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Biomedical subjects

R Jackson

Publications and source records attributed to R Jackson.

At least 307 records · Page 17Linked to original sources
PubMed1990

The effect of oxytocin infusion on adenohypophyseal function in man.

The responses of the adenohypophyseal hormones adrenocorticotrophin (ACTH), growth hormone (GH), thyroid stimulating hormone (TSH), prolactin, luteinizing hormone (LH) and follicle stimulating hormone (FSH) to sub-maximal doses of hypothalamic releasing factors were studied in six lean male volunteers (age 23-35 years) with and without infusions of oxytocin (OXT). OXT infusion (mean plasma concentration 133.6 +/- 2.6 pmol/l) completely inhibited the plasma ACTH responses to corticotrophin releasing hormone (CRH) (saline, peak increment ACTH 1.61 +/- 0.75 pmol/l; OXT, peak increment ACTH - 0.04 +/- 0.28 pmol/l; P less than 0.05). OXT infusion had no significant effect on the GH response to growth hormone releasing hormone (GHRH), the TSH and prolactin responses to thyrotrophin releasing hormone (thyroliberin, TRH) or the LH and FSH responses to gonadotrophin releasing hormone (luteoliberin, GnRH). The data support a role for OXT in the modulation of ACTH secretion in man.

Adrenocorticotropic Hormone↗
PubMed1990

Hormonal studies on women with polycystic ovaries diagnosed by ultrasound.

Eighty-six patients were diagnosed by ultrasound to have polycystic ovaries. Twelve have fairly regular but anovular cycles (P1), 56 had oligomenorrhoea (P2) and eight had primary or secondary amenorrhoea (P3). The remaining 10 patients had raised progesterone concentrations and were excluded from the hormonal studies. Gonadotrophins, steroid hormones and sex hormone binding globulin (SHBG) were measured in all patients and the results were compared with those of 29 normal women who acted as controls. A high LH:FSH ratio was the most frequently found abnormality (raised in 68.4% of patients) followed by LH (65.8%), free testosterone (FT, calculated from total testosterone (T) and SHBG) (59.2%) and 17-OHP (48.7%). Each of these four estimations was above the normal ranges in 25% of patients: proportionally most of the results outside the normal range occurred in group P3 followed by P2 and P1 respectively. To obtain a quantitative measure of the abnormalities, results were expressed as percentages of the mean control value for each hormone and these percentages were then summated. The four measurements, LH:FSH ratio, LH, FT and 17-OHP gave abnormality scores ranging from a mean of 667 in P1 to 1189 in P3 compared with 405 in controls. Twenty-one of the 76 patients were hirsute with significantly higher androgens than the nonhirsute patients. Their mean abnormality score was 1141 compared with 855 in the non-hirsute group and they all had at least one hormonal abnormality. The study demonstrates that there is a relationship between the degree of hormonal abnormality and the menstrual irregularities and hirsutism in women with PCOS suggesting that there may be a progressive nature to the syndrome.

17-alpha-Hydroxyprogesterone↗
PubMed1990

Immunoalkaline phosphatase technique applied to paraffin wax embedded tissues in diagnostic renal pathology.

An indirect immunoalkaline phosphatase (IAP) technique was used to evaluate the glomerular deposition of immunoglobulins, C3, C1q and fibrinogen. In 80 renal biopsy specimens the results obtained using this technique were compared with those obtained by direct immunofluorescence to see if it could be used as a viable alternative. The IAP technique was straightforward to perform, it yielded quick results, and was highly reproducible, provided that a standardised short fixation period of two and a half hours was used. For the detection of immunoglobulin deposits, the IAP results correlated well with those of immunofluorescence. Despite poorer performance in identifying complement components and fibrinogen it could, within certain limits, provide an adequate diagnostic alternative to immunofluorescence. Each technique gave false negative results, those of immunofluorescence being related to its failure to identify mesangial deposition of IgA in two cases where its distribution seemed to be focal, and those of IAP to a failure to detect linear deposition of IgG in all three cases of anti-glomerular basement membrane disease.

Alkaline Phosphatase↗
PubMed1990

Cold subcutaneous abscesses.

Cold abscesses are defined as having no associated erythema, heat, or tenderness. They may be present in immunodeficiency disorders, deep mycoses, and other infectious diseases. As there is a dearth information on this subject in the dermatology, surgery, and infectious disease literature, we present a case of cold abscesses secondary to coccidioidomycosis and discuss the possible role of humoral immunity, cell-mediated immunity, prostaglandins, T cells, and other mediators in cold abscess pathogenesis. In addition, therapeutic guidelines for abscesses are reviewed.

