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Notes: Abstract: Metabolism of [U-13C5]glutamine was studied in primary cultures of cerebral cortical astrocytes in the presence or absence of extracellular glutamate. Perchloric acid extracts of the cells as well as redissolved lyophilized media were subjected to nuclear magnetic resonance and mass spectrometry to identify 13C-labeled metabolites. Label from glutamine was found in glutamate and to a lesser extent in lactate and alanine. In the presence of unlabeled glutamate, label was also observed in aspartate. It could be clearly demonstrated that some [U-13C5]glutamine is metabolized through the tricarboxylic acid cycle, although to a much smaller extent than previously shown for [U-13C5]glutamate. Lactate formation from tricarboxylic acid cycle intermediates has previously been demonstrated. It has, however, not been demonstrated that pyruvate, formed from glutamate or glutamine, may reenter the tricarboxylic acid cycle after conversion to acetyl-CoA. The present work demonstrates that this pathway is active, because [4,5-13C2]glutamate was observed in astrocytes incubated with [U-13C5]glutamine in the additional presence of unlabeled glutamate. Furthermore, using mass spectrometry, mono-labeled alanine, glutamate, and glutamine were detected. This isotopomer could be derived via the action of pyruvate carboxylase using 13CO2 produced within the mitochondria or from labeled intermediates that had stayed in the tricarboxylic acid cycle for more than one turn.

Notes: Motoneuron dependence on target-derived trophic factors during development is well established, with loss of trophic support leading to the death of these cells. A complete understanding of the intracellular signal transduction machinery associated with extracellular survival signals requires the examination of individual pathways in various cellular and environmental contexts. In cells deprived of trophic support, and hence compromised for survival, phosphoinositide-3-kinase (PI3K) is decreased when compared with healthy cells supplied with trophic support. Extracellular signal-regulated kinase 1/2 (ERK1/2) signaling is dramatically decreased in deprived cells. We have examined the role of these two pathways to understand how changes in their activity regulate motoneuron survival and death. Pharmacological inhibition of PI3K attenuated motoneuron survival and was important in the regulation of Bcl-2 serine phosphorylation, limited release of cytochrome c into the cytoplasm and caspase activation. Bax translocation from cytoplasm to mitochondria was not altered when PI3K was inhibited. High levels of ERK1/2 inhibition robustly attenuated motoneuron survival in cells supplied with trophic support, whereas moderate inhibition of ERK1/2 activation had little effect. ERK1/2 inhibition in these cells decreased Bcl-2 phosphorylation and resulted in release of cytochrome c from the mitochondria. Bax translocation and caspase activation were not affected by ERK1/2 inhibition. These data reveal that changes in PI3K and ERK1/2 signaling lead to individual and overlapping effects on the cell-death machinery. Characterizing the role of these pathways is critical for a fundamental understanding of the development and degeneration of specific neuronal populations.

Notes: Objective  To assess whether outpatient hysteroscopy using the ‘no-touch’ technique confers any advantages in terms of patient discomfort over the traditional technique.Design  Prospective randomised controlled study.Setting  Outpatient hysteroscopy clinic in a large university undergraduate teaching hospital.Population  All women referred for outpatient hysteroscopy in a 12-month period.Interventions  Women were randomised to undergo either traditional saline hysteroscopy requiring the use of a speculum and tenaculum, or a ‘no-touch’ vaginoscopic hysteroscopy which does not require a speculum or tenaculum. Each group was further subdivided to have hysteroscopy with either a 2.9-mm or 4-mm hysteroscope. Patients were asked to complete pre- and postprocedure questionnaires ranking pain scores.Main outcome measures  The relative success of each of these techniques, requirement for local anaesthetic and pain scores at different times during the hysteroscopy were recorded at the end of the procedure. The time taken to carry out each procedure was also measured.Results  One hundred and twenty women were recruited in this study: 60 were randomised to traditional hysteroscopy and 60 to ‘no-touch’ hysteroscopy. The overall success rate for hysteroscopy was 99%. There was no significant difference in the requirement for local anaesthetic between the two groups, but those who underwent ‘no-touch’ hysteroscopy with a 2.9-mm hysteroscope had the lowest requirement of local anaesthetic (10% compared with 27% in the no-touch hysteroscopy with a 4-mm hysteroscope group). The time taken to perform hysteroscopy and biopsy was significantly shorter with ‘no-touch’ hysteroscopy (5.9 vs 7.8 min; difference 1.9, 95% CI 0.7–3.1). There were no differences in pain scores between the groups at different times during hysteroscopy.Conclusions  ‘No-touch’ or vaginoscopic hysteroscopy is significantly faster to perform than the traditional technique. Although there was no difference in pain scores between the two techniques, local anaesthetic requirements were least in those who underwent ‘no-touch’ hysteroscopy with a narrow bore hysteroscope.

