US-guided percutaneous biopsy: use of a screw biopsy stylet to aid needle detection

Insertion of a screw biopsy stylet into a thin-walled biopsy needle greatly enhances detection of the needle during ultrasound-guided percutaneous biopsy. This technique is helpful when precise needle-tip localization is needed for biopsies of small lesions.     

Pulmonary cystic disease: comparison of Pneumocystis carinii pneumatoceles and bullous emphysema due to intravenous drug abuse

A rare pulmonary manifestation of the acquired immunodeficiency syndrome or intravenous (IV) drug abuse is upper lobe cystic disease--pneumatoceles in Pneumocystis carinii pneumonia (PCP) and bullous emphysema in IV drug abuse. Because these disorders overlap, the radiographic findings in 56 patients were compared. During a 12-month period, 16 patients less than 40 years of age were found to have bullous emphysema; the 10 who were IV drug abusers constituted group 1. In the same time period, 40 patients with PCP were encountered; the eight (20%) who had or developed pneumatoceles constituted group 2. In both groups, the conventional radiographic manifestations of upper lobe cystic disease were similar. Eight patients underwent computed tomography of the chest. In five patients with bullous disease, the distribution of the bullous lesions was peripheral, with sparing of the central portions of the lungs. In contrast, PCP pneumatoceles in three patients were dispersed throughout the lung parenchyma.     

Epinephrine and phenylephrine increase cardiorespiratory toxicity of intravenously administered bupivacaine in rats

We studied the effects of epinephrine and phenylephrine on the cardiorespiratory toxicity of intravenously injected bupivacaine in Sprague-Dawley rats. Our data show that both epinephrine and phenylephrine significantly increased cardiorespiratory toxicity of intravenously injected bupivacaine (P less than 0.007, X2 analyses with Yates' correction). Our data suggest that epinephrine or phenylephrine added to bupivacaine may be more toxic to cardiorespiratory systems than plain bupivacaine or epinephrine alone or phenylephrine alone when injected intravenously in rats.     

Assent of school-age bilingual children

This article discusses the issue of assent of school-age bilingual children to participate in a research study. The article reviews cognitive, cultural, and linguistic factors influencing verbal and nonverbal concept formation in bilingual children. At the applied level, the focus of the article is on methodological considerations in using this information to obtain assent from a child who is bilingual and speaks English as a second language. Recommendations for the assessment of the child's language dominance, language proficiency, and the development of the assent form are provided. Language diversity and its potential effects on the assent process need to be formally acknowledged and appropriately addressed.     

Evidence for a role of endorphins in the cardiovascular pathophysiology of primate shock

Using the opiate receptor antagonist naloxone, we tested the hypothesis that endorphins act on opiate receptors to cause cardiovascular depression in primate shock. Mean arterial pressure (MAP), cardiac output, and left ventricular contractility (LV dP/dtmax) were measured in 34 anesthetized cynomolgus monkeys. Hemorrhagic shock was induced by bleeding into a heparinized reservoir to achieve (t = 0) and maintain MAP at 45 mm Hg. At t = 60 min, the reservoir was clamped and the animals were treated with 2 mg/kg plus 2 mg/kg.h naloxone (n = 5) or 0.9% NaCl as a control (n = 5). There were no significant differences in the cardiovascular responses to naloxone and saline when acid-base balance and core body temperature were not controlled. Pressor responses to naloxone, however, were present in proportion to arterial pH and body temperature. When these factors were controlled, naloxone (n = 6) significantly increased MAP and LV dP/dtmax by 48% and 83%, respectively, whereas saline (n = 6) had no significant effect. Blood was reinfused at t = 120 min, and survival rate at 72 h was significantly (p = .01) higher with naloxone (3/6) than saline controls (0/6). In the endotoxic shock model, cynomolgus monkeys were treated with 2 mg/kg plus 2 mg/kg.h naloxone (n = 6) or 0.9% NaCl (n = 6) when MAP reached 75 mm Hg or its nadir 60 to 90 min after Escherichia coli endotoxin, 5 mg/kg iv. Naloxone significantly increased MAP and LV dP/dtmax by 24% and 22%, respectively, whereas saline had no effect. Survival rate at 48 h was significantly (p = .01) higher with naloxone (6/6) than saline (1/6). Plasma beta-endorphin and beta-lipotropin concentrations rose three to five-fold in both shock models and were not affected by treatment. We conclude that endorphins are activated in primate shock and act on opiate receptors to contribute to the cardiovascular depression found with hemorrhage and endotoxemia.     

Arginine8-vasopressin reduces spinal cord blood flow after spinal subarachnoid injection in rats

Arginine8-vasopressin (AVP) causes hindlimb paralysis, loss of nociceptive responsiveness and increased arterial pressure after spinal subarachnoid injection in rats. In these experiments, the effects of paralytic intrathecal doses of AVP on rat brain and spinal cord blood flow, vascular resistance and cardiac output were measured using radiolabeled microspheres. Ten minutes after injection, AVP (10-100 pmol) elevated mean arterial pressures significantly, increased vascular resistances in thoracic and lumbosacral spinal cord and reduced blood flow to the lumbosacral spinal cord without altering cardiac output, total peripheral resistance and blood flow to brain and other spinal cord regions. Lumbosacral blood flows remained significantly reduced 30 min after injection of 100 pmol of AVP, and recovered to pretreatment base-line levels by 60 min postinjection. Lactic acid concentrations were elevated significantly in spinal cerebrospinal fluid samples removed 5 to 15 min after AVP injection (100 pmol). The selective AVP V1 receptor antagonist [1-(beta-mercapto-beta,beta-cyclopentamethylene propionic acid), 2-(O-methyl)tyrosine] arg8-vasopressin, which previously blocked the effects of AVP on hindlimb motor and nociceptive function, in these experiments also blocked the AVP-induced increases in arterial pressure and reductions in lumbosacral perfusion. Intravenous infusion of the vasodilators papaverine and nifedipine failed to block AVP-induced hindlimb paralysis. Nifedipine, however, did accelerate subsequent recovery of hindlimb motor function, although it did not alter the lumbosacral blood flow reductions measured at 10 and 30 min after AVP injection. These findings indicate that AVP has significant vascular effects in the rat spinal cord that are associated with ischemia and neurological dysfunction.(ABSTRACT TRUNCATED AT 250 WORDS)