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Biomedical subjects

N L Brackett

Publications and source records attributed to N L Brackett.

At least 19 recordsLinked to original sources
PubMed2001

Reflexes and somatic responses as predictors of ejaculation by penile vibratory stimulation in men with spinal cord injury.

STUDY DESIGN: Retrospective chart review. OBJECTIVE: To identify factors in addition to level of injury (LOI) that may predict ejaculation by penile vibratory stimulation (PVS) in spinal cord injured males. SETTING: Major urban medical school and teaching hospital. MATERIALS AND METHODS: Presence of a bulbocavernosus response (BCR) and a hip flexor response (HR) before PVS (n=123 patients), and somatic responses during PVS (n=204 trials performed on a subset of 44 patients) were evaluated for their frequency of occurrence on trials with and without ejaculation. RESULTS: Overall ejaculation success rates for cervical, T1-T6, and T7-T12 LOI were 71%, 73%, and 35%, respectively. Eighty per cent of patients who were positive for both BCR and HR ejaculated with PVS, while only 8% of patients who were negative for both BCR and HR ejaculated with PVS. For cervical injuries, BCR and HR were no more predictive of ejaculation by PVS than LOI alone. T1-T6 patients were more likely to ejaculate when at least one reflex was present. T7-T12 patients with no BCR were unlikely to ejaculate by PVS. Except for abdominal contractions, somatic responses were not present in the majority of PVS trials. When they were present, however, they occurred in a high percentage of ejaculation trials: withdrawal response (hip flexion, knee flexion and thigh adduction) (90%), piloerection (84%), extremity spasms (83%), thigh abduction (80%), and thigh adduction (72%). CONCLUSION: We recommend that patients with cervical injuries initially undergo PVS. Patients with T1-T6 LOI with at least one reflex present, and patients with T7-T12 LOI with both reflexes, or only BCR present, may undergo PVS. Certain somatic/autonomic responses, when seen, may help in deciding whether to continue with a given trial, or give a repeat trial, of PVS. SPONSORSHIP: The Miami Project to Cure Paralysis and the State of Florida Specific Appropriations.

Adult↗
PubMed2000

Anesthetic block of the dorsal penile nerve inhibits vibratory-induced ejaculation in men with spinal cord injuries.

OBJECTIVES: [corrected] We investigated which nerve pathways are necessary to achieve ejaculation using penile vibratory stimulation (PVS) in men with spinal cord injury (SCI). METHODS: Eight men with SCI were selected based on the presence of a bulbocavernosus reflex (BCR) and consistent antegrade ejaculation with PVS. Level of injury was cervical (4), upper thoracic (4), and lower thoracic (1). Mean age was 30.4 years (range 22 to 38). Usual responses to PVS included autonomic dysreflexia (4), erection (4), and consistent somatic responses such as abdominal contractions (8). Local anesthesia of the dorsal penile nerves (penile block) was achieved using 1% plain lidocaine injection. Effective penile block was confirmed by loss of the BCR. Two PVS ejaculation trials were performed: one trial during the penile block and one trial when the penile block had worn off. In 4 subjects, the bladder contents were analyzed for retrograde ejaculation. RESULTS: With the penile block, ejaculation was inhibited in 100% of the subjects. None of the bladder washings demonstrated sperm, indicating absence of retrograde ejaculation. None of the subjects exhibited their usual erectile response, somatic responses, or signs of autonomic dysreflexia. After the penile block wore off, PVS induced ejaculation in all subjects. If subjects usually had erection, somatic responses, or signs of autonomic dysreflexia, these also returned. CONCLUSIONS: Our data suggest that ejaculatory response to PVS in SCI men requires the presence of intact dorsal penile nerves.

Ejaculation↗
PubMed2000

Sperm motility from the vas deferens of spinal cord injured men is higher than from the ejaculate.

