Is Lactoferrin More Effective in Reducing Late-Onset Sepsis in Preterm Neonates Fed Formula Than in Those Receiving Mother's Own Milk? Secondary Analyses of Two Multicenter Randomized Controlled Trials.

BACKGROUND: Lactoferrin is the major antimicrobial protein in human milk. In our randomized controlled trial (RCT) of bovine lactoferrin (BLF) supplementation in preterm neonates, BLF reduced late-onset sepsis (LOS). Mother's own milk (MM) contains higher concentrations of lactoferrin than donor milk or formula, but whether BLF is more effective in infants who receive formula or donor milk is uncertain. AIM: To evaluate the incidence of LOS in preterm infants fed MM and in those fed formula and/or donor milk. STUDY DESIGN: This is a (A) post hoc subgroup analysis, in our RCT of BLF, of its effects in preterm infants fed MM, with or without formula, versus those fed formula and/or donor milk (no-MM) and (B) post hoc meta-analysis, in our RCT of BLF and in the ELFIN (Enteral Lactoferrin in Neonates) RCT, of the effect of BLF in subgroups not exclusively fed MM. RESULTS: (A) Of 472 infants in our RCT, 168 were randomized to placebo and 304 were randomized to BLF. Among MM infants, LOS occurred in 22/133 (16.5%) infants randomized to placebo and in 14/250 (5.6%) randomized to BLF (relative risk or risk ratio (RR): 0.34; relative risk reduction (RRR): 0.66; 95% confidence interval (95% CI) for RR: 0.18-0.64; p < 0.0008). Among no-MM infants, LOS occurred in 7/35 (20.0%) randomized to placebo and in 2/54 (3.7%) randomized to BLF (RR: 0.19; RRR: 0.81; 95% CI for RR: 0.16-0.96; p = 0.026). In multivariable logistic regression analysis, there was no interaction between BLF treatment effect and type of feeding (p = 0.628). (B) In 1,891 infants not exclusively fed MM in our RCT of BLF and in the ELFIN RCT, BLF reduced the RR of LOS by 18% (RR: 0.82; 95% CI: 0.71-0.96; p = 0.01). CONCLUSION: Adequately powered studies should address the hypothesis that BLF is more effective in infants fed formula or donor milk than those fed MM. Such studies should evaluate whether a specific threshold of total lactoferrin intake can be identified to protect such patients from LOS.

Exposure to Gastric Acid Inhibitors Increases the Risk of Infection in Preterm Very Low Birth Weight Infants but Concomitant Administration of Lactoferrin Counteracts This Effect.

OBJECTIVE: To investigate whether exposure to inhibitors of gastric acidity, such as H2 blockers or proton pump inhibitors, can independently increase the risk of infections in very low birth weight (VLBW) preterm infants in the neonatal intensive care unit. STUDY DESIGN: This is a secondary analysis of prospectively collected data from a multicenter, randomized controlled trial of bovine lactoferrin (BLF) supplementation (with or without the probiotic Lactobacillus rhamnosus GG) vs placebo in prevention of late-onset sepsis (LOS) and necrotizing enterocolitis (NEC) in preterm infants. Inhibitors of gastric acidity were used at the recommended dosages/schedules based on the clinical judgment of attending physicians. The distribution of days of inhibitors of gastric acidity exposure between infants with and without LOS/NEC was assessed. The mutually adjusted effects of birth weight, gestational age, duration of inhibitors of gastric acidity treatment, and exposure to BLF were controlled through multivariable logistic regression. Interaction between inhibitors of gastric acidity and BLF was tested; the effects of any day of inhibitors of gastric acidity exposure were then computed for BLF-treated vs -untreated infants. RESULTS: Two hundred thirty-five of 743 infants underwent treatment with inhibitors of gastric acidity, and 86 LOS episodes occurred. After multivariate analysis, exposure to inhibitors of gastric acidity remained significantly and independently associated with LOS (OR, 1.03; 95% CI, 1.008-1.067; P = .01); each day of inhibitors of gastric acidity exposure conferred an additional 3.7% odds of developing LOS. Risk was significant for Gram-negative (P < .001) and fungal (P = .001) pathogens, but not for Gram-positive pathogens (P = .97). On the test for interaction, 1 additional day of exposure to inhibitors of gastric acidity conferred an additional 7.7% risk for LOS (P = .003) in BLF-untreated infants, compared with 1.2% (P = .58) in BLF-treated infants. CONCLUSION: Exposure to inhibitors of gastric acidity is significantly associated with the occurrence of LOS in preterm VLBW infants. Concomitant administration of BLF counteracts this selective disadvantage. TRIAL REGISTRATION: isrctn.org: ISRCTN53107700.

