Stellate neurones innervating the rat heart express N, L and P/Q calcium channels

BACKGROUND: Distension of the saphenous vein before and after coronary artery bypass grafting results in damage to mechanisms that regulate vascular tone. We have investigated the relationship between the magnitude of distending pressure and the degree of structural, biochemical and functional damage to the vessel wall. METHODS: Vessel segments that had been distended to either 100 or 300 mmHg were set up in isolated organ baths and the function of the smooth muscle and endothelial cells examined. All segments examined were then fixed for assessment of structural damage by scanning electron microscopy and for immunocytochemical localisation of endothelial nitric oxide synthase. RESULTS: Segments of saphenous vein distended to 100 mmHg retained their responsiveness to KCl (90 mmol/l) and phenylephrine (10(-6) mol/l), but those pressurised to 300 mmHg had significantly reduced responses to both agents. There was also a significant reduction in response to the endothelium-dependent dilators, acetylcholine (10(-10)-10(-6) mol/l) and bradykinin (10(-10)-10(-6) mol/l) in those segments distended to 300 mmHg. Quantitative studies of structural endothelial damage showed a significant loss of endothelium at 300 mmHg distension pressure. Remaining endothelial cells retained strong positive staining for endothelial nitric oxide synthase. By electron microscopic examination, those vessels distended to 100 mmHg showed lifting and rounding of individual cells, whereas segments distended to 300 mmHg revealed major areas of denuded endothelium. CONCLUSIONS: Distension of saphenous veins to pressures equivalent to those in the systemic circulation result in structural and biochemical changes in the endothelium that are not paralleled by immediate functional vasomotor changes.     

Inhibition of murine hepatic cytochrome P450 activities by natural and synthetic phenolic compounds

1. The effect of the phenolic compounds protocatechuic acid, chlorogenic acid, tannic acid, gallates and silybin on ethoxyresorufin O-dealkylase (CYP1A1), methoxyresorufin O-dealkylase (CYP1A2) and pentoxy-O-dealkylase (CYP2B) was examined in mouse liver microsomes from induced animals. 2. All compounds tested could inhibit cytochrome P450-mediated enzyme activities, but to different extents. Tannic acid was the most potent inhibitor, especially toward EROD activity with an IC50=2.6 microM. Synthetic dodecyl gallate was also relatively selective toward this enzyme activity with an IC50=120 microM. 3. Protocatechuic acid, chlorogenic and silybin were more selective towards PROD and MROD activities. Their relative inhibitory potency for PROD activity was as follows: chlorogenic acid > protocatechuic acid > silybin > dodecyl gallate > propyl gallate. Protocatechuic acid was a more effective inhibitor of MROD activity than chlorogenic acid, and propyl gallate more effective than dodecyl gallate. Thus, no clear structure-activity or selectivity relationship was observed. 4. Analysis of the kinetics of inhibition revealed that the inhibition in most cases was non-competitive in nature.     

Clinical outcome of patients infected with hepatitis C virus infection on survival after primary liver transplantation under tacrolimus

In 1994, as a result of both programme evaluations which identified students' fears and apprehensions about their practical ability, and a review of the literature on skill acquisition, experiential skills teaching was resumed within the faculty. Having invested considerable finance into the reconstruction of a skills centre to teach skills, it is now imperative that its use be formally evaluated. Part of the evaluative process includes a review of the empirical literature on the acquisition of psychomotor skills in nursing. This paper summarizes this review.     

Fifteen years experience with finger arterial pressure monitoring: assessment of the technology

