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Biomedical subjects

M Leskinen

Publications and source records attributed to M Leskinen.

12 recordsLinked to original sources
PubMed2001

Mast cell chymase induces apoptosis of vascular smooth muscle cells.

In human coronary atheromas, the numbers of degranulated mast cells and of apoptotic smooth muscle cells (SMCs) are increased. Accordingly, the possibility exists that mast cells participate in the regulation of SMC apoptosis in the lesions. Mast cells isolated from the serosal cavities of rats were stimulated to release their secretory granules. The neutral protease chymase, present in the exocytosed granules, was found to induce apoptosis when added to rat aortic SMCs in culture. The chymase-induced apoptosis of SMCs was detected by flow cytometry, microscopic analysis of cellular morphology, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL), and electrophoretic demonstration of DNA laddering. Chymase induced SMC apoptosis in a dose- and time- dependent manner, and its proteolytic activity was essential for the proapoptotic effect. In addition to rat chymase, recombinant human chymase was also found to induce apoptosis of human coronary artery SMCs in culture. These results suggest that mast cells may participate in the apoptotic regulation of SMCs in atherosclerotic lesions.

Animals↗
PubMed2000

Doppler radar detection of exceptional mass-migration of aphids into Finland.

Our objective was to detect mass migrations of insects of economic significance by insect traps and a Doppler weather radar. Migrants were sampled by suction traps, tow nets and light traps in the Helsinki region. We used radar to observe the migrating insects, and trajectories to backtrack mass migrations of aphids (Homoptera, Aphididae) in spring 1988. The aphid migrations were clearly observed in trap catches and by radar. The first migration, mainly involving Euceraphis betulae, occurred on 18 May and was tracked back to northern Poland. The second migration, mainly of Rhopalosiphum padi (a serious pest of small-grain cereals), occurred 3 days later and was tracked back to a large area covering Latvia and western Russia south of St Petersburg. The third migration included both E. betulae and R. padi, and took place on 30 May. It originated from Estonia. Neither trap nor radar data provide exact quantitative information on migrations. Trapping efficiency depends strongly on wind speed and insect size. Radar echo intensity is very strongly related to the sizes of insects in the large volume of air measured, and the sizes are not known accurately. Weather data, especially temperature, can be used in predicting the development of aphids, and air-parcel trajectories in estimating the source areas of migrants. These methods for forecasting aphid migrations, combined with radar observations, are useful for warning purposes and to intensify insect trapping. This would contribute to more efficient agricultural pest management.

Agriculture↗
PubMed1999

Effects of finasteride in patients with inflammatory chronic pelvic pain syndrome: a double-blind, placebo-controlled, pilot study.

OBJECTIVES: To investigate whether treatment of inflammatory chronic pelvic pain syndrome (ICPPS) with finasteride has any influence on symptoms associated with ICPPS. METHODS: Forty-one patients with ICPPS were randomized (1:3) to treatment with either placebo (25%, n = 10) or finasteride 5 mg daily (75%, n = 31 ) for 1 2 months. Efficacy was evaluated by analysis of symptomatic improvement through responses to symptom questionnaires, pain evaluation on an analytical visual scale, analgesic use as reported in patient diaries, urine flow and residual volume, and prostate volume. RESULTS: Prostatitis Symptom Severity Index and prostatism scores dropped significantly in patients in the finasteride group (P < 0.001 and P < 0.05, respectively). There were no statistically significant differences in pain between the groups. There were significant differences in the changes of prostate volume and in serum prostate-specific antigen concentrations between the finasteride and placebo groups (P < 0.03 and P < 0.02, respectively). The groups did not differ with regard to side effects. CONCLUSIONS: Our results indicate that finasteride has an effect in ICPPS. The mechanisms by which finasteride works in these patients are unclear and could not be solved in this pilot study, which had relatively few patients. A further trial with larger numbers is required to confirm these results.

Adult↗
PubMed1997

Effects of surface-induced hypothermia and rewarming on canine cardiac contraction-relaxation cycle.

The aims of this study were to elucidate the effects of cooling and rewarming on cardiac contraction-relaxation cycle. Cardiac catheterization was carried out on eleven anaesthetized beagle dogs. The dogs were cooled between icebags until the temperature of the blood in the ascending aorta was 25 degrees C and then rewarmed. Heart rate increased transiently at the beginning of cooling down to 33 degrees C (P < 0.05). Cardiac output first tended to increase until a body temperature of 33 degrees C was achieved but then decreased (P < 0.05). The systolic period lengthened significantly (P < 0.001) when the body temperature decreased from 37 degrees C to 25 degrees C. Cardiac relaxation slowed down linearly with temperature during cooling. The peak value of the first order derivative of the ventricular pressure curve (dP/dtmax) increased at the beginning of cooling down to 33 degrees C, indicating enhanced systolic pressure rise in left ventricle but returned to baseline values at lower temperatures. However the ejection fraction, systolic period and the systemic vascular resistance increased at the temperatures below 33 degrees C despite the unaltered peak dP/dt and thus we conclude that the contraction force is augmented in the hypothermia. All the parameters measured recovered to normal during rewarming and no signs of heart failure were noted during the experiments.

Animals↗
PubMed1992

Reversibility of hypertensive vascular changes after coarctation repair in dogs.