PURPOSE: Recent evidence suggests that the seminal plasma of spinal cord injured men contributes to their distinctive semen profile of normal sperm concentration but low sperm motility and viability. This finding indicates that sperm in these men may be normal before exposure to the seminal and prostatic fluids. To investigate this question we compared vas aspirated to ejaculated sperm in 12 men with spinal cord injury and 14 healthy, age matched controls. MATERIALS AND METHODS: Ejaculate was collected by penile vibratory stimulation or electroejaculation in spinal cord injured men and by masturbation in controls. Sperm was aspirated via microsurgery from 1 hemisectioned vas deferens in spinal cord injured men and during routine elective vasectomy in controls. Ejaculated and aspirated specimens were compared. RESULTS: In men with spinal cord injury mean vas aspirated sperm motility and viability plus or minus standard error of mean were significantly higher than mean ejaculated sperm motility and viability (54.4% +/- 5.0% and 74.1% +/- 5.3% versus 14.1% +/- 2.6% and 26.1% +/- 4.9%, respectively). In controls mean vas aspirated sperm motility and viability were not significantly different from mean ejaculated sperm motility and viability (77.5% +/- 5.2% and 88.9% +/- 2.5% versus 74.3% +/- 5.2% and 85.0% +/- 3.5%, respectively). CONCLUSIONS: In spinal cord injured men sperm motility and viability were significantly higher before contact with seminal fluids. Although aspirated sperm from men with spinal cord injury generally had lower motility and viability than that of controls, implying that epididymal or testicular factors may also have a part, the greatest decrease was observed in the ejaculate. Further study of infertility in these men should focus on prostatic and seminal vesicle factors.

Adult↗
PubMed1999

Serum and semen prostate specific antigen concentrations are different in young spinal cord injured men compared to normal controls.

PURPOSE: Recent investigations have indicated that factors within the seminal plasma may contribute to the condition of low sperm motility in men with spinal cord injury. To determine whether the prostate gland functions normally in these men we chose prostate specific antigen (PSA) as a marker of prostatic function, and compared serum and semen concentrations in spinal cord injured and healthy noninjured men. MATERIALS AND METHODS: The study included 21 spinal cord injured men (mean age 33.3+/-1.2 years) and 22 noninjured normal men (mean age 30.3+/-1.5 years). Blood was obtained from subjects following at least 24 hours of abstinence from ejaculation and serum PSA was determined by modified enzyme immunoassay. Antegrade ejaculates from all subjects were frozen to -80 C, exactly 15 minutes after collection. Seminal plasma PSA was determined using Hybritech Tandem MP assay. RESULTS: Mean serum PSA concentration was 1.20+/-0.19 ng./ml. in spinal cord injured and 0.69+/-0.07 ng./ml. in noninjured men (p<0.02). Mean seminal plasma PSA concentration was 0.59+/-0.11 mg./ml. in spinal cord injured and 1.29+/-0.15 mg./ml. in noninjured men (p<0.001). CONCLUSIONS: Our findings of elevated serum and decreased seminal plasma PSA concentrations indicate that prostatic secretory dysfunction is present in men with spinal cord injury.

Adult↗
PubMed1998

Semen quality in spinal cord injured men: does it progressively decline postinjury?

OBJECTIVE: To determine if semen quality of men with spinal cord injury (SCI) undergoes a progressive decline as a function of years postinjury. DESIGN: A retrospective analysis of cross-sectional data. SETTING: University-based research center. SUBJECTS: Semen quality was examined in 638 specimens from 125 men with SCI. INTERVENTION: Penile vibratory stimulation, electroejaculation, and masturbation were used as semen retrieval methods. Routine semen analysis was performed to evaluate semen quality. MAIN OUTCOME MEASURES: Sperm concentration, total sperm count, and percent sperm motility were examined at 2-year intervals from men whose injuries had occurred 6 weeks to 26 years earlier. RESULTS: No difference in any semen parameter was found as a function of time postinjury. CONCLUSIONS: Semen quality in men with SCI does not progressively decline after the SCI. Men with SCI who are considering biologic fatherhood should be advised that the number of years after injury need not be a determinant in deciding when to start a family.

Adolescent↗
PubMed1998

An analysis of 653 trials of penile vibratory stimulation in men with spinal cord injury.