We review the Finapres technology, embodied in several TNO-prototypes and in the Ohmeda 2300 and 2300e Finapres NIBP. Finapres is an acronym for FINger Arterial PRESsure, the device delivers a continuous finger arterial pressure waveform. Many papers report on the accuracy of the device in comparison with intra-arterial or with noninvasive but intermittent blood pressure measurements. We compiled the results of 43 such papers and found systolic, diastolic and mean accuracies, in this order, ranging from -48 to 30 mmHg, from -20 to 18 mmHg, and from -13 to 25 mmHg. Weighted for the number of subjects included pooled accuracies were -0.8 (SD 11.9), -1.6 (8.3) and -1.6 (7.6) mmHg respectively. Subdividing the pooled group according to criteria such as reference blood pressure, place of application, and prototype or commercial device we found no significant differences in mean differences or SD. Measurement at the finger allows uninterrupted recordings of long duration. The transmission of the pressure pulse along the arm arteries, however, causes distortion of the pulse waveform and depression of the mean blood pressure level. These effects can be reduced by appropriate filtering, and upper arm 'return-to-flow' calibration to bring accuracy and precision within AAMI limits. For the assessment of beat-to-beat changes in blood pressure and assessment of blood pressure variability Finapres proved a reliable alternative for invasive measurements when mean and diastolic pressures are concerned. Differences in systolic pressure are larger and reach statistical significance but are not of clinical relevance. Finger arteries are affected by contraction and dilatation in relation to psychological and physical (heat, cold, blood loss, orthostasis) stress. Effects of these phenomena are reduced by the built-in Physiocal algorithm. However, full smooth muscle contraction should be avoided in the awake patient by comforting the patient, and covering the hand. Arterial state can be monitored by observing the behaviour of the Physiocal algorithm. We conclude that Finapres accuracy and precision usually suffice for reliable tracking of changes in blood pressure. Diagnostic accuracy may be achieved with future application of corrective measures.     

Double blind, randomised, placebo controlled study of oral vancomycin in prevention of necrotising enterocolitis in preterm, very low birthweight infants

AIMS: To evaluate the effectiveness of oral vancomycin in the prophylaxis of necrotising enterocolitis in preterm, very low birthweight infants. METHODS: A prospective, double blind, randomised, placebo controlled study in a tertiary referral centre of a university teaching hospital was conducted on 140 very low birthweight infants consecutively admitted to the neonatal unit. The babies were randomly allocated to receive oral vancomycin (15 mg/kg every 8 hours for 7 days) or an equivalent volume of placebo solution. Prophylaxis was started 24 hours before the start of oral feeds. All suspected cases of necrotising enterocolitis were investigated with a full sepsis screen and serial abdominal radiographs. Necrotising enterocolitis was diagnosed and staged according to modified Bell's criteria. RESULTS: Nine of 71 infants receiving oral vancomycin and 19 of 69 infants receiving the placebo solution developed necrotising enterocolitis (p = 0.035). Infants with necrotising enterocolitis were associated with a significant increase in mortality (p = 0.026) and longer duration of hospital stay (p = 0.002). CONCLUSIONS: Prophylactic oral vancomycin conferred protection against necrotising enterocolitis in preterm, very low birthweight infants and was associated with a 50% reduction in the incidence. However, widespread implementation of this preventive measure is not recommended, as it would only be effective in necrotising enterocolitis caused by Gram positive organisms and could increase the danger of the emergence of vancomycin resistant or dependent organisms. Its use should be restricted to a high prevalence nursery for a short and well defined period in a selected group of high risk patients.     

Effects of EGb 761 on nitric oxide and oxygen free radicals, myocardial damage and arrhythmia in ischemia-reperfusion injury in vivo

The cardioprotective effects of EGb 761 on the release of nitric oxide (NO), the concentration of serum thiobarbituric acid reaction substance (TBARS), the activity of creatine kinase (CK) and the incidence of ventricular arrhythmias were investigated in myocardial ischemia-reperfusion injury in vivo. Using sodium nitrite (NaNO2) as standard source of nitric oxide (NO), we compared the correlation coefficients of the three measuring methods used currently in the determination of NOFe2+(DETC)2 complex with that of the measuring method suggested in this study. The result showed that measuring the whole height of three splitting signals is the best linear correlation to the concentration of NO comparing with other methods in this system. Using this method, we observed the effects of EGb 761 on NOFe2+(DETC)2 complex in myocardial ischemia-reperfusion injury in vivo. The hearts of the Wistar rats were subjected to 30 min of ischemia and 10 min of reperfusion in vivo. Different doses of EGb 761 (25, 50, 100, 200 mg/kg i.p.), superoxide dismutase (SOD, 10(4) U/kg), l-arginine (50 mg/kg i.p.) and nitric oxide synthase (NOS) inhibitor NG-nitro-l-arginine (NNA, 50 mg/kg i.p.) were administered to the ischemia-reperfusion rats. EGb 761 under the dose of 100 mg/kg increased the signal intensity of NOFe2+(DETC)2 complex, while EGb 761 at 200 mg/kg showed an effect of decreasing the signal intensity of NOFe2+(DETC)2 complex. EGb 761 inhibited the formation of TBARS, the release of CK, and mitigated the incidence of ventricular arrhythmias in a dose dependent way. Both l-arginine and SOD increased the signal intensity of NOFe2+(DETC)2 complex and inhibited the formation of TBARS, the leakage of CK and the incidence of ventricular arrhythmia. NNA not only had no protective effects on myocardial injury, but also increased the incidence of reperfusion-induced arrhythmia. In conclusion, EGb 761 has cardiovascular protective effects by means of adjusting the level of NO and inhibiting oxygen free radicals induced lipid peroxidation in myocardial ischemia-reperfusion injury in vivo.     

