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Biomedical subjects

M Salonen

Publications and source records attributed to M Salonen.

At least 19 recordsLinked to original sources
PubMed2002

Reducing the risk of systemic embolization during gynecologic laparoscopy--effect of volume preload.

BACKGROUND: About 27% of the population is known to have a patent foramen ovale. It can be opened if the left atrial pressure is less than the right atrial pressure. This pressure reversal has been reported during gynecologic laparoscopic surgery. The present paper describes with help of transesophageal echocardiography the pressure relationship between the atria during laparoscopic surgery and the effect of volume preload. METHODS: Twenty-one gynecologic ASA 1-3 patients were included in this open study. The movement of interatrial septum was monitored with transesophageal echocardiography during the procedure. If the septum movement was to the left, the patient was given 500 mL hydroxyethyl starch to increase the filling pressures. RESULTS: After induction, the mobile part of foramen ovale rounded to the right in 15 patients but six patients showed movement to the left. After pneumoperitoneum and head-down tilt, one patient of the six returned to normal but eight additional patients showed movement to the left. These 13 patients had a filling infusion of 500 mL hydroxyethyl starch. The movement was normalized in 12 patients. We saw echogenic particles coming from the inferior caval vein in every patient. Only one patient had very small atrial septal defects and no embolic complications. CONCLUSION: The head-down tilt and pneumoperitoneum had a more negative influence on the filling of the left side than on the filling of the right side of the heart. The pressure reversal occurs in systole during expiration of mechanical ventilation. The infusion of volume helps to normalize the pressure relationship and to diminish the embolic risk.

Adult↗
PubMed2000

A comparison of the hemodynamic effects of paracervical block and epidural anesthesia for labor analgesia.

BACKGROUND: Both paracervical block (PCB) and epidural analgesia are sometimes associated with hemodynamic effects potentially harmful to the well-being of the fetus. Our study was designed to test the hypothesis that PCB would have a more profound effect on maternal and fetal blood flow than epidural analgesia. METHODS: Forty-four healthy primiparous parturients were randomized to receive either PCB (n=21) or epidural analgesia (n= 23) with 25 or 30 mg of bupivacaine, respectively, for labor analgesia. Maternal blood pressure and fetal heart rate were recorded. Blood flow was measured using a color Doppler device. The blood flow measurements consisted of assessment of the pulsatility indices (PI) of the right maternal femoral artery and the main branch of the uterine artery (placental side), the umbilical artery and the fetal middle cerebral artery. The measurements were performed before administration of analgesia and approximately 15-20 min later after the onset of analgesia. RESULTS: Both methods provided in general good analgesia, but rescue medication was required more often after PCB. Epidural analgesia decreased maternal blood pressure more than PCB and the PI of maternal femoral artery decreased after onset of epidural analgesia, indicating epidural-induced vasodilation. The PI of the uterine artery increased after the onset of PCB, indicating vasoconstriction of this artery. No significant adverse effects or differences in the well-being of the newborn were observed, as indicated by similar Apgar scores and pH-status. CONCLUSION: There were small differences in the effects of PCB and epidural analgesia on uteroplacental circulation as well as on maternal hemodynamics. PCB may have a vasoconstrictive effect on the uterine artery. This and the fact that the parturients required rescue analgesia more frequently after PCB than after epidural block speaks for the feasibility of the latter in obstetrics.

Adult↗
PubMed1997

Phosphorylation of light-harvesting complex II and photosystem II core proteins shows different irradiance-dependent regulation in vivo. Application of phosphothreonine antibodies to analysis of thylakoid phosphoproteins.

