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Timothy G Schuster

Publications and source records attributed to Timothy G Schuster.

16 recordsLinked to original sources
PubMed2006

Epididymal obstruction results in isolated sperm heads in post-vasectomy rats.

The aim of this study was to determine if, following vasectomy, epididymal obstruction resulted in changes in vasal stump fluid using a rat vasectomy model. One hundred and twenty-two mature male rats underwent bilateral surgical vasectomy and subsequent unilateral epididymal obstruction. Animals were randomly assigned to one of the five cohorts, which determined the time to kill and vasal fluid assessment. Numbers of whole sperm and sperm heads were compared between the obstructed and non-obstructed sides. Parametric analysis of microscopic vasal fluid findings was performed using a paired t-test. Whole sperm and sperm heads were detected bilaterally among the initial five cohorts. On the obstructed epididymis side, percentage of whole sperm dropped from 36.9% to less than 1% and sperm heads increased from 63.2 to 99.7% at 12 weeks post-obstruction (p < 0.05 at each time interval). On the unobstructed side, percentage of whole sperm rose from 66.3 to 89.5% and sperm heads dropped from 33.7 to 10.5% (p < 0.05 at each time interval). At 12 weeks, the difference between the obstructed and non-obstructed sides for both percentage and quantity of whole sperm and heads was significant with a p value of <0.001. In this rat model, following vasectomy and subsequent epididymal obstruction, testicular vasal stump fluid will contain progressively diminishing numbers of whole sperm and increases in the percentage and absolute numbers of sperm heads.

Animals↗
PubMed2006

Premature ejaculation.

Premature ejaculation is a common entity that can have a significant impact on an individual's sexual satisfaction and quality of life. Both behavioral and pharmacological options are available and effective for men presenting with this condition.

Adrenergic alpha-Antagonists↗
PubMed2003

Passively driven integrated microfluidic system for separation of motile sperm.

This paper describes a self-contained integrated microfluidic system that can separate motile sperm from small samples that are difficult to handle using conventional sperm-sorting techniques. The device isolates motile sperm from nonmotile sperm and other cellular debris, based on the ability of motile sperm to cross streamlines in a laminar fluid stream. The device is small, simple, and disposable yet is an integrated system complete with sample inlets, outlets, sorting channel, and a novel passively driven pumping system that provides a steady flow of liquid; it requires no external power source or controls. The device fulfills a need in clinical settings where small amounts of sperm need to be sorted. It also opens the way for convenient bioassays based on sperm motility including at-home motile sperm tests.

Cell Separation↗
PubMed2003

Legal considerations for cryopreservation of sperm and embryos.

OBJECTIVE: To summarize the case law for cryopreservation of sperm and embryos and make recommendations for desirable characteristics that should be included in a cryopreservation clinic's disposition agreements. DESIGN: A literature review of case law and legal review articles was performed. SETTING: Academic research center. PATIENT(S): None. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): None. RESULT(S): Two court cases involving cryopreserved semen and five cases involving cryopreserved embryos are reviewed. CONCLUSION(S): The state of the law surrounding cryopreservation is recent and unsettled. Disposition agreements can provide cryopreservation clinics some degree of certainty in this unsettled area of law. Those drafting cryopreservation disposition agreements are assisted by lessons learned from cryopreservation cases and insight gained from law review articles. It is evident that cryopreservation agreements will be most successful and most likely to be enforced if they are unambiguous, consistent with public policy, and include: a duration provision, each individual's contact information, the individual's provisions for use of their gametes in case of death, and responsibilities of cryopreservation clinic and individuals. Individuals must enter into agreements with a true understanding of the contained provisions.

Contracts↗
PubMed2003

Radical cystectomy for bladder cancer after definitive prostate cancer treatment.

