Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

High levels of salt promote urinary calcium (UCa) loss and have the potential to cause bone mineral deficits if intestinal Ca absorption does not compensate for these losses. To determine the effect of excess dietary salt on the osteopenia that follows skeletal unloading, we used a spaceflight model that unloads the hindlimbs of 200-g rats by tail suspension (S). Rats were studied for 2 wk on diets containing high salt (4 and 8%) and normal calcium (0.45%) and for 4 wk on diets containing 8% salt (HiNa) and 0.2% C (LoCa). Final body weights were 9-11% lower in S than in control rats (C) in both experiments, reflecting lower growth rates in S than in C during pair feeding. UCa represented 12% of dietary Ca on HiNa diets and was twofold higher in S than in C transiently during unloading. Net intestinal Ca absorption was consistently 11-18% lower in S than in C. Serum 1,25-dihydroxyvitamin D was unaffected by either LoCa or HiNa diets in S but was increased by LoCa and HiNa diets in C. Despite depressed intestinal Ca absorption in S and a sluggish response of the Ca endocrine system to HiNa diets, UCa loss did not appear to affect the osteopenia induced by unloading. Although any deficit in bone mineral content from HiNa diets may have been too small to detect or the duration of the study too short to manifest, there were clear differences in Ca metabolism from control levels in the response of the spaceflight model to HiNa diets, indicated by depression of intestinal Ca absorption and its regulatory hormone.
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PMID:Effect of excess dietary salt on calcium metabolism and bone mineral in a spaceflight rat model. 771 46

A major goal of neuroscience is to identify the neural and cellular mechanisms of behavior and its plasticity. Progress toward this goal has come particularly from work with a small number of tractable model preparations. One of these is the simple neuromuscular circuit consisting of the accessory radula closer (ARC) muscle of the mollusk Aplysia californica and its innervating motor and modulatory neurons. Contraction of the ARC muscle underlies a component of Aplysia feeding behavior, and plasticity of the behavior is in large part due to modulation of the amplitude and duration of the contractions of the muscle by a variety of modulatory neurotransmitters and peptide cotransmitters, among them the small cardioactive peptides (SCPs), myomodulins (MMs), and serotonin (5-HT). We have studied single dissociated ARC muscle fibers in order to determine whether modulation of membrane ion currents in the muscle might underlie these effects. First, we confirmed that the dissociated fibers were functionally intact: just as with the whole ARC muscle, their contractions were potentiated by 5-HT and SCPB and potentiated as well as depressed by MMA, and their cAMP content was greatly elevated by 5-HT, SCPA and SCPB, and to a lesser extent by MMA and MMB. Next, using voltage-clamp techniques, we found that two ion currents present in the fibers were indeed modulated. The fibers possess a dihydropyridine-sensitive, high-threshold "L"-type Ca current. This current was enhanced by the modulators that potentiate ARC-muscle contractions--5-HT, SCPA and SCPB, and MMA and MMB--but not by buccalinA, a modulator that does not act directly on the ARC muscle. All of the potentiating modulators, as well as elevation of cAMP in the fibers by forskolin or a cAMP analog, maximally enhanced the current about twofold and mutually occluded each other's effects. Since the Ca current supplies Ca2+ necessary for contraction of the muscle, the enhancement of the current is a good candidate to be a major mechanism of the potentiation of the contractions. In the following article we report that the modulators also, to different degrees, activate a distinctive K current and thereby depress the contractions. Net potentiation or depression then depends on the balance between the relative strengths of the modulation of the two ion currents.
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PMID:Enhancement of Ca current in the accessory radula closer muscle of Aplysia californica by neuromodulators that potentiate its contractions. 791 22

Respiratory distress syndrome (RDS) is characterized by the presence of fibrin-rich exudates in the alveoli. Fibrin and its degradation products may play an important role in the pathogenesis of bronchopulmonary dysplasia (BPD). The purpose of this study was to test the hypothesis that preterm neonates with RDS have depressed alveolar fibrinolytic activity and that those with RDS progressing to BPD have an even greater impairment in alveolar fibrinolysis. Serial tracheal aspirate (TA) samples from intubated neonates--9 control and 46 with RDS--were analyzed for fibrinolytic activity. In neonates with RDS, 26 resolved, 18 progressed to BPD, and 2 died before 28 d. Plasminogen activator (PA) and its inhibitor (PAI) were identified in TA by reverse fibrin autography and immunoblotting. Net PA/plasmin activity in TA was significantly depressed on d 1 of life in patients with self-resolved RDS (median = 20.85 ng/mL, p < 0.05) and RDS progressing to BPD (median = 4.97 ng/mL, p < 0.001) compared with control patients (median = 87.1 ng/mL). In addition, neonates progressing to BPD had significantly lower PA/plasmin activity on day one of life compared with neonates with self-resolved RDS (p < 0.001). ELISA for specific PA and PAI were not significantly different. We speculate that depressed fibrinolytic activity may place preterm neonates at risk for RDS and that the degree of this depression may predict the progression to BPD. In infants < or = 30 wk of gestation at birth with RDS, a PA/plasmin activity < or = 10.0 ng/mL on the 1st d of life had a positive predictive value of 80% (12/15) and a negative predictive value of 82% (9/11) for the progression to BPD.
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PMID:Plasminogen activator activity in preterm infants with respiratory distress syndrome: relationship to the development of bronchopulmonary dysplasia. 882 92