An immunological approach using a polyclonal phosphothreonine antibody is introduced for the analysis of thylakoid protein phosphorylation in vivo. Virtually the same photosystem II (PSII) core phosphoproteins (D1, D2, CP43, and the psbH gene product) and the light-harvesting chlorophyll a/b complex II (LHCII) phosphopolypeptides (LHCB1 and LHCB2), as earlier identified by radiolabeling experiments, were recognized in both pumpkin and spinach leaves. Notably, the PSII core proteins and LHCII polypeptides were found to have a different phosphorylation pattern in vivo with respect to increasing irradiance. Phosphorylation of the PSII core proteins in leaf discs attained the saturation level at the growth light intensity, and this level was also maintained at high irradiances. Maximal phosphorylation of LHCII polypeptides only occurred at low light intensities, far below the growth irradiance, and then drastically decreased at higher irradiances. These observations are at variance with traditional studies in vitro, where LHCII shows a light-dependent increase in phosphorylation, which is maintained even at high irradiances. Only a slow restoration of the phosphorylation capacity for LHCII polypeptides at the low light conditions occurred in vivo after the high light-induced inactivation. Furthermore, if thylakoid membranes were isolated from the high light-inactivated leaves, no restoration of LHCII phosphorylation took place in vitro. However, both the high light-induced inactivation and low light-induced restoration of LHCII phosphorylation seen in vivo could be mimicked in isolated thylakoid membranes by incubating with reduced and oxidized dithiothreitol, respectively. We propose that stromal components are involved in the regulation of LHCII phosphorylation in vivo, and inhibition of LHCII phosphorylation under increasing irradiance results from reduction of the thiol groups in the LHCII kinase.

Chloroplasts↗
PubMed1996

Quantitative determination of bovine serum haptoglobin in experimentally induced Escherichia coli mastitis.

A high performance liquid chromatography (HPLC) method was developed, validated and used to analyse haptoglobin concentrations in serum samples taken from eight cows which had been challenged twice intramammarily with Escherichia coli. The results of the HPLC were compared with those from a photometric assay. The kinetics of the haptoglobin response were analysed with pharmacokinetic computer software. In contrast with the photometric assay, the HPLC was sufficiently sensitive to detect normal background levels of bovine serum haptoglobin. The serum haptoglobin concentrations of healthy cows ranged from 22 to 47 mg litre-1. As the concentration of haptoglobin increased, the results of the two methods correlated well (r = 0.96). A 52-fold increase in serum haptoglobin was detected after the first challenge with E coli. The mean pharmacokinetic parameters of the response after the first challenge were: lag phase 12 hours, t2/1increase 20 hours, tmax 72 hours, t1/2decrease 46 hours, and mean residence time 112 hours. The second challenge three weeks later resulted in a significantly lower haptoglobin response, the area under curve being 35 per cent of that after the first challenge. The clinical signs and inflammatory changes in the milk did not differ significantly between the challenges.

Animals↗
PubMed1996

Intra-articular morphine and saline injections induce release of large molecular weight proteoglycans into equine synovial fluid.

Both morphine and physiologic saline injected intra-articularly into healthy equine tarsocrural joints induced a release of large molecular size proteoglycan (PG) subunits into the synovial fluid (SF) analysed 24 h postinjection. High-performance liquid chromatography (HPLC) with a size-exclusion column was used to assess the high molecular weight proteoglycans in equine synovial fluid (SF). The PG peaks of SF samples eluated separately from SF hyaluronate and other molecular components of the SF in the HPLC chromatographies indicating no interaction between hyaluronate and PG in the SF. Individual elution profiles varied between joints and horses. The amount of PG release was measured by relative area index from the HPLC chromatograms. The synovial fluid PG content was significantly increased (P < 0.05) after morphine but not in saline injected joints compared with pretreatment but there were no significant differences between the two groups. It was concluded that intra-articular injections of both morphine and physiologic saline are able to elicit a marked PG release into the SF from articular cartilage within 24 h of injection.

Animals↗
PubMed1996

Disposition of enrofloxacin (Baytril) into the udder after intravenous and intra-arterial injections into dairy cows.

Enrofloxacin (Baytril) was injected into arteries supplying the udder of dairy cows. The idea was to avoid primary distribution, metabolism and elimination and thus to deliver the drug to the target organ at higher concentration. Enrofloxacin injected into the abdominal aorta or the external iliac artery resulted in high initial enrofloxacin retention by the udder and high milk concentrations. Injection of enrofloxacin into the abdominal aorta resulted in 2.2 times higher milk peak concentration of the drug than intravenous injection into the jugular vein. Injection of the drug into one of the two external iliac arteries allowed drug concentrations of milk from the udder halves to be compared: when enrofloxacin was injected into the right external iliac artery, the peak milk enrofloxacin concentration from the right udder half was 4.8 times that of the left udder half. The bulk of enrofloxacin was absorbed from the milk compartment of the udder before the next regular milking 6.5 h later. By this time, the metabolite ciprofloxacin had accumulated in milk. Pharmacokinetic values for enrofloxacin and its metabolite ciprofloxacin are given separately for serum and milk whey following three intravascular dosing routes.

