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

An influence of early stimulation on sensitivity to acute stress in adulthood has been reported. The purpose of the present work was to determine the effect of exposure of male and female rats to three models of chronic stress (unpredictable stress, cold stress and handling) from day 2 to day 15 of life on behavioral and endocrine sensitivity to chronic stresses in adulthood. The chronic stresses applied in adulthood were a model of intermittent cold stress (daily 30-min sessions at -20 degrees C for 15 days) and the Katz's model of unpredictable chronic stress (15 days). Forced swim behavior and serum concentration of the stress-sensitive hormones, corticosterone and prolactin, were chosen to investigate stress sensitivity. It was found that all neonatal treatments stimulated body weight gain, did not cause infant mortality and did not affect forced swim behavior as adult. The repetitive exposure to cold stress in adulthood did not cause major impairment of forced swim behavior and did not affect basal levels of serum corticosterone and prolactin in either control or experimental rats. These findings support the view that repeated stressors can induce behavioral and endocrine adaptation in rats. The neonatal treatments did not affect this characteristic. The exposure of control rats to the unpredictable stress model severely impaired forced swim behavior and increased basal levels of serum corticosterone and prolactin. This observation conforms to the view that standard laboratory rats cannot adapt to unpredictable chronic stress. This has been reported to cause a behavioral depression syndrome comprising forced swim deficit and endocrine alterations.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Neonatal chronic stress induces subsensitivity to chronic stress in adult rats. I. Effects on forced swim behavior and endocrine responses. 238 47

Because aerobic metabolic rates decrease in hypoxia-sensitive cells under oxygen-limiting conditions, the demand for glucose or glycogen for anaerobic glycolysis may rise drastically as a means of making up for the energetic shortfall. However, ion and electrical potentials typically cannot be sustained because of energy insufficiency and high membrane permeabilities; therefore metabolic and membrane functions in effect become decoupled. In hypoxia-tolerant animals, these problems are resolved through a number of biochemical and physiological mechanisms; of these metabolic arrest and stabilized membrane functions are the most effective strategies for extending tolerance to hypoxia. Metabolic arrest is achieved by means of a reversed or negative Pasteur effect (reduced or unchanging glycolytic flux at reduced O2 availability); and coupling of metabolic and membrane function is achievable, in spite of the lower energy turnover rates, by maintaining membranes of low permeability (probably via reduced densities of ion-specific channels). The possibility of combining metabolic arrest with channel arrest has been recognized as an intervention strategy. To date, the success of this strategy has been minimal, mainly because depression of metabolism through cold is the usual arrest mechanism used, and hypothermia in itself perturbs controlled cell function in most endotherms.
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PMID:Defense strategies against hypoxia and hypothermia. 241 16

Thermal responsiveness of anterior hypothalamic-preoptic (AH-PO) neurons was studied in unanesthetized sleeping cats carrying chronically implanted electrodes and thermistors for recording EEG, EMG and AH-PO temperature. Activity of AH-PO neurons was recorded using tungsten microelectrodes during atraumatic stereotaxic head restraint in a sound-attenuated chamber at 22-25 degrees C. Direct cooling or warning of the AH-PO region was accomplished with bilaterally positioned water-perfused thermodes. 110 thermosensitive neurons (77% cold-sensitive and 23% warm-sensitive) were sampled during wakefulness and synchronized sleep. In contrast, the changes in spontaneous firing rate shown by AH-PO neurons during desynchronized sleep were often associated with a strong depression or outright suppression of their responsiveness to AH-PO thermal stimulation.
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PMID:Polygraphic study of anterior hypothalamic-preoptic neuron thermosensitivity during sleep. 241 86

