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Biomedical subjects

B E Chatterton

Publications and source records attributed to B E Chatterton.

At least 19 recordsLinked to original sources
PubMed2000

The relation between bone density, free androgen index, and estradiol in men 60 to 70 years old.

The cause of age-related bone loss in men is poorly understood. Previous studies of the relationship between bone density and serum androgens have yielded inconsistent results, perhaps partly because age is a determinant of both. Recent studies suggest that serum estrogen levels influence bone density in adult men. In order to determine whether bone mineral density (BMD) and bone turnover are associated with serum sex steroids, we investigated 37 normal men within a narrow age range (60-70 years). Bone mineral density at the forearm, hip, and spine, testosterone, sex hormone binding globulin (SHBG), free androgen index (FAI:T/SHBG), estradiol (E), free estradiol index (FEI:E/SHBG), and markers of bone formation (alkaline phosphatase, osteocalcin, procollagen type I C-terminal extension peptide) and bone resorption (hydroxyproline/creatinine [OHPr/Cr], deoxypyridinoline/creatinine [Dpd/Cr], pyridinoline/creatinine, collagen type I cross-linked telopeptide) were measured. Bone mineral density was positively related (r > 0.35, p < 0.05 at all sites) to log FAI, whereas there was no significant relationship between BMD and either serum total testosterone, serum E, or FEI. Bone density at the spine and hip were inversely related to both OHPr/Cr (r > -0.41, p < 0.05 for all sites) and Dpd/Cr (r > -0.36, p < 0.05 for all sites). OHPr/Cr (r = -0.41, p < 0.05) and Dpd/Cr (r = -0.41, p < 0.05) were both inversely related to log FAI. We conclude that BMD and bone turnover in adult men are related to plasma free androgens.

Aged↗
PubMed1999

Reliability of sentinel node status in predicting axillary lymph node involvement in breast cancer.

OBJECTIVES: To assess the reliability of determining sentinel node status in staging regional lymph nodes in breast cancer. DESIGN AND SETTING: Prospective validation study in a major public teaching hospital, comparing histological sentinel node status with that of remaining axillary nodes. PATIENTS: 117 women who underwent sentinel node biopsy and axillary dissection for primary breast cancer between 1995 and 1998. MAIN OUTCOME MEASURES: Intraoperative success rate in sentinel node identification; false negative rate; predictive value of negative sentinel node status; overall accuracy of sentinel node status. RESULTS: The sentinel node was identified at operation in 95 patients (81.2%). Tumour involvement of the sentinel node was demonstrated in 29 of 31 women (93.5%; 95% CI, 79%-99%). Sixty-four of the 66 women in whom the sentinel node was negative for tumour showed no further involvement of remaining axillary nodes (standard haematoxylin-eosin histological assessment), giving a predictive value of negative sentinel node status of 97% (95% CI, 89%-100%). The overall accuracy in 95 women in whom sentinel node status was compared with axillary node status was 97.9%. CONCLUSIONS: Histopathological examination of the sentinel node is an accurate method of assessing axillary lymph node status in primary breast cancer and is likely to be incorporated into future surgical management of women with primary breast cancer.

Antimony↗
PubMed1999

In vivo real-time analysis of intraperitoneal radiolabeled tumor cell movement during laparoscopy.

PURPOSE: A porcine model has been developed to allow the real-time imaging of radiolabeled tumor cell movement throughout the peritoneal cavity, both at rest and during carbon dioxide insufflation. METHODS: Fifteen 30-kg domestic white female pigs were used. Under anesthesia, 15 to 20 million radiolabeled human colorectal tumor cells (LIM1215) were introduced into the peritoneal cavity under laparoscopic vision into the pelvis. Radiolabeled tumor cell movement was examined by using a 25-cm-diameter, low-energy mobile gamma camera with high resolution collimator. Tumor cell movement and distribution during two hours without insufflation was examined in four pigs. Then tumor cell movement and distribution during two hours with CO2 insufflation was examined in four pigs. In a further four pigs, tumor cells were then mixed with blood and injected into the peritoneal cavity and the effect of no insufflation vs. insufflation was noted. A further three pigs were examined with manipulation of the intra-abdominal contents after injection of LIM1215 cells into the peritoneal cavity. Venting insufflating CO2 was filtered for tumor cells. RESULTS: Widespread intraperitoneal distribution of tumor cells from the pelvis was identified both with CO2 insufflation of the peritoneal cavity and without insufflation. Tumor cells dispersed throughout the peritoneal cavity at a slower rate without carbon dioxide insufflation. There was a differential rate of tumor cell movement to the left upper quadrant and right upper quadrant with insufflation and without insufflation. Blood within the peritoneal cavity and an extended contact of the laparoscopic trocars with the peritoneal cavity in this setting increased contamination of the trocars and trocar sites with tumor cells. Tumor cells were identified on laparoscopic instruments in all experiments. No evidence of aerosolization of tumor cells was found. CONCLUSION: Tumor cells move throughout the peritoneal cavity both at rest and during CO2 insufflation. The pattern of tumor cell dispersion differs with CO2 insufflation. The presence of blood and extended contact of trocars with peritoneal contents are a major factor in trocar and trocar site tumor cell contamination.