Animals↗
PubMed1996

Hyaluronate and large molecular weight proteoglycans in synovial fluid from horses with various arthritides.

OBJECTIVE: To investigate the presence of large molecular weight (MW) proteoglycans (PG) and hyaluronate (HA) in synovial fluid (SF) from horses with various arthritides and from control joints. DESIGN: Horses with acute (< 2 weeks) or chronic (> 4 weeks) lameness were examined by clinical examination, intrasynovial anesthesia, radiography, arthroscopy, and SF analysis. Joints were grouped on the basis of diagnosis: acute traumatic arthritis, chronic traumatic arthritis (with a subgroup of degenerative joint disease), intra-articular fracture, and infectious arthritis. ANIMALS: 31 horses with arthritis and 9 control horses; altogether 43 SF samples were analyzed. PROCEDURE: High-performance liquid chromatography was used to assess HA and large MW PG in SF samples. RESULTS: A PG peak was identified in 8 of 23 SF samples of joints with chronic traumatic arthritis, 4 of which had no or minimal abnormal radiographic findings but mild articular cartilage fibrillation detected by arthroscopy, and in 3 joints with intra-articular fracture and 1 with resolving infectious arthritis, but not in joints with acute traumatic arthritis or in control joints. There was significant difference (P < 0.01) in mean (+/- SEM) HA concentration between control joints and joints with chronic traumatic arthritis (0.32 +/- 0.04 g/L; n = 9 vs 0.18 +/- 0.01 g/L; n = 23). CONCLUSION: Large MW PG fragments are released into equine SF in the course of articular disease and can be detected simultaneously with HA by high-performance liquid chromatography. CLINICAL RELEVANCE: The SF HA concentration can be used as diagnostic marker for chronic traumatic arthritis. However, SF PG or other marker cannot be used for diagnosing or monitoring degenerative joint disease.

Animals↗
PubMed1995

Pharmacokinetics of enrofloxacin after single intravenous, intramuscular and subcutaneous injections in lactating cows.

Five Ayrshire cows were given enrofloxacin (5 mg/kg body weight) intravenously (i.v.), intramuscularly (i.m.) and subcutaneously (s.c.). The antimicrobial activity was measured in milk and serum samples using the agar-diffusion technique. High-performance liquid chromatography (HPLC) assay was used to study the extent of metabolism of enrofloxacin to ciprofloxacin. Analysis of the serum concentration-time data was based on statistical moment theory. Mean t1/2 beta of antimicrobial activity in serum was 1.7, 5.9 and 5.6 h after i.v., i.m. and s.c. administration, respectively. Both i.m. and s.c. routes were associated with a marked flip-flop phenomenon. Based on HPLC analysis of serum samples, the half-lives of enrofloxacin and ciprofloxacin were approximately the same. A marked proportion of enrofloxacin was metabolized to ciprofloxacin. The enrofloxacin fraction bound in vitro to serum proteins was 36-45%. About 0.2% of the total enrofloxacin dose was found in milk during the first 24 h and the amount transferred did not depend on the route of administration. Based on the HPLC data, enrofloxacin concentration in milk was parallel to that in serum, while ciprofloxacin was concentrated in milk. After i.v. injection, the peak concentration of enrofloxacin in milk was reached between 0.7 and 1.3 h but occurred much later for ciprofloxacin (tmax 5-8 h). After i.m. and s.c. administration the concentration-time curves for both enrofloxacin and ciprofloxacin in milk were shallow and there were no obvious peaks.

Animals↗
PubMed1994

Forearm tremor in relation to selected physiological and body dimensional variables.

