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Biomedical subjects

Y Katz

Publications and source records attributed to Y Katz.

At least 109 records · Page 6Linked to original sources
PubMed1990

Recurrent seizures in children with Shigella-associated convulsions.

Fifty-five children with Shigella-associated convulsions were followed prospectively to investigate their risk of subsequent febrile or nonfebrile seizures. The duration of the follow-up period was between 6.9 and 14.1 years (9.7 +/- 3.1 years). No case of nonfebrile seizures and only 2 cases (3%) of subsequent febrile seizures were observed during this period. We conclude that although febrile and Shigella-associated convulsions share many clinical features, the natural history of these two conditions seems to be distinctly different. Shigella-related convulsions are not associated with an increased incidence of subsequent febrile or nonfebrile convulsions.

Child↗
PubMed1990

Increased density of peripheral benzodiazepine-binding sites in ovarian carcinomas as compared with benign ovarian tumours and normal ovaries.

1. Benzodiazepines are involved in the control of proliferation and differentiation of normal and malignant cells in vitro. This regulatory ability is probably mediated via peripheral benzodiazepine-binding sites. 2. In the present study we compared the binding characteristics of peripheral benzodiazepine-binding sites in human epithelial ovarian carcinoma with those in benign ovarian tumours and normal ovaries. 3. The affinity and density of peripheral benzodiazepine-binding sites in homogenate preparations of ovarian carcinoma as compared with benign ovarian tumours and with normal tissues (used as controls) were determined using a ligand specific for peripheral benzodiazepine-binding sites, [3H]PK 11195, an isoquinoline carboxamide derivative. 4. We observed a robust (three- to five-fold) increase in the neoplasm compared with benign ovarian tumours and normal tissues, without a concomitant change in affinity values. 5. This finding may reflect a change in the metabolic rates of ovarian cancer which is expressed as the alteration in the density of peripheral benzodiazepine-binding sites.

Adenocarcinoma, Papillary↗
PubMed1990

Increase in peripheral benzodiazepine binding sites in colonic adenocarcinoma.

Binding characteristics of peripheral benzodiazepine binding sites (PBS) in membrane homogenates of samples taken at abdominal surgery from colonic adenocarcinoma and from healthy colonic tissues in 17 patients were determined. [3H]PK 11195, an isoquinoline carboxamide derivative, which exhibits high affinity to PBS, was used as a radioligand for the binding assay. A robust increase (3.1-fold) was found in membranes from the tumor sites as compared to normal control colon, whereas the affinity of [3H]PK 11195 to PBS was similar in both tissues.

Adenocarcinoma↗
PubMed1990

Nonreceptor-mediated responses of adenylate cyclase in membranes from liver, muscle, and white and brown adipose tissue of obese (fa/fa) and lean (Fa/) Zucker rats.

Adenylate cyclase activity was determined in membranes of liver, muscle, white adipose tissue, and brown adipose tissue (BAT) of lean (Fa/) and obese (fa/fa) Zucker rats. Responses were monitored following beta-adrenergic receptor stimulation and addition of GTP, GTP gamma S, or forskolin. beta-Adrenergic responses in liver, white adipose tissue, and BAT were lower in obese than in lean animals. No such difference was observed in muscle membranes. Production of cAMP after addition of guanine nucleotides was lower in liver and white adipose tissue membranes from obese rats compared with their lean littermates. Synthesis of cAMP in muscle membranes of obese animals after addition of GTP was either not different, or slightly higher, than that observed in muscle membranes from lean animals. Furthermore, production of cAMP after forskolin addition to muscle membranes of obese rats was significantly higher than that observed from lean rats under the same conditions. Interestingly, BAT membranes of obese rats were significantly more sensitive to guanine nucleotide activation than those of lean animals. The results confirm recent findings indicating inferior function of G proteins in liver plasma membranes of obese Zucker rats, and extend this observation to adipose tissue. The present results further suggest that the "nonreceptor" components (e.g., G proteins) responsible for the activation of adenylate cyclase in BAT membranes of obese rats are more responsive to stimulation than those of lean animals. Such sensitivity may be related to and perhaps compensate for the reduced thermogenic activity in the obese Zucker rat during the development of obesity.

Adenylyl Cyclases↗
PubMed1989

IL-1 and tumor necrosis factor. Similarities and differences in stimulation of expression of alternative pathway of complement and IFN-beta 2/IL-6 genes in human fibroblasts.

