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Biomedical subjects

D Hill

Publications and source records attributed to D Hill.

At least 91 records · Page 5Linked to original sources
PubMed1999

Management of renovascular disease: a review of renal artery stenting in ten studies.

To evaluate the efficacy and safety of renal artery stents in renovascular disease, we identified 10 descriptive studies containing sufficient information for systematic evaluation. No randomized comparisons of stenting with angioplasty or with surgery were found. Overall, stents were placed in 416 renal arteries in 379 patients, mean age 64 years (range 27-84), 56% male. Of the stenoses, 97% were atheromatous (inter-study range 71-100%), 80% ostial (22-100%) and 31% bilateral (12-87%). The clinical indication for stenting was usually hypertension with or without mild renal impairment. Radiological indications for stenting were: narrowing of > or = 50% (in 9/10 studies) as a result of elastic recoil (58%) or dissection (2%) at the time of angioplasty; restenosis some time after angioplasty (15%); or as a primary procedure (25%). Technical success was reported in 96-100% of procedures. Restenosis (> or = 50% narrowing), evaluated in 312/416 (75%) arteries, generally between 6 and 12 months, was 16% overall. Hypertension was cured by stenting (DBP < or = 90 mmHg on no treatment) in 34/379 (9%) overall and in 34/207 (16%) of those whose renal function was normal initially. Six of 379 (1.6%) patients died within 30 days of stenting, but in only two (0.5%) was death judged to be procedure-related. Complications, other than those which led to dialysis, occurred in 42/379 (13%) patients, one third requiring intervention, ranging from blood transfusion to a surgical bypass procedure. Renal function as judged by serum creatinine concentration (SCC) improved in 26%, stabilized in 48% and deteriorated in 26% of patients whose renal function was impaired initially (SCC > 133 mumol/l). In one study, with average baseline SCC > 200 mumol/l, successful stenting slowed the rate of progression of renal failure when renal function was deteriorating beforehand. Nine of 379 (2.4%) patients, including 7/14 (50%) whose SCC was > or = 400 mumol/l initially, required dialysis after stenting. Stenting should be offered by specialist centres as a secondary procedure for unsuccessful angioplasty, or restenosis following angioplasty, to patients with renovascular disease and uncontrolled hypertension, advancing renal failure or pulmonary oedema.

Age Distribution↗
PubMed1999

Tobacco use among Australian secondary students in 1996.

OBJECTIVES: To estimate smoking prevalence among Australian secondary students in 1996 and to examine trends in smoking prevalence since 1984. METHOD: A randomly selected representative sample of 434 secondary schools from across Australia participated in the study. At each school 80 randomly selected students completed a pencil-and-paper questionnaire anonymously. Data from 29,850 students aged between 12 and 17 years are reported. RESULTS: Current smoking (smoking in the week before the survey) was 8% in boys and 7% in girls aged 12, and rose to a peak prevalence among 17 year olds of 28% for boys and 34% for girls. The mean number of cigarettes smoked per week among current smokers rose from 11 for boys and six for girls aged 12 to 37 for boys and 34 for girls aged 17. Comparisons across survey years showed that while fewer 12 to 15 year olds were current smokers in 1996 than in 1984, the proportion in 1996 was greater than that in 1987 or 1990. Among 16 and 17 year olds, the proportion of current smokers in 1996 was greater than that seen in 1987 or 1990. An aggregate measure of tobacco involvement suggested that involvement with tobacco had remained stable since 1993 among 12 to 15 year olds. CONCLUSION: The decline in adolescent smoking seen in the late 1980s has stopped. IMPLICATIONS: Extrapolating from this survey, we estimate that more than 276,000 12-17 year old students were current smokers in 1996. If they all continue to smoke, 138,000 would die prematurely.

Adolescent↗
PubMed1999

Prevalence of illicit drug use among youth: results from the Australian School Students' Alcohol and Drugs Survey.

