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Biomedical subjects

J Halliday

Publications and source records attributed to J Halliday.

At least 37 records · Page 2Linked to original sources
PubMed1998

Preterm infants 30-36 weeks' gestation in Victoria--where should they be delivered?

There is little doubt that very preterm infants <30 weeks' gestation should be born in level-3 perinatal centres. For preterm infants 30-36 weeks' gestation, however, the optimum place of birth is not so clear-cut. The aims of this study of livebirths 30-36 weeks' gestational age born in Victoria were to determine: 1) the proportions delivered outside level-3 centres, and 2) for infants born outside level-3 centres, the proportions transferred after birth to a level-3 nursery in the first days after birth. Data on the number of livebirths 30-36 weeks' gestational age in Victoria in the 3 years 1994-1996, inclusive, were supplied by the Victorian Perinatal Data Collection Unit. Data were obtained from the Newborn Emergency Transport Service (NETS) on all transfers within the first 3 days after birth to a level-3 centre for infants born outside level-3 centres. For the 3 years 1994-1996 there were 11,375 livebirths 30-36 weeks' gestational age in Victoria. The proportion born outside a level-3 perinatal unit was 57.9% overall, and rose with increasing gestational age, from 10.9% at 30 weeks to 69.0% at 36 weeks. Of the 6,587 livebirths outside a level-3 centre, 808 (12.3%) were transferred within the first 3 days after birth by NETS to a level-3 centre, the proportions falling with increasing maturity, being 73.7%, 48.5%, 28.4%, 26.9%, 18.8%, 11.8%, and 7.0% at 30, 31, 32, 33, 34, 35, and 36 weeks, respectively. These data may help medical practitioners when determining the place of delivery for infants 30-36 weeks' gestation.

Delivery Rooms↗
PubMed1998

Smoking, obesity, and hypertension alter the dose-response curve and test sensitivity of carbohydrate-deficient transferrin as a marker of alcohol intake.

Serum carbohydrate-deficient transferrin (CDT) is a specific and comparatively sensitive marker of excessive alcohol use; however, reports of its sensitivity vary according to the population or patient groups studied and their average alcohol intake. We have characterized the dose-response curve between alcohol intake and CDT concentrations in a study of 1400 men and women from a community-based twin registry. Our results show that mean CDT increases with increasing reported alcohol consumption even within the range of alcohol use considered to be nonhazardous. We found significant effects of sex, age, smoking, previous alcohol dependence, body mass index, and diastolic hypertension on the alcohol-CDT dose-response curve. These variables either affect test sensitivity or require adjustment of reference intervals. The results also provide insight into the physiological and biochemical factors that affect CDT concentration.

Adult↗
PubMed1997

Use of record linkage between a statewide genetics service and a Birth Defects/Congenital Malformations Register to determine use of genetic counselling services.

The Birth Defects/Congenital Malformations Register of the Victorian Department of Human Services contains detailed, confidential information on over 2,000 babies born with a birth defect each year in Victoria, Australia, representing approximately 3% of the annual number of births. For 1991 and 1993, the type of anomaly was categorised as warranting a high, moderate, or low need of referral for genetic counselling, depending on risk of recurrence and possible genetic cause. The Victorian Clinical Genetics Service at the Murdoch Institute, Melbourne, offers free, centralised genetic counselling services for the entire state. A comparison of case records between the two agencies has shown little difference in overall use of genetic counselling between 1991 (17%) and 1993 (16%). Rate of uptake in the "high need" category improved only slightly during that period, from 40% in 1991 to 43% in 1993. Utilization of genetic counselling services did not vary disproportionately with mother's country of birth, but was higher for older mothers. As was expected, rates were highest when a baby was born at the only hospital that provides on-site genetic counselling services. Even where a statewide genetic counselling service is in place, it is disappointing that over half of those judged at high need for genetic counselling are not making use of this service. This study will provide baseline information to which future studies can be compared. Using the same study methodology, it will be possible to examine whether the uptake rate increases in accordance with increased genetic services.

Congenital Abnormalities↗
PubMed1997

Expression and localization of the retinoblastoma gene during radiation-induced apoptosis in neonatal rat kidney.

