Clinical immunology of vasectomy and vasovasostomy

Are there susceptibility factors for primary progressive aphasia?

The determinants of selective vulnerability in neurodegenerative diseases remain elusive. The asymmetric loss of neurons in primary progressive aphasia offers a unique setting for addressing this question. Although no factor can yet account for the selective vulnerability of the left hemisphere language network to degenerative diseases, a few themes are emerging as potential targets of further investigation.

Factors predicting overall success: a review of 747 microsurgical vasovasostomies

OBJECTIVES

Advances in surgical techniques have improved the outcome of microsurgical vasovasostomy (VV). We performed a retrospective analysis of surgical procedures to determine outcomes and predictors of VV success, to develop Kaplan-Meier Curves for predicting VV outcomes and to evaluate the use of alpha-glucosidase (AG) to predict outcomes.

PATIENTS AND METHODS

We undertook a retrospective analysis of 747 modified 1-layer microsurgical VV procedures performed between 1984 and 2000. Obstructive interval, partner status, social status preoperatively and method of vasal obstruction, vasal fluid quality and sperm granuloma intraoperatively were compared with outcome results. Parameters evaluated at follow-up included semen analysis, AG concentration in ejaculate fluid and pregnancy rates.

RESULTS

The overall patency rate was 86% and pregnancy rates were 33% and 53% at 1 and 2 years after primary VV, respectively. Preoperative factors associated with successful outcome and pregnancy included shorter obstructive interval and same female partner (p < 0.05). Intraoperative factors predicting success included the use of surgical clips instead of suture at vasectomy, the presence of a sperm granuloma, the presence and quality of vasal fluid, and the presence and quality of sperm in vasal fluid. Further, increased AG in the postoperative semen predicted improved patency and pregnancy outcomes.

CONCLUSION

This study confirms the effectiveness of VV for vasectomized men who wish to father children. It also demonstrates that preoperative and intraoperative factors are predictive of the VV outcome. Postoperative AG is also a useful marker of patency and it appears to predict pregnancy outcome.

Putative health risks associated with vasectomy

Vasectomy is widely regarded as a safe method of contraception, but over the years there have been many reports suggesting putative health risks associated with the procedure. Concerns over the possible association of vasectomy with a number of medical conditions, including cardiovascular disease, testicular cancer, prostate cancer, psychologic distress, and a variety of immune complex-mediated disease processes have been reported. Most recently, a manuscript from the neurology literature has described an association between vasectomy and primary progressive aphasia, a rare variety of frontotemporal dementia. This article reviews the literature surrounding each of these purported health concerns. Because the ultimate findings have important ramifications for both informed consent of vasectomy patients and for public health, the reported health risks in question should be critically evaluated.

Vasectomy in Men With Primary Progressive Aphasia

OBJECTIVE

To study the frequency of vasectomy in men with primary progressive aphasia (PPA).

BACKGROUND

PPA is a dementia syndrome in which aphasia emerges in relative isolation during the initial stages of illness. On the basis of a clinical observation in a patient who dated the onset of symptoms to the period after a vasectomy, and because of the curious sharing of the tau protein exclusively by brain and sperm, vasectomy rates were examined in men with PPA.

METHOD

This study used a case control design. Forty-seven men with PPA and 57 men with no cognitive impairment (NC) between 55 and 80 years of age were surveyed about a history of vasectomy.

RESULTS

The age-adjusted rate of vasectomy in PPA patients (40%) was higher than in NC (16%, P=0.02). There was a younger age at onset for the patients with vasectomy (58.8 vs. 62.9 y, P=0.03).

CONCLUSIONS

Vasectomy may constitute one risk factor for PPA in men. Potential mechanisms mediating risk include vasectomy-induced immune responses to sperm, which shares antigenic epitopes with brain. Antisperm antibodies can also develop in women and become risk factors for PPA.

Effects of vasectomy on spermatogenesis and fertility outcome after testicular sperm extraction combined with ICSI

BACKGROUND

Each year 40,000 men have a vasectomy in the UK whilst another 2400 request a reversal to begin a second family. Sperm can now be obtained by testicular biopsy and subsequently used in assisted conception with ICSI. The study aims were to compare sperm yields of men post-vasectomy or with obstructive azoospermia (OA) of unknown aetiology with yields of fertile men and to assess any alteration in the clinical pregnancy rates after ICSI.