Sustained lung inflation at birth for preterm infants: a randomized clinical trial.

BACKGROUND: Studies suggest that giving newly born preterm infants sustained lung inflation (SLI) may decrease their need for mechanical ventilation (MV) and improve their respiratory outcomes. METHODS: We randomly assigned infants born at 25 weeks 0 days to 28 weeks 6 days of gestation to receive SLI (25 cm H2O for 15 seconds) followed by nasal continuous positive airway pressure (nCPAP) or nCPAP alone in the delivery room. SLI and nCPAP were delivered by using a neonatal mask and a T-piece ventilator. The primary end point was the need for MV in the first 72 hours of life. The secondary end points included the need for respiratory supports and survival without bronchopulmonary dysplasia (BPD). RESULTS: A total of 148 infants were enrolled in the SLI group and 143 in the control group. Significantly fewer infants were ventilated in the first 72 hours of life in the SLI group (79 of 148 [53%]) than in the control group (93 of 143 [65%]); unadjusted odds ratio: 0.62 [95% confidence interval: 0.38-0.99]; P = .04). The need for respiratory support and survival without BPD did not differ between the groups. Pneumothorax occurred in 1% (n = 2) of infants in the control group compared with 6% (n = 9) in the SLI group, with an unadjusted odds ratio of 4.57 (95% confidence interval: 0.97-21.50; P = .06). CONCLUSIONS: SLI followed by nCPAP in the delivery room decreased the need for MV in the first 72 hours of life in preterm infants at high risk of respiratory distress syndrome compared with nCPAP alone but did not decrease the need for respiratory support and the occurrence of BPD.

Bovine lactoferrin supplementation for prevention of necrotizing enterocolitis in very-low-birth-weight neonates: a randomized clinical trial.

IMPORTANCE: NEC is a common and severe complication in premature neonates, particularly those with very-low-birth-weight (VLBW, <1500 g at birth). Probiotics including lactobacillus rhamnosus GG (LGG) proved effective in preventing NEC in preterm infants in several RCTs. OBJECTIVE: Lactoferrin, a mammalian milk glycoprotein involved in innate immune host defences, can reduce the incidence of NEC in animal models, and its action is enhanced by LGG. We tried to assess whether bovine lactoferrin (BLF), alone or with the probiotic LGG, has a similar effect in human infants, something that has not yet been studied. DESIGN: An international, multicenter, randomized, double-blind, placebo-controlled trial conducted from October 1st, 2007 through July 31st, 2010. SETTING: Thirteen Italian and New Zealand tertiary neonatal intensive care units. PARTICIPANTS: 743 VLBW neonates were assessed until discharge for development of NEC. INTERVENTION: Infants were randomly assigned to receive orally either BLF (100 mg/day) alone (group LF; n = 247) or with LGG (at 6×10(9) CFU/day; group BLF + LGG; n = 238), or placebo (Control group; n = 258) from birth until day 30 of life (45 for neonates <1000 g at birth). MAIN OUTCOME MEASURES: ≥ stage 2 NEC; death-and/or-≥ stage 2 NEC prior to discharge. RESULTS: Demographics, clinical and management characteristics of the 3 groups were similar, including type of feeding and maternal milk intakes. NEC incidence was significantly lower in groups BLF and BLF + LGG [5/247 (2.0%)] and 0/238 (0%), respectively] than in controls [14/258 (5.4%)] (RR = 0.37; 95% CI: 0.136-1.005; p = 0.055 for BLF vs. control; RR = 0.00; p < 0.001 for BLF + LGG vs. control). The incidence of death-and/or-NEC was significantly lower in both treatment groups (4.0% and 3.8% in BLF and BLF + LGG vs. 10.1% in control; RR = 0.39; 95% CI: 0.19-0.80; p = 0.008. RR = 0.37; 95% CI: 0.18-0.77; p = 0.006, respectively). No adverse effects or intolerances to treatment occurred. CONCLUSIONS AND RELEVANCE: Compared with placebo, BLF supplementation alone or in combination with LGG reduced the incidence of ≥ stage 2 NEC and of death-and/or ≥ stage 2 NEC in VLBW neonates. BLF might be a promising strategy to prevent NEC in NICU settings. Further data on larger sample sizes are warranted before BLF can be widespreadly used in clinical settings. TRIAL REGISTRATION: ISRCTN53107700-http://www.controlled-_trials.com/ISRCTN53107700.

