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Biomedical subjects

R Hesp

Publications and source records attributed to R Hesp.

At least 73 records · Page 4Linked to original sources
PubMed1982

Rates of new bone formation in patients with crush fracture osteoporosis.

1. Calcium balances and formation rates of new bone measured with an improved tracer technique using 85Sr have been determined simultaneously in 21 patients with idiopathic osteoporosis and vertebral crush fractures. 2. A weak positive association was found between calcium balance and the kinetically measured calcium accretion rate, which is the sum of the true rate of bone formation and various long-term exchange processes. 3. The more negative balances were associated with significantly greater early loss of tracer taken up into bone by 'accretion', so that long-term (greater than 200 day) uptake was reduced. 4. This indicates that patients actively losing bone mineral have lower true rates of bone formation and higher rates of long-term exchange than their fellow patients who are more nearly in calcium equilibrium. 5. No statistically significant association was found between measured rates of bone resorption and calcium balance.

Aged↗
PubMed1982

Risk factors for fractured neck of femur in the elderly.

During a 15-month period, 47 elderly female patients admitted to hospital with a fractured neck of femur were studied immediately prior to discharge, in comparison with 34 elderly female control patients undergoing elective surgery who had been admitted over the same period to the same orthopaedic wards. The principal differences between the two populations were that the fracture patients had a lower forearm trabecular bone density, with lower bodyweight (both lower muscle mass and lower fat content), increased body sway, worse eyesight and reduced mental acuity. The serum biochemistry of the two groups was almost indistinguishable except that the fracture patients tended to have slightly lower concentrations of proteins. There was no evidence to implicate dietary vitamin D deficiency, osteomalacia, oestrogen deficiency or alcoholism in the aetiology of the fracture, nor was there evidence to suggest alterations in endocrine function with respect to cacitonin or parathyroid hormone.

Aged↗
PubMed1982

Potassium supplements during long-term thiazide therapy for essential hypertension.

Increasing doses of a slow-release potassium supplement were given to nine hypertensive patients previously treated for at least 18 months with bendrofluazide 10 mg daily. Serum potassium and total body potassium (TBK) were measured after 2 months on each dose. No significant increase in serum potassium or TBK occurred over a 6 month period of supplementation using doses commonly prescribed in clinical practice.

Adult↗
PubMed1982

Bone rarefaction and crush fractures in juvenile chronic arthritis.

Seventy children with juvenile chronic arthritis have had measurements of cortical and trabecular bone density in one or both radii. In 7 children with unilateral disease of one wrist, there was a substantial reduction in growth on the affected side. Trabecular bone density in the distal radius was reduced in the main group of 63 patients compared with controls, and this deficit was appreciably worse if the wrist was clinically affected by disease or if the child was being treated with steroids. Cortical bone density in the midshaft was less affected. Crush fractures of the spine were associated with more prolonged periods of bed rest, steroid therapy, radial trabecular bone density more than 2 standard deviations below normal, and subnormal 25-hydroxycholecalciferol concentrations in the serum. Since steroid therapy is often mandatory the main therapeutic implications are that the more severely affected child often needs vitamin D supplementation in "physiological" dosage, and that early mobilisation and reduction of steroid dosage should be constant aims.

25-Hydroxyvitamin D 2↗
PubMed1982

Selenium 75-selenofolate metabolism and radiation dosimetry.

Following the oral administration of 75Se-selenofolate in two normal healthy volunteers, retention was measured by whole body counting, and distribution throughout the body was determined with a hybrid scanner. Approximately 65% of the dose was absorbed from the GI tract. The metabolic data obtained from this study was used to calculate the integrated radiation dose to the liver, and the effective dose equivalent.

Absorption↗
PubMed1982

Long-term treatment of osteoporosis with 24,25 dihydroxycholecalciferol.

Five patients with involutional osteoporosis were treated with 24,25 dihydroxycholecalciferol (24,25-(OH)2D3) for 6 months, in doses sufficient to double plasma levels at that time. Dietary calcium absorption transiently improved by nearly 2 mmol Ca per day at 2 weeks, but this effect was lost by 6 months. The calcium and phosphate balances followed the trends in calcium absorption. Only twenty-five dihydroxyvitamin D levels changed little. Histomorphometric and kinetic indices of new bone formation and bone blood flow remained stable but there was an increase in urine hydroxyproline at 6 months, which was of borderline statistical significance. Treatment at this dosage of 24,25(OH)2D3, which increased plasma levels within the physiological range, conferred no measurable long-term benefit on our patients. Larger doses, or combination therapy, may warrant further clinical evaluation in osteoporosis.

24,25-Dihydroxyvitamin D 3↗
PubMed1982

Prediction of energy requirements of obese patients after massive weight loss.

A regression analysis was made of resting metabolic rate on weight and body composition in 140 women with varying degrees of obesity. In 19 severely obese women before weight loss, average resting metabolic rate was 290 ml O2/min, or 4 per cent higher than predicted from the regression equation. After losing 30 kg in one year the average metabolic rate of this group was 234 ml O2/min, 1 per cent higher than that predicted for their reduced weight. Women whose metabolic rate was high or low relative to prediction before weight loss tended to maintain this status after weight loss (P less than 0.05). There is a close relation between resting metabolic rate and total energy expenditure. We conclude that there is a reduction in energy requirements for weight maintenance after massive weight loss, but the requirements of obese patients after weight loss are similar to those of people of comparable weight who have not reduced.

Adolescent↗
PubMed1980

Deficit of trabecular and cortical bone in elderly women with fracture of the femoral neck.

