Experimental transmission of Bartonella henselae by the cat flea.

Bartonella henselae is an emerging bacterial pathogen, causing cat scratch disease and bacillary angiomatosis. Cats bacteremic with B. henselae constitute a large reservoir from which humans become infected. Prevention of human infection depends on elucidation of the natural history and means of feline infection. We studied 47 cattery cats in a private home for 12 months to determine the longitudinal prevalence of B. henselae bacteremia, the prevalence of B. henselae in the fleas infesting these cats, and whether B. henselae is transmitted experimentally to cats via fleas. Vector-mediated transmission of B.henselae isolates was evaluated by removing fleas from the naturally bacteremic, flea-infested cattery cats and transferring these fleas to specific-pathogen-free (SPF) kittens housed in a controlled, arthropod-free University Animal Facility. B. henselae bacteremia was detected in 89% of the 47 naturally infected cattery cats. A total of 132 fleas were removed from cats whose blood was simultaneously cultured during different seasons and were tested individually for the presence of B. henselae DNA by PCR. B. henselae DNA was detected in 34% of 132 fleas, with seasonal variation, but without an association between the presence or the level of bacteremia in the corresponding cat. Cat fleas removed from bacteremic cattery cats transmitted B. henselae to five SPF kittens in two separate experiments; however, control SPF kittens housed with highly bacteremic kittens in the absence of fleas did not become infected. These data demonstrate that the cat flea readily transmits B. henselae to cats. Control of feline infestation with this arthropod vector may provide an important strategy for the prevention of infection of both humans and cats.     

Einsparung von Diclofenac durch B-Vitamine: Ergebnisse einer randomisierten Doppelblindprüfung mit reduzierten Tagesdosierungen von Diclofenac (75 mg Diclofenac versus 75 mg Diclofenac plus B-Vitamine) bei akuten Lendenwirbelsäulensyndromen

Summary Pain syndromes of the lumbar spine are one of the main problems in orthopedic practice. The therapeutic effect of NSAIDs is not subject to doubt in this connection.But considering that the application of NSAIDs is frequently associated with side effects, a reduction of dosage would be to the patient's benefit. Clinical studies have shown that concomitant treatment with vitamins B₁, B₆, B₁₂ and diclofenac leads to a more efficient pain relief than treatment using diclofenac alone and thus provides the possibility of saving NSAIDs.This clinical trial was carried out in order to determine whether these results can also be achieved when a reduced dosage of diclofenac (75 mg daily) is used.123 patients with acute pain syndromes of the lumbar spine were treated with either B-vitamins and diclofenac or diclofenac alone for a maximum of 7 days. There was the option to terminate therapy in the trial after 3–4 days in the case of total pain relief.45 patients could stop the treatment due to remission of symptoms. 30 patients belonged to the combination therapy group, the other 15 took diclofenac alone; this difference is statistically significant (p< 0.05).All parameters concerning pain relief and movement of the vertebral column showed statistically significant differences in favour of the B-vitamin-diclofenac-combination, too.The results document the positive influence of B-vitamins on painful vertebral syndromes and indicate that B-vitamins contribute to saving of NSAIDs by shortening the treatment time and reducing daily NSAID-dosage.

     

Production of hemolysin and other extracellular enzymes by clinical isolates of Pseudomonas pseudomallei.

One hundred clinical isolates of Pseudomonas pseudomallei from humans were tested for their ability to produce extracellular, biologically active substances which are thought to contribute to the virulence of Pseudomonas species. All isolates produced at least on extracellular enzyme; 91 strains were positive for lecithinase, lipase, and protease; but none was positive for elastase. Ninety-three strains produced a hemolysin which was detectable around the heavy growth on saline-washed sheep erythrocyte brain heart infusion agar but not demonstrable around individual colonies or in broth culture filtrate. In contrast, a hemolysin which was cytolytic around individual colonies of P. pseudomallei on the assay plate and in broth culture filtrate was exhibited by four strains. By using one of these four isolates as the test strain, the latter hemolysin was characterized further. It was heat labile, most active in an acid environment (pH 5.5), and cytolytic in broth culture filtrate for a variety of animal and human erythrocytes. Sterols, particularly cholesterol and 7-dehydrocholesterol, inhibited its hemolytic activity, but the activity was not enhanced by reducing agents or suppressed by reagents which modify sulfhydryl-activated hemolysins. A nonhemolytic mutant of the test strain of P. pseudomallei retained the extracellular enzymes of its parent, indicating that the hemolysin was not a lecithinase, lipase, or protease.     

Flow cytometry: Potential utility in monitoring drug effects in breast cancer

Summary Flow cytometric analysis of DNA ploidy and S-phase fraction are well recognized prognostic indicators in breast cancer. The present paper deals with the widening of the applications of flow cytometry to monitoring the effectiveness of antiestrogen therapy, detecting clonal selection and emergence of drug resistance, and monitoring chemosensitizing properties of drugs. Antiestrogen activity can be studied by DNA flow cytometry to address clinical research problems such as patient-specific pharmacokinetics, dosing compliance, and acquired antiestrogen resistance. Patient plasma specimens containing various concentrations of triphenylethylenes can be monitored for drug-induced effects using cell cycle measurements and correlated toin vivo drug levels. DNA flow cytometry has also been instrumental in the study of the effects of prolonged low-dose (0.5 µM for > 100 days) tamoxifen treatment on human estrogen receptor negative MDA-MB-231 cells, where it was shown that tamoxifen may significantly alter cell cycle kinetics and tumorigenicity of these cells, selecting a new, more aggressive, and rapidly growing clone. Lastly, it has been shown that the chemosensitizing properties of another triphenylethylene antiestrogen, toremifene, on estrogen receptor negative, multidrug resistant MDA-MB-231-A1 human breast cancer cells can be studied using flow cytometric analysis. Toremifene (and its metabolites N-desmethyltoremifene and toremifene IV) are able to resensitize MDA-MB-231-A1 cells to vinblastine and doxorubicin, as reflected in a marked shift of cells to G₂/M phase of the cell cycle. Flow cytometry is a widely available technique that might be applied clinically to monitor, at the cellular level, drug effects on tumors, including the modulators of drug resistance.     

Kraepelin-oriented research-diagnosable schizophrenia,mania, and depression in schneider-negative schizophrenics

Summary The rigorous neo-Kraepelinean research criteria of the St. Louis/ Iowa and Taylor groups were applied to case record data of 116 first admissions of Schneider-negative schizophrenics—that is, those without first-rank symptoms (FRSs)—hospitalized in a strongly Schneider-oriented German University Psychiatric Clinic from 1962 to 1971. This sample had a total of 45.7% (53 cases) of psychiatric illness diagnosable by research methods. Indeed, only 31% (36 cases) of Schneider-negative schizophrenics turned out to have research-positive Kraepelin-oriented schizophrenia; and of these, 21 fulfilled both sets of research criteria for schizophrenia. It is important that 14.6% (17 cases) of Schneider-negative schizophrenia consisted of research-diagnosable affective disorder, with mania making up 5.2% and depression 9.4% of this figure. The findings suggest that a sample of Schneider-oriented schizophrenia without FRSs as routinely diagnosed in Germany does not seem to represent a clear-cut homogeneous and uncontaminated group of schizophrenics.