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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The authors analyzed the results of a multihospital collaborative study on the effectiveness of lithium prophylaxis in recurrent depression in terms of dosage and found that serum lithium levels between 0.5 and 0.7 mEq/liter and doses below 1000 mg/day were relatively ineffective in preventing recurrences. Serum lithium levels between 0.8 and 1.0 mEq/liter and doses above 1000 mg/day were associated with a relatively low failure rate. The authors discuss the relevance of these findings to current prescription guidelines for lithium carbonate.
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PMID:Relationship between dosage and response to lithium prophylaxis in recurrent depression. 126 63

The mechanism of inhibition of HCO3 transport by parathyroid hormone (PTH) in the proximal tubule is not clearly defined. Previous studies in vitro have suggested that this effect is mediated via cAMP generation, which acts to inhibit Na/H exchange, resulting in cell acidification. To examine this question in vivo, intracellular pH (pHi) was measured in the superficial proximal tubule of the rat using the pH-sensitive fluoroprobes 4-methylumbelliferone (4MU) and 2',7'-bis(carboxyethyl)-(5, and 6)-carboxyfluorescein (BCECF). PTH was found to alkalinize the cell. This alkalinization suggested inhibition of basolateral base exit, which was confirmed by in situ microperfusion studies: lowering HCO3 in peritubular capillaries acidified the cell, an effect blunted by PTH. Removal of luminal Na promoted basolateral base entry, alkalinizing the cell. This response was also blunted by PTH. Readdition of luminal Na stimulated the luminal Na/H exchanger, causing an alkalinization overshoot that was partially inhibited by PTH. cAMP inhibited luminal H secretion but did not alkalinize the cell. Stimulation of phosphatidylinositol-bis-phosphate turnover by PTH was suggested by the effect to the hormone to increase cell Ca. Blocking the PTH-induced rise in cell Ca blunted the effect of the hormone to alkalinize the cell, as did inhibition of phosphatidylinositol breakdown. Furthermore, stimulation of protein kinase C by a phorbol ester and a diacylglycerol applied basolaterally alkalinized the cell and inhibited luminal H secretion. The findings indicate that both arms of the phosphatidylinositol-bis-phosphate cascade play a role in mediating the effect of PTH on the cell pH. The results are consistent with the view that PTH inhibits base exit in the proximal tubule by activation of the phosphatidylinositol cascade. The resulting alkalinization may contribute, with cAMP, to inhibit apical Na/H exchange and the PTH-induced depression of proximal HCO3 reabsorption.
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PMID:Parathyroid hormone decreases HCO3 reabsorption in the rat proximal tubule by stimulating phosphatidylinositol metabolism and inhibiting base exit. 131 50

The catecholamines, adrenaline and noradrenaline, are released into the circulation of fish during a variety of physical and environmental disturbances that share the common feature of a requirement for enhanced blood oxygen transport. Indeed, the dominant factor controlling the mobilization of catecholamines from chromaffin tissue is a depression of blood oxygen content usually coinciding with a reduction of hemoglobin-O2 (Hb-O2) binding to 50-60% saturation. The elevation of plasma catecholamine levels, under such conditions, activates a beta-adrenergic cyclic AMP-dependent Na+/H+ exchanger on the red blood cell (rbc) membrane. The adrenergic responsiveness AMP-dependent Na+/H+ exchanger on the red blood cell (rbc) membrane. The adrenergic responsiveness of the rbc Na+/H+ exchanger to catecholamines varies both within and between species. Such inter- and intra-specific differences may reflect, in part, the availability of cell surface beta-adrenoceptors that are functionally coupled to adenylate cyclase. The activation of rbc Na+/H+ exchange and the accompanying profound adjustments of intracellular and extracellular acid-base status, nucleoside triphosphate (NTP) levels, and cooperativity of Hb-O2 binding have important consequences on both O2 and CO2 transfer and transport in the blood that vary markedly at the sites of oxygenation (the gill) and deoxygenation (the tissues) thereby enabling simultaneous amelioration of O2 loading and unloading. At the gill, oxygen transfer is enhanced owing to increases in Hb-O2 affinity and capacity while at the tissues, oxygen delivery is facilitated by a reduction of Hb-O2 affinity. This reduction in affinity at the tissues is a consequence of the combined effects of increased cooperativity of Hb-O2 binding and a rise in venous PCO2 (PvCO2) caused by the titration of HCO3- by H+ extruded by the rbc Na+/H+ exchanger. This elevation of PvCO2 may contribute to the rise in arterial PCO2 (PaCO2) observed after adrenergic activation of rbc Na+/H+ exchange that is caused primarily by impairment of rbc CO2 excretion related to modification of the intracellular acid-base status.
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PMID:Control and consequences of adrenergic activation of red blood cell Na+/H+ exchange on blood oxygen and carbon dioxide transport in fish. 132 42

