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Biomedical subjects

S M Thornton

Publications and source records attributed to S M Thornton.

12 recordsLinked to original sources
PubMed2001

Management of hepatitis B virus infections in two gibbons and a western lowland gorilla in a zoological collection.

Since 1996, three primates newly arrived at London Zoo have been found to be infected with hepatitis B virus. The species involved were white-cheeked gibbons (Hylobates leucogenys leucogenys and Hylobates leucogenys siki) and a western lowland gorilla (Gorilla gorilla gorilla). The protocols for the practical management of these cases, including the immunisation of susceptible non-human primates and the staff with recombinant hepatitis B vaccine are described, and the origin and evolution of hepatitis B infection in primates are discussed.

Animals↗
PubMed1998

Bacterial isolates from California sea lions (Zalophus californianus), harbor seals (Phoca vitulina), and northern elephant seals (Mirounga angustirostris) admitted to a rehabilitation center along the central California coast, 1994-1995.

In 2 yr of bacteriologic culturing of 297 California sea lions (Zalophus californianus), 154 harbor seals (Phoca vitulina), and 89 northern elephant seals (Mirounga angustirostris) stranded alive along the California coast, the most frequent isolates from inflammatory lesions in live animals were Escherichia coli, Streptococcus viridans, Listeria ivanovii, beta-hemolytic Streptococcus spp., and Enterococcus spp. This is the first report of L. ivanovii isolation from a marine mammal. The common isolates from lung and liver in animals dying during rehabilitation were E. coli, Salmonella spp., Klebsiella spp., Pseudomonas spp., Aeromonas spp., Proteus spp., and Staphylococcus aureus. The most common isolates from brain were Enterococcus spp., E. coli, Klebsiella spp., and Pseudomonas spp. Ocular lesions were seen most often in harbor seals and elephant seals, from which the isolates cultured included Pseudomonas spp., Enterococcus spp., Streptococcus viridans, E. coli, Staphylococcus aureus, Proteus spp., Morganella morganii, Moraxella spp., beta-hemolytic Streptococcus spp., and L. ivanovii. Nine different Salmonella serotypes were isolated from 49 animals; S. newport was the most common. These results should enable those working clinically with these species to make logical decisions in choosing initial antimicrobial therapy.

Abscess↗
PubMed1995

Extensive TCR junctional diversity of V gamma 9/V delta 2 clones from human female reproductive tissues.

Panels of gamma delta T cell clones bearing the V gamma 9/V delta 2 form of TCR were derived from human first trimester decidualized endometrium and cervix. Seventy-three percent of these clones expressed the human mucosal lymphocyte Ag HML-1 compared with only 14% of PBL V gamma 9/V delta 2 clones, indicating that most clones were derived from the tissue itself rather than contaminating peripheral blood. All 13 clones isolated expressed V gamma 9JPC gamma 1- and V delta 2(D)J delta 1-encoded receptors; TCR gamma and delta junctional regions from most of these were sequenced and analyzed, together with the TCR-delta junctional region of a sequence obtained from bulk CD3+ decidual leukocytes. There was considerable junctional diversity of both gamma- and delta-chains with a similar extent of germline V and J gene trimming and N-region nucleotide addition to that found in PBL V gamma 9/V delta 2 cells. Eight of eleven TCR-delta junctional sequences contained a strongly hydrophobic amino acid in position 97, as has been found in > 90% o V gamma 9/V delta 2 clones. Thymic V gamma 9/V delta 2 cells show much less junctional diversity and less pronounced selection at residue 97 of the delta-chain. Thus, unlike the mouse, gamma delta T cells from human female reproductive tissues exhibit extensive TCR junctional as well as combinatorial diversity. This suggests that V gamma 9/V delta 2 cells in these human tissues have undergone selective but diverse peripheral expansion in response to antigenic stimuli in a similar manner to those in peripheral blood.

Amino Acid Sequence↗
PubMed1995

The effects of centrally administered porcine relaxin on drinking behaviour in male and female rats.

Of the reproductive hormones it has been suggested that relaxin may play an important role in the increased sodium appetite of pregnancy. ICV injection of porcine relaxin caused water-replete male and female Wistar rats with access to water and 0.9% or 2.7% NaCl to drink on average about 3 to 8 ml of water within 1 h of injection. By 24 h the cumulative intake of water was no different from the control intake. The amounts of water drunk were similar after doses of 50, 100, 250 and 500 ng of relaxin. A dose of 5 ng was ineffective. Male rats generally drank more water than female rats after ICV injection of angiotensin or relaxin. Male SH rats which drink more water than male WKY rats in response to ICV angiotensin also drank more after ICV relaxin. Intakes of 0.9% or 2.7% NaCl were unaffected for up to 24 h after injection of relaxin, whereas angiotensin-injected rats showed a significant increase in 0.9% NaCl 1 h after injection though this difference was no longer evident in the 24 h cumulative intake. Relaxin did not cause any increase in NaCl intake in SH rats. Insulin, which is similar in structure and molecular weight to relaxin, was without effect on drinking when doses comparable to dipsogenically effective doses of relaxin were injected ICV. In male Wistar rats treated with DOCA for 5-15 days, relaxin retained its weak stimulatory action on water intake but did not affect NaCl intake despite the increased baseline NaCl intake during DOCA. These results indicate that relaxin is a dipsogen in the rat but that it seems to have little short-term effect on sodium appetite.

Animals↗
PubMed1993

T cell receptor junctional regions of V gamma 9+/V delta 2+ T cell clones in relation to non-MHC restricted cytotoxic activity.

