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Biomedical subjects

M Vercruyssen

Publications and source records attributed to M Vercruyssen.

14 recordsLinked to original sources
PubMed1993

Subzonal insemination: a prospective randomized study in patients with abnormal sperm morphology.

OBJECTIVE: To evaluate in a prospective randomized study the outcome of subzonal insemination (SUZI) in patients with male subfertility. DESIGN: In a period of 7 months, 48 patients underwent IVF treatment for male subfertility reasons. Normal insemination and SUZI were performed on sibling oocytes. Patients were divided into three groups depending on the sperm morphology (strict criteria): group 1, 10% to 14%; group 2, 5% to 10%; group 3, 0% to 5%. SETTING: Private fertility center in Leuven, Belgium. MAIN OUTCOME MEASURES: The fertilization rates, cleavage rates, implantation rates, and pregnancy rates between the normally inseminated and the SUZI-treated group were compared. RESULTS: The fertilization rate with SUZI was significantly higher (32%) than after normal insemination (7%). The difference was striking in groups 2 and 3 (35% and 33% versus 11% and 4%). CONCLUSION: This study indicates that SUZI increases the fertility outcome in patients with male subfertility and that there is a marked difference in fertilization rate when morphology, using strict criteria, is < 10%.

Female↗
PubMed1993

Mitochondrial distribution after fast embryo freezing.

Mitochondrial distribution pattern after ultrarapid freezing in dimethylsulphoxide was assessed in human multipronucleate zygotes, 2-cell and 4-cell stage embryos using rhodamine 123. The mitochondrial distribution pattern was evaluated at 37 degrees C after a 30 min incubation in rhodamine 123 solution, 4 h and 24 h after thawing. Non-frozen human unfertilized oocytes, 2-cell and 4-cell embryos used as a control showed a homogeneous distribution of mitochondria throughout the cytoplasm, while there was sequestration of mitochondria from the cortex to the region surrounding the pronuclei in multipronucleate zygotes. Morphologically intact multipronucleate zygotes, 2-cell and 4-cell stage embryos after quick freeze-thawing showed the same mitochondrial distribution pattern found in the unfrozen controls. Mitochondria exhibited a typical severe aggregation (clumping) throughout the cytoplasm when non-viable single blastomeres or embryos at thawing were exposed to rhodamine 123. Our study indicates that quick freezing does not affect subcellular structures. The well-organized and specific mitochondrial distribution appeared still to be present after frozen storage, and subcellular structures seemed to be rather resistant targets for cryo-injury.

Cleavage Stage, Ovum↗
PubMed1991

Effects of thermal environment and chemical protective clothing on work tolerance, physiological responses, and subjective ratings.

This study examined the physiological and subjective responses of nine healthy men who performed work while wearing two types of protective ensembles in each of three thermal environments. The subjects, all experienced with the use of protective ensembles, each performed low intensity treadmill exercise (23% of VO2 max while not wearing a Self-Contained Breathing Apparatus [SCBA] or protective clothing) under six experimental conditions: two ensembles (SCBA--light work clothing and SCBA; and CHEM--a two-piece chemical protective ensemble with SCBA) during exposure to 'cool' (10.6 degrees C/water vapour pressure [Pw] 0.76 kPa), 'neutral' (22.6 degrees C/Pw 1.52 kPa), and 'hot' (34 degrees C/Pw 2.90 kPa) environments. Each test was intended to continue for 120 min; however the duration and number of work/rest periods within the testing session varied according to the specific responses of each individual. At the completion of each test seven subjective responses were recorded. Physiological data, collected every minute during each test, included heart rate, and skin and rectal temperature. The total worktime was significantly shorter in the hot environment while wearing the CHEM ensemble (53.4 min) compared to all the other conditions (103-105 min). The mean maximum physiological values also indicated significant differences due to thermal environment and/or ensemble. Work performance did not appear to be limited in a cold environment with either ensemble tested. The physiological responses to working in the CHEM/neutral condition were very similar to those occurring in a hot environment wearing the SCBA ensemble. The subjective responses also indicated significant differences due to thermal environment and ensemble, with subjects perceiving the CHEM ensemble as less favourable than the SCBA ensemble. The results suggested that, even at a low work intensity, individuals wearing chemical protective clothing in the heat will require progressively shorter work periods, and more frequent and longer rest periods.

