Search PubMed⌕ Search

Biomedical subjects

S Raz

Publications and source records attributed to S Raz.

At least 73 records · Page 4Linked to original sources
PubMed1991

In vivo characterization of the inflammatory properties of poly(tetrafluoroethylene) particulates.

Suburothelial injections of particulate poly(tetrafluoroethylene) (PTFE) is becoming a widely accepted treatment for a number of urological disorders. Because little is known about the long-term histologic morphology of the injection site, this animal study was performed. Three populations, each consisting of two mongrel dogs, five New Zealand White rabbits, and 10 BALB/c mice, were injected with poly(tetrafluoroethylene) particulate in a glycerine carrier (Polytef Paste) and were followed for a period of 1 week, 3 months, 6 months, and 1 year. Mice received one subcutaneous dorsal injection each, rabbits received two subareolar injections each, and dogs received three subareolar injections each in addition to two periurethral injections. Histologic examination of the biopsy sites revealed a persistent chronic inflammatory reaction with progressive growth of the involved tissue volume. In addition to giant cells and macrophages, lymphocytes became apparent at 3 months and constituted up to 40% of the cellular infiltrate by 1 year. Plasma cells were also noted at the 1-year period in the rabbit model. The progressive growth of the inflammatory pseudo-tumors evoked by injected PTFE may compromise the long-term safety of certain urological procedures involving particulate PTFE.

Acute Disease↗
PubMed1991

Extended double-J ureteral stent.

Continent forms of urinary diversion using intestinal segments are becoming increasingly common. As this new treatment modality evolves, our instruments and mechanical devices are likewise evolving and adapting to the changing needs placed on them. We have used a new type of double-pigtail ureteral catheter in patients requiring continent urinary diversion. It allows stenting of the ureteral-intestinal anastomosis and safeguards against urinary leak or extravasation; at the same time the catheter is accessible to the outside for easy replacement, manipulation, and radiographic evaluation. The catheter has also shown to be useful for other purposes such as uretero-neo-cystostomy. This is particularly important in the pediatric population where repeated cystoscopy for stent removal or manipulation can be a significant drawback.

Equipment Design↗
PubMed1991

Kidney stone formed around refluxed surgical staple and removed by transureteral endoscopic manipulation.

We present a case of a kidney stone that developed around a surgical staple which refluxed up to the kidney following a Bricker urinary diversion and bilateral ureteroileal anastomosis. A GIA stapler had been utilized to construct the ileal conduit. The stone was retrieved by means of flexible ureterorenoscopy through the ileal conduit. To our knowledge, this is the first report of such a complication following construction of an ileal conduit with a stapling device.

Adult↗
PubMed1991

Repair of severe anterior vaginal wall prolapse (grade IV cystourethrocele).

The classical approach for the repair of severe anterior vaginal wall prolapse is the use of transvaginal colporrhaphy or, more recently, an abdominal paravaginal repair. Severe cystoceles develop from weaknesses of the levator sling and pubocervical fasciae resulting in 2 main anatomical changes: a central defect between the pubocervical fasciae, and a sliding herniation of the bladder and urethra (paravaginal defect). We developed a new transvaginal technique for the repair of large cystoceles (grade IV) extending outside of the introitus at rest, which includes repair of the central defect by anterior colporrhaphy, and repair of the paravaginal herniation of the bladder base and bladder neck by a needle suspension of these structures. We report our experience within a 5-year period in the treatment of 51 cases of severe bladder prolapse (grade IV cystoceles), 46 of which required this combined procedure regardless of preoperative stress urinary incontinence status. Five patients underwent anterior colporrhaphy as the only procedure, since they were continent and demonstrated a well supported bladder neck from a previous suspension operation. Other vaginal abnormalities should be repaired simultaneously to provide adequate pelvic floor support.

Adult↗
PubMed1991

Learning from experience--a revised approach to quality assurance.

