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Biomedical subjects

M Tarkka

Publications and source records attributed to M Tarkka.

72 records · Page 4Linked to original sources
PubMed1985

Renal structure and function in chronic experimental aortic coarctation in dogs treated with antihypertensive drugs.

The possible damaging effect on the kidneys of antihypertensive therapy in aortic coarctation was evaluated experimentally in eighteen canine puppies. Aortic coarctation was carried out in 13 puppies at the age of two months while sham-surgery was carried out on five control puppies. Six coarctated dogs were treated with hydrochlorothiazide, propranolol and prazosin. Antihypertensive therapy was started two months after the operation. Seven coarcted puppies did not receive any treatment. The dogs were followed up for 7 months after which fixation of the kidneys was performed. Antihypertensive therapy decreased blood pressure significantly although the level seen in the control dogs was not attained. There were no signs of deterioration of renal function. Neither light microscopic analysis nor electron microscopy revealed morphological abnormalities in the kidneys of any of the dogs. The present results show that active antihypertensive therapy in experimental coarctation, although not resulting in a normalization but in a significant lowering of blood pressure, is safe and does not cause any morphologic damage in the kidney before corrective surgery. The absence of juxtaglomerular hypertrophy supports the hypothesis that the renin-angiotensin system is not activated in chronic coarctation of aorta.

Animals↗
PubMed1985

Repair of ruptured oesophagus. A case report.

Oesophageal perforation or rupture is a serious condition. Delayed diagnosis is associated with high mortality rate. A method of repair is described, used to cover a lower oesophageal tear with high gastric fundoplication in three cases with delayed diagnosis (greater than 12 h), two of which survived.

Aged↗
PubMed1984

Surgery of thoracoabdominal aortic aneurysms.

Arteriosclerotic aneurysm of the thoracoabdominal aorta, involving one or more visceral branches, was successfully operated on in eight patients. Two of the aneurysms had ruptured. The left diaphragm-splitting thoracoabdominal incision through the 8th intercostal space, using a retroperitoneal route, gave unrestricted exposure. A temporary aortofemoral shunt effectively protected abdominal organs and spinal cord from perioperative ischemic damage. The step-by-step reattachment technique into ready-made side limbs in the woven Dacron graft ensured that visceral and renal ischemic times remained within acceptable limits. Perfusion cooling of the abdominal organs was done in one patient in whom shunt could not be used. A standby autotransfusion device was life-saving in another case. All the patients recovered without major complications. Moderate elevation was found as regards serum creatinine levels in seven patients and liver enzymes in four patients, but the values normalized within a month. No paraplegic complications occurred, although all bleeding intercostal and lumbar arteries were ligated intra-aneurysmatically in seven of the eight patients. Seven patients are well 20 to 60 months postoperatively, with patent and well functioning grafts. One patient died of lung cancer after 7 months. Four of the 18 revascularized arteries in three patients were shown by control angiography to be occluded, but without serious sequelae. Our experience suggests that most thoracoabdominal aortic aneurysms are suitable for surgical correction, with acceptable risk. Elective surgery is therefore recommended.

Adult↗
PubMed1983

Prevention of morphological changes of great arteries in coarctation of the aorta with antihypertensive therapy.

The possibility of preventing morphological changes in arterial walls in coarctation of the thoracic aorta with antihypertensive therapy was evaluated in an experimental study on dogs. Seven mongrel dogs weighing 2350-2980 g were operated upon at the age of 2 months. Antihypertensive therapy with a diuretic (hydrocholothiazide 25 mg/day), beta-blocker (propranolol and 80 mg/day) and vasodilatator (prazosin ad 40 mg/day) was started 1 month after the experimental coarctation was produced in the animals. Blood pressure decreased significantly, although not to the level of the control group. Seven months after the coarctation a perfusion fixation was done. Morphometrical light microscopic analysis was performed on the coronary and cerebral arteries. The histochemical findings in the aorta were analysed qualitatively, as was the amount of lipid in the coronary and the middle cerebral arteries. Electron microscopic studies were performed on the coronary artery. The findings were compared to the control and coarctated (non-treated) groups studied earlier (Uhari et al., 1982). Active antihypertensive therapy prevented all the major morphological changes previously reported to occur in coarctation. We suggest that active antihypertensive therapy started immediately after the diagnosis of coarctation might improve the prognosis of the patients with aortic coarctation by preventing morphological changes in the great arteries.

Animals↗
PubMed1982

Morphology of the great arteries in chronic experimental coarctation in dogs.

