bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Relationship between Obesity and Serum 1,25-Dihydroxy Vitamin D Concentrations in Healthy Adults
Authors: Parikh Shamik J. , Edelman Marni , Uwaifo Gabriel I. , Freedman Renee J. , Semega-Janneh Mariama , Reynolds James , Yanovski Jack A. 
Published: March 2004

Abstract
Several previous reports of small cohorts have found significantly higher serum 1,25-dihydroxy vitamin D (1,25-vit D) in obese compared with nonobese whites. Based on these reports and on recent in vitro studies of adipocytes which suggest that administration of 1,25-vit D can stimulate lipogenesis and inhibit lipolysis, some investigators have proposed that high 1,25-vit D may play a role in promoting or maintaining adipocyte triglyceride stores in obese adults. To test the hypothesis that obesity is commonly associated with increased 1,25-vit D, we examined the relationships between calciotropic hormones and body adiposity in a large cohort of healthy adults. Serum intact PTH, 25-hydroxy vitamin D, and 1,25-vit D were measured in the postabsorptive state in 302 healthy adults who were Caucasian (n = 190; 71% female), African-American (n = 84; 89% female), and of other race/ethnicity (n = 28; 61% female). Results from the 154 obese subjects [body mass index (BMI) 37.3 ± 5.8 kg/m2; range, 30.1–58.2 kg/m2] were compared with those from 148 nonobese (BMI 25.6 ± 2.9 kg/m2; range, 18.0–29.9 kg/m2) age-, race-, and sex-matched participants. Body composition was measured by dual energy x-ray absorptiometry. Serum intact PTH was positively correlated with both BMI (r = 0.42; P &lt; 0.0001) and body fat mass (r = 0.37; P &lt; 0.0001). Serum 25-hydroxy vitamin D was negatively correlated with BMI (r = −0.4; P &lt; 0.0001) and body fat mass (r = −0.41; P &lt; 0.0001). Serum 1,25-vit D was also negatively correlated with BMI (r = −0.26; P &lt; 0.0001) and body fat mass (r = −0.25; P = 0.0001). Serum 1,25-vit D was significantly lower in obese than nonobese subjects (105.7 ± 41.1 vs. 124.8 ± 36.7 pmol/liter; P &lt; 0.0001) in both Caucasian and African-American adults. We conclude that, because 1,25-vit D concentrations fall with increasing adiposity, it appears unlikely that elevation in 1,25-vit D is an important hormonal mechanism causing or maintaining obesity in adults.
Physiological Induction of Transient Receptor Potential Canonical Proteins, Calcium Entry Channels, in Human Myometrium: Influence of Pregnancy, Labor, and Interleukin-1β
Authors: Dalrymple A. , Slater D. M. , Poston L. , Tribe R. M. 
Published: March 2004

Abstract
This study investigated gestational regulation of transient receptor potential canonical (TrpC) proteins, putative calcium entry channels in human myometrium, and the potential modulation of TrpC expression by IL–1β, a cytokine implicated in labor. Total RNA and proteins were isolated from myometrial biopsies obtained from NP women, pregnant women at term not in labor (TNL), or term active labor (TAL) and from primary cultured human myometrial smooth muscle cells incubated with IL–1β or IL–1β with or without nimesulide. Semiquantitative RT-PCR demonstrated significant up-regulation of TrpC1 in TAL and TNL (P ≤ 0.01) and TrpC6 (P ≤ 0.01) and TrpC7 (P ≤ 0.05) in TAL samples. TrpC3 and TrpC4 mRNA expression was unaffected. Western blot demonstrated significant up-regulation of TrpC1 in TAL and TNL (P ≤ 0.05) and TrpC3 (P ≤ 0.01), TrpC4 (P ≤ 0.05), and TrpC6 (P ≤ 0.01) in TAL samples. IL–1β did not alter TrpC1, 3, 4, 6, or 7 mRNA expression; but IL–1β exclusively up-regulated TrpC3 protein expression (P ≤ 0.05). TrpC3 up-regulation was unaffected by cyclooxygenase blockade. These data demonstrate physiological regulation of TrpC mRNA and protein and suggest an important role for TrpC proteins in human myometrium during labor.
Adipose Tissue Adiponectin Production and Adiponectin Serum Concentration in Human Obesity and Insulin Resistance
Authors: Hoffstedt Johan , Arvidsson Elisabet , Sjölin Eva , Wåhlén Kerstin , Arner Peter 
Published: March 2004

