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Biomedical subjects

K Virtanen

Publications and source records attributed to K Virtanen.

At least 19 recordsLinked to original sources
PubMed1998

Comparison of sotalol and metoprolol in the prevention of atrial fibrillation after coronary artery bypass surgery.

New-onset atrial fibrillation (AF) is frequent after coronary artery bypass grafting (CABG), and beta-blockers decrease its incidence. To examine whether a beta-blocker with class III properties is superior to a pure one, 191 consecutive patients undergoing CABG were randomized to receive oral sotalol, 120 mg daily (n = 93), or metoprolol, 75 mg daily (n = 98), postoperatively. The doses were adjusted if beta-blockade was inadequate or excessive. AF occurred in 16 (16%) of 98 sotalol patients and in 30 (32%) of 93 metoprolol patients (p < 0.01). Symptoms related to beta-blockade or proarrhythmia did not appear. After CABG, sinus heart rate increased in both groups (p < 0.001) but less in the sotalol patients (p < 0.001) throughout the postoperative period. Corrected QT duration (by the Bazett equation) was prolonged after the operation in both groups (p < 0.001), whereas uncorrected QT duration at similar heart-rate levels were prolonged only in sotalol patients (mean increase, 31 ms; 95% confidence interval, 2042 ms; p < 0.01). Uncorrected QT durations at similar heart-rate levels were longer during sotalol (compared with metoprolol) treatment (p < 0.05). Heart rates or QT durations did not differ between the patients with or without AF. In conclusion, sotalol significantly reduces the incidence of AF after CABG. Although a marked class III effect is demonstrated with relatively low doses (as prolonged ventricular repolarization) in direct comparison unbiased by any rate correction, its contribution as an enhanced antifibrillatory mechanism in the postoperative state remains unconfirmed.

Anti-Arrhythmia Agents↗
PubMed1998

The effect of prosthesis disinfection on salivary microbial levels.

The aim of this study was to evaluate how the soaking of dentures in a disinfection solution affects salivary microbe counts and stomatitis of partially dentate patients. Patients soaked their dentures for 4 weeks randomly both in a disinfection solution and in a placebo solution. Mutans streptococci, lactobacilli and yeast counts were measured before and after each test period and also the flow rate, buffer capacity and pH of saliva were registered. Disinfection decreased all microbe levels investigated, but only lactobacilli counts decreased significantly. Placebo treatment had either no effect on salivary microbe counts or they increased slightly. Disinfection caused some reduction of the mucosal inflammation under the denture base, but could not completely remove stomatitis during the 4-week test period.

Adult↗
PubMed1997

Surgical treatment of acute myocardial ischaemia related to coronary angioplasty with special reference to use of perfusion balloon catheter and long-term outcome.

Twenty of 569 consecutive patients (3.5%) undergoing percutaneous transluminal coronary angioplasty required emergency coronary artery bypass grafting for acute closure of the dilated vessel. In seven patients an intracoronary autoperfusion balloon catheter was inserted to ensure antegrade blood flow across the injured zone of the coronary artery. The time needed for completion of the bypass grafts ranged from 100 to 399 minutes (mean 180 minutes). An average of 1.9 coronary artery bypasses was inserted. In total, 11 of the 20 patients (55%) developed new Q waves and had elevated CK-MB levels. However, the myocardial infarction rate was only 14% in those with a perfusion balloon catheter as against 77% in those without one. The insertion of a ball-out catheter permitted greater utilization of the internal mammary artery as a bypass graft. Angiographic follow-up was conducted after a mean of 28 months (19 patients). The patency rate of the bypass grafts placed in the emergency setting was relatively good (91%). Thallium tomography revealed a scar of variable size in all 17 patients studied and a reversible exercise perfusion defect requiring coronary reangioplasty in three patients. In conclusion, the insertion of a perfusion balloon catheter after abrupt coronary occlusion during coronary angioplasty solved the problems of acute myocardial ischemia and markedly lowered the definite myocardial infarction rate. This technique ensures favourable haemodynamic conditions for emergency myocardial revascularization.

