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Biomedical subjects

G R Williams

Publications and source records attributed to G R Williams.

At least 145 records · Page 8Linked to original sources
PubMed1979

Internal vascular access for hemodialysis in children weighing less than fifteen kilograms.

An arteroarterial femoral graft using expanded polytetrafluoroethylene is described which has been successfully for vascular access in young children having small peripheral vessels. This graft allows high flow and favorable patency for dialysis without the complications of arteriovenous shunting or the risks associated with an external hemodialysis device. This graft has been used successfully for outpatient dialysis in children weighing as little as 9 kg and may be a useful adjunct in long-term dialysis of patients for whom more conventional means of vascular access are not acceptable.

Blood Vessel Prosthesis↗
PubMed1978

A clinical evaluation of the surgical treatment of anorectal malformations (imperforate anus).

The surgical correction of anorectal malformations remains a serious problem despite their relatively frequent occurrence. Our surgical experience with 90 patients, seen in the past ten years, includes abdominal-perineal or sacro-abdominal-perineal repair in 28 patients, complete perineal anoplasty in 13 patients, and "cut-back" perineal anoplasty in 38 patients. Secondary surgical procedures for "fecal reservoir syndrome" (seven patients), revision for stricture (11 patients) and excision of redundant mucous membrane (ten patients). The observations made from this clinical study are: 1) The importance of thorough urological and neurological evaluation of "high" abnormalities and the value of the cremasteric and bulbocavernosus reflexes as indicators of sacral innervation. 2) Increasing satisfaction with the "cut-back" anoplasty as a definitive procedure or as a temporary stage in low recto-vaginal or recto-vestibular fistulas. The technique for the "cut-back" is improved by the use of Burow's triangles and the use of nonabsorbable sutures. 3) The advisability of the complete perineal anoplasty with posterior positioning of the anus and construction of a perineal body in patients with low recto-vaginal and recto-vestibular fistulas. 4) A concern over the functional capacity of the distal bowel segment in high abnormalities. This is emphasized by the experience with six secondary resections of the rectosigmoid or left colon for "fecal reservoir syndrome." 5) Heartening results with secondary operations for stricture and redundant mucous membrane which suggest the desirability of an earlier surgical approach to these complications.

Anus, Imperforate↗
PubMed1977

The reactivity to N-ethyl maleimide of the subunits of cytochrome oxidase.

Beef heart cytochrome oxidase (EC 1.9.3.1) prepared in this laboratory consistently presents 10 Coomassie blue staining zones on SDS-polyacrylamide gel electrophoresis. At pH 7.0 only two of these polypeptides (III and VIa) are labelled by radioactive N-ethyl maleimide (NEM). The labelling of VIa is variable and correlates with activity of particular oxidase preparations. When cytochrome oxidase is isolated from alkylated membranes, either mitochrondria or electron transport particles, polypeptide VIa is found not to be labelled; polypeptide III is more strongly labelled than when isolated oxidase is alkylated, and label now appears in polypeptide I which is not alkylated upon treatment of isolated oxidase with NEM.

Animals↗
PubMed1976

Mitochondria with impaired phosphate transport: 32P uptake studies.

Rat liver mitochondria which have been exposed to 0.15 M NaC1 at 35 degrees C for 15 min subsequently take up 32Pi from an external medium only to about 5% of the extent of uptake by control mitochondria. The volume into which 32Pi distributes in a pellet of such "aged" mitochondia is less than that available to 3H2O but is greater than that available to [3H]sucrose. Mitochondria treated in this manner cannot therefore accumulate Pi although limited penetration of the inner membrane can occur. These results confirm earlier findings by indirect methods (Williams, G. R. & Orr, J. L.: Dynamics of energy-transducing membranes (Ernster, L., Estabrook, R. W. & Slater, E. C., eds), Elsevier Scientific Publishing Company, Amsterdam, Netherlands, pp. 497-508 (1974).

Animals↗
PubMed1975

Significance of serum amylase level in evaluating pancreatic trauma.

A series of fifty-one patients who underwent exploratory laparotomy for blunt abdominal trauma is reviewed. Attempts to correlate preoperative serum amylase levels with pancreatic injury were unsuccessful. We could find no statistically significant correlation between elevated serum amylase and pancreatic injury. The accuracy of the test improved somewhat with markedly abnormal serum amylase levels (greater than 300 Somogyi units/100 ml), but even at these levels the correlation was not significant. One must conclude that there is no correlation between elevated serum amylase and pancreatic injury in blunt abdominal trauma. Decisions as to the advisability of operation in patients with such trauma should therefore be based on other parameters.

Abdominal Injuries↗
PubMed1975

Hepatic portoenterostomy: an assessment of its value in the treatment of biliary atresia.

A series of 12 infants undergoing hepatic portoenterostomy for incorrectable-type biliary atresia is reviewed. There has been no evidence of a sustained postoperative increase in bile excretion or improvement in biliary cirrhosis in any patient. Survival statistics for the group as a whole are poor with a mean postop survival time of 11 months and a mean total survival time of 15.3 months. These survival times are worse than that previously reported for infants with untreated biliary atresia. Our disappointing results with hepatic portoenterostomy raise doubts concerning its value in the treatment of biliary atresia.

Biliary Tract↗
PubMed1975

The orientation of cytochrome c oxidase in coupled phospholipid membrane vesicles--a spin-label study.

Cytochrome oxidase, an enzyme containing six different subunits, has been shown to span the inner mitochrondrial membrane. The arrangement of the subunits within the membrane is unknown. Wh have specifically labeled the 25 000 molecular weight subunit with a spin-label derivative of N-ethylmaleimide, 3-maleimido-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (NEM-SL(5)). NEM-SL(5)-lebeled cytochrome oxidase can be incorporated into phospholipid membranes to form coupled vesicles of the Hinkle, Kim & Racker ((1972) Jriol. Chem; 247, 1338-1399) type. The resonance spectrum of NEM-SL(5) is similar in both soluble and vesicular cytochrome oxidase. Since ascorbate has been shown to reduce only spin label that is exposed to the exterior surface of a closed vesicle, we have used ascorbate to determine the NEM-SL(5)-binding site in the coupled vesicles; NEM-SL(5)-labeled cytochrome oxidase vesicles are reduced by 10 mM ascorbate with tau 1/2 of 1 min at 22 degrees C; The rate of reduction is relatively independent of temperature. We conclude that (1) cytochrome oxidase is unidirectionally or preferentially oriented in the vesicle membrane, and (2) the NEM-SL(5)-binding site on the 25 000 molecular weight subunit is exposed to the external aqueous medium.

Animals↗