An in vivo neonatal rat kidney model was used to study an association between expression and localization of the retinoblastoma tumor-suppressor gene (Rb), or its protein product (pRb), and localization of radiation-induced apoptosis. The rat kidney has two distinct zones of differentiation at birth-an outer nephrogenic zone, in which cells are undifferentiated and new nephrons are forming, and a differentiated zone internal to this zone that has essentially the adult kidney form. At 6 h after radiation (5 Gy), high levels of relatively synchronous apoptosis are induced in the nephrogenic zone, with little effect on the differentiated zone, and proliferation in the nephrogenic zone is almost totally inhibited by radiation treatment, again with little effect in the differentiated area. We have used our knowledge of this model to analyze control (sham-treated) and irradiated renal tissue for Rb mRNA transcript levels and localization (Northern blot and in situ hybridization (ISH)), pRb expression (Western blot and immunolocalization), apoptosis and mitosis (light and electron microscopy, and DNA gel electrophoresis for apoptosis), and cells in S-phase ([3H]thymidine uptake and autoradiography). Northern blots showed no detectable alteration in Rb transcript levels between control and irradiated tissues, whereas Western blots indicated increased expression of pRb in protein extracted from irradiated kidney compared with controls. ISH confirmed that Rb transcripts were not substantially altered in the nephrogenic and differentiated zones in control versus irradiated renal tissue. Immunolocalization of pRb demonstrated little effect in the differentiated zone, but in the nephrogenic zone pRb expression was increased, especially the S-shaped prenephrons, and was also found in many, but not all, apoptotic cells in this zone. The results link radiation-induced apoptosis and increased pRb expression in a zone of the neonatal kidney having a low level of cell differentiation.

Animals↗
PubMed1996

Molecular cloning of a partial cDNA of a novel gene in iron metabolism.

In order to elucidate the possible role played by human hepatic ferritin-associated protein in normal cellular iron metabolism and in iron overload diseases, malignancies and hepatic fibrosis, we attempted to isolate genes for ferritin associated proteins. Here we describe the cloning of a novel cDNA fragment of a 10 kb mRNA transcript from human liver and human T lymphoid (MOLT-4) cells using a short degenerate 5'-primer derived from six amino acid residues of an affinity purified ferritin associated protein from human liver. Northern analysis of this clone has revealed the presence of a 10 kb mRNA species in both human liver and MOLT-4 cell RNA.

Amino Acid Sequence↗
PubMed1995

Comparison of women who do and do not have amniocentesis or chorionic villus sampling.

Even in areas where prenatal diagnostic testing is offered at no cost to women over a certain age, uptake of testing is not complete. We have studied the factors that affect uptake in Victoria, Australia. In 1988-92, 43% of 37-39-year-old women and 29% of those 40 years and over had no diagnostic testing despite their eligibility for a free test. We compared the characteristics of untested women (n = 3074) with those of tested women (2462 amniocentesis, 1575 chorionic villus sampling) by use of record-linkage between the Victorian birth register and fetal diagnosis data collection. The indication for testing was maternal age alone. Women who had had 3 or more previous births were less likely than those of lower parity to undergo testing (odds ratio 0.54 [95% CI 0.46-0.63], p < 0.001), whereas those who had had a previous termination of pregnancy were more likely to be tested than those who had not (1.52 [1.26-1.83], p < 0.001). Women born in non-English-speaking countries and women who lived in rural areas were less likely to be tested. Women who gave birth in private hospitals were more likely to be tested than those who gave birth in any public hospital or at home. These data help to distinguish between issues of choice and access to diagnostic testing. Factors that hinder testing of rural women and of those from non-English-speaking backgrounds should be addressed.

Abortion, Induced↗
PubMed1995

A region of primer binding variation at the D6S265 locus associated with HLA-A25 and HLA-A26 antigens.

D6S265 is a polymorphic dinucleotide repeat, mapped within 70 kb centromeric of HLA-A, on chromosome 6p21.3. While genotyping families for genetic linkage analysis, allele non-amplification resulting in apparent non-Mendelian inheritance was observed at the D6S265 locus in 15 individuals, on chromosomes carrying the HLA-A25 and HLA-A26 antigens. The D6S265 locus was sequenced in a variant individual homozygous for allele non-amplification, and in a non-HLA-A25/-A26 individual, homozygous for D6S265 allele 1. Five base changes were identified in the reverse primer binding region of the variant individual, effectively preventing annealing of the 3' primer to the template.

Base Sequence↗
PubMed1995

In search of counterurbanisation: some evidence from Devon on the relationship between patterns of migration and motivation.

"The term counterurbanisation is frequently used to describe the redistribution of a population away from major cities and metropolitan areas and towards more rural areas. The widespread nature of this phenomenon has attracted much attention, yet the concept remains relatively under-developed, and even the basic definition lacks rigour. It is not surprising, therefore, that there has been a lack of cumulative evidence as to the extent of the process and little agreement as to its significance. In essence, ambiguity surrounds the types of movement that should be admitted, the necessary motives for movement and the appropriate measures for both. This paper offers some preliminary suggestions for a more structured approach to the problem. It draws on original survey data from Devon [England], a county which has experienced substantial net in-migration, both to examine the contribution of three alternative definitions of counterurbanisation and to consider how these issues relate to motivation."

