Computer-assisted intravenous anesthesia: value, method and use

To assess whether vomitoxin-induced dysregulation of IgA production and IgA nephropathy are reversible, relevant immunologic parameters were compared among experimental groups of B6C3F1 mice that were fed: (1) 25 ppm vomitoxin in AIN-76A semipurified diet for 24 weeks (treatment group), (2) 25 ppm vomitoxin for 8 weeks and then control diet for 16 weeks (withdrawal group), and (3) control diet for 24 weeks (control group). Levels of serum IgA and microhematuria index in the treatment group were elevated after 4 to 8 weeks and continued to increase with further vomitoxin exposure. IgA immune complexes and mesangial IgA deposition, as quantitated by interactive laser cytometer image analysis, were also increased with toxin exposure at Weeks 8, 16, and 24, whereas IgM, IgG, and complement component C3 deposition were unaffected or depressed. Serum IgA, microhematuria index, and mesangial IgA deposition in withdrawal mice remained elevated over those of the controls at Weeks 16 and 24 but were less than those of the treatment group. Cell recovery from Peyer's patches (PP) as well as the percentages of IgA+ and CD4+ cells in PP and spleen at Weeks 16 and 24 were greater in treatment mice than in controls, but only the percentage of IgA+ cells in PP was elevated in the withdrawal mice at these the same time points. When IgA secretion by unstimulated and LPS-stimulated splenic lymphocytes was used as the measure of systemic production, it was elevated in both treatment and withdrawal mice at Weeks 16 and 24. The results indicated that experimental dysregulation of IgA production and IgA nephropathy persisted up to 4 months after a discrete period of dietary vomitoxin exposure, but that the severity of these effects did not increase in a progressive fashion.     

The use of a novel monitoring apparatus and modified Belzer hydroxyethyl starch perfusate for analysis of glomerular filtration during hypothermic perfusion preservation

The present study describes an experimental model for measurement of glomerular filtration during hypothermic perfusion preservation (HPP). To facilitate glomerular filtration during HPP, perfusate oncotic pressure was reduced by lowering the concentration of hydroxyethyl starch. Lewis rats underwent HPP at a mean perfusion pressure of 40-46 mmHg. An isograft model was used to demonstrate that retrieval and preparation for HPP did not impact adversely on renal function. Total cold ischemic time (CIT) consisted of the time from retrieval and preparation for perfusion (2 hr) added to the time of HPP. Tubular function studies demonstrated identical concentrations of Na+ and iohexol in ureteral effluent (UE) compared with circulating perfusate and, as such, established that UE flow represented a direct measure of glomerular filtration. Glomerular filtration rate (GFR) was then monitored during HPP by collecting UE in a beaker housed within a computerized Mettler balance system. GFR evolved in a characteristic, biphasic pattern during HPP, increasing from baseline values to reach a peak level at 4.8+/-0.3 hr of CIT and declining progressively thereafter. At 2.5 hr, time of peak values, 10 hr, 19.5 hr, and 24 hr of CIT, GFR values were 29+/-6 microl/min, 39+/-7 microl/min, 20+/-4 microl/min (n=15; P<0.01), 7+/-2 microl/min (n=14; P<0.001), and 14+/-6 microl/min (n=5), respectively. Intrarenal perfusate flows at the same time intervals were 4180+/-292 microl/min, 4083+/-290 microl/min, 3577+/-294 microl/min (P=NS), 1948+/-393 microl/min (P<0.001), and 2175+/-743 microl/min, respectively. Filtration fraction (FF) initially changed in parallel to glomerular filtration. Thereafter, FF either declined at a disproportionately slow rate compared with GFR (n=8) or increased rapidly (n=7). The data suggest that (1) primary change(s) in glomerular dynamics occur during HPP and (2) declining perfusate flow during the later stages of HPP reflects increasing renal vascular resistance localized at a postglomerular level. The data provide an experimental basis for investigating the clinical utility of monitoring glomerular filtration during HPP.     

