Search PubMed⌕ Search

Biomedical subjects

L Smith

Publications and source records attributed to L Smith.

At least 613 records · Page 34Linked to original sources
PubMed1981

The role of the physician in the grief process.

A child's death is a particularly painful experience for the family. The grief process involves all family members, and although it is individualized many reactions and concerns are predictable. With knowledge of the grief process, the patient's physician may be of great assistance to the family during this time of need. A plan is suggested for helping the family to cope with their feelings.

Attitude to Death↗
PubMed1981

Posttetanic potentiation in a patient with myasthenia gravis.

We studied a patient with clinically typical myasthenia gravis (MG) and high serum titer of antibodies to acetylcholine receptor. Unlike the usual response in MG, there was an increment in the amplitude of the electrical response (308% of control) after 10 seconds of voluntary tetanus. Posttetanic facilitation is usually less than 200% in MG and over 200% in Eaton-Lambert syndrome. However, there have been several other cases of typical MG with increments over 200%. Facilitation of this magnitude has also been seen with curare administration in animals and man. However, in myasthenia, as opposed to curare poisoning, competitive blocking is not thought to exist.

Autoantibodies↗
PubMed1980

Effect of adenosine 5'-triphosphate and adenosine 5'-diphosphate on the oxidation of cytochrome c by cytochrome c oxidase.

Adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), and inorganic pyrophosphate partially inhibit the oxidation of exogenous cytochrome c by cytochrome c oxidase of submitochondrial particles (with or without detergent treatment) or by a purified preparation when it is assayed polarographically in buffers of nonbinding ions at pH 7.8. ATP is somewhat more inhibitory than ADP. The inhibition is never greater than 50%, and it is always less than an equal concentration of Mg2+ ions is present or when the assays are run at pH 6. In contrast, the effect of ATP, ADP, and pyrophosphate on oxidase assays run spectrophotometrically is a similar slight stimulation of the oxidase of submitochondrial particles treated with deoxycholate and little or no effect on purified oxidase. The reaction of the oxidase of submitochondrial particles with the endogenous cytochrome c is stimulated by the nucleotides, as is the reduced nicotinamide adenine dinucleotide (NADH) oxidase activity. The observations can be explained by binding of ATP, ADP, or pyrophosphate to cytochrome c so that the formation of an especially reactive combination of cytochrome c and cytochrome oxidase previously postulated [Smith, L., Davies, H. C., & Nava, M. E. (1979) Biochemistry 18, 3140] is prevented. The data give no evidence that respiration via cytochrome c oxidase is regulated physiologically by direct effects of ATP or ADP on its activity.

Adenosine Triphosphate↗
PubMed1980

Bile bacteria in patients with benign bile duct stricture.

In a prospective study of 73 patients undergoing hepatodochojejunostomy for benign bile duct stricture who were covered by antibacterial prophylaxis with gentamicin and cephalolothin, bacteria were cultured from bile sampled at operation in 80 per cent of cases. Aerobic organisms were found in 50 cases (82 per cent) and anaerobic organisms in 11 cases (18 per cent). Seventy-three per cent of the patients with postoperative septic complications had bile cultures positive for anaerobes at operation, and the same organisms were cultured from pus. All patients with anaerobes in the bile at some time in the perioperative period developed postoperative sepsis. Antibacterial prophylaxis with gentamicin and cephalothin, together with specific therapy with drugs effective against anaerobes when indicated, are recommended in the management of these cases.

Bacteria↗
PubMed1980

Metabolism of aflatoxin B1, benzo[a]pyrene, and 1,2-dimethylhydrazine by cultured rat and human colon.

