Relationship of posture and age to urinary protein excretion.

The influence of posture and age on urinary protein excretion was studied in 120 normal men volunteers. The supine excretion rate was less than 140 mug/min in all but two people (median value 38 mug/min) and tended to increase with age. The excretion rate decreased on quiet standing in 80% of people, which corresponded to a fall in creatinine-clearance. In the remaining 20% protein excretion increased on standing but generally remained within normal limits and was dissociated from changes in creatinine clearances. This increase was more prevalent in younger people and may represent a phenomenon analogous to orthostatic proteinuria, differing only quantitatively.     

Cholecystokinin-octapeptide suppresses stress-induced eating by inducing hyperglycemia

Intracerebroventricular administration of cholecystokinin-octapeptide (CCK-8) in unanesthetized, unrestrained rats suppressed stress-induced eating and produced hyperglycemia. Prior adrenalectomy markedly reduced the hyperglycemia effect of intraventricular CCK-8 and also decreased the suppressive effect of CCK-8 on stress-induced eating. Our data are compatible with the anorectic effect of CCK-8 being secondary to the hyperglycemia it produces.     

Intersegmental interneurons serving larval and pupal mechanosensory reflexes in the moth Manduca sexta

1. Intersegmental interneurons (INs) that participate in the larval bending reflex and the pupal gin trap closure reflex were identified in the isolated ventral nerve cord of Manduca sexta. INs 305, 504, and 703 show qualitatively different responses in the pupa than in the larva to electrical stimulation of sensory neurons that are retained during the larval-pupal transition to serve both reflexes. Action potentials produced by current injected into the 3 interneurons excite motor neurons that are directly involved in the larval and pupal reflexes. The excitation of the motor neurons is not associated with EPSPs at a fixed latency following action potentials in the interneurons, and thus there do not seem to be direct synaptic connections between the interneurons and the motor neurons. 2. IN 305 (Fig. 2) has a lateral soma, processes in most of the dorsal neuropil ipsilateral to the soma, and a crossing neurite that gives rise to a single contralateral descending axon. IN 305 is excited by stimulation of the sensory nerve ipsilateral to its soma in the larva and the pupa. Stimulation of the sensory nerve contralateral to its soma produces an inhibitory response in the larva, but a mixed excitatory/inhibitory response to the identical stimulus in the pupa. 3. IN 504 (Fig. 3) has a lateral soma, processes throughout most of the neuropil ipsilateral to the soma, and a crossing neurite that bifurcates to give rise to a process extending to the caudal limit of the neuropil and an ascending axon. IN 504 is excited by stimulation of the sensory nerve ipsilateral to its soma in both larvae and pupae, while the response to stimulation of the sensory nerve contralateral to its soma is inhibitory in the larva but mixed (excitatory/inhibitory) in the pupa. 4. IN 703 has a large antero-lateral soma, a neurite that extends across to the contralateral side giving rise to processes located primarily dorsally in both ipsilateral and contralateral neuropils, and two axons that ascend and descend in the connectives contralateral to the soma (Fig. 4). IN 703 responds to stimulation of the sensory nerves on either side of the ganglion, but the form of the response changes during the larval-pupal transition. In the larva, the response consists of very phasic (0-2 spikes) excitation, but in the pupa there is a prolonged excitation that greatly outlasts the stimulus (Fig. 6).(ABSTRACT TRUNCATED AT 400 WORDS)     

Brain-derived neurotrophic factor in the hypothalamic paraventricular nucleus reduces energy intake

Recent studies show that brain-derived neurotrophic factor (BDNF) decreases feeding and body weight after peripheral and ventricular administration. BDNF mRNA and protein, and its receptor tyrosine kinase B (TrkB) are widely distributed in the hypothalamus and other brain regions. However, there are few reports on specific brain sites of actions for BDNF. We evaluated the effect of BDNF in the hypothalamic paraventricular nucleus (PVN) on feeding. BDNF injected unilaterally or bilaterally into the PVN of food-deprived and nondeprived rats significantly decreased feeding and body weight gain within the 0- to 24-h and 24- to 48-h postinjection intervals. Effective doses producing inhibition of feeding behavior did not establish a conditioned taste aversion. PVN BDNF significantly decreased PVN neuropeptide Y (NPY)-induced feeding at 1, 2, and 4 h following injection. BDNF administration in the PVN abolished food-restriction-induced NPY gene expression in the hypothalamic arcuate nucleus. In conclusion, BDNF in the PVN significantly decreases food intake and body weight gain, suggesting that the PVN is an important site of action for BDNF in its effects on energy metabolism. Furthermore, BDNF appears to interact with NPY in its anorectic actions, although a direct effect on NPY remains to be established.     