The use of intravenous immunoglobulin in Miller Fisher syndrome

We report a patient with Miller Fisher syndrome who was treated with an intravenous high-dose of immunoglobulin. This syndrome is considered to be a benign variety of acute inflammatory demyelinating polyneuropathy (Guillain-Barré syndrome). However, there have been several reports of the need for ventilatory support and a few cases have had a fatal outcome. We observed a case of progressive Miller Fisher syndrome in a 3-year-old boy. Following 2 episodes of apnea lasting about 50 s each, he was treated with intravenous immunoglobulin (400 mg/kg/day) for 5 consecutive days. His respiratory state, general muscle strength, truncal ataxia and emotional state improved remarkably after this therapy.     

Endothelial cell compatibility of glycopeptide antibiotics for intravenous use

OBJECTIVE: The aim of this study was to evaluate the pulmonary CT findings in patients with Churg-Strauss syndrome to determine the frequency and nature of parenchymal abnormalities. MATERIALS AND METHODS: CT examinations performed at the time of diagnosis in 17 patients with Churg-Strauss syndrome were retrospectively evaluated by two observers who reached a decision by consensus about the presence and nature of parenchymal abnormalities. High-resolution CT (1- to 3-mm collimation) was performed in 14 patients and conventional CT (6- to 10-mm collimation) was performed in three cases. RESULTS: Predominant CT findings consisted of parenchymal opacification (consolidation or ground-glass attenuation) (n = 10), pulmonary nodules (n = 2), bronchial wall thickening or dilatation (n = 2), interlobular septal thickening (n = 1), and normal anatomy (n = 2). Parenchymal opacification was predominantly peripheral (n = 6) or random in distribution (n = 4). CONCLUSION: The most common CT finding in patients with Churg-Strauss syndrome consists of areas of parenchymal opacification that may be random or peripheral in distribution. These findings are nonspecific.     

The effect of vascular perfusion fixation on the ultrastructure of the juxtaglomerular apparatus of the rat

After fixation by low pressure retrograde perfusion the electron microscopic picture of the rat JGA was studied and compared with the picture obtained after fixation by dripping and immersion. The most conspicuous difference was the presence of the basal compartments of the macula densa cells, which might land electron microscopic support to the tubulo-glomerular feedback theory. Among the JG granular cells, desmosome-like connected structures were seen. Crystalline and granule in granules specific secretion forms were frequent in the epitheloid cells.     

Dexamethasone perfusion of the labyrinth plus intravenous dexamethasone for Ménière's disease

Recent clinical and laboratory evidence indicates that Meniere's disease is an immune-mediated disease. Dexamethasone perfusion of the inner ear through the round window plus intravenous dexamethasone often will stop the dizzy spells, reduce the fullness and low-frequency tinnitus, and sometimes improve the hearing in patients with Meniere's disease. The dexamethasone must act mostly on the endolymphatic sac and, to a lesser extent, on the stria vascularis and spiral ligament, the known targets of immune response in the inner ear, to reduce the endolymphatic hydrops and restore the fluid dynamics of the endolymph. Despite the good results with streptomycin perfusion, the number of patients with further hearing loss is large, so dexamethasone perfusion with intravenous dexamethasone should be tried first. The initial response to dexamethasone perfusion plus intravenous dexamethasone has been very good, with very little risk of further hearing loss, and it holds great promise for the future.     

The concentration of responsibility: An objective self-awareness analysis of group size effects in helping situations.

On the basis of the Gestalt figure-ground principle, an objective self-awareness theory interpretation of group size effects in helping situations was proposed. From this perspective, the diffusion of responsibility effect commonly observed in helping research is the decreasing likelihood of bystander objective self-awareness, and hence bystander intervention, that accompanies increases in the size of the bystander group. A complementary concentration of responsibility hypothesis derived from this analysis states that an increasing likelihood of bystander objective self-awareness, and therefore of bystander aiding behavior, is associated with increases in the size of the victim group. An experiment with 48 undergraduates tested this hypothesis in a 2–2 design varying number of potential helpers (1 vs 3) and number of victims (1 vs 3). Results show that straightforward appeals for help were more likely to be met with assistance when there were fewer potential helpers or more victims; thus, both the diffusion and concentration of responsibility were observed. Ratings of attentional focus obtained from 126 observer-Ss in a simulation of this experiment further substantiated the contention that these effects are attributable to variations in self-focused attention experienced by potential helpers. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Immunoglobulins for intravenous use inhibit TNF alpha cytotoxicity in vitro

