Crosslinking of tRNA containing a long extra arm to elongation factor Tu by trans-diamminedichloroplatinum(II).

A tRNA containing a long extra arm, namely E. coli tRNA(Leu1) has been crosslinked to elongation factor Tu, with the crosslinking reagent trans-diamminedichloroplatinum(II). The nucleotide involved in the crosslinking was identified to be a guanosine in the variable region at position 47F or 47G.

Acid-base interactions with noradrenaline-induced contractile response of the rabbit isolated aorta.

The effect of acidosis and alkalosis on vascular smooth muscle contractions evoked by noradrenaline was studied. Helical strips of rabbit aorta were mounted for isometric tension recording. Acidosis (pH 7.24-6.51) was obtained by either increasing the PCO2 (hypercapnic) and/or lowering the HCO3-concentration (hypobicarbonatic). Acidosis shifted the noradrenaline concentration-response curve to the right in a competitive manner. The maximal developed tension was unchanged at pH 7.24-6.90 and decreased by 30% at pH 6.51. Alkalosis (pH 7.61-8.04) did not alter noradrenaline-evoked contractions. The results suggest that hydrogen ions during acidosis (pH less than 7.40) but not during alkalosis (pH greater than 7.40) exert alpha-adrenoceptor blocking properties.

Production of leucocyte poor blood. A comparison of five different methods.

The efficiency of leucocyte removal and the degree of erythrocyte loss were investigated by five different methods. The methods were: 1) saline washing of red blood cells (RBC) in the cell separator, 2) centrifugation of whole blood in glass bottles followed by removal of plasma and buffy coat by suction. 3) Imugard-Terumo filtration of whole blood, 4) inverse centrifugation of blood in a double plastic bag followed by transferring the RBC to the satellite bag, and 5) sedimentation of RBCs in CPD-dextran followed by dripping the RBCs to another glass bottle. Method no. 5 was clearly the most efficient, containing a mean of 20.8% of the offered leucocytes. After washing in saline three times this could be lowered to 7.0%. Method no. 3 was the second best method, having the lowest degree of erythrocyte loss. Methods no. 2 and 4 are approximately of the same quality. However method no. 1 was bad and can not be recommended for production of leucocyte poor blood in the present modification.

Arterial carbon dioxide tensions during anaesthesia with manual ventilation. A descriptive study of the effects of various non-polluting circuits.

In 660 supine, intubated and anaesthetized, healthy patients scheduled for various elective surgical procedures, the distribution of arterial carbon dioxide tension (PaCO2) was investigated during manual non-monitored ventilation. The study comprised six equal groups: group 1: ventilation with a circle circuit absorber system; group 2: ventilation with the Hafnia A circuit using a total fresh gas flow (FGF) of 100 ml . kg-1 . min-1; groups 3-6: ventilation with a Hafnia D circuit with fresh gas flows of 100, 80, 70 and 60 ml . kg-1 . min-1, respectively. The mean PaCO2's of the first three groups were situated in the lower range of normocapnia (the observations in the first group having the greatest total range), whereas the rebreathing (Hafnia A and D) circuits resulted in a clustering of observed data. Employing the rebreathing circuits, protection against hypocapnia can be achieved by lowering the fresh gas flow. The most satisfying result was obtained with the Hafnia D circuit with a fresh gas flow of 70 ml . kg-1 . min-1 resulting in normocapnia with a modest and limited spread towards hypo- and hypercapnia. FGF in excess of this level must be considered as wasted. The study indicates that corrections of fresh gas flows for age are superfluous. Use of relaxants and type of surgery had no influence on the observations.

Method for continuous measurement of carbon dioxide output during anesthesia. An assessment.

Employing the Mapleson D circuit, a modified closed-circuit flow-through technique for the continuous measurement of carbon dioxide production (VCO2) was tested for accuracy and precision in a lung model. The recovery of carbon dioxide production was found to be between 90 and 110%, the maximized errors for a single estimate of carbon dioxide production were between +/- 4 and +/- 28%, with the highest errors at high gas flows and low carbon dioxide inputs. Accepting arbitrarily chosen limits of maximized errors of +/- 10%, it could be shown that the system did not work acceptably when the mean carbon dioxide concentration was below 1.5 vol.% within the fresh gas flow rates (2.2--7.7 1 min-1) and the range of minute ventilation (4--10 1 min-1) employed. The half-life of carbon dioxide washout varied between 41 and 138 s, thus limiting the suitability of the system for detecting changes in carbon dioxide output. The method may be used as an approximate monitor of VCO2 in anaesthetized patients, but cannot be regarded as sufficient for research purposes.

[A new safe system for the prevention of peroperative hypothermia (author's transl)]. / Ein neues, sicheres System zur Verhinderung peroperativer Hypothermie.

On the basis of our experiences and data from the literature concerning thermal injury by warming blankets in anaesthetized patients, a new and safe system for the maintenance of body temperature during the operation is described. The following advantages are emphasized: 1. Adjustable double-thermostat with audible alarm. 2. Easy-to-read control thermometer of water bath. 3. Thermal blanket water temperature cannot rise above 43 degrees C.

Althesin in neurosurgical patients: effects on cerebral hemodynamics and metabolism.

The effect of althesin 0.5 ml/10 kg on arterial blood pressure, intracranial pressure, cerebral blood flow and oxygen uptake was studied on 19 occasions in 16 patients with varied cerebral pathology. Cerebral blood flow (CBF) was measured using the intracarotid 133xenon method and a 35-channel scintillation detector after cannulation of the internal carotid artery, the internal jugular bulb and the lateral cerebral ventricle. Arterial and intracranial pressures were recorded continuously. Blood gas tensions were measured in simultaneously drawn samples from the internal carotid artery and the jugular bulb. Cerebral oxygen uptake was calculated from the product of CBF and arteriovenous oxygen content difference. Control values were obtained with the patients under a basic general anesthesia, consisting of N2O/O2 pancuronium. The effect of a bolus injection of althesin was then studied 1 and 20 min after the injection. A significant reduction in intracranial pressure, cerebral blood flow and metabolism at 1 min was found to have essentially subsided 20 min after the injection. In patients with focal brain damage, regional flow analysis revealed a paradoxical increase in flow after althesin in the areas corresponding to the focus.