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Biomedical subjects

S M James

Publications and source records attributed to S M James.

16 recordsLinked to original sources
PubMed2004

Effects of multiple routes of cadmium exposure on the hibernation success of the American toad (Bufo americanus).

The effects of multiple routes of cadmium exposure on juvenile American toads (Bufo americanus) were evaluated using environmentally relevant concentrations. During or after exposure, toads were individually hibernated for 172 days at approximately 4degreesC. The following experiments were conducted: (1) dermal exposure (hibernation in soil contaminated with up to 120 microg Cd/g (dry weight)); (2) injection exposure (single injection with cadmium to achieve a maximum whole-body nominal concentration of 3 microg Cd/g (wet weight) 12 days before hibernation in uncontaminated soil); and, (3) oral exposure (feeding with mealworms containing < or =16 microg Cd/g (dry weight) for 50 days before hibernation in uncontaminated soil). We hypothesized that sublethal levels of cadmium would become lethal during hibernation because of combined chemical and cold stress. No prehibernation mortality occurred in the injection and oral exposure studies. There was a significant treatment effect on whole-body cadmium concentration in toads orally or dermally exposed and on percent of cadmium retention in toads orally exposed. There was also a trend of increased time-to-burrowing and more toads partially buried with greater cadmium concentration in the dermal study, which indicated avoidance. In all 3 experiments, no significant differences were found among cadmium treatments in hibernation survival, percent of mass loss, or locomotor performance. However, toads fed mealworms averaging 4.7 microg Cd/g (dry weight) had only 56% survival compared with 100% survival for controls. Although our results suggest that environmentally relevant levels of cadmium do not pose a great risk to American toads, factors such as soil type or prey species may increase cadmium bioavailability, and other amphibian species may be more sensitive to cadmium than B. americanus.

Administration, Oral↗
PubMed1994

Recruiting and employing foreign nurse graduates in a large public hospital system.

Recruiting foreign nurse graduates (FNGs) is one way hospitals--particularly those in the nation's inner cities--are responding to the periodic and cyclic shortages that characterize the labor market for registered nurses. Until now, little was known about the overall efficacy of this strategy. This article reports the findings of an 18-month study of the recruitment and employment of FNGs by the New York City Health and Hospitals Corporation. Although considerably more expensive to recruit than domestic nurses, FNGs have higher retention rates than U.S.-educated nurses and possess other characteristics that make them desirable recruits for hospitals experiencing a nursing shortage.

Data Collection↗
PubMed1992

Nurses' job satisfaction: are there differences between foreign and U.S.-educated nurses?

This article reports the results of a job satisfaction survey administered to foreign-educated and U.S. nurses at six New York City public hospitals. Although a comparison of results for foreign-educated nurses on temporary visas (N = 322) and U.S. nurses (N = 535) revealed demographic, education and work differences, no differences in level of satisfaction were found between the two groups. Cultural and work status differences that may have affected these results are discussed.

Adult↗
PubMed1991

Phenotype and functional activity of tumor-infiltrating lymphocytes isolated from immunogenic and nonimmunogenic rat brain tumors.

The purpose of the present study was to define the immunogenicity of two transplantable rat gliomas, designated F98 and D74, and to relate this to the phenotype and functional activity of tumor-infiltrating lymphocytes (TIL). Fischer rats, immunized with irradiated F98 tumor cells and challenged with intracerebral implants of ten F98 cells, had a median survival time of 49 days compared to 36 days for nonimmunized controls. In contrast, no statistically significant increases in survival times were noted in animals similarly immunized and challenged with the D74 tumors. No in vivo protection could be demonstrated in animals immunized and cross-challenged with either F98 or D74 glioma cells. Lymph node lymphocytes and TIL, isolated from animals immunized and challenged with F98 cells, were more cytolytically active than effector cells obtained from D74-immunized animals. Phenotypes of TIL isolated from intracerebral F98 gliomas of immunized rats were 52% OX-8+ and 21% W3/25+ compared to 31% OX-8+ and 19% W3/25+ for D74-immunized animals. Cytolytic activity against glioma targets was mediated by OX-8+ TIL, as determined by cell depletion experiments. Limiting dilution analysis showed that cytolytic T-lymphocyte precursors were present in TIL of F98 gliomas of immunized rats at a frequency of 1/3547 and were specific for F98 targets, while natural killer cell-like activity was low. Our data indicate that the F98 glioma was more immunogenic than the D74 glioma, as evidenced by increased numbers and activity of cytolytic effector cells and their precursors among TIL. This may explain in part the longer survival times observed in immunized animals challenged intracerebrally with the F98 gliomas compared to D74-immunized and -challenged hosts.

Animals↗
PubMed1991

The prevention of dental caries by BLIS-mediated inhibition of mutans streptococci.

