Post-exercise skimmed milk, but not a sucrose beverage decreases energy intake at the next meal compared to a placebo beverage in active males.

This study compared the appetite and energy intake effects of three post-exercise beverages at a subsequent post-exercise meal. On three occasions, ten active males: (mean ± sd) age 21.3 ± 1.2 y, V˙ O2peak 58 ± 5 mL/kg/min) performed 30-min cycling at ∼60% V˙ O2peak and five 4-min intervals at 85% V˙ O2peak. Post-exercise, placebo (PLA: 57 kJ), skimmed milk (MILK: 1002 kJ) or sucrose (CHO: 1000 kJ) beverages (615 mL) were consumed. Sixty min post-beverage, subjects consumed an ad-libitum pasta lunch in a 30 min eating period. Subjective appetite and plasma acylated ghrelin and plasma glucose were determined pre-exercise, post-exercise and pre-meal, with sensory characteristics of beverages rated. Ad-libitum energy intake in MILK (6746 ± 2035) kJ) was lower than CHO (7762 ± 1921) kJ) (P = 0.038; dz = 0.98; large effect) and tended to be lower than PLA (7672 (2005) kJ) (P = 0.078; dz = 0.76; medium effect). Including energy consumed in beverages, energy intake was greater in CHO than PLA (P = 0.010; dz = 1.24; large effect) or MILK (P = 0.026; dz = 0.98; large effect), with PLA and MILK not different (P = 0.960; dz = 0.02; trial effect). Plasma ghrelin, plasma glucose and appetite were not different between trials. MILK was perceived thicker than CHO (P = 0.020; dz = 1.11; large effect) and creamier than PLA (P = 0.026; dz = 1.06; large effect). These results suggest that when energy balance is important for an exerciser, post-exercise skimmed milk ingestion reduces energy intake compared to a sucrose beverage and might therefore help facilitate recovery/adaptation without affecting energy balance.

Longitudinal development of match-running performance in elite male youth soccer players.

This study longitudinally examined age-related changes in the match-running performance of retained and released elite youth soccer players aged 8-18 years. The effect of playing position on age-related changes was also considered. Across three seasons, 263 elite youth soccer players were assessed in 1-29 competitive matches (988 player-matches). For each player-match, total distance and distances covered at age group-specific speed zones (low-speed, high-speed, sprinting) were calculated using 1 Hz or 5 Hz GPS. Mixed modeling predicted that match-running performance developed nonlinearly, with age-related changes best described with quadratic age terms. Modeling predicted that playing position significantly modified age-related changes (P < 0.05) and retained players covered significantly more low-speed distance compared with released players (P < 0.05), by 75 ± 71 m/h (mean ± 95% CI; effect size ± 95% CI: 0.35 ± 0.34). Model intercepts randomly varied, indicating differences between players in match-running performance unexplained by age, playing position or status. These findings may assist experts in developing training programs specific to the match play demands of players of different ages and playing positions. Although retained players covered more low-speed distance than released players, further study of the actions comprising low-speed distance during match play is warranted to better understand factors differentiating retained and released players.

Half-time and high-speed running in the second half of soccer.

This study investigated if the quantity of high-speed running (movements >15 km.h(-1) completed in the first 15 min of competitive football matches differed from that completed in the corresponding 15 min of the second half. 20 semi-professional soccer players (age 21.2±3.6 years, body mass 76.4±3.8 kg, height 1.89±0.05 m) participated in the study. 50 competitive soccer matches and 192 data files were analysed (4±2 files per match) using Global Positioning Satellite technology. Data were analysed using 2-way repeated measures ANOVA and Pearson correlations. No differences were found between the first 15 min of each half for the distance completed at high-speed (>15 km.h(-1) or sprinting (>21 km.h(-1), or in the number of sprints undertaken (p>0.05). However, total distance covered was shorter (1st half vs. 2nd half: 1746±220 vs. 1644±224 m; p<0.001) and mean speed lower (1st half vs. 2nd half: 7.0±0.9 vs. 6.6±0.9 km.h(-1); p<0.001) in the first 15 min of the second half compared to the first. The correlations between the duration of the half-time interval and the difference in the high-speed running or sprinting between first and second halves (0-15 min) were very small (r=0.08 [p=0.25] and r=0.04 [p=0.61] respectively). Therefore, this study did not find any difference between the amount of high-speed running and sprinting completed by semi-professional soccer players when the first 15 min of the first and second half of competitive matches were compared The maintenance of high-speed running and sprinting, as total distance and mean speed declined, may be a function of the pacing strategies adopted by players in competitive matches.