Human gamma delta T cell clones having V gamma 9JP and V delta 2DJ1 T cell receptor (TCR) gene rearrangements were isolated form an individual donor and tested for non-MHC restricted cytotoxicity against the B lymphoblastoid cell line, BSM. Most clones were highly cytotoxic but 3/9 clones had very low activity, comparable to that of CD4+ alpha beta T cell clones. Although there was a tendency for clones with low cytotoxic function to produce high levels of interferon-gamma and tumor necrosis factor-alpha, this correlation was not complete. TCR gamma and delta junctional sequences were obtained and were found to be different for all clones. There were no consistent structural differences between gamma delta TCRs of cytotoxic and non-cytotoxic clones, but gamma or delta junctional regions of all three non-cytotoxic clones had unusual features. One clone had a particularly short gamma chain junctional sequence, one had a short delta chain junctional sequence and the third clone was the only one of the panel which failed to utilise the D delta 3 segment. If the gamma delta TCR is involved in target cell recognition in this model of non-MHC restricted killing, such variations in receptor structure may be sufficient to inhibit recognition and thereby reduce the cytotoxic capacity of a minority of V gamma 9+/V delta 2+ clones. Also, a panel of gamma delta T cell clones expressing V gamma 8/V delta 3 isolated from a different donor, were all highly cytotoxic against BSM, indicating that these target cells can be recognised by effector cells expressing a TCR other than the V gamma 9/V delta 2 receptor. The possible influence of other cell surface molecules on non-MHC restricted cytotoxic function is discussed.

Amino Acid Sequence↗
PubMed1989

Denver developmental activities: a preliminary report.

A study was undertaken to develop activity sheets that can be given to parents at the time of child health maintenance visits. A series of 200 activities for parents to undertake with their children were arranged into 11 age groups and four areas: self-care and socialization, speech, small muscle skills, and large muscle skills. A national field test involved 53 private and public practices already using a parent-answered developmental questionnaire. The practices gave the Denver Developmental Activities and survey questionnaires to parents, and completed professional survey questionnaires. Fifty-one professional questionnaires and 79 parent questionnaires were returned. The professionals liked the Activities and did not feel that they slowed their practices. Parents found the Activities enjoyable and easy to understand. Less educated parents reported that the Activities increased their knowledge and prompted them to discuss child development issues with their child's health provider. This survey is considered preliminary, since it was limited to health practices already manifesting interest in child development, and it is not known what percent of parent questionnaires were returned. The latter point precludes one from making generalizations to a larger population.

Adult↗
PubMed1988

Validation of key Denver Developmental Screening Test items: a preliminary study.

Three sequential studies were undertaken to identify a subset of 39 key Denver Developmental Screening Test (DDST) items covering the ages from birth to 6 years. The first study used binary integer programming with a sample of 2343 children evaluated with the DDST in Denver's Neighborhood Health Program. It identified 35 DDST items that would identify 100% abnormal and 97.9% abnormal and questionable DDSTs. A further validation with 113 Pitt County, North Carolina, children indicated that the addition of four more DDST items to the previous 35 would identify 100% abnormal and 92.6% abnormal and questionable DDSTs. A third study cross-validating the 39 items with a sample of 180 children at "high risk" identified 100% abnormal and 91.7% abnormal and questionable DDSTs. The 39 key DDST items ranged throughout the entire age span and among the DDST's four sectors. Use requires the administration of approximately four items at any one age, on average. Those children with suspect scores on the key DDST items (about 19% of a low-income population) should be screened with the remainder of the DDST to decrease overreferrals. For accuracy, the key DDST items must be administered in the manner prescribed in the DDST manual.

Child↗
PubMed1988

Common pitfalls in the evaluation of developmental screening tests.

Wilson has written that screening puts a responsibility on the physician to provide some benefit to the person being screened. He made the distinction between the physician who is confronted by a patient with a problem that the physician may attempt to cure with unproved means, on one hand, and persons who mount community screening programs with unproved procedures on the other. He considers the former to be ethical and the latter unethical. Similarly, we consider the failure to avoid pitfalls--such as improper screening test administration, failure to use reliable outcome criteria, making inappropriate (although well-intentioned) predictions, and making inappropriate generalizations or drawing inappropriate conclusions--to be unethical. The pitfalls jeopardize the achievement of the desired outcome by screening programs. They also lead to inappropriate conclusions and possibly, therefore, to the use of inappropriate tests. If the scientific community does not take steps to avoid such pitfalls in developmental screening, it invites those who make health care decisions to eliminate such screening or to mandate procedures which may not be scientifically sound. Neither of these alternatives is acceptable. The only alternative, first, is to ensure that one avoids common pitfalls when screening in one's own practice and, second, to be on guard against developmental screening studies and reports that fail to avoid these errors.

Child↗
PubMed1987

Revision of Denver Prescreening Developmental Questionnaire.

The Denver Prescreening Developmental Questionnaire (PDQ), a parent-answered questionnaire, has been revised to extend the age of children who can be screened to those from 6 years down to birth, to make the test items more challenging for children and more informative for parents, and to make it easier for professionals to compare a child's performance with Denver Developmental Screening Test (DDST) norms. This Revised PDQ (R-PDQ) identified 84% of nonnormal DDST results. Test-retest reliability over 1 week was 94.1%, and parent-teacher agreement was 83%. A field test of the R-PDQ, conducted in a variety of settings with 1434 children, revealed that suspect scores on first-stage screening varied with the setting, from 15.6% in private pediatric practices to 50.5% in Head Start and urban day care centers. Parents found the R-PDQ interesting and easy to complete; health professionals found it economical and easy to interpret. We recommend that the R-PDQ be coupled with a brief developmental examination, and that the R-PDQ be used in busy office settings and community mass screening programs.

Child↗