Nutrient intakes of adolescents with phenylketonuria and infants and children with maple syrup urine disease on semisynthetic diets

Adequacy of nutrient intakes of adolescents with and without phenylketonuria (PKU) and infants and children with and without maple syrup urine disease (MSUD) were assessed using 3-day diet records sorted by disease and by age of the subject. Mean intakes of all nutrients were greater than two-thirds of the Recommended Dietary Allowances (RDA) or Estimated Safe and Adequate Daily Dietary Intakes (ESADDI) for all adolescents studied, with the exception of selenium (Se) in PKU adolescents, which averaged 27.8 micrograms. For adolescents with PKU, > 50% of the RDA or ESADDI for all nutrients was provided by elemental or modified protein hydrolysate medical foods, except for vitamin A in children aged 11-15 years and Se in children 11-18 years. Mean nutrient intakes of all infants and children were greater than two-thirds of the RDA or ESADDI for all nutrients except Se in MSUD children aged 1-11 years, where intakes ranged from 6.4 to 13.2 micrograms (21-66% of the RDA). The medical foods provided for most of the RDA and ESADDI recommendations, with the exception of Se in MSUD children.     

Homozygous parent affected sib pair method for detecting disease predisposing variants: application to insulin dependent diabetes mellitus

For complex genetic diseases involving incomplete penetrance, genetic heterogeneity, and multiple disease genes, it is often difficult to determine the molecular variant(s) responsible for the disease pathogenesis. Linkage and association studies may help identify genetic regions and molecular variants suspected of being directly responsible for disease predisposition or protection, but, especially for complex diseases, they are less useful for determining when a predisposing molecular variant has been identified. In this paper, we expand upon the simple concept that if a genetic factor predisposing to disease has been fully identified, then a parent homozygous for this factor should transmit either of his/her copies at random to any affected children. Closely linked markers are used to determine identity by descent values in affected sib pairs from a parent homozygous for a putative disease predisposing factor. The expected deviation of haplotype sharing from 50%, when not all haplotypes carrying this factor are in fact equally predisposing, has been algebraically determined for a single locus general disease model. Equations to determine expected sharing for multiple disease alleles or multiple disease locus models have been formulated. The recessive case is in practice limiting and therefore can be used to estimate the maximum proportion of putative susceptibility haplotypes which are in fact predisposing to disease when the mode of inheritance of a disease is unknown. This method has been applied to 27 DR3/DR3 parents and 50 DR4/DR4 parents who have at least 2 children affected with insulin dependent diabetes mellitus (IDDM). The transmission of both DR3 and DR4 haplotypes is statistically different from 50% (P < 0.05 and P < 0.001, respectively). An upper estimate for the proportion of DR3 haplotypes associated with a high IDDM susceptibility is 49%, and for DR4 haplotypes 38%. Our results show that the joint presence of non-Asp at DQ beta position 57 and Arg at DQ alpha position 52, which has been proposed as a strong IDDM predisposing factor, is insufficient to explain the HLA component of IDDM predisposition.     

Cigarette smoking and submaximal exercise test duration in a biracial population of young adults: the CARDIA study

Symptom-limited, graded exercise treadmill testing was performed by 4,968 white and black adults, ages 18-30 yr, during the baseline examination for the Coronary Artery Risk Development in Young Adults (CARDIA) study. Compared with nonsmokers, the mean exercise test duration of smokers was 29-64 s shorter depending on race/gender group (all P < 0.001), but mean duration to heart rate 130 (beats.min-1) ranged from 20-50 s longer (P < 0.05). In each race/gender group, test duration to heart rates up to 150 was 15-35 s longer (P < 0.05) in smokers than in nonsmokers after adjustment for age, sum of skinfolds, hemoglobin, and physical activity score. The mean maximum heart rate was lower in smokers than in nonsmokers (difference ranging from 6.7 beats.min-1 in white men to 11.2 beats.min-1 lower in black women, P < 0.001), although maximum rating of perceived exertion was nearly identical in smokers and nonsmokers. Chronic smoking appears to blunt the heart rate response to exercise, so that exercise duration to submaximal heart rates is increased even though maximal performance is impaired. This may result from downloading of beta-receptors caused by smoking. Smoking status should be considered in the evaluation of physical fitness data utilizing submaximal test protocols, or else the fitness of smokers relative to nonsmokers is likely to be overestimated.     

