Influence of testosterone propionate administered neonatally on puberty and bisexual behavior in female hamsters.

Treated female golden hamsters with oil, 3-mg, 30-mg, or 300-mg testosterone propionate (TP) as neonates in Exp I. Neonatal TP treatment delayed the onset of puberty by 4.5 days to an age near that previously reported for the male hamster. In addition, neonatal TP altered genital morphology, induced the capacity for mounting behavior, and at the highest dosage, disrupted the ability to bear and rear young. Vaginal and behavioral estrous cycles, however, were not influenced by neonatal TP. In Exp II 600-mg TP administered neonatally blocked estrous cyclicity but did not eliminate the capacity to display feminine sexual behavior. Results imply that masculinization and defeminization are separate aspects of neurobehavioral sexual differentiation, and that defeminization includes several independent physiological processes. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Surfactant protein-D regulates surfactant phospholipid homeostasis in vivo

Surfactant protein D (SP-D) is a 43-kDa member of the collectin family of collagenous lectin domain-containing proteins that is expressed in epithelial cells of the lung. The SP-D gene was targeted by homologous recombination in embryonic stem cells that were used to produce SP-D (+/-) and SP-D (-/-) mice. Both SP-D (-/-) and SP-D (+/-) mice survived normally in the perinatal and postnatal periods. Whereas no abnormalities were observed in SP-D (+/-) mice, alveolar and tissue phosphatidylcholine pool sizes were markedly increased in SP-D (-/-) mice. Increased numbers of large foamy alveolar macrophages and enlarged alveoli were also observed in SP-D (-/-) mice. Phospholipid composition was unaltered in SP-D (-/-) mice, but surfactant morphology was abnormal, consisting of dense phospholipid membranous arrays with decreased tubular myelin. The pulmonary lipoidosis in the SP-D (-/-) mice was not associated with accumulation of surfactant proteins B or C, or their mRNAs, distinguishing the disorder from alveolar proteinosis syndromes. Surfactant protein A mRNA was reduced and, SP-A protein appeared to be reduced in SP-D (-/-) compared with wild type mice. Targeting of the mouse SP-D gene caused accumulation of surfactant lipid and altered phospholipid structures, demonstrating a previously unsuspected role for SP-D in surfactant lipid homeostasis in vivo.     

Global Market for Dairy Proteins

This review examines the global market for dairy ingredients by assessing the global demand for dairy products in relation to major dairy ingredient categories. Each broad category of dairy ingredients is reviewed including its definition, production and trade status, key applications, and future trends. Ingredient categories examined include whole and skim milk powders (WMPs, SMPs), whey protein concentrates (WPCs) and whey protein isolates (WPIs), milk protein concentrates (MPCs) and milk protein isolates (MPIs), caseins, and caseinates. Increases in world population and improvements in socioeconomic conditions will continue to drive the demand for dairy products and ingredients in the future. Dairy proteins are increasingly recognized to have nutritional and functional advantages compared to many protein sources, and the variety of ingredients with different protein concentrations, functionality, and flavor can meet the needs of the increasingly global dairy consumption. A thorough understanding of the variety of ingredients, how the ingredients are derived from milk, and how the demand from particular markets affects the supply situation are critical elements in understanding the current ingredient marketplace.     

Stress-like adrenocorticotropin responses to caffeine in young healthy men

The effects of oral caffeine (3.3 mg/kg, equivalent to 2-3 cups of coffee) on plasma adrenocorticotropin (ACTH) and cortisol (CORT) were tested in 47 healthy young men at rest in a double-blind, placebo-controlled, crossover study. Following caffeine, ACTH was significantly elevated at all times from 30 min to 180 min, and CORT was elevated from 60 min to 120 min (Fs > or = 8.4, ps < 0.01). Peak increases relative to placebo were: ACTH, 33% (+5.2 pg/ml) and CORT, 30% (+2.7 micrograms/dl) at 60 min postcaffeine. The results suggest that caffeine can activate important components of the pituitary-adrenocortical response in humans during the resting state. Caffeine's known ability to increase CORT production appears at least partly due to an increase in ACTH release at the pituitary.     

VEGF enhances pulmonary vasculogenesis and disrupts lung morphogenesis in vivo

Three approximate free energy calculation methods are examined and applied to an example ligand design problem. The first of the methods uses a single simulation to estimate the relative binding free energies for related ligands that are not simulated. The second method is similar, except that it uses only first derivatives of free energy with respect to atomic parameters (most often charge, van der Waals equilibrium distance, and van der Waals well depth) to calculate free energy differences. The last method PROFEC (Pictorial Representation of Free Energy Components), generates contour maps that show how binding free energy changes when additional particles are added near the ligand. These three methods are applied to a benzamidine/trypsin complex. They each reproduce the general trends in the binding free energies, indicating that they might be useful for suggesting how ligands could be modified to improve binding and, consequently, useful in structure-based drug design.     