METHODS

Testicular tissue was obtained by Trucut needle from men who had undergone a vasectomy >5 years previously or had OA from other causes and from fertile men during vasectomy. Seminiferous tubules were milked to measure sperm yields. Numbers of Sertoli cells and spermatids and thickness of the seminiferous tubule walls were assessed using quantitative computerized analysis.

RESULTS AND CONCLUSIONS

Sperm yields/g testis were significantly decreased in men post-vasectomy and in men with OA, relative to fertile men. Significant reductions were also observed in early (40%) and mature (29%) spermatid numbers and an increase of 31% was seen in the seminiferous tubule wall (basal membrane and collagen thickness) of vasectomized men compared with fertile men. Clinical pregnancy rates in couples who had had a vasectomy were also significantly reduced.

Effect of time since vasectomy and maternal age on intracytoplasmic sperm injection success in men with obstructive azoospermia after vasectomy

OBJECTIVE

To determine the effects of time since vasectomy and maternal age on intracytoplasmic sperm injection (ICSI) outcome in azoospermic men after vasectomy.

DESIGN

Retrospective analysis.

SETTING

Assisted conception unit.

PATIENT(S)

Thirty-seven azoospermic men (after vasectomy) who were undergoing 56 cycles of ICSI.

INTERVENTION(S)

Surgical sperm retrieval and standard ICSI protocol. The ICSI cycles were analyzed in four groups, according to years since vasectomy, and were reanalyzed in three groups, according to maternal age.

MAIN OUTCOME MEASURE(S)

Fertilization rate, implantation rate, clinical pregnancy rate, and live-birth rate (LBR) per ET.

RESULT(S)

No effect of time since vasectomy was seen on any outcome. The highest fertilization rate and LBR were found in the group with the longest time interval. These findings could not be explained by differences in either patient characteristics or stimulation regimes. When reanalyzed by maternal age, there was an improvement in implantation rate and LBR with decreasing maternal age. Live birth rates of 38.5%, 22.7%, and 11.8% were achieved for maternal ages of <32, 32-37, and >38 years, respectively. Logistic regression confirmed a statistically significant effect on outcome of maternal age but not time since vasectomy.

CONCLUSION(S)

Our data suggest that maternal age, and not interval since vasectomy, remains the principal determinant of ICSI success in men with obstructive azoospermia after vasectomy.

Current practice in the management of vasectomy reversal and unobstructive azoospermia in Merseyside & North Wales: a questionnaire-based survey

OBJECTIVE

To investigate the current incidence of vasectomy reversal procedures, the techniques used and which practitioners use them.

PATIENTS AND METHODS

Using a questionnaire, 130 general surgeons and urologists practising in Merseyside and North Wales were surveyed.

RESULTS

The response rate was 74%, with 24 urological surgeons and 14 general surgeons undertaking vasectomy reversal. Annually, urological surgeons carried out significantly more procedures than did general surgeons, at 8.5 and 5.3 (P = 0.029), respectively. They were also more likely to use double-layer closure and microsurgical techniques, whilst significantly less likely to use stents. Urologists reported significantly greater patency rates, at 76% and 52% (P = 0.017), respectively, with no significant differences in subsequent pregnancy rates (30% vs 25%). Only one practitioner checked tubal patency in the female partner before vasectomy reversal.

CONCLUSIONS

The use of vasectomy reversal is a cost-effective treatment for men wanting paternity after vasectomy. The technique used by the clinician and proper audit of the results require close attention; it would also appear to be obvious that all the partners of men seeking a vasectomy reversal should have their fertility status established before reversal, something that is clearly not done at present.

Male antisperm antibodies: association with a modified sperm stress test and lipid peroxidation

We previously reported a modified sperm stress test (MOST), low scores (< 0.39) in which were associated with sperm-related abnormal in vitro fertilization. Preliminary observations suggested that the presence of male sperm antibodies (ASA) could give low MOST scores. It was therefore decided to undertake a study to verify this possible association and also to ascertain if such a relationship was causal in nature. Six hundred and fifty semen samples from patients consulting for infertility were assessed for basic seminal characteristics, motion parameters (CASA), ASA and MOST. Thirty-nine samples (6%) were ASA-positive. Samples with and without ASA showed similar characteristics, except for percentage of normal forms and MOST scores (0.35 +/- 0.03 vs. 0.67 +/- 0.01, P < 0.001, for ASA-positive and -negative, respectively). There was a strong statistical association between presence of ASA and low MOST scores (P < 0.0001). One-hundred per cent of ASA-positive samples displayed low MOST scores. To verify the nature of this relationship, we incubated ASA-free spermatozoa with ASA-positive and -negative (control) sera. Despite an increase in the percentage of ASA-bearing spermatozoa in those aliquots incubated with ASA-positive serum, their original (pre-incubation) MOST scores remained unchanged. Furthermore, the rate of lipid peroxidation, indirectly reflected in MOST scores, was not different in the aliquots incubated with ASA. In conclusion, there seems to be a strong association between presence of ASA and low MOST values in semen samples of infertile patients; however, the relationship does not appear to be causal.

