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Biomedical subjects

M Freund

Publications and source records attributed to M Freund.

At least 325 records · Page 18Linked to original sources
PubMed1979

[(Meningeal carcinomatosis in patients with breast cancer)].

Four cases of breast cancer with meningeal involvement are presented and a review of the literature is given. Post mortem examination of patients with malignant epithelial tumors shows meningeal carcinomatosis in less than 1%. In these solid tumors breast cancer is the most common primary site. The mode of tumor spread to the leptomeninges is not yet decisively known. Clinical symptoms and findings can be divided concerning three anatomic areas: cerebral, cranial nerve and spinal root. Slow onset of clinical symptoms and findings as well as their mixed pattern is generally noticed. Characteristic findings in cerebrospinal fluid are increased protein content, hypoglycorrhachia and identification of malignant cells. Other laboratory tests are generally of no diagnostic value. In some cases myelogram shows typical alterations. The value of computerized tomography in meningeal carcinomatosis remains to be solved. The following treatment for meningeal carcinomatosis by breast cancer can be recommended: Intrathecal methotrexate 0.2 mg/kg every 3 or 4 days until improvement of symptoms and laboratory findings in cerebrospinal fluid, followed by radiation of the clinically most involved areas and maintenance therapy with intrathecal methotrexate or systemic BCNU.

Adult↗
PubMed1979

The effect of theophylline and dibutyryl cyclic AMP on the uptake of radioactive calcium and phosphate ions by boar and human spermatozoa.

Radioactive calcium uptake by suspensions of washed boar and human spermatozoa was inhibited by the mitochondrial uncoupling agent carbonylcyanide-p-trifluoromethoxy-phenylhydrazone (FCCP). Theophylline + dibutyryl cyclic AMP also inhibited calcium uptake in the presence or absence of FCCP. Uptake of low concentrations of calcium (0 . 1 mM) was inhibited by the calcium ionophore A23187, but at high calcium concentrations the ionophore stimulated calcium uptake. These observations are explained in terms of a mechanism for the regulation of calcium uptake in spermatozoa based on competing mitochondrial and plasma membrane pumps. Uptake of 32P was also inhibited. These effects provide evidence that cyclic AMP plays a role in the transport of ions across the plasma membrane of spermatozoa.

Animals↗
PubMed1978

Isolation and characterization of membrane vesicles from human and boar spermatozoa: methods using nitrogen cavitation and ionophore induced vesiculation.

A method for isolation of plasma membrane vesicles from human and boar spermatozoa using nitrogen cavitation is described. The purity of the preparations were assessed by electron microscopy, marker enzyme assay and the sedimentation characteristics of fused plasma membrane-acrosomal membrane vesicles in sucrose gradients. PAGE-SDS profiles of plasma membrane polypeptides from boar spermatozoa were significantly different from those of human spermatozoa. Differences in electrophoretic profiles of polypeptides from different regions of the spermatozooon were also observed.

Acrosome↗
PubMed1978

The meiotic behavior of triploidy in a human 69,XXX fetus.

Meiotic studies were made on the fetal ovaries of a triploid fetus, 69,XXX. The association modalities of the three chromosomes in human triploidy are the same as those described in several plant species; i.e., trivalents, bivalents and univalents can be found in the same nucleus. In most cases of trivalent configuration, the association occurs between pairs.

Azure Stains↗
PubMed1977

Reversible inhibition of the motility of human spermatozoa by cytochalasin B.

Cytochalasin B inhibits the motility and metabolism of washed human spermatozoa at low concentrations (20 to 200 mum). Spermatozoal motility (primarily the frequency of flagellar contraction) declines slowly after addition of the antibiotic but is not abolished even after treatment for several hours. The addition of caffeine or dibutyrylcyclic adenosine 3' :5'-monophosphate to washed sperm suspensions increases the percentage of motile cells, the frequency of flagellar contraction, and the rate of glycolysis. These effects are blocked by cytochalasin B. However, cytochalasin B-treated spermatozoa regain their responsiveness to these agents when the antibiotic is washed out of supporting media. These effects are discussed in terms of an interaction of cytochalasin B with the sperm plasma membrane.