5-Hydroxytryptamine(1A) (5-HT(1A)) receptors, which activate inhibitory G-proteins, are implicated in psychiatric disorders including anxiety and depression. Studies suggest that chronic 5-HT(1A) receptor agonist administration alters 5-HT(1A) receptor function, but the effect of chronic treatment on 5-HT(1A) receptor-activated G-proteins is unclear. In this study, agonist-stimulated [35S]guanylyl-5'-O-(gamma-thio)-triphosphate (GTPgammaS) binding was examined following chronic administration of buspirone. Brains were processed for [35S]GTPgammaS autoradiography using R(+)-8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) for 5-HT(1A) receptors or baclofen for GABA(B) receptors. Net 8-OH-DPAT-stimulated [35S]GTPgammaS binding was decreased by 25-30% in the septum and dorsal raphe nucleus of buspirone-treated animals. No significant changes in 8-OH-DPAT-stimulated [35S]GTPgammaS binding were found in the prefrontal, entorhinal or cingulate cortices or hippocampus in buspirone-treated rats. GABA(B) receptor-stimulated [35S]GTPgammaS binding was increased by 25% in the hippocampus, with no significant changes in any other region examined. These results demonstrate region-specific alterations in 5-HT(1A) and GABA(B) receptor-activated G-proteins following chronic buspirone treatment, which may contribute to the clinical effects of this drug.
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PMID:Region-specific changes in 5-HT(1A) receptor-activated G-proteins in rat brain following chronic buspirone. 1068 78

In this era of rapid change, people need to be helped through the grieving process at work. "By acknowledging and articulating what is involved, you facilitate people's movement through it ... successful people in growing organizations need to learn to move through the process as quickly and efficiently as possible and help others do the same." Morris Shectman, in Working Without a Net says, "Contrary to the old paradigm--which held that others don't have a right to know about your personal life--the new paradigm says that it's a necessity that they know." If people are to move through the grief that is caused by undesired change, they will have to tell some of their personal feelings. "Each stage of the process--shock and denial, anger, bargaining, depression, and acceptance--is functional ... when people go through the process in a healthy manner, they'll recycle through it in a diluted fashion." Leaders in the organization can help people start the process or move through it if they get stuck at a particular stage.
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PMID:The grief involved in change. 1078 5

Annual gross productivity of the lichen-dominated cryptoendolithic community was calculated from a computer analysis of photosynthetic response based on laboratory measurements of CO2 exchange and three years (1985-1988) of field nanoclimate data. Photosynthetic optimum increased from -3 to 2 degrees C between irradiance levels of 100 and 1500 micromoles photons m-2 s-1, while the upper compensation point rose from 1 to 17 degrees C. The mean yearly total time available for metabolic activity (temperature above -10 degrees C and moisture present) was 771.3 h for horizontal rock, 421.5 h for northeast-oriented sloped rock, and 1042.2 h for a small depression in horizontal rock (the characteristic site of occasional lichen apothecia). The calculated mean gross productivity value for a horizontal rock was 1215 mg C m-2 y-1, and net photosynthetic gain was 606 mg C m-2 y-1. Net ecosystem productivity (annual accretion of cellular biomass) estimated from long-term events amounted to only about 3 mg C m-2 y-1. The difference between these two values may represent the long-term metabolic costs of the frequent dehydration-rehydration and freezing-thawing cycles or of overwintering, and may account for the leaching of organic substances to the rock. The yearly gross productivity of the cryptoendolithic microbial community of the entire Ross Desert area was estimated at approximately 120,000-180,000 kg C. Of this, 600-900 kg C is in microbial biomass, and much of the rest is soluble compounds that leach into the rocks and possibly percolate to the valleys, providing a source of organic matter for lakes, rivers, and soils.
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PMID:Long-term productivity in the cryptoendolithic microbial community of the Ross Desert, Antarctica. 1153 55

The Indian government's plan to introduce the new long-acting contraceptive Norplant in the National Family Planning Program under pressure from the US government is opposed because Norplant has not been adequately tested. The government has reduced the funding for the national program for eradication of malaria and tuberculosis, but it is proposing to finance a Norplant based population project for the State of Uttar Pradesh. The powers that can turn a deaf ear to the possible hazards of Norplant. Implanted in the arm of a woman, the chemical is released into the bloodstream providing contraception for 5 years. Severe adverse reactions include depression, heart disease thromboembolism, high blood pressure, and ovarian cysts. Many such long-acting contraceptives are being developed including injectables, vaccines, nasal sprays, and vaginal rings with potential permanent impairment to fertility. One of the major objectives of the Family Planning Program is the improvement of the health status of women, but the introduction of Norplant would harm healthy young women. Therefore, the group Saheli and others in the campaign demand: 1) that plans for introduction of Norplant in the Family Planning Program be halted immediately; 2) that the introduction of any other long acting invasive contraceptive such as Net-En, vaginal ring, nasal spray, and anti-fertility vaccine be banned, both on the grounds of inadequacy of the health services and loss of user controls; 3) that information on the safety aspects of Norplant and the basis on which the Drugs Controller has granted his approval be made public; 4) that each and every one of the hundreds of women who still have the implant should be located, and the implant removed; and 5) that all hormonal contraceptive preparations be banned in the social marketing program as their use involves extensive monitoring.
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PMID:Norplant campaign in India. 1228 26