Vascular changes of the great arteries could be one explanation for the serious complications and persistent hypertension after coarcectomy among patients with coarctation. This possibility was studied by evaluating the morphology of the coronary artery, aorta and middle cerebral artery in 7 experimental 9-month-old dogs in which a coarctation of the thoracic aorta had been made at the age of 2 months. A classical coarctation syndrome with high blood pressure and intense collateral circulation developed during growth. Five sham-operated dogs living in the same laboratory environment served as a control group. Morphometric measurements showed medial thickening of the coronary artery wall in the coarctated dogs (135 vs 103 microns, P less than 0.05). The relative amount of glycosaminoglycans of the media was also greater in the study group (14.8% vs 8.1%, P less than 0.02). The relative number of medial nuclei was significantly greater in the coarctated dogs (P less than 0.025), reflecting medial hyperplasia. Vacuolated smooth muscle cells and fragmented elastic membranes were found in the media of the aortas of coarctated animals. No significant differences between the groups were found in the cerebral arteries. It is suggested that re-evaluation of the optimal age of patients with coarctation for surgical repair is obviously necessary.

Animals↗
PubMed1981

Renal blood flow in high and low positions of aortal catheter in rabbits.

The effect of aortal catheterization on renal blood flow (RBF) was evaluated in seven rabbits weighing 2500 to 3500 g. RBF was measured 21 times from 13 kidneys during aortal catheterization with an isotope (133 Xe) technique. The catheter was positioned in the aorta of each rabbit both above and below the origins of the renal arteries. The results of these two measurements were compared. Two phases of RBF, a fast first phase and a slow second phase, were determined. The fast phase of RBF was 5.3 ml/g/min, when it was in the high position. The results of the slow phase were identical, 0.16 ml/g/min, in both positions. No significant statistical difference could be found according to the phase of the catheter (paired t-test). These results in rabbits suggest that the aortal catheter does not cause any immediate decrease in RBF. This finding has clinical importance in aortal catheterization in neonates to obtain arterial blood samples. When considering the position of the aortal catheter in neonates factors other than RBF should be taken into account.

Animals↗
PubMed1977

Traumatic splenic rupture.

71 patients with traumatic splenic rupture are reported. Most had severe associated injuries. In 44 patients the mechanism of trauma was blunt, in 10 penetrating, and in 17 iatrogenic, occurring most commonly (11/17) during operations for peptic ulcer. Splenectomy gave use to thrombocytosis which reached its peak about 2 weeks and returned to normal within one month after operation. Postoperative complications occurred in 24 of the 60 surviving patients (40%) of which most, 17 patients (30%) were infectious in origin. One patient developed deep venous thrombosis. Mortality was 16%. Associated injuries were the main cause of death in most patients (9/11), the ruptured spleen being responsible for only 2 deaths. None of the 17 patients with injury to the spleen alone died, whether associated with fractures of the left lower ribs or not. Primary unconsciousness, shock on admission, and multiple injuries, especially renal and hepatic, increased the mortality rate markedly. The necessity of drainage, the possibility of increased susceptibility of splenectomized patients to infection and thromboembolic complications and their prevention are briefly discussed.

Accidents↗
PubMedDate not supplied

Spontaneous oscillation of systemic arterial pressure during cardiopulmonary bypass in the dog.

Cardiopulmonary bypass and an open-heart operation were carried out on four beagle dogs kept under ketamine anesthesia. Oscillation of systemic arterial pressure during this maneuver was observed in three dogs and oscillation of pulmonary arterial pressure in two dogs. Mean amplitude of the oscillation in systemic arterial pressure was 6 to 7 mm Hg and that in pulmonary arterial pressure about 1 mm Hg. The duration of an oscillatory wave was about 20 s. Systemic arterial pressure was 130 to 150 mm Hg. The oscillation disappeared in two dogs when weaning from the bypass. These oscillations resemble those observed in humans during cardiopulmonary bypass and also those observed in experimental animals without bypass conditions.

Animals↗
PubMedDate not supplied

Fear and anxiety in patients awaiting coronary artery bypass grafting.

OBJECTIVE: The purpose of this study was to identify the prevalence of fear and anxiety in patients awaiting coronary artery bypass grafting and the factors associated with high fear and high anxiety. DESIGN: The survey included 240 patients placed on the waiting list for coronary artery bypass grafting at one hospital. SUBJECTS: Two hundred and seven patients completed the questionnaire. INSTRUMENTS: The Bypass Grafting Fear Scale, the State-Trait Anxiety Inventory, and the Hospital Anxiety and Depression Scale were used. RESULTS: Half of the patients experienced low fear and anxiety. Twenty-five percent had high fear, but only 5% had high anxiety. Patients who felt high fear were mainly women, had no vocational education, were on sick leave, were depressed, had a tendency towards anxiety, and had a short wait for operation. Patients who displayed medium or high anxiety were mostly under 55 years of age and had depression, but only low or no pain. CONCLUSIONS: The results facilitate better identification of predictors of high fear and anxiety as well as direct support and information for those patients.

