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Biomedical subjects

L Giles

Publications and source records attributed to L Giles.

At least 19 recordsLinked to original sources
PubMed2002

Australian Longitudinal Study of Ageing: prospective evaluation of anthropometric indices in terms of four year mortality in community-living older adults.

The Australian Longitudinal Study of Ageing (ALSA) aims to identify factors that contribute to & predict the health & social well-being of older Australians. Analyses were performed to determine the predictive value of anthropometric measurements in older Australians for four-year mortality. Weight, height, skinfolds (triceps, abdominal, supra-spinale, sub-scapular, medial calf, and front thigh) & girth (arm, waist, hip, calf) measurements were performed on a randomly selected community-living sample of 772 men & 624 women aged>70 years. Waist: Hip, % weight loss, corrected-arm-muscle area (CAMA) & BMI were calculated. These measures were categorised into quartiles & also according to commonly adopted definitions of nutritional status. Cox regression analysis was undertaken to assess the predictive value of the independent anthropometric variables for four-year mortality, adjusting for potential confounders (age, gender, marital status, smoking, alcohol status, self-rated health, basic activities of daily living & co-morbidity). Risk of four-year mortality increased with weight loss >10% over two years (HR=2.53, CI=1.37-4.67) & CAMA <21.4cm2(M) & <21.6cm2(F) (HR=1.93, CI=1.03-3.60) independent of confounding variables. These results confirm that selected anthropometric indices (weight loss, CAMA) independently increase the risk of four-year mortality & highlights their potential use in the nutrition screening and assessment of community-living older adults.

Aged↗
PubMed1999

Ideals in intimate relationships.

This research examined lay relationship and partner ideals in romantic relationships from both a social-cognitive and an evolutionary perspective. Studies 1 and 2 revealed that the qualities of an ideal partner were represented by 3 factors (partner warmth-trustworthiness, vitality-attractiveness, and status-resources), whereas the qualities of an ideal relationship were represented by 2 factors (relationship intimacy-loyalty and passion). A confirmatory factor analysis in Study 3 replicated these factor structures but found considerable overlap across the partner and relationship dimensions. Studies 4 and 5 produced convergent and discriminant validity evidence for all 5 factors. Study 6 indicated that the higher the consistency between the ideals and related assessments of the current partner and relationship, the more positively the current relationship was evaluated.

Adolescent↗
PubMed1999

The effect of growth and measurement temperature on the activity of the alternative respiratory pathway

A postulated role of the CN-resistant alternative respiratory pathway in plants is the maintenance of mitochondrial electron transport at low temperatures that would otherwise inhibit the main phosphorylating pathway and prevent the formation of toxic reactive oxygen species. This role is supported by the observation that alternative oxidase protein levels often increase when plants are subjected to growth at low temperatures. We used oxygen isotope fractionation to measure the distribution of electrons between the main and alternative pathways in mung bean (Vigna radiata) and soybean (Glycine max) following growth at low temperature. The amount of alternative oxidase protein in mung bean grown at 19 degrees C increased over 2-fold in both hypocotyls and leaves compared with plants grown at 28 degrees C but was unchanged in soybean cotyledons grown at 14 degrees C compared with plants grown at 28 degrees C. When the short-term response of tissue respiration was measured over the temperature range of 35 degrees C to 9 degrees C, decreases in the activities of both main and alternative pathway respiration were observed regardless of the growth temperature, and the relative partitioning of electrons to the alternative pathway generally decreased as the temperature was lowered. However, cold-grown mung bean plants that up-regulated the level of alternative oxidase protein maintained a greater electron partitioning to the alternative oxidase when measured at temperatures below 19 degrees C supporting a role for the alternative pathway in response to low temperatures in mung bean. This response was not observed in soybean cotyledons, in which high levels of alternative pathway activity were seen at both high and low temperatures.

Journal Article↗
PubMed1998

Yearly colonoscopy, liver CT, and chest radiography do not influence 5-year survival of colorectal cancer patients.

