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Biomedical subjects

J Heinonen

Publications and source records attributed to J Heinonen.

At least 73 records · Page 4Linked to original sources
PubMed1982

Oxygen delivery during endobronchial anaesthesia: a comparison of halothane-oxygen and nitrous oxide-oxygen.

Total oxygen delivery (cardiac output X arterial oxygen content) and oxygen consumption were determined in 22 patients undergoing one-lung ventilation (OLV) during thoracotomy. In 11 patients, anaesthesia was maintained with halothane-oxygen and in another 11 patients with nitrous oxide-oxygen-analgesic combination (FIO2 0.5). During OLV, oxygen delivery was greater in the halothane group and these patients tended to show a decrease in oxygen consumption compared with the patients of the nitrous oxide group. Therefore, as far as total oxygen balance (oxygen delivery/oxygen consumption) during OLV is concerned, halothane-oxygen maintenance provides a greater margin of safety than nitrous oxide-oxygen-analgesic combination. However, in spite of occasional hypoxaemic episodes, none of our patients receiving 50% nitrous oxide in oxygen showed an oxygen delivery coefficient (oxygen delivery/oxygen consumption) significantly smaller than the predicted normal value for an unanaesthetized patient. This finding may explain why this anaesthetic technique has been used without apparent harm during OLV in patients with unimpaired cardiovascular function.

Anesthesia↗
PubMed1982

Attenuation of circulatory response to laryngoscopy and tracheal intubation: a comparison of two methods of topical anaesthesia.

Circulatory responses to laryngoscopy and endotracheal intubation were compared between three groups of patients, two of which were subjected to a procedure of topical anaesthesia before induction of general anaesthesia. Topical anaesthesia, achieved with either a lidocaine dose aerosol or by gargling with viscous lidocaine, attenuated the magnitude of the pressor response to laryngoscopy and intubation but had no effect on the heart rate response. Lidocaine aerosol had some advantages over viscous lidocaine; these were the significantly smaller haemodynamic response to the local anaesthetic procedure itself and probably shorter duration of the circulatory changes produced by intubation. It is concluded that both of these simple methods are relatively ineffective in preventing haemodynamic changes associated with laryngoscopy and intubation and should probably be combined with another preventive method.

Adult↗
PubMed1982

The intracellular concentration of pyrophosphate in the batch culture of Escherichia coli.

We applied our colorimetric PPi determination method [Heinonen, J., Honkasalo, S. and Kukko, E. (1981) Anal. Biochem. 117, 293-300] to bacterial cultures and measured the intracellular concentration of PPi in the batch culture of Escherichia coli. The cells growing in minimal medium contained about 2.5 nmol PPi/mg protein (0.5 mM). There was no extracellular PPi. A similar concentration of PPi was found also in cells growing in minimal medium enriched by amino acid mixture.

Colorimetry↗
PubMed1981

Activity changes of inorganic pyrophosphatase of Streptococcus faecalis during batch culture.

The state of inorganic pyrophosphatase (EC 3.6.1.1) from Streptococcus faecalis ATCC 8043 was studied in different phases of batch culture. The degree of inactivation (i.e. the ratio of activities observed before and after incubation at 37 degrees C without cysteine) was highest, and the degree of activation (i.e. the ratio of activities after and before incubation in the presence of cysteine) was lowest, in samples taken during the early-exponential growth phase. During the various phases of batch culture, the specific activity before incubation and the degree of inactivation changed in parallel, whereas the specific activity observed after incubation remained nearly constant. During the early-exponential phase of growth almost all the enzyme was in the high-activity form, whereas during the stationary phase the highly active and the less active forms existed in equal amounts. These findings suggest that inorganic pyrophosphatase in S. faecalis is synthesized constitutively and is primarily regulated at the level of activity.

Culture Media↗
PubMed1981

Haemodynamic responses to antagonism of pancuronium and alcuronium block.

Using non-invasive methods, haemodynamic responses to antagonism of pancuronium (Pc) and alcuronium (Ac) block were compared in patients anaesthetized with thiopental-N2O-fentanyl and undergoing minor surgery. Neuromuscular block (90%) was maintained with Pc in 10 patients and Ac in 10 patients. After surgery, atropine 0.015 mg kg-1 and neostigmine 0.03 mg kg-1 (AN) were given simultaneously. The rate of reversal of the block was equal in the two groups. Between 4 and 16 min after AN, the decrease of heart rate (HR) was more pronounced in patients who had received Pc. The mean of the lowest HR was 43.2 beats min-1 in the Pc group, compared with 62.0 beats min-1 in the Ac group. The bradycardia was associated with a moderate decrease in arterial pressure in patients treated with Pc. However, due to an increase in stroke volume, mean cardiac output (CO) was not lower in the Pc group. Some patients treated with Pc developed a temporary nodal rhythm after AN and this was associated with a considerable decrease in CO. It is concluded that, in spite of marked bradycardia during antagonism of Pc block, circulation is well maintained, provided that sinus rhythm is present.