Abscess↗
PubMed1989

Changes in plasma vitamin levels in the first 48 hours after onset of acute myocardial infarction.

To establish whether plasma vitamin measurements made after acute myocardial infarction (AMI) can be used in case-control studies of coronary artery disease, the short-term effect of AMI on plasma concentrations of 25-hydroxyvitamin D3, beta-carotene, vitamin E and retinol was investigated. Sequential measures of these vitamins were made during the first 48 hours after AMI in 13 patients admitted to the hospital within 4 hours after the onset of symptoms. Plasma levels of 25-hydroxyvitamin D did not change significantly during the first 12 hours after onset of symptoms. Beta-carotene levels increased significantly (p less than 0.05) during the first 12 hours and then decreased, whereas levels of vitamin E and retinol progressively decreased during the first 48 hours by 26 and 25%, respectively. These results suggest that, of these vitamins, only plasma measurements of 25-hydroxyvitamin D3 collected within 12 hours of onset of symptoms may provide reliable information for case-control studies of AMI.

Aged↗
PubMed1989

Trends in antihypertensive medication costs in a cohort of Aucklanders 1982-87.

This study examines the trends in drug treatment and costs of hypertension in a cohort of 1600 adult Aucklanders between 1982 and 1987. In 1987 prices the average daily cost of antihypertensive drug treatment per person increased from 42 cents to 74 cents over the five year period. The increase in cost seen in antihypertensive therapy in this cohort is explained by the introduction of new and more expensive drugs rather than by increases in the proportion of the population being treated for hypertension, daily dosage, number of antihypertensives per individual or in real prices of antihypertensives.

Adult↗
PubMed1989

Patterns in the drug treatment of hypertension in Auckland, 1982-7.

This paper examines the pattern of drug treatment of hypertension in Auckland in the period 1982 to 1987 using data from a representative sample of the adult population interviewed in 1982 and followed up in 1987. In 1982 the age standardised prevalence of antihypertensive treatment for people aged 40-64 years was 12.2% (95%Cl 10.4, 14.0) and in 1987 it was 10.2% (95%Cl 8.5, 11.8). Over the five year period of this study, 6% of the sample untreated in 1982 began treatment with antihypertensive medication, while 24% of those on drugs in 1982 had stopped treatment by 1987. The most common medications used in both 1982 and 1987 for hypertension were diuretics and beta blockers. Over the five year period diuretic use fell and beta blocker use remained constant. In 1982 3% of hypertensives were taking a calcium antagonist but in 1987 13% were on these drugs and a further 13% were using ACE inhibitors. This study suggests that the prevalence of drug treatment for hypertension has plateaued in New Zealand; coincidentally there is a trend towards use of more expensive drugs.

Adult↗
PubMed1989

Prescribed fenoterol and death from asthma in New Zealand, 1981-83: case-control study.

A case-control study was conducted to examine the hypothesis that fenoterol by metered dose inhaler (MDI) increases the risk of death in patients with asthma. The case group comprised 117 patients aged 5-45 who died of asthma between August, 1981, and July, 1983. For each case, 4 controls, matched for age and ethnic group, were selected from asthma admissions to hospitals to which the cases themselves would have been admitted, had they survived. The relative risk of asthma death in patients prescribed fenoterol by MDI was 1.55 (95% CI 1.04-2.33, p = 0.03). The possibility of confounding or effect modification by severity was assessed by consideration of subgroups defined by markers of asthma severity. The fenoterol MDI relative risk was 2.21 (95% CI 1.26-3.88, p = 0.01) in patients prescribed three or more categories of asthma drugs, 2.16 (95% CI 1.14-4.11, p = 0.02) in patients with a hospital admission for asthma during the previous 12 months, and 6.45 (95% CI 2.72-15.3, p less than 0.01) in patients prescribed oral corticosteroids at time of death or admission. In the group of patients with the most severe asthma (defined by a hospital admission during the previous year and prescription of oral corticosteroids) the fenoterol MDI relative risk was 13.29 (95% CI 3.45-51.2, p less than 0.01). After adjustment for severity, no other asthma treatment commonly used in New Zealand seemed to be associated with an increased risk of asthma death. Not all sources of bias can be definitely excluded; however, when considered together with other epidemiological and experimental evidence, these findings are consistent with the hypothesis that use of fenoterol by MDI increases the risk of death in severe asthma.