Abstract
The role of adiponectin production for the circulating protein concentration in human obesity and insulin resistance is unclear. We measured serum concentration and sc adipose tissue secretion rate of adiponectin in 77 obese and 23 nonobese women with a varying degree of insulin sensitivity. The serum adiponectin concentration was similar in both groups. In obesity, adiponectin adipose tissue secretion rate per weight unit was reduced by 30% (P = 0.01), whereas total body fat secretion rate was increased by 100% (P &lt; 0.0001). In the group being most insulin resistant (1/3), serum concentration (P &lt; 0.001) and adipose tissue secretion rate per tissue weight (P &lt; 0.05) were reduced, whereas total body fat secretion rate was increased (P &lt; 0.01), by about 30%. The adipose tissue secretion rate of adiponectin was related to the serum concentration (P = 0.005) but explained only about 10% of the interindividual variation in circulating adiponectin and insulin sensitivity. The plasma adiponectin half life was long, 2.5 h. In conclusion, the role of protein secretion for the circulating concentration of adiponectin and insulin sensitivity under these conditions is minor because adiponectin turnover rate is slow. Although increased in obesity and insulin resistance, total body production of adiponectin is insufficient to raise the circulating concentration, may be due to reduced secretion rate per tissue unit.
Effects of Aromatase Inhibition in Elderly Men with Low or Borderline-Low Serum Testosterone Levels
Authors: Leder Benjamin Z. , Rohrer Jacqueline L. , Rubin Stephen D. , Gallo Jose , Longcope Christopher 
Published: March 2004

AbstractAs men age, serum testosterone levels decrease, a factor that may contribute to some aspects of age-related physiological deterioration. Although androgen replacement has been shown to have beneficial effects in frankly hypogonadal men, its use in elderly men with borderline hypogonadism is controversial. Furthermore, current testosterone replacement methods have important limitations.We investigated the ability of the orally administered aromatase inhibitor, anastrozole, to increase endogenous testosterone production in 37 elderly men (aged 62–74 yr) with screening serum testosterone levels less than 350 ng/dl. Subjects were randomized in a double-blind fashion to the following 12-wk oral regimens: group 1: anastrozole 1 mg daily (n = 12); group 2: anastrozole 1 mg twice weekly (n = 11); and group 3: placebo daily (n = 14). Hormone levels, quality of life (MOS Short-Form Health Survey), sexual function (International Index of Erectile Function), benign prostate hyperplasia severity (American Urological Association Symptom Index Score), prostate-specific antigen, and measures of safety were compared among groups.Mean ± sd bioavailable testosterone increased from 99 ± 31 to 207 ± 65 ng/dl in group 1 and from 115 ± 37 to 178 ± 55 ng/dl in group 2 (P &lt; 0.001 vs. placebo for both groups and P = 0.054 group 1 vs. group 2). Total testosterone levels increased from 343 ± 61 to 572 ± 139 ng/dl in group 1 and from 397 ± 106 to 520 ± 91 ng/dl in group 2 (P &lt; 0.001 vs. placebo for both groups and P = 0.012 group 1 vs. group 2). Serum estradiol levels decreased from 26 ± 8 to 17 ± 6 pg/ml in group 1 and from 27 ± 8 to 17 ± 5 pg/ml in group 2 (P &lt; 0.001 vs. placebo for both groups and P = NS group 1 vs. group 2). Serum LH levels increased from 5.1 ± 4.8 to 7.9 ± 6.5 U/liter and from 4.1 ± 1.6 to 7.2 ± 2.8 U/liter in groups 1 and 2, respectively (P = 0.007 group 1 vs. placebo, P = 0.003 group 2 vs. placebo, and P = NS group 1 vs. group 2). Scores for hematocrit, MOS Short-Form Health Survey, International Index of Erectile Function, and American Urological Association Symptom Index Score did not change. Serum prostate-specific antigen levels increased in group 2 only (1.7 ± 1.0 to 2.2 ± 1.5 ng/ml, P = 0.031, compared with placebo).These data demonstrate that aromatase inhibition increases serum bioavailable and total testosterone levels to the youthful normal range in older men with mild hypogonadism. Serum estradiol levels decrease modestly but remain within the normal male range. The physiological consequences of these changes remain to be determined.
BRAF T1796A Transversion Mutation in Various Thyroid Neoplasms
Authors: Xing M. , Vasko V. , Tallini G. , Larin A. , Wu Gujun , Udelsman R. , Ringel M. D. , Ladenson P. W. , Sidransky D. 
Published: March 2004

