Effects of test conditions on the outcome of place conditioning with morphine and naltrexone in mice

BACKGROUND: Although it is widely proposed that surgeons, before introducing a novel laparoscopic technique in man, should practice in an appropriate animal model for acquisition of the necessary technical skills, the effectiveness of those hands-on training courses are rarely documented. METHODS: In 1995 we have organized eight hands-on training courses for laparoscopic anterior interbody spine fusion in an in vivo porcine model. A total of 72 colleagues from 50 different centers of 12 countries participated, including orthopedic, trauma, visceral, neuro-, and vascular surgeons. Quality and effectiveness of the course were evaluated by a questionnaire after a 1.5- to 2.5-year period. RESULTS: During this time, 42.2% of the participating centers had applied the new technique successfully in man. Centers which participated in the course with a team that included a skilled laparoscopic surgeon and an orthopedic or trauma surgeon introduced the technique more frequently to clinical practice (57.9%) than those represented by only one participant (30. 8%). Moreover, there was a tendency toward a more frequent introduction of the technique to clinical practice in centers associated with university hospitals (57.1% vs. 29.2%), indicating the requirement of a particular infrastructure for this complex interdisciplinary procedure. Almost all participants (98.3%) agreed that for novel surgical techniques requiring advanced technical skills, there should first be training in a large animal model before the technique is applied in man. CONCLUSIONS: Complex laparoscopic procedures (i.e., laparoscopic spine surgery) can be successfully learned by in vivo hands-on training courses. We propose that for refinements and modifications of the technique (e.g. , the lumboscopic approach), there should also first be training in a large animal model before these are applied in man.     

A motor neuron-specific epitope and the low-affinity nerve growth factor receptor display reciprocal patterns of expression during development, axotomy, and regeneration

Somatic motor neurons begin to express the transmitter synthesizing enzyme, choline acetyltransferase (ChAT) and the low-affinity nerve growth factor receptor (NGFR) during embryonic development. However, as motor neurons mature in postnatal life, they lose immunoreactivity for NGFR and acquire a motor neuron-specific epitope that is recognized by the monoclonal antibody, MO-1. The present study was undertaken to examine the effect of nerve injury in adult rats on these three developmentally regulated markers in two populations of somatic motor neurons. Unilateral transection, ligation, or crushing of the sciatic nerve resulted in a loss of MO-1 binding and a concomitant rise in immunoreactivity for NGFR within axotomized motor neurons in lumbar levels of the spinal cord. These changes, detectable within 5 days following nerve injury, are reversed with reinnervation, but persist if reinnervation is prevented by chronic axotomy. Thus, regulation of the expression of NGFR and the MO-1 epitope appears to be critically dependent upon interactions between motor neurons and target muscles. These observations are also consistent with the idea that during regeneration, neurons may revert to a developmentally immature state; in motor neurons, this state is characterized by the presence of NGFRs and the absence of the MO-1 epitope. Transection of the hypoglossal nerve, a purely motor nerve, resulted in a similar loss of MO-1 binding and a selective rise in NGFR immunoreactivity in neurons within the ipsilateral hypoglossal motor nucleus. In addition, immunoreactivity for ChAT was also lost in axotomized hypoglossal motor neurons. In contrast, injury to the sciatic nerve, which bears both sensory and motor axons, did not result in any detectable change in ChAT immunoreactivity in spinal motor neurons.     

Assembly of an abundant endogenous major histocompatibility complex class II/peptide complex in class II compartments

To identify the intracellular site(s) of formation of an endogenous class II/peptide complex in a human B cell line, we employed kinetic pulse-chase labeling experiments followed by subcellular fractionation by Percoll density gradient centrifugation and immunogold labeling on ultrathin cryosections. For direct demonstration of assembly of such complexes, we used the monoclonal antibody YAe, which detects an endogenous complex of the mouse class II molecule I-Ab with a 17-amino acid peptide derived from the alpha chain of HLA-DR (DR alpha52-68). We show that in human B lymphocytes, these class II/peptide complexes assemble and transiently accumulate in major histocompatibility complex class II-enriched compartments before reaching the cell surface.     

Effect of cervical carcinoma in situ and its management on pregnancy outcome

Small decreases in hydration status can result in a dramatic decrement in athletic performance and greatly increase the risk of thermal injury. Because of its osmotic properties, which enable greater fluid retention than the ingestion of water alone, glycerol has been proposed as a hyperhydrating agent. In fact, glycerol is now commercially available and marketed as a sport supplement to be ingested with water or sport drinks; thus, dietitians need to be cognizant of this new addition to the sports nutrition table. The results of glycerol-induced hyperhydration research have been equivocal, most likely because of methodologic differences between studies, such as variations in the intensity of exercise, environmental conditions, and concentration or dose of glycerol administered. Although the suggested dosage of glycerol depends on body size and varies between manufacturers, 1 g/kg body weight with an additional 1.5 L fluid taken 60 to 120 minutes before competition is standard. Some test subjects reported feeling bloated or nauseated after ingesting glycerol. This review examines glycerol-induced hyperhydration research and the safety of ingesting glycerol, discusses commercial availability of glycerol, and makes recommendations for glycerol-induced hyperhydration research.     

