Neil McClure

Objective Psychomotor Skills Assessment of Experienced, Junior, and Novice Laparoscopists with Virtual Reality

Objective assessment of psychomotor skills in surgery is now a priority; however, this assessment is difficult to achieve because of measurement difficulties associated with the reliability and validity of assessing surgical skills in vivo and in the laboratory. In this study virtual reality (VR) was used to overcome these problems in the objective psychomotor assessment of senior, junior, and novice laparoscopists. Twelve experienced laparoscopic surgeons (performed >50 Minimal Access Surgery (MAS) procedures), 12 inexperienced laparoscopic surgeons (<10 MAS procedures), and 12 laparoscopic novices (no MAS procedures) participated in the study. Each subject completed all six tasks of the Minimally Invasive Surgical Trainer; Virtual Reality (MIST VR). In comparison to the other groups, experienced laparoscopic surgeons performed the tasks significantly (p < 0.01) faster, had a lower error rate, were more economic in their movement of surgical instruments and in the use of diathermy. As a group they also showed greater consistency in their performance. MIST VR distinguished between the three groups of laparoscopists. VR provides a useful objective assessment tool for evaluating psychomotor skills for laparoscopic surgery.

Cryopreservation of human semen and prepared sperm: effects on motility parameters and DNA integrity

OBJECTIVE To investigate effects of cryopreservation on sperm motility and DNA integrity. DESIGN Pre-cryopreservation and post-cryopreservation analysis of motility and DNA integrity of semen and prepared sperm samples. SETTING A hospital andrology laboratory. PATIENT(S) Forty men attending the Regional Fertility Centre, Belfast, Northern Ireland. INTERVENTION(S) Each sample was divided, and an aliquot was frozen unprepared. Remaining aliquots were prepared by Percoll density centrifugation (95.0:47.5) or direct swim-up procedure and divided into aliquots to allow direct comparison of fresh and frozen semen and prepared sperm (frozen with or without the addition of seminal plasma) from the same ejaculate. Samples were frozen by static-phase vapor cooling and being plunged into liquid nitrogen. Thawing was carried out at room temperature. MAIN OUTCOME MEASURE(S) Sperm DNA integrity was determined using a modified alkaline single cell gel electrophoresis (comet) assay, and motility was determined using computer-assisted semen analysis. RESULT(S) Sperm frozen unprepared in seminal fluid appeared more resistant to freezing damage than frozen prepared sperm. Further improvements can be achieved by selecting out the subpopulation of sperm with best motility and DNA integrity and freezing these sperm in seminal plasma, making this the optimal procedure. CONCLUSION(S) Freezing sperm in seminal plasma improves postthaw motility and DNA integrity.

Antioxidant supplementation in vitro does not improve human sperm motility

OBJECTIVE To determine the effects of supplementation of preparation media with ascorbate and alpha-tocopherol on subsequent sperm motility and reactive oxygen species production. DESIGN Prospective study to analyze postpreparation human sperm motility parameters and reactive oxygen species production following antioxidant supplementation. SETTING Andrology Laboratory, Royal Maternity Hospital, Belfast, Northern Ireland. PATIENT(S) Sixty patients attending the Andrology Laboratory for semen analysis. INTERVENTION(S) Normozoospermic and asthenozoospermic semen samples (n = 10 for each control and antioxidant group) were prepared by Percoll density centrifugation (95%-47.5%) in media supplemented with ascorbate or alpha-tocopherol to different concentrations within physiologic levels. Controls were included that were not exposed to antioxidant. MAIN OUTCOME MEASURE(S) Sperm motility parameters were assessed using computer-assisted semen analysis. The generation of reactive oxygen species was determined using luminol-dependent chemiluminescence. RESULT(S) The production of reactive oxygen species by sperm was reduced by supplementation in vitro with ascorbate and alpha-tocopherol. However, progressive motility, average path velocity, curvilinear velocity, straight-line velocity, and linearity were decreased significantly, with the greatest inhibition observed with the highest concentrations of antioxidants. CONCLUSION(S) Supplementation of preparation media with ascorbate and alpha-tocopherol, either singly or in combination, is not beneficial to sperm motility.

