Biomedical subjects
Publications and source records attributed to H Behrendt.
Health effects of substances in the environment are considered from the viewpoint of cellular and molecular biology. There are nephrotoxic effects of cadmium to be discussed as well as mechanisms of carcinogenesis and neurotoxicity. Finally, the influences of noxious substances on lung clearance and immune reactions are demonstrated.
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A 12-year-old Caucasian boy developed leukemic hyphema with iris infiltration as the only relapse site during the third complete remission of his acute lymphoblastic leukemia. With high-dose methotrexate, high-dose cytosine-arabinoside plus teniposide, and a 5-week course of vincristine, prednisolone, and L-asparaginase, a complete remission could be achieved. Maintenance treatment was reinstituted for 1 year. However, after stopping the treatment, the iris infiltrate reappeared, and this time the eye was irradiated after chemotherapeutic reinduction. Seven months later, the boy remains in complete remission. The pathogenesis of leukemic iris infiltration is discussed briefly.
The DNA/cell content was measured by flow cytometry in samples obtained from 98 unselected children with acute lymphocytic leukaemia (ALL) at diagnosis. The frequency of anomalies in modal DNA content was compared to that encountered in acute childhood non-lymphocytic leukaemia (ANLL) and disseminated non-Hodgkin's lymphoma (NHL). In ALL the most frequent (35%) aberration in DNA content was an increase by 20% relative to the modal value of normal white blood cells. This subcategory, referred to as hyperdiploid ALL (HD-ALL), was characterized by a close association with the expression of the c-ALL surface marker (20/20 patients) and characteristic numerical chromosome changes, including tri- or tetrasomy of chromosome 21. Moreover, patients with hyperdiploid ALL had a much lower peripheral leucocyte count (P = 0.001) than those with diploid disease and a varying proportion of their leukaemic cells existed in the peripheral blood as morphologically normal lymphocytes expressing the c-ALL antigen. Within the standard risk category, patients with HD-ALL had a longer disease-free survival than those with diploid disease (P = 0.058). It is concluded that routine analysis by flow cytometry can conveniently and consistently detect ALL patients with hyperdiploid chromosome numbers. Hyperdiploid ALL constitutes a fairly large subtype of childhood ALL with specific biological and karyotypic properties, possibly associated with favourable prognosis.
Reference values for the differential leukocyte count using an automated cytochemical method (Hemalog D) were determined in 1216 healthy children aged 0-16 years. Log-normal distributions for the absolute counts of all the separate cell types and for the total leukocyte counts were determined. For the relative values, a log-normal distribution for the eosinophils and basophils was also established. The Hemalog D gives narrower limits compared with the manual count, but the differences between the two methods are smaller than expected. It appears that the lower limit of the separate cell types is not zero.
Histamine has generally been accepted to be an important mediator of immediate-type-allergic reactions. Histamine is released from antigen-induced sensitized mast cells and basophils. Histamine acts on its effector cells via specific H1-and H2-receptors. The stimulation of the H1-receptor type results in a contraction of smooth muscle cells of the gastrointestinal tract, the bronchioli and the large blood vessels. In addition, there are increased vascular permeability and dilation of small blood vessels. Activation of nasal exocrine glands is also due to the H1-receptor. The main effects of H2-receptor activation results in gastric acid secretion and dilation of small blood vessels. The effects of histamine are inhibited by specific H1-and H2-antagonists.
We report about the rare situation of a duplex system with double ectopia. The first diagnosis of a single ectopic ureter had to be corrected as persistent symptoms of urinary incontinence led to further investigation which finally helped to discover a second ectopic megaureter.
Ultrasound has enriched the armamentarium of the pediatric urologist. Miniprobes enable examination of preterm children without taking them out of the incubator. Special puncture needles facilitate percutaneous diagnostic procedures. A neonatal nephrostomy set was developed for temporary urinary diversion.
Chronic hypertension in children with obstructive uropathy perhaps is an infrequent, but not unimportant condition. In patients with bilateral obstruction often accompanied by urinary tract infection, hypertension may develop in spite of restoration of urinary flow. Hypertension in these patients is caused by parenchymal damage of one or both kidneys resulting as a late sequela of obstruction even after normalisation of urinary flow. This report deals with three cases of this type of obstructive uropathy and severe hypertension. Hypertension developed up to 6 years after normalisation of urinary flow. In the two patients, in who serum renin examinations were performed, high renin levels were determined peripherally (6.2-7.9 ng/ml/h) and in both kidney veins (8.5-34.7 ng/ml/h). Early diagnosis and treatment of hypertension may have important implications for the outcome of these patients. In all patients glomerular filtration rate was diminished (31.6-67.8 ml/min X 1.73 m2), in two of them further deterioration during the observation period of 3-4 years could be avoided.