Behavior↗
PubMed1995

Benzodiazepine use as a cause of cognitive impairment in elderly hospital inpatients.

BACKGROUND: Benzodiazepine drugs are used very frequently by the elderly and have been associated with a number of untoward events in them. In an earlier publication, we showed that there was an association between benzodiazepine use and episodes of confusion in hospital. The purpose of this study was to examine that association in more detail by studying only patients with intact cognitive function on admission and by taking into consideration a range of demographic, drug use, and clinical confounders. METHODS: A prospective cohort study was carried out of inpatients who had normal cognitive function on admission to hospital. The subjects were 418 hospital inpatients who had a normal result of a Mini-Mental State Examination (MMSE) performed within 24 hours of admission. They were aged 59-88 years. A clinical history and detailed drug use history were taken on admission and then the patients were followed prospectively for 10 days or until discharge, whichever was sooner. The MMSE was repeated every 2 days and all significant clinical events and episodes of delirium noted. RESULTS: 10.8% (95% Confidence Interval [CI]: 7.8-13.8%) of patients developed cognitive impairment (as indicated by a decrease in the MMSE). Factors that were statistically significantly related to the development of cognitive impairment included admission diagnoses of cancer or central nervous system (CNS) disease, alcohol consumption > 40 gms/day, hypoxia, and presence of benzodiazepines in the urine on admission. After adjusting for age, alcohol consumption, and admission diagnoses, those who reported taking benzodiazepines in daily doses equivalent to 5 mg or more of diazepam were at significantly higher risk of cognitive impairment than those who had not taken benzodiazepines (adjusted odds ratio = 3.5; 95% CI: 1.4-8.8). Twenty-one (5.0%, 95% CI: 2.9-7.1%) patients developed delirium as defined by the DSM-IIIR criteria. Age and hypoxia were statistically significantly related to the development of delirium. Due to the small number of cases of delirium, the power of the study to detect significant associations was low. CONCLUSIONS: Elderly hospital inpatients who have intact cognitive function on admission to hospital have a low risk of developing cognitive impairment and delirium during their hospital stay. In this population, however, benzodiazepine use accounted for 29% of cases of cognitive impairment which did occur. The data also suggest that dehydration, urinary retention, and an admission diagnosis of CNS disease may be important risk factors for delirium.

Aged↗
PubMed1995

Home-based management of children hospitalized with acute gastroenteritis.

OBJECTIVE: To determine the source of medical advice to parents and treatment administered at home for children admitted to hospital with acute gastroenteritis. METHODOLOGY: A questionnaire was completed by the parents of 231 children admitted during a 12 month period. RESULTS: The majority of children had seen their family doctor or an after-hours doctor prior to admission. Clear fluids were used for two-thirds but an oral rehydration solution (ORS) was used in only one-third of children. Medications were used for half, including antibiotics (19%), antidiarrhoeals (9%), antiemetics (7%) and paracetamol (27%). Inpatient assessment suggested that the majority of children had no or mild dehydration. CONCLUSIONS: Appropriate oral rehydration is underutilized and medications are overprescribed for the treatment of acute gastroenteritis. Family doctors continue to be the major source of advice for parents. Increased use of ORS at home may reduce hospitalization rates but attempts to change these practices should be directed at parents and family doctors.

Acute Disease↗
PubMed1995

Asthma knowledge, attitudes, and quality of life in adolescents.

Adolescents with asthma, their peers, and their teachers were studied in order to establish the level of knowledge concerning asthma and its management, their attitudes towards asthma, and the degree quality of life impairment due to asthma. A community survey was conducted among year 8 high school students (n = 4161) and their teachers (n = 1104). There was a good response rate to the questionnaires from students (93%) and teachers (61%). Twenty three per cent of students had asthma and this caused mild to moderate quality of life impairment, particularly with strenuous exercise. Asthma was provoked by passive smoke exposure in 30% of asthmatic students and up to 51% of students avoided situations because of asthma triggers. Asthma knowledge was low in teachers (mean score 14.90 out of a possible 31), students without asthma (11.25) and students with asthma (14.50). Specific knowledge on the prevention and treatment of exercise induced asthma was poor. There was a moderate degree of tolerance towards asthma among all three groups. Most considered internal locus of control as important, although students without asthma also considered chance to be a determinant of outcomes for people with asthma. Asthma is a common cause of quality of life impairment among year 8 high school students. Although specific knowledge on asthma is low, students and teachers hold favourable attitudes towards asthma. There are opportunities to intervene and improve asthma management among adolescents.

