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Biomedical subjects

A Sesso

Publications and source records attributed to A Sesso.

At least 55 records · Page 3Linked to original sources
PubMed1988

Morphometric study of normal and adenomatous pituitary somatotrophs in humans.

Somatotrophs from ten pituitary adenomas were evaluated morphometrically by light and electron microscopy using the following parameters: a) nuclear, cytoplasmic and cell volumes; b) volume density, total volume, surface density, total surface and surface/volume ratio of secretory granules, mitochondria, rough endoplasmic reticulum and Golgi apparatus, and c) the number of secretory granules and mitochondria per micron3 of cytoplasm and per cell. The results were compared (p less than 0.05 and p less than 0.10) with those obtained from somatotrophs identified in five normal pituitaries. The data obtained indicate that: a) in the adenomas, the number of secretory granules per cell cannot be accurately evaluated from their apparent number in sectioned cell profiles; b) there are two basic sub-types of adenomatous somatotrophs defined according to the mean secretory granule diameter; cells in which granule diameter is inferior to 180 nm exhibit distinct morphological features such as nuclear pleomorphism, the presence of gross bundles of intermediate sized filaments or fibrous bodies in the cytoplasm and a variable number of secretory granules. Adenomas constituted mainly by these cells were found in younger patients, suggesting the more aggressive nature of these tumours, thus warranting close clinical follow-up of such patients; and c) in both types of adenomatous cells, the organelles directly involved in the secretory process, i.e., the rough endoplasmic reticulum and Golgi apparatus, are larger than in the control cells; however, the ratio between the surfaces of these two compartments does not differ among the three groups studied.

Acromegaly↗
PubMed1988

Annulate lamellae as a precursor or a product of paired cisternae in human adenomatous parathyroid cells.

Clusters of chief cells from a fragment of human parathyroid adenoma possess relatively few rough endoplasmic reticulum (RER) cisternae with scattered annulate lamella (AL) pores in cytoplasmic sectors close to the nucleus. Some of these cisternae exhibit winding profiles with smooth segments lying very close to the outer nuclear membrane. Other groups of cells exhibit well-developed stacks of RER either in continuity with or separated from AL. Two other tumor fragments show chief cells with few RER cisternae scattered in the cytoplasm and possess stacks with various amounts of AL and/or paired cisternae (PC), occasionally at perinuclear sites. Compartmental continuity between AL and PC is a frequent finding. Pore density in AL varies considerably between the stacks from different cells.

Adenoma↗
PubMed1988

Interaction between macrophage and parasite cells in lobomycosis. The thickened cell wall of Paracoccidioides loboi exhibits apertures to the extracellular milieu.

Lesioned, cutaneous, tissue fragments from five indians of the Caiabi tribe with lobomycosis, living in the Xingu National Park (Central Brazil), are analyzed by light and electron microscopy. Clusters of macrophages filled with parasite and/or cell wall debris, separated by collagen fiber bundles, characterize the morphological pattern seen in thick and thin sections. Paracoccidioides loboi within the phagocytic cells are multinucleate organisms whose cytoplasm contains mitochondria with few cristae, ribosomes and vacuoles; a large, dense, globular body and peculiarly curved mitochondrial profiles are described. From the outer portion of the double layered parasite cell wall, radial projections commonly emerge, rendering the structure conspicuously thicker and more irregularly surfaced than that seen in many other phagocytized yeast cell species. The cell wall layers from fungi possessing distinct subcellular organization show a weak or no reaction for acid phosphatase. Most of the foamy cells commonly seen by light microscopy are macrophages filled with fungal cell wall remnants which exhibit marked acid phosphatase activity. Occasionally, microchannels extending from the outer layer of the parasite cell wall to the macrophage surface and exocytic-like openings, possibly derived from the fusion of the macrophage membrane covering the parasite cell wall and the macrophage plasmalemma can be seen. Through such routes, material of texture and density similar to that of the outermost cell wall layer appears to be deposited extracellularly.

Adult↗
PubMed1988

Lanthanum nitrate labelling of the outer cell wall surface of phagocytized Paracoccidioides loboi in human lobomycosis.

Lesioned skin tissues from a female Caiabi indian with lobomycosis were processed for routine electron microscopy using, in the initial steps, solutions containing 2% lanthanum nitrate. The pattern of tracer distribution suggests that the tracer penetrates into the cavity containing the parasite through exocytotic-like apertures situated at the cell wall outer region. The tracer also infiltrates the virtual space between the cell wall and its recovering membrane, spreading over varying areas of the outer surface of the cell wall. The contrast imparted to the pericellular macrophage space by the lanthanum nitrate enabled easy localization of fibrillar, cell wall derived material which reaches the adjacent extracellular milieu.