Angioplasty, Balloon, Coronary↗
PubMed1996

Myocardial function in children and adolescents after therapy with anthracyclines and chest irradiation.

Cardiotoxicity is a potential adverse effect of anthracycline (A) therapy. Radiotherapy (XRT) may also cause a variety of cardiac complications. The purpose of the present study was to evaluate these cardiac side-effects in children and adolescents treated for cancer. We assessed the cardiac status of 91 patients, divided into three groups: Group A (n = 53) had anthracyclines at a mean cumulative dose of 410 mg/m2, group A+XRT (n = 26) had both chest irradiation (XRT) and A (mean 360 mg/m2), and group XRT (n = 12) had XRT alone. The patients differed from the controls in both systolic and diastolic indices of myocardial function. In echocardiography, the left ventricular (LV) contractility was abnormal in 32% in group A, in 50% in group A+XRT, and in 8% in group XRT. In radionuclide cineangiography, the LV ejection fraction was subnormal in 19% in group A, in 24% in group A+XRT, and in 1 patient in group XRT. A higher cumulative dose of A predicted decreased contractility. Treatment with A and/or XRT often leads to cardiotoxicity. Although in most cases this cardiotoxicity seems to be mild and subclinical, the long-term clinical sequelae merit further evaluation.

Adolescent↗
PubMed1995

Polymorphonuclear leukocyte chemotaxis induced by zinc, copper and nickel in vitro.

Metallic dental restorations and prosthetic constructions are susceptible to corrosion in oral environment, resulting in the release of various heavy metal ions. Chloride salts of zinc, copper, nickel, chromium, iron and gold were tested for their ability to promote the migration of polymorphonuclear leukocytes (PMNs). Using a modified Boyden chamber assay for chemotaxis zinc, copper and nickel enhanced the migration of PMN cells in concentration range of 0.5-1.0 mM, whereas no augmentation in migratory activity was noted using chromium or iron. In contrast, an inhibition in migratory activity was observed in cells directed toward gold ions. Exposure of cells to zinc, copper or nickel ions induced an orientation reaction in leukocytes in a similar fashion as the polarization reaction induced by a potent peptide chemoattractant, N-formylmethionylleucylphenylalanine (fMLP), in these cells. Exposure of PMN cells to zinc or nickel in chemotactic concentrations stimulated the chemotaxis of these cells to fMLP 2-fold, whereas pretreatment of the cells with zinc prior to assay markedly decreased the subsequent chemotactic migration of the cells to this metal or to fMLP. The enhanced locomotion of PMN cells induced by zinc, copper or nickel ions was found to be in greater extent due to an increase in directed migration (chemotaxis) rather than an augmentation in random movement (chemokinesis) as assessed by Zigmond-Hirsch checkerboard analysis. These results suggest that zinc, copper and nickel ions attract leukocytes by inducing and promoting the chemotactic response in these cells, which may modulate the inflammatory response of host tissue around such metals.

Animals↗
PubMed1995

Anorectic effect of metformin in obese Zucker rats: lack of evidence for the involvement of neuropeptide Y.

The hypothalamic neuropeptide Y content and preproneuropeptide Y mRNA expression were studied in metformin-treated (300 mg/kg orally for 12 days), in pair-fed and in ad libitum-fed obese Zucker rats in order to elucidate possible mechanisms involved in the anorectic and body weight reducing effect of chronic metformin treatment in genetically obese Zucker rats. In addition the acute influence of metformin on food intake was studied by comparing its effects after oral and parenteral administration. The concentration of neuropeptide Y in the hypothalamic paraventricular nucleus was significantly higher in the metformin-treated and pair-fed rats when compared to the control animals. The expression of preproneuropeptide Y mRNA in the arcuate nucleus was similar in all three treatment groups. Both chronic metformin treatment and pair-feeding markedly lowered hyperinsulinaemia in these animals. A single subcutaneous dose of metformin (300 mg/kg) reduced food intake only in obese animals, while the same dose of metformin given orally did not affect food intake in either lean or obese animals. It is concluded that the treatment with metformin and pair-feeding, which results in comparable reductions in food intake, body weight gain and hyperinsulinaemia, similarly increase neuropeptide Y concentrations in the paraventricular nucleus while not affecting preproneuropeptide Y mRNA expression in the arcuate nucleus. The increase in hypothalamic neuropeptide Y content may be secondary to the reduction in hyperinsulinaemia during metformin treatment and pair-feeding. Thus, the anorectic effect of chronic metformin treatment cannot be explained by changes in content or expression of hypothalamic neuropeptide Y.

