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Biomedical subjects

E H Bloch

Publications and source records attributed to E H Bloch.

15 recordsLinked to original sources
PubMed1984

In vivo microscopy of schistosomiasis. IV. The dynamics of the host-parasite responses to Schistosoma mansoni in the hypodermal tissues as observed in transparent chambers in two susceptible hosts during primary and challenge infections.

The migration of Schistosoma mansoni cercariae and schistosomules, and the cellular responses of the hosts to these parasites, in primary and challenge infections, were examined and cine-recorded in vivo in the hypodermal tissues in Algire chambers which had been inserted in dorsal skins of C3H/HeJ mice and cheek pouches of Syrian hamsters, and checked in serial sections. In hamsters, many cercariae penetrated blood vessels within minutes after being injected into their chambers, in contrast to mice, in which penetration into vessels was scanty during the first hour. Schistosomule penetration into blood vessels was slow in both species. To ascertain whether or not the cercariae that had rapidly penetrated blood vessels in hamsters were capable of producing the disease, the chambers were removed a few hours after infection had been induced. Eight to 10 weeks later it was found that the parasites had produced the disease, since egg granulomas were found in the liver of hamsters. The cellular reactions of the hosts to the parasites revealed that granulocytes adhered first and most extensively to the tails of cercariae in essentially equal amounts in primary and challenge infections, but the adherence of such cells to the body of cercariae was greater in challenge infections. Nevertheless, an appreciable number of cercariae in both naive and challenge-infected animals were free of granulocytes or had less than five cells adhering to them. Furthermore, granulocyte adherence to cercariae or schistosomules was not necessarily permanent; the latter were usually free of cells a few hours after infection had been induced. Another difference between naive and challenge infections was that cercarial motility was more rapidly depressed in the latter infections.

Animals↗
PubMed1982

Opsonic requirements for phagocytosis of Borrelia hermsii by human polymorphonuclear leukocytes.

Opsonic requirements for phagocytosis by human polymorphonuclear leukocytes (PMNLs) of a laboratory strain of Borrelia hermsii were examined. Intracellular localization of spirochetes was confirmed by electron microscopy and cinephotomicroscopy. Phagocytosis of 3H-labeled spirochetes was increased with higher concentrations of pooled human serum or greater ratios of spirochetes to PMNLs and was unaffected by diminished classical complement pathway activity. Immune rabbit serum markedly increased phagocytosis of spirochetes beyond levels observed with preimmune rabbit serum. Immune rabbit serum also demonstrated direct activity against B. hermsii, which decreased the motility and viability and increased agglutination of the spirochetes independently of complement. Both the direct activity against B. hermsii and the opsonic activity of immune rabbit serum were eliminated by immunoabsorption of immunoglobulins. These observations suggest a role for the alternative complement pathway and for immunoglobulins in the opsonization of spirochetes for phagocytosis by PMNLs. Immunoglobulins may also play a role in the direct clearance of spirochetes.

Animals↗
PubMed1982

Toward a concept of the functional unit of mammalian skeletal muscle.

The current concepts for the functional unit of mammalian skeletal muscle are reviewed and shown to lack components that are required for determining the unit. To secure a definition for the functional unit, requisite criteria were selected, and the manner by which these criteria were used to define the functional unit are discussed. For deriving a definition of the unit the following values were obtained: the unit is associated with the total length of the muscle fiber, which may achieve a maximum length of 60 cm; it exhibits an average diameter of 40 micrometers/fiber; it is associated with a capillary net whose length (arteriole to venule) is about 750-1,000 micrometers max; the net exhibits a capillary-to-fiber ratio for long capillaries of approximately 1-1.5:1, with a transverse capillaries occurring approximately every 150 micrometers; and it has a fiber-to-motor end plate ratio of 1:1. The correlation between anatomic data and functional data indicate that a functional unit of muscle is delimited by about 1 mm2 of the cross-sectional area of a muscle bundle, since this is the maximum area under autonomic control of its particular arteriolar blood supply, the metabolic throttle that determines the power being expended by the muscle bundle.

Animals↗
PubMed1979

Inflammation in schistosomiasis.

The inflammatory reactions that occur in schistosomiasis are reviewed. The inlammation is due to the migration of worms and eggs through the host's tissues via the vascular system. The greatest damage to the host is produced by the eggs which induce an extensive granulomatous inflammation in the intestine and liver. While the host modulates the course of the disease by developing a cell mediated immunity, ultimately the inflammation in the liver interferes with portal blood flow that may lead to portal hypertension, portal-systemic shunts and fatal hematemesis.

Animals↗
PubMed1975

In vivo microscopic observations of the pathogenesis of acute mouse viral hepatitis.

In vivo microscopy of the liver was undertaken to determine the extent of involvement of the hepatic microvascular system in mice infected with viral hepatitis (MHV-3). It was found that the major effects of the disease were produced in localized areas where parenchyma, sinusoids and blood were obliterated. However, immediately peripheral to these lesions blood flow and vessels were unaffected other than by localized hypertrophy of Küpffer cells. While each lesion produced a sinusoidal block to blood flow, portal hypertension did not occur even in the presence of extensive focal and confluent necrosis.

Animals↗