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Biomedical subjects

M Kekomäki

Publications and source records attributed to M Kekomäki.

At least 19 recordsLinked to original sources
PubMed1992

Biodegradable fixation of distal humeral physeal fractures.

Polyglycolic acid (PGA) has been used worldwide as a biodegradable suture material since 1970. Biodegradable polyglycolide implants were introduced in osteofixation of cancellous bone fractures in 1985. From September 1987 to September 1989, 19 consecutive children with physeal fractures of the distal humerus necessitating open reduction and internal fixation were treated by transphyseal biodegradable fixation using 1.5 x 60-mm2 self-reinforced polyglycolide (SR-PGA) pins. Included were nine displaced fractures of the lateral humeral condyle, five severe avulsions of the medial epicondyle of the humerus, four displaced fractures of the humeral capitellum, and one intraarticular fracture of the medial condyle of the humerus. After accurate reduction, two smooth Kirschner pins 1.5 mm in diameter were introduced across the growth plate for temporary fixation. The metallic pins then were removed one by one and subsequently replaced with the cylindrical SR-PGA pins 1.5 mm in diameter. After operation, a padded plaster splint was worn for four weeks. Neither secondary displacement nor signs of growth disturbance were seen during the 26-month follow-up time (mean, 17.2 months). Not only the reduction of the costs but also the psychological aspects should be considered when dealing with biodegradable fixation of physeal fractures in children. Transphyseal biodegradable fixation has established itself as a procedure of choice for handling simple physeal fractures.

Adolescent↗
PubMed1990

Detection of significant vesico-ureteric reflux by ultrasound in infants and children.

We evaluated real-time ultrasonography in the diagnosis of vesico-ureteric reflux by comparing its findings to those of dynamic micturition cystourethrography. The study material comprised 124 consecutive infants and children referred to uroradiological workup, usually because of a relapsing febrile urinary tract infection. Both examinations were done during the same session. Consistent findings were obtained on 232 ureters, of which 37 displayed II. and 19 III. + reflux. II. reflux was found in 12 ureters by cystography only; thus one-fourth of low-grade refluxes escaped the diagnosis by ultrasound. The false negative findings of ultrasound examination included also two ureters showing III. reflux in cystography. As calculated for therapy-requiring (grade III or higher) reflux, the sensitivity of ultrasound was 90 per cent and its specificity 100 per cent. We conclude that ultrasound can be used as a primary diagnostic technique for girls, and in the follow-up of both boys and girls.

Child↗
PubMed1989

Correlates of diuretic renography in experimental hydronephrosis.

We studied the correlations between diuretic renographs and kidney function in experimental hydronephrosis in rabbits. Features of furosemide-stimulated 99mTc-diethylenetriamine-pentaacetic acid renographs were compared to the growth rate, thirst test and endogenous creatinine clearance rate in a chronic solitary-kidney animal model. Intravenous pyelograms, done four weeks after laparotomy, left nephrectomy, bladder resection and constriction of the right pyeloureteric junction, showed signs of obstruction in all the 12 animals of the experimental group. An absent tracer washout after intravenous furosemide, found in five animals, was associated with retarded growth, isosthenuria and an abnormal creatinine clearance. In all of the other seven animals, a distinct tracer washout after intravenous furosemide was accompanied with a normal growth rate and creatinine clearance. However, no one of these seven animals had a normal ability to retain water and concentrate urine in the thirst test. We conclude that, in this experimental model, a furosemide-induced tracer washout from the kidney pelvis cannot be taken as a proof of the absence of any upper urinary tract obstruction.

Animals↗
PubMed1989

Renal excretion of prostanoids and cyclic AMP in chronic partial ureteral obstruction of the rabbit.

