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Biomedical subjects

Dana A Ohl

Publications and source records attributed to Dana A Ohl.

At least 19 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

Clinical hypogonadism and androgen replacement therapy: an overview.

Testosterone has a complex variety of roles in male physiology. It is a common belief that testosterone in men declines with age. While this is true, there are several aspects to this decline which make it difficult to diagnose definitively, as other endocrine components can contribute to a patient's symptoms. There are some guidelines to help determine when to begin treatment, based on laboratory assays and symptomatology. Testosterone replacement in men can improve overall quality of life, can reverse some of the effects of hypogonadism, and can be done very safely with available pharmacologic agents.

Aftercare↗
PubMed2005

IVF within microfluidic channels requires lower total numbers and lower concentrations of sperm.

BACKGROUND: Microfluidic technology has been utilized in numerous biological applications specifically for miniaturization and simplification of laboratory techniques. We sought to apply microfluidic technology to murine IVF. METHODS: Microfluidic devices measuring 500 microm wide, 180 microm deep, and 2.25 cm in length were designed and fabricated using poly(dimethylsiloxane) (PDMS). Controls were standard centre-well culture dishes with 500 microl of media, half of which also contained PDMS as a material control. Denuded mouse oocytes were placed into microchannels or centre-well dish controls in groups of 10, then co-incubated overnight with epididymal mouse sperm at various concentrations. Fertilization was assessed and Fisher's exact test was used for statistical analysis (P < 0.05 significant). RESULTS: Fertilization rates between the two control groups (42%, no PDMS; 41%, with PDMS; not significant) were similar. Fertilization rates for denuded oocytes at standard mouse insemination sperm concentration (1 degrees 10(6) sperm/ml) was poorer in microchannels (12%) than controls (43%; P < 0.001). As insemination concentrations decreased, fertilization rates improved in microchannels with a plateau between 8 degrees 10(4) and 2 degrees 10(4) sperm/ml (4000-1000 total sperm). At these concentrations, combined fertilization rate for denuded oocytes was significantly higher in microchannels than centre-well dishes (27 versus 10%, respectively; P < 0.001), and was not significantly different from corresponding controls with a sperm concentration of 1 degrees 10(6) (37%; P = 0.06). CONCLUSIONS: Murine IVF can be conducted successfully within microfluidic channels. Lower total numbers and concentrations of sperm are required. Microfluidic devices may ultimately be useful in clinical IVF.

Animals↗
PubMed2004

Endogenous regulators of protein phosphatase-1 during mouse oocyte development and meiosis.

Reversible phosphorylation, involving protein kinases and phosphatases (PP), is important in regulating oocyte meiosis. Okadaic acid (OA) inhibition of PP1 and/or PP2A stimulates oocyte germinal vesicle breakdown (GVB). In oocytes, PP1 is localized in the cytoplasm and nucleus, yet endogenous regulation of oocyte PP1 has not been investigated. The objectives of the study were to identify intra-oocyte mechanisms regulating PP1 during acquisition of OA-sensitive meiotic competence and meiotic resumption. Immunohistochemical studies revealed that GVB-incompetent oocytes contained equivalent cytoplasmic and nuclear PP1. Upon development of OA-sensitive meiotic competence, PP1 displayed differential intracellular localization with significantly greater nuclear staining with distinct nucleolar rimming compared with cytoplasmic staining. Germinal vesicle-intact oocytes contained neither nuclear inhibitor of PP1, nor PP1 cytoplasmic inhibitor-1 transcripts or proteins. Reverse transcription-PCR with PP1 cytoplasmic inhibitor-2 (I2) primers and oocyte RNA amplified a predicted 330-bp product with the identical sequence to mouse liver I2. Oocytes contained a heat-stable PP1 inhibitor with biochemical properties of I2. Phosphorylation of PP1 at Thr320 by cyclin dependent kinase-1 (CDK1) causes PP1 inactivation. Germinal vesicle-intact oocytes did not contain phospho-Thr320-PP1. Upon GVB, PP1 became phosphorylated at Thr320 and this phosphorylation did not occur if GVB was blocked with the CDK1 inhibitor, roscovitine (ROSC). Inhibition of oocyte GVB with ROSC was reversible and coincided with PP1 phosphorylation at Thr320. Increased oocyte staining of nuclear PP1 compared with cytoplasmic staining at a chronological stage when oocytes gain meiotic competence, and phosphorylation and inhibition of PP1 by CDK1 at or around GVB appear to be important mechanisms in regulating oocyte PP1 activity and meiosis. In addition, these studies provide further support for PP1 being the OA-sensitive PP important in the regulation of the acquisition of meiotic competence, nuclear events during meiotic arrest, and GVB.

Animals↗
PubMed2003

Glycogen synthase kinase-3 regulates mouse oocyte homologue segregation.

