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Biomedical subjects

J L Turner

Publications and source records attributed to J L Turner.

At least 55 records · Page 3Linked to original sources
PubMed1983

Continuous perineural infusion of bupivacaine for prolonged analgesia: pharmacokinetic considerations.

The pharmacokinetic parameters for 50 patients undergoing continuous extravascular perineural bupivacaine infusions for the treatment of their chronic pain were studied. The total plasma clearance (CL), volume of distribution (Vz), and elimination rate (lambda z) were estimated from two blood samples. These parameters were compared to values obtained from the actual mono-exponential decay curve at the termination of infusion. Estimated and actual pharmacokinetic parameters were found to be in excellent agreement. No evidence of accumulation was seen even after 5 days of continuous infusion. Steady states (Css) were found to be independent of the infusion site. This study demonstrates a wide margin of safety during continuous perineural bupivacaine infusions at dosages used in our study, e.g., up to 30 mg/h in normal patients. Such patients do not require determination of serum bupivacaine concentration to monitor the changes in dosages necessary for adequate clinical effect. On the other hand, in patients with renal or hepatic dysfunction, altered clearance rates are expected. In such patients, monitoring of serum bupivacaine concentrations is necessary to determine the range of dosages available for adjustment to provide adequate clinical effect and prevent systemic toxicity. This study demonstrates that two blood samples drawn at 3-5 h after the start of infusion and at steady state are sufficient to accurately determine the clearance rate for a patient. Safe management is then possible using this clearance to calculate the range of dosages permissible for that patient during continuous perineural infusion. Steady-state concentrations estimated from clearances were found to be in excellent agreement with the steady-state concentrations actually measured for a given infusion rate.

Brachial Plexus↗
PubMed1982

Potential histamine H2-receptor antagonists. 4. Benzylhistamines.

As part of our studies aimed at designing histamine H2-receptor antagonists, the effect on histaminergic activity of introducing benzyl substituents at various positions in the histamine molecule is described. New synthetic methods are reported for the novel 4-benzyl-, beta-benzyl- and 4,N tau-dibenylhistamines and the reported 2-benzylhistamine. The novel N tau-benzylhistamine was synthesized by the versatile route reported by us for the synthesis of N tau-methylhistamine. These benzylhistamines, together with the reported N alpha- and N pi-benzylhistamines, were tested for agonist and antagonist activity at both H1 and H2 receptors. The results obtained indicate that introduction of a benzyl group into the histamine molecule causes a marked reduction in H1- or H2-agonist activity, and none of the compounds showed consistent antagonist activity. Evidently, the sterically demanding benzyl substituent is not easily accommodated in the agonist binding mode and is unable to locate a lipophilic receptor region for potential hydrophobic binding.

Animals↗
PubMed1981

Control of pain by mefenamic acid following removal of impacted molar. A double-blind, placebo-controlled study.

The efficacy of mefenamic acid, aspirin, and placebo in the control of postsurgical pain was compared in a double-blind, randomized study of forty-seven patients. Medication was begun as soon as the anesthetic began to wear off and was continued as needed to a maximum of eight doses over a 48-hour period. The results were analyzed in terms of the patient's assessment of postsurgical pain, and the patient's and the investigator's evaluation of drug efficacy. In the population studied, mefenamic acid was well tolerated. Mefenamic acid was clearly superior to placebo and equalled or exceeded the ability of aspirin to control postsurgical pain in the parameters measured.

Adolescent↗
PubMed1981

Lymphokine production by human milk lymphocytes.

To assess the functional capability of human milk lymphocytes, we studied phytohemagglutinin-induced lymphokine production by breast milk and, for comparison, peripheral blood lymphocyte cultures. Two lymphokines, lymphocyte-derived chemotactic factor (LDCF) and immune interferon, were assayed in supernatants of milk and blood lymphocyte cultures obtained from women 2 to 6 days postpartum. Eleven parallel milk and blood samples were studied for LDCF production. In nine experiments, both milk and blood lymphocytes produced LDCF. In the two other experiments, milk cells did not produce LDCF. In 10 milk cultures studied, all produced interferon activity. Acid and heat lability characteristics were typical of immune interferon. These results further characterize milk lymphocytes as immunologically competent and possibly important effector cells in neonatal immunity.

Animals↗
PubMed1980

Control of pain resulting from endodontic therapy: a double-blind, placebo-controlled study.

The efficacy of mefenamic acid, aspirin, and a placebo for control of postendodontic pain was compared in a double-blind, randomized study of 150 patients. Medication was begun immediately prior to the endodontic therapy and continued for a total of eight doses. The results were analyzed in terms of the patients' assessments of postendodontic pain, the need for additional analgesic medication, and the patients' and investigator's evaluations of drug efficacy. The results indicate that mefenamic acid was well tolerated. Mefenamic acid was equal to, or exceeded, aspirin in ability to control postendodontic pain in every comparison made. The converse was never true. Mefenamic acid was statistically superior to placebo in every comparison made. Aspirin was not consistently superior to the placebo. Under the conditions of this trial, it can be stated that, for control of pain following simple endodontic therapy, mefenamic acid rather than aspirin is the drug of choice.

Adolescent↗
PubMed1980

Breast milk lymphocyte response to K1 antigen of Escherichia coli.