Acute Disease↗
PubMed1989

The validity of Maori mortality statistics.

Data from an Auckland coronary heart disease register have been used to assess the validity of Maori mortality statistics produced by the National Health Statistics Centre. During the period 1983-4, 804 people aged 35-64 years and resident in the Auckland statistical region, were identified by both the register and death registration data as having died of coronary heart disease. The coronary heart disease register failed to classify the ethnicity of thirteen of these people. Of the remaining 791 cases, the register classified 80 as Maori while only 44 were classified as Maori in the national death registration data; over the period 1983-4 Maori mortality due to coronary heart disease in the Auckland statistical region was understated by 82% (80-44/44). Although some of this discrepancy may be due to differences in classification of ethnicity, the major reason for the understatement is missing information on the death registration form. Simple changes in the documentation of ethnicity could markedly reduce the degree of underreporting.

Adult↗
PubMed1989

Activity of the pyrazoloacridines against multidrug-resistant tumor cells.

A series of 2-aminoalkyl-5-nitropyrazolo [3,4,5-kl]acridines (pyrazoloacridines) were tested in vitro against a panel of multidrug-resistant cell lines comprising Adriamycin-resistant P388 leukemia, B16 melanoma, and mammary adenocarcinoma 16c. This new class of anticancer agents, particularly the 9-substituted methoxy derivatives, exhibited significant activity against all of the lines tested. The degree of cross-resistance to these compounds ranged from zero to 8-fold in the 138-fold Adriamycin-resistant P388/ADR line and was greatly diminished in the B16/ADR and 16c/ADR lines. Selected pyrazoloacridines were subsequently tested in vivo against B16 and B16/ADR cells established as solid tumors from the tissue culture line and shown to retain a significant degree of Adriamycin resistance. Whereas the B16/ADR line exhibited 2 logs less net tumor-cell kill than the B16 parent in response to Adriamycin treatment, the resistant tumor was completely sensitive to the pyrazoloacridines tested and proved in some experiments to be collaterally sensitive. The favorable activity of the pyrazoloacridines against these Adriamycin-resistant tumor lines points to the potential efficacy of these compounds against multidrug-resistant tumors encountered clinically.

Acridines↗
PubMed1989

Pharmacodynamics of a contraceptive vaginal ring releasing 3-keto-desogestrel.

The pharmacodynamic effects of a new type of 3-keto-Desogestrel [3kDOG] releasing vaginal ring was studied in a group of 20 normally ovulating women during a period of 21 days continuous use. Peripheral blood samples were taken for the estimation of progesterone and oestradiol levels, ultrasound tracking for follicular growth and cervical mucus sampling for scoring [modified Insler] and sperm penetration testing during a control, treatment and recovery period. Additional blood samples were taken for the estimation of 3kDOG levels during the treatment period. After a control cycle, twenty normally ovulating women were selected and randomly divided into two groups. Group A were given a vaginal ring on day 5 of the menstrual cycle releasing 30 ug/24 hours of 3kDOG and group B a similar ring releasing 15 ug/24 hours of kDOG. Of the treatment cycles, none showed an ovulatory pattern in group A and there was only one in group B, the respective mean plasma levels of 3kDOG were 0.38 and 0.25 pmol/ml. The formation of "cysts" or persistent follicles was common to both groups, 6 out of 10 subjects in group A and 8 out of 10 subjects in group B had "cysts" greater than 25mm in diameter in the treatment cycle, this had become 5 out of 10 and 8 out of 10, respectively, in the recovery cycle. A comparison of the cervical mucus scores and sperm penetration of cervical mucus showed a significant reduction between the control and treatment groups but no significant difference between the two groups. The bleeding profiles showed an increase in percentage of bleeding days in both treatment groups to 25% in group A and 21.7% in group B [cf, 17.1%, 15.9%, respectively, in control month]; there being no statistical difference between groups. In conclusion, it is believed that given the efficacy demonstrated and the low level of menstrual disturbances found, this system warrants further investigation as a means of contraception as it appears to offer a better compromise than previous vaginal ring systems.

Administration, Intravaginal↗
PubMed1989

The in vivo release characteristics of a multi-compartment vaginal ring releasing 3-keto-desogestrel.