BACKGROUND & AIMS: Guidelines on the type and frequency of follow-up of patients after curative surgery for colorectal cancer are unclear. The aim of this study was to determine the survival benefit of a planned follow-up program. METHODS: Three hundred twenty-five patients who underwent curative resection of colorectal cancer were prospectively randomized to either intensive or standard follow-up. After stratification according to Dukes' stage and site in the colon or rectum, patients were randomized to intensive follow-up of yearly colonoscopy, computerized tomography (CT) of the liver, and chest radiography and clinical review and simple screening vs. structured clinical review and simple screening tests only. RESULTS: On completion of 5-year follow-up, there was no significant difference in survival between the two groups. Yearly colonoscopy failed to detect any asymptomatic local recurrences. Only one asymptomatic curable metachronous colon tumor was detected. Liver CT resulted in earlier detection of hepatic metastases but did not increase the number of curative hepatectomies. Only 1 patient had an asymptomatic CT-detected liver metastasis, and another had an asymptomatic chest radiography-detected lung metastasis. Both had curative resections. CONCLUSIONS: Yearly colonoscopy, liver CT, and chest radiography will not improve survival from colorectal cancer when added to symptom and simple screening review.

Adult↗
PubMed1996

Sample size effects on temporal reliability of language sample measures of preschool children.

The present study examined the temporal reliability of four quantitative measurements of operationally defined linguistic behaviors observed in a naturalistic setting. The measures of language production were computed using the Systematic Analysis of Language Transcripts (SALT) software from two 20-minute language samples obtained 3 to 14 days apart for each of 20 preschool-aged children. Samples were edited to different sizes based either on duration (12 or 20 minutes) or on limits of the total number of complete and intelligible utterances (from 25 to 175 in increments of 25). Inadequate reliability was found for the language sample measure, total number of words; hence, the validity of this measure is questionable. In contrast, very high temporal reliability coefficients (r > .92) were obtained for the language sample measures of number of different words, mean length of utterance in morphemes, and mean sentence length in morphemes when derived from a large number (> or = 175) of complete and intelligible utterances. The temporal reliability of these measures reached acceptable levels, not only for research purposes, but for diagnostic purposes as well.

Child, Preschool↗
PubMed1996

Prevalence of blindness and visual impairment in an elderly urban population.

BACKGROUND: Accurate data on the prevalence of blindness in urban populations is not readily available. The Australian Longitudinal Study of Ageing is a prospective multidimensional study examining a broad range of age-related health issues, including visual function. METHODS: A population-based sample of 1466 persons, 70 years of age and over, from the Adelaide metropolitan area underwent visual acuity measurement. RESULTS: Approximately 1% were legally blind by Australian definitions. CONCLUSIONS: This percentage is low by world standards, however projections indicate that the absolute number of blind elderly people is rapidly increasing. Data such as this are crucial for the planning of adequate ophthalmic care.

Age Distribution↗
PubMed1994

Variations in plasma zinc in older men and women.

The study evaluated the biological and analytical variance in plasma zinc from 36 adults 60-88 yr of age. Blood samples were taken by finger-prick from each subject on d 1, 2, 3, 8, and 15. Days 1, 2, and 3 were selected to describe daily variation; 1, 8, and 15 were selected to describe weekly variation. Plasma Zn was analyzed by flame atomic absorption using a microinjection technique. Variation was partitioned into analytical, intraindividual, and interindividual components using analysis of variance. The interindividual variability was generally greater than the intraindividual variability. The variability for plasma zinc was about 30% and was substantially greater than reported for younger populations. This variability could not be attributed to the covariates examined, including zinc intake from food and supplements, serum albumin, and C-reactive protein. The variability would affect the accuracy of plasma zinc status based on a blood sample collected on a single day. With the microtechnique used in this study, 8 sample days would be needed to estimate plasma Zn with 95% confidence level and 20% level of accuracy.

Age Factors↗
PubMed1992

Measurements of the Engagement of Cyanide-Resistant Respiration in the Crassulacean Acid Metabolism Plant Kalanchoë daigremontiana with the Use of On-Line Oxygen Isotope Discrimination.

Discrimination against (18)O during dark respiration in tissues of Kalanchoë daigremontiana, Medicago sativa, and Glycine max was measured using an on-line system that enabled direct measurements of the oxygen fractionation of samples in a gas-phase leaf disk electrode unit. Discrimination factors for cytochrome pathway respiration were 18.6 to 19.8%(o) for all tissues. However, discrimination in cyanide-resistant respiration was significantly higher in green tissues (30.4-31.2%(o)) compared with nongreen tissues (25.3-25.9%(o)). Using these discrimination factors, the partitioning of electron transport to these pathways was calculated from measurements of discrimination in the absence of inhibitors. Changes in flux through the alternative pathway were measured during the light and dark phases of Crassulacean acid metabolism in leaf disks of K. daigremontiana. The flux of electrons through the alternative pathway was higher during deacidification than during the other phases of Crassulacean acid metabolism. The increase in alternative pathway electron flux accounted for all of the increased respiration in the light phase. Despite this increase, simultaneous measurements of malate concentration and respiratory flux confirm that only a small proportion of the total malate decarboxylation occurs in the mitochondria.

