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Biomedical subjects

D Hill

Publications and source records attributed to D Hill.

At least 37 records · Page 2Linked to original sources
PubMed2004

Preoperative localization of parathyroid adenomas: ultrasonography, sestamibi scintigraphy, or both?

Minimal access techniques are increasingly used to remove parathyroid adenomas. Such surgery depends on accurate preoperative localization but the selection of imaging modality remains controversial. We have reviewed the accuracy of ultrasonography, sestamibi scintigraphy and their combination in 48 cases of primary hyperparathyroidism. Ultrasound had a sensitivity of 64.3% (95% confidence interval 44.1-81.4) and positive predictive value (PPV) of 100% (81.5-100) for correct lateralization. Sestamibi had a sensitivity of 83.3% (69.8-92.5) and PPV of 87.1% (73.7-95.1). The simple combination of ultrasound with sestamibi had a sensitivity of 82.1% (63.1-93.9) and a PPV of 92.0% (74.0-99.0): little different from sestamibi alone. However, if the sestamibi result was disregarded in favour of ultrasonography in discordant cases, the sensitivity reached 96.4% (81.7-99.9) and the PPV was 100% (87.2-100). These results were not dependant on a learning curve or the size of adenoma.

Adenoma↗
PubMed2004

Neonatal congenital microvillus atrophy.

Congenital microvillous atrophy (CMVA) is the leading cause of neonatal secretory diarrhoea with onset either in the first 72 hours of life (early onset) or at 6-8 weeks after birth (late onset). To date over 30 cases have been reported worldwide. The prognosis for this life threatening condition continues to be poor. Therapeutic agents like somatostatin and epidermal growth factor are either ineffective or of marginal benefit. Overall five year survival after small bowel transplantation is currently approximately 50%. The following brief review is aimed towards helping neonatologists/perinatologists in the early diagnosis, and management of CMVA and in counselling the parents appropriately.

Atrophy↗
PubMed2003

Do adult focused anti-smoking campaigns have an impact on adolescents? The case of the Australian National Tobacco Campaign.

OBJECTIVES: To examine adolescents' awareness of and response to an adult focused anti-smoking advertising campaign. DESIGN AND SETTING: Data were obtained from two cross sectional surveys of adolescents. The first study, a national evaluation study, involved a telephone survey of a randomly selected sample of 400 14-17 year olds across Australia in 1998. The second study involved a survey of 3714 students aged 12-17 years, randomly selected from a probability sample of secondary schools in the Australian State of Victoria. MAIN OUTCOME MEASURES: In both surveys, adolescents answered questions on their awareness of the advertising campaign and actions taken in response to the campaign. Adolescents in the national evaluation study also answered questions assessing knowledge of health effects of smoking, impact of the campaign on adolescents, and relevance of the campaign for adolescents and other groups. Responses for smokers and nonsmokers were examined. RESULTS: Among the national evaluation sample, 85% of adolescent smokers thought the campaign was relevant to them. Fifty three per cent indicated that the campaign had led some teenagers to at least try to quit and 85% thought it made smoking seem less cool and desirable. Among students who were established smokers the campaign generated quitting activity, with 27% cutting down the number of cigarettes they smoked and 26% having thought about quitting. CONCLUSION: Results indicate that adolescents were very aware of this adult focused anti-smoking campaign and thought it relevant to them. The findings suggest that a graphic health effects cessation focused campaign may have been successful in promoting anti-smoking attitudes among adolescents.

Adolescent↗
PubMed2003

How has the prevalence of cigarette smoking changed among Australian adults? Trends in smoking prevalence between 1980 and 2001.

OBJECTIVE: To examine trends in the prevalence of cigarette smoking between 1980 and 2001 among several different sociodemographic groups within the Australian population. METHOD: National cross sectional surveys conducted by face to face interview every 3 years from 1980. Respondents were classified into five age groups and the occupation of respondents in the workforce were classified into one of upper or lower white collar or upper or lower blue collar. MAIN OUTCOME MEASURE: Prevalence of smoking at least weekly. RESULTS: The prevalence of smoking in 2001 was lower than that found in 1980 and this was true for all sociodemographic groups. Among adults smoking prevalence decreased from 35% in 1980 to 23% in 2001. The differential in smoking prevalence between men and women decreased between 1980 and 2001. Although smoking was more common among younger Australians (<24 years) than older Australians throughout the study, the differential between age groups reduced. For all years except 1980, the proportion of smokers among upper white collar workers was significantly lower than in all other occupation groups. CONCLUSION: There had been a continual decline in the prevalence of smoking among the Australian population since 1980. This decline had occurred across both sexes and in all age and occupation groups. Much of the decline in smoking prevalence between 1998 and 2001 was among blue collar worker group.