Predictors of success in microsurgical correction of vasal and epididymal obstruction

Patients who inquire about microsurgical correction of vasal and epididymal obstructions should be informed about the postoperative rates of both return of sperm to the semen and pregnancy. They also should be informed about the possibility of a successful outcome, depending on their individual circumstances. The various preoperative, intraoperative, and postoperative factors that influence success rates are discussed in this article.

Comparison of modified one- and two-layer microsurgical vasovasostomy

OBJECTIVE

To compare the outcome of a modified one-layer and two-layer vasovasotomy (VV) in two groups of similar men undergoing vasectomy reversal.

PATIENTS AND METHODS

The charts and surgical records of all surgical procedures performed on men undergoing a modified one- or two-layer VV between June 1992 and July 1994 were retrospectively reviewed. A successful outcome (patency) was defined as sperm present at follow-up (mean follow-up 8 weeks). A modified one-layer VV was used in 17 men (group 1) and a two-layer VV in 23 (group 2).

RESULTS

Sperm were present in both groups if surgery was undertaken after vasal obstruction lasting < 36 months. The modified one- and two-layer VV had equal patency (88% and 90%, respectively) when undertaken after an obstructed interval of 36-96 months; outcomes were poorer if surgery was performed after > 96 months. The mean operative duration was 96 min for a modified one-layer VV and 167 min for the two-layer VV.

CONCLUSIONS

The simpler and faster modified one-layer VV provides sufficient accuracy for successful vasectomy reversal in most cases. For most patients, both procedures have equivalent patency.

Safety and effectiveness of vasectomy

OBJECTIVE

To recommend further research on vasectomy based on a systematic review of the effectiveness and safety of vasectomy.

DESIGN

A systematic MEDLINE review of the literature on the safety and effectiveness of vasectomy between 1964 and 1998.

MAIN OUTCOME MEASURE(S)

Early failure rates are <1%; however, effectiveness and complications vary with experience of surgeons and surgical technique. Early complications, including hematoma, infection, sperm granulomas, epididymitis-orchitis, and congestive epididymitis, occur in 1%-6% of men undergoing vasectomy. Incidence of epididymal pain is poorly documented. Animal and human data indicate that vasectomy does not increase atherosclerosis and that increases in circulating immune complexes after vasectomy are transient in men with vasectomies. The weight of the evidence regarding prostate and testicular cancer suggests that men with vasectomy are not at increased risk of these cancers.

CONCLUSION(S)

Publications to date continue to support the conclusion that vasectomy is a highly effective form of contraception. Future studies should include evaluations of the long-term effectiveness of vasectomy, evaluating criteria for postvasectomy discontinuation of alternative contraception for use in settings where semen analysis is not practical, and characterizing complications including chronic epididymal pain syndrome.

Antisperm autoantibody response is reduced by early repair of a severed vas deferens in the juvenile rat

OBJECTIVE

To determine whether antisperm autoantibody production after prepubertal vas injury is influenced by immediate repair of the vas compared to delay of the reanastomosis until sexual maturity.

DESIGN

Animal study comparing early repair, late repair, and sham-operated groups.

SETTING

Research laboratory in a medical school.

PATIENT(S)

Lewis rats.

INTERVENTION(S)

After division of the vas deferens in juvenile rats, animals in an early repair group had the vasa repaired immediately by using an absorbable intraluminal stent. Animals in a late repair group had vasa obstructed by ligation until after puberty, when they underwent microsurgical vasovasostomy (age 60 days).

MAIN OUTCOME MEASURE(S)

Antisperm antibodies were assayed by ELISA. The weights of reproductive organs were determined, and samples of testis were studied by light microscopy.

RESULT(S)

The antisperm antibody response was less when the vas was repaired immediately than if the repair was delayed until after puberty. There was a low incidence of testicular alteration in the repair groups and none in sham-operated animals.

CONCLUSION(S)

If the vas deferens is injured or obstructed prepubertally, there may be a benefit to considering immediate repair to reduce the likelihood of developing antisperm autoantibodies, which have been associated with reduced fertility.

