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Biomedical subjects

J Glick

Publications and source records attributed to J Glick.

At least 55 records · Page 3Linked to original sources

The intracellular localization of Pseudomonas aeruginosa lectins.

The localization of the Pseudomonas aeruginosa lectins (PA-I and PA-II) was studied using methods of osmotic shock, freezing and thawing and spheroplast formation. Very slight release of the two lectins occurred when P. aeruginosa was exposed to magnesium-osmotic shock or was frozen and thawed. Under these conditions, release of the periplasmic 5'-nucleotidase occurred, whereas no release of cytoplasmic glucose-6-phosphate dehydrogenase activity was detected. Formation of spheroplasts from P. aeruginosa by gradual removal of the bacterial envelopes revealed low lectin activity in the treatment fluids. Osmotic shock treatment of the lysozyme treated mureinoplasts resulted in low release of glucose-6-phosphate dehydrogenase and the two lectins (10-13%) and a considerable activity (38.4%) of 5'-nucleotidase. The presence of the lectins on the outer and the cytoplasmic membranes enabled intact cells and spheroplasts of P. aeruginosa to agglutinate papain-treated human erythrocytes. These results indicate that the two lectins are located mainly in the cytoplasm with small fractions on the cytoplasmic and outer membranes and in the periplasmic space.

5'-Nucleotidase↗

The 2.5 A crystal structure of a dimeric phospholipase A2 from the venom of Crotalus atrox.

The crystal structure of the dimeric (alpha 2) phospholipase A2 from Crotalus atrox has been determined by multiple isomorphous replacement to 2.5 A resolution. A skeletal model was fit to the electron density, and the stereochemistry of the backbone was idealized. The dimeric molecule is a well defined oblate ellipsoid composed of two covalently identical subunits related by a local dyad axis which is essentially "exact" except for deviations at the periphery induced by ionic lattice contacts with neighboring dimers. As expected, the basic architecture of the individual protomers is similar to the structure of the homologous monomeric bovine enzyme (Dijkstra, B. W., Drenth, J., Kalk, K., and Vandermaalen, P. J. (1978) J. Mol. Biol. 124, 53-60). The intramolecular contact surface between the protomers is extensive and involves the catalytic and calcium-binding sites. Access to an internal cavity formed by the enclosed and abutting active center regions is quite restricted. The putative interfacial recognition surfaces of each protomer are exposed to the solvent but are on opposing surfaces of the ellipsoid, suggesting that both of these regions cannot interact with the same membrane surface simultaneously unless the membrane is distorted from planarity and/or the dimer is significantly modified.

Amino Acid Sequence↗

Interactions of Pseudomonas aeruginosa lectins with Escherichia coli strains bearing blood group determinants.

Pseudomonas aeruginosa lectins interact with Escherichia coli strains O86B7 and O128B12, which possess B and H (O) blood group determinants, respectively. The interaction could be demonstrated by specific agglutination of the bacteria, by haemagglutination inhibition tests and by lectin-mediated peroxidase binding to the bacteria. The agglutination of E. coli O86B7 by the Pseudomonas galactose-binding lectin was inhibited by D-galactose and by the lipopolysaccharide extracted from E. coli O86B7. Similarly, the specific agglutination of E. coli O128B12 by the Pseudomonas mannose-binding lectin (which also binds L-fucose, L-galactose and D-fructose) was inhibited by D-mannose, L-fucose, L-galactose and D-fructose, as well as by athe lipopolysaccharide extracted from E. coli O128B12. The interaction between E. coli O128B12 and the Pseudomonas mannose-binding lectin was also demonstrated by lectin-mediated peroxidase binding to the bacterial surface. Peroxidase binding was also inhibited by the above-mentioned sugars and E. coli O128B12 lipopolysaccharide. Treatment of cells of the two E. coli strains with protein-denaturing agents did not reduce their agglutination by the Pseudomonas lectins. On the other hand, oxidation of the cell surface sugars by sodium metaperiodate or boiling the cells in the presence of 1% acetic acid for 1 h abolished their agglutination by the two lectins. It is, therefore, suggested that the Pseudomonas lectins interact with the B and H (O) blood group determinant sugars (D-galactose in E. coli O86B7 and L-fucose in E. coli O128B12) residing in the lipopolysaccharides of these E. coli strains.

ABO Blood-Group System↗

Lectin-bearing protoplasts of Pseudomonas aeruginosa induce capping in human peripheral blood lymphocytes.

