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Biomedical subjects

B F Trump

Publications and source records attributed to B F Trump.

At least 271 records · Page 15Linked to original sources
PubMed1978

Explant culture of human colon.

Human colonic epithelium has been cultured as explants in a chemically defined medium for periods of 1 to 20 days. The viability of the explants was shown by the preservation of the ultrastructural features of the colonic epithelial cells and by active incorporation of radioactive precursors into cellular DNA and protein. A progressive decrease in the number of goblet cells, decrease in the depth of the crypts, and a change from a columnar to a cuboidal epithelium were observed. After 20 days in culture the colonic mucosa consisted of a single layer of cuboidal epithelial cells and a few glands. The ability to maintain colonic mucosa in culture was subject to both intra- and interindividual variation. Cultured human colonic mucosa also activated a chemical procarcinogen, benzo[a]pyrene, into metabolites which bound to cellular DNA. A 100-fold interindividual variation in this binding was observed.

Benzopyrenes↗
PubMed1978

Explant culture of human peripheral lung. I. Metabolism of benzo[alpha]pyrene.

Human lung explants have been maintained in vitro for a period of 25 days. Autoradiographic studies indicated that the broncholar epithelial cells, type 2 alveolar epithelial cells, and stromal fibroblasts incorporated 3H-thymidine during the culture. After 7 to 10 days, type 2 cells were the predominant alveolar epithelial cell type. Lamellar inclusion bodies were released from the type 2 cells and accumulated in the alveolar spaces. The metabolism of benzo[alpha]pyrene (BP) in human lung explants cultured for up to 7 days was investigated. Human lung explants had measurable aryl hydrocarbon hydroxylase activity and could metabolize BP into forms that were bound to cellular DNA and protein. Peripheral lung had significantly lower aryl hydrocarbon hydroxylase activity than cultured bronchus but both tissues had similar binding levels of BP to DNA. Radioautographic studies indicated that all cell types in the peripheral lung can metabolize BP. The major ethylacetate extractable metabolites of BP formed by peripheral lung were tetrols and trans-7,8-diol. The primary water-soluble metabolite released with arylsulfatase and beta-glucuronidase was 3-hydroxybenzo[alpha]pyrene.

Aryl Hydrocarbon Hydroxylases↗
PubMed1978

Long-term organ culture of human uterine endocervix.

Explants of human endocervix have been maintained in organ culture for 24 weeks. The epithelium was viable for the entire duration of culture, as demonstrated by ultrastructural morphology and mitotic activity. The epithelium of the explants retained a near normal morphology for 2 to 4 weeks. The only changes observed were decreased mucus secretion in columnar cells, focal epidermoid metaplasia, and an increase in autophagic vacuoles. Subsequently, a slowly progressive transformation of the columnar epithelium into a metaplastic epithelium was observed, with loss of mucus-secreting columnar cells and ciliated cells and the appearance of cuboidal and flattened epidermoid cells, forming often two to three layers. Metaplasia began at the top of the papillae and ridges and extended progressively downwards into the clefts. Nevertheless, in a few areas deep in the clefts, columnar cells retained evidence of mucus secretion during the entire duration of culture. Epidermoid metaplasia appeared to develop in the explants by transformation of columnar mucous cells into cuboidal and flattened cells with epidermoid characteristics. This hypothesis is supported by ultrastructural observations that showed mucus secretion and early keratinization in the metaplastic cells. Mitotic figures were observed with transmission electron microscopy for up to 24 weeks, and all dividing cells contained mucous granules.

Cell Differentiation↗
PubMed1978

Energy dispersive x-ray microanalysis of mitochondrial deposits in sideroblastic anemia.

Energy dispersive x-ray microanalysis was used to analyze mitochondrial and lysosomal iron-containing deposits in sideroblastic anemia. Although it has been previously known that these deposits contain iron by inference from Prussian blue staining, the possible presence of other cations as well as the nature of the anions present has not been identified. The results show that the mitochondrial deposits in erythroid cells have peaks for iron and phosphorus indicating that they do not represent calcifications which commonly occur following injury and that the principal anion may be phosphorus. Studies of hemosiderin and ferritin aggregates in lysosomes of macrophages in the same bone marrow samples again reveal similar peaks for iron and phosphorus. The results also indicate the probable similarity of mitochondrial and macrophage deposists although ferritin itself was never identified in the mitochondrial deposits. The results illustrate the potential of this method for diagnostic and investigative pathology.

Aged↗
PubMed1977

Studies on the pathogenesis of ischemic cell injury. XI. P/O ratio and acceptor control.

