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Biomedical subjects

E Schmid

Publications and source records attributed to E Schmid.

At least 19 recordsLinked to original sources
PubMed1979

The effect of dopamine on hepatic-splanchnic blood flow after open heart surgery.

Dopamine (3,4 dihydroxyphenylethylamine) increases cardiac output and in particular the renal blood flow at the expense of other regional vascular beds not yet defined. Since the results of dopamine-induced changes in splanchnic perfusion are inconsistent, the effect of 6 mcg/kg/min dopamine was studied in 9 patients early after open heart surgery. Estimated hepatic blood flow (EHBF) was calculated from the concentration-time slopes of Indocyanine Green (ICG, Cardiogreen) in arterial and hepatic venous blood following single intravenous injection. Blood volume was measured using 51Cr tagged red cells. Cardiac output was determined according to the Fick method. 6 mcg/kg/min dopamine caused a mean EHBF-increase of 82%, from 492 +/- 64 to 824 +/- 80 ml/min/m2 (P less than 0.001). Related to the corresponding increase in cardiac index (CI) from 2.6 +/- 0.2 to 3.8 +/- 0.3 1/min/m2 (P less than 0.001), the EHBF/CI-ratio changed from 18.5 to 21.7% (P less than 0.025). The arterial-hepatic venous oxygen difference was reduced from 7.40 +/- 0.53 to 4.91 +/- 0.60 Vol% (P less than 0.001). It was concluded that splanchnic perfusion does not contribute to the preferential increase of renal blood flow under dopamine under the above mentioned conditions. Dopamine had the most beneficial effect on EHBF in two cases where the latter was severely reduced.

Adult↗
PubMed1979

Formation and involution of Mallory bodies ("alcoholic hyalin") in murine and human liver revealed by immunofluorescence microscopy with antibodies to prekeratin.

Antibodies raised against prekeratin intensely and specifically stain, in immunofluorescence microscopy, Mallory bodies ("alcoholic hyalin") present in livers of human alcoholics and griseofulyin-treated mice. The high sensitivity of this method allows the identification of small distinct cytoplasmic structures that are observed during early stages of Mallory body formation, especially frequent in the perinuclear cytoplasm, as well as during stages of Mallory body disintegration and disappearance, such as after withdrawal of the drug. In the latter situation, the prekeratin-containing small particles exhibit a characteristic pattern of arrangement in the hepatocyte periphery. Electron microscopy illustrates that such small bodies are heap-like aggregates of typical Mallory body filaments. Immunofluorescence studies with antibodies to isolated prekeratin polypeptides from bovine hoof or muzzle epidermis show that Mallory body filaments, in particular those in human liver, are immunologically more closely related to prekeratin of tonofilaments from living epidermal cells (stratum spinosum). The data indicate that Mallory bodies contain a pathologic form of prekeratin-like material. They also suggest that disorders of cytoskeletal structures of the intermediate-sized filament class are associated with specific diseases and can be visualized and characterized by immunofluorescence microscopy by using antibodies to constitutive proteins of such filaments.

Animals↗
PubMed1979

Calculation of the dose-rate dependence of the decentric yield after Co gamma-irradiation of human lymphocytes.

The dose relation for dicentrics after in vitro Co gamma-irradiation of human lymphocytes with dose rates of 50 and 1.7 rad/min fit the linear-quadratic function y=alpha D + beta D2. Compared with 50 rad/min, after 1.7 rad/min alpha D was unchanged, whereas beta D2 was decreased by 36 percent. By applying the mean interaction time t approximate to 110 min for primary breaks, determined in an earlier experiment, and Lea's G-function, a theoretical dose relation for 1.7 rad/min can be calculated from the corresponding experimental curve. Thus, from calibration curves with conventional dose rates dose-effect curves for low dose rates can be derived without the need for time-consuming chromosome analyses.

Cells, Cultured↗
PubMed1979

Intermediate-sized filaments of human endothelial cells.

