First branchial cleft fistula: case reports and literature review

The 1st branchial cleft accounts for about 5% of branchial arch anomalies. The necessity for wide surgical exposure to delineate the anatomy between the facial nerve and tract is stressed; migrating mesenchyme, which brings with it the facial nerve, can orientate medically, laterally or both sides of the tract. Three cases and a literature review are presented.

Ionic mechanisms implicated in the stimulation of cerebellar cyclic GMP levels by N-methyl-D-aspartate

N-Methyl-D-aspartate (NMDA) increases cyclic GMP levels in immature rat cerebellar slices incubated in magnesium-containing Krebs buffer in vitro. This effect is blocked by 2-amino-5-phosphonovalerate and by D-alpha-aminoadipate, but not by glutamic acid diethyl ester or gamma-D-glutamylaminomethylsulfonic acid, indicating specific involvement of the NMDA receptor. The response produced by NMDA is abolished by removal of calcium from the medium, proportional to the concentration of extracellular calcium, and blocked by a number of inorganic (Ni2+, Co2+, Cd2+, La3+, Mn2+) calcium antagonists. The responses to NMDA are not blocked by barium or strontium and persist when these ions are substituted for calcium in the incubation medium. The effects of NMDA are blocked by, but are not particularly sensitive to, the organic voltage-dependent calcium channel antagonists. Nifedipine (10 microM) produces partial inhibition of the effects of NMDA, which are also antagonized by high (greater than 200 microM) concentrations of diltiazem and verapamil. The effects of NMDA are tetrodotoxin insensitive but are abolished by omission of sodium from the medium and inhibited by a tetrodotoxin-insensitive sodium channel blocker, Zn2+. The results suggest that calcium channel opening is a consequence of NMDA receptor activation in this model. However, the sodium dependence of the response argues against the use of receptor-operated calcium channels, whereas the weak activity of the organic voltage-sensitive calcium channel antagonists argues either against the use of voltage-dependent calcium channels, or that those implicated in the effects of NMDA are insensitive to these agents.(ABSTRACT TRUNCATED AT 250 WORDS)

A procedure of vestibular decompensation for clinical diagnosis. I. Animal experiments

Vestibular lesions are often so effectively compensated that their diagnosis may be difficult. Certain chemicals can decompensate the central vestibular system and thus uncover symptoms present before compensation. This study attempts to devise a procedure which can utilize such decompensation for the benefit of clinical diagnosis. Unilateral labyrinthectomies were performed in rats. Pathological movements and body positions due to the vestibular loss were compensated within about one week. Systemic application of cholinomimetic drugs (physostigmine and nicotine) led to consistent decompensation which lasted, however, too long and was accompanied by too severe side effects to be considered for clinical diagnostic purposes. Local application of these drugs into the middle ear of the healthy side were without effect. Brief inhalation of nitrous oxide (up to 79 vol.%) caused decompensation during the first four postoperative weeks but not consistently at longer survival times. Inhalation of halothane in N2O and O2 for 90 seconds caused a reliable decompensation at all times during the six month postoperative observation period. It is concluded that a brief halothane-N2O anesthesia may prove to be useful in a diagnostic search for compensated vestibular deficits.

Heterogeneity of ouabain specific binding sites and (Na+ + K+)-ATPase inhibition in microsomes from rat heart

Cardiac glycoside binding to microsomes prepared from rat heart ventricles and enriched in (Na+ + K+)-ATPase was measured by a rapid filtration technique. The relation between ouabain binding to microsomes and (Na+ + K+)-ATPase activity has also been examined. Data were statistically analysed by means of two different non linear regression methods. The experimental results were fitted the most closely by a model describing that ouabain specific binding occurred at two classes of independent sites. High affinity sites were characterized by a dissociation constant of 0.21 +/- 0.01 microM and a low capacity (9.4 +/- 1.4 pmoles/enzymatic unit). Low affinity sites were characterized by a dissociation constant equal to 13 +/- 3 microM and a capacity equal to 87 +/- 15 pmoles/enzymatic unit. Similar results were obtained with the more lipophilic glycoside digoxin. It was also observed that dihydroouabain, a ouabain derivative with a saturated lactone ring, competes with 3H-ouabain for the binding to the two classes of sites. Binding to these two classes of sites appeared to be associated with a corresponding inhibition of (Na+ + K+)-ATPase activity.

The inotropic effect of ouabain and its antagonism by dihydroouabain in rat isolated atria and ventricles in relation to specific binding sites

The inotropic effect of ouabain has been studied in rat ventricles and atria. The concentration-effect curve of ouabain may be fitted by a model assuming the existence of two saturable components. The component with the higher sensitivity to ouabain accounted for 30% of the maximal increase in systolic tension in ventricles and for only 5% in atria. Increase in diastolic tension was only apparent at ouabain concentrations required to observe the low sensitivity component. [3H]-ouabain binding has been examined in microsomes prepared from atria and ventricles. High and low affinity binding sites have been observed. The ratio of high and low affinity ouabain binding sites was 4 fold lower in microsomes from rat atria than from rat ventricles. This could account for the difference in the response of these two tissues to the inotropic action of ouabain. In ventricular strips the high sensitivity component was much less apparent in the presence of dihydroouabain than with ouabain. When ventricular strips were preincubated in the presence of dihydroouabain 3 microM, the increase in systolic tension evoked by ouabain 1 microM was significantly reduced. Cumulative concentration-effect curve studies showed dihydroouabain antagonism to the high sensitivity component.

Anaesthesia for carotid body tumour resection. A case report and review of the literature

Anaesthetic management is described for the resection of a non-secreting carotid body tumour in a woman who had previously had a pneumonectomy. A brief review of the literature includes mention of some of the complications associated with the resection of carotid body tomours.

Treatment of gas gangrene. Interest of hyperbaric oxygen therapy

We report 27 cases of gas gangrene treated at the University Hospital of Liège since the Anesthesiology Department has been using a caisson for hyperbaric oxygen therapy. Frequency of gas gangrene does not appear to have decreased during recent years. The etiologies now encountered are mainly of post-traumatic and post-operative origin (especially surgery on the digestive tract); arterial insufficiency is a predisposing factor. The prognosis depends on the speed with which an effectual treatment is started; the latter consists in intensive hyperbaric oxygen therapy, antibiotic therapy and resuscitation. Surgery should be as conservative as possible and is undertaken only when progress of the disease has been checked by hyperbaric oxygen therapy. The association of these various modes of treatment proves effectual despite a still significant mortality.

BLOOD AMINO ACID STUDIES: I. A MIGROMETHOD FOR THE ESTIMATION OF FREE LYSINE, METHIONINE, AND THREONINE

By a modification of conventional methods of microbiological assay it was possible to determine the free lysine, methionine, and threonine in 0.2 ml of rat plasma. The small amounts of lactic acid produced in the microassay were estimated photometrically by measurement of the color change of bromthymol blue. Repeated analysis of samples on different days indicated no significant effect of days and the confidence limits for the assays were approximately ± 6% (p = 0.05). Mixtures of foods containing bread and various supplementary proteins were fed to young male rats for 24 hours and then plasma free lysine and methionine were measured. There was a direct relation between plasma free lysine levels and the lysine content of the diet. The method permits the accurate estimation of amino acids in blood of individual rats or in small samples of human plasma.