The renal excretion of prostaglandins E2 and 6-keto-F1 alpha, thromboxane B2 and cyclic adenosine 3', 5'-monophosphate was measured in a solitary kidney model of chronic ureteral obstruction in rabbits. The presence of obstruction was confirmed by intravenous pyelography. Growth rate of the animals and furosemide-stimulated diethylenetriaminepentaacetic acid renography were used to grade the obstruction. As correlated to urinary creatinine concentration the excretion of 6-keto-PGF1 alpha dominated in nephrectomized, unobstructed control animals. With the degree of ureteral obstruction becoming more severe, the output of PGE2 increased, while that of 6-keto-PGF1 alpha and TxB2 decreased. As a result the ratios PGE2/6-keto-PGF1 alpha and PGE2/TxB2 were three times as high in severely obstructed rabbits as in control animals. The renal output of cyclic AMP was unaffected by chronic obstruction. We conclude that the renal metabolism of prostanoids is affected in a unique way in chronic partial obstruction of the ureter.

6-Ketoprostaglandin F1 alpha↗
PubMed1988

Fractional excretion of magnesium and renal concentrating capacity in refluxing renal units.

To evaluate renal function in kidney units exposed to vesicoureteral reflux we quantified the fractional renal excretion of magnesium and the maximal renal concentrating capacity in 22 renal units of infants and children who presented with grade III to V vesicoureteral reflux on standard voiding cystourethrography. The lowest normal value for maximal concentrating capacity and the highest normal value for fractional excretion of magnesium were set at 800 mOsm. per kg. and 8 per cent, respectively. Concentrating capacity was abnormal in all 22 renal units and the excretion of magnesium was abnormal in 5. Failure of a renal unit to retain magnesium normally was always associated with an inability to concentrate urine. We conclude that in cases of vesicoureteral reflux function of the distal part of the nephron is the first to become abnormal and concentrating capacity is a more sensitive indication of dysfunction than fractional excretion of magnesium.

Adolescent↗
PubMed1988

Binding characteristics of Escherichia coli adhesins in human urinary bladder.

We studied domains in the human bladder that acted as receptors for Escherichia coli P, S, type 1, type 1C, and O75X fimbriae or adhesin and domains in the human kidneys that were receptors for E. coli type 1C fimbriae. Binding sites in frozen tissue sections were localized by direct staining with fluorochrome-labeled recombinant strains and by indirect immunofluorescence with the purified adhesins. In the bladder, the P and S fimbriae showed closely similar binding to the epithelial and muscular layers, and the S fimbriae also bound to the connective tissue elements. Type 1 fimbriae bound to vascular walls and to muscle cells, whereas the O75X adhesin bound avidly to connective tissue elements and to some extent to epithelial and muscle cells of the bladder. The type 1C fimbriae bound to distal tubules and collecting ducts of the kidney and to vascular endothelial cells in both the kidney and bladder. The binding of all adhesin types was inhibited by specific receptor analogs or Fab fragments. The results reveal a possible mechanism by which the type 1C fimbriae may help invasion of E. coli in the kidneys but do not support a pathogenetic role for type 1 fimbriae. Similar tissue specificity of P and S fimbriae in the human urinary tract indicates that the presence of binding sites on uroepithelia does not fully explain the virulence properties of P fimbriae in human urinary tract infections.

Adhesins, Escherichia coli↗
PubMed1986

Kidney growth after pyeloplasty in childhood.

The postoperative increase of the renal parenchyma, measured with planimetry on repeated urography films, was studied in 24 infants and children. All patients had been operated on because of unilateral stenosis of the pelvioureteral junction. When the results were analyzed in a pair-control manner the paired members were almost identical for age at operation, affected side, sex, presenting clinical sign and length of followup. The 12 patients who underwent a dismembered pyeloplasty displayed a significantly stronger mean catch-up growth of the relative parenchymal area than the 12 patients who underwent a nondismembered technique. Speculatively, this difference may reflect in part the protection of the growing renal parenchyma by the preoperatively compliant and wide renal pelvis, which had led to resection and dismembered correction.

Child↗
PubMed1986

Effect of carbonic anhydrase inhibition on (U-B)pCO2 in the alkaline urine of the rabbit.

