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Biomedical subjects

G Hunter

Publications and source records attributed to G Hunter.

At least 55 records · Page 3Linked to original sources
PubMed1996

Cross-calibration of body-composition techniques against dual-energy X-ray absorptiometry in young children.

Using dual-energy X-ray absorptiometry (DXA) as a standard method for determining body composition in children, we evaluated the accuracy of skinfold-thickness measurements (with the Slaughter et al equations, which are based on triceps and calf skinfold-thickness measurements), bioelectrical resistance (BR; with the Kushner el al equations and age-specific hydration constants), and other clinical measurements (individual skinfold thicknesses and body mass index) for the assessment of body fat in children. We studied a heterogenous group of 49 boys and 49 girls, aged 6.6 +/- 1.4 y and weighing 24.1 +/- 5.9 kg. Fat mass estimated by DXA was significantly lower than fat mass measured by skinfold thickness, even though fat mass measurements by these two techniques were strongly related to each other. Fat mass estimated by DXA was also significantly lower than fat mass measured by BR, and the model R2 and SEE were not as strong as for the skinfold-thickness technique. Fat mass estimated by DXA also correlated with other clinical indexes such as triceps skinfold thickness, body mass index, body weight, and subscapular skinfold thickness. In forward-regression analysis, subscapular skinfold thickness, body weight, triceps skinfold thickness, sex, and height2/resistance estimated the value for fat mass measured by DXA with a model R2 of 0.91 and an SEE of 0.94 kg fat mass. These studies suggest that existing techniques for assessing body fat in children may be inaccurate. We provide new anthropometric equations based on the use of DXA as a criterion that provide accurate and precise measures of body fat and fat-free mass in white children aged 4-9 y. This approach provides estimates of body fat standardized to a known laboratory standard of chemical analysis of carcasses.

Absorptiometry, Photon↗
PubMed1996

Cardiorespiratory responses of patients with rheumatoid arthritis during bicycle riding and running in water.

BACKGROUND AND PURPOSE: The purpose of this study was to compare exercise during dry-land bicycle ergometry and running in water with a flotation device in individuals with rheumatoid arthritis. SUBJECTS: Eight individuals with adult-onset rheumatoid arthritis, between the ages of 30 and 40 years (X = 35.88, SD = 2.85), participated. METHODS: Each subject did a graded maximal exercise test on a stationary bicycle and in the water wearing a flotation device, while oxygen uptake (VO2), heart rate (HR), pain, rating of perceived exertion (RPE), minute ventilation (VE), respiration rate, tidal volume (VT), and respiratory exchange ratio (R) were monitored. RESULTS: Higher maximum RPE and R were seen during water running, whereas higher VE and VT were seen during bicycle riding. Heart rate, R, and plateauing VO2 data indicated that a true physiological peak VO2 was reached during the bicycle test. Peak VO2 and HR were similar for either water or bicycle exercise. These findings show that with both forms of exercise, subjects were able to reach training levels as set by the American College of Sports Medicine. CONCLUSION AND DISCUSSION: The water exercise, therefore, provides a means of exercising for individuals with rheumatoid arthritis. It allows them to reach the needed training levels in a comfortable aquatic environment.

Adult↗
PubMed1995

Differential expression of the L10 ribosomal protein during heart development.

Neural crest cells originating from the posterior rhombencephalon migrate to the cardiac outflow tract and participate in division of the aorta and pulmonary trunk. Ablation of this region of premigratory neural crest in the chick embryos results in nondivision of the outflow vessels. Subtractive hybridization was used to identify messages in the outflow tract of embryos with cardiac neural crest cells versus those lacking the cardiac neural crest cells. The chick L10 ribosomal protein was found to be differentially expressed in the outflow tract of embryos with cardiac neural crest. Several conditions have been identified that involve differential expression of ribosomal proteins, but this is the first report of differential expression in eukaryotic embryonic development.

Amino Acid Sequence↗
PubMed1994

Determination of the depth of cure for VLC composites by nuclear magnetic resonance microimaging.