Comparison milk and blood lymphocyte blastogenic responses to the K1 antigen of Escherichia coli and lipopolysaccharide (LPS) from E. coli O127,B8 were examined in 16 postpartum women by [3H]thymidine uptake. Rabbit hemolysincoated sheep erythrocyte monolayers were used to deplete macrophages from milk lymphocyte preparations and to enrich for T lymphocytes in order to make milk preparations more comparable to blood preparations. Response was defined as a stimulation index of greater than or equal to 2.0. There was no evidence of selective response to K1 antigen by milk lymphocytes, since both blood and milk lymphocytes responded in four women and neither blood nor milk lymphocytes responded in nine. Milk lymphocytes alone responded to K1 in one woman, whereas blood lymphocytes alone responded in two women. Additional nonpaired milk or blood cultures were available from three women. None of these responded to K1 antigen. Corresponding lymphocyte cultures were stimulated with LPS. A positive K1 response was always accompanied by an LPS response, and the LPS response correlated with the K1 response in 17 of 19 women. Stool cultures examined with an antiserum agar showed no correlation between the presence of K1 E. coli in the stool and milk or blood lymphocyte response to K1 antigen. In the system used here, no selectivity of response of breast milk lymphocytes to K1 antigen was noted.

Antigens, Bacterial↗
PubMed1980

Ewing's tumor metastatic to the clivus, simulating meningitis: case report.

Ewing's sarcoma, which is regarded as one of the most lethal primary bone tumors, lies in the domain of the orthopedic surgeon because it occurs most commonly in the shaft of the long bones, especially in the lower extremities. Pain, leukocytosis, fever, anemia, and an elevated erythrocyte sedimentation rate are commonly seen. We are presenting a case of Ewing's sarcoma of the left greater trochanter with metastasis to the clivus producing a bilateral 6th nerve palsy. The presence of fever, nuchal rigidity, and photophobia simulated meningitis. The rapid evolution of radiological signs will be discussed.

Abducens Nerve↗
PubMed1979

Effect of dietary fructose on triglyceride transport and glucoregulatory hormones in hypertriglyceridemic men.

Effects of dietary fructose on triglyceride metabolism and on basal levels and meal responses of glucose, insulin, and glucagon were studied in six hypertriglyceridemic men, two of whom were also diabetic. Constant composition, weight-maintaining formula diets were used with substitution of fructose for 20% of the carbohydrate calories in both fat-containing (45% carbohydrate) and fat-free (85% carbohydrate) periods; each of the four dietary periods was at least 2 weeks long in every subject. No effect of fructose on fasting levels of triglycerides could be seen in any of the diets. No alterations of triglyceride transport occurred with fructose substitution in the fat-containing diets, but significant reductions of triglyceride transport rates were seen with fructose substitution in the 85% carbohydrate diets using both the heparin infusion lipolytic rate method and the 3H-glycerol methods of assessment of tryglyceride turnover (- 16 and - 21%, respectively). Dietary fructose induced no significant changes in either basal levels or responses during a "formula tolerance test" of glucose, insulin, or glucagon. Thus, dietary fructose given for several weeks does not appear to cause further elevations of plasma triglyceride levels in hypertriglyceridemic men.

Adult↗
PubMed1978

Effects of glucose and sorbitol on proliferation of cultured human skin fibroblasts and arterial smooth-muscle cells.

To determine effects of metabolic abnormalities associated with diabetes mellitus on proliferation of diploid human cells, cultured human skin fibroblasts and arterial smooth-muscle cells were grown in media containing added glucose in the range often seen in diabetic subjects (10 to 30 mM, 180 to 550 mg./dl.). "High" glucose media enhanced proliferation of fibroblasts, with an "optimal" response at about 18 mM (325 mg./dl.). Equimolar sorbitol gave similar results, with the greatest increase in proliferation occurring at about the same concentration as for glucose (1 mM). Since neither equimolar mannitol nor sucrose produced such effects consistently, these results cannot be explained solely on the basis of hyperosmolarity. In contrast, arterial smooth-muscle cells failed to show a consistent growth response in the presence of either added glucose or sorbitol. These results suggest that studies with cultured human cells may be useful in assessment of responses to components of the disordered metabolic milieu of diabetes. Such studies of arterial smooth-muscle cells should also be useful for investigation of the mechanism of atherosclerosis in diabetes.

Arteries↗
PubMed1978

Abnormal function of endocrine pancreas and anterior pituitary in Friedreich's ataxia. Studies in a family.

A family had three siblings affected with classic Friedreich's ataxia. One sibling died at age 20 with fulminant diabetic ketoacidosis. The other two affected siblings are identical twin sisters without clinical diabetes but with an abnormality in the metabolism of exogenously administered glucose. These twins also have abnormal hypothalamic-pituitary control of prolactin and possibly of growth-hormone secretion. This study extends the previous reports of endocrine deficienceis associated with Friedreich's ataxia. The mechanisms underlying this association are undetermined but could represent pleiotropic effects of the Friedreich's ataxia gene or secondary manifestations of the primary central nervous system degeneration, or both.

Adult↗
PubMed1976

Ethosuximide dosage regimens.

A study was conducted in 9 children with petit mal epilepsy to compare the plasma levels of ethosuximide after divided daily administration with those after single daily administration. The children received their previously established dose in divided doses for 4 wk, single morning doses for 4 wk, and again in divided doses for 4 wk. None of the children suffered petit mal seizures during the study. Three had grand mal seizures but the frequency did not differ between the dosage regimens. Plasma levels during the single-dose period peaked more rapidly and fell more quickly than during the other periods, but mean levels remained in the therapeutic range. The mean half-life of the drug in these children was 29 hr. For reasons not understood, plasma levels generally were lower in the second divided dose period than in the other two periods. No adverse experiences were reported during the study. The data indicate that ethosuximide is clinically effective when given in a single daily dose. This regimen offers advantages in convenience and possibly in patient compliance.

Adolescent↗