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Biomedical subjects

M H Gault

Publications and source records attributed to M H Gault.

At least 91 records · Page 5Linked to original sources
PubMed1980

Comparison of infrared and wet chemical analysis of urinary tract calculi.

Infrared analysis of urinary tract calculi using the system of interpretation of spectra of Oliver and Sweet [1] was compared with qualitative wet chemical analysis. This method of interpretation could be learned quickly and gave reproducible results, but had some limitations. Advantages of the infrared procedure include greater reproducibility. 1-mg sample size, greater sensitivity for oxalate and more uniform sensitivities. Minimum detectable amounts of reference standards varied roughly within 1 order of magnitude, compared with a range of 10(5) for wet chemical procedures. The comparable sensitivity for oxalate and phosphate permits a semi-quantitative approach for infrared. The main problems relate to the detection of magnesium ammonium phosphate and carbonate apatite, and wet chemical tests are recommended in addition, when these compounds are suggested. Calculi from 308 patients were analyzed by infrared. With this system of interpretation of spectra, infrared is considered to be a major advance in methodology for analysis of urinary tract calculi in the clinical laboratory, compared with qualitative wet chemical procedures.

Calcium↗
PubMed1980

Pediatric urolithiasis in the 1970s.

We studied retrospectively 38 children who presented with urolithiasis between 1970 and 1977. The sex ratio was 1:1 and the mean age was 9.4 years. A positive family history was found in 36 per cent. Urinary tract abnormalities predisposing to infective urolithiasis was found in 7 children (18 per cent) but required voiding cystography for detection in 5. Hypercalcemia was found in 3 of 32 (8 per cent), while 28 of the 38 patients (74 per cent) had idiopathic urolithiasis. Idiopathic hypercalciuria was found in 5 of 13 patients (38 per cent) with idiopathic urolithiasis. Investigation of urolithiasis in children should include voiding cystography and measurement of urine calcium, as well as oxalate and uric acid, under home diet conditions.

Adolescent↗
PubMed1980

Loading dose of digoxin in renal failure.

1 Twenty-two dialysis dependent patients received an intravenous loading dose of digoxin of 10 microgram/kg and the mean +/- s.d. serum digoxin concentration 24 h later was 1.5 ng/ml +/- 0.4 (range 0.8--2.1 ng/ml). No evidence of toxicity was observed. 2 The average apparent volume of distribution of digoxin in dialysis dependent patients was found to be reduced by about one third compared with that reported for individuals with normal renal function, but there was great variation. 3 An appropriate intravenous loading dose of digoxin in most patients with advanced renal failure is 10 microgram/kg.

Acute Kidney Injury↗
PubMed1979

Biotransformation and elimination of digoxin with normal and minimal renal function.

Six subjects with normal renal function (NRF) and 6 patients with minimal renal function (MRF) on 3 times weekly hemodialysis received 150 muCi3H-digoxin-12 alpha orally. Serial urine collections were made for five days or more. Digoxin and metabolites were separated using diethylaminoethyl Sephadex LH-20 column chromatography. Mean cumulative percentages of the ingested radioactivity excreted over five days in NRF and MRF groups were: digoin, 54.5% and 14.7%; bis-digitoxoside of digoxigenin, 2.0% and 0.59%; mono-digitoxoside, 0.8% and 0.19%; digoxigenin, 0.25% and 0.03%; and dihydrodigoxin, 0.3% and 0.03%. Half-lives based on the mean rates of disappearance from urine comparing NRF and MRF groups were: for digoxin 40 hr and 120 hr; for bis-digitoxoside, 11.5 hr and 46 hr; for mono-digitoxoside, 8.5 hr and 12 hr; for digoxigenin, 2 hr and 7.5 hr; and for dihydrodigoxin, 1.2 hr and 7.0 hr. Considering the relationships of the five-day cumulative excretion and half-lives of digoxin and metabolites in the NRF and MRF groups, it appears unlikely that there is a major alteration in the biotransformation of digoxin in advanced renal failure when there appears to be a shift from renal to slower biliary excretion.

Adult↗
PubMed1978

Radiation nephritis following combined abdominal radiation and chemotherapy (bleomycin-vinblastine).

A 29-year-old man presented with acute glomerulonephritis five weeks following completion of combined chemotherapy (bleomycin-vinblastine) and abdominal radiation for testicular carcinoma. There was no evidence for a post-infectious cause or a systemic collagen disorder. The renal biopsy showed changes consistent with radiation nephritis. The combined radiation and chemotherapy may have, by additive or synergistic action, caused the early appearance of radiation nephritis.

Adult↗
PubMed1977

Hydrolysis of digoxin by acid.

Predictable hydrolysis of [3H]digoxin-12alpha occurred in vitro with incubation in HCl or gastric juice. Hydrolysis varied with pH, time, temperature and agitation. Digoxin, the bis- and mono-digitoxosides of digoxigenin and digoxigenin were separated by silica gel thin-layer chromatography using chloroform-ethyl acetate-glacial acetic acid (25:25:1 v/v) and were quantitated by liquid scintillation spectrometry. Hydrolysis with incubation at 37 degrees and pH 3 for 90 min was minimal, but increased with increasing acidity until greater than 70% was hydrolysed at pH 1-2 after 30 min and greater than 96% after 90 min incubation. At pH 0-9, 87% was hydrolysed after 30 min. In vitro hydrolysis in gastric fluid was slightly less than in HCl at the same pH. A volunteer was given 150 muCi[3H]digoxin-12alpha by nasogastric tube during a pentagastrin infusion when gastric pH was 0-94. He remained on his left side and samples were aspirated at intervals and immediately neutralized. Ethanol-chloroform 50-50 (v/v) extracts of the gastric fluid aspirated after 90 min and of all the urine specimens collected for 5 days were applied to a DEAE Sephadex LH-20 column. The radioactivity appeared in a single peak as digoxigenin in the 90 min gastric aspirate and in all urine specimens. Extensive intragastric hydrolysis of digoxin may occur under conditions of maximum acid output.

Adult↗