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Biomedical subjects

K Savolainen

Publications and source records attributed to K Savolainen.

At least 55 records · Page 3Linked to original sources
PubMed1993

Acute effects of m-xylene inhalation on body sway, reaction times, and sleep in man.

Nine male volunteers were exposed to either a constant or a fluctuating exposure pattern of m-xylene with a time-weighted average exposure concentration of 200 ppm in both cases. The subjects remained sedentary throughout the exposure, or the exercised at 100 W for 10 min at the beginning of the morning and the afternoon sessions. In another experiment, 12 sedentary male volunteers were exposed to a fixed 200 ppm of m-xylene. The effects of m-xylene on body sway, reaction time performance, and overnight sleep were measured. Body balance was stabilized after exposure to the peaks of 400 ppm of m-xylene in both sedentary and exercising subjects. Simple visual reaction times were prolonged after the peak exposures at rest whereas auditive choice reaction times were prolonged after peaks combined with exercise. Exposure to m-xylene at a constant level of 200 ppm did not affect the ratio of "active" to "quiet" sleep in the volunteers as measured with the static charge sensitive bed recording, but decreased slightly the number of body movements in bed. On the next morning no changes were found in body sway and reaction time performance as compared to the morning before exposure.

Adult↗
PubMed1993

Carbachol- and KCl-induced changes in phosphoinositide metabolism and free calcium in guinea pig cerebral cortex synaptosomes.

Phosphoinositide (PI) and calcium metabolism were studied in guinea pig cerebral cortex synaptosomes. Mass amounts of inositol and inositol monophosphates, and the levels of free intrasynaptosomal calcium ([Ca2+]i) were measured after KCl (60 mM), after a direct cholinergic agonist carbachol (CA, 1mM), and after their combination. Inositol, inositol-1-phosphate (Ins1P), inositol-4-phosphate (Ins4P) and [Ca2+]i were measured with and without 10 mM LiCl in the incubation medium. CA-induced cholinergic stimulation elevated synaptosomal Ins4P levels by 40% but did not affect Ins1P or [Ca2+]i. On the contrary, KCl elevated Ins1P by 50% and [Ca2+]i by 40% above the resting level, and decreased inositol by 20%, whereas no alterations in Ins4P occurred. CA did not modify the responses of KCl, but KCl abolished the elevation of Ins4P by CA. LiCl attenuated KCl-induced elevation of Ins1P but amplified the CA-induced elevation of Ins4P. The elevation of presynaptic [Ca2+]i was accompanied by accumulation of Ins1P but not that of Ins4P. Hence, the present results suggest that presynaptic cholinergic stimulation and KCl-induced depolarization may activate different degradation pathways of inositolphosphate metabolism.

Animals↗
PubMed1993

Exposure of sprayers and plant handlers to mevinphos in Finnish greenhouses.

The exposure of sprayers and plant handlers to mevinphos, a toxic organophosphate insecticide, was evaluated in eight flower-growing greenhouses. The purpose was to assess an appropriate re-entry interval for mevinphos after its application in greenhouses. Inhalational and dermal exposure was measured during two days after application by measuring mevinphos in the greenhouse air and on the foliage. Workers' dermal exposure was measured with patch and handwash samples. The method of application considerably affected the levels of mevinphos in greenhouse air and on the foliage. The occupational exposure was measured with patch and handwash samples. The method of application considerably affected the levels of mevinphos in greenhouse air and on the foliage. The occupational exposure limit for mevinphos in Finland (100 micrograms/m3) was exceeded during the use of nonthermal foggers. Usually, however, the concentration of mevinphos in the breathing zone of the workers was below 10 micrograms/m3 9-12 hr after application. Mevinphos disappeared rapidly from greenhouse air and from the foliage after application, with a half-life of 9.2 hr. These data provide evidence that the main route of exposure to mevinphos is dermal, a conclusion supported by the excellent correlation between dermal exposure and the amount of mevinphos on the foliage. The calculated re-entry interval for mevinphos was approximately 4.5 hr. However, that interval is likely to be too short in practice because the risk of dermal exposure is considerable for more than 10 hr after the application of mevinphos.

Adult↗
PubMed1993

Quality specifications for S-AFP and S-HCG-beta determinations for screening of fetal abnormalities.

High levels of maternal serum alpha-1-fetoprotein (S-AFP) are associated with fetal structural abnormalities like neutral tube defects and congenital nephrosis. It has a very high detection rate when used for screening of these diseases. On the other hand, the low levels of maternal S-AFP act as a marker of many fetal chromosomal aberrations. The detection rate of S-AFP alone for the screening of Down's syndrome is low. Wald et al. have shown that the addition of the determination of maternal serum chorionic gonadotrophin (S-HCG-beta) to S-AFP analysis, and using a computer program for risk estimation increases the detection rate for Down's syndrome to about 57% with a false positive rate of 5%. In this study we present the results of our screening program for structural fetal defects and chromosomal aberrations in Eastern Finland, and describe the standardization and quality control of maternal serum AFP and HCG-beta analysis.

