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Biomedical subjects

B Aeikens

Publications and source records attributed to B Aeikens.

At least 19 recordsLinked to original sources
PubMed1987

Segmentation of microscopic cell scenes.

Different methods for the automated segmentation of microscopic cell scenes are presented with examples. The techniques discussed include edge detection by thresholding, "blob" detection by split-and-merge algorithm, global thresholding using gray-level histograms, hierarchic thresholding using color information, global thresholding using two-dimensional histograms and segmentation by "blob" labeling. Methods are more robust against insignificant changes in the scene and perform more reliably as more a priori knowledge about the scene is incorporated in the segmentation algorithm. The inclusion of both photometric and geometric a priori knowledge can result in a high level of correct segmentations, the cost of which is increased computation time.

Algorithms↗
PubMed1986

Intrascrotal metastases from renal cell carcinoma.

This is an up-to-date report about two patients suffering respectively from testicular and epididymal metastases of a renal adenocarcinoma in the condition following tumour nephrectomy in anamnesis. It is a survey on literature including the number of cases published.

Aged↗
PubMed1986

[Computed tomographic and sonographic detection of renal and perirenal changes following shockwave lithotripsy].

The finding of a major haemorrhage after lithotripsy induced us to look at 42 patients undergoing extracorporeal lithotripsy by CT and by sonography, both before and after the procedure, in order to determine the frequency of bleeding. In 37 patients, significant bleeding was found in the perirenal tract and in Gerota's capsule. There were six small sub-capsular haematomas which were not found by sonography and two extensive renal haematomas.

Adult↗
PubMed1986

Effective hydraulic permeability of the glomerular capillary wall in rats after uninephrectomy.

The effective hydraulic permeability (k) of glomerular capillaries was studied in 2-month-old Wistar rats 4 weeks after uninephrectomy in comparison to age-matched control rats. Isolated kidneys were perfused with a cell-free solution containing 5% albumin. In this preparation the rise of colloid osmotic pressure along the glomerular capillaries can be neglected because the filtration fraction is low (3%) due to high perfusion rates at normal filtration rates. Single nephron filtration rates (SNGFR) and effective filtration pressures were estimated by micropuncture to calculate the ultrafiltration coefficient (Kf). Glomerular capillary surface area was measured morphometrically to obtain k (k = Kf/S). We found that the effective hydraulic permeability in uninephrectomized rats was higher than in rats of comparable age (26.0 vs 18.0 nl/mm Hg X s X cm2). This can contribute to the adaptive rise in SNGFR after uninephrectomy.

Animals↗
PubMed1986

[In vitro sensitivity testing of human kidney tumors to cytostatic drugs with a rapid in vitro test].

We present a new modified in vitro culture assay for primary human renal cell carcinoma similar to the 'soft agar clonogenic assay'. However, the carrying out and expense of metrology are more simplified, allowing tumor-specific chemotherapeutic drug sensitivity testing under easier conditions. Twelve different samples of human renal carcinoma and one sample of a transitional cell carcinoma of the renal pelvis were tested for in vitro chemotherapy sensitivity using this modified colony-forming assay. The rate of tumor cells establishing in culture was 100%. Corresponding to clinical experience we observed a nearly complete resistance to the cytotoxic effects of standard chemotherapeutic agents at usual plasma concentrations in man. Only higher concentrated chemotherapeutic drugs showed in vitro therapeutic effects. The assay described here lasts about 7 days, which is beneficial from the clinical point of view. The modification of this in vitro chemotherapeutic drug treatment is unlimited for plasma concentration and duration of standard and experimental chemotherapeutic agents, drug combination and so on. So we have interesting scientific steps which could not have been undertaken under usual clinical-empirical conditions.

Adenocarcinoma↗
PubMed1986

[Catheter peridural anesthesia with bupivacaine-HCl and bupivacaine-CO2 during extracorporeal shock-wave lithotripsy].