Many of the strategies that have been formulated to decrease the incidence of dental caries have focused upon attempting to reduce either the numbers or the acidogenic activities in dental plaque of the mutans streptococci. In recent years there has been a growing interest in a new method of caries control which depends upon exploiting the ability of certain bacteria to produce antibiotics called bacteriocin-like inhibitory substances (BLIS) with killing activity for mutans streptococci. The approaches under investigation include either the regular oral administration of the purified BLIS or the genetic modification of existing plaque bacteria such that they produce the antimutans BLIS in situ.

Antibiosis↗
PubMed1987

Chloramphenicol-resistant Salmonella newport traced through hamburger to dairy farms. A major persisting source of human salmonellosis in California.

Animal-to-human transmission of drug-resistant salmonella and the role of antimicrobial use in food animals in the emergence of these bacteria are controversial subjects. Investigation of a 4.9-fold increase in Salmonella newport isolations from Californians in 1985 showed that 87 percent of the isolates had an unusual antimicrobial-resistance pattern (including chloramphenicol resistance) and a single, identical plasmid. Interviews of 45 patients and 89 matched controls in Los Angeles County showed that illness was associated with penicillin or tetracycline use during the month before onset (P less than 0.001) and with eating ground beef during the week before onset (P = 0.052). The epidemic strain was isolated from hamburger products eaten by cases, abattoirs where the animals from which the meat came were slaughtered, dairies that sent cows for slaughter on days when culture-positive products were processed, and ill dairy cows. Isolation of salmonella from beef carcasses in abattoirs correlated with the proportion of dead or moribund animals received for slaughter (r = 0.60, P less than 0.05). Isolation of chloramphenicol-resistant salmonella from dairy farms was associated with the use of chloramphenicol at those dairies. We conclude that food animals are a major source of antimicrobial-resistant salmonella infections in humans and that these infections are associated with antimicrobial use on farms.

Abattoirs↗
PubMed1987

Relationship of bacteriocin-like inhibitor production to the pigmentation and hemolytic activity of mutans streptococci.

An inhibitor production typing (P-typing) scheme originally devised for hemolytic streptococci of Lancefield groups A-G has been successfully applied to 35 mutans streptococcus isolates recovered from plaque cultures of 60 Dunedin schoolchildren. Thirteen different P-type designations were identified. Although 11 (31%) of the isolates failed to produce detectable inhibitory activity on the conventional blood agar medium used for P-typing, four of these isolates were inhibitor-positive on Trypticase Soy agar supplemented with 2% yeast extract and 0.5% calcium carbonate (TSYCa). Four mutans strains displayed strong beta-hemolysis on Columbia agar base containing human blood when incubated in a 5% CO2 in air atmosphere. Three of these also produced weak beta-hemolysis on sheep blood-supplemented medium and were further distinctive in that they were the only inhibitor P-type 767 strains to be detected in the present study. Five mutans isolates were pigment producers and this property seemed to occur independently of both the beta-hemolytic activity and the P-type designation. Upon testing an additional collection of 18 mutans strains of various serotypes, only seven (39%) were inhibitor-positive. However, three of the four serotype c strains were inhibitor producers. Two strains of serotype d and one of serotype g were more hemolytic on sheep than on human blood agar medium. In general, it seems that the most common human mutans streptococci (serotype c strains) are more likely than are other mutans strains to produce bacteriocin-like inhibitory activity and to be hemolytic for human rather than sheep erythrocytes.

Bacteriocins↗
PubMed1982

Decrease in ribosomal proteins 1, 2/3, L4, and L7 in Drosophila melanogaster in the absence of X rDNA.

The rRNA genes (rDNA) in Drosophila melanogaster are found in two clusters, one on the X and one on the Y chromosome. We have compared the ribosomal protein composition of wild-type Oregon-R flies containing both X-linked and Y-linked rDNA with that of flies containing only the Y-linked rDNA by two-dimensional polyacrylamide gel electrophoresis. Four basic proteins (1, 2/3, L4, and L7) normally present in wild-type flies were either electrophoretically not detectable (1, 2/3, and L4) or marginally detectable (L7) in flies with only Y-linked rDNA. No additional proteins were observed in these flies. However, immunodiffusion assays using specific antibodies raised against purified protein L4 confirmed that L4 was present but in relatively lower amounts in these Y-linked rDNA flies. An investigation was carried out to determine whether these electrophoretically undetectable proteins were more readily lost during ribosome preparation and hence were not readily detectable in the 80S particles by gel electrophoresis or whether they had been modified. Thus the proteins in the post-ribosomal cell supernatant and the high salt sucrose gradient were analyzed by two-dimensional gel electrophoresis and immunochemical assays with antibodies raised against protein L4 and total 80S ribosomal proteins. The experimental evidence indicates that there is a small amount of protein L4 and probably proteins 1, 2/3, and L7 in flies with only Y-linked rDNA but significantly less of these proteins than in wild-type flies.

Animals↗