Carbon dioxide-induced anxiety. Behavioral, physiologic, and biochemical effects of carbon dioxide in patients with panic disorders and healthy subjects

Carbon dioxide was administered for 15 minutes to patients with panic disorders (5% CO2, n = 14) and healthy subjects (5% CO2, n = 11; 7.5% CO2, n = 8). Following administration of CO2 and air placebo, changes in behavioral ratings, vital signs, and plasma levels of the norepinephrine metabolite 3-methoxy-4-hydroxyphenylglycol, cortisol, growth hormone, and prolactin were measured over three hours. In the healthy subjects, CO2 produced dose-related increases in anxiety, somatic symptoms, vital signs, and plasma cortisol levels. In the patients, the frequency of panic attacks (in eight of 14 patients) and the increases in anxiety and somatic symptoms induced by 5% CO2 exceeded those in the healthy subjects and were similar to those induced by 7.5% CO2 in the healthy subjects. The physiologic and biochemical measurements obtained did not elucidate the mechanisms underlying CO2-induced anxiety or the greater anxiogenic effects of CO2 seen in patients with panic disorders.     

The fetal auditory brain stem response: serial measurements at two stimulus intensities

Eleven fetal lambs were tested for auditory brain stem responses (ABRs) at 105 and 90 db sound pressure level from 110 to 116 days until 133 days gestation. ABRs were elicited in response to 1200 clicks, presented at 16 clicks/sec, from a hearing aid receiver secured in the fetal external ear canal and recorded from subdermal stainless steel electrodes at the vertex (active electrode) and anterior pinna (reference electrode). Six term newborn lambs were tested similarly for ABR comparison. No fetal ABRs appeared before 117 days gestation. Thereafter, the ABRs exhibited decreasing peak latencies with increasing stimulus intensity and fetal age. Newborn ABR latency measurements were compared with predicted newborn values generated from linear regression analysis of fetal data. Newborn latencies to waves I and II approximated predicted values. Newborn latencies to waves III, IV, and V were much shorter than predicted, suggesting rapid maturation of higher brain stem and midbrain neurogenerators during late fetal development.     

Stabilization of Red Blood Cells by the Plasticizer,Diethylhexylphthalate1

Abstract. The red blood cells of blood stored in containers made of polyvinylchloride (PVC) film are osmotically more stable and lose on average about 1/3 less hemoglobin than when blood is stored in another plastic [poly-(ethylene-co-ethyl acrylate); EEA]. The stability of uniform volumes of stored red blood cells varies directly with PVC surface area, whereas changes in EEA surface area have comparatively little or no effect. PVC contains high concentrations of the plasticizer, diethylhexylphthalate (DEHP), known to migrate into blood and to have a high potential for toxicity. To determine if DEHP could be the red cell stabilizing agent in PVC, whole blood was stored in containers made from EEA into which was incorporated varying amounts of DEHP. Incorporation of DEHP into EEA significantly reduced erythrocyte osmotic fragility (p = 0.01). The degree of reduced fragility correlated with the level of DEHP in the cell phase implicating DEHP in PVC containers as the stabilizing agent for red cells.     

Relationship of socialization and stress to perimenstrual symptoms, disability, and menstrual attitudes

This study examined the influence of socialization and exposure to a stressful milieu on perimenstrual symptoms, related disability, and menstrual attitudes. Women (N = 179) aged 18 to 35 were interviewed using the Index of Sex Role Orientation, Schedule of Recent Events, Moos Menstrual Distress Questionnaire, and Menstrual Attitudes Questionnaire, Path analysis was used to assess a model based on Mechanic's (1962, 1980) concept of illness behavior for negative affect, pain, and water retention symptoms during the perimenstruum. Exposure to a stressful milieu was useful in explaining cyclic, recurrent symptoms of negative affect. Of all the symptom clusters, negative affect was found to be the most important cause of perimenstrual disability. Traditional socialization, intense negative affect symptoms, and related disability all influenced menstrual attitudes.     

Effect of portocaval anastomosis on the incorporation of (U-14C)-D-glucose into protein, cholesterol, and lipid of rat brain

The incorporation of [U—¹⁴C]-D-glucose into lipid and protein of the brains of rats subjected to portocaval anastomosis has been studied from 2 to 20 weeks after the operation. It has been found that there is a reduction by about 30% of the labelling of protein, total lipid and of cholesterol in all experimental animals compared with controls. These findings are discussed in relation to the early astroglial disturbances after liver bypass and the later degenerative changes in terminal neurites that constantly occur in brain in this experimental preparation.     

Pathology of liver necrosis and regeneration after administration of dimethylnitrosamine in massive doses

Two groups of dogs were given dimethylnitrosamine (DMNA), a hepatotoxic drug, in a single lethal dose. Control dogs were allowed to die. Experimental dogs received life-saving auxiliary liver transplants which were removed after recovery of the host liver or when rejection occurred. The histopathologic findings in the host livers of the two groups are presented. Remarkable variations were noted even among livers from the same group. Centrilobular and midzonal congestion and necrosis were the main findings but appeared less severe than one would expect in view of the lethality of DMNA in control dogs. In contrast to the changes noted with long-term administration of the drug to dogs, there was nothing in this series to suggest cirrhosis.     

Benzodiazepine treatment of panic disorder: a comparison of alprazolam and lorazepam

The antipanic efficacy of alprazolam and lorazepam was evaluated in 48 patients meeting DSM-III criteria for agoraphobia with panic attacks or panic disorder in a double-blind random assignment study. On the basis of rating scale scores, both drugs demonstrated similar efficacy in reducing panic attacks and phobic behavior compared with placebo baseline. The doses required to achieve response were approximately double those required for the treatment of generalized anxiety. These results suggest that most, if not all, benzodiazepines may be effective antipanic drugs at high doses. The implications of these findings for drug treatments of choice for recurrent panic attacks are discussed.