A novel sidestream ultrasonic flow sensor for multiple breath washout in children.

OBJECTIVE: Inert gas multiple breath washout (MBW) for measuring Lung Clearance Index using mass spectrometry and 4% sulfur hexafluoride (SF(6)) as the tracer gas has been shown to be sensitive for detecting early Cystic Fibrosis (CF) lung disease. However, mass spectrometry requires bulky equipment and is expensive to buy and maintain. A novel sidestream ultrasonic device may overcome this problem. The aims of this study were to assess the feasibility and clinical validity of measuring lung volume (functional residual capacity, FRC) and the LCI using the sidestream ultrasonic flow sensor in children and adolescents with CF in relation to spirometry and plain chest radiographs. PATIENTS AND METHODS: MBW using the sidestream ultrasonic device and conventional spirometry were performed in 26 patients with CF and 22 healthy controls. RESULTS: In the controls (4.7-17.7 years) LCI was similar to that reported using mass spectrometry (mean (SD) 6.7 (0.5)). LCI was elevated in 77% of the CF children (6.8-18.9 years), whereas spirometry was abnormal in only 38.5%, 61.5%, and 26.9% for FEV(1), MEF(25), and FEV(1)/FVC, respectively. This was more marked in children <10 years. LCI correlated with the Crispin-Norman score, whereas FEV(1) did not. CONCLUSIONS: Sidestream ultrasonic MBW is a valid and simple alternative to mass spectrometry for assessing ventilation homogeneity in children.

Reduction of oxidative tissue injury and endothelial dysfunction by graduated reperfusion after cardioplegic arrest in isolated rat hearts.

The aim of this study was to investigate whether or not a graduated resumption of the perfusion pressure after cardioplegic ischaemic arrest will reduce the impact of oxygen free radicals on myocardium and the cardiovasculature. Langendorff-perfused rat hearts were subjected to cardioplegia and subsequent 40 min of global ischaemia at 25 degrees C. Reperfusion was carried out either abruptly (AR) or gradually (i.e., perfusion pressure stepwise increased from 40 to 75 mmHg within 30 min -GR). GR resulted in a significant improvement of percentage recovery of left ventricular systolic pressure as compared to AR. A marked increase of thiobarbituric acid reactive substances (TBARS) was detected in the effluent during AR, accompanied by an impaired release of the endothelial vasodilator NO and diminished coronary flow rates compared to the baseline values. GR resulted in a significant reduction of TBARS in the effluent and promoted a better recovery of coronary flow as well as endothelial release of NO during the later phase of reperfusion. It is concluded that graduated reperfusion is beneficial in reducing free radical mediated peroxidative tissue injury and endothelial dysfunction upon reoxygenation.

Rapid determination of the membrane potential of mitochondria in small biopsy specimens of the liver.

In liver transplantation, graft viability is ideally to be determined before implantation. Integrity of mitochondria may be a prerequisite to a viable graft. A new method is presented, which allows for the determination of the membrane potential of mitochondria (MPM; mV) in state 4 respiration within 50 min in 40-mg specimens, employing rhodamine 123 as a probe. Normal control showed a MPM of 239.2 mV. Storage in saline at 37 degrees C yielded an impaired MPM of 153.5 mV within 3 h. The cold storage at 1 degree C could preserve MPM at quasi-normal after 3 h but reduced it significantly after 24 h to 222.2 mV in saline (p < 0.005 vs. control) and 231.0 mV in UW solution (p < 0.05 vs. control): the difference between the 24-hour values was significant (p < 0.05).

[Recovery of healthy and hypertrophied hearts after global ischemia and gradual reperfusion]. / Récupération des coeurs sains et hypertrophiés après ischémie globale et reperfusion graduée.

The influence of pressure controlled reperfusion on the postischemic outcome of normal and normotensive hypertrophied rat hearts should be investigated. To induce normotensive cardiac hypertrophy, male Wistar rats received injections of isoprenaline (5 mg/kg s.c. bid for three days). Hearts were excised and perfused in the Langendorff-technique at a perfusion pressure of 75 mmHg for 30 min. After cardioplegia and 40 min of global ischemia at 25 degrees C the hearts were reperfused for 45 min. Reperfusion pressure was built up either abruptly (75 mmHg immediately) or gradually (from 40 mmHg to 75 mmHg within 30 min). Postischemic recovery was significantly affected by the mode of reperfusion in normal hearts where pressure controlled (gradual) reperfusion is superior to the abrupt reperfusion mode. In hypertrophied hearts the postischemic outcome did not differ from normal hearts if abrupt reperfusion was used, but gradual reperfusion only led to a comparably small amelioration of postischemic status.

