Effect of temperature decrease on the microbial population and process performance of a mesophilic anaerobic bioreactor.

The effect of a temperature decrease from 33 degrees C to 12 degrees C was investigated for anaerobic digestion of crop residues. A laboratory-scale reactor (R0) was inoculated with mesophilic sludge and operated as continuously stirred fed-batch system at temperatures of 12 degrees C, 18 degrees C and 33 degrees C. Changes in the microbial populations of the sludge were followed by means of fluorescence in situ hybridization analysis. Methane was produced in R0 at all temperatures. Stable long-term operation at 18 degress C was achieved yielding 151 mlCH4 gVS(added(-1) at a rate of 108 mlCH4 l(R)(-1)d(-1) once the microbial populations of the sludge had adapted to this temperature. After operation at 18 degrees C, the contents of R0 was mixed and distributed into three smaller reactors, which were operated at 18 degrees C (R18), 25 degrees C (R25) and 37 degrees C (R37), respectively. Methane production rates for R37 and R25 were 366 and 310 mlCH4 l(R)(-1)d(-1), respectively, which were higher than the 215 mlCH4 l(R)(-1)d(-1) obtained in R0 when this was operated at 33 degrees C. Hydrolysis was found to decrease when temperature was decreased and especially below 25 degrees C. At temperatures below 16 degrees C, acidogenesis and methanogenesis were the rate-limiting steps. Adaptation of the mesophilic sludge to 18 degrees C was indicated by an increase in the ratio of Bacteria to total prokaryotes (sum of Archaea and Bacteria). This was thought to be caused by enrichment of Bacteria in the sludge, which appeared to be an important adaptation mechanism. During the adaptation, the Methanomicrobiales and Methanosarcinaceae populations increased relative to the total Archaea population whereas the Methanosaeta population decreased. The population changes were reflected by reactor performance.

Diagnosis of pulmonary embolism in hospitalised patients: retrospective survey of an institutional standard.

The aim of the present study was to assess the safety and implementation of a diagnostic strategy in hospitalised patients with suspected acute pulmonary embolism (PE). A diagnostic strategy was established and implemented in a general hospital. A retrospective cohort study, including 400 consecutive in-patients, was performed in order to assess the appropriateness of the diagnostic management and the incidence of symptomatic venous thromboembolic events (VTE) during follow-up. PE was confirmed in 116 (29%) patients. The incremental value of adding compression ultrasonography (CUS) to multidetector-row computed tomography (MDCT) for the diagnosis of PE was 8.6%. PE was appropriately excluded in 169 (42%) patients due to a normal lung scan (n = 34), a negative MDCT providing an alternative diagnosis (n = 94), and a negative MDCT and CUS (n = 41). During follow-up, VTE occurred in 3.5% patients. The almost unique cause of inappropriate management was the absence of further work-up after a MDCT-negative result for PE providing no alternative diagnosis (n = 115). Inappropriate management was associated with a nonsignificant increased risk of VTE (7.2%). A frontline diagnostic work-up based on pulmonary multidetector-row computed tomography associated with a compression ultrasonography of the leg veins is effective and more sensitive than pulmonary multidetector-row computed tomography alone in ruling out pulmonary embolism.

Transient inactivation of the rat nucleus accumbens does not impair guidance of instrumental behaviour by stimuli predicting reward magnitude.

The involvement of the nucleus accumbens (NAc) in the determination of reaction times (RTs) of instrumental responses by the expectancy of future reward was investigated. A simple RT task demanding conditioned lever release was used, in which the upcoming reward magnitude (5 versus 1 pellet) was signalled in advance by discriminative cues. In rats which acquired the task, RTs of instrumental responses were significantly shorter to the discriminative cue predictive of high reward magnitude. Inactivation of the NAc by lidocaine had no effect on RTs and their determination by cue-associated reward magnitudes, and did not affect the rate of correct responses. In keeping with an earlier study, intra-NAc infusion of amphetamine decreased RTs, impaired RT determination by cue-associated reward magnitudes and reduced the rate of correct responses. The unexpected finding that lidocaine inactivation of the NAc had no effect parallels previous data showing that lesions of NAc did not impair RT performance, while manipulation of intra-NAc glutamate or dopamine transmission impaired various aspects of RT performance in comparable tasks. It is suggested that experimental manipulations such as transient and permanent inactivation, which almost completely inhibit NAc neuronal output, allow alternative routes to be used to effectively control behaviour in the task employed here.