Adult↗
PubMed1991

Lithium-induced decrease of brain inositol and increase of brain inositol-1-phosphate is transient.

The effects of a single dose of LiCl (2.5 or 10 mEq/kg) on brain inositol and inositol-1-phosphate (Ins1P), intermediates of brain phosphoinositide (PI) turnover, were determined in male Han: Wistar rats. There was a remarkable, 36-58 fold elevation of brain Li+ as the single dose of LiCl was increased 4-fold. Moreover, the accumulation of brain lithium was slow during repeated administration of LiCl. Brain lithium did not correlate with changes in brain PI turnover either after a single or repeated doses. Thus, after a single dose of LiCl the increases in brain Ins1P were much less than the decreases in brain inositol. Also, brain inositol was significantly decreased only with the high dose of LiCl whereas brain Ins1P accumulation was more prominent with the lower dose. Moreover, repeated daily doses of LiCl only transiently increased brain Ins1P at 1 and 7 d whereas inositol remained at control levels throughout the 14 d observation period. Lithium probably caused the transient decrease in brain inositol by inhibiting several enzymes, in addition to the inhibition of myo-inositol mono-phosphates, in the PI cycle. Moreover, a slow dampening down of PI turnover by lithium, possible via an inhibitory action on G-protein-coupling, may also explain the present findings.

Analysis of Variance↗
PubMed1991

Urinary excretion of ethylenethiourea and kidney morphology in rats after continuous oral exposure to nabam or ethylenethiourea.

Nabam, an ethylenebisdithiocarbamate (EBDC), is an agricultural fungicide. Ethylenethiourea (ETU), widely used in the rubber industry, is a degradation and byproduct of metabolism and of storage and production of EBDCs. Kidney function and morphology, and urinary excretion of ETU, were studied in rats exposed to nabam or ETU in drinking water for 28 days. The concentrations of nabam in drinking water were 0, 50, 100 or 200 mg/l, and of ETU 0, 100, 200 or 300 mg/l. Both compounds decreased body weight gain but did not significantly affect urinary sodium, potassium, glucose, or protein excretion, or urinary osmolality. Urinary vasopressin was also unaltered after exposure to nabam or ETU. High doses of ETU resulted in ultrastructural alterations in epithelial cells of renal proximal tubuli. ETU was excreted in urine after exposure to both nabam and ETU. There seemed to be a threshold dose of ETU below which no ultrastructural alterations in kidney occurred.

Administration, Oral↗
PubMed1990

Problems with the use of whole blood as a sample material in novel direct glucose analysers.

We report a marked shift in whole-blood glucose measurements when a widely available glucose analyser is used. We compared a conventional glucose dehydrogenase (GDHG) method after protein precipitation and a direct polarographic method in conjunction with immobilized glucose oxidase. The polarographic method gave mean whole blood glucose levels from 79% to 95% of those measured by the GDHG method. No such difference was found in either plasma or serum samples or in water-based control samples. The stability of glucose in fluoride oxalate tubes appears to be poorer than is usually assumed. We observed a 5-10% decrease in whole-blood glucose concentrations during the first hour after sampling under routine conditions.

Blood Glucose↗
PubMed1990

Environmental and biological monitoring of exposure to ethylenebisdithiocarbamate fungicides and ethylenethiourea.

Exposure of workers to ethylenebisdithiocarbamates (EBDCs; maneb or mancozeb) in 29 potato farms was evaluated during the control of potato late blight. Concentrations of EBDCs and ethylenethiourea (ETU), an impurity and degradation product in EBDC formulations, in ambient air were evaluated during pesticide application. Biological monitoring of exposure to EBDCs was carried out by measuring the concentrations of ETU, a metabolite of EBDCs, in urine for 22 days after the end of the exposure. The estimated inhaled doses of ETU and EBDCs during the average four hour application period were 0.07 and 1.8 micrograms/kg, respectively. Only 1-10% of ETU on the clothes reached the skin. The creatinine corrected concentrations of ETU in urine were 0.1-2.5 micrograms/mmol creatinine 24 hours after exposure ended. The estimated half life for eliminating ETU through the kidneys was close to 100 hours. These results indicate that the measurement of ETU in urine is suitable for biological monitoring of exposure to EBDCs.

Agriculture↗
PubMed1990

Ethylenethiourea in air and in urine as an indicator of exposure to ethylenebisdithiocarbamate fungicides.

