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Biomedical subjects

A W Taylor

Publications and source records attributed to A W Taylor.

At least 37 records · Page 2Linked to original sources
PubMed2000

Mental health status of the South Australian population.

OBJECTIVE: To determine, by the use of a telephone survey, the mental health status of SA adults (18+ years) using the GHQ-28, SF-12 and self-report as indicators of mental health, and to examine risk factors for mental health morbidity. SAMPLE: A random representative sample of South Australian adults selected from the Electronic White Pages. Overall, 2,501 interviews were conducted (74.0% response rate). RESULTS: Overall, 19.5% of respondents had a mental health problem as determined by the GHQ-28, 11.8% as determined by the mental health component summary score of the SF-12 and 11.9% self-reported a mental health condition. The percentage of people with a mental health problem who had used a psychologist or a psychiatrist in the previous 12 months was 9.6% for people diagnosed by the GHQ-28, 16.2% by SF-12 and 23.7% for self-report. The logistic regression analyses undertaken to describe people with a mental health problem as determined by the GHQ-28 and to describe people who visited a psychologist or psychiatrist produced different age categories, demographic and co-morbidity indicators. Variables found in both analyses included living in the metropolitan area, being economically inactive and being a high user of health services. CONCLUSIONS: One in five South Australian adults has a mental problem. Although the prevalence is higher for younger age groups, older adults are more likely to visit a psychologist or a psychiatrist. IMPLICATIONS: Telephone interviewing produces robust indicators of the prevalence of mental health problems and is a cost-effective way of identifying prevalence estimates or tracking changes over time.

Adolescent↗
PubMed2000

The prevalence of pelvic floor disorders and their relationship to gender, age, parity and mode of delivery.

OBJECTIVE: To define the prevalence of pelvic floor disorders in a non-institutionalised community and to determine the relationship to gender, age, parity and mode of delivery. DESIGN: A representative population survey using the 1998 South Australian Health Omnibus Survey. SAMPLE: Random selection of 4400 households; 3010 interviews were conducted in the respondents' homes by trained female interviewers. This cross sectional survey included men and women aged 15-97 years. RESULTS: The prevalence of all types of self-reported urinary incontinence in men was 4.4% and in women was 35.3% (P<0.001). Urinary incontinence was more commonly reported in nulliparous women than men and increased after pregnancy according to parity and age. The highest prevalence (51.9%) was reported in women aged 70-74 years. The prevalence of flatus and faecal incontinence was 6.8% and 2.3% in men and 10.9% and 3.5% in women, respectively. Pregnancy (> 20 weeks), regardless of the mode of delivery, greatly increased the prevalence of major pelvic floor dysfunction, defined as any type of incontinence, symptoms of prolapse or previous pelvic floor surgery. Multivariate logistic regression showed that, compared with nulliparity, pelvic floor dysfunction was significantly associated with caesarean section (OR 2.5, 95% CI 1.5-4.3), spontaneous vaginal delivery (OR 3.4, 95% CI 2.4-4.9) and at least one instrumental delivery (OR 4.3, 95% CI 2.8-6.6). The difference between caesarean and instrumental delivery was significant (P<0.03) but was not for caesarean and spontaneous delivery. Other associations with pelvic floor morbidity were age, body mass index, coughing, osteoporosis, arthritis and reduced quality of life scores. Symptoms of haemorrhoids also increased with age and parity and were reported in 19.9% of men and 30.2% of women. CONCLUSION: Pelvic floor disorders are very common and are strongly associated with female gender, ageing, pregnancy, parity and instrumental delivery. Caesarean delivery is not associated with a significant reduction in long term pelvic floor morbidity compared with spontaneous vaginal delivery.

Adolescent↗
PubMed2000

Neuropeptide regulation of immunity. The immunosuppressive activity of alpha-melanocyte-stimulating hormone (alpha-MSH).

