Correlates of cortical bone mass among premenopausal and postmenopausal Japanese women.

Few studies have examined the multifactorial risk factors of bone mass in Asian populations. This cross-sectional study was designed to explore relationships between bone mass and environmental variables, including dietary and life-style factors, in Japanese women living in Japan. A total of 178 Japanese women completed the study: 89 premenopausal, ages 35-40, and 89 postmenopausal, ages 55-60. Midradial bone mineral content (MBMC) and bone mineral content per unit area, referred to as bone density (MBMD), were measured using single-photon absorptiometry. The major results of this investigation were the following: (1) The postmenopausal women differed significantly from the premenopausal women in having lower radial bone parameters, lower mean height, later age of menarche, and higher dietary intakes of carbohydrates, vegetables, and milk with a lower intake of caffeine. (2) Current protein intake was a positive correlate of MBMC in both groups. (3) Intake of vegetables (leafy green, yellow, orange, and white) and current milk intake were positively associated with MBMC in the postmenopausal women. (4) For the premenopausal women, irregular menstrual cycles was a negative correlate of MBMC, and for the postmenopausal women, years of menopause was negatively associated with MBMC and MBMD. Longitudinal studies are needed to establish more conclusively associations among diet, life-style, and reproductive history and bone mass of Japanese women.

Is glutamine a conditionally essential amino acid?

The nonessential amino acid glutamine has recently been the focus of extensive scientific interest because of its importance in cell and tissue cultures and its physiologic role in animals and humans. Glutamine appears to be a unique amino acid, serving as a preferred respiratory fuel for rapidly proliferating cells, such as enterocytes and lymphocytes; a regulator of acid-base balance through the production of urinary ammonia; a carrier of nitrogen between tissues; and an important precursor of nucleic acids, nucleotides, amino sugars, and proteins. Abundant evidence suggests that glutamine may become a "conditionally essential" amino acid in the critically ill. During stress the body's requirements for glutamine appear to exceed the individual's ability to produce sufficient amounts of this amino acid. Provision of supplemental glutamine in specialized enteral or parenteral feeding may enhance nutritional management and augment recovery of the seriously ill while minimizing hospital stay.

Glutamine-antioxidant supplementation increases body cell mass in AIDS patients with weight loss: a randomized, double-blind controlled trial.

Loss of body cell mass, the active functioning tissue of the body, commonly occurs in patients with human immunodeficiency virus (HIV) infection, and the extent of wasting is related to the length of survival. We evaluated the anabolic role of the amino acid L-glutamine (GLN) and antioxidants in a double-blind, placebo-controlled trial in 26 patients with > 5% weight loss since disease onset. Subjects received GLN-antioxidants (40 g/d) in divided doses or glycine (40 g/d) as the placebo for 12 wk. Throughout the study, the subjects were seen weekly by a nutritionist, and body weight, bioelectric impedance assessment, and nutritional counseling were performed. Twenty-one subjects completed the study, and the groups were well matched. The 5 patients excluded from analysis all met a priori exclusion criteria. Over 3 mo, the GLN-antioxidant group gained 2.2 kg in body weight (3.2%), whereas the control group gained 0.3 kg (0.4%, P = 0.04 for difference between groups). The GLN-antioxidant group gained 1.8 kg in body cell mass, whereas the control group gained 0.4 kg (P = 0.007). Intracellular water increased in the GLN-antioxidant group but not in the control group. In conclusion, GLN-antioxidant nutrient supplementation can increase body weight, body cell mass, and intracellular water when compared with placebo supplementation. GLN-antioxidant supplementation provides a highly cost-effective therapy for the rehabilitation of HIV+ patients with weight loss.

The effects of glutamine-supplemented parenteral nutrition in premature infants.