Previous-day hypohydration impairs skill performance in elite female field hockey players.

The purpose of this study was to determine the effects of 2% hypohydration on skill performance in elite female field hockey players following intermittent exercise in the heat. Eight elite female field hockey players performed 50 min of a field hockey-specific intermittent treadmill running protocol (FHITP) in hot environmental conditions (33 °C, 60% relative humidity) in different hydration states: euhydrated (EUH) and hypohydrated by 2% body mass (HYPO). Hydration status was manipulated via a period (121±10 min) of passive hyperthermia (40 °C, 75% relative humidity) and controlled fluid intake 1 day preceding testing. Ad libitum fluid intake was permitted throughout both trials. Field hockey skill tests were performed pre- and post-FHITP. Skill performance time increased (P=0.029) in the HYPO trial compared with the EUH trial, which may be attributed to an increase in penalty time (P=0.024). Decision-making time increased (P=0.008) in the HYPO trial and was significantly impaired compared with EUH (P=0.016) pre-FHITP. Ad libitum drinking appeared to be sufficient to maintain decision-making performance as no interaction effects were evident post-FHITP. Players who commence match-play in a state of hypohydration may be susceptible to decrements in skill and decision-making performance.

Validation of a real-time video analysis system for soccer.

The aim of the current study was to determine the validity of an automated multiple-camera tracking system (Venatrack™), for the measurement of speed during soccer. 18 recreationally active males (mean age 27±8.6 years) performed a series of runs (total 391), representative of the movements made by soccer players, at given speeds. The speeds recorded by the automatic tracking system were compared statistically with speed measurements made using timing gates. For all the runs combined the mean speed recorded by the automated system was 15.4±5.5 km·h - 1 compared with the recorded mean speed of 15.2±5.4 km·h - 1 and the mean difference and 95% limits of agreement were - 0.25±0.64 km·h - 1. Pearson correlations (r) among timing gate speed and automated tracking speed were ≥ 0.99 (P<0.001), except the 20 m sprint, with 90° turn (r > 0.7). For the zig-zag shuttle the mean speed recorded by the automated system was 21.2±3.5 km·h - 1 compared with the recorded mean speed of 20.8±3.4 km·h - 1. The results demonstrate good validity over a range of soccer specific movements and speeds, up to and including sprinting. The results of this study suggest that the automated system (Venatrack™) is a valid real-time motion analysis system for tracking player movements during soccer.

Reliability of the physiological and metabolic responses to a field hockey specific treadmill protocol for elite female players.

AIM: The purpose of this study was to assess the reliability of the physiological and metabolic responses to a sport-specific treadmill protocol designed to simulate the activity pattern of elite women's field hockey match-play. METHODS: Eight elite female field hockey players completed two trials of the Field Hockey Intermittent Treadmill Protocol (FHITP) separated by 5 days. The protocol consisted of 50 min of intermittent treadmill running designed to replicate the demands of match-play. Heart rate was determined continuously using Polar Team monitors. Rectal temperature was recorded every 10 min and capillary blood samples were taken at rest, at half-time (immediately after the completion of the first half) and at the end of the protocol for analysis of blood glucose and lactate. RESULTS: Heart rate response (CV 3.5%, CI, 2.9% to 4.4%), rectal temperature (CV 0.6%, 95% CI, 0.5% to 0.8%) and blood glucose (CV 1.4%, 95% CI, 1.1% to 2.1%) were all reproducible. No systematic error was evident between trials for blood lactate response (P=0.289) to the FHITP, although the overall CV for the measurement was 14.2% (95% CI, 10.7% to 21.2%). CONCLUSION: It was concluded that the physiological and metabolic responses to the FHITP were highly reproducible with the recommendation that blood lactate concentrations are used in conjunction with heart rate or other key performance measures to assess performance.