Human milk feeding prevents retinopathy of prematurity (ROP) in preterm VLBW neonates.

BACKGROUND: Retinopathy of prematurity (ROP) is a multifactorial disease, but little is known about its relationships with neonatal nutritional policies. Human, maternal milk is the best possible nutritional option for all premature infants, including those at high risk for severe complications of prematurity, such as ROP. OBJECTIVE: This is a secondary analysis of data collected during two multicenter RCTs performed consecutively (years 2004 through 2008) by a network of eleven tertiary NICUs in Italy. The two trials aimed at assessing effectiveness of fluconazole prophylaxis (Manzoni et al., N Engl J Med 2007 Jun 14;356(24):2483-95), and of bovine lactoferrin supplementation (Manzoni et al., JAMA 2009 Oct 7;302(13):1421-8), in prevention of invasive fungal infection, and of late-onset sepsis in VLBW infants, respectively. We tested the hypothesis that exclusive feeding with fresh maternal milk may prevent ROP of any stage - as defined by the ETROP study - in VLBW neonates, compared to formula feeding. METHODS: We analyzed the database from both trials. Systematic screening for detection of ROP was part of the protocol of both studies. The definition of threshold ROP was as defined by the ETROP study. Univariate analysis was performed to look for significant associations between ROP and several possible associated factors, and among them, the type of milk feeding (maternal milk or formula for preterms). When an association was indicated by p < 0.05, multiple logistic regression was used to determine the factors significantly associated with ROP. RESULTS: In both trials combined, 314 infants received exclusively human maternal milk (group A), and 184 a preterm formula because their mothers were not expected to breastfeed. The clinical, demographical and management characteristics of the neonates did not differ between the two groups, particularly related to the presence of the known risk factors for ROP. Overall, ROP incidence (any stage) was significantly lower in infants fed maternal milk (11 of 314; 3.5%) as compared to formula-fed neonates (29 of 184; 15.8%) (RR 0.14; 95% CI 0.12-0.62; p = 0.004). The same occurred for threshold ROP (1.3% vs. 12.3%, respectively; RR 0.19; 95% CI 0.05-0.69; p = 0.009). At multivariate logistic regression controlling for potentially confounding factors that were significantly associated to ROP (any stage) at univariate analysis (birth weight, gestational age, days on supplemental oxygen, systemic fungal infection, outborn, hyperglycaemia), type of milk feeding retained significance, human maternal milk being protective with p = 0.01. CONCLUSIONS: Exclusive human, maternal milk feeding since birth may prevent ROP of any stage in VLBW infants in the NICU.

Sustained lung inflation in the delivery room in preterm infants at high risk of respiratory distress syndrome (SLI STUDY): study protocol for a randomized controlled trial.