A model system for comparing carcinogen metabolism between human and rat colon has been developed. Tissue explants maintained under chemically defined conditions were treated with radioactively labeled carcinogens. After incubation for 24 hours, the binding of radioactive carcinogen to DNA was quantitated. Further, the carcinogen-DNA adducts and carcinogen metabolites released into the culture media were identified. Both human and rat colon activate benzo[a]pyrene (BP), aflatoxin B1 (AFB), and 1,2-dimethylhydrazine (DMH) into chemical species that reacted with cellular macromolecules. When human and rat colons were compared, the metabolism of AFB and DMH was qualitatively similar - the same major carcinogen-DNA adducts and metabolic profile. However, the mean binding levels of DMH and AFB to colonic DNA were higher in rats than in humans. BP-guanine adducts were the major adducts formed by both rat and human colonic DNA. However, BP-adenine adducts were observed in rat colonic DNA but not in human colonic DNA. A positive correlation for the binding of BP and DMH to human DNA of different individuals was observed, but no correlation was found between BP and AFB. The data suggest that similar enzyme systems may be involved in the metabolism of BP and DMH, whereas different enzymes might be involved in the metabolic activation of AFB.

1,2-Dimethylhydrazine↗
PubMed1980

Glutamine therapy of cystinuria.

We studied the urinary excretion of cystine, acids, and cystine crystalluria in five patients with homozygous cystinuraia before and during oral glutamine therapy. Oral glutamine did not change the absolute urinary excretion or fractional excretion of cystine in our patients and did not significantly affect urinary pH. Cystine crystalluria was present before and during oral glutamine therapy.

Administration, Oral↗
PubMed1980

Metabolism of 1,2-dimethylhydrazine by cultured human colon.

The overall metabolism of 1,2-dimethylhydrazine, and organotropic colon carcinogen in rodents, has been studied using human colon explant cultures. The binding level of 1,2-dimethylhydrazine to DNA which in this study includes both reaction of metabolites with DNA and incorporation of radioactive metabolites into DNA, showed a 100-fold variation among the 120 people studied. When different anatomical colonic sites were compared, the highest mean binding levels were found in the ascending and sigmoid colon. No significant difference in the median and mean binding levels were observed in nontumorous colon obtained surgically from patients with colon cancer and colon obtained from immediate autopsy, but decreased mean binding levels were seen in tissues obtained by surgery from patients with non-cancerous colonic disorders. Several exogenous chemicals were found to modify the metabolism. When the colon explants were co-incubated with 1,2-dimethylhydrazine and these chemicals, the binding level of 1,2-dimethylhydrazine to DNA was (a) increased by either indole 3-carbinol or phenobarbital, (b) decreased with disulfiram, butylated hydroxytoluene, or taurodeoxycholic acid, and (c) unaltered by lithocholic acid.

1,2-Dimethylhydrazine↗
PubMed1980

Thoracic epidural vs balanced anesthesia in morbid obesity: an intraoperative and postoperative hemodynamic study.

Thirty-eight morbidity obese patients undergoing gastric bypass were divided into two groups. All patients received general endotracheal anesthesia with muscle relaxation and controlled respiration with N2O-O2 mixture. In addition, group I, 17 patients, received balanced anesthesia, while the remaining 21 patients, group II, received thoracic (T-5) epidural analgesia. Postoperative analgesia was achieved with morphine intravenously in group I and with 0.5% bupivacaine epidurally in group II. Circulatory function was measured and calculated using radial artery cannulation and pulmonary artery catheterization with Swan-Ganz thermodilution catheters. A significant decrease in cardiac index (10% and 14% in groups I and II, respectively), in left and right ventricular stroke work (12% to 30%), systolic blood pressure-heart rate product (16% and 28% in groups I and II, respectively), in arterial venous oxygen content difference and oxygen consumption (31% and 39% in groups I and II, respectively) was observed during surgery. A decrease in intrapulmonary shunt from 20% +/- 2.9% before anesthesia to 15% +/- 2.1% intraoperatively was seen in patients given epidural anesthesia. Postoperatively epidural analgesia was associated with a decrease in left ventricular stroke work 12%), systolic pressure-heart rate product (10%), arteriovenous oxygen content differences (17%), and oxygen consumption (20%), compared with values observed when patients experienced pain. Morphine given for relief of postoperative pain was not associated with significant changes in cardiovascular function. Continuous epidural analgesia used postoperatively for relief of pain in morbidity obese patients, following upper abdominal surgery, slightly decreases oxygen requirement and benefits cardiovascular function as reflected by a decrease in left ventricular stroke work.

Adult↗