The ocular microenvironment is an extreme example of regional immunity. Within its microenvironment, expression of delayed type hypersensitivity (DTH) is suppressed. This immunosuppression is mediated in part by the constitutive expression of alpha-MSH. Previously we have found that alpha-MSH suppresses the production of IFN-gamma by activated effector T cells. Recently we have found that alpha-MSH can mediate induction of TGF-beta-producing T cells that act as regulatory T cells. This has encouraged us to further examine the potential for alpha-MSH to suppress T cell-mediated inflammation (autoimmune disease) and to regulate lymphokine production by effector T cells. When alpha-MSH was injected i.v. into mice at the time of peak retinal inflammation, the severity of experimental autoimmune uveitis (EAU) was significantly suppressed. Effector T cells activated in vitro in the presence of alpha-MSH proliferated and produced IL-4 and enhanced levels of TGF-beta while their IFN-gamma and IL-10 production was suppressed. The alpha-MSH-treated T cells functioned as regulatory T cells by suppressing in vitro IFN-gamma production by other inflammatory T cells. This regulatory activity was the function of alpha-MSH-treated CD4+ CD25+ T cells. Therefore, alpha-MSH mediates immunosuppression by inducing a differential expression of lymphokine production and by inducing activation of regulatory functions in T cells. This implies that alpha-MSH may take part in regional mechanisms of immunosuppression and possibly peripheral tolerance. Thus, alpha-MSH can be used to suppress autoimmune disease and possibly reestablish tolerance to autoantigens.

Animals↗
PubMed2000

Neural control of ocular immune privilege.

Ocular immune privilege arises from interactions between the immune apparatus and the eye itself, thereby providing immune protection for the eye that is devoid of sight-threatening inflammation. On the one hand, antigens injected intraocularly elicit deviant systemic immune responses that are devoid of immunogenic inflammation (Anterior Chamber-Associated Immune Deviation, ACAID). On the other hand, the ocular microenvironment (aqueous humor, secreted by cells that surround this chamber) suppresses intraocular expression of immunogenic inflammation. Several lines of evidence indicate that ocular immune privilege is under neural control. First, aqueous humor contains neuropeptides (alpha-MSH, VIP, CGRP) that inhibit and alter the functional properties of T lymphocytes and macrophages. Second, when corneal nerves are severed, the tissues surrounding the anterior chamber cease secreting immunosuppressive factors and ACAID fails--until the nerves regrow. Third, light deprivation abolishes the capacity of the anterior chamber to support ACAID induction, a process that is sensitive to neuropeptides and melatonin. The photoreceptor(s) responsible for ACAID are connected to the nervous system and may reside in the anterior segment and/or the retina. Thus, neural elements from the central nervous system and within the eye help to shape both the induction and the expression of ocular immunity, thereby promoting immune privilege.

Animals↗
PubMed2000

Muscle metabolism during heavy-intensity exercise after acute acetazolamide administration.

Carbonic anhydrase (CA) inhibition is associated with a lower plasma lactate concentration ([La(-)](pl)), but the mechanism for this association is not known. The effect of CA inhibition on muscle high-energy phosphates [ATP and phosphocreatine (PCr)], lactate ([La(-)](m)), and glycogen was examined in seven men [28 +/- 3 (SE) yr] during cycling exercise under control (Con) and acute CA inhibition with acetazolamide (Acz; 10 mg/kg body wt iv). Subjects performed 6-min step transitions in work rate from 0 W to a work rate corresponding to approximately 50% of the difference between the O(2) uptake at the ventilatory threshold and peak O(2) uptake. Muscle biopsies were taken from the vastus lateralis at rest, at 30 min postinfusion, at end exercise (EE), and at 5 and 30 min postexercise. Arterialized venous blood was sampled from a dorsal hand vein and analyzed for [La(-)](pl). ATP was unchanged from rest values; no difference between Con and Acz was observed. The fall in PCr from rest [72 +/- 3 and 73 +/- 3.6 (SE) mmol/kg dry wt for Con and Acz, respectively] to EE (51 +/- 4 and 46 +/- 5 mmol/kg dry wt for Con and Acz, respectively) was similar in Con and Acz. At EE, glycogen (mmol glucosyl units/kg dry wt) decreased to similar values in Con and Acz (307 +/- 16 and 300 +/- 19, respectively). At EE, no difference was observed in [La(-)](m) between conditions (46 +/- 6 and 43 +/- 5 mmol/kg dry wt for Con and Acz, respectively). EE [La(-)](pl) was higher during Con than during Acz (11.4 +/- 1.0 vs. 8.2 +/- 0.6 mmol/l). The similar [La(-)](m) but lower [La(-)](pl) suggests that the uptake of La(-) by other tissues is enhanced after CA inhibition.

