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Biomedical subjects

R J Aitken

Publications and source records attributed to R J Aitken.

At least 163 records · Page 9Linked to original sources
PubMed1987

Relative ability of modified versions of the hamster oocyte penetration test, incorporating hyperosmotic medium or the ionophore A23187, to predict IVF outcome.

This study was designed to assess the relationship between IVF outcome and the results obtained with two modified versions of the zona-free hamster oocyte penetration test in which the spermatozoa were pre-incubated with either hyperosmotic medium or the divalent cation ionophore A23187. When the former system was used, a poor correlation with IVF outcome was observed. Samples screened prior to IVF exhibited a 60% false negative rate (failed penetration test, successful IVF), while for those assessed concurrently with IVF, the equivalent figure was 85.7%. Addition of A23187 optimized the penetration system giving higher levels of sperm--oocyte fusion and a more accurate prediction of the capacity of the spermatozoa to fertilize human ova in vitro. With this system the false negative rate was 4.3% for screened samples and 0% for those assessed simultaneously with IVF. These results suggest that the A23187-enhanced system may be of value as a screening criterion for IVF.

Animals↗
PubMed1987

The postphlebitic syndrome following shaft fractures of the leg. A significant late complication.

Sixty patients each of whom had a fracture of the lower limb a minimum of five years (median 11 years) previously were studied by photoplethysmography, foot volumetry, popliteal venous reflux and arterial Doppler measurements. The non-fractured limb was used as a control. Postphlebitic symptoms were present in 51% and signs in 49% of fractured limbs compared with 4% and 24% respectively in the control limbs. The incidence was greater in patients who had fractured 15 years or more previously than in those who had fractured 5 to 15 years previously. Eleven limbs had clinically disabling postphlebitic symptoms including venous ulceration. The postphlebitic syndrome following lower limb fractures in young patients is more common than generally appreciated and develops after a prolonged latent interval. A prospective randomised study using prophylactic anticoagulation for lower limb shaft fractures may be justified.

Adolescent↗
PubMed1987

Analysis of the surface labelling characteristics of human spermatozoa and the interaction with anti-sperm antibodies.

Washed ejaculated human spermatozoa were surface labelled with 125I, using solid phase (iodogen) or enzymic (lactoperoxidase) methods, while membrane components possessing terminal galactose or galactosamine residues were labelled with the galactose oxidase-sodium [3H]borohydride technique. All three procedures revealed the presence of 2 major labelled surface components. The first comprised a broad band of radioactivity migrating just behind the ion front on SDS-PAGE, which could be extracted with chloroform and methanol, suggesting a lipid-like composition. The second fraction exhibited properties consistent with a major glycoprotein component of the human sperm plasma membrane, giving a peak of radioactivity with Mr = 20,000, within which a discrete doublet of bands (Mr = 17,000 and 19,000) could be resolved by autoradiography. A more detailed analysis of the labelled protein fraction after TCA precipitation revealed a number of other surface components, the major ones of which exhibited Mr values of 30,000, 45,000, 66,000, 115,000 and 160,000. Western blot analysis was then used to determine whether any of the surface components described above interacted with the gamma-globulin fraction of antisera obtained from patients exhibiting idiopathic autoimmunity against sperm antigens. Using a purified membrane preparation as the target, antibodies were detected against numerous high molecular weight bands with Mr values similar to the major components of the human sperm surface (35,000, 45,000, 66,000, 90,000 and 150,000). The nature of the antigens targeted by these antisera did not correlate with the ability of the latter to stimulate or suppress sperm-oocyte fusion.

Autoantibodies↗
PubMed1987

Cellular basis of defective sperm function and its association with the genesis of reactive oxygen species by human spermatozoa.

Addition of the divalent cation ionophore, A23187, to washed populations of human spermatozoa resulted in a sudden burst of production of reactive oxygen species which peaked within 3-5 min. This activity was dependent upon the presence of calcium in the external medium and was unaffected by the mitochondrial inhibitors, oligomycin, antimycin and rotenone. Studies with scavengers of reactive oxygen species revealed that, while reagents directed against singlet oxygen and the hydroxyl radical were without effect, cytochrome C reduced the response to A23187 by about 50%, suggesting that the superoxide anion radical is a major product of the activated human spermatozoon. The clinical implications of these studies stem from the considerable variation observed between individuals in the levels of reactive oxygen species produced by the spermatozoa. This variability was shown to be inversely related to the ability of the spermatozoa to exhibit sperm-oocyte fusion on exposure to A23187; defective samples exhibited a basal level of reactive oxygen species production which was 40 times that observed with normal functional cells.

Calcimycin↗
PubMed1986

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.

Biliary Fistula↗
PubMed1986

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.

Adolescent↗
PubMed1986

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.

Abortion, Spontaneous↗
PubMed1986

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.

Colostomy↗
PubMed1986

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.

Adenosine Triphosphate↗
PubMed1986

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.

Androstenedione↗
PubMed1986

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.

Animals↗
PubMed1986

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.

Alprostadil↗