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Biomedical subjects

W Gevers

Publications and source records attributed to W Gevers.

At least 73 records · Page 4Linked to original sources
PubMed1979

The histochemical behaviour, electrophoretic mobility and distribution in cell fractions of acid phosphatase isozymes in prostatic cancer and benign prostate hyperplasia.

Acid phosphatase isozymes were investigated in cancerous prostatic tissue (4 cases) and benign prostatic hyperplasia (6 cases). Electron-microscopic histochemical examination of cancer tissue revealed irregular acid beta-glycerophosphatase staining in various cell organelles, including the plasma membrane, which was not seen in non-malignant tissue. Cancerous tissue homogenates also contained isozymic acid phosphatase species with high electrophoretic mobility, which was not detectable in benign tissue unless treated with detergent. Fractionation by differential centrifugation confirmed that much of the acid phosphatase activity in cancer tissue was extra-lysosomal. The detection of these isozyme properties may provide an opportunity, by means of tissue investigations, to define tumour stages earlier than on the basis of increased levels of serum acid phosphatase activity indicative of stage IV (D) prostatic cancer.

Acid Phosphatase↗
PubMed1979

Glycoprotein, elastin, and collagen secretion by rat smooth muscle cells.

Smooth muscle cells from rat heart secreted extracellular matrix components at high rates for many generations in culture. The matrix proteins remained anchored to the culture dish and were characterized after removal of cellular material with sodium dodecyl sulfate. Sequential enzyme digestion demonstrated the presence of at least three components, including glycoprotein(s), elastin, and collagen. Prolonged extraction of the matrix with detergent under reducing conditions solubilized a fucosylated glycoprotein having an apparent molecular weight of 250,000 and two other proteins with molecular weights of 72,000 and 45,000, respectively. Sublines derived from discrete colonies of smooth muscle cells synthesized all of the matrix components, and the proportion of collagen secreted by some sublines increased with time in culture. The biosynthesis of a mixed extracellular matrix and the relationships among the component proteins were therefore studied in one system producing milligram quantities of material.

Animals↗
PubMed1979

Electrophoretic evaluation of different hormonal receptor sites in the prostate during anti-hormonal treatment and in response to hormones.

Physical separations of different receptor entities by gradient ultracentrifugation or by separations based on ionic strength are interfered with, either by contamination with non-specific binding sites or they are irrelevant because of the low yield of sites after processing. Electrophoretic separation may give a better resolution because of the different nett charges on SHBG and the specific receptors. Isoelectric microfocussing allows the additional differentiation of sites based on the individual isoelectric points of each entity. Using this method, differentiation of at least three different sites in prostate tissue has been achieved.

Humans↗
PubMed1978

The diagnostic value of lysosomal enzyme patterns in bronchial aspirates of patients with suspected bronchial carcinoma.

The measurement of the activity of acid hydrolases and of alkaline phosphatase in bronchial aspirates obtained through bronchoscopic procedures from a series of 300 patients forms the basis for a screening program to diagnose bronchial malignant neoplasms more effectively. We define such a screening test as one permitting rapid measurements indicative of pathologic abnormalities and producing a preliminary diagnosis which, if in error, yields preferably a false-positive result. Using this approach, we demonstrated that an elevation of the activity of alkaline phosphatase or cathepsin D predicts a 50 percent likelihood of cancer, but elevation of both the concentrations of alkaline phosphatase and cathepsin D has an additive prediction of 71 percent. Data obtained in this study showed that the presence of a pulmonary tumor can cause increased levels of alkaline phosphatase or cathepsin D (or both) in bronchial aspirates before the presently accepted methods yield a diagnostic result. Furthermore, those patients with an elevated activity of alkaline phosphatase or cathepsin D (or both) but with no histologically demonstrable pulmonary carcinoma can be reexamined intermittently.

Acid Phosphatase↗
PubMed1977

Effects of 5-bromo-2'-deoxyuridine on beating heart cell cultures from neonatal hamsters.

1. Primary heart cell cultures from neonatal hamsters yielded a heterogeneous cell population, containing muscle cells undergoing progressive differentiation, as well as non-muscle cells. 2. Addition of 5-bromo-2'-deoxyuridine, at an early stage, to such cultures enhanced the formation of beating sheets of differentiated muscle cells. Accumulation of myosin heavy chains and creatine kinase also occurred in the presence of the analogue. 3. To obtain these effects, the analogue had to be added during the initial rapid growth phase of the cells. Division of the treated cells then ceased when the cell numbers had approximately doubled. 4. Similar results were obtained with other inhibitors of DNA synthesis. Thus improved muscle cell cultures can be obtained by preventing non-muscle cells from overgrowing the cultures. 5. One effect caused only by 5-bromo-2'-deoxyuridine was a large increase in the Ca2+-stimulated ATPase (adenosine triphosphatase) activity which sedimented at low ionic strength. This increase was not due to a greater content of myofibrillar myosin, or to myosin isoenzyme changes, because purified myosin prepared from treated and untreated cultures did not exhibit the increased Ca2+-stimulated ATPase activity.

Adenosine Triphosphatases↗
PubMed1977

5-bromo-2'-deoxyuridine-stimulated calcium ion- or magnesium ion-dependent ecto-(adenosine triphosphatase) activity of cultured hamster cardiac cells.

1. Treatment of hamster heart cells in primary culture with 5-bromo-2'-deoxyuridine resulted in the greatly increased activity of a particulate Ca2+- or Mg2+-dependent ATPase (adenosine triphosphatase). 2. 5-Bromo-2'-deoxyuridine exerted these effects only when it was incorporated into cellular DNA, and then in a concentration-dependent manner. 3. Serially replated cells contained less of the activity (expressed as a function of total cell protein) than did the primary cultures, but the stimulation caused by 5-bromo-2'-deoxyuridine addition was much greater. 4. The affected enzyme was apparently localized in the plasma membrane of the cells with its active centre exposed to the outer environment [ecto-(ATPase) dependent on Ca2+ or Mg2+].5. The activity was unaffected by treatment with p-chloromercuriphenylsulphonate, ouabain andverapamil. 6. Ecto (5'-nucleotidase) activity was not increased by 5-bromo-2'-deoxyuridine treatment of cells, and ecto-(p-nitrophenyl phosphatase) activity was only slightly enhanced.

Adenosine Triphosphatases↗
PubMed1975

[Lactate dehydrogenase isoenzymes in the growth of heart cells].

As part of a detailed biochemical study of developing and growing heart cells, the protein- or cell-specific activities of lactate dehydrogenase isozymes were determined in cultured neonatal hamster heart cells and in intact hearts of hamster embryos and neonates. Evidence for differentiative growth of heart cells in both systems was obtained, but the characteristic in vivo isozyme shift from species rich in M subunits to those containing mainly H subunits was reversed in the cultured cells, suggesting that controls normally determining this pattern change might be absent in the conditions of in vitro cultivation.

Animals↗
PubMed1975

Catecholamine release as mediator of intracellular enzyme activation in ischaemic perfused rat hearts.

Isolated rat hearts perfused at suboptimal pressures have been studied as a model for generalised myocardial ischaemia. Glycogen phosphorylase a and hormone-sensitive triglyceridase activities, measured as markers for endogenous catecholamine release, were significantly increased at low perfusion pressures. Pharmacological blockage of noradrenaline re-uptake accentuated these effects, and depletion of catecholamine reserves eliminated them. This phenomenon may be important in the pathophysiology of cardiac ischaemia and its serious complications.

Animals↗