Abstract
A high prevalence of activating mutation of the B type Raf kinase (BRAF) gene was recently reported in papillary thyroid cancer (PTC). However, the frequency of this mutation in several other types of thyroid neoplasms was not thoroughly investigated. In the present study, in addition to PTC, we evaluated various thyroid tumor types for the most common BRAF T1796A mutation by direct genomic DNA sequencing. We found a high and similar frequency (45%) of the BRAF T1796A mutation in two geographically distinct PTC patient populations: one composed of sporadic cases from North America, and the other from Kiev, Ukraine, that included individuals who were exposed to the Chernobyl nuclear accident. In contrast, we found BRAF mutation in only 20% of anaplastic thyroid cancers and no mutation in medullary thyroid cancers and benign thyroid hyperplasia. We also confirmed previous reports that the BRAF T1796A mutation did not occur in benign thyroid adenomas and follicular thyroid cancers. Specific analysis of the Ukraine patients with confirmed history of radiation exposure failed to show a higher incidence of BRAF mutation. Our results suggest that frequent occurrence of BRAF mutation is inherently associated with PTC, irrespective of geographic origin, and is apparently not a radiation-susceptible mutation. The lack or low prevalence of BRAF mutation in other thyroid neoplasms is consistent with the notion that other previously defined genetic alterations on the same signaling pathway are sufficient to cause tumorigenesis in most thyroid neoplasms.
Validation of Insulin Sensitivity Indices from Oral Glucose Tolerance Test Parameters in Obese Children and Adolescents
Authors: Yeckel Catherine W. , Weiss Ram , Dziura James , Taksali Sara E. , Dufour Sylvie , Burgert Tania S. , Tamborlane William V. , Caprio Sonia 
Published: March 2004

Abstract
Given the extreme increase in prediabetes, type 2 diabetes, and the potential for metabolic syndrome in obese youth, identifying simplified indexes for assessing stimulated insulin sensitivity is critical. The purpose of this study was validation of two surrogate indexes of insulin sensitivity determined from the oral glucose tolerance test (OGTT): the composite whole body insulin sensitivity index (WBISI) and the insulin sensitivity index (ISI). An obese population (aged 8–18 yr) of normal and impaired glucose tolerance individuals was studied. One group (n = 38) performed both the euglycemic-hyperinsulinemic clamp and OGTT for comparison of insulin sensitivity measurements as well as 1H-magnetic resonance spectroscopy estimates of intramyocellular lipid content. Another larger (n = 368) cohort participated only in an OGTT. Both the WBISI and ISI represented good estimates (r = 0.78 and 0.74; P &lt; 0.0005) for clamp-derived insulin sensitivity (glucose disposed, M-value), respectively. In the large cohort, the surrogate indexes demonstrated the shift toward poorer function and increased risk profile as a function of insulin resistance. Additionally, the WBISI and ISI correlated with intramyocellular lipid content (r = −0.74 and −0.71; P &lt; 0.0001), a tissue marker for insulin resistance. Insulin sensitivity can be estimated using plasma glucose and insulin responses derived from the OGTT in obese youth with normal and impaired glucose tolerance.
Effects of the Peroxisomal Proliferator-Activated Receptor-γ Agonist Pioglitazone on Renal and Hormonal Responses to Salt in Healthy Men
Authors: Zanchi Anne , Chiolero Arnaud , Maillard Marc , Nussberger Jürg , Brunner Hans-Rudolf , Burnier Michel 
Published: March 2004