Intravenous immunoglobulins (IVIg) have been used as an immunomodulatory therapy in a variety of diseases. Several mechanisms of action have been proposed, one of which is interference with the cytokine network. We have investigated the effect of IVIg on the cytotoxicity of human TNF alpha. IVIg was capable of protecting L929 fibroblasts from TNF alpha induced cell death. This effect was not species specific and was mediated by both the Fc and the Fab portion of immunoglobulins. Since the effect was also seen when IVIg was added after the removal of TNF alpha from the culture medium, it seems to be independent of the interaction of TNF alpha with its receptor. We conclude that IVIg either act on some point of the TNF alpha signalling pathway or influence the cell cycle unspecifically. The cytoprotective effect of IVIg potentially could contribute to the beneficial effect described for various diseases.     

Indications for the use of magnesium in anesthesia and intensive care

Magnesium (Mg), a cofactor in numerous enzymatic reactions, is often ignored by clinicians, as the symptomatology of Mg depletion is not specific and usually associated with that of the cause of the depletion. Furthermore, the plasma Mg concentration (0.8 to 1.1 mmol.L-1) is only equivalent to one percent of the total body content. A Mg deficit may exist while plasma Mg concentration is normal. Therefore other techniques for Mg assessment, such as the repletion test, as well as red blood cell and lymphocyte concentrations have been used. A renewed interest for Mg occurred as numerous studies have shown the therapeutic efficiency of Mg and as the mechanisms of its haemodynamic effects have been recognized. Mg regulates Na-K-ATPase activity, K channels activity and, most of all, it is a natural calcium channel blocking agent. These properties explain its important place in electrophysiology of myocardial cells and the effects on the tension of smooth muscles, resulting in a vasodilation and a bronchodilation respectively. The antagonistic effect of Mg on calcium decreases the presynaptic release of acetylcholine at the neuromuscular junction and the release of epinephrine at the peripheral sympathetic nerves and the adrenals. Mg potentiates the effect of non-depolarizing muscle relaxants. A Mg deficiency occurs often in ICU patients, in alcoholics and during use of diuretics. Simultaneous administration of Mg is often required for treatment of potassium deficiency. Mg has an anti-arrhythmic effect towards digoxin-mediated dysrhythmias and torsades de pointes, and can be efficient in other arrhythmias. Systematic use of Mg seems to decrease mortality of acute myocardial infarction and is justified during cardiac surgery, often associated with hypomagnesemia, because of vasodilation of coronary arteries and in order to prevent occurrence of arrhythmias. Mg, because of its calcium channel blocking properties and as it lowers the release of epinephrine, is indicated for surgery of pheochromocytoma. In eclamptic and pre-eclamptic patients, the use of Mg is valuable, but not as an anti-epileptic agent. Other clinical uses of Mg have been proposed, but they are either anecdotal or of uncertain efficiency.     

Clinical use of etomidate for anesthesia induction: a preliminary report

Etomidate (0.3 mg/kg) and thiopental (4 mg/kg) were administered IV for induction of general anesthesia, comparing heart rate, blood pressure, respiration, and side effects. No significant difference between the drugs was found in the circulatory parameters, but respiration was more depressed by thiopental. A high incidence of the side effects of myoclonia and pain on injection was seen with etomidate. The incidence of side effects was not affected by speed of injection or type of premedication. Mechanisms to reduce the incidence of side effects are needed for etomidate to become a useful induction agent.     