A heat acclimation protocol for team sports.

BACKGROUND: It is well documented that heat acclimation of six or more sessions of at least 60 min duration prolongs the time to exhaustion during endurance walking, cycling and running in the heat. However, this type of acclimation is not specific to team sport activity and the effect of acclimation on prolonged high-intensity intermittent running has not yet been investigated. OBJECTIVE: To assess the impact of an intermittent acclimation protocol on distance run during team sport activity. METHODS: The impact of four short heat acclimation sessions (30-45 min of the Loughborough Intermittent Shuttle Test; LIST) on high-intensity intermittent running capacity (LIST) in the heat (30 degrees C, 27% relative humidity (RH)), was examined. Seventeen female well-trained games players were split into three groups: an acclimation group (30 degrees C, 24% RH), a moderate training group (18 degrees C, 41% RH) and a control group who did not complete any training between the main trials (pre-acclimation and post-acclimation). The pre-acclimation (A) and post-acclimation (B) trials were separated by 28 days to control for menstrual phase and verified using hormonal analysis. The four acclimation or moderate training sessions utilising the LIST were completed with one or two rest days interspersed between each session in a 10-day period prior to the post-acclimation trial (B). RESULTS: In the post-acclimation trial distance run was increased by 33% in the acclimation group (A: 7703 (SEM 1401) m vs B: 10215 (SEM 1746) m; interaction group x trial p<0.05), but was unchanged in the moderate and control groups. The acclimation group had a lower rectal temperature (interaction group x trial x time p<0.01) due to a lower rate of rise, and an increase in thermal comfort1 after acclimation (End A: 7 (SEM 2) vs 6 (SEM 2); interaction group x trial p<0.01). There was no difference in serum progesterone, aldosterone or cortisol concentrations following acclimation or between groups. CONCLUSION: Four 30-45 min sessions of intermittent exercise induced acclimation, and resulted in an improvement in intermittent running exercise capacity in female games players. A lower rectal temperature and a concomitant rise in thermal comfort may be partly responsible for the improvement in exercise capacity.

Immunohistology of normal and ovarian cancer tissue with a monoclonal antibody to placental alkaline phosphatase.

A monoclonal antibody, designated NDOG2, has been shown to react with placental alkaline phosphatase. It does not bind to liver, kidney, bone, or intestinal alkaline phosphatase enzymes and has shown a positive reaction with all of over 50 placentae. Immunohistological studies have shown (a) a reaction with respiratory bronchiolar epithelium of lung, endocervical gland epithelium, the epithelium of fallopian tube, and certain reticular cells in the thymic medulla; (b) no detectable staining with ten other normal tissues including testis and tonsil; and (c) a significant reaction with nine of 13 ovarian cystadenocarcinomas and little or no staining with four malignant ovarian tumors of other histopathological types. The NDOG2 antibody may be of value as a marker in patients with ovarian cystadenocarcinoma.

The value of immunohistological screening in the production of monoclonal antibodies.

