The effects of gestational age on neonatal cholestasis: A retrospective cohort study.

BACKGROUND: Reference guidelines for neonatal conjugated hyperbilirubinemia (cholestasis) management use a uniform approach regardless of gestational age (GA). We hypothesize that the clinical pattern of neonatal cholestasis is tightly related to GA. The aim of this study was to describe the effects of GA on neonatal cholestasis. METHODS: A retrospective 4-year cohort study in a 70-bed neonatal care unit. Neonates with conjugated bilirubin≥34.2µmol/L (2 mg/dL) were identified. The incidence, clinical characteristics, etiology, treatment, and prognosis were compared between infants <32 and≥32 weeks GA. RESULTS: Overall incidence of cholestasis was 4% (125/3402). It was >5 times higher and the mean duration was >1.5 times longer in neonates <32 weeks GA (10% versus 1.8%, p <0.01 and 49 versus 31 days, p <0.01, respectively). The onset of cholestasis was later in neonates <32 weeks (22 versus 10 days of life, p <0.001). This later onset of cholestasis was associated with parenteral nutrition, whereas the earlier onset was associated with other causes. Treatment using fish oil lipids was more frequently administrated to infants <32 weeks GA, whereas Ursodeoxycholic acid was administrated more frequently in≥32 weeks GA. Cholestasis resolved during hospitalization in 73% of <32 versus 38% in≥32 weeks GA infants (p <0.01). CONCLUSIONS: The incidence, clinical presentation, etiology, treatment, and clinical evolution of neonatal cholestasis were all significantly affected by GA. Our results support the use of a GA-oriented approach for the management of neonatal cholestasis.

Placental oxidative stress in a rat model of preeclampsia.

The onset of preeclampsia is associated with increased maternal insult that could affect placental function. By increasing sodium intake (0.9% or 1.8% NaCl in drinking water) during the last week of gestation in the rat, we developed an animal model that shows many characteristics of preeclampsia such as increased blood pressure, decreased circulatory volume and diminished activity of the renin-angiotensin-aldosterone system. The aim of the present study was to determine in this model whether maternal perturbations in pregnancy lead to placental oxidative stress. Sprague-Dawley pregnant rats receiving salted-water were compared to not-supplemented pregnant rats. Markers of oxidative stress, ensuing cell death, and changes in the production of vasoactive substances (prostanoids: thromboxane, TxB(2); and prostacyclin, PGF(1alpha)) and the pro-inflammatory cytokine tumour necrosis factor-alpha (TNF-alpha) were measured in the placenta. In tissue from pregnant rats on 1.8% NaCl supplement, 8-iso-PGF(2alpha) levels, TxB(2)/6-keto-PGF(1alpha) ratios, total TNF-alpha RNA expression, as well as the apoptotic index (Bax/Bcl-2 ratio) and endothelial nitric oxide synthase protein expression increase while total glutathione content decreases. These findings demonstrate that maternal insult during gestation induced an imbalance in the oxidative environment in the placenta favouring oxidation. This was accompanied by an increased synthesis of vasoconstrictive substances and TNF-alpha by the placenta as well as the increased rate of placental cell apoptosis.

Myeloablative allografting for chronic lymphocytic leukemia: evidence for a potent graft-versus-leukemia effect associated with graft-versus-host disease.

In all, 30 patients with CLL proceeded to myeloablative allogeneic BMT using related (n=20, 67%) or unrelated (n=10) donors, at the Princess Margaret Hospital (Toronto) (n=20) or the Leukemia/BMT Program of BC (Vancouver) (n=10), from 1989 to 2001. Median (range) interval from diagnosis to BMT was 4.8 (0.3-13) years, median number of prior therapies was three and median age 48 years. The preparative regimen included total body irradiation in 15 (50%). In all, 14 of 30 patients (47%) are alive, with median (range) follow up of 4.3 (2.4-10.5) years. All are in complete remission, two following therapy for post-BMT progression. Actuarial overall (OS) and event-free survival (EFS) at 5 years is 39% (OS 48% for related donor and 20% for unrelated donor BMT); cumulative incidence of nonrelapse mortality (NRM) and relapse is 47 and 19%, respectively. Both acute (RR=0.008, P=0.01) and chronic (RR=0.006, P=0.02) Graft-versus-host disease (GVHD) were associated with markedly decreased risk of relapse. Patients receiving grafts from unrelated donors had increased NRM (RR=3.6, P=0.02) and decreased OS (RR of death=3.4, P=0.002). Allogeneic BMT has resulted in long-term EFS in approximately 40% of patients with CLL. There is evidence for a strong graft-versus-leukemia effect associated with acute and chronic GVHD, resulting in near complete protection from relapse.