OBJECTIVES: To review our perioperative experience with patients presenting with high-risk bladder cancer who had undergone prior therapy for prostate cancer. With the increase in diagnosis and subsequent treatment of prostate cancer, more patients presenting with high-risk bladder cancer have undergone prior therapy for prostate cancer. Radical cystectomy in these patients can be technically challenging and may be associated with added morbidity. METHODS: A retrospective review of 458 patients treated with radical cystectomy between January 1993 and January 2002 revealed 29 patients (mean age 72 years) who had received definitive treatment for prostate cancer prior to cystectomy for bladder carcinoma. The initial treatment in this cohort was radical prostatectomy or external beam radiotherapy in 12 (41%) and 17 (59%) men, respectively. Cystectomy was performed for transitional cell carcinoma in 25 (86%), small cell carcinoma in 2 (6%), and sarcoma in 2 (6%) patients. RESULTS: At the time of cystectomy, the mean blood loss was 1175 mL (range 275 to 3500), and the median length of hospitalization was 8 days (range 4 to 23). No intraoperative or perioperative deaths occurred in this cohort. Twenty-seven early complications were identified in 16 (55%) of 29 patients; no rectal injuries occurred. Patients with prior radiotherapy had a higher rate of extravesical bladder carcinoma (60%) than those patients treated with prior prostatectomy (33%). An orthotopic neobladder diversion was created in 5 patients (17%). CONCLUSIONS: Patients with bladder cancer previously treated for prostate cancer with external beam radiotherapy or radical prostatectomy have an increased risk of perioperative complications compared with patients undergoing cystectomy without prior therapy. This risk is not prohibitive, and radical cystectomy should remain the treatment of choice for high-risk bladder cancer in this population. Furthermore, orthotopic urinary diversion may be a reasonable option and should be considered in select patients.

Aged↗
PubMed2003

Safety and efficacy of same-session bilateral ureteroscopy.

PURPOSE: Same-session ureteroscopy for bilateral urinary calculi would potentially reduce costs and the need for a second anesthetic compared with staged procedures. We sought to establish the safety and efficacy of same-session bilateral ureteroscopy relative to procedures for staged bilateral and multiple unilateral calculi in the context of contemporary instrumentation. PATIENTS AND METHODS: A series of 626 consecutive patients underwent ureteroscopy for calculi between January 1997 and August 2001. Among these, 34 patients with bilateral calculi (11 staged and 23 treated in one sitting) and 54 patients with multiple unilateral calculi in distinct locations were included in this study. Multivariable regression was used to determine the association of patient-specific and technical factors with postoperative morbidity. RESULTS: Stone-free rates were similar in the two groups and ranged from 50% to 100% depending on stone location. Postoperative complications occurred in 6 (11%) and 3 (14%) of the patients treated for multiple unilateral and for bilateral calculi in a staged procedure, respectively, compared with 7 (29%) of those undergoing same-session bilateral ureteroscopy (P = 0.12). Logistic regression revealed that same-session bilateral ureteroscopy (odds ratio [OR] 4.0; P = 0.02) and absence of a postoperative stent (OR 1.7; P = 0.03) were associated with added morbidity. However, the cumulative risk of performing staged bilateral procedures (14% per procedure) approximated that of bilateral ureteroscopy in one sitting (29%). CONCLUSION: Bilateral ureteroscopy carries an increased risk of postoperative morbidity. The risk is proportional to the number of renal units treated and may be assumed at once (e.g., same-session) or over time (e.g., staged) as it applies to patients requiring bilateral ureteroscopy.

Adult↗
PubMed2003

Ultra-rapid freezing of very low numbers of sperm using cryoloops.

BACKGROUND: With the availability of ICSI, men with severe oligozoospermia (<5x10(6)/ml) are able to reproduce. Current methods for cryopreservation of severe oligozoospermic samples are labour intensive and costly. The objective of this study was to evaluate whether freezing small numbers of motile sperm (approximately 100) was feasible using cryoloops. METHODS: Initial tests assessed the effect of various dilutions of cryoprotectants on pre-freezing sperm motility. Several solutions were further evaluated for their ability to cryoprotect sperm during ultra-rapid freezing. Sperm were placed on cryoloops and held in liquid nitrogen vapour for 5 min prior to freezing (ultra-rapid freezing) or directly submerged into liquid nitrogen. Using the optimal cryoprotectant and technique from these experiments, ultra-rapid and standard slow-rate freezing protocols were compared. RESULTS: Optimal sperm survival was seen when sperm in cryoloops were placed in liquid nitrogen vapour in test yolk buffer with 12% v/v glycerol versus other cryoprotectants. Using this cryoprotectant, post-thaw sperm motility is comparable between ultra-rapid and slow-rate freezing methods. CONCLUSION: Ultra-rapid freezing of very low numbers of sperm is feasible using cryoloops suspended in liquid nitrogen vapour for 5 min.