Adolescent↗
PubMed2003

Variation in plasma amino acid concentrations during a cycling competition.

AIM: The variations in plasma concentrations of 24 amino acids (AAs) were measured, taking into account modifications in plasma volume, in 7 male subjects, professional cyclists, during the first 2 stages (EI and EII) of the competition "4 Days of Dunkirk 1999". METHODS: Blood samples were taken before the start and at the end of each stage. At the end of EI a significant reduction (p<0.02) in alpha-aminobutyric acid was observed (-38%) and a significant increase (Wilcoxon 0.01<p<0.05) in cystine (+28%), phenylalanine (+21%), taurine (+33%) and tyrosine (+42%). Alanine in particular, and also the ramified AAs, remained relatively stable at this stage. At the end vs start of EII there was a significant reduction in several AAs, alpha-aminobutyric acid (33%), arginine (-21%), cystine (-15%), glycocholic acid (26%), hydroxyproline (-28%), leucine (-17%), lysine (-26%), methionine (-19%), threonine (-15%) and valine (-16%). RESULTS: The recovery period was characterised by increases in previously reduced AAs and vice versa. CONCLUSION: These results show that cellular use of plasma AAs in the endurance cyclist could differ between the first hours of competition and the subsequent stages, possibly in relation to the gradual increase in stress level as the stages progress; they also suggest that appropriate consideration should be given to the quality of protein inputs in the nutrition of cyclists involved in a high-level stage competition.

Adult↗
PubMed2003

Besnoitia oryctofelisi n. sp. (Protozoa: Apicomplexa) from domestic rabbits.

A species of Besnoitia from naturally infected rabbits from Argentina was propagated experimentally in mice, gerbils, rabbits, cats, and cell cultures. Cats fed tissue cysts from rabbits shed oocysts with a prepatent period of nine to 13 days. Sporulated oocysts were infective to gerbils, rabbits, outbred Swiss Webster and interferon gamma gene knockout mice. Bradyzoites were infective orally to gerbils and cats. Tachyzoites were successfully cultivated and maintained in vitro in bovine monocytes and African green monkey kidney cells. Schizonts were seen in the lamina propria of the small intestine of cats fed tissue cysts; the largest ones measured 52 x 45 microm. Schizonts were also present in mesenteric lymph nodes, livers, and other extra-intestinal organs of cats fed tissue cysts. Oocysts were 10-14 x 10-13 microm in size. This rabbit-derived species of Besnoitia resembled B. darlingi of the North American opossum, Didelphis virginiana with an opossum-cat cycle, but it was not transmissible to D. virginiana, and B. darlingi of opossums was not transmissible to rabbits. Based on biological, serological, antigenic, and molecular differences between the rabbit and the opossum Besnoitia, a new name, B. oryctofelisi is proposed for the parasite from domestic rabbits from Argentina.

Animals↗
PubMed2002

Taurine supplementation to a low protein diet during foetal and early postnatal life restores a normal proliferation and apoptosis of rat pancreatic islets.

AIMS/HYPOTHESIS: In our previous studies a low protein diet (8% vs 20%) given during foetal and early postnatal life induced abnormal development of the endocrine pancreas; beta-cell mass and islet-cell proliferation were reduced while apoptosis was increased. Taurine, an important amino acid for development was also reduced in maternal and foetal plasma of protein deficient animals. In this study we aim to evaluate the role of taurine in the alterations observed in rats after a low protein diet. METHODS: Four groups of rats were given either a control, a low protein, or control and low protein diets with 2.5% taurine in the drinking water. Diets were given to gestating and lactating mothers and to their pups until day 30. Beta and endocrine cell masses were analysed as well as DNA synthesis and apoptosis after taurine supplementation in foetuses and pups. We also investigated insulin like growth factor-II (IGF-II), inducible nitric oxide synthase (iNOS), and Fas by immunohistochemistry. RESULTS: In foetuses and neonates nourished with a low protein diet, taurine supplementation restored normal DNA synthesis and apoptosis. This led to adequate beta and endocrine cell mass in pups. In islet cells, immunoreactivity was increased for IGF-II, reduced for Fas and unchanged for iNOS after taurine supplementation. CONCLUSION/INTERPRETATION: Taurine supplementation to a low protein diet in foetal and early postnatal life prevents the abnormal development of the endocrine pancreas. The mechanisms by which taurine acts on DNA synthesis and apoptosis rate of endocrine cells involve IGF-II, Fas regulation but not iNOS.