Adult↗
PubMed1991

Characterization of a de novo duplication of 11p14----p13, using fluorescent in situ hybridization and southern hybridization.

A de novo 11p+ chromosome was found in a child with mild mental retardation but no other remarkable dysmorphic characteristics. Banding studies suggested a duplication of regions 11p13 and 11p14 or regions 11p14 and 11p15. Using fluorescent in situ hybridization and digital imaging microscopy, we mapped probe p32.1 (D11S16) to the proximal part of region 11p14 (11p14.1) and demonstrated duplication of this probe in our patient. Southern hybridization showed duplication of p32.1 and other probes located at 11p13 and 11p14, but the gene for alpha calcitonin (CALCA), located at 11p15, was not duplicated. The application of these techniques led to the identification of the duplication as dir dup(11)(pter----p13::p15.1----qter).

Blotting, Southern↗
PubMed1990

Identification and characterization of normal length nonfluorescent Y chromosomes: cytogenetic analysis, southern hybridization and non-isotopic in situ hybridization.

In two female patients with a 45,X/46,X, +mar karyotype the marker chromosomes were identified as normal length nonfluorescent Y chromosomes (nlYnf) using non-isotopic in situ hybridization (NISH) complementary to routine cytogenetic analysis and Southern hybridization. The recognition of the nlYnf as isodicentric in both patients illustrates and confirms the usefulness and importance of NISH in the identification and characterization of this and many other types of complex chromosome rearrangements.

Adolescent↗
PubMed1989

Work tolerance and subjective responses to wearing protective clothing and respirators during physical work.

This study examined work tolerance and subjective responses while performing two levels of work and wearing four types of protective ensembles. Nine males (mean age = 24.8 years, weight = 75.3 kg, VO2 max = 44.6 ml/kg min) each performed a series of eight experimental tests in random order, each lasting up to 180 min in duration. Work was performed on a motor-driven treadmill at a set walking speed and elevation which produced work intensities of either 30% or 60% of each subject's maximum aerobic capacity. Work/rest intervals were established based on anticipated SCBA refill requirements. Environmental temperature averaged 22.6 degrees C and average relative humidity was 55%. The four protective ensembles were: a control ensemble consisting of light work clothing (CONTROL); light work clothing with an open circuit self-contained breathing apparatus (SCBA); firefighter's turnout gear with SCBA (FF); and chemical protective clothing with SCBA (CHEM). Test duration (tolerance time) was determined by physiological responses reaching a predetermined indicator of high stress or by a 180-min limit. Physiological and subjective measurements obtained every 2.5 min included: heart rate, skin temperature, rectal temperature, and subjective ratings of perceived exertion, thermal sensation, and perspiration. The mean tolerance times were 155, 130, 26, and 73 min, respectively, for the CONTROL, SCBA, FF, and CHEM conditions during low intensity work; and 91, 23, 4, and 13 min, respectively, during high intensity work. Differences between ensemble and work intensity were significant. FF and CHEM heart rate responses did not reach a steady state, and rose rapidly compared to CONTROL and SCBA values. SCBA heart rates remained approximately 15 beats higher than the CONTROL ensemble during the tests. At the low work intensity, mean skin temperatures at the end of the test were 32.7, 33.1, 36.7, and 36.3 degrees C, while mean core temperatures were 37.6, 37.9, 37.9, and 38.5 degrees C, respectively. The subjective data indicated that, in general, subjects were able to perceive relative degrees of physiologic strain under laboratory conditions. Wearing protective clothing and respirators results in significant and potentially dangerous thermoregulatory and cardiovascular stress to the wearer even at low work intensities in a neutral environment. Physiologically and subjectively, firefighter's turnout gear (the heaviest ensemble) produced the most stress, followed by the CHEM, SCBA, and CONTROL protective ensembles.

