Purpose of the study3-methylhistidine (3-MH) acts as an in vivo label of the rate of myofibrillar protein breakdown.The aim of this study was to evaluate 3-MH measurement in spot urine as a simple screening method for muscle protein degradation in HIV-infected persons compared to creatine kinase (CK) measurement in blood. MethodsWe prospectively measured serum creatinine (mg/dl) and serum CK (U/L) and 3-MH (μmol/L) in spot urine from 162 HIV-positive subjects at each visit.3-MH was determined by HPLC after derivatization with fluorescamine.

Using human (SK-MEL 23, SK-MEL 24 and G361) and murine (B16) melanoma cell lines, the coregulatory potential of the uptake of the positron emission tomography (PET) tracer, [Fluorine-18] 2-fluoro-2-deoxy-D-glucose (F-18 FDG) has been investigated in relationship to tumor characteristics. Comparative studies among the four melanoma cell lines demonstrated that the lowest FDG uptake in SK-MEL 24 corresponded strongly to the data for DT (population doubling time) and MTT (tetrazolium salt) cell viability as well as hexokinase (HK) activity, but was not related to the glucose transporter 1 (GLUT 1) expression level. Furthermore, the FDG uptake in each melanoma cell line measured by cell cycle kinetics was significantly positively correlated to both the proliferation index (PI=S/G2M phase fractions) and the cell viability, though with one exception relating to the PI of the lowest FDG uptake cell line, SK-MEL 24. No positive correlation was found between the expression of GLUT 1 and FDG uptake in any individual cell line. However, the HK activities in SK-MEL 23 and 24 showed considerable positive relationships with FDG uptake. Our present study suggests that both the proliferation rate and the cell viability of melanoma cells may be key factors for FDG uptake and that HK activity, rather than GLUT 1 expression, seems to be a major factor.

Silicon is an essential nutrient of fundamental importance to human biology. It has been shown that silicon is required for bone, cartilage, and connective tissue formation. However, the assessment of silicon concentration is difficult as reference values are lacking. The aim of the present study was to establish reference values for apparently healthy individuals. Silicon concentrations were determined in serum of 1325 healthy subjects 18–91 years of age using atomic absorption spectrometry. Medians for serum silicon concentrations showed a statistically significant age and sex dependency. In men 18–59 years of age the median was 9.5μmol/L and decreased to 8.5μmol/L at 60–74 years of age. In women there was an increase in the median from age 18–29 years (10.00μmol/L) to 30–44 years (11.10μmol/L) followed by a decrease in the age group of 45–59 years (9.23μmol/L). In subjects aged over 74 years the median serum silicon values were 7.70μmol/L for men and 8.00μmol/L for women. The most important findings in this study are the decrease of silicon and the course of the silicon concentrations with age, especially in women. The present study is an important prerequisite for studies that aim to identify the health effects and medical implications of silicon.

BACKGROUND:Some of the genetic variants of hemoglobin (Hb) and their chemically modified species are known to affect the measurement of Hb A(1c). The purpose of this study was to characterize Hb species in the blood sample of a 74-year-old German male with an exceptionally low Hb A(1c) value.METHODS:Hemolysates from the propositus and a healthy individual were analyzed by electrophoresis, cation-exchange HPLC, boronate affinity chromatography, and electrospray ionization-mass spectrometry (ESMS). Genomic DNA was amplified by PCR, and the sequencing was performed on an ABI 310 sequencer. Functional properties of Hb were determined by oxygen equilibrium studies and CO recombination kinetics after flash photodissociation. Glycohemoglobin species were synthesized by incubating hemolysates with glucose.RESULTS:A novel, electrophoretically silent beta chain, beta5(A2)Pro-->Ala or Hb Görwihl, was detected by cation-exchange HPLC. It accounted for approximately 44% of the total Hb and had functional properties similar to those of normal Hb A and a mild degree of heat instability. During incubation with glucose, glycation of the beta chains (assessed by ESMS) in the hemolysate of a healthy volunteer was twice as fast as in hemolysate from the propositus.CONCLUSIONS:The substitution beta5(A2)Pro-->Ala seems to affect neither the functional properties nor the heterotropic interactions of Hb, but slows glycation of the N-terminal valine by an unknown mechanism.

We investigated blood lipids and exercise tolerance (ET) in 78 patients ranging in age from 37 to 93 yrs (65.9 ± 9.3) with documented coronary artery disease (CAD) before and after a 12-week, Phase II, cardiac rehabilitation program. Patients were divided into 3 groups by age: Group I, 37 to 59 yrs; Groups II, 60 to 69 yrs; and Group III, 70 to 79 yrs. An ET test was administered using a motorized treadmill (Bruce protocol) before and after training. Venous blood samples were obtained from a peripheral forearm vein and assayed for cholesterol (T-CHOL), triglycerides (TRIG), low-density lipoprotein (LDL-C), and high-density lipoprotein (HDL-C) by spectrophotometry. Patients exercised 3 times per wk for 50 min (including a 10 min warm-up and 10 min cool-down) at an intensity equal to 70% maximal heart rate. ANOVA revealed significant (P < 0.05) reductions in all subjects for: T-CHOL (216.3 ± 42.8 to 204.1 ± 50.4 mg/dl), TRIG (193.8 ± 50.4 to 170.9 ± 52.6; and T-CHOL/HDL ratio (6.5 ± 1.9 to 5.9 ± 1.8). Although improvements were observed in LDL-C (145.2 ± 38.0 to 132.8 ± 29.5 mg/dl) and HDL-C (35.1 ± 9.9 to 36.3 ± 9.3 mg/dl) they failed to reach statistical significance. Exercise time and intensity increased by 33.3% (5.1 ± 1.9 to 6.8 ± 1.8 min) and 35.3% (5.2 ± 2.0 to 6.9 ± 1.8 METS) respectively for all patients. Posthoc analysis revealed age-related differences in post-test results for T-CHOL, TRIG and the CHOL/HDL ratio. These findings suggest 12 weeks of training provided an adequate stimulus for our patients to display an enhancement in ET and blood lipids. Further, it appears differences exist in the magnitude of change in lipids profiles when patients were stratified by age.