BACKGROUND: Glutamine (GLN) is the primary fuel for rapidly dividing cells, yet it is not a constituent of parenteral nutritional formulas administered to newborns. The aims of this prospective, randomized, double-blind trial were (1) to confirm the safety of glutamine supplementation for premature infants and (2) to examine the effects of glutamine-supplemented parenteral nutrition on length of stay, days on total parenteral nutrition (TPN), days on the ventilator, and other clinical outcomes. METHODS: Premature infants received either standard or glutamine-supplemented TPN and were monitored throughout length of stay for various health and biochemical indices. The group was examined as a whole (n = 44; birth weight range: 530 to 1250 g) and in two weight subgroups, < 800 and > or = 800 g. RESULTS: Serum ammonia, blood urea nitrogen, and glutamate tended to be higher in the GLN groups, but the levels were well within normal limits. In the < 800-g cohort (n = 24), glutamine-supplemented infants required fewer days on TPN (13 vs 21 days, p = .02), had a shorter length of time to full feeds (8 vs 14 days, p = .03), and needed less time on the ventilator (38 vs 47 days, p = .04). There was a tendency toward a shorter length of stay in the NICU (73 vs 90 days, NS). These findings were not observed in the infants > or = 800 g (n = 20). CONCLUSIONS: Glutamine appears to be safe for use in premature infants and seems to be conditionally essential in premature infants with extremely low birth weights. Larger multicenter trials are needed to confirm these observations and further evaluate the efficacy of GLN in these high-risk premature infants.

Diagnosis of adrenal cortical dysfunction by liquid chromatography-tandem mass spectrometry.

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to measure 6 metabolic compounds of the adrenocorticosteroid pathway simultaneously on residual specimens from patients who had previously been previously diagnosed, on the basis of immunoassays, as having congenital adrenal hyperplasia (CAH), 11 beta-hydroxylase deficiency, 21-hydroxylase deficiency, or Addison disease (adrenal insufficiency). Two subjects with normal adrenal function had serum cortisol values of 13.6 and 8.9 micrograms/dL and serum cortisone values of 2.1 and 0.6 microgram/dL, but the rest of the compounds were undetectable. Two patients with 11 beta-hydroxylase deficiency had serum 11 beta-deoxycortisol values of 14.9 and 10.0 micrograms/dL and serum 11-deoxycorticosterone values of 3.9 and 1.0 microgram/dL, but their serum levels of cortisol and cortisone were diminished. A patient with 21-hydroxylase deficiency had a highly increased serum 17-hydroxyprogesterone concentration of 28.5 micrograms/dL (or 28,500 ng/dL, the traditional unit to report this assay) and a serum 21-deoxycortisol concentration of 6.9 ug/dL (this is a pathologic marker of 21-hydroxylase deficiency that is nondetectable in sera of healthy subjects). This patient also had diminished concentrations of serum cortisol and cortisone (0.9 and 0.3 microgram/dL, respectively). At 30 and 60 min after corticotropin (ACTH) stimulation, serum cortisol was the only compound that showed a dramatic increase in the normal subjects; the patient with 21-hydroxylase deficiency showed an increase of serum 17-hydroxyprogesterone level, but no increase of serum cortisol level; the patient with Addison disease showed no increase in the levels of serum cortisol or other compounds. Metyprapone, which blocks 11 beta-hydroxylase activity, increased the serum 11-deoxycorticosteroid levels and decreased the serum cortisol level. This pilot study demonstrates that it is feasible to use LC-MS/MS for the laboratory diagnosis of adrenal cortical dysfunction. The authors envision that LC-MS/MS may soon become an ideal analytical technique for the diagnosis of such endocrine diseases.

Acupuncture for the treatment of obesity: a review of the evidence.

Although acupuncture is being utilized to treat a variety of important health problems, its usefulness in obesity management has not yet been fully evaluated. The aim of this review paper was to survey and critically evaluate the descriptive and controlled trials of acupuncture for enhancing weight loss. The underlying principles of acupoint stimulation are described, with an emphasis on auricular (ear) acupuncture, the method most often chosen for obesity studies. The difficulties of selecting suitable placebo controls are highlighted. To date, most trials have been descriptive in nature, of short duration (< or = 12 weeks), and designed using nonstandard treatment protocols. Despite the unique challenges involved, further careful study of acupuncture's potential usefulness as an adjunct in weight management is recommended. An agenda for future research in this area is provided.