Antisperm antibodies: etiology, pathogenesis, diagnosis, and treatment

OBJECTIVE

To critically review the English-language literature and describe the current diagnosis, prevalence, etiology, and treatment of antisperm antibodies (ASA).

DESIGN

A comprehensive literature search of the English-language literature published between 1966 and December 1997 was performed on MEDLINE. Articles were also located via bibliographies of published works.

RESULT(S)

Data were excerpted from articles identified by MEDLINE search. The diagnosis, prevalence, etiology, and treatment of ASA are described.

CONCLUSION(S)

There is sufficient evidence that ASA impair fertility in couples with unexplained infertility. A number of different methodologies are available, which may be used in their detection. However, in many cases, test interpretation is subjective. Although there is not enough evidence to support systemic treatment for ASA, application of a variety of assisted reproductive technologies improves outcome.

Vasectomy is associated with an increased risk for urolithiasis

We evaluated vasectomy as a potential risk factor for urolithiasis. Vasectomy is a common method of contraception among otherwise healthy men. This is also the population at highest risk for urolithiasis. We conducted a case-control study of patients in a large prepaid health maintenance organization. Cases were men experiencing initial episodes of urolithiasis, ascertained by reviewing radiology logs and medical records. The age-matched controls were men with no history of urolithiasis. In logistic regression models, the relative risk of urolithiasis for men with vasectomies compared with men without vasectomies was 1.9 for men younger than 46 years of age (95% confidence interval = 1.2 to 3.1, P = 0.005), and the relative risk was 0.9 (95% confidence interval = 0.5 to 1.5, P > 0.8) for men who were at least 46 years old. The relative risk of urinary calculi was 2.0 (95% confidence interval 1.0 to 4.1, P < 0.05) for men with vasectomies 0 to 4 years before evaluation compared with men without vasectomies, and the excess risk persisted as long as 14 years postvasectomy. Vasectomy was associated with a twofold increased risk for urolithiasis in men younger than 46 years of age. This increased risk may persist for up to 14 years postvasectomy. Given the large number of men who undergo vasectomy worldwide each year, the increased risk for urolithiasis among vasectomized men may result in substantial excess morbidity.

Microsurgical correction of posttesticular obstruction. Peroperative findings and postoperative semen quality

Exploration for microsurgical reconstruction of the vas deferens or its epididymal junction was performed in 47 consecutively treated men. Epididymovasostomy was planned in 27 cases. Malformation was found in five and Young's syndrome in nine, and most of the others had a history of urogenital infections. Reconstruction was accomplished in 17 cases. Nine were azoospermic preoperatively. Four (three with Young's syndrome/malformation) remained so, whereas patency was demonstrated in four and one did not supply a semen specimen postoperatively. Eight had severe unexplained oligozoospermia preoperatively, and in four of them the sperm counts normalized postoperatively while the other four remained oligozoospermic. In no case did preoperative oligozoospermia progress to azoospermia postoperatively. Complete normalization of all spermiogram parameters occurred in only two cases after epididymovasostomy. Of the 20 who underwent reversal of vasectomy, 17 provided semen for postoperative testing. 16/17 specimens contained spermatozoa, but spermiograms, including penetration tests, were completely normal in only three cases. This study indicates a discrepancy between good patency and good semen quality. Our study also suggests that some men with unexplained severe oligozoospermia are as likely to benefit from epididymovasostomy as are azoospermic men.

Effects of vasectomy on the epididymis

Common principles can be discerned in the response of the epididymis to vasectomy, despite species differences. Increases in the size and number of lysosomes are the most frequent changes in the epididymal epithelium. The presence or absence of additional alterations such as changes in the height of the epithelium may be related to variations in distensibility of the vas deferens and epididymis. Direct measurements by micropuncture of epididymal and seminiferous tubule hydrostatic pressure indicate that, contrary to dogma, increased pressure in the distal epididymis after vasectomy is not generally transmitted to the seminiferous tubules. The epididymal interstitium shows microscopic changes indicative of chronic inflammation, with infiltration of macrophages, lymphocytes, and plasma cells, and rats with these lesions have higher antisperm antibody levels than animals lacking epididymal changes. Macrophages and neutrophils may enter the duct through the epididymal epithelium, at sites of rupture of the duct, and in the efferent ductules. Cyst-like spermatic granulomas occur in virtually all species where the epididymis or vas deferens ruptures with escape of spermatozoa. The sites and timing of granuloma formation may depend on the mechanical properties of the tract in different species, and they are probably important in the immune response to vasectomy. Postvasectomy sera in Lewis rats recognize a consensus repertoire of dominant autoantigens that closely resembles the antigens bound by sera from rats immunized with isologous spermatozoa. There are multiple routes for disposal of the sperm that continue to be produced after vasectomy.