Administration, Oral↗
PubMed1995

Cardiopulmonary evaluation of exercise tolerance after chest irradiation and anticancer chemotherapy in children and adolescents.

OBJECTIVE: The aim of the study was to evaluate the cardiopulmonary exercise tolerance in children and adolescents after chest irradiation and anticancer chemotherapy. METHODS: We studied 30 subjectively asymptomatic patients aged 8 to 25 years treated for pediatric malignancies with chest irradiation (XRT) +/- chemotherapy. The median interval since XRT was 7 (range, 2 to 13) years. The median XRT dose for mediastinum and/or lungs was 2550 (range, 1000 to 5100) cGy. The median cumulative dose of anthracyclines was 250 (range, 0 to 480) mg/m2. Cardiac function and exercise tolerance were evaluated by electrocardiography, echocardiography, radionuclide cineangiography, and exercise test with gas exchange analysis. RESULTS: The patients differed from normal controls in systolic indices of myocardial function. In echocardiography, the left ventricular contractility was abnormal in 14/30 patients. In radionuclide cineangiography, the left ventricular ejection fraction was subnormal in 6/30 patients, and in 9/30 patients the rise in ejection fraction during exercise was inadequate (< 5%). In exercise testing, the mean (+/- SD) maximum workload attained was 2.7 (+/- 0.7) watts/kg, and the mean (+/- SD) maximum oxygen consumption was 35.4 (+/- 9.7) mL/min/kg. Both variables were < 80% of predicted values in 11 patients. CONCLUSIONS: XRT and anticancer chemotherapy very often lead to late cardiopulmonary toxicity and impaired exercise tolerance. Although in most cases this toxicity seemed to be mild and subclinical, the long-term clinical sequels merit further evaluation.

Adolescent↗
PubMed1994

Effects of bone marrow transplantation on myocardial function in children.

Of 41 pediatric patients currently alive after total body irradiation (TBI) and bone marrow transplantation (BMT), 30 (allogeneic 20, autologous 10) participated in the study. Pre-transplant therapy included high-dose cyclophosphamide (CY) and TBI (n = 12), high-dose CY alone (n = 4), high-dose Ara C and TBI (n = 5), cisplatinum, high-dose melphalan, VP-16 and TBI (n = 9). Acute cardiotoxicity was suggested by a > 15% decrease in the QRS voltage sum of the limb leads in all patients. Late cardiotoxicity was evaluated 0.5-10 years (median 5 years) post-transplant by ECG, chest radiograph, radionuclide cineangiography (RNCA) and echocardiography (ECHO). Six patients had a persistent decrease in the QRS amplitudes. They were all asymptomatic but had abnormal systolic function at the time of the study. BMT patients differed from their controls in the mean values of both the systolic and diastolic indices of myocardial function shown by RNCA and ECHO. Treatment was associated with decreased myocardial contractility. Isovolumic relaxation time and deceleration time were longer in BMT patients than in controls. Myocardial damage seemed to be worst after CY while high-dose Ara C was tolerated best. We conclude that both acute and late cardiotoxicity may occur after BMT, calling for long-term cardiac follow-up.

Adolescent↗
PubMed1993

Failures in the osseointegration of endosseous implants.

