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Biomedical subjects

R A Shaw

Publications and source records attributed to R A Shaw.

At least 37 records · Page 2Linked to original sources
PubMed1994

Conformational changes in the cyclic undecapeptide cyclosporin induced by interaction with metal ions. An FTIR study.

Infra-red spectra have been measured for the cyclic undecapeptide cyclosporin A (CsA) and three analogues CsC, CsD and CsH in acetonitrile and in the presence of 10:1 molar excess of Mg2+, Ca2+, Na+ or Li+ in the same solvent. Interaction with each of these ions is suggested by marked changes in band positions over the amide I region (1600-1700 cm-1). The formation of complexes of cyclosporin with calcium and magnesium ions is indicated by the presence of C = O stretching bands well outside the range normally expected for the amide I absorptions of free peptides. Although they share this characteristic, the spectra indicate that the mode and/or strength of Ca2+ binding is quite different from that of Mg2+ binding. In contrast, the two monovalent ions interact with CsA, CsC and CsD to yield spectra that are very similar to one another. The spectra are consistent with binding of the monovalent ions simultaneously to several carbonyl groups of the loop structure.

Acetonitriles↗
PubMed1992

The use of a videotaped questionnaire for studying asthma prevalence. A pilot study among New Zealand adolescents.

OBJECTIVE: To examine the feasibility of measuring asthma prevalence by means of an audio-visual presentation of asthma symptoms and signs (video questionnaire) and to compare this technique with a standard written questionnaire for predicting bronchial hyperresponsiveness. DESIGN: A cross-sectional study comparing the ability of a video questionnaire and a written, interviewer administered questionnaire to predict bronchial hyperresponsiveness. Bronchial responsiveness was measured with hand held nebulisers. SETTING: Community survey of a New Zealand rural secondary school. SUBJECTS: A total of 456 adolescent school children aged 12-19 years (mean 15.5 years). OUTCOME MEASURES: Comparison of the sensitivity and specificity of a standard questionnaire versus a video questionnaire for bronchial hyperresponsiveness. RESULTS: The technique was easy to administer in the community setting. Overall sensitivity and specificity for the prediction of bronchial hyperresponsiveness were similar for the video and interviewer administered questionnaires. CONCLUSIONS: This new technique is easily used in the community setting, and gives predictions of bronchial hyperresponsiveness similar to those of a standard interviewer administered questionnaire. Further examination of the technique in comparisons of asthma prevalence among different populations is planned.

Adolescent↗
PubMed1992

Comparison of a video questionnaire with the IUATLD written questionnaire for measuring asthma prevalence.

A video questionnaire (VQ) for measuring asthma prevalence in adolescents was assessed for repeatability and validity in relation to bronchial hyperresponsiveness (BHR) (PD20 less than or equal to 7.8 mumol methacholine). Comparison was also made with a standard, self completed written questionnaire (SQ), based on the IUATLD Bronchial Symptoms Questionnaire, which included five questions seeking comparable data to those in the VQ. Both the VQ and SQ were administered to 707 schoolchildren (13-16 years), in whom English was the primary language. One hundred and six randomly selected children subsequently underwent bronchial challenge to methacholine. Both the sensitivity and specificity for BHR were higher for a combination of three or more positive responses to the VQ (0.73 and 0.88), than to the SQ (0.63 and 0.82), although these differences were not statistically significant (P = 0.24). When administered again after a two week interval, the VQ had a significantly higher (P = 0.03) coefficient of repeatability (0.79) than the SQ (0.50). We conclude that the VQ is a valid and reliable method of determining asthma prevalence, and propose that by providing data relatively free from biases due to language, culture, literacy or interviewing techniques it may be particularly useful when comparing asthma prevalence and severity in different populations.

Adolescent↗
PubMed1991

Asthma symptoms, bronchial hyperresponsiveness and atopy in a Maori and European adolescent population.

