Search PubMed⌕ Search

Biomedical subjects

M Tuominen

Publications and source records attributed to M Tuominen.

At least 73 records · Page 4Linked to original sources
PubMed1990

Adrenal cortex contributes to the regulation of NaCl-stimulated ANP release in the rat.

The present study documents the effects of hypophysectomy and the effects of dexamethasone substitution on the NaCl-stimulated release and on the basal secretion rates of ANP from the rat atria in vitro. We also measured the concentration of mRNA in the atria after hypophysectomy. Rats (n = 12) were subjected to hypophysectomy by a parapharyngeal approach. One group of rats (n = 6) received dexamethasone 0.2 mg s.c. daily for 4 weeks, while the other group was left unsubstituted. After 4 weeks, the atrial block (n = 10) was excised, placed in an organ bath (field stimulation 4 s-1, 20 V, 1 ms; resting tension = 5 mN) and superfused (7 ml min-1) either with a physiological buffer solution (295 mosmol kg-1) or with a hyperosmotic NaCl solution (330 mosmol kg-1). The atria from the hypophysectomized rats did not respond to the stimulus: the concentration of ANP in the 1-min samples of the perfusate was under 100 pg ml-1. Dexamethasone treatment significantly (P less than 0.05) increased the ANP concentration to a maximum of 165 +/- 17 (mean +/- SEM) pg ml-1 during the superfusion while the control concentration was 110 +/- 19 pg ml-1. The ANP mRNA/18 S RNA ratios did not differ between the atria of hypophysectomized and control rats. In conclusion, glucocorticoids are required in the stimulus-induced release of ANP and the impaired release of ANP after hypophysectomy does not depend on an impaired synthesis of ANP.

Adrenal Cortex↗
PubMed1990

Continuous interscalene brachial plexus block during and after shoulder surgery.

Continuous interscalene brachial plexus block with a single dose of 0.75% bupivacaine (150-210 mg) with adrenaline, continued with an infusion of plain 0.25% bupivacaine 0.25 mg/kg/h, was performed on 20 patients to provide analgesia during shoulder surgery and in the postoperative period. The control group included 20 patients who were given general anaesthesia for surgery after starting a continuous interscalene brachial plexus block; test dose of 0.75% bupivacaine (22.5 mg) with adrenaline, continued with an infusion of 0.25% bupivacaine 0.25 mg/kg/h. Surgery was performed successfully under regional anaesthesia in 16/20 patients; 4/16 were given one dose of fentanyl during the surgery, and diazepam or midazolam as supplementary sedation were given in 13/16 cases. For postoperative analgesia 35/40 patients had a fully functioning catheter for 20-26 hours and the need for oxycodone i.m. during that time was 1.5 +/- 0.4 doses after regional anaesthesia (n = 14) and 1.8 +/- 0.4 doses after general anaesthesia (n = 18). There was a statistically significant difference in the mean plasma bupivacaine concentrations between the groups, concentrations in the regional anaesthesia group being higher at 5, 30, 60 min and 3 h (maximum 2.3 micrograms/ml at 60 min), but there was no difference between the values at 24 h. One infusion of local anaesthetic was discontinued because of probable treatment-related side-effects (breathing difficulties, nausea). Mild local anaesthetic toxicity (dizziness, tinnitus) was noticed in four patients.

Analgesia↗
PubMed1989

Spread of spinal anaesthesia with plain 0.5% bupivacaine: influence of the vertebral interspace used for injection.

Three millilitre of plain 0.5% bupivacaine was injected intrathecally at two different levels in two groups of 20 patients. Injection at the L2/3 space produced a significantly higher spread of analgesia (mean T7 (SD 3.9)) than injection at L4/5 (T11(1.8)). The range of the cephalad spread of the block was less in the L4/5 group (P less than 0.001 at 60 min). The spread of anaesthesia continued beyond 30 min in both groups. In all patients anaesthesia sufficient for surgery of the knee and the foot was achieved. One patient had a final block level of T1 after injection at L2/3, accompanied by transient arterial hypotension.

Adult↗
PubMed1989

Individual predictability of repeated spinal anaesthesia with isobaric bupivacaine.