A total of 68 patients, 26 men and 42 women, aged 21 to 86 years, were treated with 204 endosseous implants (TPS, ITI, Bonefit, or Biolox) from 1985 to 1990. They were examined at their latest recall visit approximately 22.5 months after surgery, the range varying greatly between the implant systems used (from 4 to 60 months). Fourteen implants were lost during the observation period because of failures in osseointegration. There were no statistically significant differences in success rates between the implant systems during the observation period. The Periotest values, however, differed between the Bonefit and ITI implants in maxillae (P < .001) and mandibles (P < .01), and between successful and failed TPS implants (P < .001, unpaired t test). In four of the failures, all ITI implants, the prosthetic restorations (fixed dentures and single crowns) had been lost. All other failures were treated by using the previous complete denture. Possible causes of failure included advanced age and poor general health of the patient, complications in the surgical procedures, and compromised oral hygiene.

Adult↗
PubMed1992

Long-term blood flow potentials in sequential internal mammary artery grafts. Exercise thallium scan for myocardial perfusion study.

In two groups of patients, coronary artery bypass surgery for angina pectoris included internal mammary artery (IMA) sequential grafts (group I) or single grafts (group II). At postoperative angiography all grafts were patent. In addition, the patients received on average 1.8 vein grafts into other coronary arteries. The mean interval to postoperative follow-up was 9.5 years in group I and 9.7 years in group II. The preoperative incidence of acute myocardial infarction was 44% and 45% in groups I and II. Exercise thallium scan at follow-up showed IMA graft-related ischemia in 33% of the patients with sequential graft and in 64% of those with single graft (ns). Our results indicated that sequential IMA grafts functioned at least as well as single grafts and maintained adequate myocardial supply even 10 years postoperatively. Internal mammary arteries are superior graft material and can be recommended both as single and as sequential graft in coronary artery bypass surgery.

Aged↗
PubMed1991

Internal derangement of the temporomandibular joint: a histochemical study.

The purpose of this study was to correlate histologic findings in temporomandibular joint (TMJ) condyles and discs with their macroscopic appearance at surgery. The 24 patients with internal derangement of the joint included 20 women and 4 men (mean age, 37 years; range, 18 to 61 years). The tissue lesions varied in degree from mild soft-tissue fraying and bone remodeling to extensive resorption and new cartilage and bone formation with high phosphatase enzyme activities, and even to loss of articular soft tissue and breakdown of cortical bone. Reactions may arise in the hard tissues before they occur in the articular surface layers.

Acid Phosphatase↗
PubMed1990

Indications for and risks in reoperation for coronary artery disease.

Seventy-one coronary artery bypass grafting (CABG) reoperations were performed during a 17-year period, comprising 2.7% of all CABG operations. The main indication (in 87%) was vein graft failure alone or combined with other causes. Progression of disease in native coronary arteries was the sole indication in only 4 of the 71 cases. There were seven perioperative deaths, mainly due to myocardial infarction. Significant perioperative complications arose in 36 cases, including intraoperative lesion of a previous left internal mammary graft (16.2%) or of the right ventricle or anterior descending branch of the left coronary artery (2.8%). Postoperative low output syndrome appeared in 13 patients (18.3%), in seven of whom myocardial infarction was verified. Postoperative bleeding required resternotomy in six cases (9.1%). Because of the heightened operative mortality and morbidity risks, indications for redo CABG should be individualized. A well functioning internal mammary artery graft may be a relative contraindication. Accurate knowledge of the previous operation is essential and, especially in young patients, the possibility of reoperation should be taken into consideration at initial CABG.

Adult↗
PubMed1989

Right gastroepiploic artery as a coronary bypass graft.

