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Biomedical subjects

D Hay

Publications and source records attributed to D Hay.

At least 37 records · Page 2Linked to original sources
PubMed1993

The rise and fall of smoking in New Zealand.

The prevalence of cigarette smoking in New Zealand has fallen over the past 20 years to 27% in both men and women. Rates remain high in women aged 15-24 years (33%) and in the Maori population (52% of men and women over 15 years). Tobacco consumption has fallen by 46% since 1975 and New Zealand now has the second lowest consumption of all OECD countries. Coincident with the reduction in smoking, there has been a 37% decline in age-standardised coronary heart disease mortality rates in men and 34% in women between 1968 and 1989. Since 1976 the incidence of lung cancer in men has fallen by 25% but increased by 38% in women. The decline was highest in non-Maori men aged 45-54 years (46%). Life expectancy has increased by four years in both men and women since 1970. New Zealand legislation against smoking was introduced in 1903 and culminated in the 1990 Smoke-free Environments Act. This provides for smoke-free environments, prohibition of tobacco advertising, restrictions on tobacco sponsorship, and the establishment of a Health Sponsorship Council.

Adolescent↗
PubMed1990

Union health centres.

Explore the source record for details and available documents.

Ambulatory Care Facilities↗
PubMed1988

Local recurrence of papillary thyroid carcinoma after unilateral or bilateral thyroidectomy.

Because prospective, randomized studies on papillary carcinoma of the thyroid are lacking, the results of retrospective studies from the basis of our present knowledge. To assess differences in treatment modalities, the patient groups must be comparable. A prognostic score has been devised by the use of multivariate analysis which can accurately distinguish patients at various levels of risk for disease-related mortality. To obtain the score, the calculated contributions of four significant variables are added. These variables are Age, tumor Grade, Extent, and Size (AGES). Using this scoring system, locally recurrent papillary thyroid carcinoma was studied in 816 patients primarily treated at the Mayo Clinic between 1946 and 1970. Locally recurrent disease developed in 54 (6.6%) patients, with the highest risk of occurrence in the first five years following initial thyroidectomy. Both in low- and high-risk patients, patients who had undergone unilateral thyroid resection had significantly more local recurrences than those with bilateral resections. However, there was no such difference when comparing subtotal to total thyroidectomy. Even though local disease was the cause of death in over one-half of the patients who died of thyroid cancer, this represented less than two percent of the entire series. From analysis of these data, bilateral resection - but not necessarily total thyroidectomy - with specific care to preserve both recurrent laryngeal nerves and at least one parathyroid gland in situ, seems to provide optimal treatment. When recurrence does occur, it appears worthwhile to attempt further surgical resection.

Adolescent↗
PubMed1986

Transmission of feline leukaemia virus in the milk of a non-viraemic cat.

The possibility of the transmission of feline leukaemia virus (FeLV) from latently infected cats was studied. Five female cats with latent infections were examined for evidence of transmission of the virus to their kittens. One of the cats infected members of four consecutive litters of kittens which subsequently became persistently viraemic and transmitted the virus to other susceptible kittens by contact. Shortly after birth its kittens were apparently FeLV-free since neither viral antigen nor infectious virus was detected in their blood and no virus was found in cell cultures made from aspirates of bone marrow. The kittens became viraemic from 45 days of age onwards at a time when their passively acquired colostral FeLV neutralising antibodies were no longer detectable. Transmission of the virus occurred via the milk since both FeLV antigen and infectious virus were found in milk samples taken six weeks after kittening and the virus was transmitted to a fostered kitten. Eleven weeks after the birth of the fourth litter the cat became viraemic. The intermittent presence of FeLV antigens detected by the Leukassay F test, but not infectious virus, in the plasma of this cat over the previous months and a low level of serum neutralising antibodies distinguished it from four other latently infected queens which did not transmit infection to their kittens. These factors may indicate a risk of milk transmission and reactivation of latent virus.

Animals↗
PubMed1986

The effect of age, gender, and sexual maturation on the caffeine breath test.

This study demonstrated the feasibility of utilizing the (3-13C-methyl) caffeine breath test (CBT) in children and adolescents, and examined the effect of gender, age, and puberty on the CBT. The CBT, expressed as the 2-hour accumulative exhalation of labeled CO2 (2-hour CO2), was compared to the CBT results in the adult. The 2-hour CO2 values were higher in the children than the adult, and the decrease in the CO2 values occurred in males during late puberty and in females during early puberty.

Adolescent↗
PubMed1985

The luteal phase after hyperstimulation for in vitro fertilization.