Cell Survival↗
PubMed2003

Identifying patients who are suitable for stentless ureteroscopy following treatment of urolithiasis.

PURPOSE: Foregoing ureteral stents following ureteroscopy for urinary calculi is an evolving practice. Randomized trials support stent omission in select cases though generalizability is unclear and criteria for stentless ureteroscopy are unknown. Therefore, we sought to identify significant clinical characteristics affecting postoperative morbidity in unstented patients to provide a context for future randomized trials. MATERIALS AND METHODS: Of 837 ureteroscopic procedures for urolithiasis performed at our institution from January 1997 through January 2002 a ureteral stent was not placed in 226 (32%). Among these patients 47 had no stone at the time of the procedure leaving 219 (26%) who were treated for urinary calculus disease. Multivariate logistic regression was used to determine the association of 24 variables with postoperative morbidity. RESULTS: Of the 219 patients treated with ureteroscopy 39 (18%) had a postoperative complication, which was obstructive in 26 (12%), infectious in 10 (5%), and related to patient co-morbidity in 3 (1%). Factors associated with postoperative morbidity included renal pelvic location (p = 0.02), lithotripsy (p = 0.03), bilateral procedure (p = 0.07), history of urolithiasis (p <0.0001), diabetes mellitus (p = 0.06), recent/recurrent infection (p <0.0001), operative time 45 minutes or greater (p = 0.07), operative time 45 minutes or greater plus lithotripsy (p = 0.0004), operative time 45 minutes or greater plus ureteral dilation (p = 0.07) and bilateral stentless procedure (p = 0.005). CONCLUSIONS: Multiple patient and operative factors may predispose a patient to postoperative morbidity after a stentless procedure. Future trials should prospectively validate the role of these factors in either promoting (e.g., history of urolithiasis) or preventing (e.g., preoperative stent) a postoperative complication in the setting of stentless ureteroscopy.

Adult↗
PubMed2002

Ureteroscopy for the treatment of urolithiasis in children.

PURPOSE: Ureteroscopy for treating urolithiasis in prepubertal children has become more common with the advent of smaller instruments. We reviewed our experience with ureteroscopy for urolithiasis in this cohort of patients as well as the literature using this treatment modality in children. MATERIALS AND METHODS: Between 1994 and 2000 we performed 27 ureteroscopic stone extractions in 25 children. Ureteroscopy was done in a manner similar to that in adults. Ureteral dilation was performed when necessary to access the ureter. A stent was placed postoperatively if there was significant ureteral trauma. RESULTS: Of the 25 children 13 were male and 12 were female. Average age was 9.2 years (range 3 to 14). Stones were 2 to 12 mm. in greatest diameter (average 6). Of the 27 procedures the ureteral orifice was dilated before stone treatment in 15 (56%), while in 19 (70%) a stent was placed afterward. No intraoperative and 2 postoperative complications were identified. Overall 92% of the children were rendered stone-free after 1 procedure and 100% were stone-free after 2. CONCLUSIONS: Ureteroscopy for urolithiasis in prepubertal children is safe and effective. Routine ureteral dilation and ureteral stent placement are not always necessary in these patients.

Child↗
PubMed2002

Ureteroscopic treatment of renal calculi in morbidly obese patients: a stone-matched comparison.

OBJECTIVES: To report a matched comparison of morbidly obese (MO) patients and normal weight (NW) patients who underwent ureteroscopic (URS) treatment of renal calculi. Shock wave lithotripsy and percutaneous nephrostolithotomy may be precluded in MO patients, and URS treatment offers a minimally invasive alternative. METHODS: We retrospectively reviewed the charts of patients who underwent URS at our institution between 1997 and 2000. Fifty-four patients underwent URS treatment solely for renal calculi. Sixteen MO patients underwent 18 procedures. Thirty-eight NW patients, who underwent 39 procedures, were matched to the MO patients by stone location and size. Stones were categorized by location and size, less than 10 mm or 10 mm or greater. The factors and outcomes assessed were stone length, operative time, presence of a ureteral stent, success, and complications. RESULTS: The overall success rate was 83% (15 of 18 procedures) for MO patients and 67% (26 of 39 procedures) for NW patients, but this difference was not significant (P = 0.23). The difference in the success rate for renal calculi 10 mm or greater (100% versus 38%) approached significance (P = 0.09). This may be related to other distinctions between the groups. URS treatment was often a salvage therapy in the NW group after other modalities failed. No significant differences were found between the other outcomes. CONCLUSIONS: URS treatment of renal calculi when matched for location and size is as successful and no more morbid in MO than in NW patients. URS treatment of renal calculi is a safe and effective first-line treatment for renal calculi in MO patients.