Adolescent↗
PubMed1994

Karyotype abnormalities in fetuses diagnosed as abnormal on ultrasound before 20 weeks' gestational age.

This study examined rates of karyotype abnormalities in fetuses diagnosed by ultrasound as abnormal before 20 weeks' gestational age and which prompted a follow-up amniocentesis or chorionic villus sampling. Those diagnosed before 20 weeks were compared with those diagnosed at or after 20 weeks. A retrospective study identified ultrasonographically abnormal fetuses in whom karyotyping had been undertaken, 306 fetuses before 20 weeks' gestational age and 241 after. Isolated malformations before 20 weeks had, on average, an 18 per cent risk of karyotype abnormality, compared with 20 per cent later. Specific rates were calculated; for example, heart abnormality was associated with karyotype abnormality in 7 per cent of cases before 20 weeks and in 14 per cent later. Multiple malformations and karyotype abnormalities were found together in 28 per cent of fetuses prior to 20 weeks and in 33 per cent of the older fetuses. Specific associations included nuchal oedema and trisomy 21 in 21 per cent of fetuses before 20 weeks. No karyotype abnormalities were found in fetuses diagnosed with choroid plexus cysts. An overview of trisomies in Victoria, in 1991, showed that 50 per cent of trisomy 18, 42 per cent of trisomy 13, and 9.5 per cent of trisomy 21 cases were identified by ultrasound in women less than 37 years of age. Another 28.6 per cent of trisomy 21 fetuses were detected in women of advanced maternal age who underwent amniocentesis or chorionic villus sampling, making a total of 38.1 per cent of trisomy 21 that were detected prenatally.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

The cost-effectiveness of different blood-cholesterol-lowering strategies in the prevention of coronary heart disease.

We aimed to compare the cost-effectiveness of two screening strategies and a population strategy for lowering blood cholesterol to prevent coronary heart disease. Census data, known risk-factor profiles, known coronary heart disease event rates and costs in 1988-89 Australian dollars for all men aged 35 to 64 in the Lower Hunter region of New South Wales (n = 67,651) were used to compare a high-risk strategy identifying and treating men with cholesterol levels above 6.5 mmol/L with diet and drug (cholestyramine), a moderate/high-risk strategy where in addition diet counselling was offered to those with levels 5.5 to 6.5 mmol/L, and a population strategy where the diet of the whole population was changed regardless of blood cholesterol. Costs of implementing strategies, heart disease events saved, discounted and undiscounted cost-effectiveness ratios and savings in initial treatment costs over five years were measured. For the high-risk, moderate/high-risk and population strategies, the costs of implementation were $50.1m, $53.1m and $5.4m respectively; the numbers of events saved were 104, 144, 116 respectively; cost-effectiveness ratios were $482,224, $369,098, $46,667 (per event saved) respectively. Cost savings for each strategy were approximately half a million dollars. The moderate/high-risk strategy was more cost-effective than the high-risk strategy but the population strategy cost one-tenth that of the two screening strategies per event saved. More research is required to design and test strategies that alter the eating habits of the whole population.

Adult↗
PubMed1994

A new method of estimating cost effectiveness of cholesterol reduction therapy for prevention of heart disease.

The purpose of this study was to demonstrate a new method of estimating the cost effectiveness of interventions that lower blood cholesterol levels in the prevention of coronary heart disease (CHD) at the community level. The participants in the study were 67 651 men aged 35 to 64 years in the Lower Hunter region of New South Wales, Australia. Census data, risk factor profiles and CHD event rates from community surveillance, plus costs in 1988-1989 Australian dollars, were used as inputs to a computer program that used a logistic equation. The output estimated the CHD events avoided and the cost effectiveness of an intervention that identified and treated men with cholesterol levels greater than 6.5 mmol/L with dietary modification and cholestyramine. The cost of implementation of the intervention was $A50.1 million to prevent 104 CHD events. The cost-effectiveness ratio was $A482 224 per CHD event avoided (SD = $A24 761) and the direct medical costs avoided were approximately $A500 000 over a 5-year period ($A4535.07 per CHD event avoided). Drug acquisition costs contributed substantially (88%) to the total costs of interventions that rely on screening to identify individuals with high cholesterol for intensive treatment.

Adult↗