Virtual reality training leads to faster adaptation to the novel psychomotor restrictions encountered by laparoscopic surgeons

Abstract Background: The fulcrum effect of the body wall on instrument handling poses a major obstacle to the mastery of instrument coordination for junior laparoscopic surgeons. This study evaluated three types of laparoscopic simulator training to assess their ability to promote the users adaptation to the fulcrum effect. Methods: Thirty-two participants with no previous experience in laparoscopic surgery were randomly assigned to one of four groups representing different training conditions. One group was assigned to use a virtual reality simulator (MIST VR); two others were given a laparoscopic Z or U maze-tracking task. The control group received no training. Subjects were asked to perform a 2-min laparoscopic cutting task under normal laparoscopic imaging conditions first before and then after training. Results: In the test trial, subjects who trained on MIST VR made significantly more correct incisions (p <0.0001) and fewer incorrect incisions (p <0.0001). Conclusion: Training on a virtual reality simulator such as MIST VR helps laparoscopic novices adapt to the fulcrum effect faster.

Serum Levels of Vascular Endothelial Growth Factor in Preeclamptic and Normotensive Pregnancy

The purpose of these studies was first to determine if vascular endothelial growth factor (VEGF), a vascular permeability agent, is increased in the serum of women with preclinical and clinical preclampsia (PE), and second to determine how these levels change after delivery. Twenty preeclamptic and 25 normotensive women at term consented to have blood taken pre- and post-delivery. Ten preeclamptic, 10 gestational hypertensive, and 28 normotensive women had blood collected respectively at 12, 20, and 30 weeks gestation and predelivery. Serum was extracted from all samples, and VEGF concentrations were determined by radioimmunoassay. Predelivery, the median serum VEGF concentration in the preeclamptic group was 51.7 ng/mL, and in the control group the concentration was 13.9 ng/mL (P <0.0001). Serum VEGF concentrations fell within 24 hours of delivery in both groups, which resulted in median values of 3.8 ng/mL and 3.2 ng/mL respectively (P <0.3). At 12 and 20 weeks, there was no significant difference between the serum VEGF concentrations in the 3 groups (P <0.3, 0.052 respectively). At 30 weeks, prior to the onset of clinical PE, the serum VEGF levels in the eventual preeclamptic group were elevated significantly compared with the gestational hypertensive and normotensive groups (P <0.001). Predelivery serum VEGF concentrations were significantly elevated in the preeclamptic group and were similar to those in the first study (P <0.0001). These findings suggest that VEGF may be important in the pathophysiology of PE and has the potential to act as a preclinical marker for the condition.

Increased concentrations of the oxidative DNA adduct 7, 8-dihydro-8-oxo-2-deoxyguanosine in the germ-line of men with type 1 diabetes

The effects of diabetes mellitus on male reproductive health have not been clearly defined. A previous publication from this group reported significantly higher levels of nuclear DNA fragmentation and mitochondrial DNA deletions in spermatozoa from men with type 1 diabetes. This study compared semen profiles, sperm DNA fragmentation and levels of oxidative DNA modification in spermatozoa of diabetic and non-diabetic men. Semen samples from 12 non-diabetic, fertile men and 11 type 1 diabetics were obtained and subjected to conventional light microscopic semen analysis. Nuclear DNA fragmentation was assessed using an alkaline Comet assay and concentrations of 7,8-dihydro-8-oxo-2-deoxyguanosine (8-OHdG), an oxidative adduct of the purine guanosine, were assessed by high-performance liquid chromatography. Conventional semen profiles were similar in both groups, whilst spermatozoa from type 1 diabetics showed significantly higher levels of DNA fragmentation (44% versus 27%; P < 0.05) and concentrations of 8-OHdG (3.6 versus 2.0 molecules of 8-OHdG per 10(5) molecules of deoxyguanosine; P < 0.05). Furthermore, a positive correlation was observed between DNA fragmentation and concentrations of 8-OHdG per 10(5) molecules of deoxyguanosine (rs = 0.7, P < 0.05). The genomic damage evident in spermatozoa of type 1 diabetics may have important implications for their fertility and the outcome of pregnancies fathered by these individuals.

