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Biomedical subjects

J M Rivera-Pomar

Publications and source records attributed to J M Rivera-Pomar.

At least 19 recordsLinked to original sources
PubMed1993

Histochemical and morphometrical ageing changes in human vocal cord muscles.

A histochemical and morphometrical study of thyroarytenoid and posterior cricoarytenoid human muscles was done in 43 human adults (38 males, 5 females) with ages ranging from 46 to 87 years. Vocal cord muscles were taken from laryngectomy specimens with carcinoma (25) and from autopsies (18), excluding those with neuromuscular diseases. In all cases the studied vocal cords were clinically and histologically normal in appearance. Only 2 patients received radiotherapy or chemotherapy. Posterior cricoarytenoid muscle was studied in 6 patients with larynx cancer. Mean diameter of thyroarytenoid muscle type I fibers (n = 128) was 38.46 microns and for type II 39.68 microns; fiber percentage values (n = 127) were 44.16% for type I and 55.84% for type II. Mean diameter (n = 6) of posterior cricoarytenoid muscle type I fibers was 42.69 microns and of type II 46.56 microns; type I fibers percentage was 66.15% and type II 33.85%. Statistical regression analysis revealed a progressive decrease in thickness of the mucosa and lamina propria in the right vocal cord along the ageing process. A low increase of endomysial tissue with a low decrease in perimysium in both vocal cords was noticed. In thyroarytenoid muscle, a low increase in type I fiber percentage and a decrease in type II fiber percentage were found. Posterior cricoarytenoid muscle showed a significant decrease in type I fiber percentage and diameter, corresponding to the same increase in variables of type II fibers.

Adenosine Triphosphatases↗
PubMed1989

Human otoconial crystal growth. An approach from morphological and morphometric data.

The otoconium genesis was evaluated by morphometric procedures using transmission and scanning electron-microscopic techniques for human fetuses of 50, 110, 134, 173, 210, 220 and 232 mm crown-rump length. Different otoconial crystalline habits were found. For the elongated otoconia (hexagonal prism) different parameters were measured: (1) the mean cleavage angle value of the terminal rhombohedron was 102 (SD 0.65), which was independent of the fetal age; (2) large and short axes show a linear growing law in function of the fetal age, and (3) the otoconial volume grows following a quadratic law. A hypothesis about the physicochemical growth conditions is postulated.

Crystallization↗
PubMed1988

Genesis and decay of the foregut: development and repair.

The microscopic anatomy of the oesophago-gastric territory is interpreted as the result of the interaction of three main phenotypes: squamous, oxyntic and intestinal. This synthesis allows the comparison between phenotype development, atrophy and metaplasia. The concomitances in the processes of development and repair lead to the proposal of an intestinalization gradient inherent to the oesophago-gastric field. This hypothesis permits an integration of the epithelial changes associated with gastritis and oesophagitis together with ontogenesis. The global tendencies in epithelial development and repair are discussed; a link between the two appears evident. The shifting potential of the progenitor gland zones in development and repair is in consonance with Wolpert's theory of positional information.

Cell Differentiation↗
PubMed1985

Solitary Langerhans' cell granulomatosis of the stomach associated with gastric carcinoma.

A case of Langerhans' cell granulomatosis associated with gastric adenocarcinoma is reported. A review of the literature demonstrate an association of this entity with Hodgkin or non-Hodgkin lymphomas alone. The discussion is centred on differential diagnosis from the pseudo-sarcoid granulomatous reaction. Further reports may assist in classifying the granulomatous reaction to tumours into two types, epithelioid and Langerhans.

Adenocarcinoma↗
PubMed1985

Non-conventional chondrosarcomas and chondrogenesis.

Pattern formation in chondroid development is compared with growth models exhibited by mesenchymal and myxoid chondrosarcomas. The results reveal strong similarities between mesenchymal chondrosarcoma and normal chondrogenesis. The fine vascularization of the tumor lobules of myxoid chondrosarcoma is discussed in relation to chondroid differentiation. A common histogenetic approach to the interpretation and classification of these neoplasias is proposed.

Animals↗
PubMed1984

Skeletal muscle changes in chronic alcoholic patients. A conventional, histochemical, ultrastructural and morphometric study.

Muscle biopsies of 20 alcoholic patients (15 males and 5 females), most of whom had liver disease and with no clinical or analytical evidence of neuromyopathy, were studied. 10 abstemious patients with no neuromuscular disease were selected as controls. Conventional histology failed to show significant skeletal muscle changes. A characteristic histochemical picture of tubular aggregates was found in one patient. An enlargement of the intermyofibrillar space with increase in glycogen deposition and fat droplets were detected ultrastructurally while 2 of the patients showed tubular aggregates. The mitochondriae of the alcoholic patients had a smaller perimeter and area than those of the control group (P less than 0.004 and P less than 0.008, respectively). These results suggest that the prolonged ingestion of alcohol can cause a mitochondrial alteration only evidenced by morphometry, with poor clinical, biochemical, electrophysiological and histological expression of myopathy. These findings can represent an early stage of alcoholic skeletal muscle injury.