Bucladesine↗
PubMed1976

Relationship between motility and the transport and binding of divalent cations to the plasma membrane of human spermatozoa.

Measurements of fluorescence changes of the divalent cation probe chlortetracycline, which accumulates in the plasma membrane of human spermatozoa, and measurements of radioactive calcium uptake indicate that the plasma membrane of human spermatozoa is impermeable to calcium. Moreover, permeability to exogenous calcium is not changed when sperm motility is stimulated by agents which increase intracellular levels of adenosine 3':5'-monophosphate (cyclic AMP). Evidence is presented, however, which suggests that energy-dependent divalent cation binding to the plasma membrane is lowered when motility is increased by cyclic AMP phosphodiesterase inhibitors.

Calcium↗
PubMed1976

Reversible inhibition of the motility of human spermatozoa by tetraphenylboron.

The motility of washed suspensions of human spermatozoa was completely inhibited by tetraphenylboron at concentrations that had little effect on sperm energy metabolism. The inhibition of motility was reversed by quaternary ammonium salts, albumin, caffeine, dibutyryl cyclic AMP and potassium ions. The addition of ouabain to cells redndered immotile by tetraphenylboron prevented reinitiation of motility by potassium but not by the other compounds. These observations, together with the effect of tetraphenylboron on the fluorescence of sperm suspensions treated with 1-anilinonaphthalene 8-sulphonic acid, suggest that the binding of tetraphenylboron to sites on the sperm plasma membrane is involved in the inhibition of sperm motility and the cyclic AMP may be involved in the regulation of ion transport across the plasma membrane.

Adenosine Triphosphate↗
PubMed1976

In vitro effect of thymosin on T cells from immunodepressed surgical patients.

In preparation for the use of bovine thymosin, a thymic hormone, as a specific T cell stimulator in immunodepressed patients, we studied its effect on E rosette formation of peripheral lymphocytes from patients with (1) advanced malignancies, (2) extensive burns, and (3) septicemia. E rosette formation in vitro with and without thymosin was evaluated in 52 patients with carcinoma of the breast (25) or lung (27) in relation to adjuvant therapy and/or surgery. The depression of E rosettes in cancer patients was most striking when adjuvant therapy, irradiation, and/or chemotherapy were used; in 20 patients this was elevated by incubation with thymosin. There was a delay in recovery of depressed E rosette levels after radical mastectomies in four patients, recovery being accelerated by thymosin. In ten burn patients (40 to 80 percent of body surface area, second and third degree burns), the depression in E rosette levels occurred in the first week and was most marked in 3 to 4 weeks. In eight patients this was elevated by thymosin in vitro. In four septic patients, all undergoing operation, serial studies suggested that recovery from sepsis was accompanied by spontaneous rise in E rosette levels. This process was accelerated by thymosin in vitro. This study as well as previous experiments with animals suggest that thymosin may influence depressed host resistance favorably by increasing T-cell-mediated immunity.

Adolescent↗
PubMed1975

Oxidative and glycolytic metabolism of semen components by washed guinea pig spermatozoa.

The concentration of several potentially metabolizable substances in guinea pig semen and the ability of these substances to support ATP synthesis and the motility of guinea pig sperm have been determined. Both glucose and fructose were present in high concentration in semen and were equipotent at the concentration tested in maintaining high levels of ATP and a high rate of motility. Lactic and pyruvic acids also supported a high rate of sperm motility but maintained lower levels of ATP. These constituents of guinea pig semen, as well as the metabolites alpha-glycerophosphate, succinic acid, and beta-hydroxybutyric acid, are oxidized at unusually high rates. The active oxidative metabolism of guinea pig sperm is compared with that of human sperm which is primarily glycolytic.

Adenosine Triphosphate↗
PubMed1975

[Plasma histamine levels in man following infusion of hydroxyethyl starch: a contribution to the question of allergic or anaphylactoid reactions following administration of a new plasma substitute (author's transl)].

In contrast to the effects of rapid infusion of gelatin and dextran preparations, no histamine release was observed in 10 human subjects (volunteers) following rapid infusion of hydroxyethyl starch. This was measured by fluorometric histamine determination in venous plasma. Furthermore no clinical symptoms of an allergic or anaphylactoid reaction could be detected in any of the volunteers.

Adult↗