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D Bennett

Publications and source records attributed to D Bennett.

At least 217 records · Page 12Linked to original sources
PubMed1988

Intra-H-2 recombination in t haplotypes shows a hot spot and close linkage of 1tw5 to H-2K.

The embryonic lethal mutation in the tw5 haplotype is known to map near the H-2K region of the mouse major histocompatibility complex. Additional data obtained by classical genetic methods demonstrate that the tw5 lethal gene is effectively inseparable from H-2K. No recombinants were found between H-2K and tw5 in a sample representing over 1200 mice. On a statistical basis tw5 must be less than 250 kb from the H-2K gene. In the course of these mapping studies we obtained a set of 11 intra-H-2 recombinants. We have analyzed these and three others derived from another experiment to define their breakpoints as precisely as possible. Southern blot analysis with molecular probes to the D, S, I, and K regions of the H-2 complex defines seven recombinations between the D and S regions, two between S and I, none within the I region, and five events between I and K. The last category was studied in finer detail by developing unique copy probes to the I-K boundary region. Two of the five events occurred within probably less than 6 kb of each other: these two recombinants define the centromeric limit of the location of the tw5 gene within the H-2K region. The other three I-K recombinants occurred in at least two other nearby locations. Altogether at least three, and probably all five I-K recombinants fall within a 45 kb recombinational hot spot recently identified in Mus musculus castaneus.

Animals↗
PubMed1988

Hemodynamic response to treadmill exercise in normal volunteers: an assessment by Doppler ultrasonic measurement of ascending aortic blood velocity and acceleration.

Accurate assessment of ascending aortic blood velocity indices and reproducibility of a Doppler ultrasonic system during exercise were determined; the Doppler technique was then used to assess the effects of age, sex, and beta blockade on exercise hemodynamics. Doppler-determined velocity correlated well with an invasive electromagnetic system. Reproducibility of Doppler variables during three exercise tests was high (coefficient of variation less than 10%) and did not deteriorate appreciably with exercise. Peak velocity (PV) and maximum acceleration (MA) were inversely related to age, the relationship being more significant during exercise, whereas the systolic velocity integral showed no such relationship either at rest or during exercise. Doppler variables showed no difference between sexes, except at high levels of exercise. Beta blockade markedly attenuated the exercise response as shown by significant decreases in both MA and PV during exercise. The Doppler velocity data presented in this study provide a reference against which previously documented changes in exercising ischemic patients can be better related.

Adult↗
PubMed1988

Research skills and the research environment: a needs assessment of allied health faculty.

Allied health faculty are expected to successfully compete with other academic faculty in the research arena, yet many feel unprepared for this role. Most faculty have been trained as clinicians and, thus, bring to academe few skills in research design and methodology. A national study was conducted to assess the research skills and the research milieu of allied health faculty across eleven disciplines. Data are presented from 2,187 survey responses. Unmet needs included skills in obtaining funding, statistical analysis of the data, and publishing research results. Major barriers to research included the undervaluing of research relative to education and service, the lack of financial and administrative support, the absence of professional resources, and the generally low priority given research. Faculty with earned doctorates perceived their research environments more favorably and had fewer gaps in research skills than did faculty with a bachelor's or master's degree.

Allied Health Personnel↗
PubMed1988

Research productivity profile of allied health faculty.

Many allied health faculty are expected to obtain graduate degrees and engage in scholarly activity to advance knowledge in their professions and fulfill the research mission of their academic institution. A national study of ten allied health disciplines was conducted to assess the level of allied health research productivity and to determine the relationship between the amount of research and faculty characteristics. Research productivity included the number of major paper presentations and research publications, number of times served as project principle investigator, and the time devoted to research per week. Faculty characteristics were the type of employing institution, and the academic degree, rank, and tenure status of the faculty member. Data from 2,187 survey respondents indicated that faculty who are employed by four-year research universities, possess earned doctorates, hold the rank of professor, and are tenured had significantly higher levels of research productivity.

Allied Health Personnel↗
PubMed1987

The molecular organization of the H-2K region of two t-haplotypes: implications for the evolution of genetic diversity.