OBJECTIVE: To estimate the prevalence of illicit drug use among Australian secondary school students. METHOD: Data was collected as part of the Australian School Student's Alcohol and Drugs Survey, a national survey of 29,447 secondary school students. RESULTS: Of all students aged 12-17 years, 39.9% (44.1% of males and 35.9% of females) reported having used at least one illicit drug in their lifetime. Cannabis was the most widely used illicit drug with 36.4% of all students reporting having used cannabis. Substantially fewer students reported using other drugs: hallucinogens (8.6%), amphetamines (6.1%), cocaine (3.6%), ecstasy (3.6%), opiates (3.7%) and steroids (1.8%). There were clear gender and age differences in the prevalence of illicit drug use: more males than females reported illicit drug use and the lifetime prevalence of illicit drug use increased with age. Most of those who reported illicit drug use had used drugs on relatively few occasions although there was a small minority of the sample who reported more frequent use. Finally, there were strong association between regular cannabis use and the use of other illicit drugs in the past year, and moderate associations between illicit drug use and the extent of both tobacco and alcohol use. CONCLUSIONS: The findings of this, the first national survey of illicit drug use among Australian school students, indicate a high prevalence of illicit drug use. Comparisons with previous regionally based surveys suggest there may have been a recent increase in the prevalence of cannabis use and highlight the need for further monitoring of and prevention efforts aimed at reducing illicit drug use among students.

Adolescent↗
PubMed1999

Promoting sun protection in children: rationale and challenges.

This article outlines the epidemiological and educational arguments for promoting sun protection during childhood and highlights factors that may facilitate or hinder achievement of this behavioral outcome. A model describing behavioral factors in the causation of skin cancer is presented. Summary results from previous behavioral studies and interventions relating to primary prevention of skin cancer are described, and recent data on the cost-effectiveness of sun protection in Australia and its implications for health insurers are discussed. This article also includes a commentary on the demonstration projects promoting skin cancer prevention among children and their caregivers featured in this special issue of Health Education and Behavior.

Adolescent↗
PubMed1998

Second generation "peptoid" CCK-B receptor antagonists: identification and development of N-(adamantyloxycarbonyl)-alpha-methyl-(R)-tryptophan derivative (CI-1015) with an improved pharmacokinetic profile.

We have previously described the design and development of CI-988, a peptoid analogue of CCK-4 with excellent binding affinity and selectivity for the CCK-B receptor. Due to its anxiolytic profile in animal models of anxiety, this compound was developed as a clinical candidate. However, during its development, it was determined that CI-988 had low bioavailability in both rodent and nonrodent species. In the clinic, it was further established that CI-988 had poor bioavailability. Thus, there was a need to identify an analogue with an improved pharmacokinetic (PK) profile. The poor bioavailability was attributed to poor absorption and efficient hepatic extraction. We envisaged that reducing the molecular weight of the parent compound (5, MW = 614) would lead to better absorption. Thus, we synthesized a series of analogues in which the key alpha-methyltryptophan and adamantyloxycarbonyl moieties, required for receptor binding, were kept intact and the C-terminus was extensively modified. This SAR study led to the identification of tricyclo[3.3.1.1(3,7)]dec-2-yl [1S-[1 alpha(S*)2 beta]-[2-[(2-hydroxycyclohexyl)amino]-1-(1H-indol-3- ylmethyl)-1-methyl-2-oxoethyl]carbamate (CI-1015, 31) with binding affinities of 3.0 and 2900 nM for the CCK-B and CCK-A receptors, respectively. The compound showed CCK-B antagonist profile in the rat ventromedial hypothalamus assay with a Ke of 34 nM. It also showed an anxiolytic like profile orally in a standard anxiety paradigm (X-maze) with a minimum effective dose (MED) of 0.1 microgram/kg. Although the compound is less water soluble than CI-988, oral bioavailability in rat was improved nearly 10 times relative to CI-988 when dosed in HP beta CD. The blood-brain permeability of CI-1015 (31) was also enhanced relative to CI-988 (5). On the basis of the overall improved pharmacokinetic profile as well as enhanced brain penetration, CI-1015 (31) was chosen as a development candidate.

Adamantane↗
PubMed1998

Pharmacokinetics of methyl palmoxirate, an inhibitor of beta-oxidation, in rats and humans.