Lysosomal enzyme and inhibitor levels in the human trabecular meshwork

PURPOSE: To examine in the human trabecular meshwork lysosomal enzymes and one inhibitor of serine proteases that actively participate in the degradation of macromolecules into low molecular weight constituents. METHODS: Using an avidin-biotin-peroxidase technique, lysosomal proteases and alpha 1-proteinase inhibitor were examined in the trabecular meshwork of 23 human eyes with donor ages ranging from 2 to 90 years. These eyes were categorized into three age groups (< or = 20, 21 to 49, and > or = 50 years). Histochemical staining for lysosomal hydrolases was also performed on frozen sections of 20 human eyes. The staining was analyzed by an image analyzer and the levels of lysosomal proteases were further measured by biochemical assays. RESULTS: The trabecular meshwork from all the eyes stained intensely against antibodies to cathepsins B and G and alpha 1-proteinase inhibitor. The staining for elastase was weaker but evident. Image analyses revealed that the staining intensity for each protease or inhibitor was similar in all age groups. The staining in the uveal meshwork appeared to be the strongest among all the trabecular meshwork regions. Biochemical assays of tissue extracts confirmed that the enzyme and inhibitor levels were comparable among the three donor age groups. Activities of two lysosomal hydrolases, acid phosphatase and acid esterase, were also found in trabecular meshwork cells of 20 eyes. No apparent difference in enzyme activities was found with increasing age, and variation related to region was not observed. CONCLUSIONS: This study demonstrated the age-independent distribution of a variety of lysosomal enzymes and a protease inhibitor in the human trabecular meshwork. The presence of these proteins suggests a possible role in the metabolic operation of the trabecular meshwork.     

The development of adaptive body reactions after intensive physical loading]

The dependence between the activity parameters of muscarine antagonists in the prevention of haloperidol catalepsy in rats and those in tests characterizing the interaction of ligands and various subtypes of m-cholinoceptors was studied. It was established by constructing the mathematical dependence that blockade of m1-cholinoceptors increases, while that of m2-cholinoceptors reduces the antiparkinsonian activity of the drugs. The activity of the muscarine antagonist pentiphan in the prevention of haloperidol-induced catalepsy in rats exceeds the activity of such traditional antiparkinsonian drugs as cyclodol and amedin.     

Tissue fixation security in transosseous rotator cuff repairs: a mechanical comparison of simple versus mattress sutures

The primary purpose of this investigation was to compare tissue fixation security by simple sutures versus mattress sutures in transosseous rotator cuff repair. These two repair techniques were each performed in 17 human cadaver shoulders, with two bone tunnels being used for the repair by two simple sutures and two other bone tunnels being used for the repair by one mattress suture. The repairs were loaded to failure in a servohydraulic materials test system. Rotator cuff repair by simple sutures was found to be significantly stronger than repair by mattress sutures (P = .0007). The average ultimate load to failure for the simple suture construct (189.62 N) was 39.72% greater than that for the mattress suture construct (135.71 N). Most of the failures occurred by suture breakage at the knot. Load-sharing by multiple suture tails and multiple knots in the simple suture configuration likely contributed to its superior strength characteristics compared with the mattress suture configuration.     

An analysis of pH tolerance and substrate preference of isolated skeletal muscle mitochondria from Bufo marinus and Rana catesbeiana

1. The effects of varying pH and substrate on isolated skeletal muscle mitochondria from Bufo marinus and Rana catesbeiana were investigated. 2. For both species, VO2 max significantly decreased at all pH < 7.3 (P < 0.05), while maximum values were observed at a pH range of 7.3-7.6 with B. marinus maintaining a greater VO2 max than R. catesbeiana. 3. Respiratory control values (RCR) decreased significantly at all pH < 6.9 for both species (P < 0.05). 4. Isolated mitochondria from both species were maintained at pH = 7.2 and O2 consumption measured under five separate substrate conditions. 5. A rank preference was established based upon state 3 and RCR values. 6. Substrate preference was identical for both species and interspecific comparisons revealed differences in state 3 respiration and coupling.     

Dissecting cAMP binding domain A in the RIalpha subunit of cAMP-dependent protein kinase. Distinct subsites for recognition of cAMP and the catalytic subunit

The two gene-duplicated cAMP binding domains in the regulatory subunits of cAMP dependent protein kinase are each comprised of an A helix, an eight-stranded beta-barrel, and a B and C helix (1). The A domain is required for high affinity binding to C, while the B domain regulates access to the A domain. Using a combination of a yeast two-hybrid screen coupled with deletion analysis, cAMP binding domain A of RI was dissected into two structurally and functionally distinct subsites, one that binds cAMP and another that binds the C subunit. The minimum stable subdomain required for binding to C in the 1-3 micromolar range is composed of residues 94-169, while residues 236-244, mapped to the C helix of cAMP binding domain A, were defined as a second surface necessary for high affinity (5-10 nanomolar) binding to C. This portion of the C helix, due to its position directly between the two subsites, serves as a molecular switch for either a cAMP-bound conformation or a C-bound conformation and can thus modulate interactions of cAMP binding domain A with cAMP, with C, and with cAMP binding domain B.