Efficacy of praziquantel treatment of schistosomiasis in a non-endemic country: a follow-up of parasitological, clinical and immunological parameters.

Schistosomiasis patients were immigrants to Czechoslovakia from Angola and Yemen. Most of them had light or moderate infections and felt subjectively healthy. They received treatment with praziquantel (two doses with a total of 40 mg/kg) and were followed up for several years. In nine of 13 patients, Schistosoma haematobium or S. mansoni eggs with undamaged miracidia were detected in biopsies from the bladder or the rectum one year or later after treatment. Granulomatous reactions in the rectum and bladder lesions of stage 1 including thickened bladder walls persisted in most of the patients. Antibody levels against adult S. mansoni worm antigen remained elevated for at least two years after therapy in some patients and declined in others. Among the nine patients, for whom pre- and post-treatment sera were available, the changes in relative levels of antibodies did not strictly correlate with the continued presence of schistosome eggs in, or their absence from, biopsies. We discuss the results obtained with sensitive diagnostic techniques in the absence of subjectively perceived disease.     

Zweiter Beitrag zur Flora Montenegro's

Ohne Zusammenfassung     

A successive histochemical staining for succinate dehydrogenase and "reversed"-ATPase in a single section for the skeletal muscle fibre typing

A procedure is described which simplifies the classification of skeletal muscle fibres in that it allows a simultaneous evaluation of both the oxidative capacity and the intensity of "reversed" ATPase of the fibres, and thus enables to distinguish three fibre types - SO, FOG and FG - in one tissue section. After preincubation at pH 4.1-4.2 the cryostat section is incubated for succinate dehydrogenase (SDH) and subsequently for "reversed"-ATPase. This is followed by the fixation with neutral buffered formaldehyde. The results of typing of chicken, minipig and rabbit fibres in a single muscle section stained with this technique are identical to those obtained with the usual method based on a comparison of serial sections of which one is stained for SDH activity the other for "reversed"-ATPase activity.     

Energization of sulfate transport in yeast

Sulfate uptake by Saccharomyces cerevisiae is stimulated about 12-fold by preincubation of cells with 1% d-glucose or 1% ethanol. The $\text{K}{}_{\mathrm{<mtext>T</mtext>}}$ remains unchanged (0.34–0.38 mM), the $\text{J}{}_{\mathrm{<mtext>mar</mtext>}}$ increase from 18–20 to 195–230 and 170–185 nmol/min per g dry wt., respectively, after glucose and ethanol preincubation. The stimulation involves protein synthesis (it is suppressed by cycloheximide), has a half-time of 18 min and requires mitochondrial respiration (no or low effect in respiration-deficient mutants and those lacking ADP-ATP transport in mitochondria, as well as after anaerobic preincubation of the wild-type strain, and in low-phosphate cells). The presence of NH₄⁺ and some amino acids (e.g., leucine, aspartate, cysteine and methionine) depressed the stimulation while that of cationic amino acids (typically arginine and lysine) and of K⁺ increased it by 50–80%. The stimulated (i.e., newly synthesized) transport system was degraded with a half-life of about 10 min.     

Inhibition of peristaltic activity in the guinea-pig ileum by specific stress stimulus; its reversal by naloxone and indomethacin

During continuous peristaltic reflex activity of the isolated guinea-pig ileum a model stress stimulus, elevated intraluminal pressure (120 mm H₂O) plus increased longitudinal tension (3 g) was applied for 2 min. The resulting inhibition of peristalsis outlasted the initial stimulus by several min. The inhibitory interval was shortened or abolished in the presence of naloxone (0.5 μM), an opiate receptor antagonist, or in the preparations made acutely tolerant to morphine. This seems to suggest an involvement of endorphins. An inhibition of endogenous prostaglandin synthesis by indomethacin (5 μM) decreased the amplitude of peristaltic longitudinal muscle contractions, and these contractions were increased in response to the stress stimulus in the presence of naloxone. Thus the response of the guinea-pig ileum to stress stimulation could be profoundly modified by an interference with endorphin and prostaglandin systems.     