Method for the determination of total homocysteine in plasma and urine by stable isotope dilution and electrospray tandem mass spectrometry.

BACKGROUND: Total homocysteine (tHcy) has emerged as an important independent risk factor for cardiovascular disease. Analytical methods are needed to accommodate the high testing volumes for tHcy and provide rapid turnaround. METHODS: We developed liquid chromatography electrospray tandem mass spectrometry (LC-MS/MS) method based on the analysis of 100 microL of either plasma or urine with homocystine-d(8) (2 nmol) added as internal standard. After sample reduction and deproteinization, the analysis was performed in the multiple reaction monitoring mode in which tHcy and Hcy-d(4) were detected through the transition from the precursor to the product ion (m/z 136 to m/z 90 and m/z 140 to m/z 94, respectively). The retention time of tHcy and Hcy-d(4) was 1.5 min in a 2.5-min analysis. RESULTS: Daily calibrations between 2.5 and 60 micromol/L exhibited consistent linearity and reproducibility. At a plasma concentration of 0.8 micromol/L, the signal-to-noise ratio for tHcy was 17:1. The regression equation for the comparison between our previous HPLC method (y) and the LC-MS/MS method (x) was y = 1.097x - 1.377 (r = 0.975; S(y|x) =1.595 micromol/L; n = 367), and for comparison between a fluorescence polarization immunoassay (Abbott IMx; y) and LC-MS/MS (x) was y = 1.039x + 0.025 (r = 0.969; S(y|x) =1.146 micromol/L; n = 367). Inter- and intraassay CVs were 2.9-5.9% and 3.6-5.3%, respectively, at mean concentrations of 3.9, 22.7, and 52.8 micromol/L. Mean recovery of tHcy was 94.2% (20 micromol/L) and 97.8% (50 micromol/L). CONCLUSIONS: The sensitivity and specificity of tandem mass spectrometry are well suited to perform high-volume analysis of tHcy. Reagents are inexpensive and sample preparation of a batch of 40 specimens is completed in less than 1 h and is amenable to automation.

Online single-step analysis of blood proteins: the transferrin story.

The serum iron transport protein human transferrin (hTf) is a glycoprotein (MW approximately 79.6 kDa) containing two Asn-linked sites of glycosylation. The presence of specific glycoforms of hTf has been used as an indicator of carbohydrate-deficient glycoprotein syndrome (CDGS) or an indicator of alcohol abuse. The exact nature of the glycoforms described in the literature is controversial. In this work we demonstrate that the altered hTf glycoforms have lost one or both complete glycan side chains. Furthermore, we demonstrate using a combination of online immunoaffinity-postconcentration-mass spectrometry in conjunction with a blood spot cartridge that we can determine the relative quantities of the hTf glycoforms using <5 microL blood in under 30 min. This is in contrast to previous methods that used 1 mL and took 4 days. We show that this method can be useful to analyze hTf from CDGS and alcoholic patients.

Rapid determination of transferrin isoforms by immunoaffinity liquid chromatography and electrospray mass spectrometry.