The results of a stage I study of a new vaginal ring releasing 3-keto-Desogestrel [3kDOG] is reported. The study design consisted of one study cycle, where the ring was used continuously for 21 days and then removed. Twenty healthy volunteers were randomly allocated to each of two study groups. On day 5 of the menstrual cycle, group A used a vaginal ring releasing 30 micrograms 3kDOG per 24 hours and group B used a 15 micrograms 3kDOG per 24 hours ring. After initial absorption of the 3kDOG a plateau phase was reached in 46 hours [group A] and 49 hours [group B]. On reaching the plateau phase, the overall decline in plasma levels during the 21 days of use was 5.24% for group A and 5.27% for group B. This represents a daily decline in plasma levels of 0.27% and 0.28% for the 30 micrograms and 15 micrograms per 24 hours rings, respectively. The plasma levels achieved by the rings were significantly different throughout (p = 0.011). On removal after 21 days, the mean removal half-life for both ring types was similar at 20.9 hours for group A and 21.1 hours for group B. It is concluded that the characteristics of the delivery system are worthy of further study as a potential means of contraception using 3kDOG delivered from a vaginal ring.

Administration, Intravaginal↗
PubMed1989

Sleep-associated breathing disorders in morbidly obese children and adolescents.

Forty-one children and adolescents with a history of breathing difficulty during sleep and morbid obesity, defined as greater than 150% ideal body weight, underwent polysomnography to determine the incidence of sleep-associated breathing disorders. Seventeen patients also performed pulmonary function testing. The mean patient age was 10.3 +/- 4.4 (SD) years, and mean percent of ideal body weight was 208 +/- 42.2. A sleep history questionnaire showed that all patients snored, but frank apnea was reported in only 32%. The pulmonary function tests showed 18% (3/17) with a restrictive defect and 47% (8/17) with obstructive changes. The polysomnograms in 37% (15/41) of the patients were abnormal because of apnea, hypopnea, excessive arousals, or abnormalities in gas exchange. Multiple regression analysis demonstrated no significant association between weight, age, or gender and any physiologic measure on the polysomnogram. Most of the abnormal polysomnograms (13/15) were mildly abnormal, but two showed sufficiently severe abnormalities to require clinical intervention. We conclude that children and adolescents with morbid obesity are at risk for sleep-associated breathing disorders; their polysomnographic abnormalities are usually mild but rarely may be severe enough to require clinical intervention.

Adolescent↗
PubMed1989

The distribution of immunoreactive interferon-alpha in normal human tissues.

The cellular distribution of immunoreactive interferon-alpha (IFN-alpha) was studied in formalin-fixed paraffin-embedded normal human tissues from 36 different organs. These samples were drawn from over 300 individuals none of whom had evidence of viral infection. Tissue histiocytes from all organs in the body, with the exception of brain and renal cortex and medulla, stained positively for IFN-alpha. Kupffer cells, pulmonary alveolar macrophages and lymph node macrophages were also positive. Parenchymal cells in some other organs also appeared to contain immunoreactive IFN-alpha. These included cuboidal lining cells of the choroid plexus in the brain, thyroid follicular cells, pituitary endocrine cells, adrenocortical cells and parathyroid principal and oxyphil cells. These findings are compatible with previous suggestions that IFN-alpha may be synthesized and released in the absence of viral infection and may thus have a role in normal physiology. The presence of IFN-alpha in most cells of the mononuclear phagocyte system suggests that these cells may play a major part in defence against viral infection.

Endocrine Glands↗
PubMed1989

CHD in Australia and New Zealand.

Death rates from coronary heart disease (CHD) have been declining in Australia and New Zealand for 20 years. Data from the three MONICA Project Centres in Newcastle (Australia), Perth (Australia), and Auckland (New Zealand) show similar trends for fatal CHD but differing trends for non-fatal myocardial infarction (MI). In Auckland, there has been a consistent decline in out-of-hospital death rates but no decline in non-fatal MI rates. In Perth, the greater contribution to the overall decline has been from out-of-hospital deaths, but in-hospital death rates and non-fatal MI rates have also declined. There is also some evidence of an increase in survival following MI in Perth. In Newcastle, both death rates and non-fatal MI rates have declined. The limited data available suggest that at least one-half of the decline in mortality can be attributed to improvements in population risk-factor levels. Improvements in medical management of both risk factors and established disease are also making contributions to the decline.

Adult↗