Between November 1987 and April 1988, the right gastroepiploic artery (GEA) was used as a coronary artery bypass graft in 11 patients, 9 men and 2 women. In 1 of them, the GEA was used because no veins were available; in the others, the GEA was used to avoid the use of vein grafts. The GEA was anastomosed to the right coronary artery in all patients, and internal mammary artery grafts were used to bypass the left anterior descending and circumflex coronary arteries. All patients survived the operation. There were no early and, to date, there have been no late complications of the abdominal component of the operation. Postoperative coronary angiography showed a patent right GEA in 9 patients (82%). In 1 patient the GEA was occluded, probably because of an enlarged liver. If the long-term patency of right GEA grafts is similar to that of internal mammary artery grafts, wider use of this viable graft is indicated.

Adult↗
PubMed1989

Results of reoperations for coronary artery disease.

Seventy-one patients undergoing reoperation for coronary artery disease were examined on average 2.5 years postoperatively. Operative mortality was 9.9% and late mortality 6.3%. 88% of the patients improved subjectively, and although only 7.8% were angina-free, 79.9% were in NYHA Class I or II. All patients who had been working before reoperation returned to work, and either patients who were on sick-leave before resumed their activities. A follow-up examination was performed in 21 patients with a follow-up time of more than three years. The mean peak work capacity did not change after reoperation and also the ST changes during the bicycle ergometer exercise test were the same after reoperation. The mean ejection fraction diminished from 54 +/- 15.5% to 44.7 +/- 15.2%. In thallium perfusion studies areas of hypoperfusion were observed in 14 cases (67%). Coronary angiograms showed 3.0 +/- 1.0 patent anastomoses at the follow-up examination; 76% of the anastomoses performed in the reoperations were patent. It can be concluded that although the objective results of repeat myocardial revascularisation in this material are not optimal, the subjective improvement of the patients was satisfactory, and in the majority of cases reoperation ensures an acceptable quality of life for years.

Coronary Artery Bypass↗
PubMed1986

Surgical and prosthetic treatment of the atrophic mandible.

Two vestibuloplasty methods and a muscle-formed method for improving the retention and stability of complete mandibular dentures were compared in 19 edentulous patients with advanced mandibular bone resorption. The resorptive changes in the alveolar crest and any relapse in the extended vestibule after surgery were monitored for 2 yr. Simultaneous production of the first new complete dentures, to which the labial plate is added during the surgical procedure, and firm circummandibular fixation during primary healing will guarantee the best surgical and prosthetic results. This order of treatment also eliminates unnecessary surgical procedures. A muscle-formed method for extending the baseplate of a complete mandibular denture was found to be a useful alternative for patients with highly advanced mandibular bone resorption.

Adult↗
PubMed1985

Ruptured coronary artery aneurysm--a rare cause of hemopericardium.

Large coronary artery aneurysms may interfere with coronary flow, cause compression, and/or may rupture. Circulatory shock from thrombosis and rupture of an aneurysm of the right coronary artery in a patient is reported here. This formation, 7 cm in diameter, was visible by computed tomogram but the diagnosis was revealed only during surgery. The successful treatment, using aneurysmectomy and reconstruction with an interposed saphenous vein graft, is described.

Aneurysm↗
PubMed1984

Postoperative disc entrapment following cardiac valve replacement--a report of ten cases.

The sudden jamming of a prosthetic valve disc is one cause for postoperative hemodynamic deterioration. This complication occurred in 10 instances (2% of disc valves implanted), resulting in 4 fatalities. In 6 patients the disc entrapment was a complication following mitral valve replacement, and in 4 others the malfunction followed aortic valve surgery. The entrapment of the disc occurred on the second postoperative day in 3 patients. Two of these were due to an unresected chordal strand becoming wedged between the disc and valve rim of a Björk-Shiley mitral prosthesis and resulted in death. In the third patient, the aortic valve disc became attached to the Björk-Shiley composite aortic graft following the repair of an aortic dissection. A firm blood clot had formed between the graft and the oversewn aortic wall. This patient recovered after cardiopulmonary resuscitation and subsequent reoperation. The remaining cases developed while the patients were still either on the operating table or in the recovery room. The mechanisms of the disc entrapments are presented and the significance of an early correct diagnosis and urgent surgical correction is underlined.

Adult↗