Risk factors for antisperm antibodies in infertile men

PROBLEM

The prevalence of anti-sperm antibodies (ASAs) in the general population is 0 to 2%; the prevalence in infertile men is much higher at 7 to 26%. However, the role of ASAs in male infertility remains controversial to date. Although several risk factors for ASA development have been defined (such as testicular torsion, varicocele, cryptorchidism, vasectomy, and genital tract infection), there are no specific indications for ASA testing.

METHOD

In order to examine if a single parameter exists identifying patients with elevated ASA titers, serum ASA testing was performed with an enzyme-linked immunosorbent assay (ELISA) in 226 consecutive male patients. The new assay, synchron ELISA (Synelisa) used in our study represents a new type of ELISA without fixation of the sperm surface antigens by formaldehyde or glutaraldehyde. Therefore, the quantitative assay is highly sensitive and reproducible since the structure of sperm surface antigens is not altered by the fixation process.

CONCLUSIONS

The prevalence of ASAs in this population was 14%, while the prevalence of the control group was 2.5%. Of all factors analyzed only a history of vasectomy, an acute epididymitis, and an abnormal result in the bovine mucus penetration test was associated with elevated ASA titers (P < .001). In addition, we could demonstrate a time related formation of ASAs in men after vasectomy.

Serum antisperm antibodies in men with vas deferens obstruction caused by childhood inguinal herniorrhaphy

OBJECTIVE

To study the incidence of serum antisperm antibodies in patients with vas deferens obstruction caused by childhood inguinal herniorrhaphy.

DESIGN

Retrospective.

SETTING

Kansai Medical University and Kyoto University Hospital.

PATIENTS

Thirteen patients with vas deferens obstruction caused by childhood inguinal herniorrhaphy.

MAIN OUTCOME MEASURES

Indirect immunobead test for serum antisperm antibodies.

RESULTS

Of 13 patients, 7 (54%) and 2 (15%) tested positive for immunoglobulin (Ig)G and IgA class antisperm antibodies, respectively; all patients tested negative for IgM class antibodies. The incidence of antisperm antibodies was not different between the patients with possible epididymal obstruction and those without epididymal obstruction.

CONCLUSIONS

A significant percentage of patients with vasal obstruction caused by infant inguinal herniorrhaphy have serum antisperm antibodies despite the absence of sperm granulomas.

Variation in antisperm antibody response following transection of male genital tract in Lewis rats

Genital tracts of male Lewis rats were transected at various levels to determine whether this may influence antisperm antibody response. Adult male rats underwent bilateral transection of the vas deferens (group I, n = 9), mid-epididymis (group II, n = 10), and efferent duct (group III, n = 9). Group IV (n = 10) underwent a sham operation. Sera were collected by retro-orbital puncture before the operative procedure and monthly for 3 months postprocedure. Sperm-reactive immunoglobulins IgG, IgA, and IgM were measured individually as well as combined in serum by enzyme-linked immunosorbent assay (ELISA) using lithium diiodosalicylate (LIS)-solubilized washed rat caudal epididymal sperm. The maximal immune response was seen in all groups at 2 months postprocedure. Antibody response defined as the net ELISA absorbance reading for the combined immunoglobulin group were (mean +/- SEM): group I = 120 +/- 16, group II = 156 +/- 23, group III = 190 +/- 20, and group IV = 116 +/- 22. The highest antibody response was noted in the efferent duct group, which was statistically (p < .05) greater than the sham-operated and vas deferens groups. In the efferent duct group the highest immunoglobulin response was observed in the IgG class, which was significantly higher (p < .05) than the IgA and IgM classes. The transection of the male genital tract at different levels leads to variation in antisperm antibody response and that sperm located at different sites along the genital tract may differ in their autoantigenic potential.