Recent studies from our laboratory have shown that methyl palmoxirate (MEP), an inhibitor of mitochondrial beta-oxidation of long chain fatty acids, can be used to increase incorporation of radiolabeled palmitic acid into brain lipids and reduce beta-oxidation of the fatty acid. Thus, MEP allows the use of carbon labeled palmitate for studying brain lipid metabolism in animals and humans by quantitative autoradiography or positron emission tomography (PET). As it is essential to pretreat human subjects with an acute dose of MEP prior to intravenous injection of [1-11C]palmitate for PET scanning, this study was undertaken to determine the plasma elimination half-life of MEP in rats and human subjects and to provide insight about the drug's absorption and metabolism. A gas chromatographic method was developed to measure MEP in body fluids. Following oral administration of MEP to rats (2.5 and 10 mg/kg) and to humans, the unmetabolized drug could not be detected in plasma or urine (sensitivity of detection was 1 ng). However, when MEP was injected intravenously (10 mg/kg) in rats, a peak initial concentration could be measured in plasma (7.7 microg/mL), the clearance of the drug from plasma was rapid (t1/2 = 0.6 min), which indicates that MEP readily enters tissue lipid pools or is metabolized like long-chain fatty acids. As no adverse experience occured in the 11 human subjects studied, oral administration of a single dose of MEP was safe under the conditions of this study and may be used to increase the incorporation of positron labeled palmitic acid for studying brain lipid metabolism in vivo by PET.

Administration, Oral↗
PubMed1998

Laparoscopic cholangiography: a prospective study.

BACKGROUND: The place of cholangiography has been controversial in the conventional and now in the laparoscopic setting. The aim of this study was to evaluate laparoscopic cholangiography and compare use of a portable C-arm image intensifier with conventional radiography. METHODS: One hundred and ninety-seven consecutive patients undergoing laparoscopic cholecystectomy were randomized before operation to cholangiography by either C-arm image intensifier or conventional radiography. Data were collected on a pro forma completed immediately after the operation. RESULTS: Cholangiography was successful in 93.0 per cent of patients. Cholangiography with an image intensifier was significantly faster. In 19 patients the ductal system was obscured by a cannula; in 17 of these cases a metal cannula was used. In 31.6 per cent of patients the clip on the cystic duct was within 1 cm or less of the common bile duct (CBD). CONCLUSION: Laparoscopic cholangiography is a safe procedure. Use of an image intensifier should be the preferred method of obtaining images. Metal cannulas are more likely to obscure the ductal system. The proximity of the clip on the cystic duct to the CBD highlights the potential for injury caused by electrocautery or erroneous clip application.

Adolescent↗
PubMed1998

Population-based prevalence of symptomatic and asymptomatic astrovirus infection in rural Mayan infants.

Symptomatic and asymptomatic astrovirus infection was prospectively determined in a 3-year birth cohort of Mayan infants. Stool samples from 271 infants and 268 older siblings were tested for astrovirus, adenovirus 40/41, rotavirus and Salmonella, Shigella and Campylobacter species. Concurrent diarrhea, vomiting, fever, or anorexia were noted. Astrovirus was detected in 164 infants (61%) and 20 siblings (7%). Rotavirus (4%) and adenovirus 40/41 (13%) were isolated less frequently. Of all diarrheal episodes reported at a visit, 26% (78/305) were associated with astrovirus; 17% (78/452) of astrovirus infections were associated with diarrhea and 9% with other symptoms. Only diarrhea was associated with astrovirus infection (odds ratio, 1.4; 95% confidence interval [CI], 1.07-1.92; P = .01). Of infants with astrovirus, 70% shed at multiple visits over a period of 2-17 weeks (median, 5). The point prevalence of astrovirus infection was significantly higher among infants than siblings (relative risk, 6.18; 95% CI, 3.93-9.72; P < .0001, chi2). Astrovirus was identified throughout the year, peaked in March and May, and decreased in September. In this population, astrovirus was the most common enteric pathogen isolated; symptomatic infection was prevalent among infants.

Adenoviridae Infections↗
PubMed1998

Reducing parenteral requirement in children with short bowel syndrome: impact of an amino acid-based complete infant formula.

BACKGROUND: The aim of this study was to assess the impact of an amino acid-based complete infant formula on enteral feeding tolerance and parenteral nutrition requirement in children with severe short bowel syndrome. METHODS: Four children (23 months-4.75 years) with short bowel syndrome who required long-term parenteral nutrition due to persistent feeding intolerance while receiving an extensively hydrolyzed formula were assessed before and after the commencement of an amino acid-based complete infant formula for a mean follow-up period of 48 months (range 39-51 months). Assessment included clinical monitoring of feeding tolerance and nutritional status, biochemistry, stool analysis, skin-prick testing to common food antigens, esophagogastroduodenoscopy and colonoscopy or jejunoscopy with biopsies, and measurement of disaccharidase levels and intestinal permeability. RESULTS: All patients ceased parenteral nutrition within 15 months as a result of decreased stool output and resolution of vomiting. Patients had a reduction in hospitalization (mean: 198 versus 98 days/patient/year), episodes of proven (mean: 4.3 versus 3.3/patient/year) and suspected (mean: 6.5 versus 4.0/ patient/year) bacterial sepsis and central line insertions (mean: 2.5 versus 1.5/patient/year). Intestinal permeability to lactulose fell markedly (mean: 69% versus 2.7%). Disaccharidase levels increased in all three patients undergoing repeat studies. CONCLUSIONS: An amino acid-based complete infant formula improved feeding tolerance and eliminated the need for parenteral nutrition in four children with short bowel syndrome who had previously required long-term parenteral nutrition. The clinical improvement was mirrored by improvement in measurements of intestinal function.