A silk ligature was tied around the aorta at the site of the ligamentum arteriosum in beagle puppies aged 8 wk, and the aortic coarctation was corrected 8 mo later, when the aortic peak-to-peak systolic pressure gradient was 6.0 (SD 0.7) kPa. Similar thoracotomy was performed as a sham operation on the control animals on both occasions. One y after the coarctation repair, there was practically no systolic pressure gradient across the aortoplasty site at rest [0.5 (1.0) kPa]. Histologic examination 12 mo after the correction operation showed the medial and intimal layers of the aortic arch in the aortoplasty group (n = 8) were significantly thicker than those in the control group (n = 7) [media 1.86 (0.06) versus 1.78 (0.08) mm and intima 53.2 (13.3) versus 38.3 (10.9) microns, respectively, p less than 0.05 for both]. The thicknesses of both intima and media of the left anterior descending and circumflexing coronary arteries and descending aorta distal to the aortoplasty site were similar in both groups. The increased vascular wall thickness may cause reduced compliance of the vascular bed above the coarctation site and hypertension after correction of the coarctation. Our results support the finding that patients with repaired aortic coarctation have an increased risk of permanent vascular changes.

Animals↗
PubMed1991

Left ventricular function in dogs 1 year after coarctectomy.

Juxtaductal aortic coarctation was surgically created in beagle puppies at the age of 2 months and resected at the age of 10 months, after the development of good collateral circulation. Control dogs undergoing sham operations on each occasion were studied in the same environment. Cardiac catheterization was performed 1 year after the coarctectomy to evaluate the recovery of the heart. Cardiac output, heart rate, end-diastolic pressure, and Vmax were similar in both groups of seven dogs, but the systolic pressure gradient (SPG) over the operated area during isoproterenol infusion was significantly higher in the coarctectomized group, with a mean of 8.9 +/- 6.3 (SD) vs. 0.1 +/- 0.3 mmHg (p less than 0.05). The preejection period [PEP, 58 +/- 8 vs. 47 +/- 5 ms (p less than 0.01)], electromechanical delay [EMD, 18 +/- 3 vs. 13 +/- 3 ms (p less than 0.05)], and isometric contraction time [ICT, 39 +/- 7 vs. 32 +/- 4 ms (p less than 0.05)], were all significantly longer in the coarctation group after isoproterenol infusion. The results demonstrate that, even though cardiac output increased adequately during loading and mechanical pumping efficiency was preserved, excitation-contraction coupling was still prolonged. Thus, an anatomical successful coarctectomy, even at the age of 10 months, does not fully restore left ventricular function in dogs after chronic experimental coarctation.

Animals↗
PubMed1991

Left ventricular responses to experimental aortic coarctation in growing puppies.

The haemodynamic status of 8 coarctated and 7 sham-operated beagle puppies was studied by a catheterization technique at rest and during isoproterenol and volume loading at the ages of 7 (I) and 9 (II) months (5 and 7 months after the experimental coarctation). Proximal aortic systolic and pulse pressures were constantly higher in the coarctation group than in the control group (P less than 0.05), and the systolic pressure gradient across the coarctation was always significantly higher in the coarctation group [I at rest mean 45 +/- 5 (SD) vs 5 +/- 4 mmHg, P less than 0.001, and after I isoproterenol infusion 56 +/- 9 vs 10 +/- 6 mmHg, P less than 0.001, and after I dextran infusion 58 +/- 10 vs 8 +/- 7 mmHg, P less than 0.001]. The time constant of exponential isovolumic left ventricular pressure fall after the isoproterenol tests was longer in the coarctation group (I 28 +/- 8 ms and II, 30 +/- 4 ms) than in the control group (I, 21 +/- 2, P less than 0.05 and II, 19 +/- 3 ms, P less than 0.005), indicating impaired relaxation. The tension time index during the volume loading tests increased in the coarctation dogs (I, 4150 +/- 660 and II, 4080 +/- 810 mmHg s min-1) to higher levels than in the control group (I, 3550 +/- 220, II, 2540 +/- 1140 mmHg s min-1, P less than 0.05 both). Cardiac output, left ventricular end diastolic pressure, inotropic parameters and heart rate were similar in both groups during the infusions.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1991

Cardiac function in hypothermia.

Hypothermia retards cardiac contraction and prolongs the subphases of the cardiac cycle in varying degrees. Six anaesthetized beagle dogs were catheterized and cooled between ice bags until the aortic blood temperature was 25 degrees C and then rewarmed to normothermia. The speed of relaxation decreased to a half from its value in normothermia as indicated by the time constant of exponential isovolumic ventricular pressure fall and by the change in the negative dp/dt. It is suggested that retardation of relaxation is connected with temperature dependent changes in calcium kinetics. Decrease of cardiac output was mediated mainly by decreased stroke volume indicating sympathetic tone in spite of cold narcosis.

Animals↗
PubMed1986

Incidence and prognosis of central nervous system infections in a birth cohort of 12,000 children.

All types of central nervous system (CNS) infections were investigated in a 1966 birth cohort of 12,000 children from Northern Finland followed up from birth to the age of 14. 174 CNS infections occurred in 167 children, 110 boys and 64 girls. The annual incidence of bacterial CNS infections was 36.3/100,000 and that of viral infections 688.0/100 000. It is concluded that bacterial CNS infections were recorded very fully but only 2/3 of the viral infections could be traced, even though the more severe cases were quite well documented. 8/55 children (14.5%) with bacterial meningitis died; the corresponding figure for viral encephalitis and meningitis (excluding mumps) was 3/67 (4.5%). 17/55 (30.9%) developed mental retardation, epilepsy, cerebral palsy or hearing defect or some combination of these after bacterial CNS infection, and 9 (8.1%) after viral infection. The difference with respect to the children who had not experienced CNS infection was statistically significant only for the bacterial infection cases. CNS infections explained 7.6% of all deaths from 28 days to 14 years, 3% of the handicapping cases of cerebral palsy, mental retardation and epilepsy or some combination of these, and 6.6% of the hearing defects.

Adolescent↗