Pulsed-Field Gel Electrophoresis Analysis of Vibrio vulnificus Strains Isolated from Taiwan and the United States

Vibrio vulnificus is a marine bacterium that causes human wound infections and septicemia with a high mortality rate. V. vulnificus strains from different clinical and environmental sources or geographic regions have been successfully characterized by ribotyping and several other methods. Pulsed-field gel electrophoresis (PFGE) is a highly discriminative method, but previous studies suggested that it was not suitable for examining the correlation of V. vulnificus strains from different origins. We employed PFGE to determine its efficacy for characterizing V. vulnificus strains from different geographic regions, characterizing a total of 153 strains from clinical and environmental origins from the United States and Taiwan after SfiI or NotI digestion. V. vulnificus strains showed a high intraspecific diversity by PFGE after SfiI or NotI digestion, and about 12% of the strains could not be typed by the use of either of these enzymes. For PFGE with SfiI digestion, most of the clinical and environmental strains from the United States were grouped into cluster A, while the strains from Taiwan were grouped into other clusters. Clinical strains from the United States showed a higher level of genetic homogeneity than clinical strains from Taiwan, and environmental strains from both regions showed a similarly high level of heterogeneity. PFGE with NotI digestion was useful for studying the correlation of clinical strains from the United States and Taiwan, but it was not suitable for analyzing environmental strains. The results showed that PFGE with SfiI digestion may be used to characterize V. vulnificus strains from distant geographic regions, with NotI being a recommended alternative enzyme.     

R factors ofEscherichia coli strains causing urinary tract infections,their types of transfer factors and differences in their transmissibility toCitrobacter andSalmonella typhimurium recipient strains

A total of 107 R factors was demonstrated in 103Escherichia coli strains isolated from the urine of patients with urinary tract infections. Four of the strains were in a hetero-R state, i.e. each cell possessed two R factors with different types of transfer factors. Of the total number of R factors, 76.6% were fi⁺ and 23.4% fi⁻. The recipient strainCitrobacter O-7, 3b, 1c accepted all the given R factors, while the other,Salmonella typhimurium, accepted only 20%. Both the recipient strains accepted fi⁺ and fi⁻ factors. We presume that the transmissibility of R factors depends on their type of transfer factor, but in relation to criteria other than fi⁺ and fi⁻ and the recipient's affinity.     

Sulfhydryl analogues of adenosine diphosphate: chemical synthesis and activity as platelet-aggregating agents.

2-Thioadenosine 5'-diphosphate (2-SH ADP), 2,2'-dithiobisadenosine 5'-diphosphate (2,2'-(S-ADP)2), 8-thioadenosine 5' diphosphate (8-SH ADP), and 6-mercaptopurine riboside 5'-disphosphate (6-MPRDP) were synthesized as potential affinity labels for ADP receptors on the blood-platelet membrane. The mean relative activities of these compounds in aggregating human platelets suspended in homologous plasma were 155% (2,2'-(S-ADP)2), 74% (2-SH ADP), 0.65% (8-SH ADP), and 0.08% (6-MPRDP). The mean relative activities against washed platelets were 249% (2,2"-(S-ADP)2) and 115% (2-SH ADP), whereas no aggregation occurred with 8-SH ADP or 6-MPRDP. The last two compounds were found to be weak inhibitors of ADP-induced aggregation. Therefore, thio-substitution at postition 2 followed by oxidation to a disulfide appears to be the most promising approach to further studies of affinity labelling of membrane ADP-receptors.     

Influence of NaCl,KCl and MgSO4 concentration on total and irreversible adsorption of T2r phage on isolated cell walls

The dependence on salt concentration of steady-state total and irreversible adsorption of T2r phage on isolated bacterial cell walls was studied. Solutions of NaCl, KCl and MgSO₄ of different molarity were used and a difference between the total and the irreversible adsorption at lower concentration of NaCl and KCl, but not in MgSO₄ solutions, was found. The effect of KCl on total adsorption was similar to that of MgSO₄ in which case the adsorption begins at lower molar concentrations than with NaCl.