Of 500 cycles in which in vitro fertilization (IVF) was undertaken, laparoscopy was performed 372 times, 272 embryo transfers were carried out, and 55 pregnancies resulted, 30 of which resulted in delivery. Of those patients who underwent laparoscopy, 156 received clomiphene citrate alone, 203 clomiphene citrate and hMG, and 13 hMG alone. All patients were found to have a luteal-phase length of 10 days or greater (measured from the time of ovulation). The midluteal urinary total estrogen (UTE) value and pregnanediol excretion (Pd2) far exceeded the levels seen in normal cycles. There were no significant differences between conceptual and nonconceptual cycles and the high levels encountered would be expected after deliberate hyperstimulation. Fifty-five patients (in whom 11 pregnancies resulted) were monitored every other day throughout the luteal phase after embryo transfer. Both conceptual and nonceptual cycles showed a peak in pregnanediol glucuronide level around luteal day 6, which then fell. The level rose again if the corpus luteum was "rescued" by the implanting embryo. While the difference was not statistically significant, the estradiol levels appeared to decrease earlier in the nonconceptual cycles than in the continuing pregnancy cycles. It is important to note that the pattern of steroid production in the follicular phase was similar in both conceptual and nonconceptual cycles. While these data are not conclusive, they suggest that some nonconceptual cycles may have suffered early corpus luteal regression. Whether luteal-phase support is indicated in patients treated with clomiphene or clomiphene/hMG therapy cannot be determined from this study. However, it is thought that a controlled study of luteal-phase support in patients so stimulated is warranted. It appears that patients treated with hMG alone tend to undergo a compressed cycle and should be given luteal-phase support since other studies have reported shortened luteal phases following such hMG therapy.

Chorionic Gonadotropin↗
PubMed1984

Prediction of reading disability in twin boys.

Thirty-six twin boys aged between nine and 13 were assessed for intelligence and reading disability. Records of their birth status, early language development and social demographic characteristics were also available. 72 per cent of the sample had an accuracy reading age below their chronological age, and 59 per cent had a comprehension reading age below their chronological age, despite above-normal IQ. The best predictor of reading disability was preschool language status, accounting for 33 per cent of the variance in accuracy reading age discrepancy, and 23 per cent in comprehension reading age discrepancy in regression equations. This study shows that male twins are at very high risk for reading disability, and also offers support for the claim that language disability is basic to the development of reading problems.

Achievement↗
PubMed1982

Effect of dipyridamole on prostaglandin generation by human platelets and vessel walls.

These experiments were conducted to determine the effects of dipyridamole on human platelet aggregation, platelet thromboxane A2 (TXA2) and human vessel wall prostacyclin (PGI2) generation. Dipyridamole in varying concentrations (5 to 50 micrograms/ml) had no direct effect on ADP-induced platelet aggregation in vitro, but it potentiated PGI2-induced platelet aggregation inhibition at these concentrations. Dipyridamole also inhibited arachidonic acid-induced platelet TXA2 generation at these concentrations. In continuously perfused umbilical vein segments, dipyridamole treatment resulted in stimulation of PGI2 release determined by bioassay and by measurement of its stable metabolite 6-keto-PGF1 alpha. Minimum concentration of dipyridamole causing PGI2 release was 50 micrograms/ml. These in vitro studies suggest that anti-thrombotic effects of dipyridamole in man are mediated mainly by potentiation of PGI2 activity and to some extent by TXA2 suppression. Stimulation of PGI2 release by human vessels may not be seen in usual therapeutic concentrations.

Arachidonic Acid↗
PubMed1982

Thromboxane and prostacyclin generation by intact human vessels in response to balloon catheter trauma.

Recent description of thromboxane (TXA2) synthesis by endothelial cells in addition to prostacyclin (PGI2) has stimulated interest in the significance of TXA2 generation by vessel walls. We studied TXA2 and PGI2 release from human umbilical veins with intact and continuous endothelium. Resting TXB2 (stable metabolite of TXA2) concentrations in umbilical vein effluent (mean 0.45 +/- 0.07 ng/ml) were lower than those of 6-keto-PGF1 alpha (stable metabolite of PGI2) (mean 92 +/- 26 ng/ml). Following mechanical trauma to the umbilical veins with a balloon catheter, documented by adherence of indium111-labeled platelets, both TXA2 and PGI2 increased in the venous effluent. Increase in TXB2 (65%) was less than that in 6-keto-PGF1 alpha (199%). These data show that a) human vessel walls generate both TXA2 and PGI2, b) both TXA2 and PGI2 increase following mechanical trauma, the former less than the latter. Vessel wall TXA2 generation may become pathologically relevant in conditions of decreased PGI2 generation.

6-Ketoprostaglandin F1 alpha↗