OBJECTIVES: The purpose of this study was to evaluate the potential of nuclear magnetic resonance microimaging (NMRM) for investigating the depth of cure for visible light curing of dental composite materials. METHODS: Cylindrical composite specimens were light-cured within the NMRM instrument for predetermined times. Vertical slice, mid-resolution, spin-echo images were acquired using a Bruker AM300WB instrument with a Bruker microimaging attachment. Images were digitized and intensity profiles generated using deuterium oxide/water as a reference intensity. Separate specimens were made to obtain Vickers microhardness values as a function of depth to compare an established method for determining depth of cure with NMRM. RESULTS: A difference in NMR image intensity between uncured and cured composite resin has been detected. Values for integrated intensities were obtained at 150 microns intervals over the mid-fifth of the total image width. An abrupt transition was not seen at the cure front which advances with cumulative exposure time. NMRM produced similar data trends to microhardness measurement. SIGNIFICANCE: NMRM produces three-dimensional images of "mobile" hydrogen nuclei to a resolution of 10(-5) mm3. It is non-invasive, non-destructive and able to selectively image protons in different chemical environments. It can be used to investigate depth of cure for light curing materials, but must be regarded as a research technique and not one for routine measurement. Refinement is necessary, possible, and in progress to improve resolution from the present 10(-2) mm3 towards the limit, and to reduce noise.

Composite Resins↗
PubMed1994

HIV prevalence no higher among female drug injectors also involved in prostitution.

To assess the prevalence of HIV infection among female drug injectors involved in prostitution and female drug injectors not involved in prostitution, survey-based interviews were undertaken with 308 female drug injectors in 1990 and 1991. Confirmed saliva test results show 12.9% HIV prevalence among female drug injectors involved in prostitution and 14.4% HIV prevalence among drug injectors not involved in prostitution. This gives an HIV prevalence rate of 14.2% among female drug injectors overall. Findings also show that women not involved in prostitution were less likely to be in contact with a drug treatment or helping agency and were less likely to report having had an HIV test. Respondents in contact with a treatment agency and respondents involved in prostitution were more likely to be aware of their HIV status, and 72% of non-prostitute women confirmed HIV positive were unaware of their positive status. These findings of no higher HIV prevalence among female drug injectors also involved in prostitution lend some support to emerging evidence which associates HIV transmission among women prostitutes with an involvement in injecting drug use rather than with an involvement in prostitution per se. Findings also strengthen the need for greater expansion and greater accessibility of HIV testing, counselling and prevention facilities in community locales where drug injection and prostitution is prevalent.

Adolescent↗
PubMed1994

Mucormycosis: emerging prominence of cutaneous infections.

Twenty-five patients with mucormycosis were seen at two university-affiliated hospitals from 1979 to 1993. These cases included 10 cutaneous, 9 rhinocerebral, and 3 disseminated infections, as well as one case each of pulmonary, renal, and peritoneal dialysis catheter-related infection. Eleven of the patients were diabetic and seven had ketoacidosis, including four who became acidotic after admission to the hospital. The mortality rates associated with rhinocerebral, disseminated, and pulmonary infections were 78%-100%, while those associated with cutaneous and miscellaneous forms were zero. In view of the prominence of cutaneous infections, the 10 cases of cutaneous mucormycosis (in addition to a case from a community hospital) are reported in detail. Systemic diseases were present in four of the 11 patients. Local factors leading to infection were identified in nine of the cases and included motor vehicle accident-related and other trauma, surgery, a spider bite, and an intravenous infusion catheter. The cases of cutaneous mucormycosis reported in the literature have been analyzed for identification of predisposing factors, treatment, and outcome. Aggressive surgical debridement is the most important component of therapy, and administration of amphotericin B is a useful adjunct. Skin grafting is useful as a method of repairing defects left by extensive debridement.

Adolescent↗
PubMed1994

Sexual behaviour of drug injectors in London: implications for HIV transmission and HIV prevention.