Oxygen and parenteral nutrition two main oxidants for extremely preterm infants: 'It all adds up'.

OBJECTIVES: To assess the effect of early exposure to O2 and parenteral nutrition (PN) on oxidative stress at 36 weeks post-menstrual age (PMA) and on bronchopulmonary dysplasia (BPD) in extremely preterm infants. STUDY DESIGN: A prospective observational study including 116 infants <29 weeks of gestation. Baseline clinical characteristics, FiO2 on day 7, duration of PN and clinical outcomes data were collected. In 39 infants, whole blood glutathione (GSH) and oxidized glutathione (GSSG) at 36 weeks PMA were measured and the redox potential was calculated using Nernst equation. Student's t-test, Chi-square, Spearman correlation, ANOVA, and logistic regression analyses were used as appropriate. P <  0.05 was considered significant. RESULTS: FiO2 ≥25% was associated with higher level of GSSG (0.29 ± 0.04 versus 0.18 ± 0.02 nmol/mg of protein), a more oxidized redox potential (-191 ± 2 versus -198 ± 2 mV) and more BPD (90% versus 45%). PN duration >14 days was also associated with higher level of GSSG (0.26 ± 0.03 versus 0.13 ± 0.02 nmol/mg of protein), a more oxidized redox potential (-193 ± 5 versus -203 ± 2 mV) and more BPD (89% versus 24%). In logistic regression model, each 1% increase in FiO2 and each day increase in PN duration resulted in an increase in the OR for BPD by 1.57 (1.09 -2.28) and 1.17 (1.03 -1.33) respectively. CONCLUSION: Early O2 supplement and PN have additive effects that were associated with prolonged oxidative stress and increased risk of BPD. Strategies targeting judicious use of O2 and decreasing the duration or developing a safer formulation of PN can be targeted to decrease BPD.

Kinetic studies on the formation of estrogens from dehydroepiandrosterone sulfate by human placental microsomes.

Using microsomes isolated from term human placentae kinetic analyses of each of the enzymes involved in estrogen synthesis from dehydroepiandrosterone sulfate have been carried out and the following parameters were found: sulfatase, Michaelis-Menten constant (Km) = 16,000 +/- 5,000 nM, maximum velocity (Vm) = 2.0 +/- 0.5 nmol X min-1 X mg protein-1; 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), Km = 15 +/- 3 nM, Vm = 1.8 +/- 0.4 nmol X min-1 X mg protein-1; aromatase, Km = 14 +/- 4 nM, Vm = 0.12 +/- 0.02 nmol X min-1 X mg protein-1. From these values one can predict that, theoretically, the rate-limiting enzyme in estrogen synthesis from dehydroepiandrosterone sulfate (DS) should change from the sulfatase at low concentrations of substrate to the aromatase at higher concentrations. In order to test this hypothesis we developed a system which allowed the formation of estrogens from DS, dehydroepiandrosterone, and androstenedione to be measured and the appropriate intermediates to be isolated. The sulfatase was found to be rate limiting at concentrations of DS below 2 microM and the aromatase was found to be rate limiting at higher concentrations. These data may explain why previous perfusion studies of human placentae indicated the sulfatase was the rate-limiting enzyme in estrogen synthesis yet in vitro studies found that it was the aromatase. Steroids previously shown to inhibit the 3 beta-HSD were examined for their ability to inhibit the formation of estrogens from DS. Although 3 beta-HSD activity was markedly inhibited this had little effect on the overall conversion of DS to estrogens, until high concentrations of inhibitors were used. The data also underline the importance of studying enzyme systems rather than single enzymes when studying steroid synthesis.

Primary culture of cells from human chorion laeve: steroid metabolism and properties of cells grown in defined media supplemented with 0.1% or 10% fetal calf serum.

