Aortic valve replacement by a pulmonary homograft

Minor experience still exists in our country with regard to the use of valve homografts in cardiac surgery. Only a few implantations have been performed in cases of right ventricular outflow tract reconstruction in addition to our own experience in cases of infective endocarditis of the aortic valve. We present a case of aortic valve replacement by using an antibiotic-sterilized fresh pulmonary valve autograft. The case is described and the possible advantages of the use of pulmonary allografts in the aortic position are discussed.     

The Na(+)-H+ exchanger is stimulated and cell volume increased in lymphocytes from patients with essential hypertension.

A stimulation of the Na(+)-H+ exchanger has been shown in platelets of hypertensive man and lymphocytes of spontaneously hypertensive rats. In the present paper, human mononuclear leukocytes (HML) were investigated in 12 patients with essential hypertension with regard to the activity of the Na(+)-H+ exchanger and HML volume. The swelling of HML in isotonic sodium propionate was determined using a Coulter Channelyzer. Compared with matched normotensives, the cell volume of HML in a physiological buffer was significantly increased in essential hypertension (P less than 0.05). The amiloride-inhibitable rate of cell swelling in isotonic sodium propionate was also increased in HML from hypertensives. Amiloride (400 mumol/l) abolished the difference in cell volume within 1 min. These data show a functional swelling of HML in essential hypertension, probably due to an activation of the Na(+)-H+ exchanger. If also representative of smooth muscle cells, these findings could explain hypertensive vessel wall hypertrophy, in part, as functional cell swelling.     

Proposal of a dose-response relationship between aluminium welding fume exposure and effect on the central nervous system.

Exposure to high levels of aluminium can affect the human central nervous system. Abnormalities of psychomotor function have been observed among haemodialysis patients with mean aluminium concentrations in serum of about 60 micrograms/l. According to our own data this corresponds to a urinary level of about 330 micrograms Al/l in aluminium-exposed welders without kidney failure. This post-shift urinary level of aluminium is estimated to be attained after 40 years of exposure to a welding fumes at an environmental concentration of approximately 1.6 mg/m3 of aluminium. An increased prevalence of effects on the nervous system was observed among welders exposed to aluminium fumes for more than 13 years. This finding supports the concept of cumulative toxicity due to aluminium exposure. On the basis of these observation, we suggest that the level of aluminium in welding fumes should not exceed 1 mg/m3.     

Detection of frequent allelic loss on proximal chromosome 17q in sporadic breast carcinoma using microsatellite length polymorphisms.

Analyses of losses of heterozygosity and linkage studies have implicated a gene(s) on chromosome 17q in the genesis of sporadic and early-onset familial breast carcinomas, respectively. To define the critical region of 17q, we examined DNAs from a series of 20 sporadic breast carcinomas and corresponding blood samples for allelic losses of chromosome 17q using microsatellite length polymorphisms. With these highly informative markers (average heterozygosity, 0.73), we observed frequent deletions of 17q at several loci. We found that D17S250 was deleted in 50% (7 of 14), THRA1 in 79% (11 of 14), D17S579 in 59% (11 of 19), NME1 in 29% (5 of 17), MPO in 36% (4 of 11), and GH in 25% (4 of 16) in the tumor set examined. A common region of deletion was found that was flanked by D17S250 to D15S579. These markers have recently been localized to a 6-cM interval of proximal chromosome 17q in bands 17q11.2-q21 and map within the region of the early-onset familial breast cancer locus, implying that the same gene or genes may be involved in both sporadic and familial breast tumors. Thyroid hormone receptor alpha and retinoic acid receptor alpha are two potential candidate genes in this region.     

Myocardial ultrastructure in the isolated rabbit heart exposed to dopamine, dobutamine, isoprenaline, G-strofanthin, xamoterol and hypoxia.

The isolated spontaneously beating heart was used for comparing the effects of hypoxia and positive inotropic drugs on myocardial ultrastructure. Hypoxia gives a significant decrease in the volume fractions of mitochondrial cristae relative to the total mitochondrial volume (Vvmcristae) and a significant increase in the volume fraction of mitochondrial matrix relative to the total mitochondrial volume (Vvmmatrix), but changes in volume fractions of mitochondria (Vvmitochondria) and myofibrils (Vvmyofibrils) were absent. Significant changes in ultrastructure in hearts treated with dopamine (0.6 microM), dobutamine (90 nM), G-strofanthin (0.25 microM), xamoterol (32 nM) and isoprenaline (0.15 microM or 15 nM) were absent. Furthermore, myocardial effects in the isolated rabbit heart without exposure to any treatment showed a significantly decrease in oxygen consumption after 90 min. and a significant decrease in frequency of contractions after 120 min. perfusion time, but no change in contractility was seen. We conclude that this experimental model is useful in studies of positive inotropic drugs.     