1. The mean attenuation coefficients of trabecular and cortical bone in the radius were measured in 32 female patients with fractured proximal femur, and in 28 age-matched female controls, with a special-purpose computed tomography-scanner. 2. The largest difference between the two groups was in the mean attenuation coefficients for trabecular bone in the distal radius. The mean value for fracture patients (0.53 cm-1) was significantly lower (P < 0.02) than the mean value for the controls (0.62 cm-1). These results are consistent with the view that a loss of trabecular bone predisposes to fractures of the proximal femur.

Aged↗
PubMed1980

Methods and problems in the measurement of body water and electrolyte pools with radionuclide tracers.

With the possible exception of ECF, body electrolyte spaces and pools can be measured with fair accuracy and are useful in their proper experimental context. The use of improved tracer techniques and mathematical analysis to study transfer rates between pools and the physiological factors which influence these rates offer a promising means of further progress in this field.

Body Fluid Compartments↗
PubMed1979

A comparison of chromium sesquioxide and [51Cr]chromic chloride as inert markers in calcium balance studies.

1. Chromium sesquioxide (Cr2O3; 1.5 g/day) and [51Cr]chromic chloride [51CrCl3 (0.3 muCi/day)] were compared as continuously administered non-absorbed markers for the correction of faecal recoveries in 14 calcium balance studies each lasting at least 18 days. 2. The mean recoveries of each, 98.4% for Cr2O3 and 101.9% for 51CrCl3, were not significantly different from 100%. 3. The two markers reduced the uncertainity in a typical 3 x 6 day calcium balance study to a similar extent (SD = 1.4 mmol/day for Cr2O3 and SD = 1.5 mmol/day for 51CrCl3. 4. 51CrCl3 is a convenient and satisfactorily alternative to Cr2O3 when the laboratory hazards associated with estimating the latter cannot easily be eliminated.

Calcium↗
PubMed1979

Fractured neck of femur in the elderly: an attempt to identify patients at risk.

1. During a 15-month period, 110 elderly patients admitted with fractured neck of femur were studied in comparison with 72 elderly control patients undergoing elective surgery admitted over the same period to the same orthopaedic wards. 2. A striking finding was the marked similarity of all variables measured in the fracture and control groups. The principal differences between the two populations were that the fracture patients had a lower mean forearm bone mineral content, and that their serum concentrations of albumin, globulin and phosphate were reduced. 3. Neither measurements of radioisotopic calcium absorption, nor those of the serum concentrations of calcium, 25-hydroxy-vitamin D3 nor alkaline phosphatase provided satisfactory discrimination between the groups. 4. Several indices were devised, based on linear combinations of the test results obtained, in an attempt to predict the liability to future fractures of patients being considered for prophylactic therapy with oestrogens or other drugs. However, further work is required to define an index of improved predictive power and to evaluate it prospectively.

Aged↗
PubMed1979

A new method for measuring the body density of obese adults.

1. A new apparatus is described with which it is possible to measure the volume (and hence density) of obese patients without requiring them to immerse totally in water. Replicate measurements of subjects with 6, 23 and 38 kg body fat had a standard deviation not greater than 0.3 kg fat. 2. In nineteen obese women body fat was measured by density, total body water, and total body potassium at the beginning, and again at the end, of a period of 3--4 weeks on a reducing diet, during which they lost 5.43 (SD 1.83) kg in weight. The composition of weight loss was also estimated both by energy balance and nitrogen balance during the interval between the two measurements of body composition. 3. The estimates of fat content of the ninetten women at the start of the balance period were 45.63 (SD 14.50) kg by density, 48.07 (SD 13.88) kg by K and 47.09 (SD 13.85) kg by water. The correlation coefficient between the density and K estimate was 0.949, and for the density and water estimate it was 0.971. 4. It is concluded that measurement of density by the new method provides a convenient method for estimating body fatness, and change in fat content, which compares favourably with estimates based on total body water or total body K. However, these methods cannot be used to provide an accurate estimate of the composition of a small weight loss in an individual since deviations up to 4 kg fat occur between fat loss based on change in density and those based on the more reliable (but more tedious) energy balance method.

Adipose Tissue↗
PubMed1979

Resting metabolic rate, weight, surface area and body composition in obese women.

Resting metabolic rate was measured in 22 women with varying degrees of obesity. Body composition was estimated from total body potassium and from total body water, and creatinine excretion in urine was measured over a period of three weeks while the patients were on a creatinine and creatine-free reducing diet. Resting metabolic rate was highly significantly correlated with body weight, surface area, creatinine excretion and lean body mass calculated either from potassium or water measurements (P less than 0.001). Correlation with adipose tissue was less strong, and when multiple regression of both fat and lean on metabolic rate was performed, the relationship was seen to depend mostly on the mass of lean rather than adipose tissue. In obese people the water content of fat-free tissue is greater than that in normal subjects, so it is not valid to assume that fat content can be calculated accurately from a measurement of total body water.

Adipose Tissue↗
PubMed1978

The feasibility of using a liquid-filled Cerenkov counter of gamma-ray counting of large samples.

The feasibility of detecting gamma rays with energies below 1.5 MeV by means of a large-volume liquid-filled Cerenkov counter has been examined, together with the characteristics and limitations of an experimental counter. Various liquids (water, glycerol, sodium iodide solution; and glycerol plus a wavelength shifter) were investigated as possible Cerenkov media. A rectangular counter containing 1.2 liters of the latter medium could detect 10 nCi of 58Co or 59Fe at 10 cm in a counting time of 1000 s.

Gamma Rays↗