Biomedical subjects

Barry A Kogan

Publications and source records attributed to Barry A Kogan.

12 recordsLinked to original sources

PubMed2004

A computer model to predict the outcome and duration of ureteral or renal calculous passage.

PURPOSE: We developed a computer model to predict the outcome and the duration until passage of ureteral/renal calculi. MATERIALS AND METHODS: A retrospective, randomized study was performed of the outcome in 301 patients presenting to the emergency room for renal colic. Presenting characteristics of those diagnosed with a single calculus by computerized tomography were recorded for analysis. Predictors of stone passage and passage duration were identified and then used to create a logistic regression model. The algorithm was trained on 141 randomly selected patients and then tested on a separate 160 patients. Model accuracy was compared to predictions from 10 experienced urologists and 9 urology residents in 77 randomly selected patients. The model was tested further in 30 randomly selected patients at a private hospital to assess its general applicability. RESULTS: The model prediction accuracy in 160 patients was 86.3% for passage and 87.3% for duration (less or greater than 2 weeks). In the comparison group the model, the 10 experienced urologists and the 9 urology residents had an overall prediction accuracy of 88.3%, 70.5% (p = 0.006) and 72% (p = 0.007) for passage, and 87.1%, 71.6% (p = 0.007) and 81% (p = 0.075) for duration, respectively. Prediction accuracy was 93.3% for passage and 90.3% for duration when tested at a private hospital. CONCLUSIONS: Our model provides outcome and duration of passage predictions for patients presenting acutely in the emergency room with a single ureteral/renal calculus. It performs better than experienced urologists and urology residents. It can be applied to a private practice setting with equal accuracy.

Adolescent↗

PubMed2004

Impact of urinary incontinence on self-concept in children with spina bifida.

PURPOSE: Low self-concept and self-esteem are thought to be the main predictors of psychological problems in children and adolescents. Children with spina bifida are thought to be at an increased risk for low self-concept and self-esteem given their disabilities. We examined the impact of urinary continence on self-concept in children with myelomeningocele. MATERIALS AND METHODS: A total of 50 patients 7 to 19 years old with spina bifida were evaluated using the Hartner self-perception profile. Each patient was asked to self-rate on a scale of 1 to 4 using specific domains of self-concept, including scholastic competence, social acceptance, athletic competence, physical appearance, behavioral conduct and global self-worth. Continence and several other factors, namely ambulatory status, family situation and insurance status, were reviewed simultaneously. RESULTS: There were no statistically significant differences between continent patients with spina bifida and controls. Overall children with spina bifida rated lower in scholastic competence, social acceptance and behavioral conduct than controls. Girls with spina bifida scored lower in perceived athleticism, physical appearance and global self-worth than boys with spina bifida. Continent girls were self-rated higher in social acceptance and global self-worth than incontinent girls. Continent boys were self-rated higher in scholastic competence, social acceptance, physical appearance and behavior compared to incontinent boys. CONCLUSIONS: Continence is associated with better self-concept in children with spina bifida and incontinent girls are at particularly high risk for poor self-esteem. Urologists' efforts to promote continence are likely to have a positive effect on self-concept in boys and girls with spina bifida.

Adolescent↗

PubMed2004

Recurrence risk in infants with urinary tract infections and a negative radiographic evaluation.