Animals↗
PubMed1999

Effect of 3 weeks of detraining on the resting metabolic rate and body composition of trained males.

OBJECTIVE: To examine the hypothesis that detraining decreases the resting metabolic rate (RMR) of long-term exercisers. DESIGN: Eight pairs of subjects were matched for age, mass and training volume. They were then randomly allocated to either a control group (continue normal training) or detraining group (stop normal training but continue activities of daily living). SETTING: Exercise Physiology Laboratory, The Flinders University of South Australia. SUBJECTS: Sixteen male subjects (age 23.1 +/- 4.7 y (s.d.); mass 73.73 +/- 8.9 kg; VO2max 60.2 +/- 6.3 ml. kg-1.min-1; height 180.3 +/- 5.0 cm; body fat 14.6 +/- 5.4%) were selected from a pool of respondents to our advertisements. INTERVENTIONS: Each pair of subjects was measured before and after a 3-week experimental period. RESULTS: Two (groups) x 3 (2-, 3-and 4-compartment body composition models) ANOVAs were conducted on the difference between the pre- and post-treatment scores for percentage body fat, fat-free mass (FFM) and relative RMR (kJ.kg FFM-1.h-1). No significant between-group differences were identified except for the detraining group's small decrease in FFM (0.7 kg, P = 0.05). The main effects for body composition model were all significant; but the overall differences between the multicompartment models and the 2-compartment one were less than their technical errors of measurement. No significant interaction (P = 0.51) resulted from a 2 x 2 ANOVA on the pre- and post-treatment absolute RMR data for the control (315.2 and 311.9 kJ/h) and detraining groups (325.4 and 325.5 kJ/h). CONCLUSIONS: 3-weeks detraining is not associated with a decrease in RMR (kJ/h, kJ.kg FFM-1.h-1) in trained males; hence, our data do not support a potentiation of the RMR via exercise training. The greater sensitivity of the multicompartment models to detect changes in body composition was of marginal value.

Adult↗
PubMed1999

Resting metabolic rate, body composition and aerobic fitness comparisons between active and sedentary 54-71 year old males.

OBJECTIVE: To test the hypothesis that 55-70 y old male longterm exercisers (LE) have higher resting metabolic rates (RMR) than longterm nonexercisers (LNE). DESIGN: A power analysis demonstrated that this cross-sectional study required 12 subjects per group to detect a 10% RMR difference (kJ x kg FFM(-1) x d(-1)) between the LE and LNE (power = 0.8;alpha = 0.05). SUBJECTS: Twelve LE (X +/- s.d.; 63.5+/-3.4 y; 1.75+/-0.06 m; 69.01+/-8.24 kg; 20.4+/-4.9 %BF) and 12 LNE (63.6+/-5.6 y; 1.72+/-0.07 m; 79.44 12.4 kg; 29.6 4.4 %BF) were recruited from advertisements placed in a newspaper and on university and community noticeboards. INTERVENTIONS: Measurements were conducted for: RMR using the Douglas bag technique; body composition via a four compartment model which is based on determination of body density, total body water and bone mineral mass; and aerobic fitness using a submaximal work test on a cycle ergometer. RESULTS: The LE (93.00+/-7.16 kJ x kg(-1) x d(-1)) registered a significantly greater (P = 0.04) RMR than the LNE (84.70+/-11.23 kJ x kg(-1) x d(-1)) when energy expenditure was expressed relative to body mass, but this difference disappeared (P = 0.55) when the data were corrected for the non-zero intercept of the graph of RMR (MJ/d) against body mass. ANCOVA with FFM as the covariate also indicated that the RMR (MJ/d) difference between the groups was not statistically significant (P = 0.28). The adjusted means for the LE and LNE were 6.39 and 6.62 MJ/d, respectively. CONCLUSIONS: There are no RMR (MJ/d) differences between LE and LNE 54-71 y old males when statistical control is exerted for the effect of FFM and the higher value of the former group for RMR normalised to body mass disappears when this ratio is corrected for statistical bias.