The redistribution of surface membrane receptors and cap formation by pseudomonas aeruginosa lectins (Ps-GAL, which binds D-galactose, and Ps-MAN, which binds D-mannose and L-fucose) was studied in human peripheral blood lymphocytes by scanning electron microscopy. When Ps-GAL and Ps-MAN-bearing protoplasts of Pseudomonas aeruginosa were incubated with lymphocytes, cap formation was revealed by the accumulation of protoplasts at one pole of the lymphocyte. No adherence or capping was observed when intact Pseudomonas aeruginosa cells were used. Pretreatment of the lymphocytes by papain or neuraminidase did not enhance the capping. No capping or adherence of protoplasts to lymphocytes was observed in the presence of D-galactose, while addition of D-mannose had no effect. The inhibitory effect of D-galactose on the adherence and capping in human peripheral lymphocytes by Pseudomonas aeruginosa protoplasts suggests that the Ps-GAL lectin is responsible for both phenomena.

Galectins↗

Adriamycin plus vincristine alone or with dibromodulcitol or ICRF-159 in metastatic breast cancer.

A total of 268 patients with metastatic breast cancer were prospectively randomized to receive Adriamycin-vincristine (AV) alone, AV plus dibromodulcitol (AVD), or AV plus ICRF-159 (AVI). Two hundred thirty were eligible and had received prior chemotherapy. The objective response rates were 27%, 23%, and 16% for AV, AVD and AVI, respectively, and an additional 44% had stabilization of disease. Duration of responses ranged from 4.1 to 4.6 months and the times to treatment failure from 2.9 to 3.8 months. Median survivals ranged from 7.1 to 8.3 months. Performance status and the presence of liver or brain metastases were significant prognostic variables for outcome. These studies show that AVI is inferior to AV with respect to survival when prognostic variables are taken into account in a multivariate model, whereas AVD which utilizes a lower dose of Adriamycin appears to have comparable antitumor activity to AV. This does not appear to offer any benefit to patients previously treated with chemotherapy, as in this trial, but it may be an advantage to previously untreated patients since Adriamycin can be administered to responding patients over a longer period of time before an unacceptable total cumulative dose is reached.

Aged↗

VM-26, a new anticancer drug with effectiveness in malignant lymphoma: an Eastern Cooperative Oncology Group Study (EST 1474).

Thirty-six patients with stage III and IV Hodgkin's disease and non-Hodgkin's lymphoma, who had become refractory to conventional chemotherapy, were treated with VM-26. Complete remissions were documented in two patients with diffuse histiocytic lymphoma. Six patients (four with non-Hodgkin's lymphomas and two with Hodgkin's disease) had partial remissions. The overall response rate was 22% (eight of 36 patients). Hematologic toxicity was the most frequent dose-limiting toxicity. Nonhematologic toxic effects were mild and acceptable. This study demonstrates that VM-26 can produce tumor responses in refractory lymphomas. The Eastern Cooperative Oncology Group is currently planning two new phase II studies to incorporate VM-26 with other active new agents, one involving hexamethylmelamine and the other involving cis-dichlorodiammineplatinum(II).

Adult↗

Educational intervention for preschool children in a pediatric clinic.

A parent education program aimed at promoting cognitive development in 2- and 3-year-olds was instituted in both a pediatric clinic of a general hospital and a child health station in the community. Parent participants were asked to work at home daily with their children using age-graded play materials supplied by the program. They were tutored individually, in the clinic playroom, by bilingual playroom assistants using role-playing techniques. One hundred fifty children completed the program out of a total of 468. Subjects were tested before and after training on the Cattell: Stanford-Binet and showed a positive gain in performance. Parents reported that their program experiences made them aware of their ability to teach their children. This was reflected in their changing view of the children's activities which were previously seen as aimless and "bad" and were now viewed as constructive and amenable to modification by the parents.

Child Development↗

Linguistic structure and transposition.

Transfer of a learned discrimination along the size dimension was studied in groups of American and African tribal children. The language spoken by the African children contains an asymmetry in the expression of size comparisons that is not present in English. Contrary to theories of linguistic mediation of choice behavior, transfer choices were not related to the differing linguistic patterns; however, initial choices and post-test descriptions of choices were so related.

Child↗

Abnormal diurnal weight gain among long-term patients with schizophrenic disorders.

We found diurnal weight gain to be abnormal among 65 long-term patients with schizophrenic disorders. Patients were weighed at 7 a.m. and 4 p.m. serially and diurnal weight gain was normalized (NDWG) as a percentage by subtracting the 7 a.m. weight from the 4 p.m. weight, multiplying the difference by 100, and then dividing the result by the 7 a.m. weight. NDWG was 2.2 +/- 1.5% for 47 male patients compared (P = 0.001) with 0.6 +/- 0.4% for 11 male controls. NDWG was 1.7 +/- 0.7% for 18 female patients compared (P less than 0.0001) with 0.5 +/- 0.3% for 14 female controls. We hypothesize that NDWG may be an index of both the severity and duration of the schizophrenic disorder.

Adult↗