Interrelationships between forearm tremor and a number of body dimensional, muscle structure, muscular strength and training background variables were studied among 13 male students with athletic backgrounds. The subjects performed isometric dominant upper extremity elbow flexions with a 90 degrees joint angle and with the forearm held in a horizontal position. A freely hanging mass was attached via a strain gauge transducer, a metal chain and cuff to the forearm. An accelerometer attached to the cuff measured the vertical component of tremor. The power spectrum density function was calculated for a tremor acceleration signal and a bandwidth of 7-20 Hz was analysed in more detail. The right M. vastus lateralis was biopsed in order to determine the muscle fiber composition. Arm mass and muscle fiber composition were found to correlate statistically significantly with the tremor frequency characteristics. In the further analyses arm mass was found to be the only variable explaining the tremor frequency characteristics; the effects of the muscle structure variables were minor when the effects of arm mass was controlled in partial correlation analyses. Interindividual differences in motor unit firing properties were presumed to explain the dependence found between arm mass and tremor frequency.

Acceleration↗
PubMed1994

Concentration and molecular weight distribution of hyaluronate in synovial fluid from clinically normal horses and horses with diseased joints.

High molecular weight (MW) hyaluronate (HA) is an integral part of synovial fluid (SF), regulating many important physiologic and pathophysiologic mechanisms. Many of its effects depend on, or are reflected in, the concentration and MW of HA. High-performance liquid chromatography was used to assess simultaneously the concentration and MW of HA in SF obtained from horses with various arthritides: acute traumatic arthritis; chronic traumatic arthritis, including degenerative joint disease (DJD); and infectious arthritis. The size-exclusion column was calibrated, using appropriate HA concentration and MW standards, before the high-performance liquid chromatographic assays of the SF samples. Calibration of the column disclosed that the maximal limit for MW estimation of HA was around 3 million. In control joints, MW of HA ranged from 2 to 3 x 10(6) (mean 2.5 x 10(6)) and did not differ significantly from MW of HA in SF from horses with acute or chronic traumatic arthritis (mean 2 x 10(6); range 1.5 to 3 x 10(6)). Interestingly, a small amount of HA of moderately high MW (approx 1 to 1.5 x 10(6)) was detected in chromatograms of SF from infected joints. This degree of polymerization of SF HA was significantly (P < 0.01) lower, compared with that for control joints. There was no difference in mean (+/- SD) concentration of HA between control joints and joints with acute or chronic traumatic arthritis (0.33 +/- 0.12 g/L vs 0.18 +/- 0.03 g/L or 0.23 +/- 0.12 g/L), indicating that SF HA concentration probably should not be used as a diagnostic marker for the condition.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1993

The effect of intermaxillary fixation on leukocyte zinc, serum trace elements and nutritional status of patients undergoing maxillofacial surgery.

Mononuclear cell (MNC), polymorphonuclear cell (PMNC) and serum zinc levels were studied in 17 oral surgical patients with intermaxillary fixation. Serum copper, iron, selenium and bromide concentrations were also measured together with common indices of nutritional status. Nine patients received nutritional counselling. Eight patients had, in addition, oral supplementation with a commercial formula. No changes in intracellular or serum zinc levels were seen during the study period. A statistically significant decrease was seen in mean body weight with subsequent changes in anthropometry. Maximal mean weight loss was 6.0 +/- 3.8% in control group and 3.8 +/- 2.7% in supplemental group. The impaired oral intake due to intermaxillary fixation does not interfere significantly with zinc status as estimated by MNC, PMNC or serum zinc levels. The reduction in body weight and anthropometric indices in the relatively short fixation period may be clinically significant in some patients. Supplementation with a commercial formula helps to maintain the nutritional status of these patients.

Journal Article↗
PubMed1993

Enalapril premedication attenuates the blood pressure response to tracheal intubation and stabilizes postoperative blood pressure after controlled hypotension with sodium nitroprusside in neurovascular patients.

Oral premedication with enalapril, 0.1 mg/kg was compared with placebo in 22 patients subjected to craniotomy and ligation of an intracranial aneurysm or extirpation of an arteriovenous malformation. Balanced hypotensive anesthesia was used with sodium nitroprusside (SNP) as the main hypotensive agent. The hypertensive response to laryngoscopy and tracheal intubation was significantly attenuated by enalapril (p = 0.020). The mean blood pressure was lower and more stable in the intensive care unit after enalapril than after placebo (p = 0.044). The median SNP dose rate tended to be lower in the enalapril-pretreated patients [0.6 (range of 0-3.5) micrograms/kg/min] compared to the placebo group [1.4 (0.4-5.8) micrograms/kg/min] (p = 0.12). Concentrations of plasma catecholamines, vasopressin, and endothelin as well as serum osmolality, arterial blood gases, and plasma electrolytes and level of consciousness were repeatedly measured. Enalapril had no significant effects on these variables. Plasma renin activity was increased and serum angiotensin converting enzyme (ACE) activity was reduced in the expected manner by enalapril. We found premedication with an ACE inhibitor favorable for hypotensive anesthesia in neurovascular patients as assessed by the circulatory responses.