Intracellular regulation of oocyte meiosis is not completely understood. However, reversible phosphorylation, which involves serine/threonine protein kinases and phosphatases (PP), is an important mediator. Glycogen synthase kinase-3 (GSK-3) is a highly conserved serine/threonine protein kinase. Currently no reports exist on presence or function of GSK-3 in mammalian oocytes. The aim of this study was to determine GSK-3 presence/absence, transcript and protein expression, intracellular protein distribution, and to investigate the functional importance of GSK-3 in mouse oocyte meiosis. Germinal vesicle-intact (GVI) oocytes contained both GSK-3 transcript and protein. Although GSK-3 beta-isoform is the only transcript identifiable in GVI oocytes, both alpha- and beta-isoforms were recognized by Western blot analysis. In growing, meiotic-incompetent oocytes GSK-3 was present, diffusely located throughout the cytoplasm and absent in the nucleus, whereas in meiotic-competent oocytes this cytoplasmic GSK-3 displays a predominant peri-oolemma staining. Treatment of mouse GVI oocytes with lithium chloride (LiCl), which inhibits both inositol monophosphatase (IMPase) and GSK-3, had no significant influence on oocyte viability, morphology, or development to metaphase II (MII). However, LiCl caused abnormal spindle formation and significantly increased incidence of abnormal homologue segregation during the first meiotic division. L690,330, which is a specific IMPase inhibitor, had no significant effect on oocyte viability, morphology, MII development, or homologue segregation. This is the first report of GSK-3 in mammalian oocytes. LiCl inhibition of mouse oocyte GSK-3 modified organization of microtubules and/or function of meiotic spindles thus compromising segregation of condensed bivalent chromosomes.

Animals↗
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

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

Effects of ejaculation by penile vibratory stimulation on bladder capacity in men with spinal cord lesions.

PURPOSE: We examined the effects of ejaculation by penile vibratory stimulation on bladder capacity in men with spinal cord lesions. MATERIAL AND METHODS: Included in our study were 14 men with spinal cord lesions from C4 to T7 with detrusor hyperreflexia. Cystometry was performed before and immediately after ejaculation by penile vibratory stimulation to establish baseline conditions and repeated after 1 month of ejaculation by penile vibratory stimulation every third day. The third cystometry study was done after 1 month of ejaculation by penile vibratory stimulation every third day at home to determine any long-term effects of treatment. This third cystometry was performed 72 hours after the last ejaculation to exclude any acute effects of ejaculation by penile vibratory stimulation on detrusor hyperreflexia. In addition, 1 to 3 days later ejaculation was induced by penile vibratory stimulation and immediately followed by cystometry to examine whether it was possible to achieve an acute effect as well as a potential long-term effect. RESULTS: Baseline urodynamic investigations revealed bladder hyperreflexia and external sphincter dyssynergia in all individuals. There was no statistically significant difference in bladder capacity at leak point before and immediately after ejaculation by penile vibratory stimulation. However, after 4 weeks of frequent penile vibratory stimulation treatment bladder capacity at leak point increased significantly from a median of 190 ml. (range 17 to 700) at baseline to 293 (range 30 to 700) (Wilcoxon signed rank test p = 0.03). Furthermore, there was a trend toward decreased intravesical pressure during the filling phase. CONCLUSIONS: Ejaculation by penile vibratory stimulation was associated with a significant increase in bladder capacity at leak point after 4 weeks of frequent treatment. This finding may have implications in the management of incontinence in men with spinal cord lesions.

Adult↗
PubMed2003

Artificial urinary sphincter, Part I: Overview.

Urinary incontinence has a tremendous impact on an individual's quality of life and self-esteem. A number of patients will fail both conservative medical as well as conservative surgical treatments in their pursuit to regain urinary control. The surgical implantation of an artificial urinary sphincter (AUS) is a definitive surgical option to reestablish continence. However, there are many challenges that may arise as a patient progresses through the rigorous preparation, surgical procedure, and recovery process. Understanding the history, various indications, and risks of AUS surgery will aid in counseling patients considering AUS.

Humans↗
PubMed2003

Artificial urinary sphincter, Part II: Patient teaching and perioperative care.

As discussed in Part I, effective management of urinary incontinence is a tremendous quality of life intervention. The surgical implantation of an artificial urinary sphincter (AUS) provides a definitive, although invasive, surgical option to re-establish continence. Understanding the intraoperative surgical procedure, postoperative care, and teaching will aid in preparing patients undergoing AUS implantation for successful outcomes.

Aftercare↗
PubMed2002

Processed total motile sperm count correlates with pregnancy outcome after intrauterine insemination.

OBJECTIVES: To determine the impact of processed total motile sperm (PTMS) count on pregnancy after partner intrauterine insemination (IUI). IUI is generally attempted before proceeding to more expensive and invasive assisted-reproductive techniques such as intracytoplasmic sperm injection. Several semen parameters have been shown to correlate with IUI outcome and may be useful when counseling couples. METHODS: Four hundred thirty-eight couples with diverse causes of infertility underwent 1114 cycles of husband IUI during a 39-month period. The clinical and semen parameters were recorded for each couple and each insemination. The parameters were compared between those couples who achieved a pregnancy and those who did not. RESULTS: The total number of pregnancies was 120, resulting in a pregnancy rate per cycle of 10.8% and a couple pregnancy rate of 27.4%. On multivariable logistic regression analysis, the PTMS count was independently associated with fertility after IUI (P = 0.0014). Moreover, the pregnancy rate was significantly lower for couples with less than 10 million PTMS (P <0.05). CONCLUSIONS: The results of this study have demonstrated that the PTMS count independently predicts success with IUI. Cycles with less than 10 million total motile sperm are significantly less likely to result in a pregnancy. If cause-specific therapy has failed, alternatives to IUI should be considered for couples when the PTMS count is less than 10 million.