This paper describes an immunoperoxidase technique for labelling cryostat tissue sections which is routinely used in the authors' laboratories both in the initial screening of hybridoma culture supernatants, and also during the subsequent cloning and growth of antibody-secreting cell lines. The technique can readily be performed on 100 samples in less than 3 h and is free of non-specific background labelling. The staining pattern of a monoclonal antibody on a single tissue section allows semiquantitative assessment of its reactivity against a wide variety of tissue constituents and is thus inherently much more informative than conventional screening techniques (such as binding assays) which yield only a single numerical value for each test performed. In consequence it is often possible to identify the probable specificity of a new monoclonal antibody at the primary screening stage. A further important advantage of immunohistological screening is that it detects antigens on cells or other tissue structures which do not readily enter suspension and also antibodies against nuclear and cytoplasmic antigens. Examples of monoclonal antibodies analysed by immunohistological screening include antibodies against C3b receptor, HLA-DR, factor VIII-related antigen, human syncytiotrophoblast, dendritic reticulum cells and a proliferation-associated cell surface glycoprotein.

Immunosuppressive properties of rabbit antibodies against a major glycoprotein restricted to rat leukocyte membranes.

The role of antibodies to the rat leukocyte-common (LC) antigen in the immunosuppression induced by antilymphocyte serum (ALS) was tested in two ways. First, two batches of rabbit antisera to purified rat LC antigen and a conventional rabbit anti-rat thoracic duct lymphocyte serum (ALS) were compared for their ability to suppress the rejection of LEW (RT1l) kidney grafts transplanted to DA (RT1a) recipients. All three sera were able to suppress rejection completely. However, when the amount of lymphocyte-binding immunoglobulin necessary for effective immunosuppression was compared, the anti-LC sera were found to be 10-fold weaker than the conventional ALS. In the second experiment the conventional ALS was depleted of its anti-LC antibodies by incubating with pure LC antigen, and this was found not to diminish its immunosuppressive potency. It was concluded that anti-LC antibodies do not contribute significantly to the immunosuppressive potency of conventional ALS. This is despite the fact that anti-LC antibodies constituted 48% of the antibodies in the ALS used in the immunosuppression experiments, and in six other batches of ALS the proportion of anti-LC antibodies ranged from 25 to 49%. Because only a small component of the nonanti-LC antibodies are directed at leukocyte-specific antigens, it is concluded that the immunosuppressive properties of ALS are mediated by a minor component of the serum directed at as yet undefined antigens. In additional experiments, a mouse monoclonal antibody to the rat LC antigen, a mouse monoclonal antibody (W3/13) to a rat T lymphocyte-brain-granulocyte antigen, and rabbit antisera to pure rat Thy-1 were tested for their ability to suppress kidney graft rejection, but none had any effect at all, even in large doses.

Chloral hydrate and the carbon dioxide chemoreceptor response: a study of puppies and infants.

CO2 chemoreceptor function was assessed during natural sleep and following the administration of 100 mg/kg of chloral hydrate to 26 puppies. With chloral hydrate-induced sleep, there were no significant changes in ventilation or in CO2 chemoreceptor response. The ventilation and CO2 chemoreceptor response of a group of infants in natural sleep were compared with those of a group receiving 50 mg/kg of chloral hydrate. Tidal volume O2 consumption, and CO2 elimination were slightly higher in the group given chloral hydrate. There was no difference in the CO2 chemoreceptor response. The proportion of time spent in rapid eye movement (REM) and non-rapid eye movement (NREM) sleep in chloral hydrate-induced sleep was similar to that occurring in natural sleep. Use of chloral hydrate stabilizes O2 consumption sleep. Use of chloral hydrate stabilizes O2 consumption and CO2 production, and it greatly facilitates the assessment of chemoreceptor function in infants. The CO2 chemoreceptor response appears not to be altered in puppies or infants.

Postoperative hemodynamic and electrophysiologic evaluation of the interatrial baffle procedure.

