Predictive value of in-vitro sperm function tests in the context of an AID service

Our inability to predict the fertilizing potential of an ejaculate in vivo is central to the dilemmas which confront clinical andrologists. In this paper, we examine the ability of laboratory tests of sperm function to predict the fertilizing ability of an ejaculate in vivo, in the context of a retrospective analysis of cryostored semen used in an AID programme. Samples were subjected to a conventional semen analysis, measurement of ATP levels, zona-free hamster oocyte penetration testing and examination of sperm movement characteristics by time-exposure photography. Using a multivariate discriminant analysis, we were able to distinguish successful from unsuccessful ejaculates with an overall accuracy of 81.25% (P = 0.0191) based upon data derived from the conventional semen profile, hamster oocyte penetration and the assessment of sperm movement.

Paradoxical stimulation of human sperm motility by 2-deoxyadenosine

Exposure of cryostored human spermatozoa to 2-deoxyadenosine resulted in significant increases in percentage motility, the linear velocity of progression and the frequency of sperm head rotation, which were maximal at a dose of 2.5 mM. At the same dose both adenosine and caffeine significantly increased percentage motility, although neither compound influenced the quality of sperm movement as assessed by time-exposure photomicrography. 2-Deoxyadenosine was also significantly more effective than caffeine in sustaining the motility of cryostored spermatozoa as well as in enhancing the motility of fresh and washed preparations of human spermatozoa. The ability of caffeine and 2-deoxyadenosine to influence sperm motility was counteracted by the presence of calcium in the external medium although the latter was less susceptible to such inhibition and still enhanced motility in the presence of calcium levels (1.7 mM) typical of media used for in-vitro fertilization. The mechanism of action of 2-deoxyadenosine was associated with an increase of intracellular cAMP levels, which were sustained over a time course lasting from 5 to 180 min and exhibited significant dose dependency over the range 1-10 mM. The response to 2-deoxyadenosine did not involve any changes in the steady state levels of ATP and was augmented by the presence of the phosphodiesterase inhibitors, IBMX and caffeine. We conclude that 2-deoxyadenosine is a powerful stimulator of human sperm motility and that this effect involves an increase of intracellular cAMP levels via mechanisms which do not involve the classical 'R'-site receptor mediated pathway.

Application of a Poisson-gamma model to study the influence of gamete concentration on sperm-oocyte fusion in the zona-free hamster egg penetration test

A Poisson-gamma distribution model has been developed for studying sperm-oocyte interaction in the zona-free hamster egg penetration test. With the aid of this model we have analysed the relationship between the penetration results achieved with semen of normal fertile men and the concentration of spermatozoa and oocytes used in the assay. From this analysis we have drawn up reference tables estimating the number of spermatozoa and oocytes which must be present in the assay for the result to represent a significant (P less than 0.05) decline in sperm function relative to the normal fertile population. Since there is, as yet, no fixed protocol for the penetration assay, these tables have been constructed to fit a range of methodologies varying with respect to the nature of the preincubation phase and including (a) a 7-h preincubation in Medium BWW, (b) a 3-h preincubation in hyperosmotic Medium BWW or (c) a 3-h preincubation in the presence of A23187.

Raising a colostomy--results of a prospective surgical audit

A prospective surgical audit of all colostomies fashioned over a 1-year period in one hospital was conducted. Of one hundred and ten colostomies there were 56 loop and 52 end stomas. Following the formation of the colostomy a proforma was completed and the surgeon interviewed to document the precise surgical technique employed. Whilst in hospital the patients were regularly reviewed and the colostomies assessed by a surgeon and stomatherapist using a scoring system. Follow up was continued until closure of the colostomy or for a minimum period of 1 year. Only 53 (48%) of patients saw a stomatherapist preoperatively. This rate was higher in elective (86%) than in urgent cases (15%). The surgial technique used did not appear to influence the outcome of any given colostomy. However, failure to cruciate the posterior rectus sheath may predispose to stomal stenosis and the use of a subcutaneous polyethylene rod to support a loop colostomy often led to infection. Tension of the colostomy led to complications in 29 cases (26%), this was often the precipitating event to other complications and led to the only colostomy-related death. Registrars with experience of fewer than 5 colostomies received their training largely from other registrars rather than consultants. This prospective surgical audit has disclosed that fashioning a colostomy carries significant stoma related morbidity, most of which is potentially avoidable. Appropriate audit can contribute to the maintenance and improvement of surgical standards.