Journal Article↗
PubMed1991

Autotrophy in maize husk leaves : evaluation using natural abundance of stable isotopes.

The natural abundance of carbon and hydrogen isotopic composition, expressed as a delta(13)C value of plant dry matter and cellulose in the hypsophylls (husk leaves) of maize (Zea mays L.) was measured and compared with that of leaves and cobs. The delta(13)C values of outer hypsophylls were usually 2 to 3% per thousand more negative than leaves or other tissues, and became more negative with increasing chlorophyll content, indicating significant local C(3) pathway fixation of CO(2) in the outer hypsophylls. The deltaD values indicated a significant part of hypsophyll cellulose was derived from heterotrophic sources (sucrose from C(4) photosynthesis in other tissues). Isotopic mass balance calculations allowed quantitative estimation of these carbon sources and, in the samples examined, about 16% of hypsophyll cellulose was derived from local C(3) photosynthesis, about 62% from local C(4) photosynthesis, and about 22% from sucrose imported from other leaves.

Journal Article↗
PubMed1989

Chorionic villus sampling: diagnostic uses and limitations of enzyme assays.

Control ranges for enzymes in uncultured chorionic villi were established, based on: (1) 21 of 22 enzymes (mainly lysosomal) in villi had similar properties to the enzyme in cultured fibroblasts; (2) isoenzyme patterns in villi were similar to those in fibroblasts for five lysosomal enzymes but different for aryl sulphatases; (3) control ranges were determined for 12 enzymes in abortion villi and for 21 enzymes in biopsy villi, values tending to be higher in the latter for those enzymes studied in both types of sample; (4) storage of samples under various conditions revealed no major changes in activity of seven lysosomal enzymes. A number of potential pitfalls in the use of chorionic villus samples for diagnosis of metabolic disorders by enzyme assay are described: (1) the presence of aryl sulphatase C in chorionic villi, an isoenzyme which may interfere in assays of aryl sulphatase A; (2) the presence of maternal enzyme in chorionic villus material illustrated by the detection of the A isoenzyme of B-hexosaminidase in chorionic villus from a pregnancy affected with Sandhoff's disease; (3) the finding of falsely normal levels of alpha-iduronidase in chorionic villus samples from a pregnancy affected with Hurler's disease, probably due to contamination with maternal tissue which has relatively high levels of this enzyme compared with fetal chorionic material: (4) the inadequacy of indirect assays of incorporation of radiolabel into macromolecules using chorionic villi, for example [14C]propionate incorporation for prenatal diagnosis of methylmalonic aciduria. Provided that such pitfalls are recognized and great care is taken in selection of villus samples and interpretation of results, chorionic villus sampling allows reliable prenatal diagnosis of a large number of disorders using enzyme assays.

Chorionic Villi Sampling↗
PubMed1988

First trimester prenatal diagnosis of Sandhoff's disease.

Chorionic villus sampling was performed on two patients with a previous family history of Sandhoff's disease. Total beta-hexosaminidase (Hex) activity in case 1 was within the normal range (case 1: 6365 mumol/h/g protein; control range: 3227-24 495 mumol/h/g protein). The beta-hexosaminidase isoenzyme pattern was found to be normal. These results were confirmed on cultured amniotic fluid cells. In case 2, the total Hex activity was 672 mumol/h/g protein, i.e., 7 per cent of the control mean (10,085 mumol/h/g protein), and chromatography demonstrated that more than 50 per cent of this activity was due to the abnormal isoenzyme beta-hexosaminidase S (Hex S). The fetus was predicted to be affected by Sandhoff's disease and this was confirmed on fetal tissues after termination of pregnancy. This study demonstrates that a fetus affected by Sandhoff's disease can be reliably diagnosed during the first trimester of pregnancy.

Adult↗
PubMed1988

First trimester diagnosis of methylmalonic aciduria.

We have studied methylmalonyl CoA mutase activity in control chorionic villi to establish the potential use of assays performed directly on this tissue for prenatal diagnosis of methylmalonic aciduria. We report the detection of a fetus affected with the apo-mutase deficient form of this condition at 9 weeks' gestation. Methylmalonyl CoA mutase was markedly deficient in chorionic villi, approximately 2.5 per cent of the mean control value. However, incorporation of label from [14C]-propionate into protein was 10 and 40 per cent of the mean control value, respectively, in two portions of the same biopsy, highlighting potential problems in the use of this indirect assay. Normal results were obtained in chorionic villus samples from four other pregnancies 'at risk' for methylmalonic aciduria which were subsequently shown to be unaffected with this condition. The diagnosis in the affected pregnancy was confirmed by demonstration of a marked deficiency of methylmalonyl CoA mutase activity in villi obtained at termination and in cultured fetal fibroblasts. Reduced incorporation of [14C]-propionate label into protein was also found in these tissues.

