Biomedical subjects
Publications and source records attributed to K Steven.
A case of carcinosarcoma in the urinary bladder is presented. On basis of a review of the most recent literature and referring to our own case, radical cystectomy appears to be the most effective treatment of this tumour.
In 30 bladder tumor patients flexible fiberoptic and conventional cystourethroscopy was undertaken by two urologists in a random sequence. The findings at conventional cystoscopy, including histologic findings in biopsy and operative specimens, were taken to represent the true pathologic condition. Concordance was found in all but three patients, with solitary superficial grade II bladder tumors less than 2 mm in diameter that were overlooked at flexible cystoscopy. No discordance was observed in the evaluation of grade III or invasive bladder tumors. Flexible fiberoptic cystourethroscopy with urine cytology is recommended 1) as a follow-up investigation under local anesthesia in patients with non invasive bladder tumors and negative random biopsies, and 2) as a diagnostic procedure in poor-risk patients as an alternative to transabdominal ultrasonography.
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Micropuncture studies were made on insulin-treated streptozotocin diabetic rats two weeks after the induction of diabetes and on age-matched control rats. Kidney size, GFR and single nephron GFR were higher in poorly controlled diabetic rats than in normal animals. Single nephron GFR rose as a result of an increase in the hydraulic pressure difference across the glomerular capillary wall caused mainly by a rise in the glomerular capillary pressure due to a diminished ratio of afferent to efferent arteriolar hydraulic resistances. Furthermore, the intratubular pressure was reduced as a result of a decrease in hydraulic resistance in the loop of Henle. Strict metabolic control prevented these changes. In conclusion, the increase in renal function in experimental diabetes is determined by the degree of metabolic control excluding a potential nephrotoxic effect of streptozotocin per se.
Urethral closure pressure was recorded in four patients during sleep in order to determine the pathogenesis of nocturnal incontinence after radical cystectomy and ileocaecal bladder replacement. The sleep stages were determined by electroencephalography. The resting pressure in the intestinal bladder was low and increased only slightly during filling. The maximum urethral pressure decreased during sleep but the urethral closure pressure remained positive when the intestinal bladder was not contracting. The peristaltic contractions in the intestinal bladder continued during sleep, causing incontinence. The nocturnal incontinence is probably a result of the reduced level of consciousness that makes it impossible to increase the tone of the external urethral sphincter during contractions of the intestinal bladder.
Urologic surgery was necessitated by complications following radiotherapy for gynecologic cancer in 17 patients. Four had recurrent malignant disease and 13 were without evidence of malignancy. The median interval to onset of the urologic complications was 18 (range 0-144) months. Ileal substitution was performed because of bilateral ureteral obstruction in two cases, and transureteroureterostomy for unilateral obstruction in one case. Vesicovaginal fistula was present in 14 patients, who underwent urinary diversion--cutaneous ureterostomy and ligation of the other ureter (6 cases), cutaneous ureterostomy and transureteroureterostomy (3) and ileal conduit diversion (5). The immediate morbidity and mortality were determined by the patients' general state of health rather than by presence or absence of recurrent malignant disease. The choice of diversion procedure should be guided by the patient's fitness, the status regarding recurrence of malignancy and the distribution of function between the two kidneys.
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Radical cystectomy was modified by leaving the apical prostatic capsule to facilitate anastomosis of the isolated ileocecal segment to the urethra and to preserve erectile potency. The transpubic approach was used to increase the exposure, and to facilitate dissection and anastomosis. A total of 15 patients with stages T1 to T4 bladder tumors underwent the operation: 13 after preoperative radiotherapy with 4,000 rad and 2 had salvage cystectomy after 6,000 rad. One patient died postoperatively. The remaining 14 patients underwent urodynamic evaluation 3 to 6 months postoperatively. The maximum urine flow rates were almost normal and none of the patients had significant residual urine. Daytime urinary continence was satisfactory in 13 patients and 1 was moderately incontinent. All of the patients were incontinent at night, probably owing to peristaltic contractions in the intestinal bladder and relaxation of the pelvic floor muscles. Preoperatively, 8 patients experienced erections and 7 had intercourse. Postoperatively, erectile potency was preserved in 4 patients and 3 had sexual function. No orthopedic disability occurred postoperatively. The median followup was 20 months, with a range of 3 to 30 months. There have been no local recurrences. A year postoperatively 6 of 9 patients had sterile urine. This technique makes it possible to avoid a urinary stoma, to obtain satisfactory voiding and urinary continence in almost all cases, and to preserve sexual function in some patients after cystectomy.