In hypoxia sensitive cells and tissues, the rates of glucose and O2 consumption are inversely related (Pasteur Effect). Under O2 limiting conditions the demands for glucose (glycogen) in such cells may drastically rise as a means for maintaining ATP turnover close to normoxic rates; nevertheless ion and electrical potentials cannot be sustained due to energy insufficiency and high membrane permeability; metabolic and membrane functions, in effect, are decoupled. 'Good' animal anaerobes resolve these problems with a number of biochemical and physiological mechanisms; of these metabolic arrest and stabilized membrane functions are the most effective strategies for extending hypoxia tolerance. Metabolic arrest is achievable by means of a reversed or negative Pasteur Effect (reduced or unchanging glycolytic flux at reduced O2 availability) while coupling of metabolic and membrane function is achievable in spite of the lower energy turnover rates by maintaining membranes of low permeability (probably via reduced densities of ion-specific channels). Although the strategy of combining metabolic arrest with channel arrest has been recognized as a possible intervention, to date success has been minimal, mainly because cold depression of metabolism is the usual arrest mechanism used and this hypothermia in itself perturbs controlled cell function in most endotherms. The only endothermic systems currently known which appear able to use the dual strategy for extending hypoxia tolerance are hypoperfused hypometabolic tissues and organs of diving marine mammals.
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PMID:Metabolic arrest. 242 20

The effect of two dihydropyridine calcium (Ca) channel blocking drugs on cerebral glucose metabolism (LCGU), blood flow (LCBF), and blood flow-metabolism coupling were studied in thermally injured rat brain using quantitative radioautographic techniques. No reversal of the previously noted LCGU depression caused by the freezing lesion (Pappius, 1981) was detected following treatment with either PY-108-068 (PY) or nimodipine (NIM). These results therefore provided no support for the role of Ca in the mechanism of functional disturbances induced by cold injury (Pappius and Wolfe, 1983b), though they do not rule out its involvement. Treatment with PY, but not NIM, reestablished the normal LCBF-LCGU relationship in cortical areas, which has been shown to be disturbed by the freezing lesion and in subcortical and brainstem structures, in which the alteration caused by the injury was not as pronounced. The results suggest that the mechanism that apparently uncouples LCBF from LCGU in injured brain is altered in the presence of PY. However, since NIM did not have the same effect on LCBF, it is not clear whether the effects of PY relate to blockade of Ca channels or some other effect of PY.
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PMID:Effects of two dihydropyridine calcium channel blockers on cerebral metabolism and blood flow in traumatized rat brain. 243 59

The frequency of anaerobic myocardial metabolism was studied in 14 patients undergoing coronary artery bypass surgery during enflurane-supplemented high-dose fentanyl anesthesia and compared with other clinical monitors of myocardial ischemia including the configuration of the pulmonary capillary wedge pressure (PCWP) and electrocardiographic findings. Hemodynamic parameters, coronary sinus blood flow, myocardial oxygen and lactate extractions, and a seven-lead ECG were recorded before and after cannulation of the aorta and vena cava, during total cardiopulmonary bypass (CPB) in a vented heart, during rewarming after global myocardial ischemia and cold cardioplegia, and 15 minutes after coming off bypass. The cannulation for CPB induced no changes in the central or coronary hemodynamics, but four patients had abnormal lactate metabolism. Two of these also had ST segment depression, and two had prominent AC waves on the PCWP tracing. Coronary sinus blood flow and myocardial oxygen extraction were maintained at the beginning of CPB, but lactate extraction decreased markedly or turned to lactate production, and ECG changes indicating myocardial ischemia were seen in five patients. During rewarming and after CPB, all patients had abnormal lactate metabolism despite decreased myocardial oxygen extraction, adequate coronary perfusion pressure, and adequate coronary sinus blood flow. During these periods most patients also had cardiac conduction disturbances that made the interpretation of the ST segment impossible. Only one patient had clearly abnormal AC and V waves on the PCWP tracing after CPB. Two patients had ECG evidence of a perioperative myocardial infarction, but they had no significant clinical consequences. Four patients had a fascicular block at discharge. These results indicate that anaerobic myocardial metabolism is common during and after CPB, and that associated myocardial ischemia cannot always be reliably detected by changes in the ECG or the PCWP tracings.
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PMID:Myocardial oxygen balance and cardiopulmonary bypass in patients undergoing coronary artery bypass grafting. 252 Jun 56

Twenty-five infants and young children intoxicated by carbamate and organophosphorus compounds are described. Presenting signs and symptoms in children differed from those described in adults and were mainly related to severe CNS depression, coma and stupor, dyspnea, and flaccidity. Other clinical signs such as miosis, excessive salivation and tearing, sweaty, cold skin, and gastrointestinal symptoms were less frequent, while fasciculations and bradycardia were quite uncommon on arrival. Only two patients presented with all typical signs of organophosphate poisoning as described in adults. Signs of carbamate poisoning were indistinguishable from those of organophosphate poisoning and included signs of myoneural and CNS cholinergic receptor involvement, in addition to parasympathetic muscarinic dysfunction. Atropine sulfate was found to have a clear beneficial CNS effect in addition to its known peripheral antimuscarinic effect. Our data suggest that the clinical presentation of carbamate and organophosphate poisoning in early childhood and its response to therapy are quite different from those of adults and older children.
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PMID:Carbamate and organophosphate poisoning in early childhood. 260 93

