Staphylococcus aureus isolates from five large teaching hospitals and one medium-size community hospital located in geographically distant parts of Brazil, in the south and southeast (Rio de Janeiro, Niteroi, Sao Paulo, Porto Alegre) and in the north (Manaus), were tested for their antibiotic resistance patterns and genetic backgrounds. Eighty-five of the 152 isolates were identified as methicillin-resistant S. aureus (MRSA) by using a combination of an agar dilution screen and a mecA gene-specific DNA probe. All MRSA isolates were resistant to penicillin, erythromycin, gentamicin, oxacillin, and cephalothin, and the majority of isolates (74%) were also resistant to chloramphenicol, sulfamethoxazole-trimethoprim, ciprofloxacin, and clindamycin as well and were susceptible only to vancomycin. Isolates obtained from hospitals in Sao Paulo, Rio de Janeiro, Niteroi, and Porto Alegre (1,600 km from one another) and Manaus (3,700 km from Rio de Janeiro) were examined by a variety of molecular fingerprinting techniques: the nature of the mecA polymorph and Tn554 attachment sites and restriction fragment length polymorphism of genomic DNAs after SmaI restriction and separation of the digested DNA by pulsed-field gel electrophoresis. The overwhelming majority of the isolates shared a common pulsed-field gel electrophoresis pattern and carried mecA polymorph III in combination with Tn554 pattern B, indicating the presence of a single, epidemic MRSA clone spread over large geographic distances of Brazil.

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Electron microscopy of bacterized and axenic trophozoites of Entamoeba histolytica showed only slight differences in ultrastructure between the two . As with other species of Entamoeba so far studied, this species lacks typical mitochondrial structures and formed endoplasmic reticulum . Dense clusters of glycogen particles are especially characteristic in axenic amebas . Microtubular structures 360 A in diameter appear randomly oriented in both bacterized and axenic trophozoites . Ribonucleoprotein (RNP) bodies are of two typical formselongate, parallel arrays of helices (the classical chromatoid bodies), and short helical fragments . Both kinds of helix show a recurring pitch angle of 68-80°and an over-all diameter of 480 A . RNP particles comprising the helices average 180 A in diameter . The longitudinal axes of adjacent helices are 440 A apart . Following RNase digestion of water-soluble methacrylate sections, helices show a core approximately 60 A in diameter. Short helices are also associated with digestive vacuoles . Free RNP particles per se are never seen within digestive vacuoles, but intact short helices are frequently detected closely associated with the external membrane of digestive vacuoles . In some cases, continuation of externally intact helical forms could be related to filamentous material within the vacuole . Acid phosphomonoesterase activity could be demonstrated within digestive vacuoles where deposition of reaction product is especially intense on the filamentous material .

It has been established that, in those species studied, intraluminar digestion does not occur in triclad flatworms (Willier, Hyman and Rifenburgh, 1925;Jennings, 1957), but that digestion takes place within food vacuoles in the phagocytic cells of the gastrodermis. A number of investigators have observed the disintegration of ingested food particles within these cells (Arnold, 1909;Saint-Hilaire, 1910;Jacek, 1917;von Levitzow, 1943), but the methods they employed did not permit elucidation of the mechanisms involved except in a most general way. Kelley (1931), studying the intracelular digestion of nucleoprotein in D. dorotocephala by means of the Feulgen reaction with and without acid hydrolysis, showed that the ingested material was hydrolyzed within the first two hours.To our knowledge, no previous study has characterized the hydrolytic enzymes in the phagocytes of planarians. The present report considers the relationship of three such enzymes to current concepts of intracellular digestion. Materials and MethodsSpecimens of Dugesia dorotocephala and D. tigrina were used for this study. The animals were maintained as stock cultures at 18° C. and fed routinely once every ten days on minced rat or mouse liver. Experimental animals were isolated in fingerbowls and starved for at least three weeks. Some of these were fed raw rat or mouse liver, and others boiled liver to determine if enzyme activities in raw food were transferred to the gut. No differences in enzyme activities between animals fed raw or boiled liver were demonstrable by the staining methods employed. The worms were observed during feeding ; post-feeding times were determined from the moment the animals ceased feeding.For the demonstration of those enzyme activities surviving chemical fixation, specimens were initially fixed in warm (37° C.) Baker's calcium-formalin for 5 minutes to prevent discharge of the gut contents. They were then placed in calcium-formalin at 4° C. for 24 hours, washed for 5 minutes in distilled water and cut on a CCX-freezing microtome at 8-10/*. Material thus prepared was incubated for acid phosphatase activity by a slight modification of the method of Gomori (1952). Sections were incubated for 15-30 minutes in a 0.1 M 2glycerophosphate and lead nitrate mixture buffered to pH 5.0 with 0.05 M acetate buffer.Aminopeptidase activity was visualized by the method of Burstone and Folk (1956). Animals were placed on Monel grids and frozen in isopentane chilled by liquid nitrogen to -160° C. After quenching, the worms were dehydrated for 24 118, 315-323.