Notes: Objectives  To evaluate triple tourniquets in controlled conditions and for the first time to investigate the hypothesis that leaving a semi-permanent tourniquet around the uterine artery reduces post-operative bleeding from the uterine incisions.Design  A randomised controlled trial.Setting  Two University teaching hospitals.Population  Twenty-eight patients with symptomatic fibroids and uterine sizes ranging from 14 to 24 weeks of gestation undergoing open myomectomy.Methods  A number 1 polyglactin suture was tied around the cervix to occlude the uterine arteries, and polythene tourniquets were tied around the infundibulopelvic ligament to obstruct the ovarian vessels. At the end of the procedure, the ovarian ties were released but the uterine artery suture remained in situ.Main outcome measures  Intra-operative blood loss, post-operative blood loss, blood transfusion rates, operative morbidity, uterine blood flow and ovarian function.Results  There was significantly less blood lost in the tourniquet group than in the control group (difference between means 1870 mL, 95% CI 1159–2580 mL, P 〈 0.0001; transfusion rates of 7% and 79%, P= 0.0003). The volume in the pelvic drain 20 min post-operatively and after 48 hours failed to reach statistical significance between the two groups (P= 0.10 and P= 0.165). There were no differences in uterine artery Doppler resistance indices at five days (P= 0.54), six weeks (P= 0.47), three months (P= 0.49) and at six months (P= 0.18). Day two serum FSH concentrations after surgery were unchanged (P= 0.45), compared with baseline values.Conclusions  Triple tourniquets are effective in reducing bleeding and transfusion rates. There appears no obvious adverse effect on uterine perfusion or ovarian function.

Notes: Suspensions (20%) of microfine and ACS grade zinc oxide, or 20% titanium oxide in water, castor oil or polyethylene glycol were applied topically to rabbit skin over 4 h (1 day) or 2 h daily (3 days). Skin sites were analysed for metal uptake. Percutaneous absorption of the oxides was probably low, most remaining on the skin surface. Uptake patterns were influenced by the vehicles used. Appreciably more microfine zinc oxide was taken up by the skin in subacute studies. Local changes in trace metal concentration were construed as evidence of percutaneous absorption of zinc and titanium oxides. Further studies are indicated to validate the significance of these preliminary observations. On a applique superficiellement a de la peau de lapin des suspensions a 20% d'oxyde de zinc de qualite microfine ou ACS, ou a 20% d'oxyde de titane dans l'eau, l'huile de castor ou le polyethylene glycol, durant 4 heures (1 jour) ou 2 heures par jour (3 jours). On a analyse l'absorption de metal par la peau. L'absorption transcutanee des oxydes est probablement faible, la majeure partie restant en surface. Le deroulement de l'absorption est influence par le vecteur utilise. On constate que notablement plus d'oxyde de zinc microfin est absorbe par la peau dans les etudes subaigues. Les modifications locales dans la concentration des traces de metal ont ete interpretees comme des preuves d'absorption transcutanee d'oxydes de zinc et de titane. Des etudes ulterieures sont necessaires pour valider la signification de ces observations preliminaires.

Notes: We describe the generation of terahertz radiation by optical rectification in an electro-optic crystal mosaic. The mosaic is constructed from four single crystals of the organic salt dimethyl amino 4-N-methylstilbazolium tosylate and is approximately 1 cm2 in area. We characterize both the optical rectification efficiency and the spatial and temporal profiles of the generated terahertz beam, and find that the mosaic performs as well as a single crystal. © 1995 American Institute of Physics.

Notes: We report on the scalability of generating terahertz radiation by optical rectification with the electro-optic materials LiNbO3, LiTaO3, and dimethyl amino 4-N-methylstilbazolium tosylate (DAST). A Ti:sapphire laser system, producing 215 fs, 20 mJ pulses at 810 nm, was used for the experiment. Using LiNbO3 and LiTaO3, the peak of the generated terahertz electric field was found to scale linearly with increasing optical fluence for fluences up to 60 mJ/cm2, while with DAST the peak field scaled sublinearly in this fluence range. © 1995 American Institute of Physics.

Notes: Stereotactic methods have been successfully used for the treatment of a wide range of neurological disorders. The main difficulties experienced with the current systems are their cumbersome frames and their time consuming positioning procedures. The South African Medical Research Council/University of Cape Town Biostereometrics Group, together with the Department of Neurosurgery of the University of Cape Town, in an attempt to overcome the problems associated with the present stereotactic guidance frames, have developed a very simple probe pointing device. The Cape Town Stereotactic Pointer (CTSP) is based on stereophotogrammetric principles but uses computed tomography as the imaging and measuring medium.

Notes: This study was designed to assess the incidence, severity and possible aetiological factors ofpostanaesthetic shivering in children. Three hundred and seventy-six children undergoing general anaesthesia were enrolled in the study. Tympanic membrane temperatures were recorded pre-operatively and every 15 min postoperatively in the recovery room until discharge to the ward. Also recorded were all anaesthetic data including fluid administration, methods of temperature preservation used, sedation scores and shivering (using a four-point scale). The overall incidence of shivering was 14.4%. Multiple regression analysis identified three factors that were significantly related to shivering: age, the administration of atropine and peri-operative temperature changes. Children who shivered rewarmed faster in the recovery room.