Acetazolamide↗
PubMed2000

IL-6 antagonizes TGF-beta and abolishes immune privilege in eyes with endotoxin-induced uveitis.

PURPOSE: To determine the immunosuppressive status of aqueous humor (AqH) from mouse eyes afflicted with endotoxin-induced uveitis (EIU) and to identify the relevant cytokines responsible for immunomodulatory activity within EIU AqH. METHODS: Bacterial lipopolysaccharide (LPS) was injected into hind footpads of C3H/HeN mice; and AqH, collected at 6, 12, 24, and 48 hours, was evaluated for content of transforming growth factor (TGF)-beta, tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, and interferon (IFN)-gamma and capacity to suppress anti-CD3-driven T-cell proliferation. Cytokine mRNA expression in iris-ciliary body (I/CB) was analyzed by RNase protection assays. RESULTS: During 6 to 24 hours after LPS injection, total TGF-beta levels in AqH increased even though the fluid lost its capacity to suppress T-cell activation. At this time, AqH contained high levels of IL-6, and I/CB contained high levels of IL-6 mRNA. When IL-6 was neutralized with specific antibodies, inflamed AqH reacquired its capacity to suppress T-cell activation, which correlated with high levels of TGF-beta. Coinjection of IL-6 plus antigen into the anterior chamber of the eye of normal mice prevented antigen-specific anterior chamber-associated immune deviation (ACAID). CONCLUSIONS: LPS-induced intraocular inflammation is associated with local production of IL-6, which robs AqH of its immunosuppressive activity, perhaps by antagonizing TGF-beta. The fact that IL-6 antagonized ACAID induction in normal eyes suggests that strategies to suppress the intraocular synthesis of IL-6 may reduce inflammation and restore ocular immune privilege.

Animals↗
PubMed2000

A decade of aerobic endurance training: histological evidence for fibre type transformation.

BACKGROUND: Researchers employing a variety of training methods have demonstrated a fast-to-slow fibre transformation in animal skeletal muscle. The observation as to whether this occurs in exercise trained humans is limited and equivocal. METHODS EXPERIMENTAL DESIGN: to examine this issue, skeletal muscle from seven subjects who had participated in a decade or more of high intensity aerobic training (DT) and six nontrained (NT) subjects was obtained by muscle biopsy from the vastus lateralis muscle (VL) and subjected to a modified myofibrillar ATPase technique to identify muscle fibre types. Muscle tissue was histochemically treated by exposure to an alkaline preincubation (pH 9.9), an acid preincubation (pH 4.3 or 4.6) and the formate-KCI preincubation buffer (pH 4.54), previously employed in animal studies. RESULTS: The formate-KCl preincubation medium identified all major fibre types at a single pH in human subjects. The percentage of type I fibres in DT was 70.9% vs 37.7% in NT (p<0.01), while the type IIa fibres in DT (25.3%) was much lower (p<0.01) than NT (51.8%). Surprisingly, type IIa fibres in the DT group displayed lesser oxidative staining intensity (p<0.01) than type IIa fibres from the NT group. Mean cross-sectional area of type I fibres for DT (6233.9+/-1421.7 microm2) was greater (p<0.05) than either type I (5746.8+/-1135.2 microm2) or II (5693.5+/-1214.6 microm2) from NT. CONCLUSIONS: The results revealed that endurance training may promote a transition from type II to type I muscle fibre types and occurs at the expense of the type II fibre population.

Adenosine Triphosphatases↗
PubMed2000

Comparison of fructose and glucose ingestion before and during endurance cycling to exhaustion.