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Fourteen female Myotis lucifugus from a summer colony were adapted to laboratory conditions for periods up to 60 days. Animals were then divided and exposed to the following conditions: ( I ) active bats exposed to normal summer laboratory temperature and humidity; (11) active bats exposed to normal summer laboratory temperature but low humidity; (111) cold-stored bats; (IV) cold-stored bats exposed to low humidity. All cold-stored bats entered a state of apparent deep hibernation, carrying out characteristic reflexes upon being awakened. Their thyroid glands showed significant loss of secretory activity, Staining for ATPase activity (method of Wachstein and Meisel) on formalinfixed sections of kidney showed that there was increased infolding as well as increased enzymic activity of the plasma membranes of the proximal convolutions from all cold-stored bats. Proximal convolutions from kidneys of active bats showed decreases in the degree of invagination of the plasma membranes with apparently expanding basal lamellae. Acid phosphatase activity (Gomori) was confined to "phagosomes" in the proximal convolutions of active bats; cold-stored bats showed no activity. Staining with the periodic Schiff method showed irregular staining of the brush border of tubules from active bats; cold-stored animals showed a regular brush border with this method. The results suggest that the histochemical methods employed reveal differences in kidney function between the active and cold stored animals.An apparent decrease in plasma volume has been described for hibernating mammals such as the little brown bat, Myotis lucifugus (Kallen, '60), and the thirteenlined ground squirrel (Hong, '58). Such a shift in water also reflects a state of relative dehydration on the part of animals in undisturbed hibernation when compared with animals which are active and have ready access to water. Hong ('58) presented evidence that decreased plasma volume filtered by the kidney accompanies a decrease in renal blood flow during hibernation but additional quantitative information on body fluids during hibernation appears to be lacking (Riedesel, '60).The functional adaption of the kidney to hemodynamic alterations in the hibernating animal could be reflected in morphological alterations or adaptations within the nephron. To date, however, no investigations have been undertaken to investigate this possibility. The purpose of this study was to visualize structural and functional changes accompanying the shifts in water described by the above physiological investigations using specific histochemical methods. For this, we employed kidneys from active and artificially coldstored bats (Myotis Zucifugus) including some animals exposed to decreased humidity. MATERIALS AND METHODSFourteen female Myotis lucifugus from a laboratory stock colony captured near Ringwood, New Jersey during July, '62, were employed for this study. For initial adaptation to laboratory conditions, all animals were maintained in a semi-darkened cage for 60 days. They were fed ad ...

The effects of dexamethasone on prostaglandin secretion by cultivated rabbit coronary microvascular endothelial (RCME) cells were investigated. Incubation of RCME cells with dexamethasone resulted in a time- and concentration-dependent decrease in prostaglandin accumulation in the culture media and reduced basal and A23187-stimulated prostaglandin (PG) E2 and 6-keto-PGF1 alpha release. The maximal effects of dexamethasone (50-80% inhibition) were achieved after 16-18 h of incubation with the steroid at a final concentration of 10(-7) M. The effects of dexamethasone treatment were partially reversed 24 h after removal of the steroid from the culture media. Dexamethasone treatment did not reduce arachidonic acid-stimulated prostaglandin synthesis, indicating that the level of inhibition was proximal to that of cyclooxygenase. The inhibitory effects of dexamethasone could be prevented by pretreatment of the RCME cells with actinomycin D or cycloheximide, suggesting a requirement for protein synthesis in the inhibitory action of dexamethasone. Conditioned media from dexamethasone-treated cells contained a factor that inhibited porcine pancreatic phospholipase A2 (PLA2) in vitro. Transfer of conditioned media from dexamethasone-treated cells to untreated cells did not reduce basal or stimulated prostaglandin release; in contrast, a stimulatory action was consistently observed. Adherence of rabbit peripheral polymorphonuclear leukocytes (PMN) to RCME cells was reduced when the leukocytes were pretreated with 10(-7) M dexamethasone (4 h). However, dexamethasone pretreatment of the RCME cells did not significantly effect granulocyte adhesion. Thus coronary microvascular endothelial cell prostaglandin production is regulated by glucocorticoids, and glucocorticoid-pretreated microvascular endothelial cell release an inhibitor of PLA2 activity into the culture media.(ABSTRACT TRUNCATED AT 250 WORDS)