The importance of sharing injecting equipment in the transmission dynamics of HIV is well established. Comparatively less is known about the sexual behaviour of drug injectors and the risks posed to themselves and their sexual partners through the sexual transmission of HIV. Findings are reported from survey-based interviews undertaken in 1991 which investigated the sexual behaviour of 516 drug injectors, both in and out of treatment in London. The majority of respondents (80%) were sexually active in the 6 months preceding interview. During this time, respondents had a mean of 2.1 non-commercial opposite sex partners. Most (66%) had vaginal intercourse at least once a week, although 68% never used condoms with primary partners and 34% never used condoms with casual partners. Those having sexual intercourse most often were less likely to use condoms. Many had non-injecting sexual partners, and 62% of respondents' primary and casual partners did not inject drugs. Confirmed saliva HIV test results show 10% of respondents to be antibody positive, with a higher rate of prevalence (14% positive) among those with no experience of treatment. This group were also more likely to report casual sexual intercourse. The average rate of partner change, the high proportion of drug injectors with non-injecting partners and the infrequency of condom use within primary and causal relationships indicates the potential for HIV transmission between injectors and their non-injecting sexual partners. The paper concludes by emphasizing the importance of outreach and community-based intervention in safer sex health promotion.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Risk of nonshunt abdominal operation in the patient with cirrhosis.

BACKGROUND: The hazards of operative treatment for variceal hemorrhage and intractable ascites in patients with cirrhosis are well known. Much less information is available on the morbidity and mortality in these patients after abdominal operations not directly related to the sequelae of portal hypertension. STUDY DESIGN: We reviewed the records of 77 consecutive histologically proved cases of cirrhosis in patients undergoing 85 general surgical, abdominal procedures during a ten year period. Logistic regression analysis was done on 32 preoperative and intraoperative variables with relation to postoperative outcome. RESULTS: There were 47 men and 30 women, with a mean age of 61 years (range of 28 to 86 years). The 30-day mortality rate was 18 percent (15 of 77 patients). Emergent operation was associated with a mortality rate of 32 percent (11 of 35 patients) compared with 8 percent (four of 50 patients) after elective procedures (p < 0.05). Extensive complications occurred in 28 percent of patients (24 patients; 14 percent after elective operative treatment and 49 percent after emergent procedures). The mortality rate was greatest after gastric procedures (38 percent). Other factors of statistical significance (p < 0.05) associated with poor postoperative outcome included cachexia, preoperative transfusion of fresh frozen plasma, and intraoperative platelet transfusion. Surprisingly, operative blood loss, presence of ascites, and operative time were not associated with increased complications or death. CONCLUSIONS: We conclude that elective, nonshunt abdominal operations can be performed with acceptable morbidity and mortality rates in selected patients with cirrhosis.

Abdomen↗
PubMed1993

The failure of conventional methods to promote spontaneous transpyloric feeding tube passage and the safety of intragastric feeding in the critically ill ventilated patient.

Nasoenteral tube feedings are often recommended in critically ill patients when gastrointestinal tract function is intact. Conventional methods of placement include turning the patient on the right side and the use of drugs that stimulate peristalsis to promote transpyloric passage. A prospective study was initially performed to assess the success of conventional methods used to promote transpyloric feeding tube placement in patients requiring assisted ventilation admitted to the Surgical Intensive Care Unit (SICU) (Part I of the study). In 68 critically ill ventilated patients, placement of nasoduodenal feeding tubes was attempted. Successful transpyloric placement was achieved in only ten patients. There was no correlation between age, gender, admitting diagnosis, time of tube placement and successful placement. The second part of the study was initiated to assess the safety of nasogastric feeding in critically ill ventilated patients. Forty-two patients admitted to the SICU were considered candidates for gastrointestinal tract feeding and were fed through the gastric route. Twenty-five patients reached enteral feeding goal rate within 72 hours, while 34 patients achieved goal rate by five days. Eight patients required total parenteral nutrition to meet nutritional needs because of an inability to achieve adequate nutritional support enterally. There were 11 complications noted in ten patients, including one episode of aspiration pneumonia. The presence of complications was not related to age, gender, admitting diagnosis, infusion method or type of formula used. Duodenal intubation using conventional methods in critically ill ventilated patients is unsuccessful in most patients. Nasogastric feeding in this group of patients can be safely administered in selected instances.

Critical Illness↗
PubMed1992

Effect of weight reduction on resting energy expenditure, substrate utilization, and the thermic effect of food in moderately obese women.