In 1989 a survey of 543 New Zealand rural adolescents of largely Maori descent was undertaken to determine the prevalence of asthma symptoms, bronchial hyperresponsiveness (BHR) and atopy. The overall prevalence of asthma was estimated at 13.7%, BHR at 13.4% and atopy at 31.1%. These rates were similar across the age range 13 to 18 years. The prevalence of BHR among those without asthma symptoms was 3%. Both current asthma symptoms and BHR were more common among females, but there was no difference between the sexes in the proportion with atopy. The prevalence of asthma symptoms was higher among Maoris than nonMaoris, but this difference disappeared when allowance was made for current smoking. There was a similar prevalence of BHR and atopy between these two ethnic groups. There was a similar prevalence of asthma but lower prevalence of BHR than was reported among 7-10 year olds in an urban Auckland survey. The low prevalence of BHR among those without asthma symptoms, and the uniform frequency of asthma symptoms, BHR and atopy over the age range suggest that adolescents would be a particularly useful population for national or international comparisons of the prevalence of asthma, BHR and atopy.

Adolescent↗
PubMed1991

The changes in smoking habits in a rural adolescent population, 1975-89.

A survey of tobacco smoking habits in 435 adolescent schoolchildren was undertaken in 1989 in a rural, largely Maori population. The survey questionnaire was identical to that used in a 1975 survey at the same school. Among this group, Maori still smoke more often than nonMaori (36.6% vs 25.2%), and currently this is particularly true for females (46.7% vs 31.3%). Among currently smoking Maori, both in males and females cigarette consumption has significantly risen (median per week: 15 vs 30), despite an overall fall in the proportion of the groups who report smoking within the previous month (57.1% vs 36.6%). As a result, there are now significantly more smokers in the highest consumption group than previously (7.0% vs 12.6%), particularly among Maori females (7.5% vs 16%). Similar but lesser trends have occurred among nonMaori, with the exception that in addition to cigarette consumption, the proportion of females currently smoking has also tended to rise. There remains considerable cause for concern about smoking among this younger age group.

Adolescent↗
PubMed1990

Progesterone levels on the day of human chorionic gonadotropin administration in cycles with gonadotropin-releasing hormone agonist suppression are not predictive of pregnancy outcome.

In in vitro fertilization (IVF) cycles using gonadotropin-releasing hormone agonist (GnRH-a) suppression, we investigated whether an elevated progesterone (P) level on the day of human chorionic gonadotropin (hCG) administration indicates premature luteinization and is associated with a lower pregnancy rate. We retrospectively studied 101 patients treated with the GnRH-a leuprolide acetate, begun in the luteal phase of the prior menstrual cycle and continued until the day of hCG administration. On the day of hCG, 72 patients had P less than 0.9 ng/mL and 29 had less than or equal to 0.9 ng/mL. Patients in the high P group had a significantly greater estradiol level on the day of hCG. No significant difference in clinical pregnancy rates or ongoing pregnancy rates occurred between the low P and high P groups. We conclude that in IVF cycles pretreated with GnRH-a, P levels on the day of hCG are not predictive of conceiving in that cycle.

Adult↗
PubMed1990

Increasing asthma prevalence in a rural New Zealand adolescent population: 1975-89.

A survey of asthma symptoms and spirometry in 435 adolescent schoolchildren was undertaken in 1989 in a rural, largely Maori population. The survey questionnaires were identical to those used in a 1975 survey at the same school. The prevalence of reported asthma or wheeze significantly increased from 26.2% to 34.0%. This increase occurred in groups reporting asthma, and also those reporting wheeze unassociated with colds, but without a previous diagnosis of asthma. There was a tendency for a rise in reported wheeze in Europeans (24.3% to 27.4%) and a significant rise in Maoris (27.1% to 36.2%). The reclassification of other respiratory problems did not account for the increase. Data from this study provides evidence that there has been a rise in the prevalence of asthma in this New Zealand population over a time period of 14 years.

Adolescent↗
PubMed1990

Intravenous pulsed steroids in rheumatoid arthritis: a comparative dose study.