The purpose of this study was to develop primary cultures of human chorion laeve cells and examine certain aspects of steroid metabolism during culture. Tissues obtained by elective cesarean section at term (38-40 weeks) were dispersed with collagenase. Cells were isolated on Percoll gradients at the interface between 20% and 40% Percoll and examined in primary culture for up to 1 week. Cultures were carried out in chemically defined media supplemented with 10% or 0.1% fetal calf serum (FCS). The morphological and biochemical properties of the cells were different in the two systems. In 0.1% FCS, cells formed clumps of tissue within 16 h of plating, and there was no cell replication. In contrast, in 10% FCS, the cells formed a carpet of tissue and reached confluence after 5 days in culture, resulting in increased DNA and protein content and thymidine incorporation in the dishes. Three steroidogenic enzymes were studied during culture: alkyl steroid sulfatase, estrogen sulfatase and 3 beta-hydroxysteroid dehydrogenase. The sulfatases had higher activities in 0.1% than in 10% FCS, and their activities decreased markedly during the culture period. In contrast, 3 beta-hydroxysteroid dehydrogenase activity was higher in 10% FCS than in 0.1% FCS. Activity remained constant during the culture period in 0.1% FCS and increased in 10% FCS. In the latter system this increase resulted in the enzyme maintaining a constant specific activity during culture. These studies describe two viable systems of chorion laeve cells in primary culture, which may be valuable for studying long term and/or subtle effects on various metabolic aspects of this tissue.

Gender and maturation affect glutathione status in human neonatal tissues.

Gender and maturation affect glutathione status in human neonatal tissues. The objective was to verify if human tissues derived from baby girls had a greater ability then tissues derived from males to stimulate the glutathione-reductase, when faced with an oxidative challenge. In vitro, the effect of a calibrated oxidative challenge was studied in endothelial cells. In vivo, the effect of a clinically relevant oxidative challenge was studied in cells from tracheal aspirates derived from oxygen-dependent newborn infants. In endothelial cells, the oxidant tert-butylhydroperoxide had a stimulating effect on GSSG-R activity in cells derived from females. The peroxide produced a time, concentration and gender-dependent cytotoxicity, with female-derived cells exhibiting a better viability. In vivo, the intracellular total glutathione content was higher in female-derived cells and in cells from more mature babies; postnatal age and gestational age had a positive effect on the activity of GSSG-R. Oxygen (FiO2 > or = 0.3) was associated with a lower activity of GSSG-R in boys, early in life. Considering that glutathione is a central element in the antioxidant defense, these results suggest that specific tissues derived from the baby girl are potentially better protected against an oxidative stress than those derived from the boy.

Development of glutathione synthesis and gamma-glutamyltranspeptidase activities in tissues from newborn infants.

Following the observation that the level of glutathione in leukocytes from human newborn infants was lower in preterm and in male infants, a study was designed to document the level of activities of glutathione synthesis and gamma-glutamyltranspeptidase during the development of preterm and term newborn infants. Measurements were performed in leukocytes from tracheal aspirates of oxygen dependent infants, and in leukocytes from cord blood. Contrary to the common belief concerning the development of antioxidant activity, the biosynthesis of glutathione was active in leukocytes from preterm infants; and by two days of life the activity of gamma-glutamyltranspeptidase reached 3 times the level of that seen in cord blood. Our results suggest that the maturity of these enzymes was not the limiting step in maintaining cellular glutathione levels. This represents new information concerning the maturation of a central antioxidant in tissue derived from preterm and term human newborn infants at risk of oxidant stress. This implies that sources of cysteine crossing freely the cellular membrane could be used by tissues of term and preterm infants to produce glutathione.

The increase in vasomotor tone induced by a parenteral lipid emulsion is linked to an inhibition of prostacyclin production.

The aim of the study was to verify whether the infusion of a lipid emulsion causes a rise in vascular pressure related to an imbalance in the production of vasoconstricting and vasodilatating eicosanoids. Segments of umbilical veins were perfused with and without 1.5 microM indomethacin (cyclooxygenase inhibitor) in solutions differing only in their lipid content (control vs. lipid). The lipid-induced higher pressure (p < 0.05) was associated with an inhibition (p < 0.05) in the output of the vasodilatator PGI2, and an increase (p < 0.01) in the production of the vasoconstrictor PGF2 alpha. Indomethacin abolished differences in pressure, but produced a rise (p < 0.01) in vascular tone of both the control and lipid-containing solutions by inhibiting PGI2 synthesis. Prostacyclin was the only eicosanoid significantly correlated (p < 0.01) to vascular tone. The lipid emulsion was therefore linked to the inhibition of the conversion of PGH2 to PGI2. The ensuing greater PGH2 availability would result in vivo, in the increased synthesis of vasoconstricting eicosanoids. The lipid-containing solution produced vasoactive responses similar to those reported with tert-butyl hydroperoxide, suggesting that hydroperoxides contaminating commonly used lipid emulsions could be causing a prostanoid-dependent vasoconstriction.