The effects of 0.5% bupivacaine-CO2 and bupivacaine-HCl were tested in a prospective randomised trial on 16 patients who underwent extracorporal shock wave lithotripsy (ESWL) with epidural analgesia. A shorter time of onset of analgesia (3.75 +/- 0.51 min) and a faster distribution of analgesia were noted with bupivacaine-CO2. Hypoalgesic regions were not registered with bupivacaine-CO2 nor with bupivacaine-HCl under shock wave treatment. About thirty minutes after application of either substance a level 1 block according to Bromage was noted, which was not desirable during positioning of the patient on the hydraulic lithotriptor chair. However, toxic blood levels were not reached in either group of patients to any extent.

Anesthesia, Epidural↗
PubMed1986

Influence of cyclosporine A on adaptive hypertrophy after unilateral nephrectomy in the rat.

The functional challenge to a transplanted kidney is comparable to that of a single kidney after unilateral nephrectomy. The single kidney model was used in rats to study the influence of the immunosuppressant CyA. Using this model interference with immunological or preservation/transplantation problems can be excluded. Two month old rats were studied 4 weeks after unilateral nephrectomy. After unilateral nephrectomy the juvenile rats had been fed for 28 days with 10 or 15 mg/kg BW CyA daily. These rats were compared to intact control rats and to age-matched uni-nephrectomized rats. Single kidney weight was measured in one group. Single kidney function was measured in a second group, first in the metabolic cage and then in experiments with isolated kidneys perfused under standard conditions. The glomerular filtration coefficient Kf was measured by micropuncture techniques. Glomerular capillary surface area was estimated after perfusion fixation in order to calculate the effective hydraulic permeability k of the glomerular capillary wall (k = Kf/S). Standard allogeneic skin transplantation across the MHC barrier was used to establish that the CyA dosage used was immunosuppressive. The results showed that the single kidney mass (as a measure of tubular hypertrophy) and GFR were suppressed under the influence of CyA compared to controls. Analysis of glomerular filtration parameters in the isolated perfused kidneys on the single nephron level had the following results: a small increase of the glomerular capillary surface (morphometry) was suppressed under CyA, whereas the effective hydraulic permeability (k) increased by almost 40% whether CyA was given or not.

Adaptation, Physiological↗
PubMed1985

[Possibilities and departure points for quantitative cytologic evaluation of urothelial cells for cancer diagnosis using microscopic procedures and digital image processing].

Examination of exfoliated urothelial cells present in the urine has been shown to be useful by cytologists, but urinary cytology is not yet widely accepted for routine diagnostic purposes. The accuracy of urinary cytology is almost limited to high-grade transitional carcinoma (grade II-III), but is of limited value in the diagnosis of benign papilloma and low-grade tumors (grade I). The sensitivity of cytology would be increased from 50% to 80% by using a computer-based cytophotometric microscope, especially in differentiating grade I tumors.

Cytodiagnosis↗
PubMed1982

Investigation about the penetration depth in the normal bladder wall and tumor by local instillation of mitomycin into the urinary bladder.

The penetration depth of mitomycin into the normal urinary bladder wall and tumor was determined in 21 bladder tumor patients. Either 20 mg mitomycin/20 ml distilled water or 40 mg/40 ml distilled water was locally instilled into the bladder with a catheter after emptying it and was left for about 25-l20 min. The individual concentrations of mitomycin within the various bladder layers (epithelial, lamina propria, up to the middle of the musculature) were determined with a thin-layer cup method specially modified for these investigations. The results show a high scatter of resorption from 2 up to 442 micrograms of mitomycin/g dry weight. With this method, mitomycin could be determined in the bladder musculature.

Administration, Topical↗
PubMed1982

[Measuring of urine cells by a high resolution microscope cytophotometric system (author's transl)].

Especially bladder tumors of low malignancy (grade I) reveal minor abnormalities and therefore these tumors are often overlooked using cytological methods. Therefore, it appeared useful to examine the applicability of microscopic scanning cytophotometry to discriminate urothelial cells by objective parameters. A special combination of a Leitz MPV 2 microscope Cytophotometer and a digitizer has been built for reasons of interactive segmentation of the cell into nucleus, plasma and background. 240 cells, stained by Papanicolaou technique, have been visually classified and the computer discrimination between benign, atypical and malignant cells has been accomplished with a small error of classification, not greater than five percent.