Hemodynamic and electrophysiologic studies were performed in 11 children with dextrotransposition of the great arteries an average of 26 months after the interatrial baffle procedure and, in 2 patients, additional closure of a ventricular septal defect. All children are clinically well. Right to left shunts ranging from 28 to 63 percent of systemic blood flow were found at the superior vena caval-baffle junction in four children. The superior vena caval-baffle gradient averaged 7 mm Hg (range 0 to 22). Right ventricular stroke work index averaged 39 g-m/beat per m2 and right ventricular end-diastolic pressure 9 mm Hg. These values were not significantly different from the values for the systemic left ventricle in a comparable group of normal children (average left ventricular stroke work index 45 g-m/beat per m2 and average left ventricular end-diastolic pressure 8 mm Hg). Cardiac index, heart rate and arteriovenous oxygen difference were also normal. No child has complete heart block. His bundle recording demonstrated normal H-V intervals (range 27 to 40 msec); 4 of the 11 had a prolonged A-H interval. Left ventricular systolic pressure was less than 40 mm Hg in all but two children who had significant subpulmonary stenosis. Pulmonary vascular resistance averaged 1.9 units and was decreased in all children. We conclude that up to 37 months postoperatively, despite some residual abnormalities, the clinical and hemodynamic condition of these children is excellent.

An immunoelectron microscopic study of human placenta using three monoclonal antibodies.

An immunoelectron microscopic technique was used to analyse the distribution in term human placentae at the ultrastructural level of three antigens recognized by recently developed monoclonal antibodies. Two of the antigens (recognized by NDOG-1 and NDOG-2) were present only on the outer villous membrane of the syncytiotrophoblast. The other (HLA-A, B, C) was absent from syncytiotrophoblast and present on some capillary endothelial cells and on Hofbauer cells in the villous stroma.

Complex of secundum atrial septal defect and congestive heart failure in infants.

Five infants with intractable congestive heart failure due to ostium secundum atrial septal defect (ASD) are presented. All survived ASD closure and are doing well. Correction of this defect in infancy should be considered when medical therapy is unsuccessful.

Aortico-left ventricular tunnel. Recognition and repair in infancy.

An infant with an aortico-left ventricular tunnel underwent surgery at the age of five months. There was clinical and electrocardiographic improvement, and postoperative cardiac catheterization demonstrated obliteration of the aortic end of the tunnel, normalization of systemic pulse pressure, mild residual aortic valvular insufficiency, and a decrease in the left ventricular end-diastolic volume index. Early surgery may limit the progression of aortic valvular insufficiency secondary to turbulent aortic-root blood flow.

Influence of age at operation on late results with subclavian flap aortoplasty.

Despite the popularity of subclavian flap aortoplasty for repair of aortic coarctation, reported experience and follow-up in neonates is surprisingly limited. This paucity of reports prompted this review of age-related late recurrence rates. Of 83 patients having subclavian flap aortoplasty from 1976 to 1983, 60 were less than 8 weeks of age at operation (mean 2.6 weeks). Operative and late mortality were 18% and 14%, respectively. After a mean follow-up of 26 months, 10 patients have experienced recurrent coarctation (a mean of 10 months elapsed between operations). For 23 patients older than 8 weeks of age at operation (mean 20 months), operative and late mortality were 13% and 10%, mean follow-up is 16 months, and no patient has yet experienced recurrence. Thus, 75% of infants less than 8 weeks of age at operation are free of recoarctation at 2 years, and 100% of older children are free of recoarctation at 2 years (p = 0.06). Review of the literature corroborates our findings. The difference in recurrence rates may be due to age-dependent involution of residual coarctation tissue unavoidably left in place during subclavian flap aortoplasty. We conclude that subclavian flap aortoplasty is effective for correction of coarctation in infants, but patients less than 8 weeks old have a significant risk of early recurrence. Based on this review and our recently reviewed experience with end-to-end anastomosis, our preference is to use the latter in this age group when technically feasible.

Valvotomy for pulmonary atresia with intact ventricular septum. A disciplined approach to achieve a functioning right ventricle.