Gender-related response to a tert-butyl hydroperoxide-induced oxidation in human neonatal tissue.

Reports of gender-related differences in the activity of enzymes involved in the metabolism of intracellular antioxidants, led us to verify whether the prostaglandin response to tert-butyl hydroperoxide (TBH) differed according to the sex of infants. Segments of human umbilical veins were perfused in the presence or absence of TBH (0.25 mmol/l, and 1.0 mmol/l). Because TBH is quenched in the cell by glutathione peroxidase, total glutathione concentrations and production of glutathione-dependent prostaglandins (PGE2 and PGF2 alpha) as well as membrane-derived eicosanoids (PGI2 and thromboxane) were measured in the eluate. In veins from boys, TBH induced a sustained response for glutathione only, which was increased (p < 0.05). In female-derived tissue, the hydroperoxide induced a different response according to the dose of TBH. At 0.25 mmol/l, a drop (p < 0.005) in PGF2 alpha was associated with a rise (p < 0.001) in thromboxane. At 1.0 mmol/l, TBH had an opposite effect--there was a rise (p < 0.01) in PGE2 and PGI2. The prostaglandin concentration were not proportional to the oxidative stimulus, suggesting a critical level of TBH at which the oxidative state differs in tissues derived from boys or girls.

N-acetylcysteine in pig liver transplantation from non-heart-beating donors.

Lipid peroxidation due to oxygen free radicals (OFR) seems to play a major role in loss of liver graft viability after warm ischemia, preservation, and transplantation. N-acetylcysteine (NAC) is an antioxidant that has a direct effect on OFR, and is also a glutathione precursor, another antioxidant. This study was designed to evaluate the efficacy of NAC in preventing ischemia-reperfusion damage of liver grafts harvested from non-heart-beating donors. Liver transplantation was performed on pigs divided into five groups: group 1 (control group; n=5) received livers from heart-beating donors; livers were subjected to 30 min of warm ischemia in groups 2 (n=3, no NAC) and group 3 (n=3; NAC treatment); warm ischemia time lasted 60 min in groups 4 (n=4; no NAC) and 5 (n=5; NAC treatment). Studied parameters included graft survival for more than 3 days, aspartate aminotransferase plasma levels, liver histology, and hepatic total glutathione concentrations. Graft survival was 100% in groups 1, 2, and 3, 0% in group 4, and 20% in group 5. NAC treatment did not influence initial mean aspartate aminotransferase release which was greater in warm ischemic livers than in controls. NAC treatment had no effect on liver hepatic total glutathione after reperfusion of animals receiving warm ischemic grants. Finally, no effect on liver histology was observed with NAC treatment. Our study suggests that in liver transplantation from non-heart-beating donors, NAC has no effect in both graft viability and lipid peroxidation. The role of OFR in primary dysfunction of transplanted warm ischemic livers remains controversial.

Antiperoxide activity of sodium metabisulfite. A double-edged sword.

Sulfites are chemical substances that are used widely in the pharmaceutical industry to reduce or prevent oxidation. Sodium metabisulfite (Na2S2O5) is still present in several parenteral amino acid solutions. Since intravenous lipid emulsions are contaminated by hydroperoxides, we evaluated whether metabisulfite had an antioxidant activity against hydroperoxides. In vitro, Na2S2O5 inhibited the oxidant activity of H2O2, tert-butyl-, and cumene hydroperoxides. The antioxidant capacity of metabisulfite was supported in vivo by the lower (P < 0.01) excretion of malondialdehyde, a stable end product of lipid peroxidation, in babies receiving metabisulfite in their parenteral nutrition. However, for concentrations outside the range found in solutions for parenteral nutrition, the reduction of hydroperoxides by Na2S2O5 could transform this compound into an oxidant, like a sulfite radical. It is suggested that metabisulfite has antiperoxide properties that, under specific conditions, contribute to the generation of toxic oxidants.

Peroxide-like oxidant response in lungs of newborn guinea pigs following the parenteral infusion of a multivitamin preparation.