To evaluate the individual predictability of the spread of spinal anaesthesia, an analysis of 38 patients who had had at least two spinal blocks within 4 years was performed. All spinal blocks were done with the patients in the lateral position at the midline in the interspace LIII-IV, injecting 3 ml of isobaric 0.5% bupivacaine. Regression analysis showed that the predictability of the maximal analgesic spread of the second anaesthesia from the first anaesthesia was highly significant (P less than 0.0001). Therefore, if a higher or lower level of the block is required, another method for the forthcoming anaesthesia may be needed. The reasons for this phenomenon could not be clarified in this retrospective study.

Adolescent↗
PubMed1989

Continuous interscalene brachial plexus block: clinical efficacy, technical problems and bupivacaine plasma concentrations.

Continuous interscalene brachial plexus block with a single dose of 0.5% bupivacaine 1.25 mg/kg, continued with an infusion of 0.25% bupivacaine 0.25 mg/kg/h, was performed on 24 patients to provide analgesia during shoulder surgery and in the postoperative period. The drugs for general anaesthesia included glycopyrrolate, thiopentone, vecuronium, enflurane and N2O/O2. All patients had signs of regional analgesia 30 min after the block without haemodynamic problems. The infusion of local anaesthetic was interrupted in six patients because of a failure in catheter function. Of the remaining 18 patients, nine needed no complementary analgesics and nine patients received, on average, 1.6 doses of oxycodone (0.15 mg/kg/dose) during a 24-h period. Displacement of the interscalene catheters could be prevented by a fixation suture to the skin. Two patients noted a metallic taste during the bupivacaine infusion. The most common complaints were numbness of the hand (n = 15) and hoarseness (n = 5). The mean (+/- s.e.mean) plasma concentrations of bupivacaine at 30, 60, 180 min and 24 h were 0.68 +/- 0.06, 0.62 +/- 0.05, 0.52 +/- 0.04 and 0.76 +/- 0.01 micrograms/ml, respectively. During the 24-h period, the alpha 1-acid glycoprotein (AAG) concentration (mean +/- s.e.mean) in plasma rose from 0.41 +/- 0.04 g/l to 0.54 +/- 0.04 g/l (P less than 0.001). The concentration of free bupivacaine was below detectable levels (less than 0.01 micrograms/ml) after the 24-h infusion. The rise in AAG probably increases binding of bupivacaine to plasma proteins, diminishing the risk of systemic toxicity.

Brachial Plexus↗
PubMed1989

Effects of oral clonidine premedication on concentrations of cortisol and monoamine neurotransmitters and their metabolites in cerebrospinal fluid and plasma.

Forty-two healthy male patients (aged 19-40 years), undergoing orthopaedic surgery under spinal anaesthesia (3 ml isobaric 0.5% bupivacaine), were given clonidine 4.5 micrograms kg-1 orally either 2 (Group I, n = 10) or 4 (Group II, n = 10) hours before the operation, diazepam 0.15 mg kg-1 orally (Group III, n = 10) or a placebo tablet (Group IV, n = 12) 2 h before the operation. Plasma concentrations of cortisol, noradrenaline (NA), adrenaline (A), 3,4-dihydroxyphenylglycol (DHPG) and dihydroxyphenylacetic acid (DOPAC) were assayed from venous blood samples just before premedication and just before the spinal block. Cerebrospinal fluid (CSF) concentrations of cortisol, tryptophan, 5-hydroxyindoleacetic acid and catecholamine metabolites were assayed from a sample taken before the spinal block. The plasma NA concentrations of the patients in the groups receiving clonidine decreased clearly compared with the other groups (P less than 0.05). The NA metabolite DHPG was also lower in Groups I and II than in Group III (P less than 0.05) after premedication. Plasma A concentrations were lower in Groups I and III than in Group IV (P less than 0.05). The CSF concentrations of the different substances were similar in all groups. In Group I the sensory blockade lasted significantly longer than in Group III (P less than 0.05) and the mean duration of motor blockade was longer in Group I than in Groups III and IV (P less than 0.05). Two patients in both clonidine groups developed bradycardia (heart rate less than 45 min-1) requiring atropine treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

3,4-Dihydroxyphenylacetic Acid↗
PubMed1989

Spread of spinal anaesthesia using various doses of plain 0.5% bupivacaine injected at the LIV-V interspace.