PURPOSE: Infants with urinary tract infections (UTI) and no abnormality on radiological evaluation are usually discharged from urological followup but the natural history of these children is unknown. We evaluate the rate of and potential risk factors for UTI recurrence in this specific population. MATERIALS AND METHODS: We reviewed retrospectively charts of children evaluated for first UTI before age 6 months between January 1996 and February 2001. Only patients with a normal ultrasound and voiding cystourethrogram were included in this study. A telephone questionnaire was administered to the parents, which inquired about the UTI, duration of breast-feeding, type of formula, family history of UTI, neurological problems, history of constipation or recurrent fevers, as well as social status. Chi-square test was performed for statistical analysis. RESULTS: We identified 264 children with UTIs, of whom 119 (45%) had a negative ultrasound and voiding cystourethrogram. Followup was available on 68 girls (81%) and 16 boys (19%) of the 119 children (71%). Of the 84 children 16 (19%) had recurrent UTI. Mean followup was 4.4 years (range 1.9 to 7.0). No factors had a statistically significant correlation for UTI recurrence. The p value for gender and history of undiagnosed fevers was 0.077 and 0.082, respectively. CONCLUSIONS: About 20% of children will have recurrent UTIs despite negative radiological evaluation. Although not statistically significant, there was a trend for an increased risk in girls and those with recurrent febrile illnesses. History of daytime dryness and/or constipation was not predictive of recurrent UTIs in our series.

Child↗

PubMed2003

Structural and vascular response of normal and obstructed rabbit whole bladders to distension.

OBJECTIVES: To investigate the structural and morphologic effect of distension after partial outlet obstruction in rabbits. METHODS: Thirty male New Zealand white rabbits were separated into two groups: control (sham) and partial outlet obstruction (3 weeks). Three rabbits from each group were distended to 5%, 25%, 50%, 100%, and 125% of capacity. Each bladder was fixed at the volume in buffered formalin for 6 to 8 hours. Sections of dorsal and ventral bladder were blocked, and cross sections were evaluated. Quantitative morphometry was performed, and CD31 immunohistochemistry was used to characterize the vascularity. RESULTS: Partial outlet obstruction resulted in increased bladder weight and capacity and increased thickness of the mucosa, submucosa, detrusor, and serosa. In the control bladder, the greatest thinning was seen between 5% and 25% capacity, and in the obstructed group, the greatest thinning occurred between 25% and 50%. The level of vascular collapse was significantly greater for the control bladders than for the obstructed bladders at all levels of distension. Finally, the obstructed bladders showed a significantly greater level of vascularity in the submucosa than the control bladders. CONCLUSIONS: Normal bladder distension resulted in significant morphologic changes when the bladder was distended to 25% of capacity but changed relatively little between 25% and 125%. However, distension of the obstructed bladder resulted in significant morphologic changes when the bladder was distended from 25% to 50% of capacity but changed relatively little between 50% and 125%.

Animals↗

PubMed2003

Follow-up and management of recurrent Wilms' tumor.

Over the past 3 decades, enormous advances have been made in the creation of a standardized treatment protocol for Wilms' tumor. Less morbid regimens for low-risk patients and more efficacious aggressive treatment protocols for high-risk patients have been developed, and continue to be improved with newer studies, such as the NWTS-V. An area that has posed a more challenging aspect of the disease is its relapse. Although a standard follow-up protocol has been produced by in-depth evaluation of previous works, there has been a great deal of difficulty demonstrating improved relapse-free and overall survival rates in re-treatment of children suffering from recurrent Wilms' tumor. Several factors are involved in the success of treatment of relapse, some of which include prerelapse treatment of initial disease and stage, site, and timing of recurrence. New agents and their combination with chemotherapeutics that already have established efficacy are being used for treatment of Wilms' tumor relapse, with varying success. These studies should lead the way for newer investigations in the future. Patients with anaplastic disease, rhabdoid tumors, and clear cell sarcoma are especially in need of these future investigations. Perhaps the true final frontier is establishing the likelihood of patients suffering a relapse. This topic currently is being studied in the fields of biologic markers and gene expression. This knowledge will hopefully, in turn, tailor initial treatment in a more specific manner.

Adult↗

PubMed2003

Response of the fetal sheep bladder to urinary diversion.