The multivitamin solution is a major component responsible for the photo-induced generation of peroxides in parenteral nutrition. The lung is a target of oxidant injury; however, the specific role of infused peroxides is unknown. The aim of this study was to determine if parenteral multivitamins induce in the lung an oxidant challenge similar to that of peroxides. Newborn guinea pigs were infused with dextrose plus relevant concentrations of H(2)O(2) (0,250,500 microM) or multivitamins (0,1%), as well as parenteral nutrition supplemented with multivitamins (0,1%). After 4 days, total glutathione, glutathione-related enzymes, and oxidant-sensitive eicosanoids were measured in the lungs. Peroxides as well as multivitamins led to a significant decrease in glutathione and the activity of glutathione synthase, indicating that infused peroxides were not entirely transformed into free radicals, which would have stimulated glutathione synthesis. The multivitamin solution induced a response in oxidant-sensitive eicosanoids similar to the response to peroxides, suggesting an oxidant stress that was not alleviated by the antiradical properties of its components. The effects on prostaglandins occurred independently from the stimulation in glutathione levels induced by parenteral nutrition. The multivitamin solution carries an oxidant load and causes effects similar to those of peroxides in the lungs of newborn guinea pigs.

Characteristics and outcome of patients developing endocarditis following hematopoietic stem cell transplantation.

Endocarditis is an uncommon complication of hematopoietic stem cell transplantation (HSCT). A retrospective review of 1547 patients who underwent HSCT in Vancouver between January 1986 and December 2001 was performed. In all, 20 cases of endocarditis were identified (1.3% of all patients) with nine patients having received cryopreserved autologous stem cells, six stem cells from a histocompatible sibling and five patients stem cells from an unrelated donor. Five patients had endocarditis diagnosed while alive, a median of 6 months post-HSCT, by transthoracic (four patients) or transesophageal (one patient) echocardiography. The remaining 15 cases of endocarditis were only identified post mortem. The mitral valve was the most frequently involved (10 patients) followed by the aortic valve (six patients); multivalvular disease was noted in five patients. Of the 11 affected allogeneic HSCT patients, 10 had previously developed acute graft-versus-host disease (GVHD). Causative organisms were identified in 11 patients, while nine additional cases were felt to be thrombotic in origin. Of the 20 patients, 19 died with the sole survivor alive 10 years following an aortic valve replacement. Endocarditis is an uncommon complication of HSCT usually involving the cardiac valves on the left side of the heart and is associated with a high mortality rate.

Second malignancy following high-dose therapy and autologous stem cell transplantation: incidence and risk factor analysis.

To establish incidence and risk factors for development of second malignant neoplasms after high-dose chemo/radiotherapy (HDT) and autologous hematopoietic stem cell transplantation (AHSCT), the case files of 800 consecutive patients who underwent AHSCT at our institution between June 1982 and December 2000 were reviewed. In all, 26 patients developed 29 second malignancies (nine myelodysplastic syndrome (MDS)/acute myelogenous leukemia (AML), 16 solid tumors and four lymphoproliferative disorders (LPDs)) for a 15-year cumulative incidence of 11% (95% confidence interval (CI), 5-18%). These second tumors occurred at a median of 68 (range 1.5-177) months following AHSCT. The relative risk (RR) compared to the general population of developing a second malignancy following AHSCT was 3.3 (CI 2.2-4.7) P<0.001. The RR of developing MDS/AML, LPD and a solid tumor was 47.2 (CI 21.5-89.5) P<0.001, 8.1 (2.2-20.7) P=0.002 and 1.98 (1.1-3.2) P=0.009, respectively. In multivariate analysis, age >or=35 years at the time of AHSCT (P=0.001) and an interval from diagnosis to AHSCT >or=36 months (P=0.03) were associated with a greater risk of developing a second malignancy. Patients who have undergone HDT and AHSCT are at significant risk for developing a second malignancy and should receive indefinite follow-up.

Acute myelogenous leukemia complicated by acute necrotizing ulcerative gingivitis due to Aspergillus terreus.

Infections caused by Aspergillus terreus are rare but have been associated with a poor outcome in immunocompromised patients due to frequent resistance to conventional antifungal therapy. This report describes a case of a woman who developed acute necrotizing ulcerative gingivitis (ANUG) due to A. terreus during induction chemotherapy for acute myelogenous leukemia. She initially failed to respond to treatment with amphotericin B but the infection resolved following the introduction of oral itraconazole. Opportunistic infections caused by A. terreus are an emerging problem and can be associated with a high mortality rate. Early microbiological diagnosis is critical since resistance to amphotericin B is likely and itraconazole appears to be an effective treatment for this infection.