BACKGROUND: Congenital disorders of glycosylation (CDG) are autosomal recessive disorders that produce increased serum carbohydrate-deficient transferrin (CDT) isoforms. Methods to resolve CDT from fully glycosylated transferrin (Trf) have been based on a neutral shift in the isoelectric focusing (IEF) pattern or on a reduction in the negative charge, allowing resolution by anion-exchange chromatography. Our purpose was to develop a method of resolution and relative quantification of Trf isoforms using online immunoaffinity liquid chromatography-mass spectrometry (LC-MS). METHODS: Serum (25 microL) was diluted with 100 microL of water before application to an immunoaffinity column that sequestered Trf isoforms. Trf isoforms were eluted from the immunoaffinity column, concentrated on a C4 column, eluted from the C4 column, and introduced into the mass spectrometer. Analysis of the Trf isoforms was entirely automated and completed in <10 min per sample. RESULTS: The LC-MS method demonstrated that the major abnormal Trf isoforms in CDG lack one complete oligosaccharide structure (mono-oligosaccharide) or both oligosaccharide structures (a-oligosaccharide), but not the sialic acids, as presumed on the basis of IEF methods. Calculation of relative ratios among three possible species (mono-/di-oligosaccharide and a-/di-oligosaccharide) is reproducible [mean intra- and interassay CVs were 9.3% (n = 10) and 10% (n = 5), respectively]. A reference range for patients <18 years was determined by analysis of 209 samples (for mono-/di-oligosaccharide, the median was 0.041 and the range was 0.018-0.083; for a-/di-oligosaccharide, the median was 0.007 and the range was 0.002-0.036). Comparison of data obtained with an affinity chromatography-IEF method and the LC-MS method demonstrated equivalence in the interpreted results (n = 170). CONCLUSIONS: Advantages of the LC-MS method include improved sensitivity, minimal sample preparation, and an analysis time of <10 min. The method was automated, which allowed high throughput, with >100 samples analyzed in a single day. Moreover, the nature of the oligosaccharide defect in CDG is accurately reflected by mass resolution, and subtle oligosaccharide truncations may also be detected by this method.

The association of dietary fat with serum cholesterol in vegetarians: the effect of dietary assessment on the correlation coefficient.

The biologic relation between dietary fats and serum cholesterol established in controlled dietary studies usually has not been found in cross-sectional studies of the general population. In vegetarian groups, dietary variables and serum cholesterol have been correlated significantly. To examine the role of technique of dietary assessment versus the dietary pattern of vegetarians, the authors studied the relation of diet with total serum cholesterol in 46 predominantly vegetarian adults in the Boston, Massachusetts, area in 1973-1974. The basis of the dietary information was 10-day diet records. Total serum cholesterol was positively associated with dietary cholesterol (r = 0.53) and saturated fatty acids (r = 0.50) in partial correlation analysis adjusted for age, sex, and triceps skinfold. The use of one-day dietary records lowered these correlation coefficients to about 0.3. Analysis of the components of variation of nutrient intake demonstrated that the vegetarians had a lower within-person variance, a higher between-person variance, or both compared with nonvegetarian study groups. Biologic responsiveness to dietary fat in the vegetarians was similar to that predicted by the Keys equation derived from nonvegetarians. Therefore, multiple-day averaging of dietary records and relatively smaller ratio of within-person to between-person variation in intake favor the detection of cross-sectional associations of diet with serum cholesterol.

Factors predicting a successful outcome after pharmacologic bowel compensation.

OBJECTIVES: The authors determined those factors that predict a successful outcome in patients who receive pharmacologic agents to promote bowel absorption after massive intestinal resection. SUMMARY BACKGROUND DATA: Patients with the short bowel syndrome are maintained on long-term total parenteral nutrition (TPN) or more frequently considered for intestinal transplantation as part of their treatment program. The authors have administered a combination of trophic agents and a specialized diet to further enhance intestinal compensation and optimize nutrient absorption in patients with intestinal failure. METHODS: Forty-five TPN-dependent adults with a jejunal-ileal remnant < or = 50 cm and a portion of colon in continuity were treated with growth hormone, glutamine, and a modified diet for 4 weeks and observed for an average of 1.8 years. RESULTS: The average age of the patients was 43 years, the average jejunal-ileal length was 23 cm, and the average length of time the patient received TPN was 4.3 years. After 4 weeks of therapy, 26 (58%) were free of TPN support. Predictors of a favorable response included greater bowel length, lower body weight, and greater bowel length-body weight ratio. At follow-up, the percentage of patients who were not receiving TPN had fallen to 40%. CONCLUSIONS: Approximately half of a group of patients, thought to have absorptive surface area inadequate to be independent of TPN support, can maintain themselves on enteral feedings after this intestinal rehabilitation program. Because of the risk, costs, and alterations in lifestyle associated with long-term TPN or intestinal transplantation or both, it seems prudent to consider a program of bowel rehabilitation with an individual patient before embarking on another therapeutic plan.