Effect of early antibiotic treatment on the formation of sperm antibodies in experimentally induced epididymitis

This investigation was conducted to evaluate whether or not experimentally produced epididymitis could induce the development of cytotoxic sperm antibodies and if effective antibiotic therapy could reverse the development of immunity to sperm. Escherichia coli was injected into the tail of the epididymis in adult Lewis rats to induce epididymitis and was allowed to incubate for 24 h, 72 h, 8 days, or 15 days. Serum titers of cytotoxic sperm antibodies at these time intervals were determined. Sperm antibody titers began to rise 3 days after inoculation, peaked, and plateaued at 8 days. The titers were negligible in the control rats. Two other groups of rats were inoculated with E. coli in a similar manner and were treated with tetracycline 25 mg/kg/day starting at either 24 h or 8 days after inoculation, for 7 days. The antibody titers became negligible in these two treated groups, the results being statistically significant when contrasted with the infected but untreated groups (p < .001 and < .05, respectively, for the 24-h and 8-day groups). However, histological examination of the antibiotic-treated and untreated specimens revealed significant inflammation and infection of the epididymis in both treated groups. Testicular alterations were consistent in both groups. It is concluded that epididymitis consequent to infection with E. coli can induce cytotoxic antibody formation in Lewis rats. Treatment with appropriate antibiotics may suppress the antibody response either through a direct immunosuppressive effect of the antibiotic or through a decrease in the antigenic load of killed sperm secondary to eradication of the infection.

Vasectomy and prostate cancer risk: methodological review of the evidence

Two recent studies have reported a significantly elevated risk of prostate cancer among vasectomized men. To assess whether the new results conflict with earlier studies that found no significant overall association, and, if so, whether such a conflict could have a methodological basis, we reviewed the six major epidemiological studies of this topic. Statistical analysis revealed significant (p < 0.01) heterogeneity among the associations in the six studies, attributable to one of the recent studies. Scrutiny of the studies for fulfillment of eight methodological standards for scientific validity revealed that no study completely fulfilled more than four standards, and that all studies were deficient in avoiding detection bias and obtaining accurate vasectomy histories. Our review indicates that the evidence on this topic is indeed conflicting, that the quality of the evidence does not resolve the conflict, and that future studies of this topic, designed to ensure scientific credibility of results, are needed.

Testicular torsion: a follow-up study

Thirty-five patients were examined 6-11 years after operation for torsion of the testis. Loss of testicular tissue was significantly associated with long preoperative duration of symptoms and with low postoperative sperm counts. The sex hormones were normal in the majority of patients but there were significantly higher levels of both FSH and LH in the group of patients with symptoms exceeding 8 hours. There was also a higher prevalence of abnormal semen quality in the same group. Furthermore, FSH and LH levels correlated significantly to the duration of symptoms and correlated inversely to the sperm count and concentration. Measurement of carnitine levels in seminal plasma, as a sign of vas deferens obstruction or dysfunction of epididymis, and of autoantibodies against spermatozoa revealed no significant findings.

Auto-antibodies to human sperm basic nuclear proteins in infertile and vasectomized men: characterization of antigens and epitopes recognized by antibodies

The sera of vasectomized men and of patients with immune infertility were used to study the antigens and epitopes of sperm nuclear proteins that bind antibodies in these sera. No reaction with sperm histones was observed except for one serum. P1, P2 protamines and pro-P2 protamines were recognized by auto-antibodies. Studies with peptides derived from P1 and P2 protamines and with mammalian protamines related to HP1 showed that antibodies are mainly specific for a folded protamine molecule, more especially antibodies from vasectomized men. These results disagree with the random coil model proposed for protamines by several previous works. A cross-reactivity between P1 and P2 protamines was observed only for the whole molecules and not for peptides derived from them. This observation suggests that the two classes of protamines, different in sequence, may have a similar folding and thereby may be functionally equivalent.

Incidence of disease after vasectomy: a record linkage retrospective cohort study

OBJECTIVE

To determine whether vasectomy is associated with an increased risk of several diseases, and in particular testicular cancer, after operation.

DESIGN

Retrospective cohort study using linked medical record abstracts.

SETTING

Six health districts in Oxford region.

SUBJECTS

13,246 men aged 25-49 years who had undergone vasectomy between 1970 and 1986, and 22,196 comparison subjects who had been admitted during the same period for one of three specified elective operations, appendicitis, or injuries.

MAIN OUTCOME MEASURES

Hospital admission and death after vasectomy or comparison event.

RESULTS

The mean durations of follow up were 6.6 years for men with a vasectomy and 7.5 years for men with a comparison condition. The relative risk of cancer of the testis in the vasectomy cohort (4 cases) compared with that in the other cohorts (17 cases) was 0.46 (95% confidence interval 0.1 to 1.4), that of cancer of the prostate (1 v 5 cases) 0.44 (0.1 to 4.0), and that of myocardial infarction (97 v 226 cases) 1.00 (0.8 to 1.3). There was no evidence of an increase associated with vasectomy in the incidence of a range of other diseases.