Recovery of human mesenchymal stem cells following dehydration and rehydration

As cell therapies advance from research laboratories to clinical application, there is the need to transport cells and tissues across long distances while maintaining cell viability and function. Currently cells are successfully stored and shipped under liquid nitrogen vapor. The ability to store these cells in the desiccated state at ambient temperature would provide tremendous economic and practical advantage. Human mesenchymal stem cells (hMSCs) have broad potential uses in tissue engineering and regeneration since they can differentiate along multiple lineages and support hematopoeisis. The current research applied recent technological advances in the dehydration and storage of human fibroblasts to hMSCs. Three conditions were tested: air-dried, air-dried and stored under vacuum (vacuum only), and incubated with 50 mM trehalose + 3% glycerol and then air-dried and stored under vacuum (vacuum + trehalose). Plates containing dehydrated hMSCs were shipped from San Diego to Baltimore overnight in separate FedEx cardboard boxes. The hMSCs were rehydrated with 3 ml of hMSC medium and were able to regain their spindle-shaped morphology and adhesive capability. In addition, they maintained high viability and proliferation capacity. Rehydrated and passaged cells continued to express the characteristic hMSC surface antigen panel. Additionally, cells showed constitutive levels of mRNA for a stromal factor and, when exposed to reagents known to induce differentiation, demonstrated upregulation of two tissue-specific messages indicative of differentiation potential for fat and bone. While our preliminary findings are encouraging, we still need to address consistency and duration of storage by considering factors such as cell water content, oxygen concentration, and the presence of free radicals.     

Light/dark labeling differences in chloroplast membrane polypeptides associated with chloroplast coupling factor o.

The fluorogenic reagent fluorescamine has been used to determine the labeling patterns of Type C spinach chloroplast membrane polypeptides. Membrane polypeptides labeled with fluorescamine were detected by scanning high resolution sodium dodecyl sulfate polyacrylamide gradient slab gels for fluorescence emission. Three membrane polypeptides show a decrease in the extent of labeling when chloroplast membranes are labeled in the light compared to when they are labeled in the dark. These polypeptides have apparent molecular weights 0f 32 000, 23 000 and 15 000. The decrease in labeling observed in the light is abolished or reduced by treatments which inactivate the light-generated transmembrane pH gradient. CF1-depleted chloroplasts show neither a light-activated pH gradient nor a light/dark difference in labeling of these three polypeptides. Both a light-activated pH gradient and light/dark difference in labeling are observed in CF1-depleted chloroplasts which have been treated with N,N'-dicyclohexylcarbodiimide. The same ammonium sulfate fractions of a 2% sodium cholate extract, which are believed to be enriched in the membrane-bound sector of the chloroplast ATPase (CFo) are also found to be enriched in the 32 000, 23 000 and 15 000 molecular weight polypeptides. The three polypeptides are believed to be components of CFo, and the light/dark labeling differences may indicate conformational changes within CFo. Such conformational changes may reflect a mechanism which couples light-generated proton gradients to ATP synthesis.     

Peptic ulcers and erosions are common in Israeli children undergoing upper endoscopy

Background: Peptic ulcers and erosions (PU&E) are thought to be uncommon in children. Patients with early exposure to Helicobacter pylori may be at a higher risk for early onset PU&E. Children in Israel have a high prevalence and early acquisition of Helicobacter pylori (H. pylori) and have easy access to pediatric gastroenterologists and endoscopy. Our aim was to describe the prevalence and characteristics of PU&E in this population referred by Pediatric Gastroenterologists for an upper endoscopy. Methods: We conducted a retrospective study over the years January 2003–May 2006. Over these years we had information on 751 diagnostic upper endoscopies. PU&E was regarded as erosive gastritis/duodenitis or ulcer in either the stomach or duodenum. H. pylori status was assessed using rapid urease test and gastric biopsies. Results: PU&E was detected in 169 (22.5%) patients (ulcers 51 (6.8%), erosions 118 (15.7%)). One hundred twenty‐four had gastric PU&E and 58 had duodenal PU&E. H. pylori was positive in 112 (66.3%). H. pylori‐associated PU&E becomes common after age 10 years, with gastric PU&E presenting much earlier than duodenal disease. Most of the H. pylori‐negative PU&E were idiopathic and improved symptomatically on PPI treatment. Interestingly, 43% of patients with PU&E in our cohort were either immigrants from the former Soviet Union or of Israeli Arab origin. Conclusions: PU&E appears to be common in this selected population with a relatively high incidence of gastric PU&E. H. pylori associated PU&E becomes common after age 10 years with gastric PU&E presenting much earlier than duodenal disease. Non H. pylori PU&E in children comprises approximately a third of all PU&E, are mostly idiopathic and appear earlier than H. pylori associated PU&E.     

