Comparative Characterization and Biotyping of Staphylococcus aureus Isolates from Human and Bovine Sources

One Hundred and ten alpha and/or delta-haemolytic isolates (collection 1), 50 beta haemolytic isolates (collection 2) from bovine mastitis, and 100 previously phage-typed alpha- and delta-haemolytic isolates (human collection) og Staphylococcus aureus (S. aureus) were tested and biotyped according to the scheme of Hajek & Marsalek (1971). Among collection 1 isolates, 85 (77.3 %) belonged to the human biotype A (human source). Twenty two (20 %) designated as non-allotted strains, possessed characteristics of both animal and human sources. The remaining 3 isolates (2.7 %) in this collection belonged to biotype C (animal source). All collection 2 isolates which were used as control strains for animal sources, belonged to biotype C. The human collection that contained 100 phage-typed haemolytic isolates (representing all human phage groups) were used as a control for the human source. Irrespective of their phage group, these strains predominantly produced alpha and/or delta haemolysins and belonged to the human biotype A. This study also recommended the use of a combined plasma crystal violet agar medium for the presumptive identification of S. aureus biotypes.     

Transplantation of fetal growth hormone-releasing factor-immunoreactive neurons into the ventricular system of adult MSG-treated rats.

Fetal (17-18 days of gestation) mediobasal hypothalamic tissue (MBH) was transplanted into the third ventricle of adult, male rats which had been treated neonatally with monosodium glutamate (MSG). MSG treatment caused a marked reduction of growth hormone-releasing factor-like-immunoreactive (GRF-i) perikarya in the arcuate nucleus and GRF-i fibers in the median eminence (ME), as compared to littermate controls. When normal fetal MBH was transplanted into the third ventricle of MSG recipients, numerous GRF-i perikarya were located within the graft four weeks following surgery. GRF-i fibers in the ME of MSG-treated rats were enhanced when MBH grafts were in close contact with the ME, but not when transplants were located dorsally or rostrally in the third ventricle without making contact with the recipient's ME. Fetal cerebral cortex, which was grafted as a control tissue, did not contain GRF-i neurons. These immunohistochemical results suggest that grafted fetal GRF-i perikarya may contact the recipient's ME to increase the content of GRF previously depleted by exposure to MSG.     

Human ecology: A unifying science?

A historical review of human ecology as it developed in geography, anthropology, sociology, and psychology indicates that this science's ambiguity has been perpetuated by the reluctance of academicians in specialized disciplines to work collaboratively. While human ecology is considered a unifying science, few attempts have been made to reconcile differences among disciplinary self-interests, thereby preventing interdisciplinary approaches to contemporary man-environment problem solving. Human ecology will remain a debatable, ambiguous, and fragmented science unless present barriers to cooperative effort are overcome and the various disciplines unite in seeking solutions to current societal problems.     

Influences of clotting factors (thrombin, factor XIII) and of fibronectin on the growth of tumor cells and leukemic cells in vitro

Thrombin, factor XIII and fibronectin were incubated with cultures of mouse sarcoma cells, human cervix carcinoma cells (HeLa cells) and cells of an acute lymphoblastic leukemia. Thrombin induced a significant increase of 3H-thymidine uptake into cells with a 1,5- to 2-fold increase of cell count. The cells of an acute lymphoblastic leukemia showed a similar response to the influence of thrombin. Factor XIII in tumor cells merely induced an increase of 3H-thymidine uptake, the cell count remained constant. The cells of an acute lymphoblastic leukemia showed under the influence of factor XIII a significant increase of cell count and thymidine uptake. HeLa cell growth was optimal at low fibronectin concentrations. Fibronectin concentrations of 1 mg/ml to 3 mg/ml inhibited HeLa and mouse sarcoma cell growth.