Human endothelial cells prepared from unbilical cords are characterized in parallel by electron microscopy and indirect immunofluorescence microscopy using specific antibodies against different classes of intermediate-sized filaments. The strongly developed, loose bundles of intermediate-sized filaments typically found in these cells are not decorated by antibodies against prekeratin or antibodies against smooth muscle desmin. They are, however, strongly decorated by antibodies directed against murine "vimentin," i.e., the 57,000 mol wt polypeptide which is the major protein of the intermediate-sized filaments predominant in various cells of mesenchymal origin. Cytoskeletal preparations greatly enriched in intermediate-sized filaments show the enrichment of a polypeptide band comigrating with murine vimentin. This shows that the intermediate-sized filaments that are abundant in human endothelial cells are predominantly of the vimentin type and can be demonstrated by their cross-reaction with the vimentin of rodents. These data also strengthen the evidence for several subclasses of intermediate-sized filaments, which can be distinguished by immunological procedures.

Animals↗
PubMed1979

Simultaneous expression of two different types of intermediate sized filaments in mouse keratinocytes proliferating in vitro.

The intermediate-sized filaments present in epidermal keratinocytes derived from mouse skin and in an established cell line (HEL) derived from spontaneous transformation of murine keratinocytes grown in vitro, have been examined by immunofluorescence microscopy, using antibodies directed against subunit proteins of different classes of intermediate-sized filaments, as well as by electron microscopy and gel electrophoresis of cytoskeletal preparations highly enriched in intermediate-sized filaments. The keratinocytes derived from neonatal skin, which are capable of only limited replication in vitro, show only a single type of intermediate-sized filaments, i.e., the tonofibril-like arrays of filaments containing prekeratin. HEL cells, which proliferate indefinitely in vitro, retain the tonofilament-like structures typical of differentiated epidermal cells but in addition display intermediate-sized filaments of the vimentin type, i.e., the filament system typically found in mesenchymal and mesenchyme-derived cells. We discuss the possibility that (i) the advent of vimentin-type filaments in epidermal cells in culture is related either to the transformed state or the in vitro growth conditions as such and (ii) other differentiated epithelial cells proliferating in vitro may have more than one system of intermediate-sized filaments.

Animals↗
PubMed1979

Identification and characterization of epithelial cells in mammalian tissues by immunofluorescence microscopy using antibodies to prekeratin.

The occurrence of intermediate-sized filaments containing prekeratin-like proteins ('cytokeratins') has been examined in various organs of rat and cow by electron microscopy and by immunofluorescence microscopy on frozen sections using antibodies to defined constitutive proteins of various types of intermediate-sized filaments (prekeratin, vimentin, desmin). Positive cytokeratin reaction and tonofilament-like structures have been observed in the following epithelia: epidermis; ductal, secretory, and myoepithelial cells of sweat glands; mammary gland duct; myoepithelial cells of lactating mammary gland; milk secreting cells of cow; ductal, secretory, and myoepithelial cells of various salivary glands; tongue mucosa; bile duct; excretory duct of pancreas; intestinal mucosa; urothelium; trachea; bronchi; thymus reticulum, including Hassall corpuscles; mesothelium; uterus; and ciliated cells of oviduct. None of the epithelial cells mentioned has shown significant reaction with antibodies to vimentin, the major component of the type of intermediate-sized filaments predominant in mesenchymal cells. The widespread, if not general occurrence of cytokeratin filaments in epithelial cells is emphasized, and it is proposed to use this specific structure as a criterion for true epithelial character or origin.

Animals↗
PubMed1979

Differential location of different types of intermediate-sized filaments in various tissues of the chicken embryo.