BACKGROUND: Some studies have suggested that the early sustained lung inflation (SLI) procedure is effective in decreasing the need for mechanical ventilation (MV) and improving respiratory outcome in preterm infants. We planned the present randomized controlled trial to confirm or refute these findings. METHODS/DESIGN: In this study, 276 infants born at 25(+0) to 28(+6) weeks' gestation at high risk of respiratory distress syndrome (RDS) will be randomized to receive the SLI maneuver (25 cmH2O for 15 seconds) followed by nasal continuous positive airway pressure (NCPAP) or NCPAP alone in the delivery room. SLI and NCPAP will be delivered using a neonatal mask and a T-piece ventilator.The primary endpoint is the need for MV in the first 72 hours of life. The secondary endpoints include the need and duration of respiratory support (NCPAP, MV and surfactant), and the occurrence of bronchopulmonary dysplasia (BPD). TRIAL REGISTRATION NUMBER: NCT01440868.

MRI evidence: acute mountain sickness is not associated with cerebral edema formation during simulated high altitude.

Acute mountain sickness (AMS) is a common condition among non-acclimatized individuals ascending to high altitude. However, the underlying mechanisms causing the symptoms of AMS are still unknown. It has been suggested that AMS is a mild form of high-altitude cerebral edema both sharing a common pathophysiological mechanism. We hypothesized that brain swelling and consequently AMS development is more pronounced when subjects exercise in hypoxia compared to resting conditions. Twenty males were studied before and after an eight hour passive (PHE) and active (plus exercise) hypoxic exposure (AHE) (F(i)O(2) = 11.0%, P(i)O(2)∼80 mmHg). Cerebral edema formation was investigated with a 1.5 Tesla magnetic resonance scanner and analyzed by voxel based morphometry (VBM), AMS was assessed using the Lake Louise Score. During PHE and AHE AMS was diagnosed in 50% and 70% of participants, respectively (p>0.05). While PHE slightly increased gray and white matter volume and the apparent diffusion coefficient, these changes were clearly more pronounced during AHE but were unrelated to AMS. In conclusion, our findings indicate that rest and especially exercise in normobaric hypoxia are associated with accumulation of water in the extracellular space, however independent of AMS development. Thus, it is suggested that AMS and HACE do not share a common pathophysiological mechanism.

Bovine lactoferrin prevents invasive fungal infections in very low birth weight infants: a randomized controlled trial.

BACKGROUND: Lactoferrin is a mammalian milk glycoprotein involved in innate immunity. Recent data show that bovine lactoferrin (bLF) prevents late-onset sepsis in preterm very low birth weight (VLBW) neonates. METHODS: This is a secondary analysis of data from a multicenter randomized controlled trial where preterm VLBW neonates randomly received bLF (100 mg/day; group A1), bLF + Lactobacillus rhamnosus GG (10(6) colony-forming units per day; group A2), or placebo (group B) for 6 weeks. Here we analyze the incidence rates of fungal colonization, invasive fungal infection (IFI), and rate of progression from colonization to infection in all groups. RESULTS: This study included 472 neonates whose clinical, nutritional, and demographical characteristics were similar. Overall, the incidence of fungal colonization was comparable (17.6%, 16.6%, and 18.5% in A1, A2, and B, respectively; P = .89 [A1] and .77 [A2]). In contrast, IFIs were significantly decreased in A1 and A2 (0.7% and 2.0%, respectively) compared with B (7.7%; P = .002 [A1] and .02 [A2]), and this was significantly true both in <1000 g (0.9% [A1] and 5.6% [A2], vs 15.0%) and in 1001 to 1500 g infants (0% and 0% vs 3.7%). The progression rate colonization-infection was significantly lower in the bLF groups: 3.7% (A1) and 12% (A2), vs 41.9%; P < .001 (A1) and P = .02 (A2). No IFI-attributable deaths occurred in the treatment groups, versus 2 in placebo. No adverse effects or intolerances occurred. CONCLUSIONS: Prophylactic oral administration of bLF reduces the incidence of IFI in preterm VLBW neonates. No effect is seen on colonization. The protective effect on IFI is likely due to limitation of ability of fungal colonies to progress toward invasion and systemic disease in colonized infants.