Adult↗
PubMed1987

Structural and functional response of the isolated toad skin to mucosal lithium.

Structural and functional changes induced by long-term Li-exposure of the outer surface of toad skin was studied. Electron microscopy revealed that total Na by Li replacement in the outer compartment of short-circuited toad skin promotes a conspicuous cellular damage expressed as focal swollen cells with altered intercellular spaces and nuclear morphology. Short-circuit current (SCC) decreases by about 70% over the first 60 min after 115 mmol/l Li-exposure. An amiloride sensitive transepithelial Li transport remains intact over a further 150 min despite the epithelial damage, indicating that the pathways across the apical barrier are functioning. Increase of the paracellular permeability is detected by elevation of Na-efflux. Partial 50% or 10% Na by Li replacements induce minor structural alterations and are not sufficient to trigger appreciable Na-efflux and SCC alterations. Therefore, low Li concentrations are less effective than 115 mmol/l in promoting morphofunctional responses. Although ouabain and Li reduce the SCC, ouabain does not promote structural lesions, showing that Li-inhibition of Na transport by itself is not responsible for the observed morphological alterations. In the light of this study, Li utilization as a tool to investigate transepithelial Na transport requires careful judgement.

Animals↗
PubMed1987

Salivary duct carcinoma: ultrastructural and histogenetic considerations.

Two cases of salivary duct carcinoma were examined by light and electron microscopy. Histologically, the tumor presented cribriform and papillary patterns together with comedonecrosis. Electron microscopy revealed duct cells with microvilli, interdigitations, and apical vesicles. No myoepithelial cells were observed. These findings suggest a ductal origin other than from the intercalated duct or its precursor element. The importance of separating the salivary gland adenocarcinomas is discussed.

Adenocarcinoma↗
PubMed1987

Epithelioid hemangioendothelioma of the gingiva: case report and ultrastructural study.

A case of epithelioid hemangioendothelioma that occurred in the mandible of a 4-year-old boy is reported, and the tumor's ultrastructural features are examined. The presence of small atypical vascular lumina, rounded or fusiform endothelial cells packed with intermediate-sized microfilaments, Weibel-Palade bodies, a small amount of distended rough endoplasmic reticulum, pinocytotic vesicles, and a basal lamina are shown. The remarkable finding of large, apparently "free" spaces within the cells that exhibit vesicle formation and sections of protrusions similar to those found in endothelial cells is discussed.

Child, Preschool↗
PubMed1987

Must fat emulsions and parenteral nutrition solutions be given through separate circuits?

To test the stability of fat emulsions with parenteral nutrition (PN) solutions, 10% soybean fat emulsion (FE) was suspended in PN solutions containing amino acids, electrolytes, vitamins, and different glucose concentrations. Six different mixtures were prepared and analyzed after 15 minutes or 24 hours, under transmission electron microscope: 10% fat emulsion (FE); FE + PN solution with 5% glucose (15 minutes); FE + PN solution with 5% glucose (24 hours); FE + PN with 12.5% glucose (24 hours); FE + PN with 25% glucose (24 hours); and FE + pure glucose 50% (24 hours). The addition of FE to PN solutions containing 5% to 25% glucose did not cause coalescence, aggregation, or confluence of the liposomes or damage to their surface in the first 24 hours after admixture. However, the suspension of fat emulsion in a 50% glucose solution coalesced liposomes and the droplets were nearly all aggregated. We conclude that mixtures of FE with PN solutions with glucose are stable for at least 24 hours and are suitable for clinical use.

Drug Stability↗
PubMed1987

Morphometric evaluation of zymogen granule membrane transfer to Golgi cisternae following exocytosis in pancreatic acinar cells from suckling newborn rats.

Pancreatic acinar cells from unfed, newborn rats and sucking for 4, 8 and 16 h were studied morphometrically in semi- and ultrathin sections. In the cells of the unfed, newborn rats, numerical and volume densities of the zymogen granules (ZG) and volume of the Golgi apparatus are respectively the highest and lowest observed during peri- and postnatal life. Cisternae of the rough endoplasmic reticulum (RER) appear irregularly disposed among the ZG. Once feeding starts, cytoplasmic volume becomes progressively reduced until the 16th hour owing to sustained exocytosis of ZG contents. The decline in numerical density of ZG between 0 and 4 h revealed the minimum number of ZG exocytosed in the first 240 min. The sum of the membrane surfaces measured in the various subcellular compartments [RER, condensing vacuoles (CV), Golgi cisternae (GC), Golgi apparatus-associated microvesicles (GM), 'other structures', apical and basolateral plasmalemmae and mitochondria] did not vary significantly in the various groups of rats. After 4 and 8 h, the net amount of cellular ZG membrane surface internalized represents 10% and 15% respectively of the total measured cell membrane. These quantities are sufficient to account for the expressive increase in membrane surfaces occurring at these times in CV, GC, and GM. The curves showing membrane surface decrease in ZG and increase in the Golgi appear to express a precursor----product relationship. The results of topochemical reactions are consistent with the interpretation that part of the ZG membrane internalized after exocytosis induced by alimentary stimulus is reused to expand and/or form trans (thiamine pyrophosphatase positive) and trans-most (acid phosphatase positive) GC.

