Synaptosomal Na, K-ATPase during forebrain ischemia in Mongolian gerbils

We studied the activity and kinetic parameters of synaptosomal Na, K-ATPase during 15 min of forebrain ischemia and following 60 min of reperfusion produced by reversible common carotid occlusion in Mongolian gerbils. A synaptosomal fraction was obtained by both differential centrifugation of brain tissue homogenate and centrifugation of crude mitochondrial fraction at a discontinual sucrose density gradient. We found two components of ATP concentration dependence of ATP hydrolysis that represent two types of ATP-binding sites: high affinity and low affinity. Neither ischemia nor reperfusion affected kinetic parameters of a high-affinity site. However, lowaffinity site parameters were affected by both ischemia and ischemia followed by reperfusion. Maximal velocity (V _max) decreased by 43 and 42% after ischemia and after ischemia/reperfusion, respectively. The apparentK _m for ATP decreased by 52% after ischemia and by 47% after ischemia/reperfusion. The apparent affinities for K⁺ and Na⁺ were determined from the ATP hydrolysis rate as a function of Na⁺ and K⁺ concentrations. We found the half-maximal activation constant for K⁺ (K _a K⁺) increased by 60% after ischemia and by 146% after ischemia/reperfusion. On the other hand, we found thatK _aNa⁺ decreased significantly after ischemia/reperfusion (16%). We concluded that it is the dephosphorylation step of the ATPase reation cycle that is primarily affected by both ischemia and ischemia/reperfusion. This might be caused by alteration of the protein molecule and/or its surroundings subsequent to ischemia.     

时滞系统鲁棒稳定性的新判据

基于Ｌｙａｐｎｕｏｖ泛函方法，研究了满足匹配条件的不确定性时滞系统的鲁棒稳定性及具有稳定度β〉０鲁棒稳定性，给出了已有结果不能推出的新判据。这些新判据对已有结果难以使用的情况下也可有是有效的，或有时减少了已有结果的保守性。     

Choosing a career in general practice: the influence of medical schools

Summary. This paper reviews the literature on career choice to investigate the undergraduate influences on the preference of Australian graduates for a career in general practice. Although isolation of influencing factors is difficult, admission criteria and undergraduate curricula may influence career preference. As the institutional environment of medical schools is weighted towards scientific research and specialized medicine, medical students may be socialized into choosing non-generalist careers. Medical schools should consider broadening selection criteria and curriculum exposure to produce graduates with a broad range of career interests.     

Characteristics of antibody responses induced in mice by protein allergens

Whereas many foreign proteins are immunogenic, only a proportion is also allergenic, having the capacity to induce the quality of immune response necessary to support the production of IgE antibody. We have demonstrated previously that intraperitoneal administration to mice of proteins such as ovalbumin (OVA) or the industrial enzyme A. oryzae lipase, which possess significant allergenic potential, stimulates the production of both IgG and IgE antibody. Identical exposure to bovine serum albumin (BSA), a protein with limited potential to cause immediate respiratory or gastrointestinal hypersensitivity reactions, induced IgG responses only. In the current investigations, the quality of immune responses induced following exposure to these proteins via mucosal tissue (intranasal) has been compared with those provoked following administration via a non-mucosal (intraperitoneal) route of exposure. Intranasal or intraperitoneal administration of BSA, OVA or A. oryzae lipase elicited in each case vigorous IgG and IgG1 antibody responses. For all three proteins, at every concentration tested, and via both routes of exposure, IgG1 antibody titres paralleled closely IgG titres. However, the three materials displayed a differential potential to provoke IgE responses and this correlated with their known allergenic potential in humans. Thus, OVA and A. oryzae lipase stimulated strong IgE antibody responses, whereas BSA provoked low titre IgE only at the highest concentration tested (5% administered intraperitoneally). The quality of induced responses was not affected by the route of exposure. It would appear, therefore, that the stimulation of IgG and IgG1 antibody responses is a reflection of protein immunogenicity whereas protein allergenicity is associated with the induction of strong IgE responses.     