Aged↗
PubMed1999

Bone growth from 11 to 17 years: relationship to growth, gender and changes with pubertal status including timing of menarche.

The tempo and change in bone growth during puberty in relation to physical growth is described in a cohort of 56 boys and 52 girls. Distal forearm bone width, mineral content and volumetric density, anthropometry and pubertal status were measured at ages 11, 13, 15 and 17 y, and bone age at 17 y. Bone width and mineral content increased independently with age for each pubertal stage. Volumetric density fell during early puberty and then increased rapidly. Maximal increase of all bone variables occurred earlier in girls than in boys and earliest for bone width, then mineral content, then density. In girls most change occurred in the 12 mo before and after menarche. The degree of tracking was similar to that for height. Bone growth followed physical growth but at a slower tempo. By age 17 y boys had attained 86% of the reference adult bone mineral content and volumetric density; girls had attained 93% of the reference adult bone mineral content and 94% of volumetric density. Those skeletally mature at 17 y had greater mineral content and volumetric density. To maximize peak bone mass, modifiable environmental factors should be optimized before the onset of puberty and be maintained throughout this period of rapid growth and beyond attainment of sexual maturity.

Adolescent↗
PubMed1999

Familial and environmental influences on bone growth from 11-17 years.

The influences on bone growth of familial factors, nutrition and physical activity are described in a cohort of 108 children (56M, 52F). Distal forearm bone width, mineral content and volumetric density, anthropometry, pubertal status, nutritional intake and physical activity were measured at ages 11, 13, 15 and 17 y. Parental forearm bone status was also determined. Both mothers' and fathers' bone variables were significant predictors of the respective children's bone variables, but heritability estimates were greater between mothers and their children than between fathers and their children. By age 17 y boys had attained 101%, 85% and 89% of their fathers' height, bone mineral content and volumetric density, respectively; girls had attained 103%, 95% and 98% of their mothers' height, bone mineral content and volumetric density, respectively. There were no consistent associations among nutrient variables and bone status or rate of change in bone status. However, there was a significantly greater increase in bone mineral content and density from 11-17 y in those girls with consistently high calcium intake. There were no significant correlations between physical activity and bone values or rate of change of bone values. Age, gender, pubertal status, height, weight and parental bone values accounted for 80%, 71% and 49% of the variance of bone mineral content, bone width and volumetric density, respectively and 52%, 55% and 58% respectively of the variance of change in these variables. After age, gender, sexual maturity and body size, heritability accounts for the greatest variance in bone values through adolescence.

Adolescent↗
PubMed1999

Segmental colonic transit after oral 67Ga-citrate in healthy subjects and those with chronic idiopathic constipation.

UNLABELLED: Measurement of segmental colonic transit is important in the assessment of patients with severe constipation. 111In-diethylenetriamine pentaacetic acid (DTPA) has been established as the tracer of choice for these studies, but it is expensive and not readily available. 67Ga-citrate is an inexpensive tracer and when given orally is not absorbed from the bowel. It was compared with 111In-DTPA in colonic transit studies in nonconstipated control subjects and then in patients with idiopathic constipation. METHODS: Studies were performed after oral administration of 3 MBq (81 microCi) 67Ga-citrate or 4 MBq (108 microCi) 111In-DTPA in solution. Serial abdominal images were performed up to 96 h postinjection, and computer data were generated from geometric mean images of segmental retention of tracer, mean activity profiles and a colonic tracer half-clearance time. RESULTS: There were no differences in segmental retention of either tracer or in mean activity profiles between control subjects and constipated patients. Results in constipated subjects were significantly different from those in controls. The mean half-clearance times of tracer for control subjects were 28.8 h for 67Ga-citrate and 29.9 h for 111In-DTPA in control subjects and 75.0 h for 67Ga-citrate and 70.8 h for 111In-DTPA in constipated patients. CONCLUSION: Oral 67Ga-citrate can be used as a safe alternative to 111In-DTPA for accurate measurement of segmental colonic transit.

Administration, Oral↗
PubMed1998

Nutrition, osteoporosis, and aging.

