Interleukin-1-β and Tumor Necrosis Factor-α Increase Peripheral-Type Benzodiazepine Binding Sites in Cultured Polygonal Astrocytes

Peripheral-type benzodiazepine binding sites (PTBBS) are markedly increased in the injured CNS. Astrocytes appear to be the primary cell type which express increased PTBBS. Because certain cytokines within the injured CNS are potent mitogens for astrocytes, we examined the effects of two such cytokines, interleukin (IL)-1 beta and tumor necrosis factor (TNF), on PTBBS in cultured astrocytes using [3H]Ro 5-4864 as the specific ligand. Purified cultures of either polygonal or process-bearing astrocytes were prepared from neonatal rat cerebral hemispheres. At a concentration of 1.8 nM, specific binding of the radioactive ligand to polygonal astrocytes reached equilibrium within 60 min and was half-maximal by 5-10 min. By contrast, specific binding to process-bearing astrocytes barely exceeded background levels. IL-1 and TNF increased PTBBS within polygonal astrocytes in both dose- and time-dependent manners. At 10-50 ng/ml, IL-1 beta and TNF-alpha elevated [3H]Ro 5-4864 binding in polygonal astrocyte cultures 65 and 87%, respectively, above the level in control cultures. However, no changes in PTBBS were seen within polygonal astrocytes after IL-2 treatment. Scatchard analysis of saturation binding experiments suggested that the increase in PTBBS promoted by TNF was due to an increased number of binding sites present in polygonal astrocytes and not due to an increase in receptor affinity. Binding data suggested that PTBBS within cultures of process-bearing astrocytes were virtually absent irrespective of the treatment. These in vitro data suggest that certain cytokines found in the injured brain may be involved in up-regulating PTBBS within a particular subtype of astrocyte.     

Anaerobic biodegradability of polyvinyl alcohol

Summary Biodegradability of polyvinyl alcohol (PVA) under anaerobic conditions was demonstrated using anaerobic river sediments and anaerobically treated activated sludge from a sewage treatment plant. PVA having molecular weights of 2000 and 14000 was over 60% biodegraded as determined by TOC.     

Single amino acid replacements affecting the thermostability of kanamycin nucleotidyltransferase

Summary Amino acid residues of the carboxyl-terminal region of kanamycin nucleotidyltransferase were modified using segment-directed mutagenesis. Six different mutant enzymes with single amino acid replacements were selected out of 59 clones by DNA sequence analyses. The mutant enzymes were purified and it was found that the thermostability of one mutant enzyme was identical to the wild type, whereas the other five were less thermostable at varying degrees. The data suggested that changes in the enzyme thermostability depend not only on the position but also on the species of amino acid residue replaced.     

Correlation of in vitro properties of Rhodococcus (Corynebacterium) equi with virulence for mice

To study the virulence of Rhodococcus (Corynebacterium) equi, seven ATCC strains of different serotypes were tested for their LD50 in mice, clearance of the organism from the lungs and spleen following intravenous or intratracheal inoculation, and in vitro interaction with murine peritoneal macrophages. Strains ATCC 33704 and 33705 were virulent for mice and multiplied in the lungs and spleen, resulting in death of the animal in 5 days. The other five strains were avirulent for mice. The number of bacteria in the lungs and spleen of mice given these five strains decreased immediately. Pulmonary clearance of strains ATCC 33703, 33706, and 33707 was significantly more rapid than that of the virulent strains ATCC 33704 and 33705 12 hr after inoculation. Complete clearance of the avirulent strain ATCC 33707 occurred by day 14, while that of virulent ATCC 33704 and 33705 strains occurred by day 30. The virulent strains ATCC 33704 and 33705 were resistant not only to phagocytosis but also to intracellular killing by macrophages. Strains ATCC 33702 and 33706 were rapidly killed by macrophages although they were rather resistant to phagocytosis. Strain ATCC 33703 was easily phagocytized though resistant to killing by macrophages. The most avirulent strains, ATCC 33707 and 6939, were easily phagocytized and rapidly killed by macrophages. These results indicate that virulence appeared to be related to the ability of the organisms to resist clearance from the lungs and spleen and to resist phagocytosis and intracellular killing by macrophages.     

Praziquantel-induced secretion of proteolytic enzyme from Schistosoma mansoni cercariae

The effect of praziquantel (PZQ) on secretion of proteolytic enzyme by Schistosoma mansoni cercariae was examined using an azocoll assay. The cercariae secreted proteolytic enzyme in various concentrations of PZQ (0.1, 1, and 10 micrograms/ml), but secretion of enzyme was highest at the lowest concentration. PZQ-induced secretion of proteolytic enzyme was partially inhibited by treatment with verapamil and ethylene glycol-bis(beta-aminoethyl ether)N,N,N',N'-tetra-acetic acid but not by calmodulin antagonist W-7 and protein kinase C inhibitor H-7.     

Non-invasive detection of malignancy by identification of unusual CD44 gene activity in exfoliated cancer cells.

OBJECTIVE--To investigate non-invasive detection of cancer by testing for unusual CD44 gene activity in a clinical sample as an indicator of exfoliated tumour cells. DESIGN--Case-control study. SUBJECTS--44 unselected, consecutive patients with bladder cancer and 46 people with no evidence of neoplasia. MAIN OUTCOME MEASURE--Presence or absence of large CD44 gene products containing exon 6 derivatives in urine samples. RESULTS--Novel abnormalities in the pattern of expression of this gene, seen specifically in tumour tissue, led to cloning of a newly recognised coding region in it (exon 6). This was tested as a probe for detection of exfoliated malignant cells in naturally voided urine. CD44 gene products extracted from the urine and amplified with polymerase chain reaction contained predicted electrophoretic band of 735 base pairs in 40 of the 44 patients with bladder cancer (sensitivity 91%). Products from 38 of the 46 people with no evidence of neoplasia showed no such band (specificity 83%). CONCLUSIONS--Unusual activity of the CD44 locus in neoplasia and malignancy is confirmed, and techniques for the analysis of such activity can enable non-invasive investigation of patients for primary or recurrent bladder cancer or for other tumours that shed neoplastic cells into body fluids.     

DDT inhibition of Ca-Mg ATPase from peripheral nerves and muscles of lobster, Homarus americanus

Sensitivity of CaMg ATPase from axonic plasma membrane (APM) and sarcoplasmic reticulum (SR) of lobster, $\text{Homarus}\text{,}\text{americanus}$, to DDT was studied. The CaMg ATPase found in SR with the high Ca²⁺ affinity is sensitive to DDT while the portion of ATPase related to the low Ca²⁺ affinity site is not inhibited by DDT. Also, DDT is more inhibitory against the CaMg ATPase prepared from APM than the one obtained from SR. The relationship between inhibition of the CaMg ATPase by DDT in the axonic nerve membrane and $\text{in}\text{,}\text{vivo}$ poisoning symptoms of the nervous system is discussed.