CONCLUSIONS

Vasectomy was not associated with an increased risk of testicular cancer or the other diseases studied. With respect to prostatic cancer, while we found no cause for concern, longer periods of observation on large numbers of men are required.

Surgical technique for inguinal surgery and its effect on fertility in the Wistar rat model

This study has explored the relatively neglected effects of operative manipulation of the vas deferens on fertility. Following unilateral vasectomy the contralateral vasa of 52 4-week-old Wistar rats were subjected to 7 different manipulations. After 7 weeks a fertility trial was conducted. All sham operated rats (n = 18) were fertile. Of the remaining 34 rats, 22 (65%) were sterile. All of those with tight ring reconstruction (n = 6) were sterile, due initially to venous obstruction. Nine of 14 rats with acute clip trauma (65%) remained fertile but 11 of 14 (78%) with full mobilisation were sterile owing to extensive avascular fibrosis of the vas deferens. These results suggest that overzealous cord handling and operative technique in the immature animal is counterproductive and leads to vasal occlusion. This may have important repercussions in paediatric inguinal surgery, with a subsequent higher incidence of azoospermia and male subfertility.

Localization of post-vasectomy sperm autoantigens in the Lewis rat

Major rat sperm autoantigens of 86, 63, 43, 28 and 20 kDa are recognized by post-vasectomy and hyperimmunization antisera from the Lewis rat (Handley et al., Biol. Reprod. 39 (1988) 1239-1250). In the present study, affinity purified monospecific isoantibodies to each autoantigen were produced by elution from antigens which had been separated by SDS-PAGE and transferred to nitrocellulose. Western blot analysis confirmed a singular specificity for the 63, 28 and 20 kDa antisera and demonstrated some cross reactivity between the 86 kDa and the 43 kDa antisera. The polyclonal antiserum from which the monospecific antisera were produced stained the entire spermatozoon, while monospecific antibodies bound only to the sperm tail, staining the proximal portion (43 and 28 kDa), a distal domain (63 kDa), or the entire tail (86 kDa). Immunohistochemically stained sections of normal rat testes revealed that the 63, 43 and 28 kDa autoantigens were synchronously expressed in the cytoplasm of spermatids in the apical portions of seminiferous tubules during stages II-VIII in the cycle of the seminiferous epithelium. The 86 kDa autoantigen showed little or no staining in testis sections, implying that this autoantigen appeared on mature sperm following spermiation. These and other data suggest that a highly polymeric structure, possibly within the outer dense fibers of the tail, is a dominant sperm autoimmunogen following vasectomy of the Lewis rat.

Does vasectomy have long-term effects on somatic and psychological health status?

All the major international articles on the somatic and psychological consequences of vasectomy published over the last 10 years have been reviewed and analysed. Although some experiments on animals have revealed harmful effects, none of the large-scale epidemiological studies has pointed to any increase in health risks (cardiovascular, hypertensive, psychiatric) in vasectomized men. The contradictions which arise between the clinical and large-scale epidemiological studies may be the result of methodological or experimental conditions. As our knowledge stands at present it can therefore be considered that vasectomy has no major effects on the physical or mental health of men.

Effect of vasectomy on in situ pH in rat testis and epididymis

The effect of bilateral vasectomy on in situ pH in seminiferous tubules, initial segments, proximal caput, middle corpus and proximal cauda epididymides of the rat has been studied employing in vivo microelectrode techniques. After bilateral vasectomy of four weeks duration, a significant increase in acidity of luminal fluid in the initial segments of the caput epididymides was observed. By eight weeks post vasectomy, luminal pH in the initial segments was significantly more acid as compared to sham-operated control animals or four weeks vasectomy while, in contrast, luminal pH in the proximal cauda epididymides was significantly more alkaline. The alteration of luminal fluid pH in the initial segments and proximal cauda epididymides after bilateral vasectomy may be the result of impairment of acid-base, as well as water transport pathways.

Immunological status of patients before and after vasovasostomy as determined by the immunobead antisperm antibody test

With the immunobead antisperm antibody test a prospective study was conducted to evaluate the immune status of 55 men before and after vasectomy reversal. A third of the vasectomy patients (19 of 55) had significant serum-sperm antibodies (20 per cent binding or more) detected by the indirect immunobead antisperm antibody test. Of 31 vasovasostomy patients 12 (38 per cent) had significant sperm-surface antibodies (20 per cent binding or more) by the direct immunobead antisperm antibody test. Preoperative serum assays correctly classified the antibody status of 69 per cent of the vasectomy patients. The immunological impact of spermatic granuloma formation, duration of vasal obstruction, patient age and presence of sperm in the vasal fluid at operation also were assessed. An inverse relationship between the proportion of antibody-bound sperm and the percentage of motile sperm in the ejaculate of vas reversal patients was found with videomicrographic semen analysis. The percentage motility was significantly lower among patients with greater quantities of sperm-surface antibodies. No other parameter of semen analysis showed this difference when compared for positive or negative immunobead antisperm antibody test results.