Loss of bone is an almost universal accompaniment of aging that proceeds at an average rate of 0.5-1% per annum from midlife onwards. There are at least four nutrients involved in this process: calcium, salt, protein, and vitamin D, at least in women. The pathogenesis of osteoporosis in men is more obscure. Calcium is a positive risk factor because calcium requirement rises at the menopause due to an increase in obligatory calcium loss and a small reduction in calcium absorption that persist to the end of life. A metaanalysis of 20 calcium trials shows that this process can generally be arrested by calcium supplementation, although there is some doubt about its effectiveness in the first few years after menopause. Salt is a negative risk factor because it increases obligatory calcium loss; every 100 mmol of sodium takes 1 mmol of calcium out of the body. Restricting salt intake lowers the rate of bone resorption in postmenopausal women. Protein is another negative risk factor; increasing animal protein intake from 40 to 80 g daily increases urine calcium by about 1 mmol/day. Low protein intakes in third world countries may partially protect against osteoporosis. Vitamin D (sometimes called a nutrient and sometimes a hormone) is important because age-related vitamin D deficiency leads to malabsorption of calcium, accelerated bone loss, and increased risk of hip fracture. Vitamin D supplementation has been shown to retard bone loss and reduce hip fracture incidence in elderly women.

Aged↗
PubMed1998

Comparisons of two-, three-, and four-compartment models of body composition analysis in men and women.

This study compared the traditional two-compartment (fat mass or FM; fat free mass or FFM) hydrodensitometric method of body composition measurement, which is based on body density, with three (FM, total body water or TBW, fat free dry mass)- and four (FM, TBW, bone mineral mass or BMM, residual)-compartment models in highly trained men (n = 12), sedentary men (n = 12), highly trained women (n = 12), and sedentary women (n = 12). The means and variances for the relative body fat (%BF) differences between the two- and three-compartment models [2.2 +/- 1.6 (SD) % BF; n = 48] were significantly greater (P </= 0.02) than those between the three- and four-compartment models (0.2 +/- 0.3% BF; n = 48) for all four groups. The three-compartment model is more valid than the two-compartment hydrodensitometric model because it controls for biological variability in TBW, but additional control for interindividual variability in BMM via the four-compartment model achieves little extra accuracy. The combined group (n = 48) exhibited greater (P < 0.001) FFM densities (1.1075 +/- 0.0049 g/cm3) than the hydrodensitometric assumption of 1.1000 g/cm3, which is based on analyses of three male cadavers aged 25, 35, and 46 yr. This was primarily because their FFM hydration (72.4 +/- 1.1%; n = 48) was lower (P </= 0.001) than the hydrodensitometric assumption of 73.72%.

Absorptiometry, Photon↗
PubMed1998

Colour Doppler induced streaming: an indicator of the liquid nature of lesions.

As sound waves traverse tissue, interaction with reflecting or absorbing obstacles results in a transfer of momentum from the wave to the medium. This generates a local force in the direction of propagation. If this occurs in a fluid medium, sufficient pressure may be generated to cause flow--"streaming". Generally, it is difficult to demonstrate this streaming in images using the usual diagnostic B-mode intensities, but the increased intensities in a colour Doppler (or power) region of interest enhance the phenomenon. This allows streaming to be both visualized by the motion of small particles and detected by colour change on the colour Doppler B-mode image. Borders of streaming between the simple grey scale image and the colour region may be easily seen, with retrograde flow in the regions subjected to a lower intensity. This phenomenon has been demonstrated in ocular, scrotal, thyroid, breast, ovarian and inflammatory collections or lesions, confirming the liquid nature, occasionally of fluid which is very echogenic due to contained debris. The technique is recommended as another tool which is available to most general ultrasound departments and will assist in the characterization of tissue.

Cyst Fluid↗
PubMed1997

Relation between postprandial satiation and antral area in normal subjects.

The factors influencing appetite in humans are poorly understood. There is a weak relation between appetite and gastric emptying in normal subjects. Recent studies have shown that fasting and postprandial antral areas increase in patients with functional dyspepsia compared with normal subjects. We evaluated the hypothesis that antral area, and hence antral distention, is a significant determinant of postprandial fullness. Fourteen normal subjects had simultaneous measurements of gastric emptying by scintigraphy and antral area by ultrasound after ingestion of 350 mL 20% glucose. Fullness and hunger were assessed by visual analog scales. Measurements of the gastric-emptying half time (t1/2) by scintigraphy and ultrasound were not significantly different (129.6 +/- 11.8 min compared with 115.6 +/- 11.4 min). Fullness increased (P < 0.001) and hunger decreased (P < 0.001) after the drink. Both fullness and the magnitude of the increase in fullness after the drink were related to antral area (r > 0.56, P < 0.05), the increase in antral area (r > 0.59, P < 0.05), and the scintigraphic content of the distal stomach (r > 0.57, P < 0.05), but not to the ultrasound or scintigraphic t1/2 values. In contrast, hunger and the magnitude of the decrease in hunger after the drink were not related to either antral area, the increase in antral area, or the rate of gastric emptying. We conclude that postprandial fullness, but not hunger, was closely related to antral distention in normal subjects.