Adenosine Triphosphatases↗
PubMed1983

Structure of the non-lymphoid cells during the postnatal development of the rat lymph nodes. Fibroblastic reticulum cells and interdigitating cells.

This study describes the postnatal development of the nonlymphoid cells with special reference to the fibroblastic reticulum cells (FRCs) and interdigitating cells (IDCs). The first lymphocytes of the neonatal lymph nodes are located in the developing deep cortex units (DCUs) identified by the Gomori's technique for reticulin fibres. Ultrastructural studies demonstrate that FRCs form the stroma of the DCUs. By light and electron microscopy, it is demonstrated that FRCs occupy the outer cortex in the following stages of development of the lymph nodes. Thus, FRCs form the stroma of the primary follicles and, later, are transformed in follicular dendritic cells (FDCs) of the germinal centres. Immature or pro-IDCs appear as migrating elements in the deep cortex of lymph nodes of the neonatal rats. The ultrastructure of the pro-IDCs resembles that of the mature IDCs but not that of the phagocytic cells. Pro-IDCs are transformed into mature IDCs whose cytoplasmic expansions contact lymphocytes via tight junctions. Some of these lymphocytes are likely apposed to FRCs of the DCUs. No cells containing Birbeck granules were found in the parenchyma of the lymph nodes during the postnatal development. The role of these nonlymphoid cells is discussed with respect to the immunologic function of mammalian lymph nodes.

Animals↗
PubMed1983

Rhabdomyomatous dysplasia of lung and congenital diaphragmatic hernia.

A previously unrecognized association of pulmonary rhabdomyomatous dysplasia and congenital posterolateral diaphragmatic hernia is reported. The authors subscribe to the concept of ectopia and postulate an anomalous migration of cervical "diaphragmatic" rhabdomyoblasts as the most probable origin of the pulmonary muscle fibers.

Female↗
PubMed1983

Early apocrine change in hyperplastic cystic disease.

Biopsy material from 42 cases of florid hyperplastic cystic disease of the breast were reviewed and were found to have foci of apocrine metaplasia. This appearance was limited to the ductular epithelium of hyperplastic lobules. It is believed that this scattered change is an initial feature in relation to the genesis of apocrine-lined and fully developed cysts.

Breast↗
PubMed1983

A study of the development of utricular and saccular maculae in man and in rat.

The ultrastructural development of utricular and saccular maculae in man and rat is described. In the human fetus with a crown-rump length (CRL) of 50 mm, the utricular and saccular epithelia consist of a pseudostratified layer of dark and light cells without nerve endings. In human fetuses of 110 and 220 mm CRL, as well as in 17- and 18-day-old rat embryos, it is already possible to identify sensory and supporting cells in various stages of differentiation. Nerve endings can also be found. Ciliogenesis is present in both sensory and supporting cells of the 17- and 18-day-old rat embryos. During epithelial differentiation a heavy calcium deposition occurs on vestibular cells of both man and rat. Otoconial mineralization increases gradually as epithelial maturation advances. Phagocytosis of otoconia by free macrophages occurs in 50-mm CRL human fetuses. Vestibular nerve myelination is asynchronous and is present in 110-mm CRL human fetuses and in 30-minute postpartum rats.

Acoustic Maculae↗
PubMed1982

Benign schwannomas: a histopathological and morphometric study.

A conventional histopathological and quantitative morphometric study of 28 capsulated peripheral and spinal nerve benign schwannomas demonstrated linear and parabolic correlation between Antoni B tissue, vascularity and tumour size. The results support the endoneural connective tissue origin of Antoni B, and suggest a model of tumor growth that is partially limited by the growth potential of the Antoni B and/or the vascular component.

Humans↗
PubMed1980

Leukaemoid reaction and eosinophilia in "inflammatory fibrous histiocytoma".

A case of retroperitoneal inflammatory fibrous histiocytoma associated to a marked granulocytic blood reaction and high eosinophilic count is reported. The paraneoplastic nature of the haematological findings and their probable prognostic role are discussed. Ultrastructurally the tumor does not differ significantly from "non inflammatory" fibroxanthosarcomas.

Aged↗
PubMed1980

Focal fibrous disease of breast. A common entity in young women.

The study concerns a problem of practical importance in the daily routine work. 218 cases of focal fibrous disease of the breast were classified into three types with conventional methods of pathohistology and statistics. The peak incidence between 20 and 25 years is considerably lower than the incidence figures reported by other authors. The authors postulate the progressive evolutive nature of the lesion.

Adolescent↗