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Biomedical subjects

B Watson

Publications and source records attributed to B Watson.

At least 37 records · Page 2Linked to original sources
PubMed1997

Travel with infants and children.

This article reviews the special needs of infants and children when traveling abroad. It addresses the importance of planning ahead, obtaining immunizations, and assessing possible risks while traveling. Also, this article reviews types of disease that can be acquired during travel and the follow-up care of children when they return home.

Aftercare↗
PubMed1997

Low levels of cardiovascular risk factors and coronary heart disease in a UK Chinese population.

OBJECTIVE: To compare the prevalence of cardiovascular risk factors and coronary heart disease in Chinese and Europid adults. DESIGN: Population based, cross sectional survey. SETTING: Newcastle upon Tyne, UK, 1991-93. SUBJECTS: Altogether 380 Chinese and 625 Europid adults, aged 25-64 years. MAIN OUTCOME MEASURES: Fasting lipid levels, blood pressure, body mass index (BMI), the proportions who smoked, and the prevalence of coronary heart disease based on the Rose angina questionnaire and major electrocardiographic abnormalities on resting 12 lead electrocardiogram (Minnesota codes 1.1-1.2). All figures were age adjusted to the 1991 England and Wales population. RESULTS: Altogether 183 and 197 Chinese, and 310 and 315 Europid men and women respectively were seen. Compared with Europid men, Chinese men had a lower mean total cholesterol concentration (5.1 versus 5.6 mmol/l, p < 0.001) and LDL cholesterol (3.2 versus 3.6 mmol/l, p < 0.001); lower BMI values (23.8 versus 26.1 kg/m-2, p < 0.001); and smoked less (23% versus 35%, p < 0.01)). Compared with Europid women, Chinese women also had lower mean lipid levels (total cholesterol: 4.9 versus 5.4 mmol/l p < 0.001, LDL cholesterol: 2.8 versus 3.1 mmol/l p < 0.001); BMI values (23.5 versus 26.1 kg/m-2, p < 0.001); and far fewer were smokers (1.4% versus 33%, p < 0.001). Chinese women, however, had higher mean systolic (121 versus 117 mmHg, p > 0.05) and diastolic (75 versus 68 mmHg, p < 0.001) blood pressures. The prevalence of coronary heart disease was significantly lower in Chinese than Europid men (4.9% versus 16.6%, p < 0.001) but not significantly different in women (7.3% versus 11.1%, p = 0.16). CONCLUSION: Strategies for UK Chinese are needed to maintain this favourable risk factor profile and prevent any potential increase in the risk of coronary heart disease associated with increasing acculturation.

Adult↗
PubMed1997

Immunogenicity of hepatitis B vaccine in preterm infants.

OBJECTIVE: To determine the immunogenicity of hepatitis B vaccine in preterm infants when the first dose of vaccine is delayed until hospital discharge. METHODS: One hundred two preterm infants (23 to 36 weeks gestational age) born to hepatitis B surface antigen-negative mothers were enrolled. Immunization was initiated just before hospital discharge with subsequent doses 1 and 6 months later. Serum specimens were obtained before the administration of each vaccine dose and 3 months after the last dose and were tested for antibody to hepatitis B surface antigen (antiHBs). RESULTS: Eighty-seven infants (85%) completed the study. Ninety percent (n = 78) of infants who completed the study seroconverted (antiHBs > or = 10 mIU/mL); 10% (n = 9) remained seronegative at study completion. The geometric mean antibody titer to hepatitis B surface antigen for infants who seroconverted was 200 mIU/mL. Nonresponders (NR) differed from responders (R) in birth weight (NR = 2090 g, R = 1560 g) gestational age (NR = 33 weeks, R = 31 weeks), and weight gain before vaccine initiation (NR = 244 g, R = 633 g). There were no differences in weight or age at vaccine initiation, Apgar scores, interval between vaccine doses, or bacterial infections, steroid use, or transfusions before vaccine initiation. CONCLUSIONS: Ninety percent of preterm infants responded to hepatitis B vaccine when the first dose of vaccine was delayed until hospital discharge. Nonresponders were more likely to be preterm infants of higher birth weight and higher gestational age, and to have gained less weight before vaccine initiation.

Gestational Age↗
PubMed1996

First prenatal diagnosis of the carnitine transporter defect.

We report the first attempt at prenatal diagnosis of the carnitine transporter defect in a fetus at high risk of having the disorder. Analysis of cultured CVS after prolonged culture predicted that the fetus was not affected but might be heterozygous for the carnitine transporter defect, but chromosome 15 satellite DNA markers showed no paternal contribution, suggesting that the CVS cells assayed were of predominantly maternal origin. Subsequent assay of cultured amniocytes predicted that the fetus would be affected, and this was confirmed in the newborn period. We conclude that prenatal diagnosis of the carnitine transporter defect is possible, but where results depend on extended culture of CVS, molecular studies should be performed to confirm genetic contributions from both parents.