It is not known whether the decrease in the thermic effect of food (TEF) in obesity is a consequence of obesity or a factor contributing to the development of obesity. The resting energy expenditure (REE) of 24 obese, nondiabetic, postmenopausal women was 5481 +/- 110 kJ/24 h (1310 +/- 26.4 kcal/24 h). After weight loss (12.7 +/- 0.45 kg) the REE was significantly decreased (4858 +/- 94 kJ/24 h, or 1161 +/- 22.4 kcal/24 h) and equivalent to the REE of 4866 +/- 119 kJ/24 h (1163 +/- 28.5 kcal/24 h) in 24 never-obese, postmenopausal women. The TEF, expressed as a percentage of the calories ingested, was 8.2 +/- 0.50% for obese subjects, 8.7 +/- 0.57% for postobese subjects, and 9.8 +/- 0.54% for never-obese subjects. Compared with never-obese subjects, the TEF was significantly reduced in obese subjects (P = 0.043) and remained unchanged after weight loss (P = 0.341). These findings indicate that the lower TEF in the obese subjects is uncorrected by weight loss, and thus it is a contributor to obesity rather than a consequence of obesity.

Aged↗
PubMed1992

Dietary factors and fracture in postmenopausal women: a case-control study.

This case-control study examined the effect of diet on the risk of postmenopausal fracture of the hip and wrist. Cases, women aged 50-84 years, were admitted to one of four Metropolitan Toronto hospitals during the period September 1983 through May 1985. Controls were women of the same age, admitted to the same hospitals, and seen for orthopaedic or general surgical complaints. Data were collected through the use of a standardized structured questionnaire administered by trained female interviewers, and included dietary, sociodemographic, medical, and behavioural variables. Data analysis was conducted on 102 hip fracture cases, 154 wrist fracture cases, and 277 controls. Higher dietary calcium intake only slightly increased the risk of hip fracture; however, it was associated with a significantly decreased risk for fracture of the wrist, at the level > or = 1 g/day. Coffee and tea consumption appeared to be unrelated to fracture risk. Finally, alcohol intake was associated with a statistically nonsignificant increased risk in both fracture types. These findings point to the importance of dietary factors on fracture risk, and indicate a need for future studies to stratify analysis on the basis of fracture type.

Aged↗
PubMed1992

A new method of diagnosing diaphragmatic injury using intraperitoneal technetium: case report.

The diagnosis of diaphragmatic laceration following blunt or penetrating trauma is often difficult to establish. Delay in recognition of this injury can be life threatening, resulting in herniation of abdominal viscera with possible strangulation or respiratory embarrassment. Previous animal studies from our institution have documented that intra-abdominal instillation of technetium sulfur colloid is a sensitive method to diagnose diaphragmatic disruption. We now present a case of diaphragmatic injury where the preoperative diagnosis was accurately made using this method when other imaging studies were inconclusive.

Adult↗
PubMed1991

Value of lymph node biopsy in the treatment of patients with the human immunodeficiency virus.

The indications and value of lymph node biopsy in patients infected with the human immunodeficiency virus (HIV) are not clearly defined. We reviewed 29 consecutive lymph node biopsies performed on 24 patients with the HIV over a 4-year period. Indications for biopsy included: (1) new or worsening medical symptoms with no detectable etiology in patients with lymphadenopathy, (2) disproportionately larger or enlarging lymph node in patients with generalized adenopathy, and (3) exclusion of concomitant disease in patients with previously defined infectious or neoplastic processes. The biopsy samples exhibited a diversity of histologic appearances including atypical and reactive hyperplasia, malignancy, and infection. Nineteen biopsies (64%) resulted in the institution or alteration of treatment. The absolute number of T-helper cells prior to biopsy was significantly lower in patients with a diagnosis of malignancy or infection (p < 0.05), as well as in those who eventually died (p < 0.05). Four (14%) minor complications resulted from lymph node biopsy. Based on our results, we conclude that lymph node biopsy is indicated in the above three subsets of HIV-infected patients. Biopsy can be performed with minimal morbidity and significantly alters therapy in the majority of patients.

AIDS-Related Complex↗
PubMed1991

Scottish cocaine users: wealthy snorters or delinquent smokers?

Ninety-two cocaine users were interviewed in Scotland. Most were middle-class nasal users, also used other drugs and generally gave cocaine a positive rating. One half of them had at some time used cocaine more than once a week. For some, this period lasted some months, when as much as 30 'lines' of cocaine were used per day of cocaine use. More of these heavy users reported adverse effects of cocaine than was the case for light users. Nonetheless, most heavy users had reduced their use by themselves to the point that their current cocaine use was no different from that of light users. Possible explanations for this apparently spontaneous reduction are discussed.

Adolescent↗