The genetic diversity between the t12 and tw5 haplotype chromosomes was studied by analyzing the molecular organization of the H-2K region. Twenty-one cosmid clones spanning over 150 kb of the H-2K region of both t-haplotypes were defined, and high resolution restriction maps were determined. Detailed comparison of the t12 and tw5 restriction maps revealed the following. (i) The H-2K regions of both t-haplotypes retain a very similar molecular organization to that reported for B10, BALB/c and AKR. The nucleotide sequence diversity estimated from restriction site polymorphism is 0.68% between the t12 and tw5 haplotypes; these two t-haplotypes are no more similar to one another than BALB/c is to AKR. (ii) Genetic recombination is strongly implicated in generating H-2 polymorphism. (iii) Genetic polymorphisms, defined as small restriction fragment size differences, are observed at multiple sites along the H-2K region. An Alu-like B2 sequence and BAM5-R homologous sequence were identified as the inserted/deleted DNA segments of two of these sites, suggesting that insertion/deletion of mobile elements is a general mechanism for generating genetic diversity.

Animals↗
PubMed1987

The direct measurement of plasma colloid osmotic pressure is superior to colloid osmotic pressure derived from albumin or total protein.

Plasma colloid osmotic pressure (COP) has been calculated from both serum albumin concentration and plasma total protein concentration. These values have been compared to those measured directly using a membrane-transducer oncometer in a group of normal subjects, in a group of critically-ill patients with a variety of primary diagnoses and in a group of hypovolaemic patients before and after plasma volume replacement with 6% hydroxyethyl starch solution. In the normal samples, COP calculated from albumin (COPalb) underestimated the measured COP (COPm) by mean of 2.0 mmHg (p less than 0.002), with correlation coefficient r = 0.39(n/s). Similarly, the COPalb underestimated COPm by a mean of 5.7 mmHg (p less than 0.001) in the critically ill patient group; r = 0.38 (p less than 0.02). Furthermore, in the patients receiving plasma volume replacement serum albumin concentration fell by 13.1% (p less than 0.001) whilst COPm increased by 11.5% (p less than 0.002). In the normal subjects COP calculated from total protein concentration (COPtp) underestimated the COPm by 1.5 mmHg (p less than 0.02) with r = 0.65 (p less than 0.01). Conversely, in the patient samples, mean COPtp overestimated COPm by 3.5 mmHg (p less than 0.001) with r = 0.73 (p less than 0.002). We conclude that COPalb is an inadequate estimate of COPm particularly in patients where its use may have important clinical consequences. COPtp provides a reasonable estimate of COPm in normal subjects but in patients samples, where albumin: globulin ratio is low COPtp overestimates substantially in many cases. We advocate the direct measurement of COP in critically-ill patients.

Adult↗
PubMed1987

The laboratory identification of serum antinuclear antibody in the dog.

An indirect immunofluorescence test with sections of rat liver as a substrate, proved useful in detecting antinuclear antibodies (ANA) in the dog. A specific anti-canine IgG reagent conjugated with fluorescein isothiocyanate was used. A proportion of normal dogs gave positive reactions at low titres. The presence of ANA was one of the criteria used to diagnose canine systemic lupus erythematosus. Some dogs within a general hospital population were also positive for the auto-antibody. The indirect immunofluorescence test with Trypanosoma brucei as a substrate was insensitive. The LE-cell test was laborious and insensitive. A commercial latex slide agglutination test used for detecting ANA in man gave false positive and false negative results in the dog. A commercial radioimmunoassay used in man gave many false positive results. A similar assay with synthetic DNA gave encouraging results and is worthy of further study.

Animals↗
PubMed1987

The laboratory identification of serum rheumatoid factor in the dog.

A modified Rose-Waaler test with sheep red blood cells coated with canine IgG was found satisfactory for detecting rheumatoid (antiglobulin) factor (RF) in dog serum. Low titres of RF were found in some normal dogs. Most dogs with rheumatoid arthritis were positive for RF at titres of 1 in 40 or greater. A small proportion of dogs with diseases other than polyarthritis were also positive for RF. A commercial slide agglutination test used for detecting human RF was unsatisfactory for the dog, giving false positive and negative reactions. A latex tube agglutination test with latex particles coated with dog IgG was developed but non-specific agglutination was a constant technical problem.