Body Mass Index↗
PubMed2002

Diagnosis and treatment of ejaculatory dysfunction.

The normal ejaculatory process requires complex coordination and integration of neurologic, physiologic, anatomic, and psychologic events. An understanding of these processes is critical to evaluate properly and manage patients with ejaculatory dysfunction. With the advent of improved techniques to treat patients, some men with ejaculatory dysfunction are being offered the opportunity to reproduce. Further research on the ejaculatory process and associated dysfunctional states should continue to improve treatment for patients presenting with ejaculatory disorders.

Ejaculation↗
PubMed2002

Ureteroscopic treatment of lower pole calculi: comparison of lithotripsy in situ and after displacement.

PURPOSE: Ureteroscopic management is a viable option for lower pole calculi less than 2 cm. Recently a technique was described to displace the calculus into a more accessible calix using a nitinol basket or grasper before lithotripsy. We compared the efficacy and safety of this technique with in situ treatment of small and intermediate lower pole calculi. MATERIALS AND METHODS: We retrospectively reviewed the records of 95 ureteroscopy cases performed at our institution from January 1997 through August 2001 for renal calculi located only in the lower pole. Preoperative patient characteristics, stone size, operative details, complications and outcomes were compared for calculi treated in situ and those displaced before treatment. RESULTS: Adequate followup was available on 78 patients. Patients in the displacement group were statistically older, more often had a preoperative indwelling ureteral stent and had a mean operative time that was 16 minutes longer (p = 0.04). Average stone diameter in the in situ and displacement groups was 8 and 10.3 mm., respectively (p = 0.04). In patients with radiographic followup greater than 1 month complete success was obtained for 77% of stones 1 cm. or less treated in situ versus 89% treated with displacement first (p = 0.43). For calculi greater than 1 cm. complete success was obtained for 2 of the 7 (29%) treated in situ versus all 7 (100%) treated with displacement (p = 0.005). CONCLUSIONS: When treating lower pole calculi 1 to 2 cm. via ureteroscopy, a higher success rate can be obtained with displacement into a more accessible calix before treatment.

Adult↗
PubMedDate not supplied

Isolation of motile spermatozoa from semen samples using microfluidics.

A microfluidic device was designed with two parallel laminar flow channels where non-motile spermatozoa and debris would flow along their initial streamlines and exit one outlet, whereas motile spermatozoa had an opportunity to swim into a parallel stream and exit a separate outlet. Motile sperm samples were prepared with density gradient separation (n = 5). Sperm motility was assessed the following day after exposing aliquots to polydimethylsiloxane (PDMS) used to construct the device. There was no difference in sperm motility when compared with unexposed aliquots (P > 0.05). Unprocessed semen samples (n = 10) were placed in wider channels and sperm motility and strict morphology were assessed from sorted outlets. Sperm motility increased from 44 +/- 4.5% to 98 +/- 0.4% (P < 0.05) and morphology increased from 10 +/- 1.05% to 22 +/- 3.3% (P < 0.05) following processing. Finally, density gradient prepared samples (n = 6) containing 5 x 10(6) motile spermatozoa/ml and 50 x 10(6) round immature germ cells/ml were sorted and assessed in a similar fashion. The ratio of motile spermatozoa to round immature germ cells in the wide inlet (1:10) was significantly improved in the thin outlet (33:1) (P < 0.05). This microfluidic device provides a novel method for isolating motile, morphologically normal spermatozoa from semen samples without centrifugation. This technology may prove useful in isolating motile spermatozoa from oligozoospermic samples, even with high amounts of non-motile gamete and/or non-gamete cell contamination. A movie sequence showing streaming and sorting of spermatozoa may be purchased for viewing on the internet at www.rbmonline.com/Article/847 (free to web subscribers).

Cell Separation↗