Anatomical observation on the external nasal arteries

BACKGROUND: We report experience with patients presenting with a specific combination of symptoms: unilateral sciatica, unilateral sensibility loss in the dermatomes S1 to S5 (hemi-saddle) and subjective micturation problems secondary to ruptured lumbar disc. Because of its similarities with a cauda equina syndrome, this combination of symptoms was thought to be a unilateral cauda equina syndrome and it was called hemi-cauda equina syndrome. Consequently, it was treated as an emergency. METHODS: Ten patients were evaluated. They compromised 2.3% of all patients undergoing lumbar discectomy. RESULTS: Outcome is good with only 10% persisting minor neurologic deficit (sensibility loss in dermatomes S3 to S5). With the exception of urinary retention or incontinence, duration of symptoms and signs does not seem to influence outcome. Comparing signs, symptoms and radiographic findings with those of a cauda equina syndrome which were recently and thoroughly studied, they were found to be more severe in cases of cauda equina syndrome. Especially, the good outcome, (apparently unrelated to the duration of symptoms in cases of hemi-cauda equina syndrome) contrasted with the treatment results of cauda equina syndrome. CONCLUSIONS: We defined the hemi-cauda equina syndrome from ruptured disc as a combination of unilateral leg pain, unilateral sensibility loss in dermatomes S1 to S5 and sphincter paralysis (proven urinary retention or incontinence). Motor deficit is not necessarily present. Emergency surgery is warranted. Patients presenting with micturation complaints other than urinary retention or incontinence do not suffer from a hemi-cauda equina syndrome.     

Repeated trimipramine induces dopamine D2/D3 and alpha1-adrenergic up-regulation

Trimipramine (TRI), which shows a clinical antidepressant activity, is chemically related to imipramine but does not inhibit the reuptake of noradrenaline and 5-hydroxytryptamine, nor does it induce beta-adrenergic down-regulation. The mechanism of its antidepressant activity is still unknown. The aim of the present study was to find out whether TRI given repeatedly was able to induce adaptive changes in the dopaminergic and alpha1-adrenergic systems, demonstrated by us previously for various antidepressants. TRI was given to male Wistar rats and male Albino Swiss mice perorally twice daily for 14 days. In the acute experiment TRI (given i.p.) does not antagonize the reserpine hypothermia in mice and does not potentiate the 5-hydroxytryptophan head twitches in rats. TRI given repeatedly to rats increases the locomotor hyperactivity induced by d-amphetamine, quinpirole and (+)-7-hydroxy-dipropyloaminotetralin (dopamine D2 and D3 effects). The stereotypies induced by d-amphetamine or apomorphine are not potentiated by TRI. It increases the behaviour stimulation evoked by phenylephrine (given intraventricularly) in rats, evaluated in the open field test as well as the aggressiveness evoked by clonidine in mice, both these effects being mediated by an alpha1-adrenergic receptor. It may be concluded that, like other tricyclic antidepressants studied previously, TRI given repeatedly increases the responsiveness of brain dopamine D2 and D3 (locomotor activity but not stereotypy) as well as alpha1-adrenergic receptors to their agonists. A question arises whether the reuptake inhibition is of any importance to the adaptive changes induced by repeated antidepressants, suggested to be responsible for the antidepressant activity.     

High dynamic range temperature point sensor using greenfluorescence intensity ratio in erbium-doped silica fiber

We propose a sensor based on the temperature dependant behavior of the two lines of green emission of the erbium ion. The ratio of the intensities of these two lines presents a very low dependance on pump wavelength and pump power fluctuations. The sensitivity of the ratio is 0.013/°C between room temperature and 600°C. In addition, the measurement is self-calibrated