Lutein and zeaxanthin supplementation in preterm infants to prevent retinopathy of prematurity: a randomized controlled study.

OBJECTIVES: Lutein and its isomer zeaxanthin (L/Z) function in the eye as antioxidant agents and blue-light filters. Our aim was to evaluate whether their administration could help decrease the occurrence of retinopathy of prematurity (ROP) in preterm infants. METHODS: Infants with gestational age ≤32 weeks were randomly assigned to receive a daily dose of L/Z (0.14 + 0.006 mg) or placebo until discharge. RESULTS: ROP occurrence was similar in the L/Z (11/58; 19%) and placebo (15/56; 27%) groups, as the occurrence of ROP at each stage and the need of eye surgery. CONCLUSION: L/Z supplementation was ineffective in preventing ROP in preterm infants and did not affect the outcome at discharge of our patients.

Reconciling ethical and legal aspects in neonatal intensive care.

During the last two decades there has been an enormous development in treatment possibilities for the extremely premature infants and the Neonatologists have to face in their daily practice many decisional problems and ethical, moral and legal dilemmas. These concern decisions to initiate or withhold treatment directly at birth, decision to withdrawn treatment with the possible consequence that the child will die. The debate between "sanctity" and "quality" of life, aggressive treatment in relation to discrimination toward the disabled, the principle of "beneficence" and the question of "proportionality" of treatment, the concept of the newborn's "best interest" are the ethical issues discussed. According to our opinion, ethical questions should not be regulated by law and the legal system should not interfere in the relationship patient - physician. Today more than ever, every neonatologist needs to become familiar with basic ethical concepts and the legal aspects in neonatal intensive care.

Similar qualitative and quantitative changes of mitochondrial respiration following strength and endurance training in normoxia and hypoxia in sedentary humans.

Endurance and strength training are established as distinct exercise modalities, increasing either mitochondrial density or myofibrillar units. Recent research, however, suggests that mitochondrial biogenesis is stimulated by both training modalities. To test the training "specificity" hypothesis, mitochondrial respiration was studied in permeabilized muscle fibers from 25 sedentary adults after endurance (ET) or strength training (ST) in normoxia or hypoxia [fraction of inspired oxygen (Fi(O(2))) = 21% or 13.5%]. Biopsies were taken from the musculus vastus lateralis, and cycle-ergometric incremental maximum oxygen uptake (VO(2max)) exercise tests were performed under normoxia, before and after the 10-wk training program. The main finding was a significant increase (P < 0.05) of fatty acid oxidation capacity per muscle mass, after endurance and strength training under normoxia [2.6- and 2.4-fold for endurance training normoxia group (ET(N)) and strength training normoxia group (ST(N)); n = 8 and 3] and hypoxia [2.0-fold for the endurance training hypoxia group (ET(H)) and strength training hypoxia group (ST(H)); n = 7 and 7], and higher coupling control of oxidative phosphorylation. The enhanced lipid oxidative phosphorylation (OXPHOS) capacity was mainly (87%) due to qualitative mitochondrial changes increasing the relative capacity for fatty acid oxidation (P < 0.01). Mitochondrial tissue-density contributed to a smaller extent (13%), reflected by the gain in muscle mass-specific respiratory capacity with a physiological substrate cocktail (glutamate, malate, succinate, and octanoylcarnitine). No significant increase was observed in mitochondrial DNA (mtDNA) content. Physiological OXPHOS capacity increased significantly in ET(N) (P < 0.01), with the same trend in ET(H) and ST(H) (P < 0.1). The limitation of flux by the phosphorylation system was diminished after training. Importantly, key mitochondrial adaptations were similar after endurance and strength training, regardless of normoxic or hypoxic exercise. The transition from a sedentary to an active lifestyle induced muscular changes of mitochondrial quality representative of mitochondrial health.