Adult↗
PubMedDate not supplied

Total lymphoid irradiation in the treatment of early or recurrent heart rejection.

UNLABELLED: Total lymphoid irradiation (TLI) has been shown experimentally to induce a state of partial tolerance when administered before organ transplantation. Anecdotal reports in clinical transplantation have suggested efficacy of TLI in the treatment of recurrent rejection after heart transplantation. To further assess the safety and efficacy of TLI, 19 patients were entered into a protocol of TLI for the treatment of recurrent or early severe rejection despite conventional therapy. Rejection rate decreased from 1.3 episodes/month before TLI to 0.53 during TLI and 0.07 after TLI (p < 0.0001). Infections increased during TLI (possibly related to recent augmented immunosuppression before TLI), but all infections were successfully treated. One death occurred after TLI from acute allograft rejection. White blood cell (WBC) and platelet counts were depressed during and after (3 months) TLI. Frequent adjustments of dosing interval and, occasionally of the dosage were required to control WBC and platelet counts. Five patients experienced transient WBC of less than 1000/ml. More rejection episodes (and thus greater overall immunosuppression) before TLI and a lower tolerated dose of azathioprine before TLI predicted (by multivariate analysis) a lower WBC during TLI. CONCLUSIONS: (1) TLI is an effective adjunct for the intermediate control of early or recurring acute allograft rejection. (2) Close surveillance of WBC and platelets with appropriate adjustment of TLI dose and interval is necessary during TLI therapy. (3) The long-term benefits, possible late deleterious effects, and potential role of TLI as induction therapy remain to be elucidated.

Adolescent↗
PubMedDate not supplied

Methotrexate pulse therapy in the treatment of recurrent acute heart rejection.

Despite cytolytic induction therapy and triple-drug immunosuppression, acute allograft rejection continues to cause important morbidity and occasional death after heart transplantation. Between November 1, 1988, and May 1, 1990, 24 patients received methotrexate pulse therapy for recurrent or persistent acute rejection despite methylprednisolone, OKT3, or antithymocyte globulin therapy. Methotrexate was administered as a daily oral dose of 2.5 to 15 mg on 1 day/week over 3 weeks (longer in 15 patients because of either severe leukopenia with temporary interruption of therapy or recurrent rejection during methotrexate therapy) with reduction or discontinuation of azathioprine. Rejection incidence was reduced from 1.1 episodes/patient month before methotrexate therapy to 0.2 episodes/patient month after completion of therapy (p = 0.0001). Two patients died within 3 months after treatment, one of cytomegalovirus pneumonia and one of lymphoma. Mean white blood count (WBC) fell from 6900 per ml before methotrexate therapy to 3700 during the first month of methotrexate therapy (p = 0.0005). The lowest WBC typically occurred about 3 weeks after starting methotrexate therapy, and a transient WBC of less than 1000/ml developed in seven patients. By multivariable analysis, the WBC 1 month after starting methotrexate therapy was significantly related to greater bone marrow suppression (lower WBC), immediately before methotrexate therapy, greater overall immunosuppression (more rejection episodes) during the 3 months before methotrexate therapy, and a higher total dose of methotrexate. The following conclusions can be drawn: (1) Methotrexate is a useful adjunct in the treatment of recurrent or persistent rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMedDate not supplied

Persistence of collateral circulation after correction of aortic coarctation.

The persistence of collateral circulation was evaluated one year after the correction of experimental aortic coarctation (CoA) by assessing renal perfusion with the Xenon 133-washout method and measuring distal aortic blood pressure during cross-clamping of the thoracic aorta. CoA was created in 7 puppies at 2 months of age and was corrected after a follow-up with a venous patch when the dogs were 9 months old. Two of the dogs were lost during the corrective operation due to anaesthetic complications. Four sham-operated dogs served as controls. One year after correction of CoA, four of the dogs had a pressure gradient of less than 5 mmHg at the site of CoA and one a pressure gradient of 15 mmHg. In renal perfusion measurements a mean decrease of 49% and 96% was found in the study and control groups, respectively. Blood pressures in the distal aorta decreased 47% and 83%, respectively. Two dogs in the study group had a distal blood pressure under 50 mmHg and their renal perfusion decreased markedly. Collateral circulation decreased with time after a good anatomic correction of CoA, so that one year after correction of experimental CoA about one half of the initial collateral capacity remained. This suggests that in most reoperations performed at least one year after the primary corrections, temporal shunting or a left side bypass is necessary to ensure sufficient circulation in the distal organs.

Animals↗