Amino Acid Metabolism, Inborn Errors↗
PubMed1987

Clinic experience of prenatal diagnosis of cystic fibrosis by use of linked DNA probes.

96 families at risk of having a child with cystic fibrosis have been counselled about prenatal diagnosis by the use of linked DNA probes. Of the first 30 pregnancies 9 children have been born and confirmed to be free from CF, as predicted; 8 pregnancies were terminated (1 of these was found to be miscarrying at time of termination); 12 pregnancies, in which the fetuses are predicted to be unaffected, are in progress; and 1 has miscarried. No couple with a prenatal prediction of CF decided to continue with the pregnancy. 1 pregnancy was terminated because of a 50:50 chance of an affected fetus. In 1 twin pregnancy the affected fetus was selectively aborted, and the other baby was confirmed after birth to be unaffected, as predicted. In the other twin pregnancy the two chorionic plates could not be samples separately; the pregnancy was continued on the basis of normal findings for the lower plate, and both twins have turned out to be normal. Many couples at risk see early prenatal diagnosis as a way to help them have an unaffected child.

Abortion, Induced↗
PubMed1987

Aryl sulphatase isoenzymes of chorionic villi: implications for prenatal diagnosis.

Prenatal diagnosis of metachromatic leucodystrophy (MLD) is based on demonstrating a deficiency of aryl sulphatase A (ASA) in the fetus. To evaluate the place of chorionic villus sampling for prenatal diagnosis of this condition, the properties of ASA were compared in chorionic villi and cultured skin fibroblasts. Considerable differences with respect to pH optimum, Km values and linearity with incubation time were found. These differences can be explained by the presence of aryl sulphatase C (ASC), a major component in chorionic villi and placenta. This isoenzyme was shown to have activity towards p-nitrocatechol sulphate (NCS) thereby interfering in the colorimetric assay most often used to detect MLD (Baum et al., 1959)

Cerebroside-Sulfatase↗
PubMed1987

Krabbe's disease: first trimester diagnosis confirmed on cultured amniotic fluid cells and fetal tissues.

Chorionic villi obtained during the first trimester from a pregnancy at risk for Krabbe's disease were shown to have reduced cerebroside-beta-galactosidase (E.C.3.2.1.46) activity using the artificial substrate trinitrophenylaminolauryl galactocerebroside (TNPAL-galactocerebroside). Assay of this enzyme in cultured amniotic fluid cells following amniocentesis, performed at the patient's request confirmed the diagnosis. Termination of pregnancy was performed and subsequent enzyme studies of the fetal tissues were consistent with the diagnosis of Krabbe's disease, thus confirming that chorionic villi can be used for first trimester diagnosis of this condition.

Amniocentesis↗
PubMed1980

The reliability of a Survey Psychiatric Assessment Schedule for the elderly.

The Survey Psychiatric Assessment Schedule (SPAS) was used in a survey of elderly people living at home and in institutions to examine its reliability in determining mental state. A psychiatrist assessed the same subjects using the Geriatric Mental State Schedule (GMSS) and classified psychiatric disorder into three broad groups: organic disorders, schizophrenia and paranoid disorders, and affective disorders and psychoneuroses. The agreement between the psychiatrist's classification of mental state and the classification derived from SPAS was found to be satisfactory for organic disorders and less satisfactory for functional disorders. The limitations of this method of identifying psychiatric illness are examined.

Aged↗
PubMedDate not supplied

Evaluation of a partnership model of care delivery involving registered nurses and unlicensed assistive personnel.

The employment of unlicensed personnel in Canadian acute care hospitals has been undertaken without clear evidence of outcomes for patients, caregivers, and hospital organizations. This quasi-experimental evaluation study was completed in a metropolitan Toronto acute care hospital to examine the effects of a new nursing care delivery system which included unlicensed assistive personnel. Most of the expected benefits of the newly implemented nursing care delivery system did not materialize leading to the conclusion that the employment of unlicensed assistive personnel in acute care hospital systems may not offer additional benefits for patients, caregivers, or hospital organizations. The processes and results of this study provide useful information for nurse administrators who are seeking effective and innovative care delivery systems that are designed to optimize patient, caregiver, and hospital outcomes.

Attitude of Health Personnel↗