[Conversion from MCI (Mild Cognitive Impairment) to Alzheimer's disease: diagnostic options and predictors]. / Konversion von MCI (Mild Cognitive Impairment) zur Alzheimer-Demenz: Diagnostische Möglichkeiten und Prädikatoren.

OBJECTIVE: The first part of this article deals with the concept of Mild Cognitive Impairment and its role in the pathogenesis of dementia. In the second part neuroradiologic diagnostic methods which can potentially help to predict the conversion of MCI to Alzheimer s disease (DAT) are discussed. METHODS: We reviewed in PubMed published literature for reports which investigated diagnosis and progress of patients with MCI and DAT. RESULTS: Patients with MCI older than 65 years have a risk of 10-15%/year to develop dementia in comparison to the healthy population with a risk of 2%/year. Neuroradiologic methods such as MR-spectroscopy, FDGPET, DWI and VBM are able to differentiate patients who will convert to DAT from patients who remain stable. Structural changes can be detected prior to clinically measurable cognitive deficits. CONCLUSION: The neuroradiologic examination using MR- Spectroscopy, VBM, DWI or FDG-PET show early structural and functional changes which can predict a conversion from MCI to DAT.

Neonatal neuroimaging: going beyond the pictures.

The cerebral ultrasound has been used many years for the diagnosis of brain lesions in term and preterm newborns. Major improvements were obtained by the combination of different imaging modalities such as Magnetic Resonance Imaging with the Diffusion Weighted Imaging (DWI) and the new quantitative Diffusion Tensor Imaging (DTI). The clinical use of MRI has been validated over some years especially to depict the perinatal asphyxia lesions in term newborns, but its use in order to diagnose the typical diseases of preterm babies is very recent and useful in identifying a marker able to predict neurological outcome. The imaging correlates for motor impairment are well recognized (periventricular white matter cavitations), but no any imaging correlate for cognitive impairment and neurobehavioral disorders. While DWI has been used in term newborns to identify the ischemic areas with restricted diffusion, it may be also used to characterize brain development in preterm infants with the Apparent Diffusion Coefficient (ADC) and may allow us to detect abnormalities responsible for the non-motor impairments. Recent datas showed that in infants without focal lesions higher ADC values in WM were associated with poorer neurodevelopmental assessment at 2 years. The DTI also allows to detect the Fractional Anisotropy (FA) that measures the microstructure. DTI can also be used to map the WM tracts in the immature brain and may be applied to understand the normal development or the response of the brain to injury. Some WM regions in the preterm brain have a lower FA suggesting that widespread WM abnormalities are present in preterms even in the absence of focal lesions. The complexity of the developing brain can be explained by the new tractography that can assess the connectivity of different WM regions and the association between structure and function, such as optic radiations microstructure and visual assessment score. Technological advances in neonatal brain imaging have made a major contribution to understand the neurobehavioral disorders of the developing brain that have the origin in the early structural cerebral organization and maturation.

Bovine lactoferrin supplementation for prevention of late-onset sepsis in very low-birth-weight neonates: a randomized trial.