Detection of testicular endocrine abnormalities and their correlation with serum antisperm antibodies in men following vasectomy

We measured the serum gonadotropin response to gonadotropin-releasing hormone in 25 men who underwent vasectomy 2 to 64 months before the study. Ten age-matched fertile men were used as controls. Baseline serum follicle-stimulating hormone, luteinizing hormone and testosterone levels were not significantly different between vasectomized men and controls. However, mean serum follicle-stimulating and luteinizing hormone responses to an intravenous bolus injection of 100 mcg. gonadotropin-releasing hormone were significantly greater in the vasectomy group (p equals 0.008 and 0.003, respectively). There was no correlation between these responses and the interval after vasectomy. Serum antisperm antibodies were present in 13 vasectomized men (52 per cent) using enzyme-linked immunosorbent assay and microagglutination techniques. A significant correlation (p equals 0.003) was found between the presence of serum antisperm antibodies and a normal follicle-stimulating hormone response to gonadotropin-releasing hormone stimulation. Of 13 patients with demonstrable antisperm antibody titers 9 (69 per cent) had normal follicle-stimulating hormone responses, compared to only 1 of 12 (8 per cent) without identifiable antisperm antibody titers. Our data suggest that certain men following vasectomy have abnormalities in seminiferous tubule and Leydig cell functions of the testes. These abnormalities are unrelated to the interval after vasectomy and are not identifiable with routine static hormonal measurements. In addition, serum antisperm antibodies are most likely to be present in men who demonstrate normal seminiferous tubular activity after vasectomy.

Male or female sterilization: a comparative study

The study compares 709 males and 546 females recruited from a well-defined geographic area and sterilized during a 5-year period at the same hospital. Medical records were reviewed and questionnaires sent out. Widespread satisfaction with the sterilization was found. The sterilized women had experienced contraceptive side effects and failures more often than the men. Only 70% of the laparoscopic sterilizations could be carried out during a 1-day admission, 25% of the women complained about long-term sequelae, and there were 1% failures. The vasectomies were carried out on an outpatient basis, there were few postoperative symptoms, and 0.5% failures were recorded. Female sterilization was at least four times as expensive as vasectomy. It is concluded that vasectomy is generally to be preferred to female sterilization, and that the preoperative guidance should involve both man and wife.

Testicular alterations are linked to the presence of elevated antisperm antibodies in Sprague-Dawley rats after vasectomy and vasovasostomy

The relationship between alterations in testicular histology and antisperm antibodies was studied after vasectomy and vasovasostomy in Sprague-Dawley rats, which are immunologically relatively non-responsive to vasectomy. Testes were prepared for histologic study at intervals up to seven months after vasectomy, vasectomy followed three months later by vasovasostomy, or sham operations. Antisperm antibodies were assessed with an ELISA. Testicular alterations, which were observed in a minority of animals after vasovasostomy, consisted mainly of depletion of germ cells. Mean serum antisperm antibody levels were greater for animals with altered testes than for rats with normal testicular histology. In addition, the proportion of rats that showed a positive antisperm antibody response was greater among animals with testicular changes than among those with unaltered testes. When the present results on Sprague-Dawley rats were compared with previous findings on the highly responsive Lewis strain, it was evident that the incidence of testicular changes and the proportion of positive antibody responders were greater in the Lewis strain. However, elevated antisperm antibodies and testicular alterations appeared to be more tightly linked in the less responsive Sprague-Dawley rats.

IgG antisperm antibodies attached to sperm do not correlate with infertility following vasovasostomy

The sperm of 12 men postvasovasostomy was tested for antisperm antibodies by means of a mixed antiglobulin reaction (MAR) test. Agglutinating antibodies were found in 58% of these patients: 50% of the men whose partners became pregnant and 75% of those whose partners did not become pregnant. No significant difference in the level of antibody attachment could be found between the fertile group and the infertile group. Damage to the testis and epididymis following vasectomy seems more likely to interfere with subsequent fertility following vasectomy reversal.