The proximal tubule model of this laboratory [Am. J. Physiol. 250 (Renal Fluid Electrolyte Physiol. 19): F860-F873, 1986] has been updated to examine proposed pathways for Cl- transport. Two additional buffer pairs have been added, i.e., HCO2-/H2CO2 and NH3/NH4+. At the luminal cell membrane Cl-/HCO2- and Cl-/HCO3- exchange are considered as pathways for Cl- entry, whereas at the peritubular membrane, Cl- exit occurs by either Na(+)-2HCO3-/Cl- exchange or K(+)-Cl- cotransport. Calculations with this model indicate that absolute proximal reabsorption of both Na+ and Cl- are critically dependent on the rate of luminal Na+/H+ exchange. In contrast, increases in the coefficient for Cl-/HCO2- exchange have little impact on overall Cl- flux, but, by enhancing base secretion, limit the depression of end-proximal HCO3-. Model calculations confirm those of Preisig and Alpern (J. Clin. Invest. 83: 1859-1867, 1989) showing that their measured value of luminal membrane H2CO2 permeability is inadequate to sustain the transcellular Cl- flux as Cl-/HCO2- exchange. Conversely, with sufficiently high H2CO2 permeability, luminal Cl- uptake is enhanced along the tubule, as HCO2- secretion and luminal acidification increase luminal H2CO2 to values severalfold greater than in glomerular filtrate. At the basolateral membrane, the thermodynamic driving force across the Na(+)-2HCO3-/Cl- exchanger is small. Although its contribution to steady-state Cl- exit may be less than the K(+)-Cl- cotransporter, the Na(+)-2HCO3-/Cl- exchanger can be a mechanism by which cytosolic acidification enhances peritubular Cl- transport, when luminal acidification enhances luminal Cl- uptake. A simulation is presented in which impermeant replacement of luminal Na+ leads to enhanced convective Cl- flux across the tight junction and alkalinization of the lateral interspace. In this setting, cytosolic Cl- depletion via the Na(+)-2HCO3-/Cl- exchanger may mimic luminal membrane Na(+)-Cl- cotransport.
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PMID:Chloride transport in a mathematical model of the rat proximal tubule. 144 69

Depression in the elderly is characterized by a prolonged course and resistance to pharmacological treatment. Moreover, in old age sensitivity to the anticholinergic and cardiac side-effects of tricyclic antidepressants (TCA) increases. Recently new antidepressants with fewer side-effects have been developed. Of these, trazodone and mianserin have been particularly recommended for the treatment of depression in older patients. However, the effects of these new compounds on depression are similar to those of the older TCA's, leaving a substantial number of elderly patients with resistant depression. While there are many publications on the potentiation of the effect of TCA's by lithium carbonate, there is little data on the potentiation of the effects of trazodone and of mianserin by lithium, and no reports of their combined use in elderly patients. Birkhimer et al. reported a case of successful treatment of refractory depression with trazodone and lithium in a 45-year-old man. Heninger et al. successfully treated 2 treatment-refractory patients (aged 52 and 58 years, respectively) with a combination of mianserin and lithium. Price et al. reported that 85% of 12 drug-resistant patients improved when treated with lithium and mianserin, but only 22% of 9 patients treated with lithium and trazodone. We report a 73-year-old man with resistant depression whose physical condition contraindicated tricyclic antidepressants, in whom the combination of mianserin and lithium was both safe and effective.
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PMID:[Lithium augmentation for mianserin-resistant depression in the elderly]. 145 97

Until recently it appeared that lithium carbonate possessed a unique spectrum of clinical action in the acute and prophylactic treatment of manic and depressive episodes. It is now increasingly apparent that the anticonvulsants carbamazepine and valproate also share components of this spectrum of efficacy in the affective disorders but, in addition, are clinically effective in some lithium nonresponders. This clinical convergence can now drive a reexamination of the potential mechanisms of action of these compounds in the affective disorders. In spite of intensive study over several decades, the mechanism of action of lithium has remained elusive. A basic conundrum in the consideration of the actions of lithium has also been to explain how a simple ion could have such complex effects on multiple neurotransmitter systems and, in particular, have bimodal actions in the treatment of both manic and depressive phases of the illness. We suggest that a fundamental reconceptualization of both mania and depression as overactivated neural systems (either excitatory or inhibitory) could facilitate this conceptualization. Given the recent evidence linking lithium's effects to uncoupling receptor-mediated activity at the level of G-proteins or attenuating it at the level of second messenger systems mediated by adenylate cyclase or phosphoinositide turnover, these mechanisms become ideal candidates for considering how the drug could dampen overactivated systems potentially relevant to either depression or mania. The lag in onset of maximum therapeutic action of lithium, carbamazepine, and valproate further suggests that biologic effects associated with chronic compared with acute administration are the prime candidates for psychotropic effects. Comparison of the acute and chronic effects of carbamazepine with those of valproate is also offered to focus on the most likely receptor, second-messenger, and ion channel mechanisms involved in their anticonvulsant and psychotropic actions. It is hoped that better understanding of the comparative actions of lithium, carbamazepine, and valproate will allow better targeting of individual drugs for individual patients as well as, ultimately, the development of new and more selective treatments for the recurrent affective disorders.
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PMID:Mechanisms of action of anticonvulsants in affective disorders: comparisons with lithium. 154 15