CONTEXT: Sepsis is a common and severe complication in premature neonates, particularly those with very low birth weight (VLBW) (<1500 g). Whether lactoferrin, a mammalian milk glycoprotein involved in innate immune host defenses, can reduce the incidence of sepsis is unknown. In animal models, the probiotic Lactobacillus rhamnosus GG (LGG) enhances the activity of lactoferrin but has not been studied in human infants. OBJECTIVE: To establish whether bovine lactoferrin (BLF), alone or in combination with LGG, reduces the incidence of late-onset sepsis in VLBW neonates. DESIGN, SETTING, AND PATIENTS: Prospective, multicenter, double-blind, placebo-controlled, randomized trial conducted in 11 Italian tertiary neonatal intensive care units. Patients were 472 VLBW infants enrolled from October 1, 2007, through July 31, 2008, and assessed until discharge for development of sepsis. INTERVENTION: Infants were randomly assigned to receive orally administered BLF (100 mg/d) alone (n = 153), BLF plus LGG (6 x 10(9) colony-forming units/d) (n = 151), or placebo (n = 168) from birth until day 30 of life (day 45 for neonates <1000 g at birth). MAIN OUTCOME MEASURE: First episode of late-onset sepsis, ie, sepsis occurring more than 72 hours after birth with isolation of any pathogen from blood or from peritoneal or cerebrospinal fluid. RESULTS: Demographic, clinical, and management characteristics of the 3 groups were similar, including type of feeding and intake of maternal milk. Incidence of late-onset sepsis was significantly lower in the BLF and BLF plus LGG groups (9/153 [5.9%] and 7/151 [4.6%], respectively) than in the control group receiving placebo (29/168 [17.3%]) (risk ratio, 0.34; 95% confidence interval, 0.17-0.70; P = .002 for BLF vs control and risk ratio, 0.27; 95% confidence interval, 0.12-0.60; P < .001 for BLF plus LGG vs control). The decrease occurred for both bacterial and fungal sepsis. No adverse effects or intolerances to treatment occurred. CONCLUSION: Compared with placebo, BLF supplementation alone or in combination with LGG reduced the incidence of a first episode of late-onset sepsis in VLBW neonates. TRIAL REGISTRATION: isrctn.org Identifier: ISRCTN53107700.

Phosphocreatine kinetics in the calf muscle of patients with bilateral symptomatic peripheral arterial disease during exhaustive incremental exercise.

PURPOSE: To investigate the relationship between the atherosclerotic lesion load determined on magnetic resonance angiography (MRA) and phosphocreatine (PCr) kinetics during incremental, exhaustive calf exercise in patients with bilateral, symptomatic peripheral arterial disease (PAD). PROCEDURES: Using a 1.5 Tesla MR scanner, 26 patients with bilateral symptomatic PAD and 24 healthy male controls underwent serial phosphorus-31 MR spectroscopy (31P MRS) during incremental exercise at 2, 3, 4, and 5 Watts. For each increment and recovery, PCr time constants, amplitudes of PCr changes and pH values were calculated from the MR spectra. In patients, the run-off resistance (ROR) was determined on MRA. RESULTS: The patients exhibited significantly (p

High-energy phosphate metabolism in the calf muscle of healthy humans during incremental calf exercise with and without moderate cuff stenosis.

It is known that the relevance of a peripheral stenosis for muscle function increases with exercise. Our intention was to investigate the impact of a moderate cuff stenosis (CS) at 120 mmHg of the superficial femoral artery on high-energy phosphate (HEP) metabolism during isotonic, incremental calf exercise. Serial phosphorus 31 magnetic resonance spectroscopy (31P MRS) and velocity-encoded phase-contrast MR imaging (VEPC MRI) were carried out in each leg of ten healthy male volunteers. Each leg underwent four increments of calf exercise (2, 3, 4 and 5 W) followed by recovery during separate exercise sessions with and without a CS at 120 mmHg. The serial 31P MRS measurements had a time resolution of 10 s. VEPC MRI was performed at the end of each increment during separate sessions. During all increments, we detected significant differences (P < 0.05) in the phosphocreatine (PCr) time constants and the amount of PCr hydrolysis between the sessions without and with CS. Regarding the time courses of the PCr, inorganic phosphate (Pi) and pH level, we observed significant differences (P < 0.002) during exercise and recovery. During both conditions, the end-increment PCr levels as well as blood flow correlated significantly with the mechanical power. The PCr time constants during exercise significantly correlated with the intramuscular pH, but not with blood flow or mechanical power. However, the PCr recovery time constants correlated significantly with blood flow and end-exercise pH. Our study shows that reduction of blood flow due to a peripheral stenosis results in a prolongation of PCr time constants, decreased PCr and pH level as well as increased Pi level during exercise. We believe that 31P MRS during incremental exercise might provide additional information for assessing the relevance of a peripheral stenosis and its impact on muscle function.

High-energy phosphate metabolism during incremental calf exercise in patients with unilaterally symptomatic peripheral arterial disease measured by phosphor 31 magnetic resonance spectroscopy.

