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Biomedical subjects

N K Bissada

Publications and source records attributed to N K Bissada.

At least 19 recordsLinked to original sources
PubMed2007

Continent cutaneous urinary diversion in children: experience with Charleston pouch I.

PURPOSE: Complete continent urinary diversion not incorporating the bladder is not commonly used in children. We evaluated the short and long-term outcome of a form of continent cutaneous urinary diversion (Charleston pouch I) in children. MATERIALS AND METHODS: A total of 17 children underwent Charleston pouch I continent cutaneous urinary diversion between 1988 and 2005. Patient records were reviewed for age, sex, indications for diversion, preoperative and postoperative laboratory and radiological studies, continence, patient and family acceptance, complications and long-term functional status. RESULTS: Patient age ranged from 6 to 16 years. The main indication for diversion was bladder exstrophy in 8 patients (47%), neurogenic bladder in 6 (35%) and cloacal abnormalities in 3 (18%). Mean followup was 87.5 months. One patient was lost to followup. With moderate fluid intake the other patients were dry with a mean catheterizing time of 3.4 hours (range 2 to 6). Catheterization intervals were adjusted for individual patients. Generally, the patients became damp or leaked if they did not catheterize at recommended intervals. Continence was achieved at variable postoperative intervals, with some patients attaining continence soon after and others at 3 to 12 months before pouch maturation. Patients irrigated the pouch a mean of 4 times weekly (range 0 to 14). Three patients (18%) had bladder stones. Ultrasound and/or other upper tract studies revealed no deterioration of the upper urinary system. No patient experienced clinical pyelonephritis or acidosis. Family and patient acceptance was satisfactory. CONCLUSIONS: Continent cutaneous urinary diversion with Charleston pouch I was satisfactory in this group of children. It provided preservation of the upper urinary tract, and achieved acceptable continence rates while allowing leakage when catheterization was not performed at recommended intervals. In addition, patient and parent acceptance was good, and complication rates were acceptable.

Adolescent↗
PubMed2003

Intermediate effects of the ileocaecal urinary reservoir (Charleston pouch 1) on serum vitamin B12 concentrations: can vitamin B12 deficiency be prevented?

OBJECTIVE: To assess the long-term effects of a form of ileocolic urinary reservoir (Charleston Pouch 1) on vitamin B12 serum levels, as vitamin B12 deficiency may be an important long-term risk after urinary diversion by this method. PATIENTS AND METHODS: The study included 60 patients (mean age 52 years, range 27-77; 33 men and 27 women) who had a follow-up of >or= 36 months (36-132 months) after the construction of an ileocaecal urinary reservoir. Vitamin B12 serum levels were determined at the time of diversion and again when the patients were evaluated every 6 months. RESULTS: Fifty-eight patients had a normal serum vitamin B12 concentration before surgery (two patients were excluded from the study because they had low levels); the mean level was 464 pg/mL (normal range 247-1000). At 6 and 12 months, the mean vitamin B12 levels were 367.5 and 468.5 pg/mL; at 1.5, 2, 3, 4, 5, 6, 7, 8, 10 and 11 years, the mean levels were 305, 495.5, 436.5, 379.5, 423.5, 393, 529.5, 631, 333.5 and 340 pg/mL, respectively. CONCLUSION: Ileocaecal urinary reservoirs have no adverse effects on serum vitamin B12 levels for up to 10 years after surgery. Patients with vitamin B12 deficiency must be identified and given adequate parenteral doses for life. Because body stores of vitamin B12 may not be depleted for many years, problems with B12 may be masked for a long time. We recommend that vitamin B12 levels be obtained annually, that a modest supplement twice yearly (by injection) may be beneficial and that serum vitamin B12 must be sampled before giving vitamin B12 injections, to avoid false results.

Adult↗
PubMed2001

Defects of DNA mismatch repair in human prostate cancer.

Loss of mismatch repair (MMR) function leads to the accumulation of errors that normally occur during DNA replication, resulting in genetic instability. Germ-line mutations of MMR genes in the patients with hereditary nonpolyposis colorectal cancer lead to inactivation of MMR protein functions, and the defects of MMR are well correlated to the high rate of microsatellite instability in their tumors. Previous studies (T. Uchida, et al. Oncogene, 10: 1019-1022, 1995; S. Egawa, et al. Cancer RES:, 55: 2418-2421, 1995; J. M. Cunningham, et al. Cancer RES:, 56: 4475-4482, 1996; X. Gao, et al. Oncogene, 9: 2999-3003, 1994; H. Rohrbach, et al. Prostate, 40: 20-27, 1999) have shown that genetic instability (chromosomal and microsatellite instability) is detectable in human prostate cancer. To elucidate the role of MMR genes in the tumorigenesis of prostate cancer, we evaluated the expression of these genes in human cancer cell lines and in tumor specimens. Using Western blot analysis, we detected loss among MSH2, MLH1, PMS2, and PMS1 proteins in DU145, LNCaP, p69SV40T, M2182, and M12 cells. In addition, genomic instability in the prostate cell lines including DU145, PC3, LNCaP, p67SV40T, M2182, and M12 was detected by a microsatellite mutation assay. Significantly, immunohistochemical analysis of prostatic tissue revealed the reduction or absence of MMR protein expression in the epithelium of prostate tumor foci compared with normal adjacent prostate tissue. In contrast to hereditary nonpolyposis colorectal cancer, characterized by defects predominantly in MLH1 and MSH2, the samples we examined showed more tumor foci with loss of PMS1 and PMS2. PMS1, which is only expressed in the basal cells in normal glands, is conspicuously absent in most prostate cancer. From these results, we conclude that there are defects of MMR genes in human prostate cancer.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Multi-institutional experience with the gastrointestinal composite reservoir.