Significance of intracellular calcium and cyclic adenosine 3',5'-monophosphate in the mechanisms by which prostaglandins influence human sperm function

The selective ability of PGE-1 and PGE-2 to enhance the capacity of human spermatozoa for hamster oocyte penetration was dependent upon high concentrations (1.7 mM) of extracellular Ca2+ and a prolonged (4 h) duration of exposure, and insensitive to the Ca2+ channel antagonist, verapamil. Studies with the intracellular calcium indicator Quin-2 indicated that exposure to PGE-1 and PGE-2, but not PGF-2 alpha, induced a significant rise in the levels of cytoplasmic Ca2+, suggesting that an ionophore-like action might be responsible for the ability of the E-series prostaglandins to influence sperm function. Stimulation of oocyte penetration with PGE-1 and PGE-2 was significantly enhanced when these compounds were presented to the spermatozoa in medium of high osmolarity (410 mosmol). A combination of PGE-1 in hyperosmotic medium did not significantly influence sperm function in cases of oligozoospermia, although it was effective with patients exhibiting idiopathic infertility. Exposure to high doses of PGE-1 and PGE-2, but not 19-hydroxy PGE or PGF-2 alpha, also induced a significant rise in the cyclic AMP content of human spermatozoa. This effect did not appear to be involved in the enhancement of fertilization rates because it did not exhibit the same absolute dependence on high levels of extracellular Ca2+ as did the fertilization responses and the enhancement of oocyte penetration and the elevation of cAMP were independent of each other within the patient population.

Choledochopancreatoduodenal fistula caused by duodenal ulceration. A case report

A penetrating duodenal ulcer may occasionally erode into the common bile duct and form a choledochoduodenal fistula. Such a fistula occurring simultaneously with a pancreatic duodenal fistula is reported. The presenting features of these fistulas are those of the ulcer and confirmation of the fistula may be difficult, although use of endoscopic retrograde cholangiopancreatography has greatly facilitated their diagnosis. In this case both fistulas could be cannulated through the base of the ulcer. The majority of these fistulas heal spontaneously with intensive medical management. The remainder require surgery, and a conservative approach avoiding direct interference with the fistula should be adopted. Drainage procedures are rarely required and once closed the fistulas usually cause no further problem.

Application of Poisson distribution theory to the zona-free hamster oocyte penetration test to assess sperm function of men with asthenozoospermia

Assessments of the penetrating potential of human spermatozoa were carried out using the zona-free hamster oocyte penetration test on 4 groups of subjects exhibiting normal fertility, idiopathic asthenozoospermia(less than 40% motility), asthenozoospermia associated with varicocele and oligoaesthenozoospermia (less than 20 X 10(6) spermatozoa/ml and less than 40% motility). When the Poisson model was used to correct the results of the in-vitro penetration experiments for differences in motile sperm concentration, significant differences were apparent between the normal fertile controls and all 3 categories of asthenozoospermic patient. Furthermore, the penetrating ability of the motile spermatozoa from patients presenting with a varicocele or oligoaesthenozoospermia was significantly less than that for the group in which asthenozoospermia was the only detectable defect. These results emphasize the practical significance of the Poisson model in the analysis of male fertility and demonstrate that the asthenozoospermic condition is associated with a significant reduction in the fertilizing potential of the motile spermatozoa.

Chromosome studies in human in vitro fertilization

The chromosome constitution of 22 human preimplantation embryos from donor oocytes fertilized in vitro by donor sperm was studied to assess the contribution of lethal chromosome anomalies to the high failure rate of implantation of in vitro fertilized embryos after embryo transfer in infertile women. Evidence was found of nondisjunction, resulting in trisomy, monosomy, and nullosomy; structural abnormalities; haploidy; and triploidy. Despite the lethality of their chromosome complements, these embryos could not be distinguished morphologically from those with normal chromosomes.

Twenty year experience with familial polyposis coli in Cape Town

Forty-nine patients undergoing surgery for familial polyposis coli (FPC) over a twenty year period are presented. Forty-three patients underwent total colectomy with ileorectal anastomosis (TC + IRA) and five patients subsequently developed a rectal carcinoma. The incidence of rectal carcinoma following TC + IRA appears to increase with time. There were significant postoperative complications secondary to adhesive obstruction and desmoid tumour recurrence. Upper gastrointestinal pathology has been detected by endoscopy in only one of nine patients, but the importance of upper gastrointestinal pathology is now appreciated. The problem of screening a widely distributed and closely knit community has been considerable. TC + IRA remains the operation of choice for the majority of patients with FPC, but a total colectomy with ileal reservoir and ileo-anal anastomosis is appropriate in some cases.

