Diphenylhydantoin-induced hepatic necrosis. A case study

A patient with post-traumatic seizure disorder developed lymphadenopathy, exfoliative dermatitis, and hepatic failure while on diphenylhydantoin therapy and died in hepatic coma. Autopsy disclosed massive hepatic necrosis. The clinical and pathological pictures are similar to the six previously reported cases of diphenylhydantoin-induced hepatic necrosis, with the exception of the time of onset of hepatic failure, which is explained. The cause of such hepatotoxicity is unknown, although hypersensitivity is postulated. It appears that studies of liver function in patients receiving diphenylhydantion are indicated to assess the true indicence of hepatocellular injury.

Nonsympathetic dilator innervation of cat cerebral arteries

The results presented provide strong support for the presence of vasodilator innervation in the cat cerebral arteries. The dilator innervation is neither adrenergic nor cholinergic and does not originate in the superior cervical ganglia. The nature of the vasodilator transmitter is unidentified. Such innervation, however, may be involved in the regulation of cerebral blood flow, especially in view of the capability of some cat cerebral vessels to develop intrinsic muscle tone.

Vitamin E deficiency and platelet functional defect in a jaundiced infant

A 16-month-old infant with hepatic fibrosis, cholestasis, and chronic jaundice had signs of vitamin E deficiency, including mild acanthocytosis, thrombocytosis, increased peroxide haemolysis, and absent serum vitamin E. Abormal prothrombin consumption and platelet restocetin aggregation suggested the presence of defective platelet function, and correction studies indicated that this was due to a plasma defect. The abnormality was corrected by treatment with vitamin E, and the findings suggest a possible role of this vitamin in platelet reactions.

Morphological and biochemical changes in supersensitive smooth muscle

The effect of postganglionic denervation on the incidence of nexal contacts in the smooth muscle of the rat vas deferens was investigated. The chronically denervated tissue exhibited twice as many nexuses as control. This increase in the incidence of cell contacts may contribute to the supersensitivity and/or the increase in maximum response of the denervated vas deferens. The effects of denervation, decentralization, and pretreatment with reserpine on the concentration of adenosine triphosphate (ATP) in vasa deferentia of rats and guinea pigs were also investigated. One day after denervation there was a substantial decrease in the endogenous norepinephrine and ATP concentrations. The norepinephrine concentration remained low (less than 10% of control) throughout subsequent days (up to 14 days) whereas the ATP concentration, after the first postoperative day, rose significantly. The rise in ATP concentration was temporally correlated with the development of postjunctional supersensitivity. Decentralization and pretreatment with reserpine both resulted in a significant increase in ATP concentration which preceded by 2 to 3 days a significant increase in sensitivity of the vas deferens. It appears that a change in the tissue concentration of ATP may be one of the initial events that occurs following interruption of the neural contact to the smooth muscle of the vas deferens.

Histamine potentiation of nerve- and drug-induced responses of a rabbit cerebral artery

Rabbit basilar artery rings are normally relatively unresponsive to transmural stimulation of their sympathetic nerve supply. However, in the presence of histamine (0.55 muM), contractile responses to nerve stimulation were markedly increased. Norepinephrine and serotonin concentrations that produce 50% of a maximum contractile response (ED50) were considerably decreased in the presence of histamine; maximum responses to both norepinephrine and serotonin were increased. Although a prejunctional effecto of histamine has not been eliminated, potentiation of responses to transmural nerve stimulation is probably due to an increase in smooth muscle responsiveness to norepinephrine. In rabbit saphenous artery rings, histamine produced a qualitatively similar potentiation of responses to nerve stimulation, norepinephrine, and serotonin except that maximum responses were not increased. Serotonin (0.084 muM) did nog potentiate contractile responses of the basilar artery to transmural nerve stimulation or norepinephrine. Since histamine and serotonin are released from rabbit platelets in response to tissue injury the synergistic effect of these agents on vascular smooth muscle contraction might be advantageous in minimizing hemorrhage. But such a response could also be deleterious if the effects of these vasoconstrictors were prolonged.

The correlation between spontaneous contractions and postjunctional supersensitivity of the smooth muscle of the rat vas deferens

Chronic postganglionic denervation of the rate vas deferens produces an increase in the sensitivity of the in vitro smooth muscle to norepinephrine, methoxamine, acetylcholine, potassium and electrical stimulation. The maximal contractile response to norepinephrine and acetylcholine is increased but the maximal response to potassium or electrical stimulation is not affected. In addition, the vas deferens becomes spontaneously active after denervation. The spontaneous contractions are not prevented by tetrodotoxin, phentolamine or atropine. The appearance and magnitude of the spontaneous contractions are temporally correlated with the development of postjunctional supersensitivity. At a given time after denervation there is a significant correlation between the magnitude of the spontaneous contractions and the sensitivity to norepinephrine, i.e., the sensitivity to norepinephrine being greatest in those tissues with the largest spontaneous contractions. There is an inverse relationship between the magnitude of the spontaneous contractions and the endogenous norepinephrine concentration. Pretreatment of rats with reserpine (1. 0 mg/kg/day for 5-7 days) results in supersensitivity of the vas deferens ,o norepinephrine and acetylcholine. Those tissues obtained from reserpine-pretreated rats which are supersensitive are also spontaneously active. It is concluded that the -ppearance of spontaneous contractions in the rat vas deferens is an index of postjunctional supersensitivity.