Photoprotection of solutions of parenteral nutrition decreases the infused load as well as the urinary excretion of peroxides in premature infants.

Light exposure and multivitamins are contributing factors to the generation of peroxides in solutions of parenteral nutrition. This article verifies if peroxides infused with parenteral nutrition are of biological significance in neonates. The mechanisms responsible for the generation of peroxides in total parenteral nutrition solutions are reviewed. The consequences of infused peroxides on an index of oxidant stress and on levels of a central antioxidant are evaluated in an animal model. The effect of photoprotection of parenteral nutrition on a biological marker of redox imbalance is evaluated in the urine of premature infants. Parenteral multivitamins produce a drop in glutathione and an oxidant stress similar to peroxides in the lungs of newborn guinea pigs. Infused peroxides elicited an increased urinary peroxide excretion in infants receiving parenteral nutrition exposed to light. Photoprotection reduced levels of infused and excreted peroxides. The results suggest that peroxides infused with total parenteral nutrition are not fully quenched by premature infants.

Substrate specificity of the placental microsomal aromatase.

Using an accurate and sensitive assay for the human placental aromatase we have found apparent Km values for androstenedione (4-androstene-3,17-dione) and testosterone to be 14 +/- 4.0 nM and 41 +/- 12 nM respectively. These values were significantly different (p < 0.001). Analyses at substrate concentrations 5-10 fold above and below the Km values did not indicate any anomalous kinetic behavior. Mixed substrate experiments were consistent with a single enzyme metabolizing both steroids: each competitively inhibited the aromatization of the other, and the "Ki" values were the same as their apparent Km values. Sodium chloride (1.2M) significantly increased the rate of testosterone aromatization by decreasing its Km value and had no significant effect on the aromatization of androstenedione. However, in the presence of this salt testosterone still inhibited the aromatization of androstenedione competitively with a "Ki" equal to its apparent Km. Our data is therefore consistent with the proposal that human placental microsomes contain a single "high affinity" site for the aromatization of androstenedione and testosterone.

3beta-Hydroxysteroid dehydrogenase activity in human fetal membranes.

A 3beta-hydroxysteroid dehydrogenase (3betaHSD) was demonstrated in term human fetal membranes (chorion and amnion) with both dehydroepiandrosterone (3beta-hydroxy-5-androsten-17-one) and pregnenolone (3beta-hydroxy-5-pregnen-20-one as substrates, and the subcellular distribution substrate and nucleotide specificity of the enzyme was studied. In both membranes the microsomal fraction (particles which sedimented at 105,000 g after 90 min) had the highest specific activity. The chorion was more active than the amnion but the enzyme in both tissues had similar substrate and nucleotide specificity. NAD was the preferred cofactor, and pregnenolone was a better substrate than dehydroepiandrosterone in the presence of NAD. However, with NADP as cofactor both steroids were equally good substrates. When the 3beta-hydroxysteroid dehydrogenase activity of chorion microsomes was compared with that of placental microsomes, the specific activities were found to be of the same order of magnitude, and the substrate, nucleotide specificity and steroid binding properties were almost identical.

Physiological training effects of playing youth soccer.

The purpose of this investigation was to determine if a 9-wk youth soccer program had any effect on cardiorespiratory fitness (VO2max and VO2submax), peak knee torque, and flexibility. Subjects were 20 sixth grade boys, 11 of whom were members of a YMCA soccer team: 9 were normally active boys who were not participating in any organized sport during the study who served as a control group. Mean ages (+/- SD) were 11.8 +/- 0.34 and 11.5 +/- 0.60 yr for the soccer and control group, respectively. Initial VO2max values of 49.83 and 47.42 ml . kg-1 . min-1 for the soccer and the control group, respectively, are similar to those reported in the literature for untrained normal boys of this age. Results indicated that playing soccer three times weekly increased VEmax and reduced VO2 (ml . kg-1 . min-1 and 1 . min-1) at a submaximal running speed (all P's less than 0.05), while no change in VO2max was noted. No significant training effect was observed in peak knee torque or flexibility subsequent to soccer training. It is concluded that the effects of playing soccer in these subjects resulted in no change in cardiorespiratory fitness, peak knee torque, or flexibility.