PURPOSE: We evaluated ejaculatory response and semen quality in 653 trials of penile vibratory stimulation in 211 men with spinal cord injury, and compared results with low versus high amplitude vibratory stimulation. MATERIALS AND METHODS: Low and/or high amplitude penile vibratory stimulation was performed 1 to 27 times in each patient, and antegrade and retrograde specimens of those who ejaculated were analyzed. RESULTS: Significantly more patients ejaculated using high (54.5%) versus low (39.9%) amplitude stimulation. Using either amplitude the ejaculatory success rate was highest in men with injuries at C3 to C7, followed by T1 to T5, T6 to T10 and T11 to L3. While high amplitude stimulation increased the ejaculatory success rate in each group, the highest rate occurred in men with injuries at C3 to C7 (65.6%). Ejaculation was reliable, since most men who ejaculated did so during 100% of the trials and within 2 minutes of stimulation onset. Symptoms of autonomic dysreflexia were safely managed with nifedipine. All patients who ejaculated produced antegrade specimens. With the exception of ejaculate volume, which was significantly higher with high versus low amplitude stimulation, semen parameters were similar using both vibrator amplitudes. CONCLUSIONS: Ejaculatory success is better while semen quality is similar using high versus low amplitude penile vibratory stimulation in men with spinal cord injury. This method may be considered first line treatment for anejaculation in men with spinal cord injury due to its safety, relative effectiveness, and relatively low investment of time and money.

Adult↗
PubMed1998

Predictors of necrospermia in men with spinal cord injury.

PURPOSE: We identify predictors of the lowest yield of dead sperm in ejaculates of men with spinal cord injury. MATERIALS AND METHODS: The percentages of dead immotile sperm and dead total sperm were compared in 141 spinal cord injured and 52 normal men. Predictors of necrospermia investigated in spinal cord injured men included specimen collection by vibratory stimulation versus electroejaculation, residence of sperm in antegrade versus retrograde specimens and level of injury. RESULTS: Spinal cord injured subjects had a significantly higher percentage of dead sperm in the immotile fraction and total specimen than control subjects. The percentage of dead sperm was lower in antegrade versus retrograde specimens and in specimens produced by vibratory stimulation versus electroejaculation. There was no difference in the percentage of dead sperm by level of injury. CONCLUSIONS: Of the parameters evaluated only method and type of specimen collection were predictive of the degree of necrospermia in men with spinal cord injury. Level of injury was not predictive. The ratio of dead-to-live immotile sperm in spinal cord injured men was double that in normal men, indicating a pathological mechanism for sperm cell death.

Adolescent↗
PubMed1997

Seminal reactive oxygen species and sperm motility and morphology in men with spinal cord injury.

OBJECTIVE: To assess the generation of reactive oxygen species and its relation to semen characteristics in men with spinal cord injury. DESIGN: Cross-sectional study. SETTING: Andrology laboratory at a tertiary care facility and research laboratory at a major medical center. PATIENT(S): Men with spinal cord injury and normal men. INTERVENTION(S): Collecting ejaculates from men with spinal cord injury by electroejaculation and vibratory stimulation and from normal men by masturbation. MAIN OUTCOME MEASURE(S): Measurement of reactive oxygen species before and after stimulation with 50 microM N-formyl-methionyl-leucylphenylalanine (FMLP) and 100 nM 12-myristate 13-acetate phorbol ester (PMA), white blood cell (WBC) concentration, sperm motility and morphology, and ejaculation method. RESULT(S): Compared with controls, levels of reactive oxygen species in men with spinal cord injury were significantly higher in unstimulated, f-MLP-stimulated, and PMA-stimulated specimens. The WBC concentration was significantly elevated in patients with spinal cord injury. Sperm motility in men with spinal cord injury was inversely related to the level of reactive oxygen species. The percentage of morphologically normal spermatozoa was significantly lower in men with spinal cord injury. Levels of seminal reactive oxygen species did not differ when comparing specimen type (antegrade versus retrograde) or method of ejaculation in men with spinal cord injury. CONCLUSION(S): Men with spinal cord injury had elevated levels of reactive oxygen species in their semen. Levels of reactive oxygen species were negatively correlated with sperm motility. Levels of reactive oxygen species were independent of the method of ejaculation or the type of specimen.

Adult↗
PubMed1997

Semen quality of spinal cord injured men is better when obtained by vibratory stimulation versus electroejaculation.

PURPOSE: Most spinal cord injured men require assisted ejaculation procedures to obtain semen, and the majority can achieve this result by vibratory stimulation or electroejaculation. We determined if semen obtained by vibratory stimulation differed in quality from that obtained by electroejaculation. MATERIALS AND METHODS: Between subjects and within subjects designs were used. Of 77 spinal cord injured men 23 underwent vibratory stimulation only, 44 electroejaculation only and 10 both procedures. Antegrade, retrograde and total ejaculates were analyzed in each subject for total sperm count, percent motile sperm and percent sperm with rapid linear motion. RESULTS: With vibratory stimulation compared to electroejaculation the percent motile sperm and percent sperm with rapid linear motion were significantly greater, whereas total sperm count was similar, in the antegrade specimens and total ejaculates. This finding was true for different groups of subjects as well as within a group of the same subjects. CONCLUSIONS: Semen obtained by vibratory stimulation is of better quality than that obtained by electroejaculation. In medical practices that include assisted ejaculation of spinal cord injured men, we recommend obtaining a specimen by vibratory stimulation. If that method fails electroejaculation should be performed.