This article introduces a model for directing quality assurance activity in hospitals outside of the US. We believe that this model will be more expedient than the systems presently in use. The rationale for this new approach is based on the American experience but proposes an improved organizational and scientific method that has evolved to replace the previously existing ad hoc committees and punitive, post-factum approach. The suggested model includes the establishment of an inter-related network of institutional and departmental committees coupled with the active participation of the hospital director and a specialized unit for quality assurance activities. This approach has the potential for affording major improvements in the implementation of quality assurance in hospitals, outside of the US, which have not been part of the evolutionary process which has taken place in America.

Decision Making, Organizational↗
PubMed1990

Role of the Na+/K+/Cl- transporter in the positive inotropic effect of ouabain in cardiac myocytes.

In this study we have characterized the bumetanide-sensitive K+/Na+/Cl- cotransport in cultured rat cardiac myocytes. 1) It carries about 10% of the total K+ influx. 2) It is sensitive to furosemide (Ki0.5 = 10(-6)M) and bumetanide (Ki0.5 = 10(-7)M). 3) It is strongly dependent on the extracellular concentrations of Na+ and Cl-. 4) It carries out influx of both ions, K+ and Na+. A therapeutic concentration of ouabain (10(-7) M) stimulated the bumetanide-sensitive K+ influx (as measured by 86Rb+), in the cultured myocytes, with no effect on the bumetanide-resistant K+ influx, which was mediated mostly by the Na+/K+ pump. Stimulation of the bumetanide-sensitive Rb+ influx by a low ouabain concentration was strongly dependent on Na+ and Cl- in the extracellular medium. A low concentration of ouabain (10(-7) M) was found to increase the steady-state level of cytosolic Na+ by 15%. This increase was abolished by the addition of bumetanide or furosemide. These findings suggest that ouabain, at a low (10(-7) M) concentration, induced its positive inotropic effect in rat cardiac myocytes by increasing Na+ influx into the cells through the bumetanide-sensitive Na+/K+/Cl- cotransporter. In order to examine this hypothesis, we measured the effect of bumetanide on the increased amplitude of systolic cell motion induced by ouabain. Bumetanide or furosemide, added to cultured cardiac myocytes, inhibited the increased amplitude of systolic cell motion induced by ouabain. Neither bumetanide nor furosemide alone has any significant effect on the basal amplitude of systolic cell motion. We propose that stimulation of bumetanide-sensitive Na+ influx plays an essential role in the positive inotropic effect in rat cardiac myocytes induced by low concentration of ouabain.

Animals↗
PubMed1990

The anatomy of stress incontinence: magnetic resonance imaging of the female bladder neck and urethra.

Clinical, urodynamic, radiological and endoscopic evaluations as well as operative results on more than 800 cases of stress incontinence treated at our medical center have led to a better understanding of the pathophysiology of female stress incontinence. We attempt to correlate these physiological concepts with information obtained from magnetic resonance images of the paraurethral and bladder neck areas in patients with known stress incontinence and normal controls. All magnetic resonance images were compared to cadaver step sections of the female pelvis. Normal controls without stress incontinence were used to define normal anatomy by magnetic resonance imaging. Etiology of incontinence was divided into either intrinsic urethral damage or anatomical malposition of an intact sphincteric unit. Our findings not only provide valuable support to basic concepts of the pathophysiology of stress incontinence but also help to establish normal findings of female paraurethral and bladder neck anatomy as seen by magnetic resonance imaging.

Female↗
PubMed1990

Tapered intraluminal versus imbricated extraluminal valve: comparison of two continence mechanisms for urinary diversion.

One of the major limitations of continent intestinal reservoirs currently in use is failure of the efferent continence mechanisms. Unsatisfactory results have been reported in the literature in up to 40% of cases. While progress has been made toward better continence in urinary diversions, evolution of the actual continence mechanisms has been along two rather distinct paths: those with a valve mechanism placed inside the pouch (either by intussusception or surgical insertion), and those with the valve outside to the pouch (by imbrication of an externally located ileal segment). A canine experimental model was used to investigate a type of intraluminal continence mechanism and to compare it to an extraluminal imbricated ileocecal valve. In eight mongrel dogs a reservoir was made out of ascending and transverse colon with two different valve mechanisms--one intraluminal and one extraluminal--connected via separate stomas to the skin. Radiographic, sonographic, endoscopic and urodynamic studies of the pouch and its outlets were performed. Results showed that, in contrast to the extraluminal valve, continence in the intraluminal valve was volume dependent. The valve closing pressure of the intraluminal continence mechanism increased far beyond the values of the extraluminal valve (50.38 vs. 30.12 cm. H2O) at maximum pouch filling. Leakage of the intraluminal valve was observed at significantly higher pouch volumes than in the extraluminal valve (348 cc vs. 215 cc). In view of these results, the volume dependent intraluminal valve mechanism appears superior to an extraluminal type, especially at higher pouch volumes.