Physical and behavioral aspects of sexual maturation in male golden hamsters.

Male golden hamsters ( Mesocricetus auratus ) were examined from 3 to 9 wks of age for morphological, physiological, and behavioral indices of sexual maturation. Although each of the 8 variables (e.g., testis weight, seminal vesicle fluid, and rear mounts) selected for measurement displayed a unique developmental profile, a principal-components analysis of these variables resulted in the extraction of 2 principal components, one tentatively labeled physical and gross behavioral maturation (accounting for 66% of the total variance) and the other designated perfection of mounting orientation (accounting for an additional 12% of the variance). This result indicates that puberty in the male hamster is best viewed as 2 independent processes, rather than as a unitary process or as an arbitrary term applied to a variety of unrelated developmental phenomena. Advantages of using multivariate composite scores and selected univariate measurements are discussed, as are methods of comparing developmental changes in different variables. A 2nd experiment confirmed an unexpectedly early onset of androgen secretion and an unusual pattern of body weight gain. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social inhibition of sexual maturation in male prairie deer mice.

Five experiments demonstrated that the sexual maturation of male prairie deer mice (Peromyscus maniculatus bairdii) (n?=?334) that were reared with other males was inhibited in comparison with that of males reared in isolation. Inhibition occurred in males reared with 9 or 4 males of the same age, as well as in those housed with 1 adult male. This phenomenon was observed after several periods of grouping, and consequently at several ages ranging from 5 wks to 4 mo. Females did not retard the sexual development of males. Results indicate that the sexual maturation of individual deer mice is modulated by the specific composition, rather than density, of the local group. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential influence of stereoisomers of estradiol on sexual behavior of female hamsters.

Morphological and behavioral responses to estradiol-17β (E?-17β) and estradiol-17α (E?-17α) were examined in a series of 3 experiments with golden hamsters. The E?-17β augmented uterine growth to a greater extent than E?-17α. Lordosis in ovariectomized adults was elicited by treatment with E?-17β but not with E?-17α (each tested in combination with progesterone). When administered neonatally, only E?-17β disrupted estrous cyclicity in the intact female and induced the ability to mount in ovariectomized, androgen-treated adults. Results suggest the existence of a stereospecific response to estrogenic stimulation in neural tissue comparable with that occurring in the uterus. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alterations in pulmonary surfactant composition and activity after experimental lung transplantation

BACKGROUND: Adenosine has been reported to mediate the necrosis-limiting effects of ischemic preconditioning; however, it is unclear how this mediation occurs. The present study was undertaken to test the hypothesis that ischemic preconditioning increases 5'-nucleotidase activity and adenosine release during sustained ischemia and subsequent reperfusion. METHODS AND RESULTS: After thoracotomy, the left anterior descending coronary artery was cannulated and perfused with blood redirected from the left carotid artery in 32 dogs. Ischemic preconditioning was produced by four cycles in which the coronary artery was occluded and then reperfused for 5 minutes each. After the last cycle of ischemia and reperfusion, the coronary artery was occluded for 40 minutes. This was followed by 120 minutes of reperfusion. In the control group, the coronary artery was occluded for 40 minutes and reperfused for 120 minutes without ischemic preconditioning. The plasma adenosine concentration was measured and blood gases were analyzed in coronary arterial and venous blood samples taken during 120 minutes of reperfusion. Myocardial 5'-nucleotidase activity was measured before and at 40 minutes of sustained ischemia with and without ischemic preconditioning. The adenosine concentration in coronary venous blood during reperfusion was significantly higher in preconditioned hearts than in the control hearts: 1 minute after the onset of reperfusion, 546 +/- 57 versus 244 +/- 41 pmol/ml; 10 minutes after, 308 +/- 30 versus 114 +/- 14 pmol/ml; 30 minutes after, 175 +/- 24 versus 82 +/- 16 pmol/ml, respectively (p < 0.01). Ectosolic and cytosolic 5'-nucleotidase activities increased in both endocardial and epicardial myocardium in the ischemia-preconditioned hearts. Furthermore, 40 minutes of ischemia increased 5'-nucleotidase activity in ischemia-preconditioned hearts more than in control hearts. CONCLUSIONS: Ischemic preconditioning increases adenosine release and 5'-nucleotidase activity during sustained ischemia and subsequent reperfusion.