Cytological Techniques↗
PubMed1981

[Histochemical investigations on human bladder cancer (author's transl)].

The histochemical enzyme activity of alkaline phosphatase, nonspecific esterase, 5-nucleotidase, beta-glucuronidase, glucose-6-phosphatase, succinate dehydrogenase, and glucose-6-phosphate dehydrogenase in human bladder cancer was investigated. Tumors of 84 patients, classified into grades I-III according to the WHO classification, were compared with 12 normal and 16 inflamed bladder epithelia. As a rule, loss of alkaline phosphatase activity and a decrease of nonspecific esterase activity was found in most of these tumors. The activity of beta-glucuronidase was decreased and compared with normal tissue, also the activity of 5-nucleotidase. The succinate dehydrogenase activity in tumor tissue was frequently increased, whereas glucose-6-phosphate dehydrogenase did not show any significant reaction.

5'-Nucleotidase↗
PubMed1981

[Computer-based measurements of bladder cancer urothelial cells by high-resolution microscopic-cytophotometric system (author's transl)].

Examination of exfoliated urothelial cells present in the urine has been shown to be diagnostic by many researchers, but cytology is not yet widely accepted for routine diagnostic purposes. Cytology is highly efficient in the primary diagnosis of high grade transitional carcinoma (grade II-III) but of limited value in the diagnosis of benign papilloma and low grade tumors. The sensitivity of cytology would be increased by improving the techniques of collecting cells out of urine, using highly sensitive staining techniques and by objective cytologic measuring methods. Using a computer-based cytophotometric microscope, the cytologic analysis of 26 patients with bladder tumors are represented. There is evidence that a computerized measuring system is able to detect bladder tumors with a high accuracy.

Carcinoma, Transitional Cell↗
PubMed1981

[Morphometry on the juxtaglomerular apparatus and the glomerulus of the rat (author's transl)].

The area of contact between the macula densa and the terminal vascular components, the vas afferens, the vas efferens and the mesangium (Goormaghtigh cells) of five glomeruli of the rat has been determined morphometrically using serial sections. The surface, the filtration area, the volume and the total length of the capillaries of each glomeruli has been estimated, and these data have been correlated. There is evidence, that a contact between the macula densa and the mesangium always exists, a contact to the vas afferens is not obligatory.

Animals↗
PubMed1980

[Chances of an automated prescreening test based on cytology of the urinary tract. Preliminary report based on a high-resolution system (author's transl)].

The incidence of bladder tumors has increased in the last years. Often, at the time of diagnosis the tumor has reached a stage in which a curative radical therapy is no longer possible. With the help of urinary cytology it is often possible to obtain evidence of tumors at an early stage, before clinical symptoms become evident. For this reason, urinary cytology would appear to be a reasonable screening method for tumor detection. In the framework laws concerning measures for the preventive treatment of tumors, there is no provision for the early detection of tumors of the bladder and urinary tract. As urine is easily obtainable it appears that urinary cytology could easily by integrated into such a program for early detection of tumors. The evaluation is relatively costly in man-hours and, therefore, not suitable for screening. For this reason, urothelical cells were investigated in respect to their use as a diagnostic parameter in an automated screening test. Urinary cells can be analyzed automatically, but little experience has been made in this area of research. However, it seems that automation of urinary cytology would be a step towards screening method for tumors of the bladder and urinary tract.

Cytological Techniques↗
PubMed1980

[Studies of the morphological and morphometrical changes in the rat nephron after unilateral ureteral ligation (author's transl)].

The influence of unilateral ureteral ligation in the rat nephron has been morphometrically analysed. The glomeruli show no significant differences compared with the control groups. The lumen of the tubulus rectus I increases significantly, but irregularly, after the 6th day of ureter ligation. The brush border is mostly destroyed after the 8th day. The tubulus rectus II changes only very little during this period. At the beginning of the ligation the lumen dilates, and at the end of the experiment the tubulus becomes normalised. The most important changes have been seen on the collecting tubules. As a consequence of increased intratubular pressure the lumina continuously dilate.

Animals↗