Adult↗
PubMed1981

Comparison of haemodynamic effects of pethidine and anileridine in anaesthetised patients.

Haemodynamic effects of equianalgesic doses of pethidine (1 mk kg -1) and anileridine (0.25 mg kg -1) were compared in patients with coronary artery disease, after induction of anaesthesia with flunitrazepam - N2O - pancuronium. Contrary to previous findings made in conscious patients, these analgesics produced a moderate circulatory depression. Heart rate, cardiac index and rate-pressure product were decreased by both drugs, and anileridine alone decreased mean arterial pressure. The only statistically significant differences in the haemodynamic changes between the two groups were those in pulmonary capillary wedge pressure and rate pressure product, which were slightly lower after anileridine than after pethidine.

Anesthesia↗
PubMed1981

Reversible changes in the activity of inorganic pyrophosphatase of Streptococcus faecalis. The effect of compounds containing SH-groups.

The activity of inorganic pyrophosphatase (EC 3.6.1.1) from Streptococcus faecalis ATCC 8043 decreased rapidly, when the cell extracts prepared by lysozyme and osmotic shock were incubated in a buffer solution (pH 8.0) at 25-50 degrees C. Increase in pH (from 8.5 to 10.5) retarded the inactivation considerably. The low activity level was reached in 2.5 h at 37 degrees C (pH 8.0) and this residual activity was stable during prolonged incubation. The enzyme in the form of low activity was not rapidly denatured until at 70 degrees C. The inactivation could be prevented and reversed by cysteine, dithiotreitol and 2-mercaptoethanol, but reductants, which do not contain SH-groups were not effective. Reduced glutathione slowed down and oxidized glutathione stimulated the inactivation. With pure enzyme it was shown that the low, stable activity level obtained with crude extracts during incubation is a property of inorganic pyrophosphatase and not due to another enzyme with a low capacity to hydrolyze inorganic pyrophosphate. These findings suggest that inorganic pyrophosphatase form S. faecalis exists in two interconvertible forms which differ in activity.

Bacteriological Techniques↗
PubMed1980

Comparison of haemodynamic effects of metocurine and pancuronium in patients with coronary artery disease.

The haemodynamic effects of large bolus doses of metocurine 0.45 mg kg-1 and pancuronium 0.1 mg kg-1 were compared in patients with coronary artery disease anaesthetized with diazepam, anileridine and nitrous oxide. Hypotension occurred more frequently after metocurine and was a result of a decrease in systemic vascular resistance. After pancuronium there was no increase in arterial pressure or heart rate, but a small increase in cardiac index. The decrease in heart rate after metocurine was the principal cause of the statistically significant difference in cardiac index between the two groups. Contrary to previous findings, metocurine did not attenuate circulatory responses to tracheal intubation. During surgical stimulation, two of the 10 patients of the pancuronium group developed significant ST segment depression and three patients had a rate-pressure product greater than 12 000 mm Hg beat min-1. However, the difference in rate-pressure product between the groups was not statistically significant.

Anesthesia, General↗
PubMed1980

General anesthesia in "inducible" porphyrias.

To evaluate the risk of inducing acute symptoms after general anesthesia in patients with "inducible " porphyrias, the authors analyzed retrospectively the effects of 78 exposure to anesthesia in 47 patients, 33 with acute intermittent porphyria and 14 with variegate porphyria. On 62 occasions, 29 involving the use of a barbiturate, anesthesia was induced in 37 patients who had no porphyric symptoms at the time. None of these patients had an acute attack postoperatively. Anesthesia was induced 16 times in 14 patients during acute episodes; 12 of these patients also received precipitating drugs other than anesthetics. Porphyric symptoms worsened in seven in the ten patients who received thiopental and in two of the four who did not. In the latent stages of acute intermittent and variegate porphyria in this patient population, the risk of incurring symptoms after exposure to thiopental and/or other anesthetics was small. During an acute episode thiopental may aggravate porphyric symptoms.

Acute Disease↗
PubMed1980

Lidocaine concentration in blood after topical anaesthesia of the upper respiratory tract.

The venous blood concentration of lidocaine was determined after stepwise application of lidocaine spray (270 mg) to the upper respiratory tract in 10 patients scheduled for bronchography, and after oropharyngeal application (150 mg) to five intubated patients under general anaesthesia. The peak level of lidocaine (about 1 microgram)ml/occurred 20--30 min after spraying in the bronchography group, while there was a level plateau at about 0.5 microgram/ml after oropharyngeal application of the local anaesthetic. There was great variation in the lidocaine concentration in both groups, but the highest observed concentration, 2.7 micrograms/ml, was safely below the toxic level. The mean rise in systolic and diastolic blood pressures at the various stages of spraying and on passing the bronchography tube in the local anaesthesia patients was 14.5--17.5/6.5--11 mmHg (1.9--2.3/0.9--1.5 kPa) compared to preanaesthetic values. In a similar group of patients, also scheduled for diagnostic bronchography, thiopentone anaesthesia, succinylcholine relaxation and laryngotracheal lidocaine spray resulted in a peak blood pressure increase of 36.5/27 mmHg (4.9/3.6 kPa) on passing the tube. The mean increases in pulse rate (21--26/min) were similar in both bronchography patient groups. No serious cardiac arrhythmias were observed in any of the patients.