Animals↗
PubMed1990

Basic evaluation of female urinary incontinence.

Urinary incontinence is a common disorder that is frequently underreported because of its social implications. Although several types of urinary incontinence are recognized, they can be generally classified as failure of the bladder to store or failure of the urethral mechanism. A systematic approach for the evaluation of incontinence that includes history, physical examination, basic laboratory tests, and often urodynamic evaluation, offers the most comprehensive assessment of the etiology of incontinence.

Aged↗
PubMed1990

Structural brain abnormalities in the major psychoses: a quantitative review of the evidence from computerized imaging.

The neuroimaging literature on structural brain abnormalities in the major psychoses is quantitatively reviewed. The mean effect size for studies of lateral ventriculomegaly in schizophrenia (d = .70) corresponded to 43% nonoverlap between the distributions of schizophrenics and control Ss. Planimetry yielded larger effects than linear methods of ventricular size estimation. Although enlargement of the third ventricle was comparable to that of lateral ventriculomegaly (d = .66), it was found to be significantly greater after differences in measurement method were taken into account. The average cumulative length of hospitalization, adjusted for patients' age and duration of illness, predicted ventriculomegaly in schizophrenia. Studies on schizophrenia and affective disorder differed neither in the extent of reported ventriculomegaly nor in the amount of "cortical atrophy."

Brain↗
PubMed1989

Spurious impotence after hypospadias repair.

A fifteen-year-old who had undergone multiple hypospadias repairs alleged erectile dysfunction as a result of his surgery. A new method of nocturnal penile tumescence and rigidity monitoring supplied objective evidence to refute this allegation. Attention is drawn to the need for and availability of written documentation when diagnosing the presence or absence of erectile ability.

Adolescent↗
PubMed1989

Four-corner bladder and urethral suspension for moderate cystocele.

The classical approach to cystocele repair involves the approximation of lax pubocervical fascia through the anterior vaginal wall with narrowing of the bladder neck and proximal urethra by the Kelly-type plication. This procedure corrects the prolapse but when performed for the treatment of incontinence it has a high failure rate because the bladder neck and urethra are not placed into a high, supported, nonobstructed retropubic position. Furthermore, due to elevation of the bladder base without simultaneous elevation of the bladder neck and urethra, de novo stress urinary incontinence may occur. We developed a transvaginal needle suspension operation for the bladder and urethra that repairs anterior vaginal wall prolapse with excellent support of the bladder base and repositions the bladder neck in the high retropubic position, all during a simple and rapid operation that is tolerated well by the patient.

Female↗
PubMed1989

Vaginal wall sling.

We describe a new technique for the treatment of urinary incontinence due to intrinsic sphincteric damage in which a sling constructed from vaginal wall is used to provide compression and support of the urethra. A rectangular island of in situ anterior vaginal wall underlying the urethra and bladder neck is developed, the 4 corners are anchored with polypropylene sutures and a ligature carrier is used to transfer the sutures to a suprapubic location. An anterior vaginal wall flap proximal to the island is advanced to cover the island. When the sutures are tied the resulting sling will support the urethra and increase urethral resistance by compression, restoring continence. The advantages are its simplicity, need for only a small incision, short operative time and hospital stay, and reliance on healthy, well vascularized, in situ tissue. Continence has been achieved in 29 of 32 cases. All patients voided spontaneously except for those with neuropathic urethral incompetence who required self-catheterization.

Adult↗