We studied factors influencing urine pCO2 minus blood pCO2 [(U-B)pCO2] in rabbits infused with sodium bicarbonate solutions. Unlike other species, the rabbit does not develop a significant (U-B)pCO2 (urine pCO2 greater than blood pCO2) after alkali or acid buffer infusion. However, intravenous acetazolamide immediately induced a significant (U-B)pCO2. The effect could not be related to the blood pH or pCO2, the urinary concentration of bicarbonate or inorganic phosphate, or to changes in plasma potassium concentration. Methazolamide was also effective in increasing (U-B)pCO2. This significant (U-B)pCO2 was present after carbonic anhydrase inhibition in rabbits subjected to chronic partial obstruction of urinary flow and in rabbits treated with 11-desoxycorticosterone acetate (DOCA). We propose that carbon dioxide is normally dissipated from the alkaline urine of the rabbit by a distal tubular mechanism, which involves catalytic conversion of carbon dioxide to bicarbonate. Inhibition of carbonic anhydrase leads to the formation of a significant (U-B)pCO2. In the rabbit, pCO2 may be an index of collecting duct acidification under certain circumstances; however, the relation of collecting duct acidification to the high (U-B)pCO2 during the inhibition of carbonic anhydrase remains to be determined.

Acetazolamide↗
PubMed1985

Malignant rhabdoid tumor of the prostatic region. Immunohistological and ultrastructural evidence for epithelial origin.

We describe a malignant rhabdoid tumour of the prostatic region in a 14-year old boy. The tumour showed positive immunoreactivity for epidermal prekeratin, monoclonal cytokeratin, epithelial membrane antigen, carcinoembryonic antigen and monoclonal vimentin but was negative for myoglobin, alfa-fetoprotein and lysozyme. Electron microscopy revealed pleomorphic cells with collections of paranuclear intermediate filaments, sheaves of tonofilaments and abundant microvilli in some tumour cells. Epithelial derivation was also suggested by occasional intracytoplasmic lumina and rare cell junctions.

Adolescent↗
PubMed1985

The growing rabbit with a solitary, partially-obstructed kidney. Analysis of an experimental model with reference to the renal concentrating ability.

The systemic and renal effects of high partial ureteral obstruction were investigated in a new model of experimental hydronephrosis. The test group comprised 12 contralaterally nephrectomized growing male New Zealand rabbits. As compared to the pyelographic findings in 6 unilaterally nephrectomized control animals, the test group could be divided into partially obstructed but non-hydronephrotic and obstructed-hydronephrotic subgroups. Animals of all 3 groups were capable of increasing their weight during the first 2 postoperative months. The mean plasma creatinine concentration remained normal in the obstructed group and even hydronephrosis was compatible with a normal serum creatinine level. As studied during forced hypotonic expansion, the renal response to a vasopressin analogue was significantly different in all 3 animal groups. Reciprocal but less marked differences were noted in the animals' ability to retain water during this test. We conclude that in this experimental model the magnitude of the antidiuretic response is inversely related to the radiologically defined degree of obstruction.

Animals↗
PubMed1979

Diagnosis of Hirschsprung's disease.

A prospective study of the accuracy of various diagnostic methods used in the detection of Hirschsprung's disease (syn. congenital intestinal aganglionosis, CIA) in 60 consecutive infants and children was done during the period 1972--76. Every patient underwent a barium enema, a rectal mucosal biopsy, which was prepared for both the demonstration of ganglia and for the assessment of acetylcholinesterase activity (ACE), and anal manometry was performed. In evaluating the clinical history, special emphasis was placed on signs of neonatal ileus. In the group of 10 patients with a definite diagnosis of CIA the results were almost uniform. In the 'non-CIA' group the search for ganglia in biopsy material proved non-confirmatory in nearly half of the cases studied due to the fact that specimens were taken too superficially. The findings pertaining to ACE, barium enema and the results of manometry were at variance or inconclusive of a final diagnosis in 10, 16 and 22% of the performed studies, respectively. The value given to neonatal history proved to be of the same order, i.e., 20% proved to be falsely positive.

Acetylcholinesterase↗