PURPOSE: In adults urinary diversion results in bladder atrophy and a rapid decrease in contractile function. Little is known about the effects of urinary diversion on bladder development. In this regard we characterized the responses of fetal sheep bladder strips obtained from animals that underwent urinary diversion. MATERIALS AND METHODS: Urinary diversion was performed on fetal sheep after 90 days of gestation (term 147 days) and bladder tissue was obtained 2 weeks later. Contractile and relaxant responses of full-thickness bladder strips were tested. RESULTS: Bladders from fetal sheep subjected to urinary diversion weighed significantly less than control fetal bladders. Histological studies demonstrated marked connective tissue infiltration and the reorganization of smooth muscle elements. Carbachol stimulated a tonic contraction, while field stimulation administered during the tonic contraction elicited a phasic relaxation or a biphasic response, consisting of an initial relaxation and then a phasic contraction in control and diverted bladders. Contractile responses of defunctionalized strips to carbachol were significantly less than those of control bladder strips. Contractile responses of defunctionalized bladder strips to field stimulation at 1 Hz. were significantly greater than those of control strips. Responses of the 2 sets of fetal bladder strips to higher frequencies were similar, as were the contractile responses to adenosine triphosphate and KCl. Field stimulated relaxations in the presence of carbachol stimulated contraction of defunctionalized bladder strips were significantly greater than those of control strips, while the relaxant responses of each set of fetal bladder strips to isoproterenol and nitroprusside were similar. CONCLUSIONS: Urinary diversion in normal fetal sheep resulted in marked structural changes, reduced carbachol stimulation and increased field stimulation relaxation.

Animals↗

PubMed2003

Neural network using combined urine nuclear matrix protein-22, monocyte chemoattractant protein-1 and urinary intercellular adhesion molecule-1 to detect bladder cancer.

PURPOSE: We developed a neural network to identify patients with bladder cancer more effectively than hematuria and cytology. The algorithm is based on combined urine levels of nuclear matrix protein-22, monocyte chemoattractant protein-1 and urinary intercellular adhesion molecule-1. MATERIALS AND METHODS: A randomized double-blinded study of voided urine from 253 patients undergoing outpatient cystoscopy was performed. Of the patients 27 had bladder cancer on biopsy and 5 had muscle invasion. Urine tumor markers were measured using sandwich-enzyme-linked immunosorbent assay kits. Urine from patients with bladder cancer on cystoscopy was compared to urine from controls with negative cystoscopy results. An algorithm was created with 3 sets of cutoff values modeled to be 100% sensitive for superficial bladder cancer, 100% specific for superficial cancer and 100% specific for muscle invasive cancer, respectively. We compared our model to hematuria and cytology. RESULTS: For the hematuria dipstick test sensitivity, specificity, positive and negative predictive values were 92.6%, 51.8%, 18.7% and 98.2%, respectively. For atypical cytology sensitivity, specificity, positive and negative predictive values were 66.7%, 81%, 29.5% and 95.3%, respectively. For the sensitive model set sensitivity, specificity, positive and negative predictive values were 100%, 75.7%, 32.9% and 100%, respectively. For the specific model set sensitivity, specificity, positive and negative predictive values were 22.2%, 100%, 100% and 91.5%, respectively. For the muscle invasive model set sensitivity, specificity, positive and negative predictive values were 80%, 100%, 100% and 99.6%, respectively. The standard bladder tumor evaluation of 253 patients costs 61,054 US dollars but 36,450 US dollars using our model. CONCLUSIONS: Our algorithm is superior to conventional screening tests for bladder cancer. The model identifies patients who require cystoscopy, those with bladder cancer and those with muscle invasive disease. It provides possible savings over current screening methods. The potential loss of other information by not performing cystoscopy was not evaluated in our study.

Adolescent↗

PubMed2003

Reperfusion injury of the rat bladder is worse than ischemia.