复方丹参注射液与维生素B6、C注射液配伍稳定性试验

本文观察了复方丹参注射液与维生素B6、维生素C注射液的配伍稳定性，结果表明复方丹参注射液与维生素B6注射液可以在4h内配伍使用，而不能与维生素C配伍。     

Partial splenic embolization for hypersplenism concomitant with or after arterial embolization of hepatocellular carcinoma in 30 patients

Purpose To study the value of partial splenic embolization (PSE) for the treatment of hypersplenism in patients undergoing embolization of hepatocellular carcinoma (HCC). Methods Transcatheter hepatic arterial embolization (THAE) combined with PSE was performed in 30 patients with HCC complicating liver cirrhosis, portal hypertension, and hypersplenism. Gelfoam sponge was used as the embolic material for PSE and limited to 100–150 pieces. Results More than 50% of splenic parenchyma was infarcted in 27 patients. Leukopenia and thrombocytopenia were corrected by PSE in 25 of 27 patients with hypersplenism. In 26 patients with esophageal varices, including 5 patients with bleeding, no rebleeding occurred during a 6–17 month follow-up. Hypersplenism was not corrected in 2 of 3 patients whose infarcted splenic parenchyma was less than 50%. No splenic abscesses or other severe complications were observed. Of the 30 patients treated, 19 are still alive after 1 year. Conclusions THAE combined with PSE is a safe and effective measure for patients with HCC.     

Evaluation of loose bodies in the elbow with MR imaging

The evaluation of loose bodies in the elbow is usually done by means of clinical examination, radiography, and postarthrographic computed tomography (CT). The authors review their experience with magnetic resonance (MR) imaging in place of postarthrographic CT for the evaluation of loose bodies in the elbow. The prospective interpretation of MR studies of the elbow in 20 patients was compared with arthroscopic findings. All elbows were imaged in multiple planes with thin sections, surface coils, and combinations of T1, T2, and proton-density weighting. The sensitivity for showing loose bodies with MR imaging was 100%, and the specificity was 67%. Because this was a nonblinded study, the results are biased and caution must be used when extrapolating these results to the general population. In this limited experience, MR imaging has reliably shown loose bodies in the elbow, and in the authors' institutions has replaced postarthrographic CT for that purpose.     

Dixyrazine premedication for cataract surgery. A comparison with diazepam

Peroral dixyrazine (15–30 mg, n = 50) and diazepam (4–10 mg, n = 50) were used as premedicants for geriatric patients having cataract surgery under regional block. Compared to the diazepam patients, a larger number of the dixyrazine medicated patients appeared anxious, and there was a statistically significant difference between the groups, when summing up changes in anxiety throughout the study period. The dixyrazine patients needed more frequent supplementation with intravenous sedative drugs, compared with their diazepam counterparts. Peroral dixyrazine is an applicable choice for calm patients, when only slight sedation, or avoidance of somnolence are required.     

Changes in the Amphibian Antibody Repertoire are Correlated With Metamorphosis and not With Age or Size

Tadpole and adult Xenopus, manipulated to be of comparable size, exhibited stagespecific antibody expression. The production of adult-type higher-affinity anti-DNP antibodies proved to be independent of the age and size of the individual and is concomitant with the completion of metamorphosis. The appearance of new antibody specificities at such a time suggests that their expression occurs with the cell turnover and renewal during a period of morphological changes.     

Acute hemodynamic responses to electroconvulsive therapy are not related to the duration of seizure activity

Study Objective: To test the hypothesis that the magnitude of the acute hemodynamic response to electroconvulsive therapy (ECT) is related to the duration of the seizure activity in patients receiving different dosages of intravenous (IV) lidocaine.

Design: Randomized, double-blind, placebo-controlled, cross-over study.

Setting: University-affiliated hospital.

Patients: 21 ASA physical status I, II, and III patients undergoing four consecutive maintenance ECT treatments for chronic depression.

Interventions: Patients received lidocaine 50 mg, 100 mg, 200 mg IV, or saline prior to induction of anesthesia via a standardized anesthetic technique.

Measurements and Main Results: Noninvasive blood pressure (BP) and heart rate (HR), as well as the duration of motor and electroencephalographic (EEG) seizure, were measured. The duration of motor and EEG seizures (means ± SD) were 37 ± 13 sec and 64 ± 21 sec, 25 ± 11 sec and 52 ± 43 sec, 17 ± 12 sec and 32 ± 17 sec, 1 ± 3 sec and 18 ± 10 sec in the saline, lidocaine 50 mg, 100 mg, 200 mg groups, respectively. Although the duration of seizure activity was decreased in a dose-related fashion after lidocaine pretreatment, the peak increases in BP and HR were similar in the lidocaine and saline treatment groups.

Conclusions: Despite producing dose-related decreases in the duration of both motor and EEG seizure activity, lidocaine failed to attenuate the acute hemodynamic response to ECT. Thus, the acute hemodynamic response to ECT is not related to the duration of seizure activity.