IL-1 and TNF induced concentration-related increases in the synthesis of factor B, C3, and IFN-beta 2/IL-6 in human skin fibroblasts. Effects of both stimuli were apparent with concentrations as low as 0.1 ng/ml and maximal responses were observed between 1 and 10 ng/ml; only for IL-1 induction of IFN-beta 2/IL-6 was there a further increase in response up to 100 ng/ml. For factor B and C3, maximal increases induced by IL-1 and TNF were similar: 119- and 109-fold for factor B and 15-fold and 11-fold for C3, respectively. Although both IL-1 and TNF increase synthesis of factor B and C3 in hepatocytes, the increases observed in fibroblasts were approximately 50- and 8-fold more for factor B and C3, respectively. Neither protein synthesis nor mRNA for IFN-beta 2/IL-6 was present in HepG2 cells either before or after stimulation with IL-1 or TNF. In contrast to the similarities between the effects of IL-1 and TNF on synthesis of factor B, C3, and IFN-beta 2/IL-6, only TNF increased synthesis of factor H. Because TNF induces membrane IL-1 in fibroblasts, it is possible to speculate that the effects of TNF on fibroblasts are due to induction of IL-1. An autocrine action of TNF through IL-1 is possible for TNF-induced synthesis of IFN-beta 2/IL-6, but the effects of TNF on synthesis of factor B, C3, and factor H indicated that TNF has effects on fibroblasts separate from IL-1. The effects of IL-1 and TNF on the synthesis of factor B and C3 in fibroblasts may be a part of an acute phase response occurring at a local level. However, the large responses in synthesis of factor B and C3 to IL-1 and TNF may suggest that factor B and C3 have a role, as yet undescribed, in tissues in addition to the role these proteins are known to play in inflammation.

Adult↗
PubMed1989

Ligands specific to peripheral benzodiazepine receptors for treatment of porphyrias.

Accumulating data indicate that porphyrins are physiologically endogenous ligands to mitochondrial peripheral benzodiazepine receptors. An isoquinoline carboxamide derivative that likewise binds to peripheral benzodiazepine receptors could prove therapeutically useful in porphyrias by displacing porphyrins from these receptors in mitochondria.

Humans↗
PubMed1989

Synthesis and regulation of C1 inhibitor in human skin fibroblasts.

Proteins of the C1 complex, C1q, C1r, and C1s, of the classical pathway of complement activation are known to be synthesized in human skin fibroblasts. Using metabolic labeling with [35S]methionine, immunoprecipitation, and SDS-PAGE, we demonstrate that human skin fibroblasts synthesize and secrete C1 inhibitor with an apparent molecular mass of 78 kDa in the cell lysate and 102 kDa in the extracellular medium. This C1 inhibitor had the capacity to bind activated C1s. Fibroblasts synthesized 30- to 50-fold more C1 inhibitor than was synthesized in monocytes. As previously reported, fibroblasts also synthesized C1r and C1s. IFN-gamma, IFN-beta 1, and TNF had significant, but distinct, effects on synthesis of C1 inhibitor, C1r, and C1s. Incubation of the cells with IFN-gamma, 1000 U/ml, for 24 h induced increases in the synthesis of C1 inhibitor, C1r, and C1s by 4.2-, 1.9- and 1.6-fold, respectively. IFN-beta 1 had effects similar to IFN-gamma, although smaller in magnitude. TNF, 12.5 ng/ml, induced increases in the synthesis of C1 inhibitor, C1r, and C1s by 1.5-, 1.4- and 2.6-fold. IL-1, IFN-beta 2 (IL-6), and LPS did not affect synthesis of C1 inhibitor, C1r, or C1s. Fibroblasts are present in large amounts in most tissues. Synthesis of C1 inhibitor, C1r, and C1s by these cells could provide a source of these important proteins in body tissues. In addition, fibroblasts should be a good model for the in vitro study of genetic diseases involving the synthesis of these proteins.

Adult↗
PubMed1989

[Delayed diagnosis of esophageal perforation].

Esophageal perforation is a rare complication of endotracheal intubation. Usually clinical symptoms are manifested shortly after the injury. Delayed diagnosis and treatment are associated with high morbidity and mortality. In a 38-year-old woman esophageal perforation was diagnosed 31 days after its occurrence, but prompt treatment, including surgery, led to a successful outcome. It is recommended that all available means be used to diagnose suspected cases of this fatal complication as early as possible.

Adult↗
PubMed1989

Interleukin 6 stimulates synthesis of complement proteins factor B and C3 in human skin fibroblasts.

Human interleukin (IL) 6 is a multifunctional cytokine which is synthesized by fibroblasts in response to many stimuli, including bacterial lipopolysaccharide (LPS). During acute-phase response, liver cells secrete a specific group of proteins among which components of the complement system and IL 6 appear to be an important mediator of this response. Human skin fibroblasts also synthesize at least seven proteins of the complement system. Each of these seems to be characteristically regulated by soluble mediators of the inflammatory process. Here we report that in fibroblasts, IL 6 induces increases in the rate of synthesis of factor B and C3, activator proteins of the alternative pathway of complement activation. The increases in factor B and C3 were concentration dependent reaching about 40- and 15-fold, respectively. The protein increases were observed within 4 h after IL 6 addition to the cells and were accompanied by increase in factor B and C3 mRNA. The data suggest that the induction of factor B and C3 by LPS may be mediated, at least in part, by IL 6 induced by LPS. This new function of IL 6 could provide a local protection against invading agents through activation of the antibody-independent alternative pathway of complement activation.