The diheme cytochrome c peroxidase from Shewanella oneidensis requires reductive activation

We report the characterization of the diheme cytochrome c peroxidase (CcP) from Shewanella oneidensis (So) using UV-visible absorbance, electron paramagnetic resonance spectroscopy, and Michaelis-Menten kinetics. While sequence alignment with other bacterial diheme cytochrome c peroxidases suggests that So CcP may be active in the as-isolated state, we find that So CcP requires reductive activation for full activity, similar to the case for the canonical Pseudomonas type of bacterial CcP enzyme. Peroxide turnover initiated with oxidized So CcP shows a distinct lag phase, which we interpret as reductive activation in situ. A simple kinetic model is sufficient to recapitulate the lag-phase behavior of the progress curves and separate the contributions of reductive activation and peroxide turnover. The rates of catalysis and activation differ between MBP fusion and tag-free So CcP and also depend on the identity of the electron donor. Combined with Michaelis-Menten analysis, these data suggest that So CcP can accommodate electron donor binding in several possible orientations and that the presence of the MBP tag affects the availability of certain binding sites. To further investigate the structural basis of reductive activation in So CcP, we introduced mutations into two different regions of the protein that have been suggested to be important for reductive activation in homologous bacterial CcPs. Mutations in a flexible loop region neighboring the low-potential heme significantly increased the activation rate, confirming the importance of flexible loop regions of the protein in converting the inactive, as-isolated enzyme into the activated form.     

Computational models for neurogenic gene expression in the Drosophila embryo

The early Drosophila embryo is emerging as a premiere model system for the computational analysis of gene regulation in development because most of the genes, and many of the associated regulatory DNAs, that control segmentation and gastrulation are known. The comprehensive elucidation of Drosophila gene networks provides an unprecedented opportunity to apply quantitative models to metazoan enhancers that govern complex patterns of gene expression during development. Models based on the fractional occupancy of defined DNA binding sites have been used to describe the regulation of the lac operon in E. coli and the lysis/lysogeny switch of phage lambda. Here, we apply similar models to enhancers regulated by the Dorsal gradient in the ventral neurogenic ectoderm (vNE) of the early Drosophila embryo. Quantitative models based on the fractional occupancy of Dorsal, Twist, and Snail binding sites raise the possibility that cooperative interactions among these regulatory proteins mediate subtle differences in the vNE expression patterns. Variations in cooperativity may be attributed to differences in the detailed linkage of Dorsal, Twist, and Snail binding sites in vNE enhancers. We propose that binding site occupancy is the key rate-limiting step for establishing localized patterns of gene expression in the early Drosophila embryo.     

Social Determinants and the Classification of Disease: Descriptive Epidemiology of Selected Socially Mediated Disease Constellations

Background

Most major diseases have important social determinants. In this context, classification of disease based on etiologic or anatomic criteria may be neither mutually exclusive nor optimal.

Methods and Findings

Units of analysis comprised large metropolitan central and fringe metropolitan counties with reliable mortality rates – (n = 416). Participants included infants and adults ages 25 to 64 years with selected causes of death (1999 to 2006). Exposures included that residential segregation and race-specific social deprivation variables. Main outcome measures were obtained via principal components analyses with an orthogonal rotation to identify a common factor. To discern whether the common factor was socially mediated, negative binomial multiple regression models were developed for which the dependent variable was the common factor. Results showed that infant deaths, mortality from assault, and malignant neoplasm of the trachea, bronchus and lung formed a common factor for race-gender groups (black/white and men/women). Regression analyses showed statistically significant, positive associations between low socio-economic status for all race-gender groups and this common factor.

Conclusions

Between 1999 and 2006, deaths classified as “assault” and “lung cancer”, as well as “infant mortality” formed a socially mediated factor detectable in population but not individual data. Despite limitations related to death certificate data, the results contribute important information to the formulation of several hypotheses: (a) disease classifications based on anatomic or etiologic criteria fail to account for social determinants; (b) social forces produce demographically and possibly geographically distinct population-based disease constellations; and (c) the individual components of population-based disease constellations (e.g., lung cancer) are phenotypically comparable from one population to another but genotypically different, in part, because of socially mediated epigenetic variations. Additional research may produce new taxonomies that unify social determinants with anatomic and/or etiologic determinants. This may lead to improved medical management of individuals and populations.