Oocyte recovery and fertilization rates in women at various times after the administration of hCG

Volunteer women requesting laparoscopic sterilization were subjected to a fixed schedule of ovulation induction and oocyte recovery. Follicle aspiration was carried out in four groups: those to whom hCG was not administered and 12, 24 or 36 h respectively after the administration of hCG. For each group oocytes were cultured in vitro for 42 h, 30 h, 18 h and 6 h respectively, before insemination with donor spermatozoa. Oocyte recovery rates improved with longer hCG-to-recovery intervals (36% with no hCG to 81% 36 h after hCG). Although there was a slight reduction in fertilization rates when oocytes were not exposed to hCG in the follicle, normal cleavage was noted in more than 50% of oocytes in all four groups. It therefore appears that the final maturation stages of the human oocyte are not dependent on the midcycle gonadotrophin surge, provided the oocyte is matured in vitro before insemination. However, it was also evident that the fertilization rates were reduced when oocytes were removed from less mature follicles, as reflected by high androstenedione/oestradiol ratios.

Factors influencing the success of sperm-cervical mucus interaction in patients exhibiting unexplained infertility

The factors regulating the success of sperm-cervical mucus interaction in 46 patients exhibiting unexplained infertility were analyzed. Within this group of patients, considerable variation in the degree of mucus penetration, which appeared to be related to the properties exhibited by the spermatozoa rather than the quality of the mucus itself, was observed. The ability of the spermatozoa to fuse with zona-free hamster oocytes reflected their capacity for mucus penetration, regardless of whether human or bovine cervical mucus was used as the target. Multiple regression analysis also indicated the importance of the movement characteristics exhibited by the spermatozoa, which alone could account for up to 85% of the variability in mucus penetration. The concentration of motile spermatozoa and their linear velocity of progression influenced the number of spermatozoa penetrating the mucus in unit time, presumably through an effect on the frequency of collisions at the cervical mucus interface. Whether these collisions resulted in mucus penetration depended upon the movement characteristics of the spermatozoa and was positively associated with a "rolling" mode of progression and the amplitude of lateral sperm head displacement.

The value of adenosine triphosphate (ATP) measurements in assessing the fertilizing ability of human spermatozoa

A study was undertaken to examine the relationship between adenosine triphosphate (ATP) levels and the fertilizing capacity of human spermatozoa in vitro and in vivo. The concentration of ATP in semen was found to be positively correlated with the ability of sperm to fuse with zona-free hamster oocytes. However, it was also demonstrated that a large part of this relationship depends upon the relationship between semen ATP concentrations and sperm number. Measurements of ATP levels in cryostored ejaculates used in an artificial insemination by donor program revealed that such measurements were not able to distinguish fertile from infertile ejaculates. However, among fertile donors, ATP levels did seem to contribute useful information on relative fertility. It is concluded that ATP measurement has a limited role in the laboratory evaluation of sperm function.

Diagnostic value of the zona-free hamster oocyte penetration test and sperm movement characteristics in oligozoospermia

A group of 27 oligozoospermic patients were followed up for 4.2 +/- 1.1 years in a prospective study designed to determine which aspects of semen quality are of value in the diagnosis of fertility. The semen analysis included the zona-free hamster oocyte penetration test, the assessment of sperm movement characteristics by time exposure photomicrography and a conventional semen profile. During the follow up period, 7 patients (25.9%) initiated a pregnancy. The identity of these fertile subjects could not have been ascertained by any single criterion of sperm movement or any feature of the conventional semen profile. The zona-free hamster egg penetration rates were also of little value in this respect since 4 of the 7 fertile patients scored 0% in this assay. Using a multivariate discriminant analysis, however, a combination of 7 criteria was identified, including hamster oocyte penetration and elements of both sperm movement and the semen profile, which could predict the fertility of these patients with 85.2% accuracy.

Sigmoid exclusion: a new technique in the management of radiation-induced fistula

Colovesical and colovaginal fistulas following irradiation for pelvic malignancy represent a formidable surgical problem. Although complex surgical procedures to close the fistulas and restore continence have been described, often a defunctioning colostomy with an associated urinary conduit is the only feasible option. Three patients who have successfully undergone an original procedure (sigmoid exclusion) are presented. Sigmoid exclusion restores continence but avoids a permanent stoma. The involved sigmoid colon was isolated on its mesentery ensuring that the area incorporating the fistulas was not disrupted. The ends of the isolated sigmoid colon were closed and bowel continuity then restored by a colorectal or colo-anal anastomosis. Following closure of a temporary colostomy the patients were continent with no ill effects or sepsis from the excluded colon. This procedure has the dual advantage of restoring continence yet avoiding both an urinary conduit and a permanent colostomy, and represents a useful advance in the surgical management of radiation induced colonic fistulas.