AbstractGlitazones are used in the treatment of type 2 diabetes as efficient insulin sensitizers. They can, however, induce peripheral edema through an unknown mechanism in up to 18% of cases. In this double-blind, randomized, placebo-controlled, four-way, cross-over study, we examined the effects of a 6-wk administration of pioglitazone (45 mg daily) or placebo on the blood pressure, hormonal, and renal hemodynamic and tubular responses to a low (LS) and a high (HS) sodium diet in healthy volunteers. Pioglitazone had no effect on the systemic and renal hemodynamic responses to salt, except for an increase in daytime heart rate. Urinary sodium excretion and lithium clearance were lower with pioglitazone, particularly with the LS diet (P &lt; 0.05), suggesting increased sodium reabsorption at the proximal tubule. Pioglitazone significantly increased plasma renin activity with the LS (P = 0.02) and HS (P = 0.03) diets. Similar trends were observed with aldosterone. Atrial natriuretic levels did not change with pioglitazone. Body weight increased with pioglitazone in most subjects. Pioglitazone stimulates plasma renin activity and favors sodium retention and weight gain in healthy volunteers. These effects could contribute to the development of edema in some subjects treated with glitazones.
Gastric Bypass Surgery for Morbid Obesity Leads to an Increase in Bone Turnover and a Decrease in Bone Mass
Authors: Coates Penelope S. , Fernstrom John D. , Fernstrom Madelyn H. , Schauer Philip R. , Greenspan Susan L. 
Published: March 2004

Abstract
Little is known about the effects on the skeleton of laparoscopic Roux-en-Y gastric bypass (LRGB) surgery for morbid obesity and subsequent weight loss. We compared 25 patients who had undergone LRGB 11 ± 3 months previously with 30 obese controls matched for age, gender, and menopausal status. Compared with obese controls, patients post LRGB had significantly lower weight (92 ± 16 vs. 133 ± 20 kg; P &lt; 0.001) and body mass index (31 ± 5 vs. 48 ± 7 kg/m2; P &lt; 0.001). Markers of bone turnover were significantly elevated in patients post LRGB compared with controls (urinary N-telopeptide cross-linked collagen type 1, 93 ± 38 vs. 24 ± 11 nmol bone collagen equivalents per mmol creatinine; and osteocalcin, 11.6 ± 3.4 vs. 7.6 ± 3.6 ng/ml; both P &lt; 0.001). Fifteen patients were studied prospectively for an average of 9 months after LRGB. They lost 37 ± 9 kg and had a 29 ± 8% fall in body mass index (both P &lt; 0.001). Urinary N-telopeptide cross-linked collagen type 1 increased by 174 ± 168% at 3 months (P &lt; 0.01) and 319 ± 187% at 9 months (P &lt; 0.01). Bone mineral density decreased significantly at the total hip (7.8 ± 4.8%; P &lt; 0.001), trochanter (9.3 ± 5.7%; P &lt; 0.001), and total body (1.6 ± 2.0%; P &lt; 0.05), with significant decreases in bone mineral content at these sites.
In summary, within 3 to 9 months after LRGB, morbidly obese patients have an increase in bone resorption associated with a decrease in bone mass. Additional studies are needed to examine these findings over the longer term.
Physical Properties of Monofluorodimethyl Carbonate
Authors: Takehara Masahiro , Watanabe Susumu , Nanbu Noritoshi , Ue Makoto , Sasaki Yukio 
Published: March 2004

Abstract
Partial fluorination of solvents can improve various physical properties because of the polar effect. We have investigated the temperature dependence of relative permittivity (εr), viscosity (η), refractive index (nd), and density (ρ) of monofluorodimethyl carbonate (MFDMC) over a range of 10 to 70 °C and compared the physical properties with those of dimethyl carbonate (DMC). The εr, η, and ρ of the MFDMC are higher than those of the DMC, whereas the nd becomes lower.
Pendleian (early Serpukhovian) marine carbonates from SW Spain: sedimentology, biostratigraphy and depositional model
Authors: Cózar P. , Rodríguez S. 
Published: March 2004