Animals↗
PubMed2002

Culturability, injury and morphological dynamics of thermophilic Campylobacter spp. within a laboratory-based aquatic model system.

AIMS: To study the survival processes of thermophilic Campylobacter spp. within a modelled aquatic system and particularly the involvement and survival potential of viable but non-culturable forms. METHODS AND RESULTS: The survival and morphological characteristics of populations of thermophilic Campylobacter species exposed to simulated aquatic conditions were examined using a combination of cultural and microscopic techniques. Populations underwent progressive decay when exposed to simulated aquatic conditions. The rates of population decay were observed to be significantly greater at the higher temperature (20 degrees C) with a rapid transition of the dominant sub-populations from non-stressed to dead cells occurred within 3 days. At 10 degrees C the rate of culturability loss was much reduced with substantial development (approx. 80% of total population) of viable but non-culturable (VBNC) populations by all species within 3 days, declining to represent approximately 5-25% of the total population at day 60. Significant differences (P < 0.001) were identified between decay rates as a consequence of different species, sub-populations and temperature but not between sub-populations of different species. Morphological variants including spiral, elongated spirals and rods, short rods and coccoid forms were identified. The endpoints of morphological transition were temperature-independent and isolate-specific yet the rate of morphological transition was directly related to temperature and approximately equivalent between species. CONCLUSION: The VBNC state is a transitory stage in the degeneration of Campylobacter population within the aquatic environments simulated during this study. SIGNIFICANCE AND IMPACT OF THE STUDY: VBNC cells form the most persistent, viable, potentially pathogenic sub-population of Campylobacter populations exposed to aquatic stress conditions.

Bacteriological Techniques↗
PubMed2002

Toxoplasma gondii: transmission, diagnosis and prevention.

Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii, is one of the most common parasitic infections of man and other warm-blooded animals. It has been found world-wide from Alaska to Australia. Nearly one-third of humanity has been exposed to this parasite. In most adults it does not cause serious illness, but it can cause blindness and mental retardation in congenitally infected children and devastating disease in immunocompromised individuals.

Acquired Immunodeficiency Syndrome↗
PubMed2002

Carbapenem-resistant Acinetobacter and role of curtains in an outbreak in intensive care units.

Multiple-antibiotic-resistant Acinetobacter baumanii, including meropenem resistance, was first isolated from a patient in the general intensive care unit of a tertiary-referral university teaching hospital in Birmingham in December 1998. Similar strains were subsequently isolated from 12 other patients, including those on another intensive care unit within the hospital. The outbreak followed an increase in the use of meropenem in both the units. Environmental screening revealed the presence of the multiple-resistant Acinetobacter species on fomite surfaces in the intensive care unit and bed linen. The major source appeared to be the curtains surrounding patients' beds. Typing by pulsed field gel electrophoresis demonstrated that the patients' isolates and those from the environment were indistinguishable. Rigorous infection control measures including increased frequency of cleaning of the environment with hypochlorite (1000 ppm) and twice-weekly changing of curtains were implemented, along with restriction of meropenem use in the units. Isolation of the multiple-resistant Acinetobacter spp. subsequently diminished and it was not detected over a follow-up period of 18 months. To our knowledge, this is the first reported outbreak of carbapenem-resistant Acinetobacter spp. from the UK. This outbreak also highlights environmental sources, particularly dry fabrics such as curtains, as an important reservoir for dissemination of acinetobacters.

Acinetobacter↗
PubMed2002

High prevalence of viable Toxoplasma gondii infection in market weight pigs from a farm in Massachusetts.

The ingestion of uncooked infected meat is considered important in the epidemiology of Toxoplasma gondii infection in humans and little is known of the prevalence of viable T. gondii in meat used for human consumption in the United States. In the present study, viable T. gondii was isolated from 51 out of 55 pigs destined for human consumption. Hearts and tongues (500 g) from fifty-five 6-mo-old pigs from a farm in Massachusetts were bioassayed for T. gondii by feeding them to T. gondii-free cats. Feces of these cats were examined for shedding of T. gondii oocysts. Fifty-one of 55 cats fed pig tissues each shed 25-810 million T. gondii oocysts in their feces. Two of these cats consumed tissues of pigs that were shown to be seronegative with the Sabin-Feldman dye test, the modified agglutination test, and the Western blot. Results indicate that until examination of meat for T. gondii infection is implemented in slaughterhouses, all meat should be cooked according to industry guidelines before human consumption.

Agglutination Tests↗
PubMed2002

Prevalence of antibodies to Neospora caninum and Sarcocystis neurona in sera of domestic cats from Brazil.