High midday temperatures can depress net photosynthesis. We investigated possible mechanisms underlying this phenomenon in leaves of Eperua grandiflora (Aubl.) Benth. saplings. This tropical tree establishes in small gaps in the rainforest canopy where direct sunlight can raise midday temperatures markedly. We simulated this microclimate in a growth chamber by varying air temperature between 28 and 38 degrees C at constant vapor pressure. A decrease in stomatal conductance in response to an increase in leaf-to-air vapor pressure difference (deltaW) caused by an increase in leaf temperature (Tleaf) was the principal reason for the decrease in net photosynthesis between 28 and 33 degrees C. Net photosynthesis decreased further between 33 and 38 degrees C. Direct effects on mesophyll functioning and indirect effects through deltaW were of similar magnitude in this temperature range. Mitochondrial respiration during photosynthesis was insensitive to Tleaf over the investigated temperature range; it thus did not contribute to midday depression of net photosynthesis. Internal conductance for CO2 diffusion in the leaf, estimated by combined gas exchange and chlorophyll fluorescence measurements, decreased slightly with increasing Tleaf. However, the decrease in photosynthetic rate with increasing Tleaf was larger and thus the difference in CO2 partial pressure between the substomatal cavity and chloroplast was smaller, leading to the conclusion that this factor was not causally involved in midday depression. Carboxylation capacity inferred from the CO2 response of photosynthesis increased between 28 and 33 degrees C, but remained unchanged between 33 and 38 degrees C. Increased oxygenation of ribulose-1,5-bisphosphate relative to its carboxylation and the concomitant increase in photorespiration with increasing Tleaf were thus not compensated by an increase in carboxylation capacity over the higher temperature range. This was the principal reason for the negative effect of high midday temperatures on mesophyll functioning.
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PMID:Midday depression of net photosynthesis in the tropical rainforest tree Eperua grandiflora: contributions of stomatal and internal conductances, respiration and Rubisco functioning. 1295 80

Photosynthetic light and temperature response curves were measured seasonally in seedlings of white spruce (Picea glauca (Moench.) Voss) grown for two years in the understory of aspen (Populus tremuloides Michx.) or in the open in central Alberta. Light-saturated rate of net photosynthesis, the optimum temperature for net photosynthesis, transpiration rate, photochemical efficiency, and stomatal and mesophyll conductances increased from spring to summer and declined thereafter, whereas dark respiration rate and compensation and saturation points were highest in spring. Depression of photosynthetic parameters was greater in open-grown seedlings than in understory seedlings during the periods in spring and autumn when night frosts were common. Net photosynthetic rates were similar in understory and open-grown seedlings in summer, but they were significantly lower in open-grown seedlings in spring and autumn. Significantly lower transpiration rates and stomatal conductances in open-grown seedlings than in understory seedlings were also observed at 15 and 25 degrees C in the autumn. Shoot and needle growth were less in open-grown seedlings than in understory seedlings. In summer, when irradiances were low in the aspen understory, understory white spruce seedlings maintained a positive carbon balance by decreasing their compensation and saturation points and increasing their photochemical efficiency compared to spring and autumn.
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PMID:Seasonal photosynthetic responses to light and temperature in white spruce (Picea glauca) seedlings planted under an aspen (Populus tremuloides) canopy and in the open. 1475 35

The new psychological disorder of Internet addiction is fast accruing both popular and professional recognition. Past studies have indicated that some patterns of Internet use are associated with loneliness, shyness, anxiety, depression, and self-consciousness, but there appears to be little consensus about Internet addiction disorder. This exploratory study attempted to examine the potential influences of personality variables, such as shyness and locus of control, online experiences, and demographics on Internet addiction. Data were gathered from a convenient sample using a combination of online and offline methods. The respondents comprised 722 Internet users mostly from the Net-generation. Results indicated that the higher the tendency of one being addicted to the Internet, the shyer the person is, the less faith the person has, the firmer belief the person holds in the irresistible power of others, and the higher trust the person places on chance in determining his or her own course of life. People who are addicted to the Internet make intense and frequent use of it both in terms of days per week and in length of each session, especially for online communication via e-mail, ICQ, chat rooms, newsgroups, and online games. Furthermore, full-time students are more likely to be addicted to the Internet, as they are considered high-risk for problems because of free and unlimited access and flexible time schedules. Implications to help professionals and student affairs policy makers are addressed.
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PMID:Shyness and locus of control as predictors of internet addiction and internet use. 1566 51


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