The effects of once- and twice-daily dosing with lithium carbonate were compared in a non-blind, cross-over study on 20 consecutive patients with mood disorders. Mental status, side effects and target organ function were examined after a minimum of a 1-month treatment with each regimen. Eighteen patients completed the study and 2 withdrew because of side effects. There were no significant differences between the 2 groups on the Hamilton Rating Scale for Depression, the Bech-Rafaelsen Mania Scale, the UKU Side Effects Scale or in serum lithium, electrocardiogram and urine volumes. Most blood tests showed no significant difference between the 2 treatment schedules except for white blood cells, ionized calcium and phosphate concentration. The once-daily regimen was associated with a higher white cell count, increased serum phosphate and elevated serum ionized calcium. We conclude that patients are able to tolerate once-daily dosing with lithium carbonate as well as twice-daily dosing.
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PMID:Lithium treatment: a comparison of once- and twice-daily dosing. 154 52

A 3-day-old Quarter Horse colt was examined because of signs of severe depression, discomfort, and abdominal straining. The foal seemed disoriented, and the abdomen was tense and distended ventrally. The differential diagnoses included ruptured urinary bladder, retained meconium, septicemia/bacteremia, and neonatal maladjustment syndrome. Serum biochemical analysis revealed marked hyponatremia, hypochloremia, and moderate hyperkalemia, as well as mildly high urea, creatinine, and phosphorus concentrations. The primary differential diagnosis at this time was ruptured urinary bladder. Abdominocentesis was performed to confirm this diagnosis. Microscopic examination of abdominal fluid revealed calcium carbonate crystals, which originated from the urine of the foal. Biochemical analysis also confirmed the diagnosis of ruptured urinary bladder, because the ratio of peritoneal fluid creatinine to serum creatinine was 2.8:1. The foal died before surgical correction could be attempted.
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PMID:Diagnosis of ruptured urinary bladder in a foal by the identification of calcium carbonate crystals in the peritoneal fluid. 161 90

The purpose of this study was to ascertain the clinical benefits of long-term antidepressant drug treatment in patients with recurrent major depression. Bibliographic reviews of four textbooks and five review articles, literature searches using MEDLINE (1977-1987) and EXCERPTA MEDICA (1974-1987), hand-searching of the bibliographies of identified papers, and a private set were used for data identification. The most informative, definitive research report was selected using explicit criteria for evaluating study design and quality, of each described, randomized, controlled, double-blind trial of long-term antidepressant agent treatment. The trials were started at a specified period after recovery from an affective episode, in patients with major depression. Of the fifty-five originally identified articles, nine were selected that specifically addressed this purpose. The basic data were extracted in the form of 2 x 2 tables comparing the number of patients with an affective relapse to those remaining well and meta-analysed. Six of the selected trials addressed continuation and three addressed maintenance therapy. In two trials of continuation and in one trial of maintenance treatment, antidepressants were significantly more active than a placebo. In none of the trials were antidepressants inferior to a placebo. Continuation therapy with antidepressants (amitriptyline and imipramine) is effective. There are insufficient data to allow any conclusions about the efficacy of maintenance therapy with antidepressants, long-term treatment with antidepressants relative to that with lithium carbonate, or long-term antidepressant treatment in patients with chronic depression.
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PMID:Continuation and maintenance therapy with antidepressive agents. Meta-analysis of research. 138 62

A 24-year-old newly diagnosed male patient with diabetes presented with diabetic ketoacidosis (DKA) (pH 7.16, HCO3 6.0) and extreme hypertriglyceridemia (239.35 mmol/L). The diagnosis of DKA was delayed because of the apparent depression of the true serum glucose (to 11 mmol/L). He was treated with intravenous (IV) insulin and rehydration, which normalized his pH, HCO3, and triglyceride levels. To the authors' knowledge, this is both the highest triglyceride level recorded and the first report of a high triglyceride level as the apparent cause of a factitiously low glucose level.
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PMID:Pseudonormoglycemia in diabetic ketoacidosis with elevated triglycerides. 189 2


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