Differential effects of gastric bypass and banding on circulating gut hormone and leptin levels

Objective: To quantify plasma concentrations of hormones that regulate energy homeostasis in order to establish possible mechanisms for greater weight loss after Roux‐en‐Y gastric bypass (RYGBP) compared with gastric banding (BND). Research Methods and Procedures: Four groups of women were studied: lean (n = 8; mean BMI, 21.6 kg/m²); BND (n = 9; BMI, 35.8; 25% weight loss), RYGBP (n = 9; BMI, 34.2; 36% weight loss), and controls matched for BMI to the surgical groups (n = 11; BMI, 34.4). Results: Fasting total peptide YY (PYY) and PYY_(3–36) immunoreactivity were similar among all groups, but the postprandial response in the RYGBP group was exaggerated, such that 30 minutes after the meal, total and PYY_(3–36) levels were 2‐ to 4‐fold greater compared with all other groups. Maximal postprandial suppression of total ghrelin was blunted in the BND group (13%) compared with RYGBP (27%). Postprandial suppression of octanoylated ghrelin was also less in BND (29%) compared with RYGBP (56%). Fasting insulin was lower in RYGBP (6.6 μU/mL) compared with BND (10.0 μU/mL). Compared with lean controls, leptin concentrations were significantly higher in BND but not in RYGBP. There was a greater increase in post‐meal satiety in the RYGBP group compared with BND and overweight controls. Discussion: The differences between RYGBP and BND subjects in postprandial concentrations of PYY and ghrelin would be expected to promote increased satiety and earlier meal termination in RYGBP and may aid in greater weight loss. The differences in insulin and leptin concentrations associated with these procedures may also reflect differences in insulin sensitivity and energy partitioning.     

Pituitary metabolism of 5alpha-androstane-3beta-17beta-diol: intense and rapid conversion into 5alpha-androstane-3beta,6alpha,17beta-triol and 5alpha-androstane-3beta,7alpha, 17beta-triol.

In the male rat pituitary, 5alpha-androstane-3beta, 17beta-diol (3beta-diol) is extensively metabolized into polar steroids. They were identified as 5alpha-androstane-3beta, 6alpha-17beta-triol (6alpha-triol) and 5alpha-androstane-3beta, 7alpha, 17beta-triol (7alpha-triol). 6-alpha-Triol represents 53% and 7alpha-Triol 28% of the total 3beta-diol metabolites. The remaining percentage is related to 6beta and 7beta isomers. The biological role of triols is still unknown.     

Regulation of adenylate cyclase in cultured cardiocytes from neonatal rats by adenosine and other agonists

The presence of adenosine receptors coupled to adenylate cyclase in cultured cardiocytes from atria and ventricles from neonatal rats is demonstrated in these studies. N-Ethylcarboxamideadenosine (NECA), l-N⁶-phenylisopropyladenosine (PIA), and 2-chloroadenosine (2-cl-Ado) stimulated adenylate cyclase in a concentration-dependent manner in both cultured atrial and ventricular cells. The order of potency of stimulation was NECA > PIA > 2-cl-Ado. The stimulation of adenylate cyclase by NECA was enhanced by guanine nucleotides and was blocked by 3-isobutyl-1-methylxanthine in both these cells. Other agonists such as epinephrine, norepinephrine, dopamine, F^?, and forskolin were also able to stimulate adenylate cyclase, although the extent of stimulation by these agents was higher in ventricular than in atrial cells. The stimulation of adenylate cyclase by epinephrine and norepinephrine was inhibited by propranolol but not by phentolamine. On the other hand, phentolamine, propranolol, and haloperidol inhibited dopamine-stimulated adenylate cyclase activity to the same extent. Forskolin, at its maximal concentration, potentiated the stimulatory effect of epinephrine, norepinephrine, and dopamine on adenylate cyclase in both atrial and ventricular cardiocytes, but the interaction of NECA with epinephrine, norepinephrine, or dopamine was different in atrial and ventricular cells. The stimulation by an optimal concentration of NECA was additive with maximal stimulation by the catecholamines in atrial cells but not in ventricular cells. The data suggest the existence of adenosine “Ra” and catecholamine receptors in cultured atrial and ventricular cardiocytes. It can be postulated that adenosine in addition to its role as a potent vasodilator might regulate cardiac performance through its interaction with “Ra” receptors associated with adenylate cyclase. The difference in the mode of interaction of adenosine with catecholamines in atrial and ventricular cells suggests that the mechanism by which these agents activate adenylate cyclase may be different in these cells.     

帕米尔红景天化学成分的研究

从帕米尔红暾天根中分离得到八个成分（Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ、Ⅵ、Ⅶ、Ⅷ）,经ＵＶ,ＩＲ,＾１ＨＮＭＲ,＾１３ＣＮＭＲ及化学方法鉴定了它们的结构,分别是正二十二（Ⅰ）,Ｇｌｕｔｉｎ－５－ｅｎ－３ｏｎｅ（Ⅱ）,β－谷甾醇（Ⅲ）,二十六烷酸（Ⅳ）,对羟基乙酮（Ⅴ）,山东奈酚（Ⅳ）,没食子酸（Ⅶ）,云杉甙（Ⅷ）,这些成分均为首次从该植物中获得。     

Hyperexpression and Analysis of choB Encoding Cholesterol Oxidase of Brevibacterium sterolicum in Escherichia coli and Streptomyces lividans.

