In vitro activity of ampicillin plus sulbactam against anaerobes compared to ampicillin and cefoxitin

The antimicrobial susceptibility of 195 recent clinical isolates of anaerobic bacteria was studied to ampicillin alone, ampicillin + 1 mg/l sulbactam, ampicillin + 5 mg/l sulbactam, and cefoxitin by means of agar dilution tests. The ampicillin-sulbactam combinations were the most effective drugs against species of the Bacteroides fragilis group, the MIC90 of ampicillin + 5 mg/l sulbactam for B. fragilis being less than 1 mg/l, compared to 256 mg/l of ampicillin, 4 mg/l of ampicillin + 1 mg/l sulbactam, and 8 mg/l of cefoxitin. No significant difference between ampicillin alone and in combination with sulbactam was observed against gram-positive anaerobic rods, Peptococcus spp. and Peptostreptococcus spp. with MIC's less than 2 mg/l.

Quantitative studies on the vaginal flora of asymptomatic women and patients with vaginitis and vaginosis

Vaginal washings of 22 patients with vaginitis, 11 with vaginosis, and 12 healthy subjects were investigated quantitatively and qualitatively for aerobic and anaerobic bacteria and yeasts. Gardnerella vaginalis was recovered from 9 of the vaginitis patients, 7 of the vaginosis patients, and 4 of the asymptomatic subjects. Obligate anaerobes were found in 11 of the vaginitis patients, 4 of the vaginosis patients, and none of the control subjects. Bacteroides bivius was the anaerobe most frequently isolated from symptomatic subjects. Anaerobic vibrios were recovered twice from symptomatic subjects. The counts for Gardnerella vaginalis and anaerobes when present were generally very high. The most frequent aerobes were beta-hemolytic streptococci (group B) and staphylococci.

The formation of a neo-intima in textile prostheses implanted in the aorta of rats and dogs

The formation of a neo-intima in textile prostheses implanted in the rat and dog aorta was studied by means of light- and scanning electron microscopy. Two independent cellular layers (the superficial and deep ingrowth layers) developed on the free surface and under the fibrin layer initially deposited on the inner surface of the prostheses. The superficial ingrowth layer invades the prosthesis from both the proximal and distal aortic stumps and extends over the primary fibrin layer, or replaces it. This layer consists mainly of smooth muscle cells of the triangular aortic type covered by endothelial-like cells. The deep ingrowth layer originates from cellular elements of the prosthetic bed. Fibroblasts, myofibroblasts and spindle-shaped smooth muscle cells invade the fibrin layer through the interstices of the fabric structure of the prosthesis. Precursors of endothelial cells, however, are absent from this population. The superficial and the deep ingrowth layers may become joined by progressive replacement of the fibrin layer, but remain distinguishable because of their different cellular components. When a continuous cellular layer is established on the inner surface of the prosthesis, and this is then covered by endothelial-like cells, the neo-intima formed remains stable during long-term studies.

Influence of adrenergic agonists and antagonists on lymphokine secretion in vitro

Spleen cells of mice and lymph node lymphocytes of rats were cultured with epinephrine, norepinephrine and alpha- and beta-adrenergic drugs to determine effects on lymphokine secretion. After an incubation of 4.5 h it was found that the naturally occurring catecholamines and adrenergic drugs (isoprenaline, orciprenaline, terbutaline, norfenephrine, phenylephrine, clonidine, dobutamine) could induce the secretion of charge-changing lymphokines and lymphokines that stimulate the migration of lymphocytes. The beta-blocker propranolol inhibited the lymphokine secretion evoked by epinephrine and by beta-adrenergic agonists, whereas the alpha-blocker phentolamine antagonized the effects elicited by alpha-adrenergic drugs. Phenylethylamine also induced a significant secretion of lymphokines. Two non-phenylethylamines had no effect. The stimulatory capacity of adrenergic agonists, the inhibitory activity of the appropriate antagonists and the comparison with two non-phenylethylamines support the hypothesis on specific influence of catecholamines on the lymphocyte function.

Localization of growth hormone-releasing hormone in the human hypothalamus and pituitary stalk

The localization of the recently identified GH-releasing hormone (GHRH) in the human hypothalamus and pituitary stalk was determined by microdissection techniques and a specific RIA for GHRH. The highest concentrations of GHRH immunoreactivity (IR-GHRH) in the hypothalamus were found in the area of the infundibular nucleus (83 +/- 4 ng/mg protein; average +/- range). Lower quantities were found in other hypothalamic regions. Very high concentrations of IR-GHRH were present in the upper portion of the pituitary stalk (1454 +/- 48 ng/mg protein), and they decreased gradually toward the distal end of the stalk (21 +/- 3 ng/mg). This concentration gradient suggests that the peptide reaches the anterior pituitary mainly by way of the long portal vessels. Somatostatin, the second neuropeptide involved in the regulation of GH secretion from the anterior pituitary, had a pattern of distribution along the pituitary stalk very similar to that of IR-GHRH.

Growth hormone releasing factor-like immunoreactivity in human milk

The presence of immunoreactive growth hormone-releasing factor (GRF) in human milk has been demonstrated. By using sequential high performance liquid chromatography, it has been shown that most of the immunoreactivity co-elutes with the synthetic, hypothalamic-like, GRF (1-40). The concentrations of GRF detected (between 152 and 432 pg GRF/ml milk) exceed several fold its values in plasma.

Immunomodulation by some oligopeptides

The influence of bradykinin, some of its analogues, substance P and different partial sequences on lymphoid cells was studied under in vitro conditions. The oligopeptides bradykinin and substance P were found to be able to induce the secretion of charge-changing and chemokinetic lymphokines in very low concentrations. In each case, bell-shaped dose-response curves were registered in a concentration range from 10(-12) to 10(-6) M. An analysis of the lymphokine patterns suggests that T cells are the producer cells of charge-changing lymphokines. Comparing the structure-activity relationships of the peptides, the amino acid sequence Arg-Pro at the N-terminal region of bradykinin and substance P or Pro-Arg at the C-terminal part of tuftsin and rigin appear to be responsible for the lymphokine secretion.

Effects of muramyl dipeptide and trehalose dimycolate on resistance of mice to Toxoplasma gondii and Acanthamoeba culbertsoni infections

The effects of synthetic muramyl dipeptide (MDP) and natural trehalose dimycolate (TDM) against parasitic infections by intracellular Toxoplasma gondii and free-living Acanthamoeba culbertsoni were studied. Significant resistance against oral T. gondii infection was induced by intraperitoneal pretreatment with TDM but not with MDP. The protective effect of TDM against T. gondii was corroborated by a significant reduction in the number of cysts in brains of pretreated animals and elevated serum antibody levels. Partial protection against lethal intranasal A. culbertsoni infection was conferred by specific immunization with viable trophozoites of nonpathogenic Acanthamoeba lugdunensis. The nonspecific resistance induced by intravenous pretreatment with MDP was similar to, whereas that stimulated by TDM was lesser than the protection conferred by A. lugdunensis. The Fc receptor-mediated phagocytosis of 51Cr-labeled sheep red blood cells by alveolar macrophages was enhanced by MDP. The phagocytic activity of peritoneal macrophages was increased by lower doses of TDM.