Advanced glycation end products accumulate in the reproductive tract of men with diabetes

Light microscopic studies comparing sperm parameters show little association between diabetes and male fertility. However, with the introduction of new analytical techniques, evidence is now emerging of previously undetectable effects of diabetes on sperm function. Specifically, a recent study has found a significantly higher sperm nuclear DNA fragmentation in diabetic men. As advanced glycation end products (AGEs) are important instigators of oxidative stress and cell dysfunction in numerous diabetic complications, we hypothesized that these compounds could also be present in the male reproductive tract. The presence and localization of the most prominent AGE, carboxymethyl-lysine (CML), in the human testis, epididymis and sperm was determined by immunohistochemistry. Parallel ELISA and Western blot analyses were performed to ascertain the amount of CML in seminal plasma and sperm from 13 diabetic and nine non-diabetic subjects. CML immunoreactivity was found throughout the seminiferous epithelium, the nuclei of spermatogonia and spermatocytes, in the basal and principle cells cytoplasm and nuclei of the caput epididymis and on most sperm tails, mid pieces and all cytoplasmic droplets. The acrosomal cap, especially the equatorial band, was prominently stained in diabetic samples only. The amount of CML was significantly higher (p = 0.004) in sperm from non-diabetic men. Considering the known detrimental actions of AGEs in other organs, the presence, location and quantity of CML, particularly the increased expression found in diabetic men, suggest that these compounds may play a hitherto unrecognized role in male infertility.

Comparison of the effects of two methods of cryopreservation on testicular sperm DNA

OBJECTIVE To assess the effects of two methods of freezing on testicular sperm DNA from subjects with obstructive azoospermia and to compare these with samples of fresh and freeze-thawed testicular sperm from fertile men. DESIGN The Comet assay was used to determine the percentage of undamaged DNA in fresh testicular sperm, testicular sperm freeze-thawed in suspension and in a biopsy sample (men with obstructive azoospermia), and in fresh and freeze-thawed testicular sperm (fertile men). SETTING The Regional Fertility Center, Royal Maternity Hospital, Belfast, Northern Ireland, United Kingdom. PATIENT(S) Twelve males with obstructive azoospermia (normal testicular volume and hormone profiles) and nine fertile control subjects. INTERVENTION(S) Trucut needle testicular biopsy under local anesthetic. MAIN OUTCOME MEASURE(S) Measurement of the percentage of undamaged DNA in fresh and freeze-thawed testicular sperm using the Comet assay. RESULT(S) No significant difference was found between the percentage of undamaged DNA of fresh testicular sperm and of both types of freeze-thawed testicular sperm. There was also no significant difference between the percentage of undamaged DNA in fresh or freeze-thawed testicular sperm from controls. Control ejaculated sperm DNA was significantly more damaged than testicular sperm DNA from control men. CONCLUSION(S) Cryopreservation of testicular sperm does not increase baseline levels of DNA damage.

Differences in mitochondrial and nuclear DNA status of high-density and low-density sperm fractions after density centrifugation preparation

OBJECTIVE To determine the mitochondrial DNA and nuclear DNA fragmentation of sperm populations separated by using discontinuous density gradient. DESIGN Analysis of mitochondrial and nuclear DNA status of sperm from high and low density layers. SETTING Regional fertility center. PATIENT(S) Twenty-eight men who presented for an initial infertility investigation. MAIN OUTCOME MEASURE(S) Semen was prepared by using discontinuous density gradient (90.0%:45.0%) and subjected to a modified long polymerase chain reaction to assess mitochondrial DNA deletions and to a modified single-cell alkaline gel electrophoresis assay to determine nuclear DNA fragmentation. RESULT(S) The high-density fraction displayed significantly more wild-type mitochondrial DNA (75% of samples) than did the low-density fraction (25% of samples). In the high-density fraction, the incidence of single deletions was higher than that of double or multiple deletions, and the deletions were predominantly small. A strong correlation was observed between nuclear DNA fragmentation and the number and size of mitochondrial DNA deletions. CONCLUSION(S) Density centrifugation isolates a population of sperm with high-quality mitochondrial DNA and nuclear DNA.

Dietary oestrogens and male fertility potential.

Reports of increased incidences of male reproductive abnormalities and falling sperm counts have prompted interest into the nature of these threats to global fertility. Xenoestrogens have been flagged as major culprits but to date, little is known about the effects of dietary phytoestrogens on male reproductive health. These non-steroidal oestrogens of plant origin are potent endocrine disruptors that modulate normal physiological functions. Phytoestrogens have become a major component in the typical Western fast food diet over the last few decades. Soy formula milk is another common source of phytoestrogens, now used increasingly as an alternative to breast or cows milk for infants with allergies. This use is of particular concern since the most vulnerable periods for oestrogenic insult are thought to be the pre- and neonatal periods when irreversible damage can be inflicted on the developing germinal epithelium. Studies into the safety of phytoestrogens are urgently needed either to allay fears or increase awareness of the effects of our modern diet on future fertility.