Absorption↗
PubMed1979

Aeration sensitizes Streptococcus faecalis to hydroxyurea.

Hydroxyurea in up to 60 mM concentration did not inhibit growth or DNA synthesis in nonaerated cultures of Streptococcus faecalis ATCC 8043. In contrast, in cultures aerated by shaking already 1 mM hydroxyurea decreased the rate of net DNA synthesis and in higher concentrations of the drug the growth of the total cell mass also slowed down and the number of cells per chain increased from 1-2 to 10. The differential rate of DNA synthesis, but not the growth of the total cell mass, could be restored almost to the control level by adding thymidine to the medium. Thus there are at least two targets for hydroxyurea in the cells of S. faecalis grown in aerated cultures.

Air↗
PubMed1978

Inhibitors of DNA synthesis cause excessive DNA synthesis in dnaA mutants of Escherichia coli K12.

The relative rate of net DNA synthesis was stimulated when cells of dnaA mutants of Escherichia coli K12 were grown in the presence of low concentrations of DNA synthesis inhibitors. This led to a supernormal DNA/cell mass ratio. The excessive DNA was similar to the normal chromosomal DNA in size and stability in vivo. However, the cells did not divide but turned into long filaments. Excessive DNA synthesis in the presence of inhibitors of DNA synthesis was observed in the cultures of two independent dnaA mutants of E. coli, but dnaB and dnaC mutants behaved like the wild type in this respect.

DNA Replication↗
PubMed1977

Bradycardia during antagonism of pancuronium-induced neuromuscular block.

Heart rate was compared in matched patients during antagonism of neuromuscular block induced by tubocurarine, pancuronium or alcuronium with neostigmine 0.03 mg kg-1 preceded by atropine 0.015 mg kg-1. The frequency of bradycardia was greater during antagonism of pancuronium compared with alcuronium. Although there was a difference between the group receiving pancuronium and that receiving tubocurarine, it was not statistically significant. The decrease in heart rate was more rapid and profound in the pancuronium group; seven of the 15 patients who received pancuronium required an additional dose of atropine as compared with only one patient who received tubocurarine. However, the difference in heart rate between those who received pancuronium and those receiving tubocurarine was short-lasting, whereas the heart rate of those who received alcuronium was higher than that in the other groups during the entire 60-min period of observation. The findings with pancuronium may be a result of its inhibitory effect on serum cholinesterase.

Adult↗
PubMed1976

Adaptation of the cells of Escherichia coli to the presence of hydroxyurea increases the level of inorganic pyrophosphatase acttivity.

Hydroxyurea, an inhibitor of ribonucleoside diphosphate reductase, completely arrested the net synthesis of DNA for 3-4 h, when it was added in 30 mM concentration to growing cultures of Escherichia coli K12. Thereafter the net synthesis of DNA started again, although slowly, and simultaneously with it the formation of inorganic pyrophosphatase activity was stimulated leading to a 2-fold increase in the specific activity of the enzyme in 2-3 h. Subsequently cell division began again. In this way a new steady state, stable in the presence of hydroxyurea, was reached. This new state was characterized by the high specific activity of inorganic pyrophosphatase, a small but constant amount of DNA/cell mass (1/4 of the normal value), and large elongated cells. All these changes were slowly reversed during 5-6 h, when the cells were transferred into a drug-free medium. The activity of isoleucyl-tRNA synthetase, assayed as a control, did not change significantly in the presence of hydroxyurea. Hydroxyurea had no effect on the activity of inorganic pyrophosphatase in vitro.

Chloramphenicol↗
PubMed1976

Comparison of haemodynamic effects of pethidine and anileridine in patients with coronary-artery disease.

The circulatory effects of anileridine, a derivative of pethidine, have been little studied. Therefore we compared the haemodynamic effects of equianalgesic doses of pethidine (1 mg/kg i.v.) and anileridine (0.25 mg/kg) in matched patients requiring myocardial revascularization. Cardiac output was significantly increased 5 min after the administration of pethidine, mainly due to an increase in heart rate. A transient rise in the systolic pulmonary-arterial pressure was found after anileridine. No remarkable changes were found in systemic arterial pressures, central venous pressure, balloon-occluded pulmonary-arterial pressure, stoke volume, systemic or pulmonary vascular resistances and derived oxygen consumption. Further, 20 min after drug administration, there were no significant differences in any circulatory parameters between the two groups. One patient developed acute cardiac failure after anileridine, though as he had very severe coronary heart disease it remains an open question whether this was spontaneous or drug-induced. Since the rate-pressure product tended to increase after pethidine, this drug may not be considered an ideal analgesic for patients with ischaemic heart disease. Anileridine had less influence on this variable. Since the circulatory effects of pethidine seem to depend on the haemodynamic status of the patient, the haemodynamic properties of anileridine may also deserve further investigation.

Adult↗