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Biomedical subjects

J E Scott

Publications and source records attributed to J E Scott.

At least 19 recordsLinked to original sources
PubMed1979

A reaction for the simple sensitive fluorimetric assay of heparin and 2-amino sugars.

1. 3,5-Diaminobenzoic acid reacted rapidly with the product from HNO(2) deamination of heparin, heparan sulphate and 2-amino-2-deoxyhexoses under very mild conditions (pH3.0 and 37 degrees C) to give stable fluorescent derivatives. 2. The fluorescence yield was rectilinearly related to the concentration of heparin etc. Less than 0.1mug of 2-amino-2-deoxyhexose was easily measurable in standard cuvettes. 3. The deamination products of glucosamine and (particularly) galactosamine were labile in the HNO(2) reagent, with half-lives of 20-40min at room temperature. At 0 degrees C they were much more stable. The analogous product from heparin was not so labile. 4. Under the standard conditions, and at room temperature, relative fluorescence yields (d-glucosamine=1.0) were: d-galactosamine, 0.75; d-gulosamine, 0.38; d-mannosamine, approx. 0.20. 5. Neutral sugars, chondroitin sulphates, DNA and N-acetylneuraminic acids did not react, nor did N-acetylamino sugars or non-deaminated hexosamines. 6. It is suggested that the Dische-Borenfreund [Dische & Borenfreund (1950) J. Biol. Chem.184, 517-522] indole method, the Kissane-Robins [Kissane & Robins (1962) J. Biol. Chem.233, 184-188] DNA assay and the proposed amino sugar method are all examples of simple aldehyde reactions. The specificity of the proposed method is considerably greater than that of the Dische-Borenfreund procedure, partly because of the much milder reaction conditions. 7. The proposed method is very reproducible, about 50-100 times as sensitive as the Elson-Morgan reaction, and 10-50 times as sensitive as the Dische-Borenfreund procedures. It is also convenient; acid hydrolysates of amino sugar-containing compounds can be directly neutralized with sodium acetate solution.

Amino Sugars↗
PubMed1979

1H nuclear-magnetic-resonance spectra of the methyl group of the acetamido moiety and the structure of acid glycosaminoglycans in solution.

The 1H resonances of the methyl group in the acetamido moiety of several types of glycosaminoglycans are reported at 300 MHz in 2H2O. Dermatan sulphates with various L-iduronate/D-glucuronate ratios are compared with chrondroitin sulphates with various contents and positions of substitution of sulphate esters. Hyaluronate oligomers are compared with 2-acetamido-2-deoxy-D-glucose, and with heparan sulphate and keratan sulphate. The major determinant of the chemical shift of the acetamido methyl resonance is the closeness of approach between carboxy groups and the acetamido group, in agreement with chemical evidence based on periodate-oxidation kinetics.

Acetamides↗
PubMed1979

Antibiotic prophylaxis in total hip replacement.

A controlled prospective trial to compare the efficacy of the antibiotics cephaloridine and flucloxacillin in preventing infection after total hip replacement was conducted at three hospitals. The antibiotic regimens began before surgery, cephaloridine being continued for 12 hours and flucloxacillin for 14 days afterwards. Over an 18-month period 297 patients undergoing a total of 310 hip replacements were entered into the trial and randomly allocated to one of the regimens. The follow-up period ranged from one to two and a half years. All operations were performed in conventional operating theatres; at two of the hospitals these were also used by various other surgical disciplines. Four patients developed deep infection, two having received the cephaloridine and two the flucloxacillin regimen. The overall rate of deep infection was therefore 1.3%. Thus three doses of cephaloridine proved to be as effective as a two-week regimen of flucloxacillin. Giving a prophylactic systemic antibiotic reduced the incidence of infection to a level comparable with that obtained in ultra-clean-air operating enclosures.

Aged↗
PubMed1979

Axillary artery occlusion with erect dislocation of the shoulder.

