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Biomedical subjects

H Savolainen

Publications and source records attributed to H Savolainen.

At least 73 records · Page 4Linked to original sources
PubMed1992

Healing of bladder wall after contact and non-contact Nd-YAG laser photocoagulation. Experimental study in piglets.

The healing process of the bladder wall after contact and non-contact Nd-YAG laser irradiation was studied in 18 piglets. The animals were sacrificed 1 h, and 2, 5 and 14 days after photocoagulation. The lesions were examined histologically by light and scanning electron microscopy. Immunohistochemical stains were prepared for visualization of lactate dehydrogenase. Perforation of the bladder wall was found in 2 cases where a contact probe was used (15 W/2 s). A crater in the bladder wall resulting from tissue ablation was seen in all cases immediately after contact laser irradiation. Photocoagulation using a non-contact laser led to white necrosis in the bladder wall. Minimal tissue ablation was evident at the highest power setting used (35 W/2 s). After 2 days inflammation around the lesion was marked. Inflammation with fibroblasts invading the damaged area was seen 5 days after photocoagulation. Fourteen days after photocoagulation minor scar formation was evident beneath the histologically normal epithelium. It is concluded that lesions caused by contact or non-contact Nd-YAG laser photocoagulation will heal within 2 weeks with minor scar formation.

Animals↗
PubMed1992

A sensitive method for the analysis of urinary proteoglycans.

Twelve control persons excreted 282 +/- 106 micrograms proteoglycans/l urine (+/- S.D.) in a random urine sample. For four patients with a clinical proteinuria of 1.1 to 5.8 g/l, the excretion varied between 52 and 387 micrograms/l. The control proteoglycan pattern in an electrophoretic analysis on polyacrylamide gel and stained with digoxigenin followed by incubation with digoxigenin antibodies, consisted of a major band with a molecular weight of 100,000. It comigrated with a similar band in the serum proteoglycan pattern. The control pattern contained also lighter fractions with molecular weights between 50,000 and 28,000. The major proteoglycan band remained unchanged in the pattern of the proteinuric patients while conspicuous new bands appeared in the pattern of patients with proteinuria greater than 1.9 g/l. They seem to be of urinary tract origin as they had no counterparts in the serum proteoglycan pattern.

Blotting, Western↗
PubMed1992

Peripheral excimer laser-assisted angioplasty. Preliminary clinical experience.

A non-thermal Xenon-Chloride excimer laser was used for peripheral arterial recanalization in eight patients with obliterating atherosclerosis of the superficial femoral artery. All patients had a total occlusion with severe claudication or pain at rest. There were three complications, which all led to thrombosis of the irradiated artery. In one, the puncture site in the artery had to be closed operatively. All vessels were followed up radiographically three months after the procedure. In seven patients the vessel was patent. Several investigators have warranted caution in using thermal lasers (continuous wave Nd:YAG or argon) for angioplasty. The non-thermal excimer laser is a viable alternative--although not without problems. Initial experiences with the new device are described.

Aged↗
PubMed1992

A simple method for detecting protein antigens in flour.

Wheat, barley, rye or oat flour was dissolved in 0.2N NaOH using magnetic stirring followed by sonication. The ensuing clear solutions contained 95% of protein in the dry matter. Aliquots were electrophoresed on 12% polyacrylamide gels which were either stained with Coomassie brilliant blue or Western-blotted on nitrocellulose membrane. Incubation of the latter with serum from persons sensitized to flours allowed the detection of antigenic flour protein classes. It seems that many antigens are present in common kitchen flour.

Allergens↗
PubMed1991

Bicarbonate-catalyzed hydrolysis of hexamethylene diisocyanate to 1,6-diaminohexane.

The hydrolysis of hexamethylene diisocyanate (HDI) in water was tested in a dynamic and stationary system. Without catalysts, the reaction was very slow (less than 1% in 10 min at 30 degrees C) while the addition of simple carboxylic-acid-containing neutral buffers markedly catalyses the formation of 1,6-diaminohexane as the known hydrolysis product. The catalytic efficiency of formic acid, oxalic acid, acetic acid, lactic acid, citric acid and carbonic acid increased in this order while phosphate, glycine and glutamate were inactive even at very high concentrations. A 20 mM bicarbonate buffer was the optimal catalyst, but below this concentration the rate of HDI hydrolysis was drastically reduced. It is suggested that the hydrolysis of inhaled HDI in the lungs may be catalysed by bicarbonate in the blood, giving rise to amines found as urinary metabolites following occupational exposure.

Bicarbonates↗
PubMed1991

Determination of 4-methyl-cis-hexahydrophthalic anhydride in human blood by gas chromatography with electron-capture detection.