BACKGROUND: Pre-exercise and exercise ingestion of fructose and glucose during cycling exercise were compared. METHODS EXPERIMENTAL DESIGN: Seventeen trained subjects ingested a placebo prior to and during a cycling test to exhaustion at 75% VO2max (control group = CG). One week later, subjects were matched on exercise time to exhaustion (ETE) and assigned to a fructose group (FG) or a glucose group (GG). Subjects then performed a second cycling test to exhaustion, ingesting fructose or glucose doses. For all groups (CG, FG and GG), blood was drawn before and at timed intervals during exercise to determine glucose, lactate and free fatty acid (FFA) levels. RESULTS: The ETE for CG was less than either FG (p<0.02) or GG (p<0.001) but FG and GG were similar. FG and GG did not show any differences in blood lactate or blood FFA during the ETE. However, CG FFA levels were higher than those of FG (p<0.02) prior to exercise. CONCLUSIONS: This study demonstrated that fructose and glucose are of equal value in prolonging ETE in endurance cycling Ingesting fructose before and during exercise apparently provided a more constant supply of glucose to be available to the working muscles. The more stable blood glucose levels with fructose ingestion may be beneficial in reducing perceived exhaustion, and thereby allowing for an enhancement in exercise performance.

Adult↗
PubMed1999

Hormone replacement therapies in women at risk of cardiovascular disease and osteoporosis in South Australia in 1997.

OBJECTIVE: To describe changes in use of hormone replacement therapy (HRT) in an Australian population and to determine HRT use in women at risk of cardiovascular disease and osteoporotic fracture. DESIGN: Data were derived from the 1997 South Australian Health Omnibus Survey (a representative population survey) and compared with data from 1991, 1993 and 1995 Omnibus Surveys. SETTING: South Australia, 1997. PARTICIPANTS: 1049 women aged 40 years and over from a random selection of 4400 households. RESULTS: Among women aged 55-64 years (and thus likely to be postmenopausal), 60% had used HRT (ever use). Nearly two-thirds of these women used it currently. In this age group, mean length of HRT use had increased to 70 months (median, 60 months). Rates of HRT use had not changed significantly between 1991 and 1997 in women under 55 years, but had increased significantly in women aged 55 years or over (P < or = 0.01). Among women currently using HRT, 5.4% had used testosterone therapy, while 4% used unregistered products purported to contain hormones. Rates of ever use of HRT in women with zero, one, two, or three or more cardiovascular risk factors were 33%, 37%, and 45%, respectively. Among women with a diagnosis of osteoporosis, 52% had used HRT, with a mean length of use of 86 months (median, 60 months). CONCLUSION: HRT use is increasing in older-age groups. Longer-term therapy with potential for primary prevention is now occurring, but half of those with osteoporosis and more than half of those with risk factors for cardiovascular disease have not used HRT.

Adult↗
PubMed1999

Mice with Th2-biased immune systems accept orthotopic corneal allografts placed in "high risk" eyes.

CD4+ T cells of the Th1 type play a central role in acute rejection of solid tissue grafts, including orthotopic corneal allografts. Th1 cells, which mediate delayed hypersensitivity, are the polar opposites of CD4+ Th2 cells, and the latter cells cross-regulate Th1 cells through the unique pattern of cytokines they secrete. As such, Th2 cells may have a useful role to play in preventing rejection of corneal allografts. To test this possibility, the immune systems of adult mice were biased toward Th2 responses by immunization with keyhole limpet hemocyanin plus IFA. When immunized subsequently with either OVA or allogeneic corneal tissue, these mice acquired Ag-specific primed T cells of the Th2 type. More important, allogeneic corneas grafted into neovascularized eyes of Th2-biased mice experienced significantly enhanced survival. To demonstrate that enhanced survival was promoted by donor-specific Th2 cells, lymphoid cells from keyhole limpet hemocyanin-immune mice bearing healthy corneal allografts suppressed orthotopic corneal allograft rejection when adoptively transferred into naive, syngeneic recipients. We conclude that acceptance of corneal allografts in neovascularized mouse eyes can be significantly enhanced by biasing the recipient immune system toward Th2 responses.

Adoptive Transfer↗
PubMed1999

Quantitative analysis of xanthohumol and related prenylflavonoids in hops and beer by liquid chromatography-tandem mass spectrometry.