BACKGROUND: The treadmill exercise test is the most important examination of the functional ability of patients with intermittent claudication or leg pain during exercise, but it does not provide any metabolic information in the calf muscle. The purpose of this study was to investigate the high-energy metabolism in the calf muscle during incremental progressive plantar flexion exercise of a selected peripheral arterial disease (PAD) patient group. METHODS: Using a 1.5-T whole-body magnetic resonance scanner, 17 male patients with PAD who had 1 symptomatic and 1 asymptomatic leg and 9 healthy male controls underwent serial phosphor 31 (31P) magnetic resonance spectroscopy during incremental exercise at 2, 3, 4, and 5 W. Furthermore, magnetic resonance angiography was performed, and the ankle-brachial pressure index was determined in the patient group. The runoff resistance (ROR) was separately assessed in each patient's leg. RESULTS: The symptomatic legs exhibited significantly increased phosphocreatine (PCr) time constants during the first three workload increments (2-4 W) and the recovery phase compared with the asymptomatic legs and the normal controls. Only two symptomatic legs reached the last increment at 5 W. Compared with the normal controls, the asymptomatic legs showed significantly increased PCr time constants only at 5 W. In the patient group, we detected significant correlations between the PCr time constants and the ROR, as well as the ankle-brachial pressure index. Moreover, the symptomatic legs presented significantly lower PCr levels and pH values at the end of exercise compared with the asymptomatic and control legs. CONCLUSIONS: Our study shows that muscle function in PAD patients can be objectively quantified with the help of 31P magnetic resonance spectroscopy and correlates significantly with hemodynamic parameters such as ROR and ankle-brachial pressure index. Consequently, 31P magnetic resonance spectroscopy seems to be a useful method to monitor the muscle function of PAD patients for evaluation of established therapies or new therapeutic strategies during research trials.

Altered thyroid and adrenal function in children born at term and preterm, small for gestational age.

Intrauterine growth retardation may permanently influence the endocrine system by affecting its programming during development. The aim of this study was to evaluate thyroid and adrenal function together with insulin sensitivity in a group of children born small for gestational age (SGA). Forty SGA children (mean age, 6.7 +/- 1.7 yr) and 35 children born appropriate for gestational age (mean age, 6.5 +/- 2.2 yr) were selected for the study. TSH, free T4, free T3 (fT3), rT3, antithyroid antibodies, cortisol, and dehydroepiandrosterone sulfate (DHEAS) were assessed. Insulin sensitivity was evaluated with the quantitative insulin sensitivity check index (QUICKI). A thyroid ultrasound was also performed in the SGA children. We found that TSH was significantly higher in SGA than in children born appropriate for gestational age [2.9 +/- 1.1 vs. 1.7 +/- 0.7 microU/ml (mIU/liter); P < 0.001]; furthermore, eight SGA children (20%), seven born preterm and one at term, had TSH levels above the upper limit of normality. fT3 was also higher in SGA children (4.2 +/- 0.4 vs. 3.6 +/- 0.6 pg/ml; 6.4 +/- 0.6 vs. 5.5 +/- 0.9 pmol/liter; P < 0.0001), whereas no difference was found for free T4, rT3, and the fT3/rT3 ratio. Urinary iodine was normal, and antithyroid antibodies were absent. Thyroid ultrasound showed a normal echographic pattern with a normal volume in SGA children. Serum cortisol was similar in both groups, whereas DHEAS was significantly lower in SGA subjects (43 +/- 18 vs. 65 +/- 50 microg/dl; 1.1 +/- 0.4 vs. 1.7 +/- 1.3 micromol/liter; P < 0.05). There was no difference in insulin sensitivity between the two groups. Birth length and birth weight were the main determinants of TSH and DHEAS serum levels, respectively. In conclusion, functional thyroid and adrenal changes have been found in children who suffered from intrauterine growth retardation. A larger survey with an appropriate follow-up is, however, required to confirm these findings and to assess their natural evolution.