A gas-chromatographic technique using 63Ni electron-capture detection was applied to the determination of 4-methyl-cis-hexahydrophthalic anhydride in the blood of workers occupationally exposed to this airborne agent. The detection limit was 0.24 nmol ml-1. For occupational exposure to between 0.14 and 0.31 mg m-3 of the anhydride, the anhydride concentration in the workers' blood samples ranged from 3.4 to 10.7 nmol ml-1. The results are consistent with earlier findings in animal exposure experiments and support the view that the hydrolysis of the anhydride in a biological medium is not spontaneous, but might be an enzyme-catalysed reaction. The resulting dicarboxylic acid is excreted by the kidneys without further conjugation reactions.

Air Pollutants, Occupational↗
PubMed1991

Methanol and formic acid toxicity: biochemical mechanisms.

Metabolism of methanol, methyl ethers, esters and amides give rise to formic acid. This acid is an inhibitor of the mitochondrial cytochrome oxidase causing histotoxic hypoxia. Formic acid is a weaker inhibitor than cyanide and hydrosulphide anions. The body burden of formate in methanol poisoning is high enough to cause acidosis, and other clinical symptoms. Part of the protons can be attributed to formic acid whereas the most significant acid load results from the hypoxic metabolism. The acidosis causes e.g. dilatation of cerebral vessels, facilitation of the entry of calcium ions into cells, loss of lysosomal latency and deranged production of ATP. The latter effect seems to impede parathormone-dependent calcium reabsorption in the kidney tubules. Besides, urinary acidification is affected by formic acid. Its excretion causes continuous recycling of the acid by the tubular cell Cl-/formate exchanger. This sequence of events may partially explain an accumulation of formate in urine. Occupational exposure to vapours of methanol and formic acid can be quantitatively monitored by urinary formic acid determinations. Formic acid toxicity may prove a suitable model for agents causing histotoxic hypoxia.

Acidosis↗
PubMed1991

Nd: YAG contact laser in partial nephrectomy. An experimental study in piglets.

The Nd: YAG contact laser technique with 12 W power output was used in partial nephrectomies in six piglets. Blood loss, total time and number of ligatures needed for haemostasis were compared in six partial nephrectomies performed with a steel scalpel. Mean blood loss was 53 g with the laser and 108 g with the steel scalpel (p less than 0.04). The mean time needed for haemostasis were 9.5 and 16.2 min respectively (p = 0.2) and the average number of ligatures required 1.5 and 8.8, respectively. The mean temperature rise at 5, 10 and 20 mm distance from the resection line was 5.3, 1.2 and 0.3 degrees C, respectively. The use of laser reduced blood loss and shortened the operation time. Further studies are needed concerning renal function after kidney surgery with a laser.

Animals↗
PubMed1991

Antitrypsin phenotypes in occupational organic diisocyanate asthma.

Eleven subjects with clinical bronchial hyperreactivity towards hexamethylene diisocyanate used in their work and verified by spirometry before and after a shift were screened for their antitrypsin phenotypes by isoelectric focusing. One third were M1M1 homozygotes (over 50% in controls) while the rest were heterozygotes comprising one case, each, of M1S and M1I (expected frequencies 5 and 0.5%, respectively). It seems that heterozygous alpha 1-antitrypsin carriers may be at a greater risk to develop a pulmonary disease in the organic diisocyanate exposure than the homozygotes.

Asthma↗
PubMed1990

Urinary arginine and ornithine in occupational exposure to 2-ethylhexanoic acid.

Nine sawmill workers were divided into two groups according to their exposure to 2-ethylhexanoic acid, (EHA), a pesticide which has replaced the older pentochlorophenol. The men with lower exposure excreted 30 +/- 10 nmol EHA/mmol creatinine (mean +/- SD, n = 4) in urine samples taken after the workshift, whereas men with higher exposure excreted 1.8 +/- 1.6 mumol EHA/mmol creatinine (mean +/- SD, n = 5, p less than 0.01). The urinary ornithine and arginine concentrations were at the lower exposure 1.4 +/- 0.4 and 1.5 +/- 0.8 mumol/mmol creatinine, respectively (mean +/- SD, n = 4), and they increased significantly (p less than 0.01) to 4.5 +/- 2.5 and 3.2 +/- 1.5 mumol/mmol (mean +/- SD, n = 5), respectively, at the higher exposure. This might have been caused by the inhibitory effect of EHA on urea synthesis which was partially compensated for by elevated arginine and ornithine concentrations to drive the urea cycle more efficiently.

Adult↗
PubMed1990

Demethylation pathways in caffeine metabolism as indicators of variability in 1,1,1-trichloroethane oxidation in man.

