Biomedical subjects

J T Benson

Publications and source records attributed to J T Benson.

At least 19 recordsLinked to original sources

PubMed2003

Effects of IGF-I gene therapy on the injured rat pudendal nerve.

Injured nerves and their motor units may undergo enhanced recovery when exposed to recombinant human insulin-like growth factor-I (rhIGF-I). The external anal sphincter muscle in the female rat was denervated to model incontinence. The treatment-group muscle was injected with rhIGF-1 plasmid, whereas in the control group the plasmid lacked the cDNA insert and the normal group received neither surgery nor treatment. Electromyography data at 56 days post surgery indicated more reinnervation without fibrillation potentials in the treatment group (2 of 6) than in the control group (0 of 6). The histology of the regenerated axons in the pudendal nerve distal to the crush site also suggested an improved recovery in the treatment group. The number of motor neurons retrogradely labeled with horseradish peroxidase was decreased by 50% following pudendal nerve crush in both experimental groups compared to the normal group. We conclude from these preliminary results that rhIGF-I gene therapy may improve the distal recovery of structure and function.

Anal Canal↗

PubMed2001

Detrusor biopsy as a potential clinical tool.

Previous published work suggests that electron microscopic findings in bladder biopsies correlate with urodynamic diagnoses of bladder dysfunction in geriatric patients. Our goal was to determine the reproducibility of this previous work and to evaluate the use of detrusor biopsy as a clinical tool in the diagnosis and management in a urogynecology referral population. All patients underwent an initial evaluation, including history, physical examination and urodynamics. Urodynamic evaluation included uroflowmetry, provocative cystometry, instrumented voiding study, urethral profilometry, pressure-flow studies, and evaluation of postvoid residual urine. A cystoscopic-guided detrusor muscle biopsy was obtained from all patients. Each patient was assigned one of four urodynamic diagnoses: detrusor overactivity, obstructed voiding, both overactivity and obstruction, or neither. Each was given a subgroup of normal or ineffective contractility. All detrusor biopsies were evaluated by electron microscopy. Each biopsy was assigned one of four pathologic diagnoses: dysjunction, hypertrophy, both dysjunction and hypertrophy, or neither. Each was given a subgroup of the presence or absence of degeneration. All diagnoses were assigned in a double-blind fashion. All urodynamic and pathologic diagnoses were then compared to determine the percentage agreement. Twenty-six women participated, mean age 52.7 years, range 29-77. Overall agreement among diagnoses was 30% (95% CI 11%-50%). Comparison of each category revealed the following percentage agreements: detrusor overactivity/dysjunction, 52% (95% CI 32%-73%); obstructed voiding/hypertrophy, 78% (95% CI 61%-95%); ineffective contractility/degeneration, 65% (95% CI 45%-85%). The use of detrusor biopsy as a clinical tool was not supported in this population, as demonstrated by the low percentage agreement between urodynamic and pathologic diagnoses. The etiology of bladder dysfunction should be investigated by looking beyond organ-specific structural changes.

Adult↗

PubMed2001

Monitoring pudendal nerve function during labor.

BACKGROUND: To determine methodology and feasibility of pudendal nerve monitoring during labor and delivery. METHODS: With Institutional Review Board approval, 13 low-risk, singleton pregnant women were recruited. The latency and amplitude of the perineal branch of the pudendal nerve compound muscle action potential were recorded during the second stage of labor and after delivery. With the first two patients, a wire electrode was used to stimulate the pudendal nerve continuously at the ischial spine. For the remaining 11 patients, a St. Mark's electrode was used to stimulate transvaginally. Aurethral ring electrode on a 14 French foley catheter monitored the response from the urethral sphincter. All patients received prophylactic antibiotics. EXPERIENCE: Twelve patients delivered vaginally, and one by cesarean. In two patients, continuous wire stimulation showed a gradual decrease in amplitude. Changes were minimal over 15-minute intervals. Wire electrode placement was technically difficult and dislodged easily. With the remaining 11 patients, all had data available for interpretation, and of the 85 potential perineal branch of the pudendal nerve compound muscle action potentials, 53 were obtained. No patients developed cystitis. CONCLUSION: Intrapartum assessment of pudendal nerve function is feasible. Continuous wire stimulation is technically more difficult and does not provide additional information beyond that available from intermittent stimulation.