Animals↗
PubMed1984

The use of subcutaneously implanted araldite disks for microstructural studies of inflammatory macrophages.

Subcutaneously implanted epoxy resin disks can be used instead of glass coverslips in mice to recruit inflammatory macrophages. Implanted araldite disks exhibited large numbers of macrophages on both surfaces which could be observed conveniently by light and phase contrast microscopy. Most importantly, the disks can be embedded directly in an araldite mixture for the preparation of thin sections for electron microscope examination.

Animals↗
PubMed1984

Quantitative description of a teleost exocrine pancreas. Ultrastructural morphometric study of nonstimulated acinar cells.

The quantitative analysis of exocrine pancreas was fulfilled in teleost fish ( Pimelodus maculatus). The volume fraction occupied by acinar cells, blood vessels and ducts has been assessed by point-counting volumetry in 0.25 micron araldite sections. Measurements of the diameters of the transections of acinar cells nuclei and nucleolus allowed the assessment of the mean nuclear and nucleolar volume according to the method of Bach (1963). With these data, the cytoplasm nuclei and nucleolus volume was calculated in cubic micrometers. Morphometric ultrastructural data was obtained by applying over the electronmicrophotographs (X 21,000) a test system of 84 segments regularly spaced one from another (Weibel 1966). The results obtained was analysed and compared to the mammalian.

Animals↗
PubMed1983

Freeze-fracture characterization of the outermost Golgi cisterna (OGC) in rat pancreatic acinar cells.

The outermost Golgi cisterna (OGC) frequently exhibits 55 nm diameter protuberances in P fracture faces and corresponding depressions, or pits, in E faces. When these protuberances (pits) appear regularly disposed, OGC faces are recognizable at relatively low electron microscopic magnifications. The mean particle width is less in OGC (6.4 nm) than in rough ER (7.9 nm) P faces, while particle number per unit area is respectively 70% and 100% greater in OGC P and E faces than in corresponding ER faces. The rather small OGC P face particles are better resolved at a relatively low shadowing angle. These differences in particle size (for P faces) and density between OGC and rough ER faces are detectable by inspection and may be used in the recognition of OGC faces devoid of protuberances (in P faces) and pits (in E faces). Fusion of presumably rough ER-derived microvesicles form short double-bossed tubular elements which constitute the OGC initial structure. These tubules enlarge by addition of microvesicle membrane and contents forming a characteristic sheet-like bossed structure.

Animals↗
PubMed1983

Volume changes during mitosis in pancreatic acinar cells of the rat.

The volume of interphasic and mitotic pancreatic acinar cells of 20-day-old rats was estimated by analysis of drawings from Araldite-embedded serial thick sections. Assuming the average interphase cell volume to be 100%, the volume of prophase cells was 145%, reaching a volume of 180% during anaphase. Postmitotic acinar cell volume was 74%.

Analysis of Variance↗
PubMed1983

Tubulated bodies in teleost (Pimelodus maculatus) endothelial cells.

In the present report tubulated granules are described for the first time in a freshwater teleost (Pimelodus maculatus) endothelial cells. Some ultrastructural characteristics as well as the localization and distribution suggest that tubulated bodies represent the teleost counterpart of the Weibel-Palade bodies described in other animal classes.

Animals↗
PubMed1982

Pigment biogenesis in freshwater shrimp ventral nerve chord chromatophores.

The possible biogenesis of two pigment granule types present in the monochromatic, brown chromatosomes enveloping the ventral nerve chord of the freshwater palaemonid shrimps Macrobrachium acanthurus, M. heterochirus and M. olfersii is examined by transmission electron microscopy in thin section and freeze fracture replicas. Prominent, membrane limited granules are suggested to have their origin in a complex, juxtanuclear, smooth endoplasmic reticulum labyrinth, continuous with the nuclear envelope. Amembranous, lipocarotenoid granules possibly derive from the external surface of the smooth endoplasmic reticulum. Nuclear envelope and SER membranes contain numerous 11 nm diameter intramembranous particles while pigment granule membranes exhibit fewer particles. A dictyosomal origin for the lipocarotenoid granules is discounted. Granulogenesis is suggested to be a continuous process in crustacean chromatophores.

Animals↗