Spinal anaesthesia with 3 ml, 4 ml or 5 ml of plain 0.5% bupivacaine was performed in three groups of 20 orthopaedic (ASA 1) patients at the LIV-V interspace. Patients aged less than 20 years or more than 60 years and those outside the normal range of body mass index were excluded. The spread of analgesia was greater in the 4-ml and 5-ml groups compared to the 3-ml group at each testing time (P less than 0.05). The mean maximum cephalad spread of pinprick analgesia (+/- s.d.) 60 min after injection was significantly higher (P less than 0.05) in the 4-ml group (T10 +/- 3.2) and in the 5-ml group (T10 +/- 2.7) than in the 3-ml group (T12 +/- 2.1). The interindividual variability of the cephalad spread of analgesia was greater in the 4-ml and 5-ml groups compared to the 3-ml group (P less than 0.05). The degree of motor block was higher in the 5-ml group than in the 3- and 4-ml groups at 5 and 15 min after injection. In seven patients the first sign of motor block was the patient's inability to flex the ankle, rather than inability to raise an extended leg as was the case in the other patients. In all patients satisfactory anaesthesia for surgery of the lower extremity was achieved.

Adult↗
PubMed1989

Association between acid fumes in the work environment and dental erosion.

The effect of inorganic acid fumes from the work environment on the erosion of teeth was studied blindly. A sample of 186 workers was drawn from four factories. Among the 157 dentulous participants, 76 were working in departments containing acid fumes, and 81 had never worked under such conditions and were used as referents. Of the acid workers 18.4% had one or more teeth with erosion, and the corresponding figure for the referents was 8.6%. With a longer duration of exposure the proportion of subjects with erosion increased. The acid workers had more teeth with erosion than the referents, especially upper anterior teeth. The findings suggest that even today exposure to inorganic acid fumes from the work environment may increase the erosion of teeth, especially the upper anterior teeth, which are not continuously protected by saliva and the lips.

Adult↗
PubMed1988

The concentration of atrial natriuretic peptide (ANP) is decreased in plasma but not in atria in hypophysectomised rats.

To study the role of the pituitary gland in the release of Atrial Natriuretic Peptide (ANP) plasma and atrial concentrations were measured both in intact and in hypophysectomized rats. The plasma concentration of ANP (pg/ml) was significantly (p less than 0.01) decreased from 143 +/- 35 to 82 +/- 29 (mean +/- SD, n) while the tissue concentration (ng/wet tissue mg) remained unchanged, 192 +/- 46 and 194 +/- 39, respectively. The total atrial amount of ANP (ug) was, however, significantly (p less than 0.01) decreased from 29.7 +/- 7.8 to 17.0 +/- 3.3 after hypophysectomy. In intact animals, a volume load (1.1ml/100 body weight g 0.9% NaCl) resulted in 2-fold (p less than 0.001) increase in the plasma ANP levels whereas similar load had no effects on plasma ANP levels in hypophysectomized animals. In both groups, the right atrial pressure was increased from about 2 to about 6 mmHg. We conclude that in the absence of pituitary gland the right atrial pressure and the atrial ANP concentration do not change but plasma ANP levels and the response to volume stimulus are attenuated.

Animals↗
PubMed1988

Intravenous indomethacin prevents venipuncture inflammatory sequelae.

One hundred general or orthopaedic surgery patients (ASA I-II) were randomly given either indomethacin (25-50 mg bolus plus infusion, 5-7.5 mg h-1) in lactated Ringer solution intravenously in one hand and only lactated Ringer solution into a corresponding vein of the other hand (50 patients) or only lactated Ringer solution intravenously in both hands (50 patients), starting before anaesthesia induction and ending at 7 a.m. the following morning. All anaesthetic drugs were given equally divided into both drips. The need for additional analgesia as well as venipuncture and infusion sequelae were registered on the postoperative morning in a double-blind fashion. The mean +/- s.d. oxycodone dose in the postoperative observation period was lower in the indomethacin group (18 +/- 16 mg) than in the control group (27 +/- 20 mg) (n.s.). There was a lower number of patients requiring oxycodone more than once in the indomethacin group than in the control group (P less than 0.05). Fewer patients in the indomethacin group (22%) had inflammatory changes at the venipuncture site than in the control group (46%) (P less than 0.05). There was no difference between hands; i.e. in patients given indomethacin inflammatory changes were equally common in both hands. No thrombophlebitic complications developed, which was confirmed by a mailed questionnaire (response 96/100) 2 weeks after surgery.