Action Potentials↗

PubMed2001

New therapeutic options for urge incontinence.

A critical evaluation of the literature published over the past year reveals several therapeutic options for urge incontinence. Basic science advances in understanding the pathophysiology of bladder instability are paramount in the development of new therapeutic options, chief of which is sacral neuromodulation. Epidemiologic studies from around the world impact the therapies and diagnosis. Therapies include hormone delivery systems, pharmaceutical, combined behavioral and drug, botulinum, surgery, magnetic stimulation, and sacral neuromodulation.

Aged↗

PubMed2000

Effects of pudendal nerve injury in the female rat.

To test a neurogenic hypothesis for external urethral sphincter (EUS) dysfunction associated with urinary incontinence, the proximal pudendal nerve was crushed in anesthetized retired breeder female rats (n = 5) and compared with a sham lesion group (n = 4). Outcome measures included concentric needle electromyograms (EMGs) from the target EUS, voiding patterns during a 2-hour dark period, and micturition data over a 24-hour period. Fast Blue (FB) was introduced to the crush site at the time of injury and Diamidino Yellow (DY) to the EUS at the time the rats were killed (3 months post-operative), when histological analysis of the nerve and urethra was also performed. EMG records indicated the EUS motor units undergo typical denervation changes followed by regeneration and recovery. Voiding patterns from the crush group show a significant increase of small urine marks in the front third of the cage. At 1-2 weeks post-op, the frequency of voids was significantly increased in the crush group compared to pre-op and late post-op time periods. The mean volume voided in the light phase at the early post-op time was significantly increased in the sham group. Light and electron microscopic patterns seen in nerve and muscle suggest the regenerating motor units maintain a structural integrity. Motoneurons in the lower lumbar cord were labeled with either DY (14. 5 +/- 6.8), FB (31.7 +/- 23.7), or both (35.0 +/- 17.5) tracers, indicating approximately 54% of the crushed pudendal neurons regenerated to the EUS. In conclusion, several measures suggest this reversible crush lesion induces mild urinary incontinence. This animal model is promising for further development of hypotheses regarding neural injury, the pathogenesis of incontinence, and strategies aimed at prevention and treatment. Neurourol. Urodynam. 19:53-69, 2000.

Animals↗

PubMed2000

Sacral nerve stimulation results may be improved by electrodiagnostic techniques.

Sacral nerve electrical stimulation (sacral neuromodulation) therapy for patients with refractory urge incontinence, frequency and urgency, and non-obstructive retention yields an effective 75%-80% success rate. Electrodes are surgically implanted if initial percutaneous stimulation testing has a successful clinical response. Unfortunately, up to 50% of patients are denied surgical implantation because of an unsuccessful response to the test stimulation. In this descriptive study, adding electrodiagnostic monitoring to the currently used biological monitoring techniques was associated with a reduction in the number of tested patients denied implantation to 20%. These findings suggest that the incorporation of electrodiagnostic techniques may improve the clinical efficacy of sacral stimulation therapy. Randomized prospective testing of this hypothesis is suggested.

Adult↗

PubMed2000

Ultrastructure of detrusor and urethral smooth muscle in women with urinary incontinence.

OBJECTIVE: We performed a quantitative study to determine whether mixed urinary incontinence was associated with any ultrastructural changes in detrusor and urethral smooth muscle. STUDY DESIGN: Detrusor and urethral smooth muscle biopsy specimens were obtained at the time of laparotomy from 5 women aged 35 to 65 years with mixed urinary incontinence and from a control group of 5 continent women. Smooth muscle morphologic characteristics were assessed from a systematic random sample of electron micrographs. A further 16 urethral biopsy specimens were similarly analyzed to confirm the findings of the initial study. RESULTS: The electron-dense portion of the sarcolemma was smaller in urethral biopsy specimens taken from patients with intrinsic sphincter deficiency than in those from control subjects (chi(2)((1)) = 4.9; P =.027). No other morphologic characteristics were unique to patients with incontinence. CONCLUSIONS: Our study suggests that focal adhesion architecture is decreased in urethral smooth muscle of patients with intrinsic sphincter deficiency.