Carnitine↗
PubMed1996

A chimeric analysis of the opioid receptor domains critical for the binding selectivity of mu opioid ligands.

The mu opioid receptor plays a key role in mediating the physiological, pharmacological, and behavioral effects of endogenous opioids and of opiate drugs such as morphine and heroin. This study examines the structural features critical to the selective binding of mu ligands to the mu receptor as opposed to the other two highly homologous opioid receptors, delta and kappa. We use a series of chimeric constructs between the mu and either the delta or the kappa receptors to investigate the structural bases of binding selectivity of multiple classes of mu-selective ligands. Our results demonstrate that a region comprising the sixth transmembrane domain and the third extracellular loop is critical for the mu/kappa discrimination by all mu-selective ligands. This region is also critical for mu/delta discrimination by the mu antagonists. However, mu agonists, particularly the peptides, exhibit more complex interactions, often relying on the N-terminal region surrounding the first extracellular loop for mu/delta discrimination. Thus, the same mu peptide ligand depends on different parts of the receptor to discriminate between mu and delta receptors on the one hand and mu and kappa on the other. In general, antagonists show the most consistent discrimination mechanisms regardless of construct, whereas agonists, particularly peptides, achieve selectivity by interacting with numerous domains of the receptors.

Animals↗
PubMed1996

Treatment planning for parotid sparing in the patient requiring bilateral neck irradiation.

The use of three dimensional (3-D) planning techniques for treatment of head and neck cancers has primarily been used in cases which require only unilateral neck irradiation. However, tumors that require bilateral neck irradiation are commonly managed with parallel opposed treatment portals. A common morbidity associated with this standard form of treatment is xerostomia. In an effort to reduce the incidence of this debilitating side effect, a protocol has been developed which attempts to balance effective tumor control with preservation of salivary flow. Key to this protocol is the use of 3-D treatment planning. The close proximity of the targeted tissues to critical structures and the related dose requirements and/or restrictions of these tissues often require the treatment planner to utilize "non-standard" approaches to achieve the unique dose distributions necessary to meet protocol eligibility. This may include treatment planning options such as non-coplanar, non-axial beams; and modulation of beam intensity.

Head and Neck Neoplasms↗
PubMed1996

A three-dimensional approach for re-irradiation of recurrent colorectal adenocarcinoma.

A large number of patients with resected rectal cancer will develop a symptomatic pelvic recurrence despite previous adjuvant radiation therapy. Re-irradiation after previous high dose radiation therapy carries an increased risk of complications in the normal tissues of the pelvis. However, other treatment modalities are not likely to provide a palliative benefit. Previous studies have shown that re-irradiation may be feasible and may palliate the patient. As minimal data is available on the toxicity of additional radiation therapy, this approach would be considered only when there is no other alternative for effective therapy and in the face of progressive and severe symptoms. With the use of three dimensional (3-D) treatment planning, portals can be designed to limit dose to previously irradiated critical structures while minimizing the risk of treatment related complications.

Adenocarcinoma↗
PubMed1996

Safety and immunogenicity of one vs. two injections of Oka/Merck varicella vaccine in healthy children.

OBJECTIVE: To compare the safety and immunogenicity of a one- vs. two-dose regimen of Oka/Merck varicella vaccine in approximately 2000 healthy children 12 months to 12 years of age. METHODOLOGY: Subjects with a negative history of varicella were randomized to receive either one or two injections of the vaccine given 3 months apart and were followed for clinical reactions and serologic response (glycoprotein-based enzyme-linked immunosorbent assay). RESULTS: Both one- and two-dose vaccine regimens were generally well-tolerated. The incidences of varicelliform rash and fever were less frequent after the second injection. However, a slight increase in the incidence of injection site reactions was noted after the second injection; these were generally mild. Seroconversion rates by glycoprotein-based enzyme-linked immunosorbent assay were 98.2% (1700 of 1731) after one injection and 99.9% (717 of 718) after two injections. A significant (P < 0.001) boost in geometric mean titers was observed in children who received a second injection of vaccine 3 months after the first injection. Of the children who seroconverted at 6 weeks postregimen (one or two doses as assigned), 99.8% (528 of 529) of the one-dose group and 99.8% (473 of 474) of the two-dose group maintained antibody to varicella at 1 year with geometric mean titers of 19.5 and 31.2, respectively. CONCLUSIONS: Administration of a one- or two-dose regimen of the live Oka/Merck varicella vaccine (VARIVAX) is immunogenic and is generally well-tolerated in healthy children 1 to 12 years old. Antibody to varicella persists in > 99% of vaccinees 1 year after vaccination regardless of a one- or two-dose regimen. Long-term follow-up studies of this cohort of children may determine whether a two-dose regimen offers superior protection against chickenpox.

