Attentional modulation of the cardiac defense response in humans

How cardiac components of the defense reaction are modulated by attentional factors related to sensory intake versus sensory rejection was examined. Forty-eight men participated in a test of the heart rate response to three presentations of an intense auditory stimulus while performing one of three attentional tasks during the 80 s following stimulus onset: (a) internal (rejection) task, (b) external (intake) task, and (c) no task. Results showed a potentiation of the defense response only under the external attention condition. We concluded that defensive reactions, far from provoking the rejection of the aversive stimulus, require allocation of attention to processing that stimulus in detail.     

THE EFFECT OF NICOTINIC ACID ON THE DEPRESSANT ACTION OF ETHANOL AND PENTOBARBITAL

The effect of nicotinic acid (NA) on sleeping time induced bya single dose of ethanol or pentobarbital was studied in rats.It was found that sleeping time was markedly reduced by NA ina dose-dependent manner. The effect was observed when NA wasadministered 10 min before or after ethanol or pentobarbital,but not when given 60 min in advance. NA did not affect therate of ethanol elimination measured up to 5 hr after ethanoladministration. Rats pretreated with NA 60 min before ethanolslept longer than controls. This latter effect was not observedwith pentobarbital. These observations, together with the knownlack of effect of high liver NAD⁺ levels on ethanol metabolismand the rather stable NAD⁺ concentration in brain cells, suggestthat the effect of NA on sleeping time is not mediated by anincrease in ethanol metabolism in liver or by NAD⁺ or NAD⁺-dependentreactions in brain. Our results are consistent with a directaction of NA, or some rapidly formed derivative, on a structureor process associated with brain cell functions or membranes.     

ALCOHOL DEHYDROGENASE FROM HUMAN STOMACH: VARIABILITY IN NORMAL MUCOSA AND EFFECT OF AGE, GENDER, ADH3 PHENOTYPE AND GASTRIC REGION

Alcohol dehydrogenase (ADH) has been analysed in 36 endoscopicbiopsies of normal gastric body and/or antrum mucosa, from 31individuals with an age between 17 and 79 years. Oesophageal,duodenal and oral mucosa specimens have been also examined.Stomach mucosa contains three isozyme types: the     

Successful Rotational Atherectomy of Mid-Saphenous Vein Graft Lesions

Rotational atherectomy has long been regarded as contraindicated for stenotic lesions within the body of saphenous vein grafts. So far, reports of rotational atherectomy in vein grafts have been concerned with ostial and distal anastomotic lesions. We report the first two cases of the successful use of the Rotablator for discrete lesions of mid-saphenous vein grafts. No complications were encountered. One patient is doing well 6 months after the procedure, and the other patient continues to do well more than 1 yearlater.     

Effects of chronic oestrogen treatment are not selective for uterine noradrenaline-containing sympathetic nerves: a transplantation study

Previous studies have shown that chronic administration of oestrogen during postnatal rat development dramatically reduces the total content of noradrenaline in the uterine horn, abolishes myometrial noradrenergic innervation and reduces noradrenaline‐fluorescence intensity of intrauterine perivascular nerve fibres. In the present study we analysed if this response is due to a direct and selective effect of oestrogen on the uterine noradrenaline‐containing sympathetic nerves, using the in oculo transplantation method. Small pieces of myometrium from prepubertal rats were transplanted into the anterior eye chamber of adult ovariectomised host rats. The effect of systemic chronic oestrogen treatment on the reinnervation of the transplants by noradrenaline‐containing sympathetic fibres from the superior cervical ganglion was analysed on cryostat tissue sections processed by the glyoxylic acid technique. In addition, the innervation of the host iris was assessed histochemically and biochemically. The histology of the transplants and irises was examined in toluidine blue‐stained semithin sections. These studies showed that after 5 wk in oculo, the overall size of the oestrogen‐treated transplants was substantially larger than controls, and histology showed that this change was related to an increase in the size and number of smooth muscle cells within the transplant. Chronic oestrogen treatment did not provoke trophic changes in the irideal muscle. Histochemistry showed that control transplants had a rich noradrenergic innervation, associated with both myometrium and blood vessels. Conversely, in oestrogen‐treated transplants only occasional fibres were recognised, showing a reduced NA fluorescence intensity. No changes in the pattern and density of innervation or in the total content of noradrenaline of the host irises were detected after chronic exposure to oestrogen. We interpreted these results to indicate that the effects of oestrogen on uterine noradrenaline‐containing sympathetic nerves are neither selective or direct, but result from an interaction between sympathetic nerve fibres with the oestradiol‐primed uterine tissue. A potential effect of oestrogen on the neurotrophic capacity of the uterus is discussed.     

Wide QRS Complex Arrhythmia with Alternating QRS Morphology: What Is the Mechanism?

A 75‐year‐old man was admitted due to an electrical storm with appropriate recurrent implantable cardioverter defibrillator (ICD) discharges. The patient had had an extensive anterolateral myocardial infarction with associated severe left ventricular dysfunction 10 years earlier (left ventricular ejection fraction, 25%), and an ICD was placed 9 years before admission for primary prevention of sudden cardiac death. A first invasive study induced up to five ventricular tachycardias and an extensive endocardial substrate ablation was performed. Despite intravenous β‐blockers, general anesthesia and procainamide infusion, the patient continued to have recurrent episodes of very slow sustained ventricular tachycardia with a right bundle branch block pattern. In a subsequent invasive study, no mid‐diastolic activity was found despite careful mapping during the induced clinical ventricular tachycardia and ablation attempts inside the apical endocardial scar were unsuccessful. A percutaneous epicardial approach with navigation system support (EnSite Precision^TM Cardiac Mapping System v. 2.0, St. Jude Medical, St. Paul, MN, USA) without antiarrhythmic infusion was planned. A wide QRS complex rhythm with alternating QRS morphology was readily induced by epicardial ventricular pacing trains (Fig. 1, top) that elicited both arrhythmia QRS patterns with very long stimulus QRS intervals (Fig. 1, bottom). What is the possible mechanism of this arrhythmia? Do we need further pacing maneuvers during the arrhythmia to localize critical sites at which ablation pulses can predictably be successful?