Adult↗

PubMed2000

Correlation of intraurethral ultrasonography and needle electromyography of the urethra.

OBJECTIVE: To correlate structural intraurethral ultrasound findings with needle electromyography of striated urethral sphincters in young continent nulliparas. METHODS: Twenty-three nulliparas, each less than 35 years old and without pelvic floor disorders, were recruited at Methodist Hospital in Indianapolis, Indiana, and the University of Louisville in Louisville, Kentucky. Each had concentric needle electromyography of their urethra to localize their striated urethral sphincter. Intraurethral ultrasound was used to identify the needle tip and layer in which it was found, examine the sonographic appearance of periurethral anatomy, and measure the thickness of hypoechoic and outer hyperechoic layers. RESULTS: Three layers were seen on intraurethral ultrasound: a mildly hyperechoic inner layer, a hypoechoic middle layer, and a hyperechoic outer layer. The concentric needle tip was seen in all subjects and showed motor unit action potentials when located in the outer hyperechoic layer. The mean thickness of the hypoechoic layer was 2.5 mm, and the mean thickness of the outer hyperechoic layer was 2.6 mm. CONCLUSION: Motor unit action potentials showed that striated muscle was present in the outer hyperechoic layer on intraurethral ultrasound, implying that it contains the striated urethral sphincter.

Action Potentials↗

PubMed2000

Adaptation of the Mayo primary biliary cirrhosis natural history model for application in liver transplant candidates.

The Mayo natural history model has been used widely as a tool to estimate prognosis in patients with primary biliary cirrhosis (PBC), particularly liver transplant candidates. We present an abbreviated model in which a tabular method is used to approximate the risk score, which may be incorporated in the minimal listing criteria for liver transplant candidates. Data used in the development and validation of the original Mayo model were derived from 418 patients with well-characterized PBC. To construct an abbreviated risk score in a format similar to that of Child-Turcotte-Pugh score, 1 to 3 cut-off criteria were determined for each variable, namely age (0 point for <38, 1 for 38 to 62 and 2 for >/=63 years), bilirubin (0 point for <1, 1 for 1 to 1.7, 2 for 1.7 to 6.4, and 3 for >6.4 mg/dL), albumin (0 point for >4.1, 1 for 2.8 to 4.1, and 2 for <2.8 g/dL), prothrombin time (1 point for normal and 2 for prolonged) and edema (0 point for absent and 1 for present). The intervals between these criteria were chosen in a way to enable a meaningful classification of patients according to their risk for death. This score is highly correlated with the original risk score (r = 0.93; P <.01). The Kaplan-Meier estimate at 1 year was 90.6% in patients with a score of 6. The abbreviated risk score is a convenient method to quickly estimate the risk score in patients with PBC. An abbreviated score of 6 may be consistent with the current minimal listing criteria in liver transplant candidates.

Adult↗

PubMed2000

Urethral collagen morphologic characteristics among women with genuine stress incontinence.

OBJECTIVE: This was a study of the morphologic characteristics of urethral collagen in women with stress incontinence and continent control women. STUDY DESIGN: Urethral needle biopsy specimens were obtained from 31 women. Fifteen women were continent, and the other 16 had undergone full urogynecologic assessment for symptoms of urinary incontinence. Biopsy specimens were assessed under electron microscopy. Mean collagen fibril diameter was measured and collagen morphologic characteristics were assessed. RESULTS: The biopsy specimens from 30 women were included in the analysis. Collagen fibril diameter did not vary with continence status, the presence of pelvic organ prolapse, age, race or hormonal status. Alterations in collagen fibril morphologic characteristics were evident in the biopsy specimens from nine patients with incontinence. The alterations in collagen morphologic characteristics fell into three patterns, which for convenience were referred to as the obscured pattern, the dense pattern, and the degenerative pattern. CONCLUSION: Altered collagen morphologic characteristics are found in some patients with stress incontinence, and possible causes for those alterations are suggested by their appearances.