We examined the expression of choB, encoding cholesterol oxidase of Brevibacterium sterolicum ATCC 21387, in Escherichia coli JM105 and Streptomyces lividans TK23 using various deletion DNA fragments within the 5′-flanking region. The enzyme activity could be detected intracellularly in E. coli only when the 5′-flanking region was reduced to less than 256-bp and choB was transcribed by the lac promoter. A large amount of the enzyme were produced as inactive inclusion bodies when ChoB protein was fused with the NH₂-terminal portion of LacZ protein. In contrast, choB with more than 256-bp of the 5′-flanking region was efficiently expressed in S. lividans TK23, and about 85 times as much of the active enzyme (170 U/ml) was secreted into the culture filtrate as with B. sterolicum in flask culture. These results suggest that the promoter of choB exist within 256-bp of the 5′-flanking region and can be efficiently recognized by the RNA polymerase of S. lividans. The characteristics of the enzyme purified from the culture filtrate of the S. lividans transformant and that of B. sterolicum were identical although the NH₂-terminal amino acid sequence of the enzyme from the S. lividans transformant was 6 amino acids shorter than that from B. sterolicum.     

FFT method to compute solution X-ray scattering curves

We present an efficient algorithm to compute X-ray intensities scattered by macromolecules in solution, from atomic positions found in crystal structures. The algorithm applied the FAst Fourier Transform to an electron density map created from the atomic coordinates and corrected for solvent density. We compute scattering curves for both allosteric forms of E. coli aspartate carbamoyltransferase. Calculated intensities are in agreement with the ones measured by Moddy et al. [1,2] which shows that the structures observed in solution in the presence or in the absence of a substrate analogue do correspond to those of two crystal forms analyzea by Lipscomb and collaborators [3,4,5].     

Galets aménagés en provenance des terrasses supérieures du Rhône au sud de Lyon (Sud-Est de la France)

Between 1990 and 1993, we found 175 pebble-tools and two flake-tools on the western high-terrace south of Lyon (Southeast, France) at two different levels (290 m and 235 m NN). Most of them show the classical spectrum of choppers and chopping-tools, joined by six protobifaces. They all belong to the developed Olduvan (Olduvan II). On the lower terrace, corresponding with its younger age, we met a more progressive pebble-tool culture. Both stocks are secondary sites, brought from the East by the most extreme tongue of the Rhône glacier and, therefore, cannot be dated exactly.     

Mössbauer spectroscopy study of iron overloaded livers

Absorption 57Fe M?ssbauer spectra have been carried out directly on fresh or lyophylized tissues of liver with either normal iron depot or iron overload. Two types of overloading have been studied: primary iron overload due to an excessive intestinal iron absorption and secondary iron overload (hemosiderosis) produced in beta-thalassemia patients by hypertransfusional therapeutics. The M?ssbauer spectra, at room temperature, 77 and 4.2 K, on normal liver samples, are typical for the ferritin-hemosiderin compounds. In the spectra, performed on hemosiderosis liver samples, there appears, in addition to ferritin and hemosiderin, a new iron molecular environment, typical of high spin ferric iron and characterized by a superparamagnetic behaviour which begins at high temperature (above 77 K). This new component does not show up in the primary iron overload cases and seems characteristic of the physiological process which induces the iron overload.     

The pollen tube clear zone:Clues to the mechanism of polarized growth

Pollen tubes usually exhibit a prominent region at their apex called the “clear zone” because it lacks light refracting amyloplasts. A robust, long clear zone often associates with fast growing pollen ...     

Bone and Gastric Bypass Surgery: Effects of Dietary Calcium and Vitamin D

Objective:To examine bone mass and metabolism in women who had previously undergone Roux‐en‐Y gastric bypass (RYGB) and determine the effect of supplementation with calcium (Ca) and vitamin D. Research Methods and Procedures: Bone mineral density and bone mineral content (BMC) were examined in 44 RYGB women (≥3 years post‐surgery; 31% weight loss; BMI, 34 kg/m²) and compared with age‐ and weight‐matched control (CNT) women (n = 65). In a separate analysis, RYGB women who presented with low bone mass (n = 13) were supplemented to a total 1.2 g Ca/d and 8 μg vitamin D/d over 6 months and compared with an unsupplemented CNT group (n = 13). Bone mass and turnover and serum parathyroid hormone (PTH) and 25‐hydroxyvitamin D were measured. Results:Bone mass did not differ between premenopausal RYGB and CNT women (42 ± 5 years), whereas postmenopausal RYGB women (55 ± 7 years) had higher bone mineral density and BMC at the lumbar spine and lower BMC at the femoral neck. Before and after dietary supplementation, bone mass was similar, and serum PTH and markers of bone resorption were higher (p < 0.001) in RYGB compared with CNT women and did not change significantly after supplementation. Discussion: Postmenopausal RYGB women show evidence of secondary hyperparathyroidism, elevated bone resorption, and patterns of bone loss (reduced femoral neck and higher lumbar spine) similar to other subjects with hyperparathyroidism. Although a modest increase in Ca or vitamin D does not suppress PTH or bone resorption, it is possible that greater dietary supplementation may be beneficial.