PURPOSE: Previous studies have demonstrated that in vivo and in vitro ischemia of the bladder results in decreased contractile responses. However, to our knowledge the effect of reperfusion following ischemia of the bladder is not known. MATERIALS AND METHODS: Adult male rats were subjected to bilateral bladder ischemia and varying periods of reperfusion. In vivo ischemia was created for 4 hours by reversibly clamping the 2 vesical arteries for 4 hours. Reperfusion was produced by removing the clamps and allowing the animals to recover for 1 day, 1 week or 1 month after surgery. Following recovery bladders strips were studied using field stimulation (FS), carbachol and KCl. The maximal contractile response and rate of response generated were recorded digitally and analyzed. RESULTS: The maximal responses to FS, carbachol and adenosine triphosphate (ATP) were not decreased by 4-hour ischemia alone, whereas the response to KCl was decreased significantly. The contractile responses to FS and KCl were significantly decreased after 1 day and 1 week of reperfusion. Responses after 1 month of reperfusion were increased significantly compared with responses after 1 week of reperfusion. The responses to ATP were not affected by ischemia or reperfusion. The contractile response to KCl was significantly more sensitive to ischemia than the responses to carbachol, ATP or FS, whereas the contractile response to FS was significantly more sensitive to reperfusion than the other forms of stimulation. CONCLUSIONS: This study demonstrates clearly that injury by reperfusion following ischemia is more detrimental than the effects of ischemia alone and FS contraction is the most sensitive form of stimulation to reperfusion damage. This study also demonstrates the ability of the bladder to recover from ischemic and reperfusion injuries.

Adaptation, Physiological↗

PubMed2002

The functional and structural response to distention of the rabbit whole bladder in vitro.

PURPOSE: We investigated the effects of distention on intravesical pressure generation in response to stimuli in relation to its effects on bladder wall thickness and morphology. MATERIALS AND METHODS: A total of 25 New Zealand White rabbits were separated into 5 groups of 5 each. Each in vitro whole bladder preparation was filled with saline to 5% (undistended), 25%, 50%, 100% or 125% capacity (60 ml.). The effects of field stimulation, adenosine 5'-triphosphate, carbamylcholine chloride (carbachol) and KCl on intravesical pressure generation were determined. Additional bladders were similarly distended (3 at each percent of capacity), fixed in formalin and evaluated by semiquantitative morphometry. RESULTS: Pressure generation in response to field stimulation was maximal at 5% of capacity and it decreased progressively thereafter. Compared with the responses of undistended bladders, at 25% capacity the response to carbachol increased and then decreased progressively above 25%. Distention had no significant effect on the response to KCl. Interestingly pressure generation in response to adenosine 5'-triphosphate was increased more than 4-fold at 25% bladder capacity compared with 5% and it did not change significantly thereafter. Bladder wall thickness was decreased more than 50% at 25% capacity and by an additional 12% at 125% capacity. The greatest thinning was observed in the mucosa compared with the submucosa and muscularis. CONCLUSIONS: Bladder distention significantly reduced pressure generation in response to field stimulation only, indicating that distention reduced the effectiveness of synaptic transmission without altering muscarinic receptor function or membrane depolarization. The greatest change (decrease) in the response to field stimulation occurred between 5% (undistended) and 25% capacity, which was the change in distention that most affected bladder wall thinning.

Adenosine Triphosphate↗

PubMed2002

Stented versus nonstented pediatric pyeloplasty: a modern series and review of the literature.

