Essential tremor

Essential tremor is a common disorder whose aetiology is unknown. Characteristically it is present on maintaining posture, absent at rest, and not made significantly worse with movement.     

Protein synthesis and degradation in skeletal muscle of chronically uremic rats

We used the perfused hemicorpus preparation to measure individual rates of protein synthesis and degradation. Using fed animals, perfused either with or without insulin, muscle protein synthesis and hemicorpus protein degradation rates were similar, but myofibrillar protein degradation was clearly increased in the uremic preparations. When the animals were fasted, differences in the rates of skeletal muscle protein turnover were apparent. Uremic rats lost more wt at both 24 and 48 hr of fasting when compared to either ad libitum fed or pair-fed controls who started fasting at body wts equivalent to our uremic rats. The accelerated wt loss was accompanied by lower rates of protein synthesis, higher degradation rates, and greater net protein catabolism in our uremic rats. Alterations in body lipid content were present in uremia and correlated with the rate of protein degradation in both control and uremic rats. These data demonstrated that even in the fed state, uremia is associated with subtle alterations in skeletal muscle protein turnover. When stressed, these alterations become more pronounced. Insufficient stores of body lipids, either due to inadequate nutrition or altered metabolism, may contribute to the alterations in muscle protein turnover seen in chronic renal insufficiency.     

Natural history of penetrating ocular injury with retinal laceration in the monkey

In one eye each of four cynomolgus monkeys, an 8-mm penetrating injury was made through the equator; there was retinal perforation with vitreous loss. None of the four eyes with this injury developed posterior vitreous detachment or retinal detachment during a follow-up period of 8 months to 1 year.Another group of 26 monkeys had the same injury but also had 0.5 ml autologous whole blood injected into the vitreous at the time of injury. The eyes were examined weekly and enucleated at scheduled intervals from 1 day to 52 weeks post-injury. Posterior vitreous detachment occurred at the earliest at 2 weeks post-injury, and was ultimately present in 91% of the eyes. Vitreous detachment can occur either as a separation at the level of the internal limiting membrane or as a cleavage within the cortical vitreous. Retinal detachment occurred at the earliest at 8 weeks post-injury, and eventually was present in 50% of the eyes. The retinal detachment was tractional; no retinal breaks were detected in any of the eyes.This study was supported by grants EY02061 and EY03040 from the National Institutes of HealthPresented at the 1984 meeting of the Club Jules Gonin in Lausanne, Switzerland     

A method for evaluating antianginal drugs in experimental animals: assessment of myocardial ischemia by myocardial pH

This paper describes a method by which antianginal drugs can be evaluated in the dog heart in situ. Myocardial pH was measured continuously by a micro glass pH electrode inserted in the left ventricular endocardial layers of the dog anesthetized with pentobarbital. Occlusion of the left anterior descending coronary artery (LAD) decreased myocardial pH, and release of the LAD restored the pH. The myocardial acidosis induced by ischemia was metabolic in nature and accompanied by a decrease in the levels of adenosine triphosphate and creatine phosphate and an increase in the levels of lactate in the myocardium. Drugs were injected intravenously 30 min after incomplete (partial) occlusion ot the LAD, lasting until 60 min after drug injection. Propranolol, atenolol, and sotalol markedly attenuated the myocardial pH that had been decreased by LAD occlusion. Nitroglycerin, diltiazem, and nicorandil also attenuated the pH, but these drugs were less active in attenuating myocardial acidosis. Dipyridamole, nifedipine, and beta-2 adrenoceptor antagonists were least active in this regard. It is concluded that myocardial pH can be used as an indicator of myocardial regional ischemia and utilized for evaluation of antianginal drugs.     

Effects of antimalarial drugs on interleukin 1-induced cartilage proteoglycan degradation in-vitro

Previous studies having shown that chloroquine and hydroxychloroquine could reduce interleukin 1 (IL-1)-induced cartilage degradation in-vitro, the effects of a range of antimalarial drugs on the cartilage proteoglycan degrading actions of porcine leucocyte (pI 4.8) alpha-interleukin 1 (syn. catabolin) have been examined using the standard bovine nasal cartilage culture system. The anti-IL-1 effects in this system were specific to several aminoquinoline and aminoacridine analogues having a side chain with a tertiary amino group similar to that of chloroquine. Aminoquinoline compounds devoid of this side chain and the tertiary amino, as well as pyrimidines or biguanides with antimalarial activity were without effect. Mefloquine, the most potent of the compounds active against porcine alpha-IL-1, was only equipotent with chloroquine and its hydroxyanalogue against human recombinant alpha-IL-1. This suggests that there may be subtle differences in the receptors for these drugs and interleukins in bovine cartilage. The results provide further evidence for the specificity and utility of antimalarial drugs in the treatment of chronic inflammatory conditions, especially in relation to actions on IL-1.