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Biomedical subjects

J Plant

Publications and source records attributed to J Plant.

15 recordsLinked to original sources

Regional geochemical mapping and interpretation in Britain.

Regional geochemical atlases of Britain and the British North Sea prepared by the Institute of Geological Sciences are discussed with special reference to their environmental significance. Factors affecting the selection of sample types are considered, and sample preparation, analytical procedure and monitoring error discussed. Stream sediment is shown to be the optimum sample type for regional geochemistry in areas of upland Britain underlain by crystalline bedrock, although soils may provide the optimum sample medium in areas of intensive agriculture. Geochemical mapping of the continental shelf is based on superficial seabed material obtained by grab or cone dredge. Examples of geochemical maps of northern Scotland for several elements of environmental significance including Cu, Mo, Pb, and U are considered in relation to geology, topography, vegetation, land use and the chemistry of surface waters. Geochemical maps are shown to provide the best available source of information on chemical variations in bedrock, although there are many difficulties in relating geochemical or biological activity to the total trace element values. In any attempt to correlate trace element levels with disease, careful consideration must be given to factors affecting the availability and flux of the trace elements if meaningful associations are to be obtained. Geochemical maps of the North Sea indicate that the contents of Cu, Pb, Zn, Cd and Hg are uniformly low over most of the offshore area although higher concentrations occur in coastal samples. The highest concentrations of Cu, Pb and Zn occur off the Tyne estuary while the highest values for Cd and Hg occur further south.

Geography

Our strongest card.

Explore the source record for details and available documents.

Collective Bargaining

Locating salmonella resistance gene on mouse chromosome 1.

The inherited resistance of inbred mouse strains to Salmonella typhimurium injected subcutaneously has been reported to be controlled primarily by a single gene designated Ity. Resistant mice have the dominant allele Ityr and sensitive mice are homozygous for the recessive allele Itys. This paper describes studies undertaken to locate the gene using readily distinguishable phenotypes as chromosome markers. Appropriate F1 backcross and F2 generations of hybrids between resistant and susceptible inbred strains of mice, with or without the particular phenotypic markers, were tested both for susceptibility to salmonella sci and presence of the marker. Independent segregation of the characteristics eliminated all chromosomes except Chromosome 1. C57L mice resistant to S. typhimurium, Ityr Ityr and leaden, ln ln, located on Chromosome 1, were crossed with BALB/c mice sensitive to S. typhimurium and non-leaden. In the F2 generation mice, ln always segregated with Ityr. The presence of only one leaden mouse sensitive to S. typhimurium out of sixty leaden F2 mice tested linked Ityr closely with ln on Chromosome 1. This result will be of use in further experiments with hybrid populations by enabling us to predetermine resistance or sensitivity to S. typhimurium without infecting the mice, so permitting experiments on the nature of the inheritance in unsensitized mice.

Animals

Teaching hospital nurtures growth of community oncology clinics.

In the belief that primary cancer care, such as drug and radiation therapy, can be delivered by community hospitals close to patients' homes and families, University Hospital and the Boston University School of Medicine are helping to establish local oncology clinics. Educational services for community physicians, nurses, and social workers are also offered.

Ambulatory Care

Small firms look to hospitals for occupational health services.

Some hospitals are offering preemployment physicals, routine examinations, prompt work injury care, physician and nurse consultations and visits, and other services to small companies that cannot justify establishing in-house occupational helath units.

Hospital Bed Capacity, 300 to 499

Emergency/outpatient satellites serve as rural outposts.

Physician recruitment problems and sudden population growth placed a severe strain on several New Hampshire communities until civic and hospital leaders pooled resources to develop combined emergency/outpatient satellites. Range of services, staffing, operations, financing, and impact of the satellites are discussed in detail.

Community-Institutional Relations

Protective effects of a supernatant factor from Salmonella typhimurium on Salmonella typhimurium infection of inbred mice.

A supernatant factor prepared from 48-h cultures of Salmonella typhimurium has been used to immunize mice against subsequent challenge with normally lethal doses of S. typhimurium. The mouse strains used, C57BL and BALB/c, were sensitive to S. typhimurium with 50% lethal doses of less than 50 organisms. Two doses of supernatant factor, given intraperitoneally 20 days apart, protected mice against a subcutaneous challenge dose 10 days later of 100 50% lethal doses of S. typhimurium, resulting in 50 to 80% survival. The viable counts were reduced initially in organs of immunized mice compared with controls, and the multiplication of bacteria was delayed, although the final levels found in the organs would normally have been lethal. Protection obtained was specific for S. typhimurium in that no increased survival was shown after Salmonella enteritidis challenge of immunized mice. Although lipopolysaccharide was demonstrated in the supernatant factor, lipopolysaccharide alone did not protect challenged mice. Supernatant factor produced delayed-type hypersensitivity reactions in mice sensitized with nonlethal doses of Salmonella. The nature of the active factor, found to be partially protein, has yet to be elucidated.

Animals

Genetics of resistance to infection with Salmonella typhimurium in mice.

Eight strains of inbred mice fell into two sharply defined groups. Four strains (CBA, A/JAX, C3H/He, and DBA/2) were resistant (LD50, greater than 10(5)) to Salmonella typhimurium C5 given subcutaneously. The other four strains (Balb/c, C57BL, B10.D2 [new line], and DBA/1) were susceptible (LD50, less than 10). No intermediate resistance was seen. Examination of the F1, F2, and parental backcross generations bred from matings of CBA and Balb/c mice showed that resistance behaved as a simple Mendelian dominant. Resistance was not linked to H-2 genes, and no useful marker has yet been found. However, as previously demonstrated in the parent strains, resistance in the hybrids was related to the ability to produce a good delayed-type hypersensitivity reaction to an extract of S. typhimurium.

Animals