Adult↗

PubMed2000

Female pelvic organ prolapse: a comparison of triphasic dynamic MR imaging and triphasic fluoroscopic cystocolpoproctography.

OBJECTIVE: This study compared dynamic MR imaging with fluoroscopic cystocolpoproctography for the detection and measurement of prolapse of pelvic organs. SUBJECTS AND METHODS: Ten patients underwent triphasic dynamic MR imaging and triphasic fluoroscopic cystocolpoproctography with identical amounts of contrast material to opacify the bladder, vagina, and rectum. The dynamic MR imaging procedure included cine-loop presentation. Each examination was analyzed to determine the presence and extent of prolapse of pelvic organs based on specific measurements. RESULTS: Both dynamic MR imaging and fluoroscopic cystocolpoproctography revealed 10 rectoceles (mean extents, 2.85 and 2.45 cm, respectively). Nine cystoceles were revealed by both dynamic MR imaging (mean extent, 4.05 cm) and fluoroscopy (mean extent, 4.55 cm). Seven enteroceles were revealed, one of which was initially not seen on dynamic MR imaging. Two sigmoidoceles were revealed, one of which was not seen on fluoroscopy. The mean extent of the enteroceles and sigmoidoceles on dynamic MR imaging was 3.50 cm, and the mean extent on fluoroscopy was 4.25 cm. Nine of the 10 patients were able to defecate in the supine position on the MR imaging table. Patients were divided equally in their preference for dynamic MR imaging or fluoroscopic cystocolpoproctography. CONCLUSION: Triphasic dynamic MR imaging and triphasic fluoroscopic cystocolpoproctograpy show similar detection rates for prolapse of pelvic organs. Although dynamic MR imaging underestimates the extent of cystoceles and enteroceles, it has the advantage of revealing all pelvic organs and the pelvic floor musculature in a multiplanar cine-loop presentation.

Adult↗

PubMed2000

A revised natural history model for primary sclerosing cholangitis.

OBJECTIVE: To describe a natural history model for primary sclerosing cholangitis (PSC) that is based on routine clinical findings and test results and eliminates the need for liver biopsy. PATIENTS AND METHODS: Using the Cox proportional hazards analysis, we created a survival model based on 405 patients with PSC from 5 clinical centers. Independent validation of the model was undertaken by applying it to 124 patients who were not included in the model creation. RESULTS: Based on the multivariate analysis of 405 patients, a risk score was defined by the following formula: R = 0.03 (age [y]) + 0.54 loge (bilirubin [mg/dL]) + 0.54 loge (aspartate aminotransferase [U/L]) + 1.24 (variceal bleeding [0/1]) - 0.84 (albumin [g/dL]). The risk score was used to obtain survival estimates up to 4 years of follow-up. Application of this model to an independent group of 124 patients showed good correlation between estimated and actual survival. CONCLUSIONS: A new model to estimate patient survival in PSC includes more reproducible variables (age, bilirubin, albumin, aspartate aminotransferase, and history of variceal bleeding), has accuracy comparable to previous models, and obviates the need for a liver biopsy.

Adult↗

PubMed1999

Hepatic retransplantation in cholestatic liver disease: impact of the interval to retransplantation on survival and resource utilization.