Adult↗
PubMed1988

Efficacy of 0.3 mg morphine intrathecally in preventing tourniquet pain during spinal anaesthesia with hyperbaric bupivacaine.

Tourniquet-induced pain is probably mediated by C-fibres. The ability of morphine to interrupt this nociceptive conduction was studied in a double-blind fashion by administering either morphine 0.3 mg or saline intrathecally along with hyperbaric bupivacaine 15 mg for spinal anaesthesia in 40 patients undergoing orthopaedic surgery on the lower extremity. The block characteristics were similar in both groups. During surgery, no patient in the morphine group complained of pain, whereas in the saline group one patient complained of pain caused by the tourniquet and two other patients experienced surgical pain. A 60-min experimental thigh tourniquet pressure provocation (53 kPa for 20 min; 0 kPa for 20 min; 53 kPa for 20 min) on the contralateral unoperated extremity was then performed following surgery, when the spread cephalad of the sensory block had decreased below the T10 dermatomal level. Eight patients in the morphine group experienced no pain in this test, compared with two patients in the saline group (P less than 0.05). The remaining 12 patients in the morphine group had pain responses similar to those patients not given morphine. Intrathecal morphine provides a level of prophylaxis against tourniquet pain. However, the dosage employed here was associated with urinary and emetic side-effects.

Adult↗
PubMed1987

Postoperative pain relief and bupivacaine plasma levels during continuous interscalene brachial plexus block.

Interscalene brachial plexus block was performed on 40 patients for prophylactic pain relief after shoulder surgery. A dose of 1.25 mg/kg of 0.5% bupivacaine was injected for the block (Group 1) and continued with an infusion of 0.25% bupivacaine 0.25 mg/kg/h (Group 2). If the postoperative analgesia was insufficient, the patients received i.m. oxycodone 0.15 mg/kg. In Group 1, one patient managed without oxycodone supplementation during the 24-h observation period compared with eight patients in Group 2 (P less than 0.01). The rest of the patients received 3.8 +/- 1.6 doses (Group 1) and 2.5 +/- 1.2 doses (Group 2) of oxycodone (P less than 0.05). At 30 min, the mean bupivacaine plasma concentration was 1.0 microgram/ml in Group 1 and 0.9 microgram/ml in Group 2. The mean plasma level of bupivacaine increased from 0.7 microgram/ml after 180 min to 1.1 micrograms/ml (P less than 0.01) after 24 h of infusion, providing some evidence of accumulation during infusion. The dizziness and confusion experienced by three patients could be associated with the local anaesthetic, as they obtained relief after the infusion was stopped.

Adolescent↗
PubMed1987

Spinal anaesthesia with hyperbaric tetracaine: effect of age and body mass.

To discover the influence of age and body mass on spinal analgesia with hyperbaric tetracaine, 60 patients (17-82 years) were administered a subarachnoid injection of 15 mg tetracaine in 3 ml of 5% glucose. The patients were in the lateral position during the injection and in the supine position thereafter. The maximal spread of analgesia (mean T4, range T1-T11) did not correlate with age or body mass. Any variable studied was not significantly different for the different age groups. In 29 patients (48%) the block required supplementation with fentanyl or general anaesthesia (five patients). Tourniquet-induced pain occurred in eight patients (28% of patients with tourniquet). Decreases in systolic arterial blood pressure, greater than 30% of the preanaesthetic value, correlated with the level of analgesia and were more frequent in patients over 50 years (P less than 0.01). Severe hypotension and bradycardia with transient serious changes in QRS-complexes occurred in one patient (analgesia level, T3). In conclusion, 15 mg of hyperbaric tetracaine provided a relatively high sensory spinal blockade without correlating with age or body mass. Supplementation of analgesia during surgery was needed in almost half of the patient material.

Adolescent↗
PubMed1987

Peptides and neurotransmission in the central nervous system.

Radioimmunoassays of brain extracts have shown that several peptides occur in high concentrations in the CNS. The releasing-factor peptides TRF, LRF, somatostatin, CRF and GRF have the highest concentration in the hypothalamic extracts. High levels of somatostatin, CCK octapeptide, neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) are found in cortical extracts. Substance P, CCK, NPY, and enkephalins are present in high concentrations in basal ganglia and mesolimbic areas. Pharmacological doses of these peptides result in several behavioural and vegetative effects. Immunocytochemical studies show that the CNS peptides are localised in neurones and in synaptic vesicles. In vitro studies with brain tissues show that peptides are capable of modifying the ongoing classical neurotransmission. In depressive patients several neuropeptides (CCK, CRF and NPY) have been shown to have low CSF levels. Patients dying of senile dementia have low cortical levels of somatostatin, CRF and substance P. In schizophrenic patients CCK peptides have shown to improve some symptoms. At present the therapeutic potentials of peptides are poorly known. More studies are required to understand their role in neurotransmission and related pathological states.