A method for quantitation of six prenylflavonoids (xanthohumol, isoxanthohumol, desmethylxanthohumol, 6- and 8-prenylnaringenins and 6-geranylnaringenin) in hops and beer by HPLC-tandem mass spectrometry has been developed. The method allows direct analysis of beer and crude methanolic extracts of hops. After HPLC separation, prenylflavonoids were detected by positive ion multiple-reaction monitoring using a triple-quadrupole mass spectrometer equipped with a heated nebulizer--atmospheric pressure chemical ionization interface. The accuracy and precision were evaluated by replicate analyses of (spiked) samples. Thirteen commercial beers were analysed with the method. Isoxanthohumol, formed by isomerization of xanthohumol during the brewing process, was the most abundant flavonoid in hopped beers, ranging from 0.04 to 3.44 mg/l.

Beer↗
PubMed1999

Fate of xanthohumol and related prenylflavonoids from hops to beer.

The fate of three prenylated flavonoids of the chalcone type, xanthohumol, desmethylxanthohumol, and 3'-geranylchalconaringenin, was monitored with LC/MS-MS from hops (Humulus lupulus L.) to beer in two brewing trials. The three prenylchalcones were largely converted into their isomeric flavanones, isoxanthohumol, prenylnaringenins, and geranylnaringenins, respectively, in the boiling wort. Losses of prenylflavonoids were due to incomplete extraction from the hops into the wort (13-25%), adsorption to insoluble malt proteins (18-26%), and adsorption to yeast cells (11-32%) during fermentation. The overall yield of xanthohumol, after lagering of the beer and largely in the form of isoxanthohumol, amounted to 22-30% of the hops' xanthohumol. About 10% of the hops' desmethylxanthohumol, completely converted into prenylnaringenins, remained in the beers. 3'-Geranylchalconaringenin behaved similarly to desmethylxanthohumol. Solubility experiments indicated that (1) malt carbohydrates form soluble complexes with xanthohumol and isoxanthohumol and (2) solubility does not dictate the isoxanthohumol levels of finished beers.

Beer↗
PubMed1999

The epidemiology of hearing impairment in an Australian adult population.

BACKGROUND: This study measured the prevalence of hearing impairment, and major demographic factors that influence the prevalence, in a representative South Australian adult population sample aged > or = 15 years. METHODS: The study group was recruited from representative population surveys of South Australians. Participants in these surveys who reported a hearing disability were then recruited to an audiological study which measured air and bone conduction thresholds. In addition a sample of those people who reported no hearing disability were recruited to the audiological study. RESULTS: The data reported in this study are the first in Australia to assess the prevalence of hearing impairment from a representative population survey using audiological methods. The data show that 16.6% of the South Australian population have a hearing impairment in the better ear at > or = 25 dBHTL and 22.2% in the worse ear at the same level. The results obtained in this representative sample compare well with those obtained in the British Study of Hearing, although some differences were observed. CONCLUSIONS: Overall, there are only a few studies worldwide that have audiologically assessed the impairment of hearing from a representative population sample. The overall prevalence of hearing impairment in Australia is similar to that found in Great Britain, although there are some differences between the estimates of severity of impairment and some sex differences. The corroboration of the two studies reinforces the status of hearing impairment as the most common disability of adulthood. The present study also showed that there are a large number of Australians who may benefit from a more systematic community-based rehabilitation programme including the fitting of hearing aids. Secondly, the study identified the need for health goals and targets for hearing to be based on an epidemiological approach to the problem.

Adolescent↗
PubMed1999

Reliability of self-reported behavioural health risk factors in a South Australian telephone survey.

OBJECTIVE: To test the reliability of telephone health survey questions. METHOD: A telephone survey on mental health of South Australians in 1997 was re-administered to a random sub-sample of 102 respondents between 32 and 79 days after the original survey. RESULTS: Demographic questions (age, gender, number of adults and children in the household) showed the highest reproducibility and were almost perfect. Questions regarding health risk factors, such as smoking and drinking behaviour, showed substantial to almost perfect agreement. Co-morbidity variables were substantially reproducible where prevalence estimates were not close to zero. CONCLUSIONS: The results were comparable to findings from similar studies associated with the Behavioral Risk Factor Surveillance System (BRFSS) in the United States. The study suggests that the telephone health survey instrument used in South Australia is reliable for estimating health conditions and behaviours in the population.