NMDA and dopamine D2 receptors in the caudate-putamen are not involved in control of motor readiness in rats.

RATIONALE: In reaction time (RT) paradigms, in which a variable preparation interval preceded the imperative stimulus, RT become shorter as a function of increasing time from the start of a trial until presentation of the imperative stimulus. The shortening of RT as the preparatory foreperiod elapses reflects increasing motor readiness; however, the underlying neurochemical mechanisms are still poorly defined. OBJECTIVE: The present study investigated in rats whether signals transmitted via the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors and via dopamine D2 receptors in the caudate-putamen (CPu) are involved in motor readiness. METHODS: A simple RT task demanding conditioned lever release was used, in which the upcoming reward magnitude (5 pellets or 1 pellet) was signalled in advance by discriminative stimuli and the imperative stimulus was subsequently presented after a variable foreperiod (200, 500 or 800 ms). RESULTS: In intact rats, RT of conditioned responses was shortened with foreperiod lengthening and with expectancy of the high reward magnitude, but there was no interaction between both factors. Bilateral infusion of the competitive NMDA antagonist DL-2-amino-5-phosphonovaleric acid (APV) (2, 10 micrograms in 0.5 microliter/side), of the preferential dopamine D2 antagonist haloperidol (5, 12.5 micrograms in 0.5 microliter/side) or infusion of vehicle (0.5 microliter/side) into the central subregion of the CPu had no effect on progressive RT shortening with increasing foreperiod. CONCLUSION: The present data provide no clues to suggest that motor readiness relies on stimulation of dopamine D2 and NMDA receptors in the central CPu.

NMDA, but not dopamine D(2), receptors in the rat nucleus accumbens areinvolved in guidance of instrumental behavior by stimuli predicting reward magnitude.

Expectancy of future reward is an important factor guiding the speed of instrumental behavior. The present study sought to explore whether signals transmitted via the NMDA subtype of glutamate receptors and via dopamine D(2) receptors in the nucleus accumbens (NAc) are critical for the determination of reaction times (RTs) of instrumental responses by the expectancy of future reward. A simple RT task for rats demanding conditioned lever release was used in which the upcoming reward magnitude (5 or 1 pellet) was signaled in advance by discriminative stimuli. In trained rats, RTs of conditioned responses with expectancy of a high reward magnitude were found to be significantly shorter. The shortening of RTs by stimuli predictive of high reward to be obtained was dose-dependently impaired by bilateral intra-NAc infusion of the competitive NMDA antagonist dl-2-amino-5-phosphonovaleric acid (APV) (1, 2, or 10 microg in 0.5 microl/side), but not by infusion of the preferential dopamine D(2) antagonist haloperidol (5 and 12.5 microg in 0.5 microl/side) or by infusion of vehicle (0.5 microl/side). In conclusion, the data reveal that in well trained animals stimulation of intra-NAc NMDA, but not of dopamine D(2), receptors, is critically involved in guiding the speed of instrumental responses according to stimuli predictive of the upcoming reward magnitude.

[Simultaneous determination of inorganic anions in body fluids. A new method in pediatric laboratory diagnosis--results of a pilot study]. / Simultane Bestimmung anorganischer Anionen in Körperflüssigkeiten. Eine neue Methode in der pädiatrischen Labordiagnostik--Ergebnisse einer Pilotstudie.

