The effects of cholinergic compounds on the development of morphine tolerance, dependence and increased naloxone potency in mice

The effects of chronic treatment with morphine and cholinergic compounds on the development of morphine tolerance, physical dependence and increased naloxone potency were studied. Using the abdominal constriction method, it was shown that morphine tolerance was apparent after s.c. administration of morphine 20.0 mg/kg three times a day for four days. It was found that, in animals which showed a low degree of morphine tolerance, the naloxone potency was similar to that determined in mice which had been pretreated with only a single dose of morphine which causes no measurable tolerance. Thus, the development of increased naloxone potency and tolerance to morphine do not parallel each other. In addition, while atropine inhibited, and anti-cholinesterase drugs enhanced, the development of increased naloxone potency caused by morphine treatment they had no or little effect on the development of morphine tolerance. Furthermore, chronic treatment with cholinergic agonists reduced, while muscarinic antagonist enhanced, the development of physical dependence on morphine as assessed by withdrawal jumping and body weight loss. It is concluded that the increased potency of naloxone in antagonising the antinociceptive effect of morphine can be dissociated from the development of tolerance to, and physical dependence on, morphine in mice.     

Residual effects of food deprivation on food consumption and runway performance in the satiated rat.

2 experiments studied the residual effects of prior food deprivation in 35 female and 28 male Holtzman rats as measured by probability to eat and acquisition of a running response under satiated conditions. Although the effects were positively related to the severity of prior deprivation (Exp II), a drive-conditioning interpretation was questioned because of 3 findings: (a) effects were not dependent on exposure to the test situation when Ss were deprived (Exp I and II); (b) prolonged testing during satiation increased rather than decreased the effects (Exp I and II); and (c) the instrumental response decreased only when reward was withheld (Exp I). (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Theory of the frequency responses of uniform and quasi-taper helical antennas

A theory is presented for the frequency responses of uniform and quasi-taper helical antennas radiating in the axial mode. Based on a model assuming a single traveling wave of current, expressions for the far-zone electric field are obtained by summing the contributions of the current elements from one end of the helix to another. These expressions are used to study the variation of the axial electric field with frequency, first assuming the Hansen-Woodyard (HW) condition and then assuming Sensiper's solution for the phase velocity. It is found that the HW condition leads to the result that the electric field increases monotonically with frequency over the entire axial mode range, which is in violation with the recent experimental measurements of King and Wong. On the other hand Sensiper's phase velocity yields frequency response curves that are consistent with King and Wong's measurements. Numerical results are given for uniform helices and quasi-taper helices consisting of two uniform sections of different diameters.     

Hepatic resection for hepatolithiasis

OBJECTIVE: To analyze the results of hepatic resection for hepatolithiasis. DESIGN: A retrospective study of case records of patients with hepatolithiasis undergoing hepatic resection. These patients had been followed up for 3 to 38 months. They were referred to Queen Mary Hospital, a tertiary referral center in Hong Kong. PATIENTS: Of 172 patients with hepatolithiasis seen between January 1984 and December 1981, 63 patients underwent hepatic resection because the affected liver segments were destroyed by repeated infection (n = 51), multiple cholangitic liver abscesses were found in the affected liver segments (n = 9), or concomitant intrahepatic cholangiocarcinoma was diagnosed (n = 3). INTERVENTION: Left lateral segmentectomy was performed in 42 patients, left hepatic lobectomy in 15 patients, right hepatic lobectomy in one patient, and segmentectomy in five patients. MAIN OUTCOME MEASURES: Postoperative morbidity and mortality analysis. RESULTS: Contrary to hepatic resection in a normal liver, dissection to isolate inflow and outflow vasculature was difficult in 52% of cases owing to severe inflammatory fibrosis at the liver hilum, at the umbilical fissure, or at the junction of hepatic vein with inferior vena cava. The operative morbidity rate was 32% and the mortality rate was 2%. The majority of complications were wound infection, subphrenic abscesses, or biliary fistulas, which could be due to the presence of infected bile (85%) and liver abscesses (25%) in this disease. Statistical analysis of the preoperative hematological and biochemical variables and the amount of intraoperative blood loss could not identify any factor with significance in correlating with the development of postoperative complications. Stones recurred in 16% after a median follow-up of 47 months. CONCLUSION: Hepatic resection is a satisfactory treatment for hepatolithiasis. The postoperative septic complication rate is high and is an intrinsic problem related to liver resection in a septic condition.     

Cloning and overexpression of rhamnose isomerase and fucose isomerase

Rhamnose isomerase and fucose isomerase were overexpressed in E. coli, purified and characterized. The rhamnose isomerase gene was ligated to the restriction sites of PstI and Hind III of vector pTrcHis and the fucose isomerase gene was ligated to the EcoRI and PstI sites of vector pKK223-3 for overexpression of the enzymes in E. coli XL1-Blue MRF. Approximately 16,500 U of active fucose isomerase and 2400 of rhamnose isomerase can be obtained per liter of culture from these expression systems.     

A new framework for part failure-rate prediction models

This paper presents a framework for developing part failure-rate models. It is a partial result of an effort sponsored by the US Air Force for the development of reliability prediction models for military avionics. Published data show that the existing reliability prediction methods fall far short of providing the required accuracy. One of the problems in the existing methods is the exclusion of critical factors. The new framework is based on the premise that essentially all failures are caused by the interactions of built-in flaws, failure mechanisms, and stresses. These three ingredients contribute to form the failure distribution which are functions of stress application duration (eg, aging time), number of thermal cycles, and vibration duration. The Weibull distribution has been selected as the general distribution. The distribution is then modified by the critical factors such as flaw quantities, effects of environmental stress screening, calendar-time reliability improvements, and vendor quality differences, to provide the part failure-rate functions. To provide credibility for the framework, only well published data and information have been used     

Step-up DC power supply based on a switched-capacitor circuit

A new step-up DC-to-DC power converter with high power density is presented. It contains no inductors or transformers. The controlled energy transfer from an unregulated voltage source to a regulated output voltage is realized through a switched-capacitor circuit. The operation of the switches in the power stage is dictated by a PWM-type feedback circuit. The new regulator is simulated by using an averaged state-space approach. The transient and steady-state waveforms, as well as the AC small-signal input-to-output and control-to-output transfer functions are obtained by both simulation and experiments. The power supply, implemented for a nominal power of 15 W, and input-to-output voltage ratio of 5/12, features high efficiency for this class of powers, small output voltage ripple, continuous input current, low weight and small size     

利用中颗粒热释光进行古陶鉴证的尝试

采用中颗粒（φ１０—３０μｍ）制样进行了陶器的年龄测定．对１５个标本同时以细颗粒样品和中颗粒样品做实验，两组结果一致．中颗粒的自然热释光强度高于细颗粒．     

Statewide assessment of school-age children with asthma in Delaware

In Delaware, asthma affects almost 14,000 children. The American Lung Association of Delaware and the University of Delaware surveyed school nurses to identify the needs of children with asthma and the services and accommodations available for these children. Researchers developed a survey instrument that was mailed to all Delaware schools (N = 324). The response rate was 38.6% (n = 125). According to respondents, a variety of protocols were in place regarding the administration of asthma medications. Respondents also reported that several measures had been taken to modify the school environment to improve air quality and reduce asthma triggers. Most respondents (77%) indicated they did not have asthma education programs in their schools. Findings from this study sparked development of a multidisciplinary Delaware Asthma Committee, an Asthma Education Center, and a statewide system for communicating with the parents of children with asthma.