T-cell activity associated with secondary infections and implanted cysts of Echinococcus granulosus in BALB/c mice

Selected cytokine profiles of lymphocytes were assessed in BALB/c mice infected with protoscoleces of Echinococcus granulosus. Late stages of the infection (three months+) were characterized by more dominant Th2 activity with elevated IL-4 and IL-10 and reduced IFN-gamma output by Con-A and antigen stimulated splenocytes. Circumparasitic leucocytes produced mainly IL-10 by five months post infection. A peak in IFN-gamma production in the first month of infection may suggest Th1 or Th0 activity at this time and this may be correlated with initial protoscolex death. In addition, cytokine profiles from mice implanted with intact hydatid cysts were also assessed. At two weeks post implantation all cysts were still viable and cytokine production was characterized mainly by elevated IL-10 production. However, at four months post implantation, some of the cysts from two mice had been killed whilst all cysts in the remaining mouse remained viable. In the mice where dead cysts were present, elevated levels of IFN-gamma were detected from splenocytes and circumparasitic cells. Elevated IL-4 was also evident with the splenocytes. In the mouse with viable cysts IFN-gamma production was reduced Results indicate that IFN-gamma(Th1) activity may be correlated with killing of both protoscoleces and established cysts of E. granulosus.     

The localization model of rubber elasticity and the deformation of a network formed by cross-linking a strained melt

Summary The localization model of rubber elasticity is applied to the deformation behavior of a network formed by cross-linking a strained melt.     

Solvent Polarity Dependent Photophysics of a Fixed-Distance,Symmetric Chlorophyll Dimer. A Model of the Special Pair in Photosynthetic Reaction Centers

The synthesis and properties of a fixed-distance symmetric bis-pyrochlorophyllide-a molecule are described. The molecule, 1 , consists of two methyl pyrochlorophyllide-a (MePChlide-a) moieties which share a common vinyl group at the 2-position of each macrocycle. The two chlorophylls are trans to one another across the vinyl linkage. The dihedral angle between the plane of each macrocycle and the vinyl linkage is about 50°. The Q_y absorption band of this dimer occurs at 689 nm and is essentially independent of solvent. The band is red-shifted by about 27 run relative to that of MePChlide-a. The fluorescence maximum of 1 occurs at 722 nm. This is a red-shift of 49 nm relative to methyl MePChlide-a. The circular dichroism spectrum of 1 shows strong, nonconservative bands in the red region. The fluorescence quantum yield, fluorescence lifetimes, and picosecond transient absorbance kinetics all exhibit a very strong dependence on solvent polarity. The fluorescence quantum yields of 1 in toluene, butyronitrile, and N, N-dimethyl formamide (DMF) are 0.18, 0.008, and 0.002, respectively. The bleach of the 689 nm band (following excitation with a 1.5-ps, 610-nm laser pulse) recovers with single exponential time constants of 2.51 ns, 100 ps, and 64 ps in toluene, butyronitrile, and DMF, respectively. Possible mechanisms for the polarity-dependent increase of the nonradiative decay rate of 1 are considered.     

Management of thyroid nodules

Clinically apparent thyroid nodules occur in about 5 percent of the population. Because most patients with thyroid nodules present initially to their primary care physician, family physicians should have a thorough understanding of the diagnosis and treatment of thyroid nodules. The history and physical examination may be helpful in detecting thyroid nodules but are not useful in predicting malignancy. Furthermore, laboratory studies, ultrasonography and nuclear medicine scans do not reliably differentiate between benign and malignant thyroid nodules. In most cases, fine-needle aspiration biopsy can accurately identify malignant thyroid nodules. Fine-needle aspiration biopsy is safe and can be performed in an office setting.     

Emergenesis: An alternative and a confound.

Comments on the proposition of D. T. Lykken et al (see record 1993-16512-001) that there is a genetic explanation (emergenesis) for the similarity of monozygotic twins reared apart (MZA). Emergenesis is challenged and it is argued that the authors' research method is inherently confounded. An environmental explanation is suggested, which holds that MZAs' personalities are similarly molded because of their shared physical appearance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identification of an orally active, nonpeptidyl oxytocin antagonist

L-366,509, a member of a novel class of nonpeptidyl compounds, has been characterized as an orally active oxytocin (OT) antagonist. L-366,509 exhibits a moderate binding affinity (K(i) values, 370-780 nM) for the rat, rhesus and human uterine OT receptor. L-366,509 also binds to vasopressin receptor subtypes (arginine vasopressin-V1 and V2) with measurable affinity in rat (K(i) values, 25-30 microM) and primate (K(i) values, 2-6 microM) tissues. In rat uterine slices, L-366,509 inhibits (IC50 = 1.6 microM) the stimulation of phosphatidylinositol turnover induced by OT but not bradykinin. In the rat isolated uterus, L-366,509 is a competitive and reversible OT antagonist (pA2 = 7.32). In vivo, L-366,509 given i.v. (10 mg/kg) or intraduodenally (10-50 mg/kg) to rats causes a marked and long-lasting inhibition of OT-stimulated uterine activity. OT antagonist activity in a pregnant rhesus macaque (approximately day 135 gestation) is also observed with L-366,509 after i.v. or p.o. dosing. L-366,509 represents a prototype for a new chemical class of OT antagonists with significant p.o. bioavailability.     

Sex differences in sensitivity of the hypothalamic-pituitary-adrenal axis.

Two studies examined sex differences in responsiveness of the hypothalamic-pituitary-adrenal cortical axis, a major component of the stress response. The first measured pituitary-adrenal responses to ovine corticotropin-releasing hormone (oCRH) in 24 healthy men and 19 healthy women. Plasma adrenocorticotropin hormone responses to oCRH were significantly greater among women than among men. In contrast, cortisol concentrations were similar in both groups, though elevations were more prolonged in women. Differences in corticotropin-releasing activity between men and women may help account for these findings; such differences in central components of the stress response might play a role in the known epidemiological differences in diseases of stress system dysregulation between men and women. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Programs as higher level subroutines

The subroutine call is one of the most fundamental of program control constructs. Despite this, it is rarely implemented at the job control or task level in existing commercially available software systems. When the feasibility of adding a general program calling mechanism to an existing system was investigated, it was apparent that there exist constraints on the amount of state information which could be saved on behalf of the calling program. A mechanism with low run-time overhead which saves a minimal amount of state information has proven to be easily integratable into a commercially available operating system. This mechanism has had a significant impact on the ease of development and support of large systems of programs. Examples of the use of the new calling mechanism include a program development system and a recursive directory manager for hierarchical directories.     

Development of self-verbalized control of resistance to deviation.

The relative effectiveness of 2 types of self-instruction in controlling deviant behavior was assessed developmentally. 28 1st- and 20 2nd-grade boys were trained to say 1, or both, of 2 behavior instructions to themselves during a resistance-to-deviation test period. These instructions included a prohibitive rule that focused on inhibition of deviant behavior and/or a facilitative redirective instruction that focused attention and behavior toward a permissible alternative activity. Although training with the self-verbalized prohibitive rule resulted in less deviant behavior for both 1st- and 2nd-grade Ss, similar training with the self-verbalized redirective instruction resulted in reduced deviant behavior only among the 2nd graders. In direct contrast, for the 1st graders, training with the redirective self-verbalization resulted in increased levels of deviant behavior. (6 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)