The anions analysis was a methodical problem up to now. This was the reason for low interest. Biological fluids like saliva and urine which could easily receive without any stress for the children, are little investigated for its capacity on nitrite, nitrate, bromide and sulfate. In this performance there will presented an ion-chromatographic method to determine inorganic anions in the following body-fluids: serum saliva, liquor and urine. The anions chloride, nitrite, bromide, nitrate, phosphate and sulfate was determined quantitatively. The method was proved in a pilot-study on children's body-fluids serum, liquor and saliva. The objects was to get a landmark in expectation from anion concentrations. Bromide was detected as a constant part in all body fluids. The origin and importance is not clear till now. Also was found nitrate in all investigated body fluids. There seems to be a connection between diarrhea and an increase in serum levels from nitrate. We found considerable amounts of nitrate in saliva by babies and infants. The method is distinguished by little fluctuation in measurement and high specificity. Short time in analysis and simple handling will do the method for a qualified one in pediatrics.

[Exposure of our children to pesticides, PCB and potentially critical anions]. / Belastung unserer Kinder mit Pestiziden, PCB und potentiell kritischen Anionen.

Among environmental pollutants the organohalogens still play an important role since they accumulate in human fat tissue and are secreted with mother's milk during lactation. Fortunately DDT-, HCH- and HCB-levels decreased in breast milk during the last years. In contrast, the PCB concentrations were still three-to five-fold above the permitted limits for cow's milk. Fat tissue of 262 newborns, infants and children was already as severely loaded with organohalogens as human milk. However, children with malignant tumors or congenital malformations did not show elevated concentrations in fat tissue. The significance of the potentially critical anions such as nitrate, nitrite, bromide, sulfate for the health of our children needs further clarification.

Reversal of left ventricular hypertrophy and improvement of cardiac function in man by nifedipine.

The effects of long-term (mean 3.9 months) pharmacotherapy of hypertensive and normotensive hypertrophy (hypertensive heart disease, hypertrophic non-obstructive cardiomyopathy) as well as of advanced cardiac disease due to coronary artery disease and dilatative cardiomyopathy by large doses of nifedipine (mean 120 mg/day-1) were analyzed with regard to systolic blood pressure, to left ventricular function and to the hypertrophy degree of the ventricle. Nifedipine, in addition to conventional and maintained antihypertensive and cardiac therapy, lowers blood pressure in hypertensive patients, whereas hypotensive effects in the normotensive patients were absent. Nifedipine enhances left ventricular function in all patient groups significantly, i.e. in normotensive hypertrophic non-obstructive cardiomyopathy, in hypertensive heart disease and especially in heart disease due to coronary artery disease and dilatative cardiomyopathy. Significant regression of septal and of global hypertrophy was found in hypertrophic non-obstructive cardiomyopathy and in hypertensive heart disease. These results indicate, that long-term nifedipine treatment may be beneficial for left ventricular function in all patient groups and for hypertrophy regression in established left ventricular hypertrophy due to hypertrophic, non-obstructive cardiomyopathy and due to hypertensive left ventricular hypertrophy. It is concluded that long-term nifedipine treatment improves left ventricular function and leads to regression of established ventricular wall hypertrophy in hypertrophic non-obstructive cardiomyopathy and in hypertensive heart disease.

Contractile, coronary, and metabolic effects of the acute and long-term treatment of cardiac failure with prenalterol.

Prenalterol was examined with regard to its acute intravenous effects on left ventricular function, coronary hemodynamics, and myocardial oxygen consumption, as well as for its long-term effects, by oral therapy, on left ventricular function and systemic hemodynamics. Intravenous prenalterol enhances myocardial contractility and left ventricular ejection function significantly. A decrease in total peripheral vascular resistance is effected. Myocardial oxygen consumption is only moderately increased, most probably because of the decrease in the systolic integrated wall stress of the left ventricle. The changes of coronary circulation (blood flow, resistance, arteriovenous, oxygen difference) indicate benign and metabolically induced coronary vasodilation. Long-term oral treatment of patients with severe cardiac failure by prenalterol effects significant enhancement in-left ventricular performance within the first 1-2 months of treatment; however, this effect is not present at longer therapy intervals (16-28 weeks). Tolerance development as well as the natural history of these patients may be responsible for this inotropic amelioration. There were no clinical side effects with either intravenous or oral application. It may be concluded that prenalterol is highly effective in acute cardiac failure (intravenous administration) and also in chronic heart disease (long-term oral application). However, the long-term effects are unpredictable, and tolerance development has to be considered.

