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Biomedical subjects

G E Lemack

Publications and source records attributed to G E Lemack.

27 records · Page 2Linked to original sources
PubMed1999

Physiologic sequelae of partial infravesical obstruction in the mouse: role of inducible nitric oxide synthase.

PURPOSE: To develop a mouse model for partial infravesical obstruction, and determine the resultant changes in bladder function, with particular emphasis on the role of inducible nitric oxide synthase (iNOS) in the bladder response. MATERIALS AND METHODS: Wild type mice were subjected to no intervention, sham operation, and varying durations of partial outlet obstruction (1, 3, and 5 weeks). They then underwent cystometric evaluation, bladder strip stimulation studies using carbachol, and relaxation studies using l-arginine, sodium nitroprusside, and 8-bromoguanosine 3'-5' cyclic guanosine monophosphate. Bladder tissue was subjected to RT-PCR and Western analysis for iNOS. Bladders were also studied histologically using morphometric analysis. RESULTS: Bladders from mice obstructed for 5 weeks were heavier (weight increased by 110%), larger (capacity increased by 73%), and had a higher frequency of abnormal appearing cystometric curves than normal bladders. Tissue bath studies demonstrated decreased contractility in response to cholinergic stimulation at 5 weeks of obstruction (decreased by 55% at maximal stimulation). RT-PCR demonstrated iNOS in approximately 70% of bladders obstructed for 1 and 3 weeks, while the iNOS protein was apparent in 50% of the bladders from the same groups. CONCLUSIONS: This new animal model of infravesical obstruction is reliable and reproducible. Moreover, the physiologic changes noted are comparable to other models, but an added advantage is the relevance of this model with regard to studying new transgenic or knockout mice. Enhanced expression of iNOS seen early after obstruction may serve to improve oxygenation during obstruction-induced ischemia.

Animals↗
PubMed1999

The effects of mesh bioprosthesis on the spermatic cord structures: a preliminary report in a canine model.

PURPOSE: The use of mesh bioprosthesis during inguinal herniorrhaphy is now considered routine. To our knowledge, no studies have examined the effects of mesh induced fibrosis on the structure and function of the adjacent spermatic cord. We present our experience in a canine model. MATERIALS AND METHODS: Unilateral inguinal hernia defects were created in 12 male beagle dogs. Half were repaired using Marlex mesh and half using a classic Shouldice technique. The inguinal anatomy was then re-examined at 6 and 12 months. Testicular temperature and volume, peripheral and testicular vein testosterone levels, testicular blood flow, vasography, testicular and cord histology, and sperm motility/morphology were recorded. Groups were compared with each other as well as to the non-operated (control) side. RESULTS: Although post-operative testicular volumes from both the mesh and Shouldice groups were similar to controls (p >0.05), there was a downward trend after mesh repair (17.8 cc pre versus 12.6 cc post) but this did not reach statistical significance (p = 0.17). Testicular temperatures and blood flow did not differ between experimental groups and controls. While testicular vein testosterone levels were significantly higher than peripheral venous levels after Shouldice repair, this difference was lost after mesh repair. Contralateral (control) testicular vein testosterone levels were higher in animals repaired with mesh than by an anatomic Shouldice repair (p <0.05). There was a significant decrease in cross sectional vasal luminal diameter in both the anatomic and mesh repair groups versus their respective contralateral controls (p <0.05). This was correlated with a marked foreign body reaction to the mesh in the soft tissues surrounding the vas in spermatic cords exposed to Marlex. All vasograms demonstrated patency. Gross pathology was abnormal in 3/6 dogs with mesh repair (2 hydroceles and 1 ischemic testis) and 0/6 animals after Shouldice repair. A traumatic neuroma was identified in the mesh group. Sperm morphology and motility did not differ between the two groups. CONCLUSIONS: Half of the testicles had gross abnormalities after mesh repair versus none in the control and Shouldice dogs. Although all vasograms were patent, vasal luminal size was significantly decreased with a marked soft tissue foreign body reaction identified after mesh repair. A traumatic neuroma was identified suggesting nerve entrapment in the fibrotic mesh reaction, which may account for post-operative pain seen in some patients. Marlex mesh may adversely affect spermatic cord structure and function and further work is required to fully elucidate its effects.

Animals↗
PubMed1999

Reversing the tide: emerging options for treating overactive bladder symptoms in women.

The symptom complex of urinary urgency, frequency, nocturia, and urge incontinence, also known as the "overactive bladder" syndrome, affects the lives of millions of American women. As the symptoms are nonspecific, several different etiologies may be responsible. In many women, however, no discernible source can be identified. If a basic evaluation, including history, physical examination, urinalysis, and postvoid residual determination, fails to identify a source for the complaints, empiric treatment with behavioral intervention or a trial of medication may be offered to control symptoms. Certain patients will require a more detailed evaluation, particularly if conservative measures fail to provide relief. The role of advanced diagnostic strategies and the emergence of new treatment modalities are discussed.