The aim of our study was to quantitatively assess the impact of hepatic retransplantation on patient and graft survival and resource utilization. We studied patients undergoing hepatic retransplantation among 447 transplant recipients with primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) at 3 transplantation centers. Cox proportional hazards regression analysis was used for survival analysis. Measures of resource utilization included the duration of hospitalization, length of stay in the intensive care unit, and the duration of transplantation surgery. Forty-six (10.3%) patients received 2 or more grafts during the follow-up period (median, 2.8 years). Patients who underwent retransplantation had a 3.8-fold increase in the risk of death compared with those without retransplantation (P <.01). Retransplantation after an interval of greater than 30 days from the primary graft was associated with a 6.7-fold increase in the risk of death (P <.01). The survival following retransplantations performed 30 days or earlier was similar to primary transplantations. Resource utilization was higher in patients who underwent multiple consecutive transplantations, even after adjustment for the number of grafts during the hospitalization. Among cholestatic liver disease patients, poor survival following hepatic retransplantation is attributed to late retransplantations, namely those performed more than 30 days after the initial transplantation. While efforts must be made to improve the outcome following retransplantation, a more critical evaluation may be warranted for late retransplantation candidates.

Adult↗

PubMed1999

Relationship between surgically induced neuropathy and outcome of pelvic organ prolapse surgery.

The aim of the study was to determine whether surgically induced perineal neuropathy relates to the outcome of surgery for the correction of pelvic organ prolapse. Perineal nerve terminal motor latencies (PeNTML) were obtained in 31 women prior to and following transvaginal surgery for the correction of pelvic organ prolapse consisting of bilateral sacrospinous ligament vault suspension and bilateral paravaginal cystocele repair. Mean follow-up was 32 months (range 12-60). Surgical outcome was defined as optimal (asymptomatic, with the apex of the vagina above the levator plate with no tissue protruding beyond the hymen in the upright position with maximum Valsalva), or suboptimal (apical descent of > 50%, or any vaginal wall protrusion beyond the hymen in the upright position with maximum Valsalva). Surgically induced neuropathy was defined as an increase of 0.6 ms or more in the averaged right and left PeNTML measurements following the surgery. All women had preoperative symptomatic prolapse and the mean preoperative PeNTML was prolonged compared to established normals. Using strict definitions, 11 women had optimal outcome and 20 had suboptimal outcome. The outcome groups were similar with respect to age, weight, parity, degree of preoperative prolapse and preoperative perineal neuropathy. Eleven women had surgically induced perineal neuropathy. This was associated with suboptimal outcome compared to optimal outcome (P = 0.03). The relative risk of suboptimal outcome with surgically induced neuropathy was 1.82 (95% CI 1.13-2.93). It was concluded that a relationship exists between the outcome of organ prolapse surgery and surgically induced perineal neuropathy as measured by PeNTML. Such neuropathy may play a role in failed pelvic reconstructive surgery.

Female↗

PubMed1999

Fecal incontinence and the menstrual cycle: a case report.

Urinary tract dysfunction influenced by the menstrual cycle has been described. This case demonstrates mensturation-influenced fecal incontinence. The patient had difficulty with stool control and rectal hygiene only during the week prior to her period. These symptoms had been present since she had discontinued oral birth control. Progestin levels and anal manometry were obtained during the secretory and luteal phases of her cycle and demonstrated a difference in resting anal tone between phases. Progestin smooth muscle relaxation is presumed to have uncovered an already weakened anal continence mechanism. With reinstitution of oral contraceptive pills the patient's cyclic fecal incontinence resolved.

Adult↗

PubMed1999

Histologic analysis of needle biopsy of urethral sphincter from women with normal and stress incontinence with comparison of electromyographic findings.

OBJECTIVE: Our goal was to compare urethral sphincter biopsy and needle electromyography between women who had genuine stress incontinence and those who did not. STUDY DESIGN: Seventeen continent women and 10 women with stress incontinence had urethral sphincter needle electromyography and urethral biopsy specimens blindly processed for light and electron microscopy. RESULTS: The continent group had greater skeletal muscle content and percentage in each muscle fascicle and each urethral sphincter. The group with genuine stress incontinence had higher connective tissue content. All urethral skeletal muscle was type 1. The smooth muscle was "multiunit" type and was morphologically indistinguishable between the 2 groups. On electromyography, patients with genuine stress incontinence had significantly more fibrillation potentials, fewer motor unit action potentials, a higher percentage of polyphasia, and less maximum voluntary electrical activity than control subjects. CONCLUSIONS: Women with stress incontinence differ from continent women in skeletal muscle volume, amount of fibrosis, and electromyographic parameters; these differences support a neurogenic contribution to genuine stress incontinence. Urethral sphincter has only type 1 skeletal muscle and "multiunit" type smooth muscle.