PURPOSE: We evaluated multi-institutional experience with the gastrointestinal composite reservoir in patients with metabolic acidosis, the short bowel syndrome, severe pelvic radiation and/or renal insufficiency. MATERIALS AND METHODS: At 4 institutions 33 patients underwent construction of a gastrointestinal composite reservoir, including 19 with the short bowel syndrome, 13 with metabolic acidosis and 7 who also had renal insufficiency. A total of 16 patients underwent conversion of a previous diversion and the remaining 17 received new urinary diversion. Charts were reviewed for the metabolic impact of the gastrointestinal reservoir as well as any long-term sequelae. RESULTS: At a mean followup of 54 months there was a significant (p < or =0.05) improvement in mean preoperative and postoperative serum chloride (106 versus 102 mEq./l.), serum bicarbonate (23.3 versus 25 mEq./l.) and serum pH (7.36 versus 7.4). Mean serum creatinine did not significantly differ during followup in patients with normal renal function or renal insufficiency. Complications were not different than those of standard intestinal or gastric reservoirs. CONCLUSIONS: The gastrointestinal reservoir has provided an excellent metabolic balance in a large series of compromised patients with few side effects. We believe that the gastrointestinal composite reservoir represents the urinary diversion of choice when standard intestinal urinary reservoirs cannot be created in the setting of metabolic acidosis, the short bowel syndrome and severe pelvic radiation. However, the value of the gastrointestinal composite in the setting of renal insufficiency remains undetermined.

Acidosis↗
PubMed2001

Small cell carcinoma of the prostate: an underrecognized entity.

Adenocarcinoma is by far the most commonly diagnosed histologic subtype among prostate malignancies. Historically, there has been little awareness of the rare but lethal small cell carcinoma (SCC) in association with prostate cancer. Within the last decade, however, several reports have documented the existence of a neuroendocrine-like tumor arising from cells in the prostate. There is evidence that the development of poorly-differentiated neuroendocrine cells (similar to those found in oat cell carcinomas of the lung) can be seen in the progression of an initially pure adenocarcinoma, possibly due to the totipotential nature of the basal or reserve cells normally present in the prostatic acini. Although pure SCC is rare, admixtures of adenocarcinoma and small cell components may be more prevalent than previously believed. Since effective treatment of a prostatic tumor, or part of a tumor, with an SCC etiology differs from that of pure adenocarcinoma, early recognition of any histologic or clinical changes in the patient with prostate cancer may alter the course of the disease.

Adult↗
PubMed2000

Cystic renal masses: accurate Bosniak classification requires adequate renal CT.

OBJECTIVE: The objective of this study was to assess the practical usefulness of the Bosniak classification system for separating surgical from nonsurgical cystic renal masses in a large number of patients examined with properly performed renal CT. The study included only patients whose scans were technically adequate to allow proper assignment of the lesion to a category. MATERIALS AND METHODS: The scans of 109 patients were gathered from two large teaching institutions both prospectively and retrospectively, yielding a total of 116 analyzable renal cystic lesions. Eighty-two masses were resected from 77 of these patients, retrospectively categorized by two experienced uroradiologists using the Bosniak classification system, and correlated with pathology reports. A second group of 34 lesions in 32 patients with atypical cysts was followed up prospectively for periods ranging from 3 months to 10 years. RESULTS: The results were similar for the two institutions: 15 resected categories I and II lesions were correctly identified as benign, and all 18 category IV lesions were malignant. Twenty-nine (59%) of 49 pooled category III masses were malignant. No malignancies have been identified in the prospectively monitored group of patients. CONCLUSION: Our results are compared with earlier, smaller series and support those that show that the Bosniak classification system is useful in separating lesions requiring surgery from those that can be safely followed up, provided proper CT techniques are used.

Adolescent↗
PubMed1998

Leak point pressure use for intraoperative adjustment of the continence mechanism in patients undergoing continent cutaneous urinary diversion.

OBJECTIVES: Failure of the continence mechanism is the most common cause of unsatisfactory results and the need for revision in patients with continent cutaneous urinary diversion. We believed that incontinence in these patients could be eliminated or minimized by using the concept of leak point pressure intraoperatively to make appropriate adjustments and thus ensure adequate continence postoperatively. METHODS: The appropriate ileocolonic bowel segment for continent urinary diversion was isolated. Whenever the appendix was available, the unaltered or minimally altered appendicocolic junction was used for continence. In the absence of an appendix, the tapered distal ileum and reinforced ileocecal valve were used. Intraoperative leak point pressure (pressure at which leakage occurs) was measured before detubularization using a simple standing column manometer and arterial line tubing. Whenever leakage occurred at pressure less than 75 to 80 cm H2O, adjustment of the continence mechanism was performed and leak point pressure measurement was repeated to ensure adequate continence. RESULTS: Seventy-seven patients had long-term follow-up (30 to 100 months). These included 41 in whom the native appendix was used and 36 in whom the terminal ileum and ileocecal valves were used. Adjustment of the continence mechanism was required in 32 of the 41 patients in whom the native appendicocolic junction was used and in all 36 patients in whom the tapered ileum and ileocecal valve were used. After adjustment, all patients attained leak pressures over 80 cm H2O. At the last follow-up visit, all 77 patients were continent on intermittent catheterization every 3.5 to 6 hours. None has required revision of the continence mechanism. CONCLUSIONS: Intraoperative measurement of leak point pressure is valuable in predicting the need for adjusting the continence mechanism and eliminating or substantially minimizing the need for subsequent revision.

Follow-Up Studies↗