[Recovery of healthy and hypertrophic hearts after global ischemia and graduated reperfusion]. / Récupération des coeurs sains et hypertrophiés après ischémie globale et reperfusion graduée.

The influence of pressure controlled reperfusion on the postischemic outcome of normal and normotensive hypertrophied rat hearts should be investigated. To induce normotensive cardiac hypertrophy, male Wistar rats received injections of isoprenaline (5 mg/kg s.c. bid for three days). Hearts were excised and perfused according to the Langendorff-technique at a perfusion pressure of 75 mm Hg for 30 min. After cardioplegia and 40 min of global ischemia at 25 degrees C the hearts were reperfuse for 45 min. Reperfusion pressure was increased either abruptly (75 mm Hg immediately) or gradually (from 40 mm Hg to 75 mm Hg within 30 min). Post-ischemic recovery was significantly affected by the mode of reperfusion in normal hearts, in which pressure controlled (gradual) reperfusion was superior to the abrupt reperfusion mode. In hypertrophied hearts, the post-ischemic outcome did not differ from normal hearts when abrupt reperfusion was used, but gradual reperfusion only led to a comparably small improvement of the post-ischemic status.

Pressure-controlled reperfusion improves postischemic recovery of LV-hypertrophied rat hearts.

The influence of pressure-controlled postischemic reperfusion (Rp) on functional and metabolic parameters in hearts of sham-operated rats and hypertrophied hearts of rats with aortic constriction were studied. Hypertrophied hearts are considered to be more susceptible to ischemia. The hearts were perfused in the Langendorff-technique for thirty minutes at 35 degrees C with Krebs-Henseleit bicarbonate buffer at a perfusion pressure (PP) of 75 mmHg and for five minutes at 15 degrees C with St. Thomas' Hospital cardioplegic solution at a PP of 60 mmHg. After a period of global ischemia of forty minutes' duration at 15 degrees C, reperfusion was started either abruptly (aRp: PP 75 mmHg immediately) or gently (gRp: PP 75 mmHg within thirty minutes); it lasted for forty-five minutes. Intraventricular peak systolic pressure (ISP) was monitored and energy-rich compounds (ATP, ADP, AMP, CrP, free Cr) were analyzed. In normal hearts, metabolic recovery was not affected by the mode of reperfusion, but functional recovery (ISP) averaged 88% of the preischemic control value after gRp as compared with 73% after aRp. In hypertrophied hearts, gentle reperfusion ameliorated both metabolic and functional recovery. At forty-five minute recovery, CrP averaged 5.1 mumol/g ww after aRp and 6.6 mumol/g ww after gRp (p less than 0.01), and ISP amounted to 73% of the preischemic control after aRp and to 85% after gRp.

[Dye dilution test to determine leakage during regional perfusion in the treatment of malignant tumors of the extremities]. / Farbstoffverdünnung zu Leakage-Bestimmung während regionaler Perfusion bei der Behandlung von malignen Tumoren der Extremitäten.

During regional perfusion of the extremity in the dog, the dye Evans blue (T 1824) was used as an indicator to control leakage from the isolated region into the systemic circulation. The rate of elimination of the dye was 10% +/- 2% per hour. A simulated leakage from the perfused region into the systemic circulation was determined with a sensitivity of 1,67%.

[The effect of n-butanol on the metabolic status of some organs of rats and the circulation of rabbits]. / Die Wirkung von n-Butanol auf den Stoffwechselstatus einiger Organe der Ratte und den Kreislauf von Kaninchen

Rats received n-butanol i.m. in a dose of 0.1 g/kg body weight/die during 50 days. The metabolic status of some organs was examined and compared to that of rats which in control experiments had received 0.9% NaCl-colution in an equivalent volume (double blind experiments). The tissue levels of metabolites of the adenylic acid-creatine phosphate system, of glycogen, glucose and lactate exhibited no significant differences in both the groups. In the liver the tissue level of glycogen, free creatine and total creatine was significantly elevated in rats which had received n-butanol. In concious rabbits the effect of n-butanol on circulatory parameters was investigated in double blind experiments. n-butanol was without a significant effect in a dosage of 0.008 g/kg. A dosage of 0.033 g/kg and particularly of 0.1 g/kg resulted in a transitory decrease in the heart rate and the systolic and especially diastolic blood pressure.

[Changes in transplantation antigens of the dog due to cerebral ischemia and their demonstration using the cytotoxic test]. / Hirnischämisch bedingte Veränderungen der Transplantationsantigene des Hundes und ihr Nachweis im cytotoxischen Test

Experiments were performed on 19 mongrel dogs. Changes of transplantation antigens by anesthesia and by brain ischemia were identified in cytotoxic tests. Brain ischemia was responsible for the significant alterations in 5 antigens, anesthesia alone induced significant changes in 3 antigens.