Adult↗

PubMed1999

Association of compartment defects in pelvic floor dysfunction.

OBJECTIVE: Dynamic cystoproctography was used to determine the frequency of associated urinary, genital, and anorectal abnormalities in women with pelvic floor dysfunction. SUBJECTS AND METHODS: We categorized, by pelvic floor compartments, the symptoms at presentation of 100 consecutive female patients who had been referred for dynamic cystoproctography. We then analyzed the compartment defects seen on dynamic cystoproctography relative to those detected on clinical presentation. RESULTS: Of the 20 patients with symptoms of anterior compartment (urinary) defect, dynamic cystoproctography revealed that 45% had vaginal vault prolapse of more than 50% and that 90% had rectoceles. Of the 45 patients with symptoms of middle compartment (genital) defect, dynamic cystoproctography revealed that 91% had cystoceles, 56% had a hypermobile bladder neck, 82% had rectoceles, 58% had enteroceles, 11% had sigmoidoceles, 20% had rectoanal intussusception, and 16% had anal incontinence. Of the 17 patients with symptoms of posterior compartment (anorectal) defect, dynamic cystoproctography showed that 71% had cystoceles, 65% had a hypermobile bladder neck, and 35% had vaginal vault prolapse of more than 50%. Of the 18 patients with symptoms of defects from a combination of compartments, dynamic cystoproctography revealed that 89% had cystoceles, 56% had a hypermobile bladder neck, 39% had vaginal vault prolapse exceeding 50%, 100% had rectoceles (of which 45% were large), 6% had enteroceles, 6% had sigmoidoceles, 22% had rectoanal intussusception, and 6% had anal incontinence. CONCLUSION: Although patients may present with symptoms that involve only one compartment, a multicompartment prolapse is usually revealed on dynamic cystoproctography. Of the patients with pelvic floor dysfunction, 95% had abnormalities in all three compartments.

Fecal Incontinence↗

PubMed1999

Female pelvic organ prolapse: diagnostic contribution of dynamic cystoproctography and comparison with physical examination.

OBJECTIVE: The aim of this study was to assess the contribution of dynamic cystoproctography to the evaluation of female pelvic organ prolapse and to compare this contribution with that of physical examination. MATERIALS AND METHODS: The presence or absence of rectocele, enterocele, sigmoidocele, and cystocele on physical examination and on cystoproctography was retrospectively analyzed in 170 consecutive patients. For each of these diagnostic methods, organ prolapse was graded as small, moderate, or large on the basis of specific, defined measurements. RESULTS: A rectocele was detected by proctography in 155 patients (91%); 119 (77%) of these rectoceles were also found on physical examination. Barium trapping at proctography was related to rectocele size. Proctography showed an enterocele in 47 patients (28%); 24 (51%) of these enteroceles were also found on physical examination. Physical examination also found 44 enteroceles that could not be corroborated radiologically. At proctography, the enteroceles were relatively large, extending an average of 7.3 cm below the vaginal apex. Eight patients had sigmoidoceles, none of which were found on physical examination. A cystocele was shown by cystoproctography in 159 patients (94%); 132 (83%) of these cystoceles were also found on physical examination. CONCLUSION: The correlation between finding prolapsed pelvic organs on dynamic cystoproctography and finding them on physical examination varies. Most radiographically detected rectoceles and cystoceles are found on physical examination, whereas the correlation for enteroceles and sigmoidoceles is poor. Dynamic cystoproctography provides direct visualization and quantification of female pelvic organ prolapse, information that usually can only be inferred by physical examination.

Adult↗