Body Temperature↗
PubMed1989

Time estimation performance before, during, and following physical activity.

An experiment is reported which evaluated performance on a 10-sec unfilled time interval estimation task before, during, and after physical work on a cycle ergometer at relative intensities of 30 and 60% VO2max. Results from eleven healthy male subjects revealed a significant increase in time estimation variability and a decrease in the mean estimated time intervals during exercise compared to non-exercise phases. These findings are part of a growing body of evidence which indicates that exercise and its severity has a substantive impact on perceptual and cognitive performance, particularly the ability to synchronize and anticipate the timing of events.

Adult↗
PubMed1988

Intraseason changes in the body composition of collegiate female gymnasts.

Body composition measures were collected pre-, mid- and post-season on a team of eight national-calibre collegiate women gymnasts to examine intraseason changes. Also analysed were interseason changes using pre- and post-season data on five of the eight subjects during the current and previous year, according to a 2 x 2 (years x tests) analysis of variance repeated-measures design. Skinfold, circumference and diameter measures were collected with percentage body fat, lean body mass and body density determined by regression equations developed specifically for collegiate female gymnasts. Intraseason body weight decreased significantly from pre- to mid-season (means = 55.0 and 53.6 kg respectively); but the difference between mid- and post-season (53.9 kg) values was not significant (P greater than 0.05). The majority of the 1.4 kg weight loss occurred during intense pre-season conditioning and not during the actual season. Percentage body fat, on the other hand, decreased significantly from pre- to mid-season and mid- to post-season (means = 21.4%, 17.4% and 13.45% respectively; P less than 0.0005). Body density increased significantly from pre- to mid-season and mid- to post-season (means = 1.0476, 1.0584 and 1.0681 respectively; P greater than 0.0005). Of the circumference and skinfold values used in calculating percentage body fat and body density, only the skinfold values displayed significant decreases throughout the season. Interseason analyses revealed no significant changes in any of the dependent measures between seasons, despite consistent trends. There were no significant years x tests interactions and all intraseason changes for two seasons (n = 5) were the same as those found in more detailed analysis of a single season (n = 8) except in the case of weight loss, which was marginally significant (P less than 0.046) in the single-season and not in the dual-season analysis (P greater than 0.05). Body composition of these gymnasts changed in many ways within competitive seasons. The most pronounced changes observed were decreases in subcutaneous fat and increases in body density. This study reinforces the need for administrators, coaches and athletes to be concerned with percentage body fat and skinfold measures rather than weight alone when determining if a person is 'fat'.

Adipose Tissue↗
PubMed1985

Hot air breathing: effects of elevated wet bulb temperatures on tissue temperatures of the mouth.

Six healthy young men breathed room air or one of nine hot humid air conditions on separate days for one hour while walking on a treadmill (40% VO2 max). Inspired wet bulb temperatures ranged from 18.9 (room air) to 49.3 degrees C. Tissue temperatures in the mouth were measured by means of thermocouples placed on the tongue and hard palate. Analysis of variance on repeated measures showed significant increases in both tongue and hard palate tissue temperatures (p less than 0.001) as a result of increasing wet bulb temperatures; however, core temperature and heart rate were not affected (p greater than 0.05). Ratings of subjective discomfort increased proportionally with increases in wet bulb temperature of the inspired air. It was concluded that wet bulb temperature of inspired air is a valuable measure to uses in studying temperature responses of mouth tissues when inhaling hot humid air, particularly when investigating human tolerance levels in order to recommend federal standards for the design of breathing apparatus.

Adult↗