Acceptor control index, P/O ratio and inner membrane permeability were examined in isolated mitochondria following periods of renal ischemia for 15, 30, 60, 120, and 240 min. It was noted that the P/O ratio remained unchanged until 1-2 h after the onset of ischemia. A similar change was noted in the contraction rate of isolated ischemic mitochondria after swelling in KCl and addition of ATP+Mg2+. Both changes are probably indications of a basic membrane alteration which correlates with the occurrence of irreversibility of cell injury. In contrast, the swelling rate in KCl and the acceptor control index are altered almost simultaneously with the onset of ischemia. Therefore, acceptor control index and the rate of swelling are affected prior to the point of irreversible cell injury. They are not, therefore, good as indicators of irreversible changes in the inner membrane of mitochondria leading to the "point-of-no-return."

Animals↗
PubMed1977

Studies on the pathogenesis of ischemic cell injury. VI. Accumulation of calcium by isolated mitochondria of ischemic rat kidney cortex.

Mitochondria isolated from rat kidney subject to in vitro ischemia at various time intervals demonstrated a continuous decline of the ability to accumulate calcium following a high initial stable phase of accumulation of calcium which is dependent both on ATP and respiration. This decline occurs during the reversible phase of cell injury and appears to be a sensitive indicator of membrane changes in a binding and/or transport protein or of other membrane permeability characteristics. The morphology of mitochondrial densities related to calcium accumulation in mitochondria varied. Any form of calcium accumulation, resulted in marked swelling of mitochondria. Control renal mitochondria in sucrose were highly condensed. Partially inhibited calcium accumulation in the presence of phosphate was also associated with numerous small spheric or punctate deposits in close relationship to the inner membrane. Uninhibited calcium accumulation resulted in the formation of needle-like structures radiating from such inner membrane associated sites.

Adenosine Triphosphate↗
PubMed1977

Cellular events during partial cerebral ischemia. I. Electron microscopy of feline cerebral cortex after middle-cerebral-artery occlusion.

The feline right cerebral hemisphere was subjected to regional (incomplete) ischemia after clipping the middle cerebral artery for 5, 10, 15, 30 or 60 min, respectively. After each ischemic episode, a 10-min recirculation period was allowed, following which the brain was fixed and processed for electron microscopy. The earliest alterations, detected in the cerebral cortex after 15 min, increased in severity with longer ischemic episodes and were distributed multifocally. There was: (a) marked neuronal mitochondrial matrical swelling and progressive condensation of cytoplasm and nucleoplasm; (b) cytoplasmic swelling of astrocytes with preservation of glial mitochondrial volume; (c) capillaries, oligodendrocytes, myelin sheaths and axis cylinders did not change significantly, even after the longest interval studied: 60 min. This type of tissue reaction appears to be common for those forms of cerebral ischemia, in which circulation is either sustained partially (via collateral arteries) or restored after a period of absolute ischemia. Under these conditions, as yet undefined permeability changes in cell membranes lead to pronounced volumetric alterations of cellular compartments. Although no softening is detectable by digital examination, we suggest that such a set of structural abnormalities constitutes encephalomalacia, or the earliest stage of a lesion which is designated infarction, once it reaches irreversibility.

Animals↗
PubMed1977

The ultrastructure of "brain death". II. Electron microscopy of feline cortex after complete ischemia.

Permanent, complete global cerebral ischemia was induced in cats by filling the cardiovascular system with a plasma substitute (37 degrees C). At variable intervals and up to 120 min thereafter, these feline brains were perfused with aldehydes and processed for electron microscopy. The resulting cellular alterations were homogeneous and uniform throughout the entire brain; they included early chromatin clumping, gradually increasing electron lucency of the cell sap, distention of endoplasmic reticulum and Golgi cisternae, transient mitochondrial condensation followed by swelling and appearance of flocculent densities, and dispersion of ribosomal rosettes. The marked contrast between the structural alterations in permanent, complete ischemia and incomplete cerebral ischemia, suggest differences in their pathogenesis. A basic determinant factor of the structural changes appears to be the volume of flow (serum, plasma, other) which is available at the time of the injury. This analysis of global cerebral ischemia provides some insight on the nature of cellular changes occurring shortly after somatic death.

Animals↗
PubMed1977

Studies on cellular recovery from injury. II. Ultrastructural studies on the recovery of the pars convoluta of the proximal tubule of the rate kidney from temporary ischemia.

The pars convoluta of the proximal tubule of the rat kidney was studied by light and electron microscopy during the recovery phase from transient ischemia. The left kidney was made ischemic by clamping the aorta just above the left renal artery leaving the blood supply to the right kidney and the intestine intact. The pars convoluta (P1 and P2 segments) of the proximal tubule was examined both immediately after various periods of ischemia (15, 30, 60 and 120 min) and after the same ischemic periods followed by 3, 6, 12 and 24 h of blood reflow (= recovery phase). It was found that ischemia for periods up to 60 min were compatible with cell survival whereas 120 min of ischemia gave rise to irreversible cellular changes. Before regaining a normal conformation during the recovery phase, cells made ischemic for 15 min were characterized by slightly decreased cell height, dispersed nuclear chromatin, mitochondria in orthodox conformation and increased numbers of digestive vacuoles and of lipid droplets (stage A2). Most cells made ischemic for 15 min appeared normal when examined after 24 h of reflow. Cells made ischemic for 30 min were also characterized by stage A2 changes after 3 h of reflow and remained in this stage during all recovery periods studied. Cells made ischemic for 60 min first passed into a stage designated A1 and then later during the recovery phase into stage A2. Stage A1 cells were characterized by decreased height, condensed mitochondria, apparently increased numbers and sizes of secondary lysosomes and slightly dilated rough surfaced endoplasmic reticulum; 120 min of ischemia followed by reflow was not compatible with cell survival. Cells made ischemic for 120 min showed the following alterations denoted as stages C and D: shrunken with pyknotic nuclei, swollen mitochondria with large flocculent densities, and filled with different sized vesicles in the apical portion (stage C). Stage D included cells which had undergone necrosis, i.e., phasma membranes and organelles were fragmented and occurred as debris in the tubule lumens.

