Search

It is difficult for rats to learn to go to an arm of a T-maze to receive food that is dependent on the time of day, unless the amount of food in each daily session is different. In the same task, rats show evidence of time-place discriminations if they are required to press levers in the arms of the T-maze, but learning is only evident when the first lever press is considered, and not the first arm visited. These data suggest that rats struggle to use time as a discriminative stimulus unless the rewards/events differ in some dimension, or unless the goal locations can be visited prior to making a response. If both of these conditions are met in the same task, it might be possible to compare time-place learning in two different measures that essentially indicate performance before and after entering the arms of the T-maze. In the present study, we investigated time-place learning in rats with a levered T-maze task in which the amounts of food varied depending on the time of day. The first arm choices and first lever presses both indicated that the rats had acquired time-place discriminations, and both of these measures became significantly different from chance during the same block. However, there were subtle differences between the two measures, which suggest that time-place discrimination is aided by visiting the goal locations.

The time-course and extent of visible particle (VP) and sub-visible particle (SVP) formation was monitored as a function of interfacial area (IA) for a model bioconjugate. To facilitate particle formation, the bioconjugate was agitated in a glass vial and exposed to IAs up to 478 mm 2 . Since vials had equal fill and headspace volumes, the area of the air-water interface was varied by placing vials on angled blocks at 0°, 30°, 60°, or 90° from the horizontal. A significant increase in visible and sub-visible particle formation was observed with increasing air-water IA. Exposure to IAs below ∼305 mm 2 resulted in the formation of very few particles, while IAs > ∼305 mm 2 resulted in substantial particle formation. Visible and sub-visible particle morphology varied with interfacial area and time. The sub-visible particles initially increased with time but did not reach steady state; instead the initial increase was followed by complete depletion. These phenomena indicate that visible particle formation likely increased at the expense of the sub-visible particle population and demonstrate a potential link between the two particle populations for this model bioconjugate. Initiation of particle formation did not result in corresponding decreases in protein concentration or increases in soluble aggregates. However, extended agitation time resulted in a significant decrease in protein concentration.

It can be difficult to differentiate acute heart failure syndrome (AHFS) from other causes of acute dyspnea, especially when patients present in extremis. The objective of the study was to determine the predictive value of physical examination findings for pulmonary edema and elevated B-type natriuretic peptide (BNP) levels in patients with suspected AHFS. This was a secondary analysis of a previously reported prospective study of jugular vein ultrasonography in patients with suspected AHFS. Charts were reviewed for physical examination findings, which were then compared to pulmonary edema on chest radiography (CXR) read by radiologists blinded to clinical information and BNP levels measured at presentation. The predictive value of every sign and combination of signs for pulmonary edema on CXR or an elevated BNP was poor. Since physical examination findings alone are not predictive of pulmonary edema or an elevated BNP, clinicians should have a low threshold for using CXR or BNP in clinical evaluation. This brief research report suggests that no physical examination finding or constellation of findings can be used to reliably predict pulmonary edema or an elevated BNP in patients with suspected AHFS.

The freeze-drying behavior of three model proteins, namely, lysozyme, BSA, and IgG, has been studied using a variety of techniques under two different primary drying conditions (shelf temperatures of -25°C and +25°C, respectively) in an amorphous formulation. Manometric temperature measurements were used to characterize product temperature (T (pr)), sublimation rates, and product resistance (R (p)) during primary drying. Biophysical techniques such as circular dichroism, fluorescence, and Fourier transform infrared spectroscopy were used to study protein conformation. Size exclusion chromatography was used to monitor the formation of high-molecular-weight species (HMWS) over time on storage, and cake morphology was studied using scanning electron microscopy. The differences in the freeze-drying behavior of the three proteins were more evident at higher protein concentrations, where the protein significantly influences the behavior of the formulation matrix. However, these differences were minimized in the aggressive mode and were insignificant at lower protein concentrations where excipients dominated the freeze-drying behavior. Differences in cake morphology were observed between the two drying conditions employed as well as between the three proteins studied. The stability and the protein structure, however, were equivalent for the protein cakes generated using the two different primary drying conditions.

Background and Objectives: Older African Americans are often under diagnosed and under treated for depression. Given that older African Americans are more likely than whites to identify spirituality as important in depression care, we sought to understand how spirituality may play a role in the way they conceptualize and deal with depression in order to inform possible interventions aimed at improving the acceptability and effectiveness of depression treatment., Design: Cross-sectional qualitative interview study of older African American primary care patients., Participants and Setting: Forty-seven older African American patients recruited from primary care practices in the Baltimore, MD area, interviewed in their homes., Measurements: Semi-structured interviews lasting approximately 60 minutes. Interviews were transcribed and themes related to spirituality in the context of discussing depression were identified using a grounded-theory approach., Main Results: Participants in this study held a faith-based explanatory model of depression with a particular emphasis on the cause of depression and what to do about it. Specifically, participants described depression as being due to a "loss of faith" and faith and spiritual/religious activities were thought to be empowering in the way they can work together with medical treatments to provide the strength for healing to occur., Conclusions: The older African Americans in this study described an intrinsically spiritual explanatory model of depression. Addressing spirituality in the clinical encounter may lead to improved detection of depression and treatments that are more congruent with patient's beliefs and values.

Background: A number of instruments have been developed for investigating relationships between spirituality and health, and have been used to assess spirituality in African-Americans. Yet, the cultural appropriateness for African-Americans of these instruments has not been investigated to date., Objectives: To evaluate the construct validity and reliability of spirituality measures used in health research from 1982 to 2005., Method: Systematic review of the literature., Results: Thirty five studies and five measures of spirituality met the inclusion criteria. Most of the spirituality measures were developed in primarily Caucasian-American samples. African-Americans were represented in 71% of the studies (n = 25) using spirituality measures in health research. Distinct cultural attributes of African-American spirituality were omitted in most of the spirituality measures. Two studies were retrieved in which psychometric evaluation was conducted in entirely African-American samples., Discussion: Spirituality is a significant cultural experience and belief that influences the health behaviors of African-Americans. The lack of a culturally appropriate measure of African-American spirituality is a major limitation of studies investigating spirituality and health in this population. Development of a culturally appropriate and sensitive measure of spirituality in African-Americans is suggested to strengthen the quality of research in this area.

X-ray absorption spectroscopy has been used to compare the metal coordination of the N-terminal zinc binding domain of eukaryal human transcription factor (TF) IIB to the previously reported structure of archaeal Pyrococcus furiosus (Pf) TFB. Full length and N-terminal fragments for both PfTFB and human TFIIB were cloned, expressed, and purified. The [C10H] variant of PfTFB was constructed to resemble the metal binding motif of higher eukaryal TFIIB proteins by mutating the second cysteine ligand to a histidine. All five proteins bind zinc in a 1:1 ratio. Zn X-ray absorption spectroscopy of human TFIIB and [C10H]PfTFB mutant are consistent with ZnS3(N,O) ligation, and further suggest that the N/O ligand is an imidazole.