Blotting, Northern↗
PubMed1989

Laudanosine does not displace receptor-specific ligands from the benzodiazepinergic or muscarinic receptors.

The present study was designed to investigate whether D,L-laudanosine (a breakdown product of the neuromuscular relaxant atracurium besylate) interacts with benzodiazepinergic receptors or muscarinic receptors, both of which are involved in epilepsy and other types of seizures. The ability of D,L-laudanosine (10(-10) to 5 X 10(-5) M) to displace ligands specific for these receptors from their binding sites was tested. D,L-Laudanosine failed to inhibit the binding of [3H]flunitrazepam to central benzodiazepine receptors in the cerebral cortex, the binding of [3H]PK 11195 to peripheral benzodiazepine binding sites in the cerebral cortex and kidney, the binding of [3H]Ro 5-4864 to peripheral benzodiazepine binding sites in the kidney, or the binding of [3H]quinuclidinyl benzilate to muscarinic receptors in the cerebral cortex. These results suggest that laudanosine does not exert its convulsive effect via interaction with benzodiazepinergic or muscarinic receptors.

Animals↗
PubMed1989

Absence of peripheral-type benzodiazepine binding sites in renal carcinoma: a potential biochemical marker.

In an attempt to identify a tumour marker, we investigated peripheral-type benzodiazepine binding sites (PBS) in kidney specimens obtained from patients who underwent nephrectomy due to a renal mass. [3H]PK 11195, an isoquinoline carboxamide derivative, was used as a ligand. Binding assays were conducted on samples of membrane homogenate taken from both the healthy portion and the tumour site of the kidney. It was found that binding characteristics of benign tumours and normal kidney tissues were not significantly different, i.e. equilibrium dissociation constants of 2.20 +/- 0.73 and 2.38 +/- 0.98 nM, respectively, and maximal number of binding sites of 3190 +/- 1081 and 4189 +/- 998 fmol/mg protein, respectively. In contrast, no PBS were detectable in renal carcinoma. The absence of PBS in malignant renal tissues may serve as a biochemical marker for tumours of the kidney.

Adenoma↗
PubMed1989

Induction of anesthesia with propofol in urological outpatient surgery.

Propofol (Diprivan) in a new formulation, a short-acting intravenous anesthetic, was used as an induction agent for short urological procedures. Forty unpremedicated patients were treated with either propofol or thiopental in a randomized study. The onset of anesthesia and duration of apneic period were prolonged and the decrease in systolic blood pressure was more profound in the propofol group. Heart rate was less stable and recovery time was longer in the thiopental group. Other parameters, such as quality of anesthesia, acceptability of the drug or rate of side effects, were similar in both groups. These results suggest that propofol in a new formulation is a suitable agent for short urological procedures in outpatient surgery.

Adult↗
PubMed1989

Adrenal myelolipoma simulating virilizing adrenal tumor.

We describe a case of adrenal myelolipoma that simulated clinically and biochemically a virilizing adrenal tumor. The tumor was removed surgically. The preoperative diagnosis of adrenal myelolipoma can be made by the characteristic appearance on ultrasonography, computerized tomography and in equivocal cases by guided needle biopsy.

Adenoma↗
PubMed1989

Elevated serum creatine kinase. Following febrile seizures.

Serum creatine kinase (CK) was determined in 52 children admitted following an episode of febrile convulsions. Enzyme levels correlated with the estimated duration of the seizure. Twenty-four hour values were significantly higher than those observed 1 hour after the convulsive episode. Serum CK levels are frequently used for diagnostic purposes, so the questionable validity of this test when drawn after a convulsive episode must be considered.

Age Factors↗
PubMed1989

Neural and behavioral alterations after early exposure to phenobarbital.

Mice who were exposed to phenobarbital prenatally (B mice) had at adulthood deficits in the hippocampal eight-arm maze, spontaneous alternations, and water maze behaviors. Morphological studies revealed neuronal losses in the hippocampus. The surviving neurons had reductions from control in the number of dendritic branches, area and spine density, but wider fission angle than control. Neurochemical studies on the hippocampus revealed the following alterations: (a) decrease in NE level and the number of the NE cell bodies (b) no change in the serotonergic system (c) an increase in muscarinic receptors Bmax in the hippocampus; (d) no changes in GABA and benzodiazepine receptors. However, neonatal phenobarbital exposure caused an increase in the Bmax of GABA and benzodiazepine receptors. Transplantation of fetal septal cholinergic neurons into the hippocampus of B mice reversed most of the deficits in eight-arm maze behavior, while transplantation of noradrenergic cells did not affect the performance of B mice. In further studies on cholinergic mechanisms, the dopaminergic innervations in the septum (originating from A10), which are known to indirectly inhibit the activity of the septohippocampal cholinergic pathways, were destroyed by 6-OHDA. B mice treated with 6-OHDA had an increase in hippocampal ChAT activity and improved their eight-arm maze performance. Thus, understanding of the mechanism of a particular behavioral deficit enables one to correct it despite the nonspecific action of the neuroteratogen.

Animals↗