Establishing the etiology of childhood hearing loss

The cause of hearing loss in children is often difficult to identify. We evaluated a cohort of 114 children (47 boys, 67 girls) referred with newly diagnosed hearing loss (non-otitis media) to identify factors predictive of etiology and type of hearing loss. Clinical (history and physical examination), laboratory, and radiographic data were collected. One hundred children (87.7%) had sensorineural hearing loss, and 14 (12.3%) had conductive or mixed hearing loss. The cause of hearing loss was identified in 54 children (48%). Patients with isolated aural atresia (n = 7) or with a known diagnosis of congenital cytomegalovirus infection (n = 21) were excluded from further data analysis. We conducted statistical analysis to identify factors predictive of the cause and type of hearing loss. Clinical factors that aided in identifying a cause included abnormal physical examination findings (p = 0.001) and craniofacial anomalies (p = 0.006). Computed tomography of the temporal bones was the only diagnostic test predictive of cause (p < 0.001). Factors predictive of the type of hearing loss detected (sensorineural vs. conductive or mixed) were abnormal physical examination findings (p = 0.01) and craniofacial anomalies (p = 0.004). An exhaustive laboratory or radiographic workup did not prove beneficial in identifying the etiology of hearing loss in our series.     

Alcohol-membrane interaction: calcium uptake in mitochondria

A biphasic effect of ethanol was observed on Ca2+-uptake activity, Ca2+-uncoupled respiratory control ratio (CURCR), and State 3 oxygen uptake. At low concentrations (0.1-0.5%) ethanol enhanced these activities, probably as the result of an increase in membrane fluidity. At higher levels (0.7-4.0%) ethanol had an inhibitory influence on mitochondrial activities as the membrane macromolecules were probably disturbed due to the hydrophobic alcohol-membrane interaction.     

氧饱和煤焦和二氧化碳气化煤焦的TPD—MS谱分析

氧饱和煤焦的TPD-MS谱中的CO_2脱附曲线是宽阔带状,在683K附近有一个脱附峰,CO脱附曲线有一个由963K主峰和1083K的肩峰组成的巨大脱附峰及一个在1473K附近的脱附峰。CO_2气化煤焦的TPD—MS谱只有一条CO脱附曲线,在1253和1473K附近突出两个脱附峰。用CO处理的煤焦样品的TPD-MS谱与CO_2气化煤焦样品的TPD-MS谱相似。由此推测仅有两种分别具有半醌型和环醚型结构的碳表面氧化物参与气化反应,并从结构角度解释了煤焦CO_2气化反应的机理。     

Mammalian exocrine secretions XVI. Constitutents of secretion of supplementary sacculi of dwarf hamster, Phodopus sungorus sungorus

As a first step in a study of the role of the secretion of the supplementary sacculi (buccal secretion) of the dwarf hamster, Phodopus sungorus sungorus, almost complete chemical characterization of the secretion was achieved. The 35 compounds identified include carbon dioxide, hydrogen sulfide, a large number of carboxylic acids (representing the bulk of the organic volatile fraction of the secretion), phenol, 2-piperidone, indole, two long-chain hydroxyesters, cholestrol, desmosterol, and lanosterol. The position of the double bonds in -icosadienyl--butyrolactone and -henicosadienyl--butyrolactone could not be determined, and these two compounds remained only partially characterized. Large variations were found in the relative concentrations in which the short-chain carboxylic acids are present in the secretions of individual animals, and although this aspect was not investigated in sufficient detail in the present investigation, the difference in the carboxylic acid profiles of the secretions of individual animals could play a role in individual recognition in this animal.     

A trial to enhance the efficiency of Cyclosporin A in the treatment of Schistosoma mansoni infection by immunization of mice

Cyclosporin A (CsA) acts in two distinct modes against Schistosoma mansoni (S. mansoni) infection. It behaves in part as an antihelminthic and also as an immunomodulator. In this study, two methods were performed to increase the efficacy of the subcurative dose of CsA (30 mg/kg). These methods were, passive immunization where the drug was given simultaneously with rabbit antisera post infection and active immunization where the worm surface antigen was given prior to infection. The results showed that both methods led to enhancement of the curative effect of the CsA. However, the active immunization gave more significant reduction in liver worm and egg loads. Histopathological study showed small size and few number of hepatic granulomas in the passively immunized group while in the active group, there was just few and small collection of inflammatory cells. Moreover, the indirect fluorescent antibody test visualized damage to the worm tegument in both types of immunization. Thus, it could be concluded that active immunization increased the immunomodulatory effect of CsA in treatment of S. mansoni with less toxic effects by using a subcurative dose.