Antibodies, Viral↗
PubMed1996

Genetic association of 11 beta-hydroxysteroid dehydrogenase type 2 (HSD11B2) flanking microsatellites with essential hypertension in blacks.

11 beta-Hydroxysteroid dehydrogenase type 2 (11 beta-HSD2) specifically modulates access of the mineralocorticoid aldosterone to the kidney mineralocorticoid type 1 receptors in a physiological environment in which there is a molar excess of cortisol. Cortisol and aldosterone have similar affinities for mineralocorticoid receptors. Mechanistically, 11 beta-HSD2 converts cortisol to cortisone. The other known isoform, 11 beta-HSD1, not only catalyzes the cortisol to cortisone reaction but also the reverse reaction, making it unlikely to play an important role in modulating the access of aldosterone to mineralocorticoid receptors. Mutations in the HSD11B2 gene (both exonic and intronic) have been demonstrated to cause reduced activity of this enzyme in the syndrome of apparent mineralocorticoid excess, a rare autosomal recessive disorder. We hypothesized that this locus is also involved in the etiology of essential hypertension. To test this locus and flanking chromosomal regions for allelic association and genetic linkage to essential hypertension, it is necessary to have informative genetic markers. To this end, we have refined the localization of 11 beta-HSD2 to 16q22.1. We genotyped subjects using the nearest flanking microsatellites (D16S301 and D16S496). We conducted an association study using black subjects with hypertensive end-stage renal disease, black normotensive control subjects, and black and white individuals from the general population. We used chi 2 analysis and Fisher's exact test to test for association with these candidate gene markers. No significant association was found between D16S301 and hypertension. However, a positive association with hypertension was found at the D16S496 microsatellite locus (chi 2 = 6.98, df = 1, P < or = .008). Our data suggest that HSD11B2 is associated with hypertension in our black subjects with hypertensive end-stage renal disease. The 16q22.1 chromosome region potentially harbors a candidate gene for essential hypertension. Confirmation of our findings in another independently ascertained group of hypertensive subjects will provide a basis for proceeding with sib-pair linkage analyses.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1995

Sedation for fibre optic bronchoscopy.

Most current sedative regimens for fibre optic bronchoscopy use an opioid, a benzodiazepine or a combination of both. This study compares midazolam (M) (a benzodiazepine), alfentanil (A) (an opioid) and a combination of both drugs (M+A). One hundred and three patients were randomized in double-blind manner into groups M(35), A(33) and M+A(35). The number of coughs, number of additional aliquots of lignocaine and duration of the procedures were recorded along with oxygen desaturation. The patient's level of discomfort was assessed by patient and bronchoscopist and expressed as a visual analogue score. There were significantly fewer coughs per minute in Group A compared with Group M (P = 0.0053), and significantly less lignocaine was required in Group A (P = 0.005) and in Groups M+A (P < 0.002) compared with Group M. There was no significant difference in the assessment of discomfort between the groups. There was a trend for Group M+A to desaturate more than the other two with a significant difference between desaturation in Group M+A and Group A (P = 0.033). Alfentanil is a more effective anti-tussive agent than midazolam for outpatient fibre optic bronchoscopy. The combination of alfentanil and midazolam does not provide any better anti-tussive effect and may have the risk of a greater degree of desaturation secondary to increased sedation.

Alfentanil↗
PubMed1995

Humoral and cell-mediated immune responses in healthy children after one or two doses of varicella vaccine.

This study compared the immune responses of healthy children to one or two doses of Oka/Merck varicella vaccine. Both cell-mediated and humoral immune responses were significantly stronger 1 year later among children given two doses 3 months apart than among those given a single dose. Long-term follow-up studies are needed to determine whether two doses of vaccine indeed provide more complete and more durable protection than a single dose against breakthrough varicella in healthy children.

Antibodies, Viral↗
PubMed1995

Saliva and serum as diagnostic media for antibody to hepatitis A virus in adults and in individuals who have received an inactivated hepatitis A vaccine.

Saliva was evaluated as a diagnostic fluid for screening individuals for evidence of previous hepatitis A virus (HAV) infection and for evidence of seroconversion after vaccination with inactivated hepatitis A vaccine. A new and simple saliva collection method and an assay for detection of HAV antibody were used; the assay used an antibody capture format. There was complete concordance between the results of saliva-based assays and those of serum-based assays, both of which were used for determining previous natural HAV exposure. However, for vaccine recipients, 100% concordance for saliva-based and serum-based assays occurred only at serum titers of > 9,000 mIU/mL, which were determined with use of the modified HAVAB assay. Saliva provides adequate sensitivity and specificity for determining naturally acquired HAV infection, although it is not useful in clinical trials for determining seroconversion after HAV vaccination.

Adult↗