Adult↗
PubMed1997

Sperm from spinal cord injured men lose motility faster than sperm from normal men: the effect is exacerbated at body compared to room temperature.

PURPOSE: We investigated if sperm from spinal cord injured men lose motility and viability faster than sperm from normal men, and if there is an effect of temperature on these parameters. MATERIALS AND METHODS: Identical aliquots of fresh antegrade semen from 10 spinal cord injured men and 9 normal controls were stored at room temperature (23C) or body temperature (37C). Sperm motility and viability were measured at 0, 2, 4, 6 and 8 hours after semen collection. RESULTS: Sperm motility, particularly rapid linear motility, decreased faster in specimens from spinal cord injured men compared to normal controls. This effect was exacerbated at 37C. Heat did not affect the degradation of sperm motility in specimens from normal men. The percent of dead sperm in specimens from spinal cord injured men was significantly greater than that in normal men at all time points. However, the rate of cell death was not faster than normal with time or heat. CONCLUSIONS: When using sperm from spinal cord injured men for purposes of insemination or experimentation the rapid loss of motility must be considered, particularly when stored at body temperature.

Cell Survival↗
PubMed1996

Male fertility following spinal cord injury: facts and fiction.

Although most spinal cord injuries (SCIs) occur to males of parenting age, myths abound as to whether men can biologically father children after SCI. Following SCI, most men experience impairments in erectile and ejaculatory function. Semen can be obtained from almost all men with SCI through the use of vibratory or electrical stimulation. Their ejaculates often have normal sperm counts but more immotile sperm than found in men without SCI. This condition does not seem to be caused by lifestyle factors (such as elevated scrotal temperature, ejaculation frequency, and method of bladder management) but may be related to factors within the seminal plasma. Sperm from men with SCI may be used in assisted reproductive techniques to attempt biological fatherhood. Health care providers, including physical therapists, should encourage men with SCI seeking biological fatherhood to be evaluated at a center dedicated to assisting men with SCI in this specialty area.

Body Temperature↗
PubMed1996

Seminal plasma of spinal cord injured men inhibits sperm motility of normal men.

PURPOSE: Seminal plasma was investigated as a contributor to the poor sperm motility of spinal cord injured men. MATERIALS AND METHODS: Seminal plasma of spinal cord injured men was mixed with sperm of normal men and vice versa. Sperm motility was analyzed at 5 and 60 minutes after mixing. RESULTS: At 5 (but not 60) minutes seminal plasma from spinal cord injured men inhibited motility of sperm from normal men. Concomitantly, seminal plasma from normal men improved motility of sperm from spinal cord injured men. CONCLUSIONS: Seminal plasma of spinal cord injured men contributes to poor sperm motility.

Adolescent↗
PubMed1995

Treatment by assisted conception of severe male factor infertility due to spinal cord injury or other neurologic impairment.

PURPOSE: This retrospective study evaluated the pregnancy rates of 23 couples with male factor infertility due to traumatic spinal cord injury (N = 21), multiple sclerosis (N = 1) or transverse myelitis (N = 1). METHODS: Ovulation induction by clomiphene citrate or gonadotropins was used in combination with intrauterine insemination as an initial approach for assisted conception in all but one couple. RESULTS: Six pregnancies occurred in 60 cycles of intrauterine insemination (mean of 2.6 cycles). In this group, the cumulative pregnancy rate was 26%. Six couples who failed after a total of 33 intrauterine insemination cycles (mean of 5.5 cycles), and 1 couple with no previous intrauterine insemination cycles, initiated 10 cycles of in vitro fertilization (mean of 1.4 cycles). In this group, five pregnancies occurred. The pregnancy rate was 71%. CONCLUSION: We conclude that ovulation induction in combination with intrauterine insemination offers an effective initial therapy of severe male factor infertility due to spinal cord injury.