Adolescent↗
PubMed1999

Random digit dialling and Electronic White Pages samples compared: demographic profiles and health estimates.

OBJECTIVE: To compare the methodologies of and health estimates derived from two telephone household survey methods. In particular, to establish if White Pages telephone listings provide a relatively unbiased sampling frame for population health surveys. METHOD: In South Australia in 1998, a health survey questionnaire was administered by telephone to two randomly selected population samples. The first method used EWP (Electronic White Pages, n = 6,012), which contains all listed residential telephone numbers as the sampling frame. The results were compared to a RDD (random digit dialling, n = 3,080) sample where all listed and unlisted telephone numbers were included in the sampling frame. Demographic variables and health estimates were compared between the surveys, and then compared to a 'gold standard' door-to-door household survey conducted concurrently. RESULTS: The response rate for EWP (83.8%) exceeded that of RDD (65.4%). More than four times as many calls were required per completed interview in RDD. Demographic profiles and health estimates were substantially similar. CONCLUSIONS: EWP requires fewer telephone calls and enables approach letters establishing the bona fides of the survey to be sent to each selected address before calling, increasing the response rate. RDD is a more inclusive sampling frame but also includes non-connected and business numbers, and offers no significant advantages in providing health estimates. IMPLICATIONS: There are substantial methodological and cost advantages in using EWP over RDD as the sampling, frame for population health surveys, without introducing significant bias into health estimates.

Adolescent↗
PubMed1999

Transforming growth factor beta isoforms in human optic nerve heads.

AIM: To determine if the isoforms of transforming growth factor beta (TGF-beta) are present in fetal, normal adult, and glaucomatous optic nerve heads. METHODS: To localise cells synthesising TGF-beta, optic nerve heads were stained using antibodies to TGF-beta 1, TGF-beta 2, and TGF-beta 3. To demonstrate synthesis, human optic nerve heads from fetal, glaucomatous, and normal age matched subjects were explanted, cultured overnight, and the culture supernatant was assayed for the presence of TGF-beta 1 and TGF-beta 2 by bioassay. In addition, semiquantitative RT-PCR was performed to determine the gene expression pattern of TGF-beta 2. RESULTS: Immunohistochemistry of glaucomatous samples revealed the presence of intense staining for TGF-beta 2 primarily in astrocytes, whereas TGF-beta 1 was localised to blood vessels. No TGF-beta 3 immunoreactivity was observed. There was little or no expression of TGF-beta in normal optic nerve heads. Optic nerve heads from glaucomatous eyes released 70-100-fold more TGF-beta 2 than normal age matched optic nerve heads. Fetal optic nerve heads released 90-100-fold more TGF-beta 2 than normal adult optic nerve heads. TGF-beta 1 was undetectable by bioassay in all samples tested. There was no apparent increase in TGF-beta 2 gene expression in glaucomatous and fetal eyes, suggesting post-transcriptional regulatory mechanisms. CONCLUSIONS: These results demonstrate that TGF-beta 2 is produced in high levels in the fetal and glaucomatous optic nerve heads, perhaps by a mechanism of post-transcriptional regulation. TGF-beta may be important during development of the optic nerve head and, in glaucoma, TGF-beta 2 may be a mediator of astrocyte reactivation and extracellular matrix remodelling in the lamina cribrosa.

Aged↗
PubMed1999

The effects of endurance training on muscle fibre types and enzyme activities.

Practitioners and scientists have demonstrated great interest in the physiological and biochemical effects of endurance training on the results of the marathon run. It is well documented that athletes with a large proportion of slow twitch and fast twitch aerobic skeletal muscle fibre, high metabolic enzyme activities and concentrations, large mitochondria concentration and, of course, the ability to increase the power output generated for a given rate of oxygen consumption and energy expenditure, are generally highly successful distance runners. Aerobic and endurance training have been shown to bring about significant adaptations to the skeletal muscle and its inclusions as well as to the delivery system. In particular, enzyme activity levels are readily mutable, mitochondrial concentrations increase, and some evidence suggests that the fibre distribution is changed. This article briefly reports on changes in skeletal muscle brought about by endurance training and those changes that appear most effective in yielding success in endurance events.

Energy Metabolism↗