This prospective, double blind study was undertaken to test the efficacy of intravenous "minipulse" (100 mg) methylprednisolone (MP) therapy versus standard pulse (1000 mg) MP therapy in rheumatoid arthritis (RA). Thirty-six patients with RA synovitis flares were randomized to receive either 100 or 1000 mg MP IV QD x 3 doses. These 2 universally comparable groups exhibited no statistically significant differences in their striking prompt and sustained clinical improvement. These data suggest that minipulse MP is as efficacious as conventional pulse MP in the treatment of RA flares.

Adult↗
PubMed1985

Comparison of intravenous and oral routes of theophylline loading in acute asthma.

In a prospective, randomized clinical trial, 19 patients with an acute exacerbation of asthma were given a loading dose of aminophylline by the IV (n = 10) or oral route (n = 9) of administration following treatment with epinephrine. Plasma concentrations of theophylline were measured prior to giving the loading dose, and one, two, three, and 24 to 48 hours later. Therapeutic effectiveness was evaluated by analyzing spirometric measurements prior to giving the loading dose, and one, three, and 24 to 48 hours later. Side effects also were recorded. In the IV group, the mean peak plasma theophylline concentration was 15.1 micrograms/mL one hour after loading, and in the oral group the mean peak serum theophylline concentration was 14.2 micrograms/mL three hours after loading. There was no correlation between theophylline concentrations and normalized change in spirometric values. There was no significant difference in spirometric values between the IV and oral groups. Nausea was slightly more common in the IV group. We conclude that there is no therapeutic advantage to giving a loading dose of aminophylline by the IV route rather than orally in patients with mild-to-moderate exacerbation of asthma initially treated with epinephrine.

Acute Disease↗
PubMed1984

Life Saver: a complete team approach incorporated into a hospital-based program.

Both military and civilian settings have shown that a team approach through an excellent prehospital Emergency Medical Services system, an organized regional communication system, access to rapid air evacuation with a "complete" medical team on board, and dedicated trauma resources allows a critically ill or injured patient optimal chances for survival. The Life Saver airborne emergency service, operated by Carraway Methodist Medical Center in Birmingham, Alabama, is a "complete team" concept with a well trained emergency physician and a critical care flight nurse aboard every flight. The physician upgrades the level of care at the scene of an accident, lessens the referring physician's anxiety, maintains an intensive care unit environment during transport and intervenes if a life threatening emergency occurs, which cannot be predicted prior to lift-off. This report describes the development, operations, and results in the aeromedical transport of 1047 patients from January 2, 1981 to December 31, 1982. Trauma transports accounted for 47.5%, nonsurgical problems 47.8% and nontraumatic surgical patients representing the remaining 4.7%. The in-flight mortality was 0%. This type service is not appropriate for all hospitals to provide, but should be considered by major trauma and cardiac referral centers.

Adolescent↗
PubMed1982

Progressive and transient hypoxic ventilatory drive tests in healthy subjects.

In order to ascertain the correlation between progressive and transient hypoxic ventilatory drive tests, 18 healthy subjects were tested by both methods, and the results were compared. Sudden cessation of steady-state hypoxia was done in 9 of the subjects to determine if an exaggerated central depressant effect of hypoxia might occur in some persons during progressive testing and explain a low response to progressive hypoxia. Because the progressive hypoxia test is frequently used in evaluating the effects of therapeutic interventions on ventilatory drive, the reproducibility of this test over time was also evaluated in 10 subjects. THere was a significant correlation between the results of the progressive and transient hypoxic tests when data from 17 of the 18 subjects were compared by linear regression analysis (r = 0.56, p less than 0.05). In 1 of 18 subjects, the ventilatory response to progressive hypoxia was quite low, whereas the response to transient hypoxia was high, and this can possibly be explained by an exaggerated central depressant effect of hypoxia. The progressive hypoxia test is quite reproducible (variance = 0.0092) over a 5- to 7-month period. We conclude that the use of progressive or transient hypoxic ventilatory drive tests will result in similar conclusions regarding the hypoxic ventilatory drive in most persons. In addition, the progressive hypoxia test can be reliably used to evaluate the effects of therapeutic interventions on hypoxic ventilatory drive.

Adult↗