Relaxation by Calcium Antagonists of Potassium-contracted Trachea from Normal and Sensitized Guinea-pigs: Influence of Epithelium and the Surface of Drug Entry

Abstract— A technique by which drug access was restricted to either the mucosal or the adventitial surface of tracheal rings, isolated from normal (unsensitized) or sensitized guinea-pigs, was used to study the role of the epithelium in the relaxation produced by calcium antagonists (verapamil, nifedipine, cinnarizine and flunarizine) of K⁺-induced contraction. In trachea from normal guinea-pigs, the relaxation to verapamil for unrestricted or mucosal drug entry was reduced in the absence of epithelium, whereas the relaxation produced by nifedipine, cinnarizine or flunarizine was unchanged. In sensitized trachea, the relaxation elicited by the calcium antagonists tested was similar in intact and epithelium-denuded tracheal rings irrespective of the surface of drug entry. These results confirm that the epithelium influences the relaxation to verapamil. This modulatory effect is absent in sensitized trachea and is not shared by other calcium antagonists.     

THYROID AUTOANTIBODIES IN HLA-GENOTYPED TYPE 1 DIABETIC FAMILIES: SEX-LIMITED DR5 ASSOCIATION WITH THYROID MICROSOMAL ANTIBODY

Thyroid autoantibodies are common in Type 1 diabetics and their first degree relatives and may be part of the autoimmune diathesis present within such families. We have measured the prevalence of microsomal (M-Ab) and thyroglobulin (Tg-Ab) autoantibodies in 84 HLA-typed families having a Type 1 diabetic child, using enzyme-linked immunosorbent assay techniques. Thyroid autoantibodies were detectable in 201/407 (49%) individuals in these families. Both autoantibodies were significantly more frequent in the subsets of parents, diabetic children and their non-diabetic siblings than in groups of control adults and children. The prevalence of these autoantibodies in the diabetic families was increased in both sexes with a female:male ratio of 1.4:1. Antigen DR5 was significantly associated with M-Ab production but only for male subjects (P = 0.005 after correction for the number of DR antigens tested). No significant associations were encountered for Tg-Ab. Within-family analyses indicated that thyroid autoantibodies occurred with increased prevalence in HLA-identical or haplo-identical siblings of autoantibody-positive index cases in comparison to control children. We conclude the DR association with thyroid autoantibody production in this diabetes-selected population was thyroiditis-related and not diabetes-related, and the DR5 association was restricted to males and the production of M-Ab. These data are consistent with the hypothesis that multiple genetic and non-genetic factors played a role in the high prevalence of thyroid autoantibodies in this population.     

RATIONALISATION OF THERAPY IN SEVERE EPILEPSY

Anticonvulsant therapy in 18 institutionalised adult epileptic persons was rationalised. The mean number of drugs administered was reduced from 3.2 to 2.0 per patient with improvement of seizure control in 11 patients and either no alteration or a mild deterioration of seizure control in seven patients. In this latter group however, there was an improvement in cerebellar signs andlor mentation associated with the reduction in drug therapy. It is proposed that even in patients with apparently severe epilepsy, whilst monotherapy may not be achieved, a significant reduction in the number of medications administered may be. Moreover medication can be effectively administered twice daily. (Aust NZ J Med 1983; 13: 601–604.)     

CURRENT CONCEPTS OE CUTANEOUS PORPHYRIA AND ITS TREATMENT WITH PARTICULAR REEERENCE TO THE USE OF SODIUM CALCIUMEDETATE

SUMMARY.— In the period 1955–69, 71 cases of porphyria have been diagnosed in South Australia, and include 4 cases of porphyria variegata and 34 cases of porphyria cutanea tarda. The general principles of treatment include the avoidance of alcohol, sunlight and trauma, and the establishment of a good dietary routine. Such principles lead to clinical remission in some cases, particularly in those who excrete less than 1 mg. of urinary porphyrins per day, but the majority also require active treatment and in South Australia sodium calciumedetate has been the treatment most used. We believe that it is possible to estimate the amount of chelation which will be necessary to obtain clinical remission: of the 28 treated patients with cutaneous porphyria whom we have been able to keep under observation, 27 obtained complete clinical remission following treatment with sodium calciumedetate.     

Changes in Plasma Atrial Natriuretic Peptide during Exercise in Healthy Volunteers

ABSTRACT. Thamsborg G, Storm T, Keller N, Sykulski R, Larsen J (Departments of Clinical Chemistry and Internal Medicine, Sundby Hospital, Copenhagen, and Department of Cardiology, Hvidovre Hospital, Hvidovre, Denmark). Changes in plasma atrial natriuretic peptide during exercise in healthy volunteers. Acta Med Scand 1987; 221:441–4. Graded exercise was performed in three healthy volunteers. Plasma levels of immunoreactive atrial natriuretic peptide (iANP) were determined at different workloads. Unchanged or slightly decreased plasma levels of iANP were observed during light exercise, whereas at medium to high workloads a considerable increase in plasma levels of iANP was found. Factors responsible for the increase in plasma levels of iANP might include elevated right atrial pressure and increased plasma levels of epinephrine and norepinephrine.