Animals↗
PubMed1986

Some cardiovascular and metabolic effects of repeated sauna bathing.

Ten healthy male volunteers were exposed to the dry heat of a Finnish sauna (+80 degrees C) for 1 h twice a day for a period of 7 days. After each exposure rectal temperature rose by 0.8-1.1 degrees C and body weight dropped by 0.7-0.9 kg. The systolic blood pressure recorded 3-5 min after the sauna did not change during the experiments but the diastolic blood pressure decreased by 7-37 mmHg (P less than 0.05). The pulse rate rose from 75-80 to 106-116 beats min-1 (P less than 0.05) after the sauna. The increased responses of pulse and temperature adapted to heat exposures so that they were significantly lower after the 3rd day (rectal temperature) or after 6th day (pulse). Metabolic rate increased by 25-33% (P less than 0.01) after the first day. Serum total proteins, Hb and Htc were significantly increased on the 1st and 3rd days but not later, although the dehydration in response to sauna was unchanged as judged from the weight losses. Serum K, Na and Fe were significantly decreased on the 3rd and 7th day indicating that special attention should be given to the electrolyte balance in long-lasting intense heat exposure. No ECG changes were found in recordings taken on the 7th day.

Adult↗
PubMed1986

Endocrine effects of repeated sauna bathing.

Ten healthy male and seven female volunteers were exposed to dry heat (in a Finnish sauna 80 degrees C) 1 h twice a day for 7 days. The levels of ACTH in plasma, cortisol, TSH, thyroid hormones, testosterone, gonadotropins, prolactin and GH in serum and urinary excretion of catecholamines were determined before the experiment, and on the first, third and seventh days. Females participated only in prolactin studies. During the experiments there were no statistically significant changes in serum thyroid hormones, TSH, testosterone, FSH and LH levels. Serum cortisol and plasma ACTH decreased and urinary catecholamine increased slightly at the end of the experiment (P less than 0.05). Serum GH and prolactin in males exhibited 16- and 2.3-fold increases (P less than 0.01), respectively. In females serum prolactin rose over four-fold (P less than 0.01). The GH rise in response to hyperthermia declined after the third day but prolactin remained elevated at the end of the experiments in males. The release of prolactin in females was also high and may be associated with the transient amenorrhoea that occurred in five out of seven subjects after the experiment. The increased release of prolactin and perhaps that of GH may be associated to the heat-exposure-induced dehydration.

Adrenal Cortex Hormones↗
PubMed1986

Droperidol, alizapride and metoclopramide in the prevention and treatment of post-operative emetic sequelae.

Women (182) undergoing elective orthopaedic surgery under general anaesthesia received 100 or 200 mg alizapride, 1.25 mg droperidol, 20 mg metoclopramide or a saline placebo intravenously 5-10 min before the end of anaesthesia in a double-blind random fashion to prevent post-operative nausea and vomiting. Administration of the same anti-emetic was repeated during 24 h post-operatively if the patient complained of nausea or retched or vomited. Significantly fewer patients given any of the anti-emetics prophylactically were nauseated or vomited in comparison with patients given saline. The incidence of nausea and vomiting in the saline group was 83%, while in those patients who received an anti-emetic it was as follows: droperidol 35% (P less than 0.001 vs. saline), alizapride, 100 mg 46% (P less than 0.01), alizapride 200 mg 53% (P less than 0.05) and metoclopramide 58% (P less than 0.05). The number of patients needing an additional dose of the same substance in the post-operative period was significantly higher in the saline group (67%) than in the groups which had received droperidol (32%, P less than 0.01) and alizapride 100 mg (37%, P less than 0.05) or 200 mg (33%, P less than 0.05). The patients who received metoclopramide, however, did not differ statistically from the saline group in the treatment of nausea and vomiting. It is concluded that droperidol was the most effective, and metoclopramide the least effective, anti-emetic in this study.

Adolescent↗