Acidosis↗
PubMed1998

Nondisruptive, in vivo method for biomechanical characterization of linear incision wound healing: preliminary report.

Previous work on in vivo biomechanical characterization of soft tissues and wound healing has led to the development of a methodology for nondisruptive, in vivo biomechanical analysis of linear incision wounds. The purpose of this preliminary study was to define nondisruptive biomechanical parameters that characterize progressive healing and compare them with an in vivo disruptive parameter of ultimate pressure at failure (in vivo strength). Male Sprague-Dawley rats (n = 60), each weighing 250 to 300 gm, were anesthetized and underwent creation of paired full-thickness linear incision wounds. The rats were divided into three groups (n = 10/group per time period): control group, nothing applied to either wound; carrier group, bovine serum albumin applied to each wound; transforming growth factor-beta2 group, transforming growth factor-beta2 in bovine serum albumin applied to each wound. On postoperative days 5 and 10, rats from each group underwent in vivo biomechanical testing using the Dimensional Analysis System (Dimensional Analysis Systems, Inc., Nashville, Tenn.). This computer-driven device integrates a video camera and processor with a vacuum controller, valve, and transducer to provide measurements of tissue deformation (in millimeters) and negative pressure (mmHg) as a multiaxial stress (vacuum) is applied to a wound. On each rat, one incision was tested disruptively and the other incision was tested nondisruptively. Disruptive data were measured as ultimate pressure (mmHg) at failure, or the amount of pressure required to disrupt the wound. Nondisruptive data were measured for tissue stiffness (kiloPascals) during application of negative pressure (maximum, 80 mmHg). On postoperative day 5, wounds treated with transforming growth factor-beta2 had significantly increased in vivo wound strength compared with carrier wounds. The nondisruptive parameter of tissue stiffness was also significantly increased for the transforming growth factor-beta2 treated wounds, thus supporting the disruptive data. On postoperative day 10, there was no difference in mean wound strength or mean tissue stiffness among any of the groups. These preliminary data represent the first report of in vivo, nondisruptive biomechanical characterization of linear incision wounds. The results suggest that through in vivo measurements of tissue stiffness, differences can be detected between treatment groups. Because the healing wound may be characterized without the need for disruption, this methodology should allow for consecutive, in vivo biomechanical testing of wounds in future wound healing studies.

Animals↗
PubMed1998

Resource utilization by injured automobile occupants and pedestrians.

BACKGROUND: This study was designed to test the hypothesis that the hospital resources utilized in treating pedestrian trauma would be significantly greater than that for automobile occupants. This was based on previous studies that showed that the demographic features and patterns of injury sustained by the pedestrian population were significantly different from that of automobile occupants. METHODS: A hospital-based study was designed utilizing retrospective analysis of a prospective trauma database. All primary retrievals of pedestrians (n=547) and automobile occupants (n=597) involved in accidents in Central Sydney from mid-1990 to mid-1995 were included. The length of hospital stay, use of the intensive care unit (ICU) and visits to the operating theatre (Standard Resource Cost) were compared. RESULTS: The age and injury severity scores were significantly higher for the pedestrian group. The length of stay (days) for the pedestrians (mean, 12 SD 14; median, 7 interquartile range (IQR) 13), was significantly higher (P < 0.0001 ) than that for the automobile occupants (mean, 7 SD 11; median, 2 IQR 6). The ICU utilization (days) for the pedestrians (mean, 1.3 SD 4.0; median, 0) was significantly higher (P < 0.0001) than that of the automobile occupants (mean, 0.6 SD 2.9; median, 0). The average operating theatre utilization per pedestrian (0.65 visits) exceeded that of automobile occupants (0.43) by 50% (P < 0.0001). CONCLUSIONS: The study confirms that the acute care of pedestrian injury utilizes more hospital resources than that of automobile occupants. Resources should be allocated to meet this need both in terms of hospital reimbursement and overall directives in public health policy.