Girth measurement is not a reliable investigation for the detection of intra-abdominal fluid

Routine measurement of abdominal girth after suspected trauma is still recommended as a predictor of intraperitoneal bleeding but there is little evidence to support its accuracy. Girth measurements were taken on 12 recumbent adult patients by independent observers and repeated after infusion of 550 ml aliquots of dialysate to a maximum of 2000 ml. Girth increase per 500 ml infusion varied from -0.46 cm to 2.1 cm (mean 0.84 +/- 0.65 SD) giving a range in excess of 2.5 cm. In some cases the girth decreased after a further 500 ml infusion. A change in patient position altered the girth at a constant volume by 1.32 cm (+/- 0.75 SD). Observer error was low at 0.33 cm (+/- 0.35 SD). These results preclude girth as a reliable clinical indicator of intraperitoneal haemorrhage.

Relationship between the movement characteristics of human spermatozoa and their ability to penetrate cervical mucus and zona-free hamster oocytes

In a group of normospermic donors exhibiting hamster oocyte penetration scores of 0-100%, multiple regression analysis indicated that only 20% of the variation in fertilizing potential could be explained by differences in the movement characteristics of the spermatozoa following incubation in vitro. When the movement characteristics of the spermatozoa in semen were considered this figure was reduced to 6.8% as a result of significant differences in the motility patterns exhibited by the seminal and post-incubation sperm populations. A much closer relationship was observed between the movement characteristics of human spermatozoa in semen and their ability to penetrate cervical mucus. When differences in motile sperm densities were taken into account, 76% of the variation in cervical mucus penetration could be accounted for by the existence of linear correlations with certain aspects of sperm movement (multiple R = 0.874). Of the various attributes of sperm motility measured (linear velocity of progression, frequency of rotation, amplitude of sperm head displacement, % rolling and % yawing), a failure to exhibit an adequate amplitude of lateral sperm head displacement was consistently found to be the most significant factor determining the success of sperm-cervical mucus interaction (R2 = 0.53).

Analysis of the direct effects of prostaglandins on human sperm function

Time-exposure photomicrography and interspecies in-vitro fertilization procedures have been used to examine the influence of prostaglandins on human sperm function. An analysis of variance indicated that the presence of PGs in the incubation media was associated with a significant increase in sperm velocity and the frequency of sperm head rotation, although there were no differences between individual PGs in the degree of stimulation observed. Changes in the penetrating ability of human spermatozoa were detected after exposure to PGs, particularly PGE-1 and PGE-2. PGE-2 induced a sustained increase in penetration rates at all doses of greater than 8.4 micrograms/ml, while exposure to PGE-1 gave a bell-shaped dose-response curve which exhibited a peak between 8.4 and 33.3 micrograms/ml and progressively fell to reach control levels at the maximum concentration tested of 270 micrograms/ml. A combination of PGE-2 and PGE-1 produced a dose-response curve similar to that for PGE-1 alone, while exposure to PGF-2 alpha was without effect. Seminal extracts containing predominantly 19-hydroxy PGE-1, or equal amounts of 19-hydroxy PGE-1 + 2 induced a slight, but significant, rise in penetration rates while a combination of PGs representing the major components of human seminal plasma was without significant effect. We conclude that certain prostaglandins may have a direct action on the functional competence of human spermatozoa.

Significance of Poisson distribution theory in analysing the interaction between human spermatozoa and zona-free hamster oocytes

The value of Poisson distribution theory in describing and predicting the nature of sperm-egg interaction in vitro has been investigated using an interspecific in-vitro fertilization system, incorporating zona-free hamster oocytes and human spermatozoa. The frequency distribution of polyspermic oocyte penetrations in 72 experiments exhibited good agreement with the Poisson distribution at all levels of fertilization indicating that each oocyte must be of equal penetrability and that there can be no block to polyspermy in this interspecific system. Poisson distribution theory also accurately described the relationship between oocyte penetration and sperm motility in 50 out of 54 separate experiments spread across 10 serial dilution curves. For each dilution series the shape of the fitted curve was fixed but its location along the x-axis varied from donor to donor. The fixed nature of the relationship between sperm motility and egg penetration enables the results of such in-vitro fertilization experiments to be corrected for the number of motile spermatozoa in the incubation media. On the basis of these findings a protocol is described for assessing the results of the zona-free hamster oocyte penetration assay, which involves analysis of the degree of polyspermy followed by the application of Poisson distribution theory to correct the results to a standard concentration of motile spermatozoa. Changes in the penetrating ability of human spermatozoa after vasectomy and characterization of the degree of inter-ejaculate variation in penetrating potential are two clinical examples of such analyses given in the text. The statistical methods described in this paper should also be of general relevance to the study of fertilization mechanisms, in providing a rationale by which to analyse the quantitative nature of sperm-egg interaction in vitro.

In vitro fertilization for male infertility

Rising attention has recently focussed on the possibility of using the in vitro fertilization/embryo transfer procedure (IVF) in the treatment of male infertility. In this paper the Authors describe this application of IVF therapy with particular emphasis on the criteria employed for patient selection and pharmacological enhancement of sperm function.