Adult↗
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

The utility of lockout valve reservoirs in preventing autoinflation in penile prostheses.

INTRODUCTION: Autoinflation is a troublesome complication following penile prosthesis placement that may be potentiated by prevesical scarring following radical prostatectomy. We evaluated the frequency of autoinflation and other complications following penile prosthesis placement in radical prostatectomy patients and controls as a surrogate to establishing the utility of lockout reservoirs in preventing autoinflation. METHODS: 139 prostheses (including 14 with lockout reservoirs) were placed in 132 men (including 35 post-prostatectomy patients) over a 5(1/2) year period at our institution. Outcomes assessed include postoperative complications and the need for revision or replacement of the prosthesis. Multivariable regression analysis was used to determine the association of patient, device-specific, and perioperative characteristics with these outcomes. RESULTS: There was no difference in the postoperative complication and re-operation rates between post-prostatectomy patients and controls (both p > 0.77). The incidence of autoinflation in post-prostatectomy patients and controls was 3% and 5%, respectively (p > 0.99). Patients with prior prostheses were 3 times as likely to develop a postoperative complication or require prosthesis revision (p = 0.02). CONCLUSION: Penile prostheses are well tolerated in post-prostatectomy patients with comparable outcomes to those men with organic erectile dysfunction. The frequency of autoinflation does not appear to be increased in post-prostatectomy patients. Initial results with the lockout valve reservoir in preventing autoinflation are encouraging though additional study is warranted to justify their routine use.

Aged↗
PubMed2002

Penile vibratory stimulation and electroejaculation in the treatment of ejaculatory dysfunction.

The purpose of this review is to present the current understanding of penile vibratory stimulation (PVS) and electroejaculation (EEJ) procedures and its clinical use in men with ejaculatory dysfunction. Unfortunately, the record of treating such individuals has been quite poor, but within recent years development and refinement of PVS and EEJ in men with spinal cord injury (SCI) has significantly enhanced the prospects for treatment of ejaculatory dysfunction. The majority of spinal cord injured men are not able to produce antegrade ejaculation by masturbation or sexual stimulation. However, approximately 80% of all spinal cord injured men with an intact ejaculatory reflex arc (above T10) can obtain antegrade ejaculation with PVS. Electroejaculation may be successful in obtaining ejaculate from men with all types of SCI, including men who do not have major components of the ejaculatory reflex arc. Because vibratory stimulation is very simple in use, non-invasive, it does not require anaesthesia and is preferred by the patients when compared with EEJ, PVS is recommended to be the first choice of treatment in spinal cord injured men. Furthermore, EEJ has been successfully used to induce ejaculation in men with multiple sclerosis and diabetic neuropathy. Any other conditions which affect the ejaculatory mechanism of the central and/or peripheral nervous system including surgical nerve injury may be treated successfully with EEJ. Finally, for sperm retrieval and sperm cryopreservation before intensive anticancer therapy in pubertal boys, PVS and EEJ have been successfully performed in patients who failed to obtain ejaculation by masturbation. Nearly all data concerning semen characteristics in men with ejaculatory dysfuntion originate from spinal cord injured men. Semen analyses demonstrate low sperm motility rates in the majority of spinal cord injured men. The data give evidence of a decline in spermatogenesis and motility of ejaculated spermatozoa shortly after (few weeks) an acute SCI. Furthermore, it is suggested that some factors in the seminal plasma and/or disordered storage of spermatozoa in the seminal vesicles are mainly responsible for the impaired semen profiles in men with chronic SCI. Home insemination with semen obtained by penile vibratory and introduced intravaginally in order to achieve successful pregnancies may be an option for some spinal cord injured men and their partners. The majority of men will further enhance their fertility potential when using either penile vibratory or EEJ combined with assisted reproduction techniques such as intrauterine insemination or in-vitro fertilization with or without intracytoplasmic sperm injection.

Ejaculation↗
PubMed2002

Penile prosthesis: patient teaching and perioperative care.

As more options become available for treating erectile dysfunction (ED), more men are seeking treatment. Despite excellent efficacy of available medical management, a percentage of these patients will be refractory to the less invasive options for treatment, leaving the surgical implantation of a penile prosthesis as their remaining option for definitive treatment of ED. The patient seeking penile prosthesis surgery faces many challenges as he proceeds through the perioperative processes. A thorough understanding of indications, preoperative assessment and teaching, intraoperative procedure, and postoperative care and teaching for the patient receiving a penile prosthesis will enable him to achieve the best possible outcome.

Contraindications↗