Biomedical subjects
Publications and source records attributed to H Baer.
Thirteen cases of polymicrobial bacteremia occurring in obstetric patients are reported. The most commonly occurring combination involved the Bacteriodeaceae, anaerobic streptococci, and Hemophilus vaginalis. In 3 cases the spectrum of bacterial isolates obtained from the intravascular compartment changed significantly.
Inbred strain 2 and random-bred guinea pigs injected oxazolone in incomplete or complete Freund's adjuvant showed contact reactions within an hour after topical application when tested 3 weeks post-sensititization. The application when tested 3 weeks post-sensitization. The time for appearance of skin reactions at 5 days post-sensitization was 8 to 24 hr, more along classic delayed-type hypersensitivity lines. Immune serum harvested several weeks after sensititazation was effective for passive transfer of early skin reactivity, while serum at 5 to 10 days was not. Lymph node cells taken 5 days after sensitization of donors could transfer only the late skin reactivity to histocompatible recipients; lymph nodes taken at 15 days did not contain cells capable of such transfers. The heterogeneity of mechanisms involved in the production of contact dermatitis suggested by these results provides new approaches to studies in this area of allergy research.
The use of honeybee venoms and their components may assist in the elucidation of the pathophysiology of reactions to honeybee stings. This initial study compared venoms from various sources by chemical and biological assays, and significant variations were observed. Ten different bee venoms were compared by nitrogen analysis, mouse toxicity, hyaluronidase content, and antigenicity. Based on mouse toxicity, hyaluronidase content, and gel diffusion analysis, two groups of bee venoms could be differentiated. Venoms in one group, Group A, were more toxic, contained hyaluronidase, and showed an additional precipitin band. All venoms contained mellitin as a major fraction, which formed nonimmune precipitin bands during gel diffusion analysis. Gel filtration chromatography and dialysis separated the venoms into components that were then identified by enzyme assays, rat mast cell degranulation, hemolytic activity, and gel diffusion analysis. The venoms within Group A showed similar components, some of which, most noticeably hyaluronidase, were not present in Group B. Dialysis showed that a large portion of the venom could pass through a cellophane membrane including a portion of the phospholipase A. Heterogeneous molecular weights were found for phospholipase A by both gel filtration and dialysis, and may reflect variation in carbohydrate content. It appears that bee venom variability for whatever reason, a heterogeneous MW antigen, and a non-immune precipitable component require careful consideration in any study involving this venomm. These studies have yielded relatively pure, identified bee venom components which can be employed in further studies investigating reactions to honeybee stings.
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Gram-negative organisms, responsible for a high rate of colonization and infection in an intensive care nursery, were recovered frequently from hands of personnel, despite regular hand antisepsis. In sequential hand cultures contamination of hands by gram-negative organisms was transient in some nurses, but active multiplication of the organisms occurred on the hands of others and in a few nurses a temporary carrier state appeared to exist. The results of this study suggest that the hands of hospital personnel may serve not only as a passive vehicle in the nosocomial transmission of gran-negative bacteria, but also may constitute a reservoir of nosocomial organisms.
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The O-1 bacteriophage test of Cherry et al. (1954) for the presumptive identification of salmonellae in the diagnostic laboratory was investigated. A phage lysate with a titer of 10(12) plaque-forming units per ml was found to be optimal. This preparation lysed 98.2% of Salmonella strains tested, while maintaining its high specificity for salmonellae. Gram-negative organisms other than salmonellae were resistant to the O-1 phage; however, 5.9% of Escherichia coli strains tested were susceptible. The O-1 phage test is a simple, rapid, inexpensive, sensitive, and specific procedure for the identification of salmonellae in the diagnostic laboratory. A presumptive identification is obtained 1 day earlier than with conventional biochemical tests.
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