The glomerular hemodynamics were studied in streptozotocin diabetic rats 3 months after the induction and in age-matched normal animals. Indomethacin infusion failed to cause changes in glomerular hemodynamics in normal rats but produced striking effects in the diabetic rats: The afferent arteriolar hydraulic resistance increased substantially while the efferent resistance rose moderately causing large reductions in single nephron blood flow and in the hydraulic pressure in the glomerular capillaries. Consequently, single nephron glomerular filtration rate (SNGFR) was reduced significantly below normal. The ultrafiltration coefficient of the glomerular membrane was significantly lower in the diabetic than in the normal animals (2.8 versus 5.0 nl min-1 mm Hg-1) and remained unchanged during indomethacin infusion. Our results suggest that the prostaglandin system compensates for the changes in the glomerular hemodynamics induced by diabetes by reducing the arteriolar resistances to increase the glomerular capillary pressure making it possible to maintain normal values of SNGFR and nephron blood flow.
Combining the bladder-psoas hitch Boari-flap technique makes it possible to replace the entire ureter. The operation was used successfully in one patient with an extensive proximal ureter lesion. This method can be used in patients with reduced renal function, since the continuity of the urinary tract is preserved; it requires a normal bladder wall and bladder capacity exceeding 400 ml.
Highly purified recombinant human interleukin 2 induced cytotoxicity of lymphocytes from urinary bladder carcinoma patients and from control healthy donors when added during an 18-h 51Cr microcytotoxicity assay against bladder carcinoma (T24) target cells. Similar levels of killer cell activation were detected in mononuclear cell preparations from bladder carcinoma patients and control healthy donors; hence, no defect in the responsiveness of bladder carcinoma patients' lymphocytes to interleukin 2 could be observed. The effect of the recombinant interleukin 2 was dose-dependent. Addition of monoclonal antibody 7E9 directed against cell-type restricted antigen associated with the T24 target cells and capable of inducing antibody-dependent cellular cytotoxicity could not increase the cytotoxicity-inducing effects of interleukin 2.
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Spontaneous and aspirated blood samples were collected from the welling points of surface efferent arterioles in the rat kidney. The amount of tubular reabsorbate in each sample was calculated from measurements of the inulin concentration in the sample and systemic arterial plasma. Both spontaneous and aspirated samples contained substantial amounts of tubular reabsorbate (4% +/- 1% and 11% +/- 1%, respectively). Accordingly, the single nephron filtration fraction values derived from measurements of albumin concentrations alone were significantly lower than those calculated considering the addition of the amount of tubular reabsorbate in each sample (0.26 +/- 0.01 vs. 0.30 +/- 0.01 and 0.25 +/- 0.01 vs. 0.34 +/- 0.01 for the spontaneous and aspirated samples, respectively). Increasing the rate of blood collection from the welling point by aspiration was associated with a significant decrease in the hydraulic pressure in the same vessel. The efferent arteriolar blood samples were therefore probably contaminated with tubular reabsorbate as a result of retrograde flow from the peritubular capillaries. It was confirmed that single nephron filtration fractions derived from hematocrit measurements were significantly higher than those based on albumin concentration measurements, supporting that the hematocrit of afferent arteriolar blood of the superficial nephrons is higher than that of systemic arterial blood.
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The concentration of spermatozoa in ejaculate from testes that had been subjected to orchidopexy during childhood was studied in semen samples taken after unilateral vasectomy of the contralateral normal testis in 4 patients. The counts were extremely low, which suggests that this operation does not improve fertility later in life. Sperm concentration is not influenced by unilateral vasectomy or by inguinal herniotomy during childhood.
Tubular compliance is the response of tubular diameter to changes in intratubular pressure [7]. Proximal tubular compliance was determined directly by measurements of tubular diameter and pressure and indirectly using a mathematical model of tubular fluid flow based on measurements of the hydraulic pressure gradients along the tubule under free flow conditions and during an induced pressure reduction at the end of the proximal tubule. The two independent methods yielded similar values for compliance. Proximal tubular compliance was found to depend upon the intratubular pressure: tubular compliance was significantly higher (P less than 0.001) when the intratubular pressure was reduced below normal (1.0 micron cm H2O-1) than when the pressure was increased above the control value (0.4 micron cm H2O-1). Almost identical compliance values were measured in sodium pentobarbital and inactin anaesthetized rats (P greater than 0.8). Intratubularpressure changes resulted in inverse changes in the diameters of the adjacent capillaries, suggesting that the peritubular capillaries are distensible structures.