全凭静脉麻醉下脑电双频谱指数监测在术中知晓预防中的作用

目的:探讨全凭静脉麻醉下应用脑电双频谱指数(BIS)监测术中知晓的发生情况,评价BIS监测对术中知晓的预防作用.方法:丙泊酚全凭静脉麻醉下行择期手术患者300例,随机分成A、B两组(n=150).两组患者均进行BIS监测,A组根据BIS值调控麻醉深度,确保麻醉期间BIS值<60;B组术中遮蔽BIS值,根据经验调控麻醉深度.记录两组患者麻醉诱导、手术开始、麻醉停药、手术结束、麻醉苏醒、拔管时BIS值及术中知晓的发生情况.结果:两组患者基础BIS值、诱导结束时、清醒时及拔管时BIS值比较差异无统计学意义(P>0.05),手术开始时、麻醉维持和麻醉结束时BIS值比较差异有统计学意义(P<0.05).A组无知晓病例及怀疑知晓病例.B组无知晓病例,但存在2例怀疑知晓病例,2组怀疑知晓率比较差异有统计学意义(P<0.05).结论:全凭静脉麻醉时采用BIS监测能够维持合适的麻醉深度,预防术中知晓的发生.     

Prospects of the use of caudal epidural anesthesia

Caudal epidural anesthesia for interventions on the lower limbs and pelvic organs was used in 525 patients. A specific feature of the method is use of hypoosmolic local anesthetic solution (osmolality 260 mosmol/kg) containing lidocaine, 0.9% sodium chloride, and distilled water. Pathologic studies showed that in adult patients, at least 40 ml anesthetic should be injected into the caudal canal for adequate blocking. During surgery, caudal epidural anesthesia reliably protected from surgical trauma without side effects for respiration and circulation. The duration of analgesic effect was 3 +/- 0.5 h and even longer, if local anesthesia was potentiated with sedative drugs. No complications were observed, failures occurred in 5.2% cases. The method is simple and reliable and is recommended for practice.     

Rhabdomyolysis associated with the use of intravenous vasopressin

A patient with acute esophageal variceal bleeding developed fatal rhabdomyolysis during treatment with a continuous intravenous infusion of vasopressin. Signs of ischemia, including mottling of skin and painful extremities, preceded the development of the characteristic electrolyte abnormalities and cardiac arrhythmias. No other recognized causes of rhabdomyolysis were identified on retrospective review of the hospital course. There are several factors which might promote a peripheral ischemic response to vasopressin in the bleeding cirrhotic patient, including altered resting hemodynamics, increased resting sympathetic tone, impaired vasodilation as a compensatory response to vasopressin, and reduced hepatic drug clearance. Idiosyncratic factors involving vasopressin receptor affinity and distribution, vasopressin-associated vasodilation in some vascular beds, and the effect of vasopressin on the renin-angiotensin system may further contribute to impaired tissue perfusion. These multiple overlapping factors probably lead to rhabdomyolysis in a minority of patients receiving vasopressin infusion.     

Determinants of condom use among intravenous drug users

OBJECTIVE: To examine the factors associated with condom use among a cohort of sexually active intravenous drug users (IVDU). DESIGN: Data were collected via personal interview at the fourth-month assessment point of a longitudinal study monitoring HIV infection and risk behaviors among IVDU. SETTING: A community-based methadone clinic. PARTICIPANTS: A total of 158 sexually active heterosexual male and female IVDU, including both methadone patients and out-of-treatment individuals with a history of opiate abuse. MAIN OUTCOME MEASURES: We describe a new approach to identify the determinants of condom use. Previous studies have described subjects as either 'condom users' or 'condom non-users', using an individual's overall behavior as the unit of analysis. By analyzing condom use during the most recent sexual encounter, we avoided the problem of interpreting inconsistent condom use. Data were analyzed using forward stepwise logistic regression. RESULTS: Thirty-four per cent of the heterosexual subjects (n = 160) reported using a condom during their last sexual encounter. Being HIV-positive and having either a causal or commercial partner were each associated with increased probability of using a condom (odds ratio, 10.6, 4.4 and 12.1, respectively). No interactions with sex were found. CONCLUSIONS: Our results suggest that knowing that one is HIV-positive is an important determinant of condom use; HIV testing may therefore increase the use of condoms. In addition, interventions to change sexual behaviors may need to focus on the type of sexual partner.