PURPOSE: Dismembered pyeloplasty remains the principal surgical therapy for pediatric ureteropelvic junction obstruction, although the method of postoperative drainage continues to be debated. We compared stented versus nonstented repairs in a modern series. MATERIALS AND METHODS: We evaluated 117 pediatric dismembered pyeloplasties performed by 3 pediatric urologists at 2 institutions from 1991 to 2000. Hospital stay, success rate and complication rate were reviewed. Results were compared with 833 evaluable cases in the literature. RESULTS: Of the 52 stented repairs urological complications developed in 6 (12%), including symptomatic urinary tract infection in 3 and temporary obstruction in 3. Of the 65 nonstented repairs urological complications developed in 10 (15%), including prolonged leakage in 3, urinoma in 3, obstruction in 3 and urinary tract infection in 1. Mean hospitalization plus or minus standard error was shorter in the stented group (2.1 +/- 0.89 versus 2.6 +/- 1.1 days, p <0.02). We identified 9 previous studies comparing a total of 339 stented with 494 nonstented repairs. Overall the number of complications was almost equal (12% versus 14%) but the stented group had more infections, whereas more leaks occurred in the nonstented group. The nonstented group required more secondary procedures (12 of 339 versus 45 of 494, p = 0.003). Hospital stay was 12 days for stented and 5 days for nonstented repair in these earlier series. CONCLUSIONS: In children the outcome of stented pyeloplasty is similar to that of nonstented repair. In contrast to previous reports, using a stent for drainage should not necessitate a longer hospital stay.

Child↗

PubMed2002

Preliminary study of the safety and efficacy of extended-release oxybutynin in children.

OBJECTIVES: To test the safety and efficacy of extended-release oxybutynin in children with bladder dysfunction. The efficacy of oxybutynin in children has been limited by side effects. A new extended-release formulation of oxybutynin has some benefits versus traditional oxybutynin but has never been evaluated in children. METHODS: A retrospective study was performed on 25 children who had been treated with extended-release oxybutynin. Fourteen had neurogenic bladder dysfunction and 11 had urinary frequency and urgency and urge incontinence but no neurologic abnormalities. Patients and families were asked to semiquantitatively (0 to 10 grading with 10 = severe) assess the effects of the medication on efficacy, as well as side effects and compliance with medication schedules. RESULTS: All 25 patients had improvement in incontinence and/or voiding dysfunction on extended-release oxybutynin. Twelve (48%) experienced no side effects. Of the 13 who did, 10 complained of dry mouth (grade 4.6 plus minus 0.5), 4 had constipation (grade 5.8 plus minus 1.8), 4 had heat intolerance (grade 5.1 plus minus 0.9), and 3 had drowsiness (grade 5.3 plus minus 2.4). Of patients previously treated with oxybutynin, the extended-release oxybutynin was equally or more efficacious and had the same or fewer side effects, especially less dry mouth. Families reported much better patient compliance with the medication regimen using extended-release oxybutynin compared with oxybutynin. Patient and family satisfaction was very high, and 21 of 25 have continued using the medication. CONCLUSIONS: Extended-release oxybutynin is safe and efficacious in children. In this preliminary evaluation, it had benefits over traditional, immediate-release oxybutynin.

Adolescent↗

PubMed2002

Conservative management in neurogenic bladder dysfunction.

PURPOSE OF REVIEW: A few decades ago, urinary diversion, usually with an ileal conduit, was the ultimate outcome for most children with spina bifida. The revolutionary institution of clean intermittent catheterization has changed the algorithm totally. Furthermore many new drugs have been developed during the past decade and have decreased the need for surgery dramatically. In this article, we will focus on the most recent data on new modalities of therapy to help avoid urinary diversion or bladder augmentation. RECENT FINDINGS: In addition to clean intermittent catheterization and oxybutynin treatment, a new generation of anticholinergic medications, such as tolterodine, has been developed. For patients who drop out because of the side-effects of oral administration, new methods of administration are now available, including extended release and intravesical instillation. For those unresponsive, botulinum-A toxin and resiniferatoxin are two relatively new drugs in the field, administered as intravesical injection and instillation, respectively. Intravesical or transdermal electrical stimulation, sacral nerve stimulation and biofeedback therapy are under development, but as currently administered, are not yet completely successful. SUMMARY: Although life-saving in many respects, bladder augmentation introduces life-long risks of its own. Our goal in describing 'conservative' management is to prevent this step. Many alternatives to surgery are available now and more effective strategies are under development.

Anti-Dyskinesia Agents↗