Administration, Oral↗
PubMed1993

Implementation of a radioreceptor assay for dexmedetomidine.

We have implemented a radioreceptor assay for dexmedetomidine, a novel alpha 2-adrenoceptor agonist. Receptor-bearing membranes were prepared from rat cerebral cortex and 3H-clonidine, 4 nM, was used as the labeled ligand. Dexmedetomidine displaced 3H-clonidine in a linear fashion over a concentration of 2 x 10(-10) to 2 x 10(-8)M. The detection limit of dexmedetomidine (i.e. 10% of radiolabeled ligand displaced) in this assay was 50 pg.ml-1 which is comparable to that seen with the reference method which utilizes gas chromotography with mass spectrometer (GC/MS) in series (Vuorilehto et al. 1989). Endogenous catecholamines, which can displace the radiolabeled ligand from its binding site, could easily be eliminated with a one-step extraction procedure. A comparison was made with the reference method (GC/MS) in 47 human plasma samples; the correlation coefficient (r2) was 0.61 (P < 0.001). The radioreceptor assay was also successfully applied for determining dexmedetomidine concentration in rabbit samples. These data indicate that the radioreceptor assay can be utilized for characterizing the pharmacokinetics of novel alpha 2 agonists which are now being introduced into the clinical practice of anaesthesia.

Adrenergic alpha-Agonists↗
PubMed1992

Dexmedetomidine synergism with midazolam in the elevated plus-maze test in rats.

The anxiolytic profile of dexmedetomidine, a novel, highly-selective alpha 2-adrenergic agonist, was examined in rats in the elevated plus-maze test when administered either alone or in combination with the benzodiazepine agonist midazolam. Dexmedetomidine, 0.1-10 micrograms/kg, was inactive in modifying the rats' behavioral response in this test. Midazolam, 0.1-10 mg/kg, dose-dependently produced an anxiolytic-like profile characterized by an increased time spent in the open arms of the elevated plus-maze. A combination of dexmedetomidine 0.5 micrograms/kg and midazolam 0.5 mg/kg produced a synergistic interaction. This heterergic interaction of dexmedetomidine on midazolam's anxiolytic-like profile was dose-dependently blocked by pretreatment with an alpha 2-adrenergic antagonist, atipamezole, 10-50 micrograms/kg, and a benzodiazepine antagonist flumazenil, 1.0 and 10 mg/kg, but not by the alpha 1-adrenergic antagonist, prazosin, 0.1-10 mg/kg. While the transmembrane signal transduction pathways for benzodiazepine- and alpha 2-agonist responses do not share any molecular component, there does appear to be "crosstalk" between these two systems. These may involve GABA or noradrenergic "downstream" effects of either dexmedetomidine or midazolam, respectively.

Adrenergic alpha-Antagonists↗
PubMed1992

Successful pain management by Finnish oral surgeons. A clinical follow-up study.

The current practice of postoperative pain management among Finnish oral surgeons was evaluated in a two-phase study. In the first phase, a questionnaire was sent to specialist members of the Finnish Society of Oral and Maxillofacial Surgeons that concerned the routine use of analgesic drugs after surgical removal of third molar teeth. In the second phase, the clinical adequacy of pain medication was assessed in 84 patients who had the same procedure. Patients estimated the intensity of pain with a 100 mm visual analogue scale at five time points during the day of surgery and on three postoperative days. Anti-inflammatory analgesics were widely used either alone or in combination with centrally acting analgesic drugs. Tolfenamic acid, diclofenac, and ketoprofen were the most commonly used analgesic drugs. The analgesic effect of the currently used drug combinations proved to be sufficient except in a few patients during the first night after surgery.

Adult↗