney sac and ureter is different from one another in the three species studied. In Lymnaea the kidney sac narrows and forms the ureter; the connexion in Cryptomphalus is achieved through a 200 micrometer window; and in Helicella there is a duct between both parts. The ureter has a columnar epithelium with very deep infoldings of the basal cell membrane, according to its osmotic regulative function. In Stylommatophora there are primary and secondary ureters, while in Basommatophora there is only one type.

Animals↗
PubMed1977

Multi-tailed spermatozoa in a case with asthenospermia and teratospermia.

A case is presented of an infertile male whose spermatozoa showed low mobility, a high percentage of irregular large heads and a variable number of tails (between 0 and 4). In the spermatozoa with several tails each axoneme, surrounded by its own outer fibres and mitochondrial sheath, arose from its own basal plate. Throughout the middle piece of every spermatozoon all the axonemes were arranged in parallel and were enclosed by the same plasma membrane. Usually, at the beginning of the principal piece, the axonemes became separated. At this level each of them constituted a different tail. In most spermatozoa the fine structure of the tail or tails was normal. The alterations of the inner structure of the tail or tails was normal. The alterations of the inner structure of the flagellum observed in some spermatozoa (enlargement of the fibrous sheath, duplication of the outer fibres and of some peripheral doublets) were independent of the number of tails present. In some cases, an intracytoplasmic coiling of the tail or tails could be observed.

Adult↗
PubMed1977

Congenital testicular lymphangiectasis.

Testicular lymphangiectasis are described for the first time in a patient with bilateral inguinal cryptorchidism. A great number of irregular lymphatic channels was observed within the parenchyma and the tunica vasculosa in both testes. Large and numerous anastomosis between the lymphatic vessels of these two areas could also be seen. The MTD and the TFI of the left testis were normal. Both parameters were very low in the right testis. The association of this fact with the greater development of the lymphatic vessels in this testis strongly supports the idea that testicular lymphangiectasis interfere mechanically with the testis tubular development.

Biopsy↗
PubMed1977

Variable patterns of actin filaments in mammalian skeletal muscle.

The ultrastructural organization of myofilaments in skeletal muscle was studied in four mammalian species (mouse, rat, hamster, goat). In all these species, myofibrils showing irregularly distributed arrays of a variable number of actin filaments (from 6 to 11) were observed. The proportion of such myofibrils and the predominant patterns of actin filaments varied from one species to another. These results are in agreement with those previously reported for human skeletal muscle.

Actins↗
PubMed1977

Irregular patterns of actin and myosin filaments in human skeletal muscle cells.

The ultrastructural study of cross sections of normal skeletal muscle cells showed the existence of irregular patterns of actin filaments in connection with the hexagonal pattern of the myosin filaments. The actin filaments surrounding each myosin filament vary in number from 6 to 11. The most frequent relationship is 9 to 1, followed by 10 to 1 and 8 to 1. The hexagonal pattern of actin filaments was observed only in the 6 to 1 arrays; as the actin filaments increase in number, they tend to form different polygons or circles around the myosin filaments. All described patterns may occur in each sarcomere. The actin to myosin filament ratio varies from 3 to 4 within each individual myofibril. The described variability of the actin filaments arrays leads to several difficulties in an explanation of the mechanism of muscular contraction.

Actins↗
PubMed1977

Bicarbonate stimulation of mitochondrial ATPase. Effect of physical training.

Bicarbonate stimulation of hepatic mitochondrial ATPase activity decreased in rats subjected to intense physical training and reached minimum values at the end of the third week. The stimulatory effect of bicarbonate on mitochondrial heart ATPase remained unaffected under equal conditions. ATPase stimulation by dinitrophenol and sensitivity to oligomycin, both in mitochondria from rat liver or heart, were not affected by physical training. Results suggest that stimulation by dinitrophenol and bicarbonate might be due to effects on separate sites of the enzyme.

Adenosine Triphosphatases↗