Search PubMed⌕ Search

Biomedical subjects

J G Blaivas

Publications and source records attributed to J G Blaivas.

12 recordsLinked to original sources
PubMed1992

The cholinergic and purinergic components of detrusor contractility in a whole rabbit bladder model.

Whole rabbit bladders were suspended in a bath chamber and stimulated with ATP, bethanechol, electrical field stimulation, and bethanechol + ATP. Detrusor pressure and fluid expelled by the bladder were recorded, synchronized, and digitized. Detrusor work and power were calculated with a computer program. Maximum work was 61.4 +/- 28.7, 83.3 +/- 17.0, 85.0 +/- 15.0, 90.8 +/- 13.1 cm. H2O, ml. for ATP, bethanechol, electrical and bethanechol + ATP, respectively. Maximum power generated by ATP was 4.8 +/- 3.0 cm. H2O, ml./sec and was approximately 66% of that generated by bethanechol, and 50% of that generated by electrical stimulation, and bethanechol + ATP. ATP cannot empty the bladder with moderate outlet resistance while bethanechol and electrical stimulation can. Our results suggest that ATP is able to generate detrusor power and achieve work in bladder emptying. However, ATP generated power and work is considerably less than that of electrical stimulation or bethanechol alone. ATP mediated contraction is not inhibited by atropine or tetrodotoxin but is inhibited by P2 purinoceptor desensitization, suggesting a functional role of purine receptors on detrusor smooth muscle. Since ATP generated pressure is more rapid than with bethanechol alone, we support the hypothesis that ATP may be important in the initiation of micturition.

Adenosine Triphosphate↗
PubMed1990

Multichannel urodynamic studies in men with benign prostatic hyperplasia. Indications and interpretation.

Recent studies suggest that clinical "prostatism" encompasses at least four conditions that may be present singly or in combination: prostatic urethral obstruction, impaired detrusor contractility, detrusor instability, and sensory urgency. In addition, primary vesical neck obstruction may be present in the absence of benign prostatic hyperplasia (BPH). Thus, the purpose of diagnostic evaluation in men with BPH is to identify precisely the pathophysiology of the patient's symptoms so that rational therapy can be selected.

Humans↗
PubMed1979

Vesicourethral dysfunction in multiple sclerosis.

Urodynamic evaluation was done 45 times on 41 consecutive patients with multiple sclerosis. Bladder symptoms correlated poorly with any single urodynamic finding and, accordingly, a comprehensive evaluation was necessary to define the underlying pathophysiology. Only 63 per cent of the patients with symptoms of urgency, frequency and urge incontinence actually were found to have uninhibited bladder contractions, while 73 per cent of the patients with obstructive symptoms had detrusor areflexia. Six patients (15 per cent) had a marked change in urodynamic findings upon repeat examination either because of a change in symptomatology or poor response to treatment. An additional 6 patients had vesicoureteral reflux. Bladder symptoms in multiple sclerosis patients should serve more to alert the clinician to the need for urodynamic testing than to mandate specific treatment.

Adult↗
PubMed1977

Idiopathic pelviureteric varices.

Pelviureteric varices are well-documented sequelae of renal vein thrombosis, but there have been only 10 prior reports of idiopathic renal vein varicosities. Herein we report 3 more cases and review the literature. Two thirds of the patients presented with hematuria; one-fourth had flank pain, and one-third had saphenous vein varicosities. Pyelographic findings include scalloped deformities of the upper ureter and pelvis with displacement and intraluminal filling defects. The diagnosis may be suspected from the excretory urogram, but venography is definitive. Excision and ligation of the varicose veins were curative in all but 3 patients who required nephrectomy for life-threatening hemorrhage.

Adult↗
PubMed1977

Primary renal artery dissecting aneurysm: a review.

Primary dissecting aneurysms of the renal artery are exceedingly rare. Our recent encounter with a patient with this condition prompted a review of the literature. The diagnostic and therapeutic problems in 30 patients were analyzed and guide lines for proper management were discussed. The triad of flank pain, hematuria and hypertension of acute onset in the absence of urinary obstruction should suggest this rare condition.

Adult↗
PubMed1977

A new approach to electromyography of the external urethral sphincter.

Detailed electromyographic investigation of the external urethral sphincter was done as part of a urodynamic evaluation of 119 patients. The sphincter was located by inserting electrodes alongside the urethra. The electromyogram was viewed on an oscilloscope and recorded on paper. Normal and abnormal sphincter electromyograms were defined and the role of sphincter electromyography in urodynamic studies was discussed. It was observed that electromyographic activity does not always correlate with urethral resistance but must be interpreted in conjunction with other urodynamic parameters, such as urethral pressures, urinary flow rates and voiding cystourethrography. In addition, sphincter electromyography provides valuable information to define the various neural pathways involved in micturition and continence.

Electromyography↗
PubMed1977

Changing concepts in the urodynamic evaluation of children.

Urodynamic evaluation was performed in 46 children with myelodysplasia, spinal cord injury, enuresis, postoperative incontinece, sacral agenesis and recurrent urinary tract infection. The basic study consisted of voiding cystourethrography followed by the simultaneous recording of intra-abdominal and intravesical pressure with external urethral sphincter electromyography. Urethral pressure profile, urinary flow rate and anal sphincter electromyography were performed selectively. There was no correlation between the clinical neurological level and the cystometric pattern in patients with spinal cord lesions. Bladder-external sphincter dyssynergia was associated with a high post-void residual urine in children with hypertonic bladders, while in children with hypotonic bladders dyssynergia did not affect the post-void residual. Since, urinary symptoms bore little relationship to urodynamic findings in our study we recommend complete evaluation of children who have persistent disturbances of micturition.

Adolescent↗
PubMed1976

Paraurethral cysts in female neonate.

Paraurethral cysts in the female neonate are uncommon lesions. All reported cases have either ruptured spontaneously or responded to simple marsupialization. However, complete urologic evaluation is mandatory because they simulate ectopic ureteroceles in appearance. Herein is reported our experience with 5 patients. The etiology, embryogenesis, natural history, differential diagnosis, and treatment are discussed.

Cysts↗
PubMed1975

Chemolysis of residual stone fragments after extensive surgery for staghorn calculi.

Chemical dissolution of residual stone fragments was attempted in twelve instances via nephrostomy tube irrigation. Appropriate solutions containing either hemiacidrin or sodium bicarbonate were used for struvite and uric acid stones, respectively. Precautions were taken to prevent and recognize outflow obstruction and urinary infection. Seventy-five per cent of the stones so treated were completely dissolved, and there were no major complications. The incidence of retained stones, natural history, and indications for chemical dissolution are reviewed.

Adult↗