Noncyclooxygenase oxidative formation of a series of novel prostaglandins: analytical ramifications for measurement of eicosanoids

Analysis of fresh plasma from normal volunteers by negative ion chemical ionization GC/MS reveals what appear to be multiple PGF2 compounds with levels ranging from approximately 5 to 40 pg/ml. Interestingly, storage of plasma at -20 degrees C for several months was found to markedly increase the levels of these compounds to about 1000-4000 pg/ml, approximately 50-fold higher than levels detected in fresh plasma. Further studies aimed at understanding this observation revealed that alkaline hydrolysis of plasma lipids also yielded quantities of these compounds in the range that were detected in stored plasma. Employing a number of approaches such as deuteriated derivatives, hydrogenation, immunoreactivity with an anti-9 alpha, 11 beta-PGF2 antibody, and electron ionization mass spectral analysis, convincing evidence was obtained that these compounds in both stored and base-treated plasma were in fact PGF2 compounds. Formation of these compounds was found to occur by a nonenzymatic oxidative process in that the antioxidant, butylated hydroxytoluene, and the reducing agent, triphenylphosphine, markedly suppressed their formation. Evidence is presented to support a proposed mechanism that oxidative formation of these compounds involves the formation of endoperoxide intermediates which are directly reduced by naturally occurring biological substances to PGF2 compounds. Formation of these compounds occurs very readily in biological fluids. This finding has important ramifications not only for analysis of enzymatically derived PGF2 compounds but also for other eicosanoids which can be formed by this same nonenzymatic process. These analytical concerns apply to both immunoassay methods and physical methods of analysis such as gas chromatography/mass spectrometry.

A preliminary investigation of the relationship between certain practice characteristics and practice location: chiropractor-population ratio

Two surveys of 121 preselected Victorian and South Australian chiropractors were conducted during the period of December 1986 to February 1987 in order to investigate whether practice location (metropolitan area and country town) and chiropractor/population ratio (number of chiropractors per 10,000 inhabitants) have any effect on patient numbers, practice procedures and practitioner attitudes. Practitioners' response rates to the first and second questionnaires were 82% and 61%, respectively. Analysis of data revealed that metropolitan chiropractors utilized more adjunctive therapies than their country town colleagues. Most chiropractors felt that the number of chiropractors in their area was sufficient. However, there appeared to be no difference in patient numbers (patient visits and new patients) and ratio of new patients to patient visits as related to practitioner density or practice location. Patient volume appeared to be practitioner-induced; fewer new patients corresponded to a higher number of revisiting patients, and maintenance care corresponded to a higher number of patient visits.

Release of markedly increased quantities of prostaglandin D2 in vivo in humans following the administration of nicotinic acid

Nicotinic acid (niacin) is a B vitamin which is also a potent hypolipidemic agent. However, intense flushing occurs following ingestion of pharmacologic doses of niacin which greatly limits its usefulness in treating hyperlipidemias. Previous studies have demonstrated that niacin-induced flushing can be substantially attenuated by pre-treatment with cyclooxygenase inhibitors, suggesting that the vasodilation is mediated by a prostaglandin. However, the prostaglandin that presumably mediates the flush has not been conclusively determined. In this study we report the finding that ingestion of niacin evokes the release of markedly increased quantities of PGD2 in vivo in humans. PGD2 release was assessed by quantification of the PGD2 metabolite, 9 alpha, 11 beta-PGF2, in plasma by gas chromatography mass spectrometry. Following ingestion of 500 mg of niacin in three normal volunteers, intense flushing occurred and plasma levels of 9 alpha, 11 beta-PGF2 were found to increase dramatically by 800, 430, and 535-fold. Levels of 9 alpha, 11 beta-PGF2 reached a maximum between 12 and 45 min. after ingesting niacin and subsequently declined to near normal levels by 2-4 hours. Levels of 9 alpha, 11 beta-PGF2 in plasma correlated with the intensity and duration of flushing that occurred in the 3 volunteers. Release of PGD2 was not accompanied by a release of histamine which was assessed by quantification of plasma levels of the histamine metabolite, N tau-methylhistamine. This suggests that the origin of the PGD2 release is not the mast cell. Only a modest increase (approximately 2-fold) in the urinary excretion of the prostacyclin metabolite, 2,3-dinor-6-keto-PGF1 alpha, occurred following ingestion of niacin and no increase in the excretion of the major urinary metabolite of PGE2 was found. These results indicate that the major vasodilatory PG released following ingestion of niacin is PGD2. The fact that markedly increased quantities of PGD2 are released suggests that PGD2 is the mediator of niacin-induced vasodilation in humans.

Eaton-Lambert syndrome in a patient with acute T cell lymphocytic leukemia

We have reported the first case of the Eaton-Lambert syndrome associated with leukemia in an adult, a 74-year-old woman with acute T cell lymphocytic leukemia and a mediastinal mass accompanied by weakness of the upper and lower extremities and pain in the lower extremities. Electromyographic studies were diagnostic of the syndrome. Treatment with guanidine hydrochloride resulted in clinical improvement of the neuromuscular disease, but the patient died of refractory leukemia.

Case report: dapsone hypersensitivity syndrome associated with treatment of the bite of a brown recluse spider

Dapsone (4-4-diaminodiphenyl-sulfone) is a member of the sulfone group of antibiotics used in the treatment of leprosy and various dermatitidies and more recently employed in the management of local reactions to the bite of the brown recluse spider, Loxosceles reclusa. A dapsone hypersensitivity syndrome, consisting of fever, headache, nausea, vomiting, lymphadenopathy, hepatitis, hemolysis, leukopenia, and mononucleosis, has been described in patients treated with the drug for leprosy. A case report of the hypersensitivity syndrome occurring in a patient being treated with dapsone for a brown recluse spider bite is presented.

Percutaneous transluminal dilatation of the renal artery: follow-up studies on renovascular hypertension

Percutaneous transluminal dilatation of 80 renal artery stenoses was attempted in 68 patients. The procedure was technically successful in 58 (85%) patients. Fifty (86%) of the 58 patients were initially cured or improved. Life-table analysis of this group gives a cumulative success rate of 81% for a 3 year period. Hypertension recurred in only seven patients. There were no deaths related to the procedure, but four major complications occurred, including two secondary nephrectomies.

Pheochromocytoma in the modern context

The hypertensive patient faces an uncertain future. Therefore a search for those cases in which the condition is potentially curable is eminently worth while and has become increasingly productive because of the specific diagnostic aids now available and because of the present safety of surgical intervention. Detection and localization of a pheochromocytoma allows a planned surgical approach. Correction of hypovolemia preoperatively ensures a safe course postoperatively. The use of blocking agents pre- and peroperatively prevents the hazardous hypertensive crises and arrhythmias that were a part of early surgical experience. Monitoring of central venous and arterial pressures as well as the electrocardiographic tracing during the operation permits prophylactic therapy when necessary. On the basis of a series of 31 patients the authors compare many aspects of the current management with earlier experience of pheochromocytoma in the same institution. The incidence of extra-adrenal lesions (3.8%), multicentric tumours (3.8%) and malignant change (11.5%) was lower in this group of patients than that usually reported. Abdominal exploration remains the approach of choice in most cases. Treatment of the solitary pheochromocytoma has become straightforward. However, management of the familial syndromes and the malignant from of the disease still requires careful scrutiny.