Global and regional wall motion and contractility of the left ventricle following cigarette smoking.

The hemodynamic and contractile effects of acute cigarette smoking were analyzed in 35 patients with normal cardiac and coronary function as well as with cardiac failure and with coronary artery disease. In normal patients (normal ventricular function, normal coronary arteriogram) cigarette smoking exhibited no contractile depressant effects. Moderate increase in global and in regional wall motion and contractility was found. Likewise, in patients with compensated hypertensive hypertrophy (normal ventriculogram, significant left ventricular hypertrophy, normal coronary arteriogram) cigarette smoking increased global and regional contraction function. In cardiac disease patients (dilatative cardiomyopathy, advanced coronary artery disease, decompensated hypertensive heart disease) cigarette smoking was associated with depression in the overall and regional contraction behavior of the left ventricular myocardium. In patients with coronary artery disease, cigarette smoking was accompanied by marked depression of the regional contraction pattern in hypokinetic, akinetic, and dyskinetic zones. Moreover, contractile depression also occurred in the non-ischemic zones, without pre-existing coronary artery stenoses. In conclusion, acute cigarette smoking may not cause contractile depressant effects in normal patients and patients with compensated hypertensive hypertrophy. However, in coronary patients, significant negative inotropic effects are present not only in the ischemic zones, but also in the non-ischemic myocardium.

Influence of background and absorption correction on nuclear quantification of left ventricular end-diastolic volume.

Left ventricular (LV) end-diastolic volume (EDV) was determined in millilitres by equilibrium radionuclide ventriculography (MUGA) in 38 patients and in 15 normal individuals by applying corrections for background (BC), LV blood self-absorption and for absorption by the thoracic and LV walls. Volume calibration was performed by measuring a syringe containing the patient's venous blood with the gamma camera. Single plane cineventriculography (CVG) served as the reference method. Without absorption correction, LV volume values were underestimated by a factor of 3.6 on the average. Several background models (uniform, parabolic, no background) were investigated. Without BC, EDV was overestimated, and with uniform BC, EDV was underestimated. EDV calculated using a parabolic BC with a correction for absorption yielded the best correlation (r = 0.96) with volumes (VOL) obtained by CVG (VOLMUGA [ml] = -6.83 + 1.060 X VOLCVG).

[Functional evaluation of left ventricular dynamics by use of 2-dimensional echocardiography: comparison with left ventriculography and assessment of normal 2-dimensional echocardiographical values]. / Funktionsbeurteilung des Herzens mittels zweidimensionaler Echokardiographie: Vergleichende Untersuchungen zur Cineangiographie und Erstellung von Normalwerten für Erwachsene.

The role of 2-dimensional echocardiography was comparatively evaluated to left ventriculography, with special reference to determinations of left ventricular volume (enddiastolic volume, endsystolic volume), ejection fraction, systolic and diastolic wall stress and left ventricular muscle mass. Prior to left ventriculography, 25 consecutive patients were examined by 2-dimensional echocardiography. There were significant correlations (2-dimensional echocardiography, left ventriculography) between left ventricular volumes, ejection fractions and left ventricular muscle mass. No sufficient correlation was found for systolic wall stress, mainly because of the different wall thickness calculations. Good correlation for systolic wall stress was found when left ventricular dimensions (enddiastolic volume, enddiastolic radius), systolic pressure and M-Mode wall thickness (Ratshin technique) was employed. Methodological combination of measurements of wall thickness by M-Mode echocardiography and measurement of ventricular dimensions by 2-dimensional echocardiography represents a useful advantage in the evaluation of systolic wall stress and left ventricular muscle mass. On the basis of these analyses, 22 healthy volunteers were examined and normal values were established.