AbstractThe San Antonio–La Juliana tectono‐sedimentary unit contains the only Namurian marine carbonates in the southwestern part of the Iberian Peninsula. The analysis of this unit is fundamental in understanding the sedimentary evolution and tectonic movements which operated during the Namurian in this area. Using foraminifera the succession has been assigned to two biozones (Zones 17 and 18), both occurring in the Pendleian (early Namurian). Seven stratigraphic sections have been analysed: San Antonio, Burjadillo, Lavadero de la Mina, Cornuda, Lozana, Caridad and Via Crucis. The stratigraphic succession of the San Antonio–La Juliana Unit consists of olistolites in the basal part, with common debris‐flow deposits (mainly of carbonates, with minor siliciclastic rocks), and turbidites, all of them embedded in shales. These rocks, interpeted as slope deposits, pass up into shallow‐water platform facies, with sediments characteristic of the inner platform and tidal flats. Above these rocks, terrigenous deltaic deposits occur. Thus, the stratigraphic sections show an overall shallowing‐upward trend. The isolation of some outcrops, and the duplication and absence of some parts of the stratigraphic succession are explained by tectonic movements. Overall, tectonic factors seem to be the main control rather than glacio‐eustatic or autocyclic processes, and sedimentation took place in a strike‐slip regime. Copyright © 2004 John Wiley & Sons, Ltd.
Magnitude of lateral displacement on the Crevillente Fault Zone (Betic Cordillera, SE Spain): stratigraphical and sedimentological considerations
Authors: Nieto L. M. , Rey J. 
Published: March 2004

AbstractThe Crevillente Fault Zone (CFZ) comprises a system of northeast to southwest oriented dextral faults that extend for some 600 km in the External Zones of the Betic Cordillera (SE Spain). The magnitude of lateral displacement related to this fault zone is not well constrained, and it is considered to be between 20 and 400 km. The stratigraphical and sedimentological criteria used in this work have proven effective in quantifying the magnitude of the displacement along this structure. We have analysed an oolitic turbidite facies in the Middle Jurassic of the Sierra de Ricote (Median Subbetic of Murcia Province). A detailed revision of ooidal limestone outcrops has revealed that the source area of these deposits was to the Internal Subbetic zone, north of Vélez Rubio (Almería Province). These two tectonic units, the Median and Internal Subbetic, are currently 75 km from each other and separated by the CFZ. The conclusions arising from our stratigraphical, petrological and sedimentological studies favour interpretation of a 75–100 km lateral displacement. After restoring the Late Jurassic–Cretaceous anticlockwise rotation of Iberia, the CFZ appears to belong to the E–W palaeofault system that is related to the extension of the South Iberian Continental Margin (SICM). Copyright © 2004 John Wiley & Sons, Ltd.
New designer drug 1‐(3,4‐methylenedioxybenzyl) piperazine (MDBP): studies on its metabolism and toxicological detection in rat urine using gas chromatography/mass spectrometry
Authors: Staack Roland F. , Maurer Hans H. 
Published: March 2004

AbstractStudies are described on the metabolism and toxicological analysis of the piperazine‐derived designer drug 1‐(3,4‐methylenedioxybenzyl)piperazine (MDBP) in rat urine using gas chromatography/mass spectrometry (GC/MS). The identified metabolites indicated that MDBP was metabolized by demethylenation and subsequent methylation to N‐(4‐hydroxy‐3‐methoxybenzyl)piperazine followed by partial glucuronidation or sulfation. Additionally, degradation of the piperazine moiety to N‐(3,4‐methylenedioxybenzyl)ethylenediamine and 3,4‐methylenedioxybenzylamine and N‐dealkylation to piperazine were observed. The authors' systematic toxicological analysis (STA) procedure using full‐scan GC/MS after acid hydrolysis, liquid/liquid extraction and microwave‐assisted acetylation allowed the detection of MDBP and its above‐mentioned metabolites in rat urine after single administration of a dose calculated from the doses commonly taken by drug users. Assuming similar metabolism, the described STA procedure should be suitable for proof of an intake of MDBP by analysis of human urine. Copyright © 2004 John Wiley & Sons, Ltd.
Protonated silanoic acid HSi(OH)2+ and its neutral counterpart: a tandem mass spectrometric and CBS‐QB3 computational study
Authors: Srikanth R. , Bhanuprakash K. , Srinivas R. , Wong Cathy Y. , Terlouw Johan K. 
Published: March 2004

