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Biomedical subjects

K F Szaz

Publications and source records attributed to K F Szaz.

15 recordsLinked to original sources
PubMed1992

Glycogen storage: illusions of easy weight loss, excessive weight regain, and distortions in estimates of body composition.

Glycogen is stored in the liver, muscles, and fat cells in hydrated form (three to four parts water) associated with potassium (0.45 mmol K/g glycogen). Total body potassium (TBK) changes early in very-low-calorie diets (VLCDs) primarily reflect glycogen storage. Potassium released from glycogen can distort estimates of body composition during dieting. TBK changes due to glycogen mobilization were measured in 11 subjects after 4 d dieting with a VLCD. The influence of water-laden glycogen on weight fluctuations during the dieting process, the exaggerated regain if carbohydrate loading occurs, and the implications for weight control programs and overestimation of nitrogen losses with dieting are discussed.

Body Composition↗
PubMed1990

Non-invasive method for delivery of tracer substances or small quantities of other materials to the colon.

A miniature osmotic pump has been developed (Osmet) with ALZA, Palo Alto, USA, which can be swallowed, will pass through the stomach and small intestine and then deliver its contents (240 microliters) over eight hours in the large bowel. In vitro studies showed the pumps started to discharge after four to five hours and emptied at a reasonably constant rate of 20.4 microliters/h from 9-16 h (9.6%/h). In vivo studies using gamma-scintigraphy in seven healthy subjects show that the pumps left the fasting stomach at 1.2 h (range 0-3) and arrived in the caecum by 6.4 h (range 5-9). Mean start-up time was 5.3 (0.2) h and the rate of discharge was 15.9 microliters/h for pumps studied from 6-12 h and 17.2 microliters/h for those studied from 10-20 h. This device is simple, safe and effective for the delivery of tracer substances to the caecum and colon without interfering with patients' normal lifestyle.

Adult↗
PubMed1987

The permeability of detachable latex rubber balloons. An in vitro study.

Previous studies have shown that a silicone rubber balloon filled with a hyperosmolar solution of contrast medium expands and may rupture because the wall acts as a semipermeable membrane. The deflation of latex rubber balloons in vivo has been attributed to the same cause. The authors investigated the behavior of latex rubber balloons filled with metrizamide solutions ranging from hyperosmolar to hypo-osmolar relative to plasma. When balloons were immersed in plasma, tritiated water passed bidirectionally through the wall at a rate unrelated to the concentration or volume of the contrast medium in the balloon. There was no exchange of sodium ions across the wall, and the osmolality of the metrizamide did not change over a period of up to six weeks. The authors conclude that deflation of a latex rubber balloon during the first few hours or days is not due to osmosis.

Animals↗
PubMed1987

Radionuclide tests for the assessment of intestinal permeability.

14C labelled-D-mannitol and aquo (ethylene-diaminetriacetoacetic acid) 51chromium (III) (51Cr EDTA) have been evaluated as markers of intestinal permeability in twenty-four healthy control subjects, sixteen patients with recently diagnosed coeliac disease and twenty subjects with coeliac disease in remission on a gluten-free diet. The percentage excretion of 14C mannitol in urine collected for 6 h was significantly less in patients with coeliac disease (mean 6.7%) than controls (mean 13.5%). Conversely the excretion of 51Cr EDTA was significantly greater in patients with coeliac disease (mean 1.23%) compared with controls (mean 0.28%). The mean ratio of the percentage excretion of 51Cr to the percentage excretion of 14C was 0.29 in patients with untreated coeliac disease compared with 0.023 for healthy control subjects (P less than 0.001). Patients with untreated coeliac disease were clearly separated from control subjects by use of the 51Cr EDTA: 14C mannitol ratio but not by the excretion of independent markers.

Adult↗
PubMed1984

Measurement of regional lower limb blood flow in normal humans by inhalation of 133Xe.

A non-invasive method of measuring regional calf blood flow after inhalation of 133Xe has been investigated. The mean blood flow at rest was 3.3 ml X min-1 X 100 g tissue-1 by the 133Xe method and 3.5 ml X min-1 X 100 g tissue-1 by plethysmography. There was a significant correlation r = 0.88, P less than 0.001. During exercise the mean blood flow in the anterior tibial compartment increased from 3.4 to 10.9 ml X min-1 X 100 g tissue-1 in ten cases and in the posterior compartment from 3.3 to 7.1 ml X min-1 X 100 g tissue-1 in seven cases as measured by the 133Xe technique. The inhalation method seems to be an accurate, reliable and non-invasive method for measuring tissue blood flow in the human calf at rest and during exercise.

Adult↗
PubMed1984

Measurement of skin and total blood flow to the rabbit lower limb by washout of freely diffusible radioactive tracers introduced intra-arterially.

Good agreement was obtained when measuring total (capillary) blood flow in 9 rabbit thighs using two different techniques. The 133Xenon washout technique yielded a mean value of 8.0 cm3 X min-1 X 100 g tissue-1 whilst the microsphere technique gave a mean value of 7.8 cm3 X min-1 X 100 g tissue-1. There was a significant correlation (r = 0.83, p less than 0.006). In a further 14 rabbit thighs an attempt was made to measure skin blood flow by washout of 85Kr and to compare it with the microsphere technique. 133Xe promises to be a useful tracer for measuring lower limb flow when introduced intra-arterially. Because 85Kr tends to underestimate skin blood flow, and because of problems of diffusion of the tracer between compartments, which are discussed, this tracer is not satisfactory as a technique for measuring skin blood flow.

Animals↗