Animals↗
PubMed1987

Fate of 2,5,4'-trichlorobiphenyl in outdoor ponds and its uptake via the food chain compared with direct uptake via the gills in grass carp and rainbow trout.

A field experiment was carried out to investigate the fate and the extent to which food chain transfer of a PCB congener (2,5,4'-trichlorobiphenyl; 3-CB) could affect its potential for bioaccumulation. Three 35-m3 ponds were each stocked with 25 rainbow trout (a carnivore) and 20 grass carp (a herbivore). 3-CB was supplied to each pond at a nominal concentration of 14 micrograms liter-1. Samples of water, sediment, grass carp, rainbow trout, aquatic plants, and invertebrates were removed at intervals from 0 to 28 days after treatment and residues of 3-CB were determined using gas-liquid chromatography with electron-capture detection. The fate of 3-CB in the ponds was determined by transport rather than degradation processes. Evaporation accounted for 86-87% loss and sorption onto sediment and biota for 11-12% loss of 3-CB from the pond water after 28 days. The kinetics of transport between water, air, sediment, and biota were studied after fitting the data to a three-compartment model. This model was used to calculate rates of evaporation (ke) and sorption. The calculated value for ke was in good agreement with predictions based on fundamental relationships between Henry's constant, windspeed, and ke. Residues of 3-CB in rainbow trout accumulated to a significantly greater extent (P less than 0.05) than in grass carp. This difference could not be explained by differences in growth rates, distribution of lipids, or by a difference in rates of metabolism. The most plausible explanation is that there was a difference in accumulation of 3-CB residues via the food chain. This experimental work supports the conclusion, suggested by a modeling approach of other workers, that food chain accumulation of PCBs can be an important route for uptake when environmental concentrations are very low.

Animals↗
PubMed1987

Conditioned activity and the interaction of amphetamine experience with morphine's activity effects.

This experiment assessed the transfer effect of Pavlovian conditioning with d-amphetamine sulfate (1 mg/kg) on morphine's activity effects. Prior experience with amphetamine resulted in higher levels of activity when challenged with morphine (10 and 20 mg/kg). This interactive effect of amphetamine, however, was present only in those animals who had experienced amphetamine paired with the activity test situation. Animals who had received equivalent doses of amphetamine unpaired with the testing environment did not differ from drug-naive control animals. Analysis of predrug activity levels revealed a conditioned activity response in paired animals compared to the controls. These findings suggest that the response interaction between drug conditioned responses and drug unconditioned responses is an important determinant of cross-drug effects between drugs of different pharmacological classes.

Animals↗
PubMed1987

Polymorphism and linkage of the alpha A-crystallin gene in t-haplotypes of the mouse.

Restriction fragment polymorphisms were used to order the alpha A-crystallin locus (Crya-1) relative to other genes in mouse t-chromatin and to investigate the relatedness of alpha-A-crystallin sequences among different t-haplotypes. Analysis of DNA from t-recombinant mice mapped Crya-1 to the K end of the H-2 complex and within the distal inverted region characteristic of t-haplotypes. Hybridization with Crya-1 cDNA revealed three distinct phenotypic groups among the 17 different t-haplotypes studied. A majority (9 of 17) of the t-haplotypes were classified into a novel group (Crya-1t) characterized by restriction fragments apparently unique to t-chromosomes and therefore thought to contain alpha A-crystallin sequences descended from the original t-chromosome. A second group of t-haplotypes had restriction fragment patterns indistinguishable from those observed among many common inbred strains of mice of the Crya-1a type, and a third restriction fragment pattern, observed only in the tw121 haplotype, was indistinguishable from the fragment pattern for C3H/DiSn (Crya-1b) and several other inbred strains of mice. Thus, with respect to sequences around the Crya-1 locus, different t-haplotypes show restriction fragment polymorphisms, some of which are comparable to those found in wild-type chromosomes and provide further evidence for genetic heterogeneity in DNA from the distal region of t-haplotypes.

Animals↗