Aged↗
PubMed1998

Microsurgical repair of the adolescent varicocele.

PURPOSE: Since clinically apparent varicoceles may affect testicular volume and sperm production, early repair has been advocated. However, repair of the pediatric varicocele with conventional nonmagnified techniques may result in persistence of the varicocele after up to 16% of these procedures. Also testicular artery injury and postoperative hydrocele formation can occur after nonmagnified repair. The microsurgical technique has been successfully completed in a large series of adults with a dramatic reduction in complication and recurrence rates. We report our experience with the microsurgical technique in boys. MATERIALS AND METHODS: A total of 30 boys (average age 15.9 years) underwent 42 microsurgical varicocelectomies (12 bilateral). All patients had a large left varicocele. Indications for repair included testicular atrophy (size difference between testicles of greater than 2 ml.) in 20 boys, pain in 5 and a large varicocele without pain or testicular atrophy in 5. Six boys were referred following failure of conventional nonmicrosurgical techniques. All boys were examined no sooner than 1 month postoperatively (mean followup 12). RESULTS: Preoperative volume of the affected testis averaged 13.0 ml., and an average size discrepancy between testicles of 2.8 ml. was noted before unilateral varicocelectomy. No cases of persistent or recurrent varicoceles were detected, and 1 postoperative hydrocele resolved spontaneously. After unilateral varicocelectomy the treated testes grew an average of 50.1%, while the contralateral testes grew only 23%. Overall, 89% of patients with testicular atrophy demonstrated reversal of testicular growth retardation after unilateral varicocelectomy. In contrast, both testes showed similar growth rates after bilateral varicocelectomy (45% left testis, 39% right testis). CONCLUSIONS: The meticulous dissection necessary to preserve arterial and lymphatic supply, and to ligate all spermatic veins in the pediatric patient is readily accomplished using a microsurgical approach, and results in low recurrence and complication rates. Rapid catch-up growth of the affected testis after microsurgical varicocelectomy suggests that intervention during adolescence is effective and warranted.

Adolescent↗
PubMed1996

Laparoscopic orchiopexy: clinical experience and description of technique.

PURPOSE: We reviewed the experience, early followup and technique of laparoscopic treatment of the nonpalpable undescended testis at our institution. MATERIALS AND METHODS: Charts of patients who underwent laparoscopic treatment of an intra-abdominal testis from September 1992 to October 1994 were reviewed. RESULTS: A total of 13 laparoscopic orchiopexies was performed on 11 children with nonpalpable undescended testes. In 10 cases sufficient length was gained on the spermatic vessels using laparoscopic dissection to perform tension-free orchiopexy without the need for division of the spermatic vessels. CONCLUSIONS: When localization of an intra-abdominal testis is confirmed, orchiopexy can be performed safely with minimal morbidity using a laparoscopic approach. Length of hospital stay and postoperative morbidity may be improved in comparison to traditional techniques.

Child↗
PubMed1996

Presence of sperm in the pre-vasectomy reversal semen analysis: incidence and implications.

PURPOSE: We determined the incidence of sperm in the ejaculate before vasectomy reversal, and correlated this result with intraoperative and postoperative findings. MATERIALS AND METHODS: Before vasectomy reversal semen was analyzed and granulomas were palpated in 186 men. The results were correlated with intraoperative vasal fluid and postoperative semen analyses. RESULTS: Of 18 men (9.7%) with sperm present in the pre-reversal analysis 94% had sperm in at least 1 vas intraoperatively. The presence of palpable granulomas at the vasectomy site did not correlate with either pre-reversal or post-reversal semen analyses, or the presence of sperm in the vasal fluid intraoperatively. CONCLUSIONS: Sperm are present in 9.7% of pre-reversal ejaculates and predict sperm in at least 1 vas intraoperatively. These findings also suggest the possibility of late vasectomy failures.

Adult↗
PubMed1995

Urologic causes of gynecomastia: approach to diagnosis and management.

A 27-year-old man presented with bilateral painful breast enlargement and recent onset right testicular swelling. After appropriate evaluation, a radical orchiectomy was performed, and a Leydig cell tumor was found. The various urologic etiologies for gynecomastia are presented, as are the potential interventions. A rational approach to the patient with new onset breast swelling is presented.

Adrenal Gland Neoplasms↗
PubMed1995

Genitourinary reconstructive surgery utilizing laser tissue welding.

Laser tissue welding contributes several distinct advantages over current tissue approximation methods in the genitourinary tract. Low level laser energy combined with a protein solder can provide an immediate watertight seal that is supraphysiologic, nonlithogenic, rapid, and reliable. This review highlights the history of laser tissue welding, its applications to urologic surgery, recent developments to improve the technique, and future directions.

Animals↗