Animals↗
PubMed1977

Correlation of structure and active transport in the teleost nephron.

In the present study we have extended our investigations concerning the correlation between ultrastructure and active transport in the isolated flounder nephron. The composition of the fish nephron is defined in ultrastructural terms and its behavior when incubated in vitro under short term and long term culture conditions is described. Using the in vitro system originally described by Forster, a variety of inhibitors and conditions which modify cell structure and function were tested. Ultrastructure was correlated with chlorphenol red dye transport. In general, conditions altering active transport also markedly altered cellular ultrastructure. The principal alterations consisted of membrane changes involving various organelles--most importantly the plasma membrane and the mitochondria. Conditions associated with irreversible cell injury could be rapidly produced by interference either with mitochondrial ATP synthesis or with the integrity of the plasma membrane. Both of these rapidly lead to irreversible events which are preceded by reversible structural changes. Organelle changes progress in a rather well-defined sequence of reversible and irreversible stages which are defined. One difference between the two types of interactions is the presence of intramitochondrial calcification which does not occur with direct modification of the mitochondrial electron transport system. The concept of utilizing long term explant organ cultures of fish nephrons for environmental studies is introduced.

4-Chloromercuribenzenesulfonate↗
PubMed1977

Studies on the pathogenesis of ischemic cell injury. VII. Proton gradient and respiration of renal tissue cubes, renal mitochondrial and submitochondrial particles following ischemic cell injury.

Electron transport in tissue cubes, isolated mitochondria and submitochondria particles were examined as a function of ischemic time. It was found that electron transport remains active in all systems beyond the 2 hour ischemic time interval. The NADH stimulated respiration, however, declined after 2 hours of ischemia in ASU (Ammonia-Sephadex-Urea) particles followed by respiration with matrix-located dehydrogenases tested by substrates such as glutamate, alpha-ketoglutarate and pyruvate plus malate. Succinate dependent respiration remains active at control levels. In contrast proton gradient reveals changes in two phases: Phase A is characterized by gradually increasing gradient without valinomycin and by a rapidly declining gradient with valinomycin in the medium. Phase B is characterized by a declining proton gradient with or without valinomycin. It is suggested that the alteration of the proton gradient between 1 and 2 hours ischemia is an important factor contributing to irreversible cell injury.

Animals↗
PubMed1977

Studies on the pathogenesis of ischemic cell injury XV. Reversal of ischemic cell injury in hamster trachea and human bronchus by explant culture.

Hamster tracheal epithelium survived 3 hours of total ischemia at 37 degrees C as demonstrated by its ability to be maintained in organ culture for 7 days subsequent to the ischemic episode. Epithelium ischemic for longer periods did not survive in culture. Human bronchial epithelium obtained from surgically resected lungs showed the acute effects of ischemia, i.e., the cells had dilated endoplasmic reticulum and swollen mitochondria. These cellular effects of ischemia were, however, reversed by placing the bronchus in explant culture. Bronchus obtained at autopsy, 2 to 3 hours following death, showed epithelial cells suffering severe ischemic cell injury, most of which did not survive in culture, but in some cases, a few basal cells survived to form a non-keratinizing squamous epithelium.

Animals↗
PubMed1977

Carcinogenesis in the pancreas. I. Long-term explant culture of human and bovine pancreatic ducts.

Bovine and human pancreatic ductal explants were maintained in long-term culture. Bovine ducts were cultured for 85 days, whereas human ducts have been cultured for up to 60 days. The explants all maintained good ultrastructural preservation for these periods and also incorporated radioactive precursors into protein, RNA, and DNA. Uncultured ducts, which were fixed for electron micrsoscopic study, demonstrated classical signs of reversible cell injury (dilated endoplasmic reticulum and swollen mitochondria), and cultured explants did not. However, the cultured tissues did show sublethal alterations such as the formation of numerous autophagic vacuoles and residual bodies and the accumulation of large lipid droplets. This study demonstrated the feasibility of maintaining pancreatic ducts in long-term explant culture, which enables them to be used in experimental studies involving chemical carcinogens and in structural and functional studies.

Animals↗