The location of constitutive proteins of different types of intermediate-sized (about 10 mm) filaments (cytokeratin, vimentin, desmin, brain filament protein) was examined in various tissues of 11--20 day chick embryos, using specific antibodies against the isolated proteins and immunofluorescence microscopy on frozen sections and on isolated serous membrane. The tissues studied which contained epithelia were small intestine, gizzard, esophagus, crop, liver, kidney, thymus, mesenteries, and epidermis. The results show that the different intermediate filament proteins, as seen in the same organ, are characteristic of specific lines of differentiation: Cytokeratin filaments are restricted to--and specific for--epithelial cells; vimentin filaments are seen--at this stage of embryogenesis--only in mesenchymal cells, including connective tissue, endothelial and blood cells, and chondrocytes; filaments containing protein(s) related to the subunit protein prepared from gizzard 10 nm filaments (i.e., desmin) are significant only in muscle cells; and intermediate filament protein of brain, most probably neurofilament protein, is present only in nerve cells. We conclude that for most tissues the expression of filaments of cytokeratin, vimentin, desmin, and neurofilament protein is mutually exclusive, and that these protein structurees provide useful markers for histochemical and cytochemical differentiation of cells of epithelial, mesenchymal, myogenic, and neurogenic differentiation.

Animals↗
PubMed1979

Ultrastructural, biochemical, and immunologic characterization of Mallory bodies in livers of griseofulvin-treated mice. Fimbriated rods of filaments containing prekeratin-like polypeptides.

Mallory bodies (MBs) induced in hepatocytes by long term feeding of mice with griseofulvin were isolated, purified, and examined by electron microscopy in ultrathin sections and negatively stained preparations. The major structural component of the MBs was randomly oriented, unbranched rods of filaments; these were usually 175 to 250 nm. long and 14 to 20 nm. thick and covered by a dense fimbriate coat of laterally projecting 1.5- to 3-nm. thick threads. Such lateral threads could extend for more than 20 nm. and seemed to be involved in the interconnection of adjacent filaments and their association and aggregation into MBs. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the purified filament material showed six major polypeptide bands with apparent molecular weights ranging from 48,000 to 66,000. When the portion of the MB filament material that was soluble in solutions containing 8 M urea was allowed to reaggregate upon removal of the urea, an enrichment of one of the polypeptide components (approximate molecular weight, 64,000) was observed. When frozen sections of liver tissue MBs were subjected to indirect immunofluorescence microscopy, they were specifically revealed by guinea pig antibodies directed against purified bovine prekeratin. No significant accumulation of MBs was observed with a series of other antisera, including those containing antibodies against tubulin, actin, and vimentin, the major protein of the intermediate sized filaments predominant in mesenchymal cells. The observations suggest that MBs in livers of griseofulvin-treated mice, and probably also of human alcoholic hepatitis, contain large amounts of prekeratin-like polypeptides which are assembled into a special form of fimbriated rods of 14- to 20-nm. filaments. These filaments are morphologically different from other forms of intermediate sized and thick filaments, including the prekeratin-containing 6- to 11-nm. tonofilament-like filaments present in various epithelial cells.

Animals↗
PubMed1979

Intermediate-sized filaments present in Sertoli cells are of the vimentin type.

The cytoplasmic structure of Sertoli cells of rat testes has been studied by electron microscopy of ultrathin sections. Sertoli cells contain numerous intermediate-sized (7-11 nm) filaments which form a meshwork extending throughout the whole cytoplasm. Often the frequency of such filaments appears especially high in juxtanuclear and cortical regions, including the apical recesses containing the spermatids. Examination of frozen sections of testes by indirect immunofluorescence microscopy using guinea pig antibodies to prekeratin and vimentin has shown the absence of intermediate-sized filaments of the cytokeratin type in all cells of the testes but the presence of filaments of the vimentin type in Sertoli cells as well as in cells of the interstitial space. These results show that the intermediate-sized filaments, abundant in Sertoli cells, are of the vimentin type. In addition we conclude that the "germ epithelium" differs from others true epithelia by the absence of cytokeratin filaments and typical desmosomes and, in Sertoli cells, the presence of vimentin filaments, suggestive of a mesenchymal character or derivation.

Animals↗