Occlusion of the axillary artery occurred in a man with erect dislocation (luxatio erecta) of the shoulder. This combination of injuries has not previously been reported. The arterial injury was demonstrated by arteriography and repaired by a vein graft. There was an associated fracture of the greater tuberosity of the humerus, which required open reduction and internal fixation.

Adult↗
PubMed1979

The "small patella" syndrome.

Twelve closely related members of one family were found to have small or absent patellae. Seven of these patients also had abnormalities of the pelvic girdle and upper femora. There was a resemblance to the nail--patella syndrome in the patellar abnormalities but not in the associated conditions, and it would therefore appear that the syndrome described is a new variety of congenital abnormality of the knee.

Adolescent↗
PubMed1979

Circadian rhythms and the urinary excretion of acid glycosaminoglycans in normal human adults.

Urine from normal human adults (11 males, 4 females) was collected for 24 hours in four-hour samples, commencing at 08.00 hours. The urine volume, and concentrations of chondroitin sulfate, heparan sulfate, cetylpyridinium turbidity, and creatinine were measured on every sample. Concentrations and total output of glycosaminoglycans were significantly higher in male urine than in female urine. Chondroitin sulfate total output/four hours showed a significant negative correlation with creatinine concentration in males, but not in females. A testicular hyaluronidase is implicated. No such correlation was observed for heparan sulfate. Glycosaminoglycans are filtered into the urine. Plasma clearances are very low. Heparan sulfate is excreted with a circadian rhythm, as is glycosaminoglycan assayed by cetyl pyridinium turbidity. Peak excretions are at 06.00 and 10.00 hours respectively. Chondroitin sulfate excretion is not rhythmic in the male, perhaps because hyaluronidase activity in the urine complicates the assay. A rhythm may be present in the female.

Adult↗
PubMed1978

Periodate oxidation and the shapes of glycosaminoglycuronans in solution.

1. It is proposed that periodate oxidation of glycol groups in the repeating units of polysaccharide molecules can be used to probe differences in polymer shapes in solution. 2. Measurement of second-order rate constants (k2) of periodate-glycol reactions may be compared between polymers and relevant monomers, to assess perturbations due to polymer configuration. 3. Factors effecting the measurement and interpretation of k2 are discussed. Over-oxidation, free-radical side reactions, end-group effects, Donnan equilibria and polymer (or molecular-weight) effects are relevant, but their importance is either small or can be minimized in practice. 4. A small group of glycosaminoglycuronans (chondroitin 4- and 6-sulphates and hyaluronate) are oxidized 50--100 times more slowly than three other glycosaminoglycuronans of similar composition, relevant monomers or three homopolyuronides. 5. A stable configuration in solution is postulated for the periodate-resistant polymers, involving carboxylate, acetamido and hydroxy groups in hydrogen-bonded sequences on alternate sides of the molecule. The more easily oxidizable polyuronides are unable to form this configuration. 6. The effect of temperature on the postulated configuration is investigated through the Arrhenius plot of k2, measured to hyaluronate, chondroitin 6-sulphate and methyl 4-O-methyl-alpha-D-glucopyranoside. Probable transitions at high (around 90 degrees C) temperatures were observed for both polymers, with an additional transition at about 37 degrees C in the case of hyaluronate. 7. L-Iduronic acid can take up different conformations depending on the polymer environment.

Chemical Phenomena↗
PubMed1978

Demineralization in organic solvents by alkylammonium salts of ethylenediaminetetra-acetic acid.

1. Insoluble salts of alklaine earth metals (e. g. calcium phosphate) dissolve in non-aqueous solvents containing EDTA salts of organic cations (e.g. tetraethylammonium). 2. Bone is efficiently demineralized in ethanolic trimethylammonium EDTA. Retention in the matrix of water-soluble materials (e.g. proteoglycan) is much better than in standard aqueous EDTA demineralization procedures.

Animals↗
PubMed1978

A quantitative study of the effects of acetylsalicylic acid on spermatogenesis and organs of the rat.