AbstractProtonated silanoic acid, HSi(OH)2+, 1a+, is cleanly generated by the dissociative electron ionization of triethoxysilane, HSi(OC2H5)3, and tetraethoxysilane, Si(OC2H5)4. This follows from tandem mass spectrometric experiments and CBS‐QB3 model chemistry calculations. The calculations predict that 1a+ (ΔHf(298 K) = 205 kJ mol−1) is separated by high barriers from its isomers HOSiOH2+, 1b+ and HSi(O)OH2+, 1c+. Low‐energy (metastable) ions 1a+ dissociate by loss of H2O via the pathway 1a+ → 1b+ → SiOH+ + H2O. Analysis of the metastable peak for this process confirms that the isomerization step 1a+ → 1b+ is rate determining. The calculations further predict that the incipient ions 1b+ communicate via a low barrier with the proton‐bound dimer SiO···H···OH2+, 1d+. This dimer ion is much lower in energy than its counterpart OSi···H···OH2+, 1e+, which is calculated to be only marginally stable. A comparison of the potential energy diagram for the silicon‐containing ions 1a+–1e+ with that of their carbon analogues reveals that the dissociation chemistries of HSi(OH)2+ and HC(OH)2+ are only superficially similar. Neutralization–reionization experiments confirm the theoretical prediction that the HSi(OH)2• radical (ΔHf(298 K) = −455 kJ mol−1) is a stable species in the rarefied gas phase. However, owing to a mismatch of Franck–Condon factors a large fraction of the neutralized ions dissociates by loss of H• yielding Si(OH)2. Copyright © 2004 John Wiley & Sons, Ltd.
A Top‐down method for the determination of residue‐specific solvent accessibility in proteins
Authors: Novak Petr , Kruppa Gary H. , Young Malin M. , Schoeniger Joe 
Published: March 2004

AbstractWe present a method employing top‐down Fourier transform mass spectrometry (FTMS) for the rapid profiling of amino acid side‐chain reactivity. The reactivity of side‐chain groups can be used to infer residue‐specific solvent accessibility and can also be used in the same way as H/D exchange reactions to probe protein structure and interactions. We probed the reactivity of the N‐terminal and ε‐lysine amino groups of ubiquitin by reaction with N‐hydroxysuccinimidyl acetate (NHSAc), which specifically acetylates primary amines. Using a hybrid Q‐FTMS instrument, we observed several series of multiply acetylated ubiquitin ions that varied with the NHSAc : protein stoichiometry. We isolated and fragmented each member of the series of acetylated ubiquitin ions in the front end of the instrument and measured the fragment ion masses in the FTMS analyzer cell to determine which residue positions were modified. As we increased the NHSAc : protein stoichiometric ratio, identification of the fragments from native protein and protein with successively increasing modification allowed the assignment of the complete order of reactivity of the primary amino groups in ubiquitin (Met 1 ≈ Lys 6 ≈ Lys 48 ≈ Lys 63 > Lys 33 > Lys 11 > Lys 27, Lys 29). These results are in excellent agreement with the reactivity expected from other studies and predicted from the known crystal structure of ubiquitin. The top‐down approach eliminates the need for proteolytic digestion, high‐performance liquid chromatographic separations and all other chemical steps except the labeling reaction, making it rapid and amenable to automation using small quantities of protein. Copyright © 2004 John Wiley & Sons, Ltd.