Adult↗
PubMed1997

Body composition changes in elite male bodybuilders during preparation for competition.

Anthropometric profiles together with a 4 compartment criterion model of body composition analysis (total body water, bone mineral, fat and residual masses via a combination of deuterium dilution, dual-energy x-ray absorptiometry and hydrodensitometry) were conducted on 3 elite male bodybuilders 10 wk and then 5 d before competition. A mean body mass reduction from 99.70 (Quetelet's Index = 31.6 kg/m2) to 92.79 kg (Quetelet's Index = 29.2 kg/m2) was accompanied by a decline in the sum of 8 skinfold thicknesses (triceps, subscapular, biceps, iliac crest, supraspinale, abdominal, front thigh and medial calf) from 51.1 to 36.7 mm. The 4 compartment body composition model indicated that there were reductions of: percent body fat (%BF) from 9.1 to 5.0%, fat free mass (FFM) from 90.60 to 88.14 kg and fat mass (FM) from 9.10 to 4.65 kg. Sixty-four percent of the 6.91 kg loss in body mass therefore came from the FM. The 2 compartment hydrodensitometric model yielded higher %BFs (initial = 11.2; final = 7.1) than the 4 compartment model (initial = 9.1; final = 5.0) which is theoretically more valid because it controls for biological variability in the percentages of water and bone mineral in the FFM. Nevertheless, both models registered decreases of 4.1%BF.

Absorptiometry, Photon↗
PubMed1996

Regional bone mineral density interrelationships in normal and osteoporotic postmenopausal women.

We describe a prospective study in which bone mineral density (BMD) was measured in total body and regions, proximal femur, lumbar spine, and forearm in 84 apparently normal postmenopausal women with normal spinal radiographs and in 47 women with 1-10 wedged or compressed vertebrae. There was a history of peripheral fracture in 35 of the 84 controls and 30 of the 47 osteoporotics (p < 0.02) but there was no association between vertebral fracture and wrist fracture. At all sites and regions, the differences in BMD between the "normal"and "osteoporotic" women was highly significant and all but "ribs" and "arms" remained significant after correction for menopausal age. In the whole set, and in both subgroups, the coefficients of correlation between sites and regions were all highly significant (p < 0.001). Nonetheless, some sites discriminated better between the two groups than others. Standardized odds ratios (OR) for vertebral fracture versus no-fracture were calculated by logistic regression and expressed as the rise in OR for each standard deviation (SD) fall in bone density. This ratio was greatest (3.4) in "pelvis" and weakest (1.7) in "ribs" but all were statistically significant. Geometric mean regression equations were calculated for all the 78 possible pairs of sites and regions in the 84 normal subjects and the deviations of the osteoporotic women from these normal slopes calculated. In most pairs of sites and regions, the vertebral fracture cases were scattered around the normal group's slope but fell lower down on both axes. The bone deficits in the osteoporotics compared with young normal women ranged from -14% in "head" to -40% in Ward's triangle and the T-scores ranged from -1.9 in "ribs" to -3.9 in the forearm. Sensitivity ranged from 17% in "ribs" to 36.2% in Ward's triangle. Specificity varied between 88 and 94% and the percent correctly classified ranged from 62.6% in "ribs" to 72.5% in Ward's triangle. We conclude that primary postmenopausal osteoporosis affects the entire skeleton but that some sites discriminate better between vertebral fracture and nonfracture cases regardless of whether they represent cortical or trabecular bone.

Absorptiometry, Photon↗
PubMed1996

Vitamin D receptor genotypes are related to bone size and bone density in men.

Three restriction fragment length polymorphisms in the vitamin D receptor gene have been associated with a low bone density in twin and female population studies, but no studies have been conducted exclusively in men. We studied 146 normal men aged 20-83 years. Bone density was measured in the spine, hip, whole body and forearm, and the Bsm polymorphism for the vitamin D receptor was detected by the polymerase chain reaction. Men with genotype BB tended to have a lower bone density at all but one site than the other genotypes. In the men < or = 50 years of age bone density in the forearm was 7% lower in the BB than the Bb and bb groups (P = 0.030) but bone mineral content did not differ between the groups. Bone area was greater in the BB genotype at all sites. This was statistically significant in the forearm (P = 0.026). We conclude that BB genotype is associated with lower bone density in men, which may be due to larger bone size rather than reduced bone mass.

Absorptiometry, Photon↗