Enhancement of spontaneous fibrinolytic activity in diabetic retinopathy.

The fibrinolytic system was studied in 96 patients with type I diabetes mellitus. Patients were grouped according to their degree of retinopathy; 38 patients with no evidence of retinopathy, 28 patients with background retinopathy and 30 patients with proliferative retinopathy. Thirty healthy individuals served as controls. The basal fibrinolytic activity as measured by clot lysis time and t-PA activity was increased in diabetic patients. This was associated with low levels of plasminogen activator inhibitor. Increased levels of D-dimer in diabetic patients further indicate enhanced in vivo fibrinolysis. The increase in fibrinolytic activity was highest in diabetics without retinopathy, and decreased with increasing retinopathy. Endothelial release of t-PA after venous occlusion was not different between controls and all diabetic groups. These findings suggest that in type I diabetics the fibrinolytic system is in an activated state. With worsening of retinopathy this increase in fibrinolytic activity diminishes.     

Morphofunctional changes in the small intestine of children with food allergy

Children with food allergy underwent allergologic and gastroenterologic examinations using esophagogastroduodenojejunoscopy. Impairment of the jejunum in the form of jejunitis associated with function abnormality as shown by the loading tests was revealed. It is concluded that the given patients: group should be examined for the morphofunctional status of the upper gastrointestinal tract.     

Characterization of contraction-mediating prostanoid receptors in human hand veins: effects of the thromboxane receptor antagonists BM13,505 and AH23848

The effects of prostaglandin F2 alpha, prostaglandin E1, prostaglandin E2 and the thromboxane A2 analogue U46619 were determined in ring segments of human hand veins. All prostanoids except prostaglandin E1 elicited contraction. The order of potency was U46619 greater than prostaglandin F2 alpha greater than prostaglandin E2. The thromboxane receptor antagonists BM13,505 and AH23848 both caused a parallel rightward displacement of the concentration-response curve for U46619 without depression of the maximum contraction, suggesting competitive antagonism. Schild plots for both antagonists yielded regression lines with slope indices not significantly different from unity. The pA2 values for BM13,505 and AH23848 were 7.9 and 8.4 respectively. Both antagonists also effectively inhibited prostaglandin F2 alpha-induced contractions. However, AH23848 significantly reduced the maximum response, and the results with BM13,505 gave no clear indication of the type of inhibition. In vein segments submaximally contracted by 5-hydroxytryptamine, prostaglandins E1 and E2 produced a biphasic response with a relaxation at low and a contraction at high concentrations. Prostaglandin F2 alpha and U46619 failed to elicit relaxation under these conditions. However, in the presence of either thromboxane receptor antagonist, prostaglandin F2 alpha but not U46619 produced a relaxation. The results are compatible with the presence of at least two prostanoid receptors in human hand veins, a contraction-mediating thromboxane receptor and an as yet unclassified receptor eliciting relaxation. U46619 was a potent agonist at the thromboxane receptor and prostaglandin E1 and E2 preferentially stimulated the relaxation-mediating receptor, whereas prostaglandin F2 alpha appeared to be active at both receptor sites.     

Hip fractures in urban population in Finland.

We studied prospectively the occurrence of hip fractures among the over 49-year-old urban populations (n = 88,206) in the cities Tampere, Jyv?skyl? and Kotka in 1989 and compared the results with a parallel Scandinavian multicentre study. During 1989, there were 266 inhabitants who were treated for a hip fracture, 213 of them were women. Women had in 132 cases a femoral neck fracture and in 81 cases a trochanteric fracture, and the corresponding numbers for men were 22 and 31. Among women, the total hip fracture incidence in Jyv?skyl? (n = 22) was the lowest when compared with the ones in Tampere (n = 47) and Kotka (n = 36). These incidences were on average lower than in the other Scandinavian cities studied in parallel. The all over ratio of femoral neck/trochanteric fractures was 1.1 in Tampere, 3.0 in Jyv?skyl? and 2.2 in Kotka and in Tampere, women had 9.3 times more femoral neck fractures than men. Our study showed that in Finland in three major cities the hip fracture incidence was lower than what has been similarly registered in corresponding urban populations in other Scandinavian countries. We also point out that the relative part of trochanteric fractures appears to be increasing.