Twenty volunteers were exposed to 191 +/- 7 p.p.m. 1,1,1-trichloroethane or 50 +/- 2 p.p.m. perchloroethylene vapour for 6 hr. They were then evaluated for their rate of caffeine metabolism, mephenytoin hydroxylation and debrisoquine hydroxylation. Seven subjects were identified as 'fast acetylators' of caffeine and one person as a slow metabolizer of debrisoquine. The "slow acetylators" exposed to perchloroethylene excreted an average of 3.83 +/- 0.35 mg trichloroacetic acid within 24 hr (N = 13, +/- S.E.) and the 'fast acetylators' 3.58 +/- 0.48 mg (N = 7, +/- S.E.). The excretion of trichloroethanol by the same persons after 1,1,1-trichloroethane exposure was 14.1 +/- 1.12 mg and 16.7 +/- 1.48 mg, respectively. The excretion of trichloroacetic acid in the latter exposure varied significantly between the seven 'fast' and 13 'slow acetylators' (0.43 +/- 0.08 mg versus 1.03 +/- 0.19 mg; +/- S.E.; P = 0.037). A multiple linear regression analysis confirmed this association when other factors, such as body weight, creatinine clearance, smoking habit and alcohol consumption, were taken into account. One volunteer proved to be a poor hydroxylator of debrisoquine and excreted half the amount of trichloroacetic acid in the perchloroethylene exposure and half the amount of trichloroethanol in the 1,1,1-trichloroethane exposure compared to the others. A reduction in the solvent metabolism could thus be predicted by the debrisoquine test. On the other hand, the caffeine test predicted faster oxidation of trichloroethanol which could be of toxicological and pharmacological importance e.g. in the clinical use of chloral.

Adult↗
PubMed1990

Laser for harvesting of the internal mammary artery.

In 12 piglets both internal mammary arteries were dissected from the thoracic wall without a surrounding pedicle, using low-current electrocautery for one artery and continuous wave contact Nd:YAG laser (12 W) for the contralateral vessel. Changes in the arterial flow surface were evaluated by scanning electron microscopy immediately after dissection and 2 and 5 days postoperatively. Laser dissection was easier, more accurate and as fast as electrocautery. Moderate to severe degenerative changes and endothelial desquamation were seen in the electrocautery group after dissection, but lesser changes in the laser group. The changes decreased within the next 5 days, but two electrocauterized vessels showed thrombosis at 5 days. Stripping of the internal mammary artery with either method requires great care, and Nd:YAG laser offers a promising alternative to electrocautery in harvesting of that artery as a pedicled graft.

Animals↗
PubMed1990

The healing of contact Nd:YAG laser irradiated arterial wall. An experimental study in piglets.

The healing of an arterial lesion created by continuous wave contact Nd:YAG laser was investigated. Normal arterial walls were irradiated. It is nearly impossible to irradiate atheromatous plaques without involving adjacent normal arterial wall as well. The purpose of this study was to evaluate the healing process using a standard thermal laser. Different power outputs were used with 1.0 sec exposure. A cw Nd:YAG laser with a wavelength of 1064 nm was used. Eighteen piglets underwent laparotomy. An 0.6 mm fibre with a rounded 2.2 mm sapphire probe was introduced into the aorta and iliac arteries. The irradiation was performed vertically to the vessel wall. The artery specimens were studied histologically and through electron scanning microscopy. Immediately after irradiation, adherence of platelets was observed. At two days the core centre was invaded with mononuclear blood cells and polymorphonuclear leukocytes. At five days there was still some denudation of endothelium, and the initial debris started to disappear. At two weeks medial smooth muscle cells were seen around the necrotic zone. The area was encapsulated by layers of smooth muscle and collagen. The healing process seems similar to that of mechanical injury of the aortic intima.

Angioplasty, Balloon↗
PubMed1990

Isoelectric focusing of urinary metallothionein.

Isoelectric focusing of human urinary metallothionein at a pH range of 4.8 to 7.0 yielded a single protein band with a pI of 5.57 which co-migrated with authentic purified metallothionein I from human liver. Minimum pretreatment of the urine samples (160 ml) was needed. The preparatory steps included sample concentration with the original protein, enriched from 69 +/- 23 micrograms/ml to 2.0 +/- 1.4 mg/ml (+/- SD; n = 9), followed by heat treatment at 80 degrees C for 5 min (2.4 +/- 1.7 mg protein/ml). After focusing, the gels were stained with silver and the lanes were scanned with a laser scanner. Peak areas were used for quantitation with commercial beta 2-microglobulin as a standard. The urinary metallothionein ranged from 1.0 to 2.6 nmol/mmol creatinine, which is comparable with values reached by radio-immunoassay.

Hot Temperature↗
PubMed1990

The effect of contact Nd:YAG laser on arterial wall and atherosclerotic plaques. Considerations for angioplasty. An experimental study.

The predictability and reproducibility of the laser effect in regard to depth of penetration and atheroablation are important considerations for clinical laser angioplasty. This study was designed to investigate those effects experimentally. A continuous wave contact laser system (SLT CL60R with an SLT MTR 1.5 sapphire tip) was used to produce a total of 592 lesions on 14 portions of atherosclerotic human aorta and 46 portions of intact pig aorta. Different power (1 to 40W) and time (0.1 to 10 sec.) were used. These tissue specimens were analyzed by an independent pathologist. Penetration and extent of thermal damage were recorded. The measurements were analyzed statistically. Analysis shows that the effect of the laser is reasonably well predictable horizontally (correlations .755 and .699) but not at all in depth (correlation .006).

Animals↗