Although the occurrence of prostaglandins in the male reproductive organs is consistent, their physiological role in fertility and reproduction is not known. The influence of acetylsalicylic acid, an inhibitor of prostaglandin synthesis, on the male reproductive tract was investigated in Sprague-Dawley rats of proven fertility. Acetylsalicylic acid dissolved in phosphate buffer was administered once a day at two dosages (300 mg/kg body weight and 150 mg/kg body weight) over a period of 12 days and a period of 6 days. The animals were killed 24 hours after the final treatment and the testes, epididymides, ductus deferens, seminal vesicles, kidneys, and adrenal glands were removed and placed in Bouin's solution. Subsequently, the tissues were cleaned and weighed and the testes were prepared for quantitative study under the light microscope. Organ weights were not significantly altered in the animals that were treated with acetylsalicylic acid. Cell counts indicated that there was a significant increase in the mean number of preleptotene spermatocytes and spermatids in those animals treated with the drug for 6 days at a dose of 150 mg/kg body weight. Treatment at the same dosage for a period of 12 days produced a significant decrease in the mean numbers of preleptotene and pachytene spermatocytes and spermatids. The mean diameter of the seminiferous tubules was also significantly decreased in the latter group of animals. In the group of animals treated with ASA for 12 days at a dose of 300 mg/kg body weight the mean diameter of the seminiferous tubules was significantly increased. No clear conclusion as to the effect of the drug on spermatogenesis or the various organs could be drawn.

Animals↗
PubMed1977

The management of ureteric reflux in children.

A series of 262 children suffering from vesico-ureteric reflux is presented. Nearly all presented with a urinary tract infection and the age at onset of symptoms was predominantly in the pre-school years. The reflux was not diagnosed in the majority until after the children started attending school. Over one-third had symptoms for more than half their lives before reflux was diagnosed. The incidence of hypertension and renal insufficiency in the series were 4% and 7-8% respectively. Nearly 60% of the children were selected by defined criteria for operation as their initial treatment. The remainder were treated conservatively in the first instance but 30% of these subsequently required operation. Reflux was eliminated in 96.3% of the children at the first operation and 5.5% developed postoperative ureteric dilatation, none of them permanently. Reflux disappeared spontaneously in two-thirds of the children treated conservatively but took more than 3 years in 46%. Infection recurred in 24% of children treated by operation and in 29% treated conservatively. The incidence with which reflux disappeared spontaneously in the children treated conservatively was related to time, not to the infection recurrence rate.

Acute Kidney Injury↗
PubMed1977

1,25-dihydroxycholecalciferol in renal osteodystrophy. Epiphysiolysis--anticonvulsant therapy.

Three children with azotaemic renal osteodystrophy were treated with 1,25-dihydroxycholecalciferol (1,25(OH)2D3). All showed clinical, biochemical, and radiological improvement within 6 months of starting treatment. There were no complications. The dose of 1,25(OH)2D3 required was 0-5 microgram per day for 2 children aged 22 and 30 months, and 2 microgram per day for a 15-year-old boy. 2 of the patients were receiving phenobarbitone and phenytoin and in one of them prior treatment with dihydrotachysterol 0-5 mg daily and 6 microgram 1alpha-hydroxycholecalciferol (1alphaOHD3) daily had failed to induce improvement. In one patient, in whom serial iliac bone samples were available, 2 microgram 1,25(OH)2D3 resulted in histological improvement in previously severe osteomalacia. 1,25(OH)2D3 appears to be an effective and safe drug in the treatment of uraemic osteodystrophy.

Adolescent↗
PubMed1976

Septic arthritis in association with primary lymphoedema.

The association between b-haemolytic streptococcal arthritis of the knee and primary lymphoedema is reported. This condition appears to resolve slowly using conventional methods of treatment, in the form of immobilisation and antibiotic therapy. However, the penetration of penicillin into the joint in these two patients was adequate, suggesting that there is no place for the intra-articular injection of antibiotic in the treatment of this condition.

Aged↗