The availability of isotype-specific antisera for beta-tubulin, coupled with genetic and biochemical analysis, has allowed the determination of beta-tubulin isotype expression and distribution in Chinese hamster ovary (CHO) cells. Using genetic manipulations involving selection for colcemid resistance followed by reversion and reselection for drug resistance, we have succeeded in isolating cell lines that exhibit three major and one minor beta-tubulin spots by two-dimensional gel electrophoresis. In concert with isotype-specific antibodies, analysis of these mutants demonstrates that CHO cells express two copies of isotype I, at least one copy of isotype IV, and very small amounts of isotype V. All three isotypes assemble into both cytoplasmic and spindle microtubules and are similar in their responses to cold, colcemid, and calcium-induced depolymerization. They have comparable turnover rates and are equally sensitive to depression of synthesis upon colchicine treatment. These results suggest that beta-tubulin isotypes are used interchangeably to assemble microtubule structures in CHO cells. However, of 18 colcemid-resistant mutants with a demonstrable alteration in beta-tubulin, all were found to have the alteration in isotype I, thus leaving open the possibility that subtle differences in isotype properties may exist.
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PMID:Expression and function of beta-tubulin isotypes in Chinese hamster ovary cells. 264 75

The present study attempts to delineate the role of hemispheric activation in depression and pain. It was hypothesized that the right hemisphere is specialized to become activated by and to process negative affective stimuli, and that this specialization may play a role in the co-occurrence of depression and pain. The relationship between depression, experimental pain, and cerebral laterality was investigated in 16 depressed and 16 nondepressed, right-handed, female students. Cerebral laterality was measured via tasks assessing visual and auditory biases, and pain was assessed via a cold pressor task. The proposition that the right hemisphere mediates the co-occurrence of pain and depression was not supported, but specific findings did suggest that the right hemisphere may play a unique role in pain perception. Data from the visual task indicated that prior exposure to pain results in increased right hemisphere activation as indicated by a left visual field bias. Pain perception was a complex function of mood, preceding tasks, and the hand tested, and it was suggested that exposure to a typical right-hemisphere task increased the left side lateralization of pain in nondepressed subjects. Implications of these findings are discussed for coexisting problems of pain and depression and for the lateralization of pain in disorders judged to involve a significant psychogenic component.
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PMID:Depression, pain, and hemispheric activation. 270 26

The influence of cold on the threshold for myocardial ischemia and the efficacy of antianginal drugs in a cold environment were assessed in 24 patients with stable angina and exercise-induced ST depression. Treadmill exercise tests were done according to a randomized double-blind protocol 90 minutes after administration of placebo, 80 mg propranolol, or 120 mg diltiazem, each at both -8 degrees and 20 degrees C. Eight of the patients were classified by history as cold-sensitive before the study. For the entire group, none of the exercise end points differed significantly between cold and normal temperatures with placebo. However, cold-sensitive patients developed 1 mm ST depression 30% sooner (169 +/- 41 versus 244 +/- 38 seconds, p less than 0.01) at -8 degrees C compared with 20 degrees C. At the onset of ischemia, rate-pressure product was lower in the cold (19.8 +/- 1.0 versus 22.0 +/- 1.6 x 10(-3), p less than 0.05). Both propranolol and diltiazem prolonged time to onset of 1 mm ST depression at both temperatures. The magnitude of improvement at -8 degrees C was equal to that at 20 degrees C, and differences between the two drugs were not statistically significant. Only diltiazem prolonged total exercise duration. Thus, as assessed by exercise testing, cold does not worsen ischemic threshold in most stable angina patients. However, in a subgroup identifiable by history, ischemic threshold is lower in the cold. Propranolol and diltiazem are as effective for exercise-induced ischemia in a cold environment as at normal temperatures.
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PMID:Exercise-induced myocardial ischemia in a cold environment. Effect of antianginal medications. 271 70


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