Adult↗
PubMed1994

Endocrine profiles and semen quality of spinal cord injured men.

We characterized endocrine profiles and semen quality in spinal cord injury subjects using noninjured normal and infertile subjects as controls. Compared to normal controls, spinal cord injury subjects had lower serum levels of luteinizing hormone and follicle-stimulating hormone. Subjects with spinal cord injuries between the T8 and T10 levels had a higher incidence of hormone outliers compared to subjects with injuries at other levels. Sperm motility and per cent normal sperm morphology were lower in spinal cord injury subjects compared to normal controls but not to infertile control subjects. Spinal cord injury subjects with elevated follicle-stimulating hormone levels were azoospermic. We conclude that endocrine abnormalities are likely to accompany spinal cord injury but may not be the sole mechanism contributing to impairments in semen quality.

Adult↗
PubMed1986

Midbrain lesions, dopamine and male sexual behavior.

Destruction of the medial preoptic area (MPOA) eliminates mating in male rats and this region is believed to play a major role in the control of male sexual behavior. Efferents from the MPOA pass through and/or terminate in 4 midbrain regions: the dorsolateral tegmentum (DLT), the central gray, and the A9 and A10 areas. The present study reports the effects of bilateral destruction of each of these midbrain regions on brain catecholamines and sexual behavior in male rats. DLT lesions eliminated mating, reproducing the effect of bilateral preoptic lesions. The sexual activity of males with central gray lesions was accelerated in the sense that the mounting rate for these males was significantly faster than for controls and lesioned males ejaculated more frequently and with shorter latencies than did controls. A9 lesions impaired mating--lesioned males mounted at a slower rate and ejaculated less frequently than controls. Males with A10 lesions took longer to re-initiate mating after an ejaculation than controls, but copulation per se (as reflected in mount rate, ejaculation frequency and latency to ejaculate) was not affected by A10 damage. Brain catecholamine levels were not affected by either DLT or central gray lesions. A9 lesions produced a significant depletion in neostriatal dopamine which was highly correlated with mount latency, mount rate, ejaculation latency and ejaculation frequency. A10 lesions produced a significant depletion of dopamine in the nucleus accumbens and cingulate cortex, but these effects were not significantly correlated with any measure of sexual behavior.

Animals↗
PubMed1984

Medial preoptic connections with the midbrain tegmentum are essential for male sexual behavior.

The medial preoptic area appears to play a major role in the control of sexual behavior. Efferents from the medial preoptic area course through the medial forebrain bundle to pass through and/or terminate in the dorsolateral and ventral tegmentum of the midbrain. Bilateral lesions of the dorsolateral tegmentum eliminate mating behavior in male rats, reproducing the effect of bilateral medial preoptic lesions. Sexual behavior is also eliminated when a preoptic lesion on one side of the brain is combined with a lesion of the dorsolateral tegmentum on the other side of the brain. In other words, asymmetric brain damage which bilaterally destroys the preoptic connections with the dorsolateral tegmentum eliminates male sexual behavior, and we conclude that the connections between these two regions are essential for copulation.

Animals↗
PubMed1980

Calcium-dependent protein kinase: widespread occurrence in various tissues and phyla of the animal kingdom and comparison of effects of phospholipid, calmodulin, and trifluoperazine.

A widespread occurrence of Ca2+-dependent protein kinase was shown in various tissues and phyla of the animal kingdom. Phosphatidylserine appeared to be more effective than calmodulin in supporting the Ca2+-dependent phosphotransferase activity. The phospholipid-sensitive Ca2+-dependent protein kinase activity, distributed in both the cytosolic and particulate fractions, was not inhibited by trifluoperazine, a specific inhibitor of calmodulin-sensitive, Ca2+-dependent reactions or processes. The enzyme activity levels, compared to those of cyclic AMP-dependent and cyclic GMP-dependent protein kinases, were exceedingly high in certain tissues (such as brain and spleen) and exhibited a much greater disparity among tissues. The Ka for Ca2+ was about 100 microM in the presence of phosphatidylserine; the value was as low as 2 microM in the presence of phosphatidylserine and diolein. It is suggested that phospholipid-sensitive Ca2+-dependent protein kinase may mediate certain actions of Ca2+ in tissues, acting independently or in a complementary manner with other protein phosphorylation systems stimulated by calmodulin-Ca2+, cyclic AMP, or cyclic GMP.

Animals↗