Accidents, Traffic↗
PubMed1998

Factors associated with pain following operative laparoscopy: a prospective observational study.

An open prospective observational study was performed, aiming to measure symptom severity following operative gynaecological laparoscopy and explore any associated factors. Women having concomitant procedures were excluded. Each woman had standardized analgesia, completed a symptom diary for 7 days postoperation, and had a standardized form completed by the surgeon detailing the operation. Back pain, nausea and vaginal pain were found to not be of clinical significance. Cutting major vessels, ligaments, vagina or ovary had major impacts on postoperative symptoms. In the presence of a standardized analgesic regimen, symptoms did not resolve for at least 5 days.

Abdominal Pain↗
PubMed1998

FGF-18, a novel member of the fibroblast growth factor family, stimulates hepatic and intestinal proliferation.

The fibroblast growth factors (FGFs) play key roles in controlling tissue growth, morphogenesis, and repair in animals. We have cloned a novel member of the FGF family, designated FGF-18, that is expressed primarily in the lungs and kidneys and at lower levels in the heart, testes, spleen, skeletal muscle, and brain. Sequence comparison indicates that FGF-18 is highly conserved between humans and mice and is most homologous to FGF-8 among the FGF family members. FGF-18 has a typical signal sequence and was glycosylated and secreted when it was transfected into 293-EBNA cells. Recombinant murine FGF-18 protein (rMuFGF-18) stimulated proliferation in the fibroblast cell line NIH 3T3 in vitro in a heparan sulfate-dependent manner. To examine its biological activity in vivo, rMuFGF-18 was injected into normal mice and ectopically overexpressed in transgenic mice by using a liver-specific promoter. Injection of rMuFGF-18 induced proliferation in a wide variety of tissues, including tissues of both epithelial and mesenchymal origin. The two tissues which appeared to be the primary targets of FGF-18 were the liver and small intestine, both of which exhibited histologic evidence of proliferation and showed significant gains in organ weight following 7 (sometimes 3) days of FGF-18 treatment. Transgenic mice that overexpressed FGF-18 in the liver also exhibited an increase in liver weight and hepatocellular proliferation. These results suggest that FGF-18 is a pleiotropic growth factor that stimulates proliferation in a number of tissues, most notably the liver and small intestine.

3T3 Cells↗
PubMed1998

Dietary treatment of hypercholesterolaemia: lack of relationship between individual response and genetic variation at the lipase loci. The Fluvastatin Genotyping Group.

The individual benefits of dietary therapy for hyperlipidaemia are known to be unpredictable. Variants at the lipoprotein lipase gene have been shown to associate with atherogenic lipoprotein phenotypes and the delayed clearance of triglyceride-rich lipoproteins. Together with variants of the closely homologous hepatic lipase gene, these may influence the extent of amelioration of plasma lipoprotein concentrations seen in dyslipidaemic patients treated with a low saturates/low cholesterol diet. We correlated the lipid changes seen following an 8-week diet in 83 subjects with primary hypercholesterolaemia (fasting plasma cholesterol > 6.5 mmol/L) with alleles of three restriction polymorphisms (LPL-Hind III and Pvu II; HL-Msp I). Although dietary changes produced a significant improvement in fasting lipids [total cholesterol falling by 5.2% (range -27.9% to +24.3%) and low-density lipoprotein cholesterol reduced by 6.0% (-30.5% to +29.3%)], no significant difference in response between different genotypes could be detected.

Adult↗
PubMed1998

A pilot study of tele-oncology in Scotland.

A pilot study of tele-oncology linking a cancer centre with a rural district general hospital was carried out; it involved patients, physicians, surgeons, radiologists and nursing staff. Its purpose was to complement the existing on-site outpatient services, providing oncological advice on non-clinic days. During the six months of the trial, 18 videoconferences were conducted. Their median duration was 17 min (range 7-40). Eight videoconferences involved patients directly. Acceptability of videoconferencing to doctors, nurses and patients was assessed by a questionnaire. Patients and staff found the technique acceptable and were satisfied with the results. The addition of a teleradiology system to teleconsultations was found to be important when decisions on patient management were taken. Following the success of this pilot trial, large studies of tele-oncology in the UK with measures of cost-effectiveness are needed.

Cost-Benefit Analysis↗