Parasite Biology, Epidemiology and Systematics Laboratory, Animal and Natural Resources Institute, Agricultural Research Service, United States Department of Agriculture, Building 1001, Beltsville, Maryland 20705-2350 Antibodies to Neospora caninum and Sarcocystis neurona were determined in serum samples of 502 domestic cats from Brazil using direct agglutination tests with the respective antigens. Antibodies to S. neurona were not found in 1:50 dilution of any serum in the S. neurona agglutination test. suggesting that domestic cats from São Paulo city were not exposed to S. neurona sporocysts from opossums. Antibodies to N. caninum were found in 60 (11.9%) of 502 cats with titers of 1:40 in 36 cats, 1:80 in 18 cats, 1:160 in 5 cats, and 1:800 in 1 cat using the Neospora agglutination test (NAT). Antibodies to N. caninum were confirmed by Western blotting in the sera of 10 cats with NAT titers of 1:80 to 1:800; this finding suggests that at least 10 cats had N. caninum-specific antibodies confirmed by 2 tests. This is the first documentation of natural exposure of cats to N. caninum.

Agglutination Tests↗
PubMed2002

Brace monitoring system for the treatment of scoliosis.

Determining the efficacy of brace treatment for AIS has been hampered by poor data on the wear pattern of those children prescribed this treatment. Although there is some information on brace compliance, there is very little on how well the brace is secured and the resulting loads imposed on the trunk. The purpose of this study was to determine the daily brace wear pattern of adolescents prescribed Boston braces. The brace monitoring system consists of a force transducer and a microcomputer unit. A force transducer was placed in the lining of the Boston brace. The microcomputer unit was carried while the brace was worn. The force imposed by the brace pad during daily activity was recorded at 1 minute intervals over a period of 3 to 14 days. The samples were stored by the microcomputer. Five subjects (3F;2M; age: 14+/-2 years) who were to wear the brace full time were studied. The subjects adjusted their braces to a prescribed level of tightness as indicated by a light on the microcomputer. Overall compliance, compliance during school days, and forces imposed by the brace were analysed. The force provided by the Boston brace varies considerably during daily activity. Overall brace compliance was lower than expected, with 2 of 5 subjects wearing their brace infrequently. The compliance rate during school time was not different than during the rest of the study period. Peer pressure at school did not appear to affect brace compliance.

Adolescent↗
PubMed2002

Intelligent brace system for the treatment of scoliosis.

Measurement of the biomechanical effectiveness of a brace for the treatment of scoliosis has been hampered by the lack of compressive information about wear characteristics. Orthotists and orthopaedic surgeons believe that the effectiveness of bracing is correlated with the strap tensions. If the strap tensions can be maintained at the optimal level while patients wear their braces, a better treatment outcome may be obtained. However, strap tensions vary significantly during different activities. An intelligent brace system has been developed to control the strap tension so that the optimal prescribed level is maintained at all time. This system consists of an innovative strap tension transducer, a microcomputer unit and a motorized unit. The strap transducer has been developed with an accuracy +/- 1.0N in the range of 0 to 100N. An instrumented Boston brace was built to test the concept. When the strap tension was below 80% of the prescribed level for a 15 minutes interval, the microcomputer unit signaled the motor to tighten the strap. While the strap tension level was above 120% of the prescribed level for a 15 minutes interval, the motor reversed the direction. Laboratory testing results showed that the strap tension could be maintained at the optimal prescribed level.

Artificial Intelligence↗
PubMed2002

Spine-Straight device for the treatment of kyphosis.

Kyphosis is an excessive rounding of the upper spine. Its treatment depends upon the severity, the age of the patient and the levels of the spine that are affected. Early diagnosis is a key to providing optimal treatment. In a skeletally immature patient, an exercise program or bracing is the most commonly used treatment. However, the compliance of bracing for adolescents is poor and exercise training is labor intensive. The purpose of this study is to determine whether a Spine-Straight device can help patients to correct their kyphosis themselves and there by reduce back pain without the biomechanical support of a brace. The Spine-Straight device consists of an accelerometer and a microcomputer unit. The accelerometer is used to measure the kyphotic angle and the microcomputer unit controls a pager vibrator to alert patients when their posture exceeds personalized thresholds. The system was tested in the laboratory before used by subjects. The results were compared to back data obtained from a laser scanner imaging system. The maximum angle deviation between the laser scanner and the Spine-Straight device was 1.5 degrees. Two volunteers tested the systems for 2 days. The accelerometer was placed at the T3 location and the microcomputer unit was carried during daily activities. The angle measurement was recorded at 1 minute intervals during daily activity over a period of 2 days. The preliminary trials demonstrate subjects can improve their posture when feedback signals were provided.

Adult↗