Ethylenethiourea (ETU) is a ubiquitous impurity of the ethylenebisdithiocarbamate (EBDC) fungicides widely used in agriculture and forestry. In the present study, ETU was used as a measure of the exposure to EBDC on potato farms and in pine nurseries during the application of EBDC fungicides and the weeding of the sprayed vegetation. Biological and hygienic monitoring was carried out through the analysis of ETU in the breathing zone and the urine of exposed workers. Even if the concentrations of ETU in the ambient air of pine nurseries exceeded those of potato farms, the concentrations of ETU in the urine of potato farmers exceeded those of pine nursery workers. This result may have been due better protective equipment in the pine nurseries. The excretion rate was 6-10 ng/h during the first 60 h after the cessation of exposure, and it diminished thereafter to 0.2 ng/h over a 22-d observation period.

Adult↗
PubMed1989

Time-course of malaoxon-induced alterations in brain regional inositol-1-phosphate levels in convulsing and nonconvulsing rats.

The potential of a single dose of malaoxon (26.2 or 39.2 mg/kg i.p.) to produce convulsions and to increase cerebral levels of inositol-1-phosphate (Ins1P), an intermediate in phosphoinositide (PI) cycle, was followed for 1, 4, or 72 hr. The lower dose of malaoxon did not produce convulsions whereas the higher dose induced convulsions in 60% of the exposed rats. Malaoxon caused a dose-dependent, at most 2-fold, increase in brain regional Ins1P levels in nonconvulsing rats as compared to controls. At the higher dose of malaoxon, in convulsing rats, the Ins1P-levels increased 4-fold above the control Ins1P-levels. In nonconvulsing rats, the Ins1P-levels reached their maximum 1-4 hr after the administration of malaoxon, whereas in convulsing rats the levels increased for 72 hr. The results suggest that PI-signalling is associated with convulsions produced by malaoxon.

Animals↗
PubMed1989

Metabolic and nutritional effects of long-term use of guar gum in the treatment of noninsulin-dependent diabetes of poor metabolic control.

Thirty-nine patients with noninsulin-dependent diabetes on oral drug treatment were randomly allocated to either guar gum or placebo treatments for 3 mo. After 3 mo the placebo group was switched to guar gum treatment and both groups were followed for 10 mo (open trial). No significant difference occurred in the fasting blood glucose or glycosylated hemoglobin A1 levels between the two groups at 3 mo. Serum total cholesterol level decreased in the guar gum group from 6.55 +/- 1.45 to 5.69 +/- 1.2 mmol/L (p less than 0.001) but no changes were observed in the placebo group (6.55 +/- 1.2 vs 6.26 +/- 1.4 mmol/L, NS) during 3 mo. At the end of the open trial (n = 33), serum cholesterol was still approximately 7% lower than before guar gum treatment. No consistent changes occurred in serum HDL-cholesterol or triglycerides. Serum vitamin A level was slightly lowered and plasma zinc level elevated during the open trial. Serum vitamin E level was decreased only in the group switched to guar gum at 3 mo.

Adult↗
PubMed1988

A gas chromatographic method for the determination of inositol monophosphates in rat brain.

Regional levels of cerebral inositol-1-phosphate (Ins1P), an intermediate in phosphoinositide (PI) cycle, were readily detected with a new gas chromatographic (GC) method. GC analysis of trimethylsilyated Ins1P and myo-inositol-2-phosphate with a fused silica capillary SE-30 column and flame ionization detection was linear at picomolar range (pmol/microliter) with a sensitivity to a level of 2 pmol. Also, inositol monophosphates and glucose-6-phosphate are separated in unstimulated brain tissue. The mean recovery of the method is 98 +/- 5.2%. Ins1P levels were higher in frontal than in caudal regions in control brains. Lithium treatment increased the levels of Ins1P throughout the brain but mostly in frontal brain regions and in the hippocampus. The present GC assay to measure the accumulation of Ins1P, an index for the activity of PI signaling, may be suitable for exploring regional differences in cerebral receptor-coupled PI signalling in vivo.

Animals↗
PubMed1988

Pharmacokinetic comparison of a slow-release theophylline-hydroxyzine combination and a plain slow-release theophylline preparation.

We have compared the pharmacokinetic properties of a slow-release theophylline-hydroxyzine combination and a slow-release theophylline preparation both after a single dose administration and at steady state after the dosage of twice/day for four days in ten healthy volunteers. After a single dose, theophylline was absorbed slightly faster from the combination preparation (Retafyllin comp.) than from a plain theophylline preparation (Theo-Dur). However, in a steady state phase the pharmacokinetic profiles were quite similar. Hydroxyzine showed a slight delay in absorption from the combination preparation, but in a steady state the overall pharmacokinetic profile of hydroxyzine was similar to that of theophylline. Cumulation of either hydroxyzine or theophylline was not evident. On the basis of the present study, the slow-release combination preparation of theophylline and hydroxyzine seems suitable for twice/day dosage.

Adult↗