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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
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

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↗
PubMed1993

Limb deficiencies, chorion villus sampling, and advanced maternal age.

Record linkage between a prenatal diagnosis register and a congenital malformation register in the state of Victoria, Australia, has enabled further evaluation of the suggested association between limb deficiencies and early chorion villus sampling (CVS). We found 3 anomalies in this category after later CVS (i.e., 9 weeks and beyond), but our data suggest that advanced maternal age may be a risk factor for both terminal and all limb deficiencies. The data from Victoria are tabulated with data obtained from other registers. Different birth prevalence figures are obtained by different registers, therefore limiting comparisons between registers.

Adult↗
PubMed1993

Absorbed aluminium is found with two cytosolic protein fractions, other than ferritin, in the rat duodenum.

After in vivo perfusion of the upper intestine of the rat with a range of concentrations of aluminium chloride, entry of the metal into the portal system was only detected when the perfusate exceeded 400 mumol/l, suggesting a mucosal block. Using gel filtration of a mucosal cytosol extract, two consistently appearing aluminium peaks were identified which may represent aluminium binding proteins. Both were heat stable at 60 degrees C and had molecular sizes of about 700 (kilo daltons) (kD) and 17 kD respectively. The larger molecule was distinct from ferritin. Neither molecule associated with 59Fe nor 45Ca. It is suggested that the aluminium peaks are relatively specific aluminium binding proteins that have a scavenging role, reducing entry of the metal from the intestinal contents into the portal blood.

Aluminum↗
PubMed1993

Significant changes in gastrointestinal tract parasitic infections in children of St. Kitts over the 9-year period 1982-1991.

When 239 (1982) and 361 (1991) five- and nine-year-old children in St. Kitts were assessed for the presence of parasitic infections, there were significant reductions in the prevalence of trichuriasis from 83% to 58%, of ascariasis from 24% to 8.6% and of giardiasis from 15% to 9.4%. Anthelminthic use, which appeared to be the most important responsible intervention tool, remained roughly at the same level at 59-51%. However, the types of anthelminthics used changed over the period. Piperazine citrate, which was used by 66% in 1982, only had 35% usage in 1991. Albendazole which was not used at all in 1982 was taken by 32% of the children in 1991 and at the same time use of laevo-tetramisole increased by 20% from 14%. Suggestions are made for an island-wide mass intervention programme to manage parasitic infections.

Anthelmintics↗
PubMed1992

Physical and genetic mapping of the telomeric major histocompatibility complex region in man and relevance to the primary hemochromatosis gene (HFE).

We performed pulsed-field gel electrophoresis (PFGE) on genomic DNA from a radiation hybrid (RH) cell line and constructed a high-resolution physical map of the major histocompatibility complex class I region in 6p21.3, where the gene for primary hemochromatosis (HFE) is believed to be located. Due to the intact microsegment of hemizygous human genomic DNA preserved in the RH cell line, simplified and distinct restriction fragment banding patterns were generated. Using the RH cell line, we were able to extend the physical map of the HLA class I region to about 3000 kb, order the known HLA class I genes from centromere to telomere: HLA-B, -C, -E, (-A, -H, -G), and -F, and orient the HLA-F gene along the chromosome. The proximity of HLA-F to HLA-A was confirmed by linkage and linkage disequilibrium analysis. This study shows that RH cell lines can be useful for constructing long-range physical maps in specific regions of the human genome with PFGE. Physical and genetic mapping studies of this region are consistent with a localization of the HFE gene proximal or distal to HLA-A.

Animals↗
PubMed1992

Cell-mediated immune response after vasectomy in rats.

This study investigated the development of a cell-mediated immune response after vasectomy in Swiss Albino rats, by comparing the development of the thymus-dependent lymphoid tissue of the regional testicular lymph node and the spleen in vasectomized and in sham-operated control animals. Frozen sections were used and thymus-dependent regions were stained by immunocytochemistry. After vasectomy, the areas occupied by the paracortex in the lymph node sections showed a significant increase in size; the thymus-dependent regions of the spleen, in contrast, showed no change. The regional lymph node, rather than the spleen, seems to be important in cell-mediated and humoral immune responses to vasectomy.

Animals↗
PubMed1989

Activation of sodium channels is not essential for endothelin induced vasoconstriction.

The role of sodium and calcium ions in the vasoconstrictor response of isolated rat aorta and protal vein to synthetically prepared endothelin is investigated. Contractile responses to endothelin, unlike those induced by the sodium channel activator veratridine, are unaffected by tetrodotoxin or by the removal of sodium chloride from the solution bathing the tissue. The responses are the same whether sodium chloride is replaced iso-osmotically with either sucrose or potassium chloride. The endothelin responses in all media are entirely dependent on the presence of extracellular calcium, and can be blocked by 1 microM nitrendipine. These findings offer no support to the idea that voltage activated sodium channels are the primary site of action of endothelin as suggested by sequence homologies to scorpion alpha-toxins, but are entirely consistent with the possibility that the site of action of endothelin is closely coupled to the calcium channel (Yanagisawa et al, 1988).

Animals↗