During the past 20 years, a consistent policy in applying early valvotomy has resulted in a unique opportunity to appraise the long-term results of this approach in pulmonary atresia with intact ventricular septum. Since 1964, 27 of 35 patients with pulmonary atresia with intact ventricular septum had type 1 or 2 right ventricle, 25 of these had early valvotomy, seven with and 18 without concomitant shunt. The remaining two patients with type 2 right ventricle and the eight patients with type 3 right ventricle received a shunt alone. Overall operative mortality was 34%; for those patients weighing more than 3 kg and those operated upon since 1977, it was 18% and 16%, respectively. There were 17 survivors of early valvotomy: 11 had valvotomy alone and six had valvotomy with shunt; 12 had type 1 right ventricle and five had type 2 right ventricle. Survival rates (+/- standard error) for these 17 patients were 85% +/- 10% and 68% +/- 17% at 5 and 10 years, respectively. The probability of reoperation was 100% by 6 years of age; outflow patch reconstruction was employed in all patients in whom reoperation has been performed. Aggressive follow-up and early recatheterization were essential features of management. Delayed reconstruction after shunt alone was unsuccessful in three patients. Primary valvotomy without shunt is the operation of choice for patients with pulmonary atresia with intact ventricular septum and type 1 right ventricle. Concomitant shunt may be required for some patients with type 1 and most with type 2 right ventricle, selected preoperatively by angiography or after valvotomy by clinical necessity. Delayed right ventricular reconstruction after shunt alone is not an acceptable approach when an outflow tract is present.

Coarctation of the aorta in patients younger than three months. A critique of the subclavian flap operation.

Unexpected and disappointing late results with the subclavian flap operation prompted this analysis of repair of coarctation in infants under 3 months of age. A total of 134 such patients underwent surgical repair since 1960 with 55 end-to-end anastomoses performed earlier in our experience (mean follow-up 5.0 years) and 67 subclavian flap angioplasty operations performed more recently (mean follow-up 2.0 years). The operative mortality was not significantly different (p = 0.3) between end-to-end anastomosis (29%) and subclavian flap angioplasty (19%), but it was significantly higher (p less than 0.01) in the first week of life (56%). Recurrent coarctation occurred in 16 cases, necessitating reoperation. The reoperation-free rates (with standard error) at 5 years for end-to-end anastomosis and subclavian flap angioplasty were 92% +/- 5% and 75% +/- 7%, respectively (p = 0.01). Eight of 10 patients who had reoperation after angioplasty had early recurrence with continued involution of the periductal tissues and growth of the posterior aortic ridge. Six patients who had recurrence after anastomosis demonstrated late anastomotic growth failure. The most common reoperation technique was patch aortoplasty (10 patients). The high incidence of early recurrence with subclavian flap angioplasty in infants under 3 months of age suggests end-to-end anastomosis as the procedure of choice when applicable.

Mitral repair in complete atrioventricular canal. Ease of correction in early infancy.

During the past 5 years all patients with complete atrioventricular (AV) were subjected to surgical correction regardless of age. Thus we were able to assess the ease and reliability of mitral repair in early infancy. Key features of operation include division of bridging leaflets when indicated, selection of a patch sufficiently small to prevent postoperative annular dilation, attachment of the leaflets to the patch with continuous nonpledget-supported sutures at a level determined by the chordal structure, and, based on the size of the mural leaflet, construction of a bicuspid or tricuspid mitral valve. Operative mortality and postoperative morbidity were no greater in patients under 6 months of age than in older patients. Reoperation for mitral regurgitation was required in three patients. In all of them, the primary reason for the failure of repair was that the mitral valve had been left tricuspid; in two of them, the mitral anulus was dilated, as well. Repair was uniformly accomplished by bicuspidization, combined in two instances with a Wooler-type annuloplasty and shortening of the free margin of the aortic leaflet. The absence of secondary scarring of the leaflets in the patients under 6 months of age facilitated repair in this age group. Early repair is possible, and preferable, provided that meticulous attention is paid to the technical features of the repair and a proper decision is made with regard to treatment of the mitral "cleft."