Enteric Pathogens in Monkeys

From 1964 to 1967, 6,646 monkeys, representing 10 primate species, were examined for Shigella and Salmonella infections upon arrival at the National Center for Primate Biology. Of these animals, 12% were infected with Shigella, and 75% of the Shigella isolates were S. flexneri 4. The incidence of Salmonella infections decreased from 12 to 3% during the period of study. Epidemiological studies of animals in the colony for 90 days or more indicated no seasonal variation in the occurrence of Shigella and Salmonella. Many of the isolates from incoming monkeys as well as from laboratory-conditioned animals were resistant to chloramphenicol, dihydrostreptomycin, and tetracycline. The possible operation of drug-resistance factors in these infections is discussed.     

Survival of Aerobic and Anaerobic Bacteria in Chicken Meat During Freeze-Dehydration, Rehydration, and Storage

Total and anaerobic counts were ascertained on boneless, cooked, cubed, frozen chicken meat. We determined survival of aerobes and anaerobes in the natural flora after the meat was freeze-dehydrated and rehydrated at room temperature for 30 min and at 50, 85, and 100 C for 10 min. Total and anaerobic counts of bacteria in the rehydrated meat were established during storage of samples at 4, 22, and 37 C-until a spoilage odor was detected. Samples were also inoculated with Clostridium sporogenes and were dried and rehydrated at 100 C and stored at 37 C. Approximately 21% of the aerobes and 37% of the anaerobes survived drying and rehydration at room temperature. Many genera of aerobes, anaerobes, and facultative anaerobes survived drying and rehydration at 50 C; only sporeformers survived rehydration at 85 or 100 C. Low-temperature (4 C) storage of rehydrated meat produced ample shelf life (over 20 days), whereas storage at the higher temperature resulted in a shelf life of less than 30 hr. Approximately 81% of the C. sporogenes cells survived rehydration at 100 C and grew to over 10(7) cells within 40 hr. Our study presents additional data for adequate microbiological control in processing of freeze-dehydrated meat. Also, it points out the natural selection for sporeformers at high temperature of rehydration, stressing the need for consumer education in product handling for safety purposes.     

Allescheria boydii and Aspergillus fumigatus Skin Test Antigens

May, Lewis K. (Woman's Medical College of Pennsylvania, Philadelphia), Ralph A. Knight, and H. William Harris. Allescheria boydii and Aspergillus fumigatus skin test antigens. J. Bacteriol. 91:2155-2157. 1966.-Protein and polysaccharide fractions were extracted from culture filtrates of Allescheria boydii and Aspergillus fumigatus by the methods of Seibert and of Heidelberger, and injected intradermally into guinea pigs previously infected with these fungi. The diameter of erythema and induration was determined at 8, 24, and 48 hr. The protein and polysaccharide antigens yielded specific skin reactions in homologously infected guinea pigs. Erythema appeared at 8 hr with both the protein and polysaccharide antigens. At this time, the polysaccharide skin tests showed erythema and a central blanched wheal. A similar wheal was not observed with the protein. The erythema of the polysaccharide reaction began fading at 24 hr, whereas the protein reaction remained unchanged through 48 hr with both antigens. In guinea pigs, the area of erythema was more constant and thus easier to measure than was induration.     

Inhibition of hexose transport in the human erythrocyte by 5, 5′-dithiobis(2-nitrobenzoic acid): Role of an exofacial carrier sulfhydryl group

Summary The sulfhydryl reagent 5, 5-dithiobis (2-nitrobenzoic acid) (DTNB) was used to study the functional role of an exofacial sulfhydryl group on the human erythrocyte hexose carrier. Above 1mm DTNB rapidly inhibited erythrocyte 3-O-methylglucose influx, but only to about half of control rates. Efflux was also inhibited, but to a lesser extent. Uptake inhibition was completely reversed by incubation and washing with 10mm cysteine, whereas it was only partially reduced by washing in buffer alone, suggesting both covalent and noncovalent interactions. The covalent thiol-reversible reaction of DTNB occurred on the exofacial carrier, since (i) penetration of DTNB into cells was minimal, (ii) blockade of potential uptake via the anion transporter did not affect DTNB-induced hexose transport inhibition, and (iii) DTNB protected from transport inhibition by the impermeant sulfhydryl reagent glutathione-maleimide-I. Maltose at 120mm accelerated the covalent transport inhibition induced by DTNB, whereas 6.5 m cytochalasin B had the opposite effect, indicating under the one-site carrier model that the reactive sulfhydryl is on the outward-facing carrier but not in the substrate-binding site. In contrast to glutathione-maleimide-I, however, DTNB did not restrict the ability of the carrier to reorient inwardly, since it did not affect equilibrium cytochalasin B binding. Thus, carrier conformation determines exposure of the exofacial carrier sulfydryl, but reaction of this group may not always lock the carrier in an outward-facing conformation.     

An absorbable catheter system for use in microvascular and peripheral vascular surgery: an experimental study in the canine.

An absorbable catheter for use in regional anticoagulation in microvascular and peripheral vascular surgery was studied in 20 sites in 10 adult beagle dogs to answer three questions: (1) Could the polyglycolic acid and trimethylene carbonate catheter withstand intraarterial pressures of infusion and completely absorb over a predictable time interval? (2) Could the catheter be filled with heparin and maintain patency for reuse after a 24-hour interval? (3) Could the catheter be placed in a side branch of a major artery and, after catheter dissolution, maintain long-term patency of the primary feeding artery? The catheters were completely absorbed from 24 to 34 weeks following implantation. The catheters were able to withstand intraarterial pressures, and no evidence of significant thrombosis of the primary feeding artery was seen in any animal studied. No complications of catheter leak, hematoma formation within the catheter placement sites, or sepsis were noted in any of the 20 catheter sites studied.     

Electron microscopic studies on liver 5-aminolaevulinate synthase

The structure of chick embryo liver 5-aminolaevulinate synthase has been examined by electron microscopic studies using negative staining. From the different projections of the enzyme particles observed in electron micrographs, a model for the enzyme molecule has been proposed. In this model, an enzyme molecule consists of two curved and identical subunits associated in opposite polarities. From the dimensions of an enzyme molecule subunit measured from electron micrographs, the relative molecular mass of each subunit is estimated to be 70 000.