Twenty-three children with equivocal uretero pelvic junction (UPJ)-obstruction underwent antegrade pressure flow studies. In three of the twelve children with upper urinary tract dilatation without vesicorenal reflux UPJ-obstruction could be excluded. Voiding cystograms showed vesicorenal reflux in eleven of the children with reflux induced hydronephrosis in seven cases. The coexistence of UPJ-obstruction and vesicorenal reflux has been noted in four children. In 23 pressure flow studies there was only one equivocal result. Twelve kidneys said to be obstructed were operated and the diagnosis was confirmed. The uneventful follow-up in the other ten children confirms the diagnosis of hydronephrosis without obstruction. The overall accuracy rate of the Whitaker-test was 96%.
Hypertension in childhood is often due to refluxnephropathy. In case of segmental lesion of the kidney hypertension may be curable by partial nephrectomy. We report on a girl with bilateral lesions and hypertension. The patient became normotensive without medication after bilateral upper pole partial nephrectomy.
From 1976 to 1983 23 boys with posterior urethral valves were seen. Two boys died during early infancy from terminal renal failure. One boy is submitted to a chronic peritoneal dialysis program. Of the remaining 20 patients ten show signs of compensated renal failure (creatinine greater than 1.5 mg/dl), ten boys show normal renal function. Four out of 46 kidneys were removed. Vesicoureteral reflux was primarily present in 14 renal units (30.4%). Three of these kidneys were removed. Reflux ceased spontaneously after valve ablation in ten renal units, ureterocystoneostomy was done in one. Ureterovesical obstruction was seen in three renal units and treated by resection and neoimplantation. Renal hypoplasia and -dysplasia together with urinary tract infections determine the degree of renal function impairment in boys with posterior urethral valves. Surgical intervention of the upper urinary tract is seldom needed. Antenatal diagnosis of obstructive uropathy is helpful to avoid septic obstruction in the neonate. Percutaneous nephrostomy is the treatment of choice in critically ill children presenting with dilatation of the upper tracts.
In all 16 boys with posterior urethral obstruction, bilateral ureteral dilatation and chronic renal failure (serum creatinine above 2 mg/dl), who were seen during the last 12 years in our departments, data about time and outcome of urological therapeutic interventions (nephrectomy, relief of bladder outflow obstruction and ureter reimplantation) were analysed retrospectively. In five patients surgical treatment was performed in our hospital, the other 11 children were referred from other hospitals. Nephrectomy of a small but not functionless kidney was performed in three of four patients without proper indication. Bladder outflow obstruction was relieved too late in five patients and insufficiently in four. 36 ureter reimplantations were performed on 24 ureters in 14 patients; reimplantation was unsuccessful in 26 ureters (72%) either because of postoperative reflux (11 ureters) or because of postoperative obstruction (15 ureters). In our opinion in boys with posterior urethral valves and bilateral ureteral dilatation ureter reimplantation should be limited to patients with proven obstruction at the uretero-vesical junction.
Macrophages of cell line IC-21 were exposed to extracts and fractions of two samples of city smog (CSE 16 and 17) from the heavy industrialized Rhine-Ruhr-area. Cytotoxic effects of extracts and fractions were analysed in various concentrations and periods of incubation. As cytotoxic parameters were determined frequencies of mitosis and pycnosis of nuclei as well as occurrence of multinucleated giant cells. An increasing dosage of noxae showed a reduction of mitotic rate, a rise of pycnosis of nuclei and of multinucleated giant cells. For both city smog extracts these effects depended on incubation period and concentration of noxae. While the global extract of city smog no. 16 was always more effective than its fractions, with city smog no. 17 the strongest alterations were demonstrable by its cyclohexane-fraction and partly by its methanol-fraction. Based on air volume of collection both samples of city smog revealed a comparable cytotoxic effect. In relation to benzo(a)pyrene-content, however, city smog no. 17 was considerable more cytotoxic than city smog no. 16. These results confirm again cytotoxicity of city smog. It can be assumed that both samples of city smog impair defense mechanisms of the lung.
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The effects of various cytostatic drug regimens on the numbers of the individual white-cell types were studied retrospectively. 131 children with solid tumors were classified into six groups according to the type of tumor. All children within the same group received similar treatment. Differential counts were performed manually, as well as with the Hemalog D. The number of lymphocytes usually decreased rapidly after initial treatment and remained at the low level throughout the period of therapy. In the majority of the children the lymphocyte count became normal between 1 and 12 months after cessation of therapy. In contrast, granulocyte and monocyte counts were not affected in some children, whereas in other children the numbers of these cell types decreased. When there was a decrease in number, the number was soon restored and, in nearly all children, before the end of therapy.
In 79 children with acute lymphoblastic leukaemia and in 18 children with disseminated non-Hodgkin's lymphoma we investigated whether the automated cytochemical differential leucocyte count (Hemalog D) gives more accurate information than the manual differential count. We concluded that the manual count is superior to the Hemalog-D count with regard to the recognition of blast cells. Furthermore, Hemalog D is not helpful for the differentiation between acute lymphoblastic leukaemia and disseminated non-Hodgkin's lymphoma.