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)

1. Experiments based on teased fiber recording from rat sciatic nerve have shown that a small proportion of primary afferent neurons in intact dorsal root ganglia (DRGs) fire spontaneously. The prevalence of this discharge is substantially increased if the sciatic nerve has been chronically injured. 2. We now show that in most cases this ongoing DRG activity can be augmented by tetanic stimulation of the axons of neighboring neurons, where the active neuron itself has not been stimulated. In addition, some previously silent DRG neurons can be cross-excited by neighbors. This novel form of neuron-to-neuron communication is termed "DRG crossed afterdischarge." Cross-excitation never occurred at fixed latency in response to single stimulus pulses and is therefore not a case of ephaptic cross talk. 3. Crossed afterdischarge occurred only if the spontaneously active neuron and the stimulated neighbors shared the same DRG. It occurred in 83.5% of the spontaneously active neurons sampled that had myelinated (A) axons, but in only 4.4% of spontaneously active neurons with unmyelinated (C) axons. Among initially silent neurons, stimulation of neighbors evoked firing in 3.1% of A-fibers but in no C-fibers. 4. Crossed afterdischarge responses began within 500 ms of stimulation onset (with the use of 50-Hz tetani) and increased in magnitude for about the first 30 s of stimulation, declining thereafter. Intense excitations were often followed by a short period of depression until the original rate of ongoing discharge was restored. 5. The magnitude of crossed afterdischarge responses increased with increasing stimulation frequency until saturation. Minimal responses occurred with the use of tetani of as little as 1 Hz. Maximal responses occurred with the use of 100-200 Hz tetani. 6. The inclusion of C-fibers in the afferent volley produced little if any augmentation of responses. 7. Cross-excitation was demonstrated in DRGs in which many or all peripheral afferent axons were intact and continued to innervate hind limb skin. In these preparations natural cutaneous stimulation was shown to be capable of evoking crossed afterdischarge responses. The most effective stimuli were gentle or firm rubbing of the foot. Noxious pinch, heat, cold, and chemical stimulation was ineffective. 8. DRG crossed afterdischarge is a mechanism whereby sensation in response to peripheral stimulation may be distorted in time, space, and modality. Because its prevalence is much increased after axotomy, it might contribute to neuropathic sensory abnormalities, including pain, in patients with nerve injury.
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PMID:Cross-excitation in dorsal root ganglia of nerve-injured and intact rats. 207 61

In order to evaluate perioperative electrical cardiac disturbances and ST segment changes, 42 patients (38 M, 4 F, aged 57 +/- 6 ys) were studied using 24-hour Holter monitoring before, during and after coronary bypass surgery. In the 4-6 hours before cardioplegic arrest, 38% of patients had ST segment changes. No patient and malignant arrhythmias. The injection of cold cardioplegic solution was followed by bradycardia, ventricular tachycardia, ventricular fibrillation and isoelectric line within 2-4 minutes. After aortic declamping, 30 patients were defibrillated. Impulse formation and conduction disturbances, found in 55% of patients, solved themselves in 1 to 60 minutes. Bundle branch block continued in just 4 cases. A total of 59% of patients had ST segment elevation for 14 +/- 14 minutes and 19% had ST segment depression for 19 +/- 20 minutes. Successive transient ST segment changes were detected in 38% of patients. Sustained ventricular tachycardia occurred during 2 ischemic episodes. Impulse formation and conduction disturbances were not related to the duration of cardiac arrest or ventricular fibrillation, but were more frequent and lasted longer in patients with incomplete revascularization. Transient ST segment depression far from aortic declamping correlated with preclamping ischemia. Transient ST segment elevation correlated with incomplete revascularization. We concluded that ECG signs of intraoperative damage were reversible. Moreover, perioperative transitory ischemia was frequent but could be prevented by coronary active drug administration. On the other hand incomplete revascularization was associated with electrical disturbances and ischemia.
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PMID:[Intra- and perioperative arrhythmia and ischemic signals in myocardial revascularization patients]. 209 May 45

In this study the prognostic significance of a set of quality of life measures was tested with regard to mortality regardless of its cause, cardiovascular mortality, cancer mortality and mortality from other causes. From the population register of Gothenburg, Sweden, a sample was drawn consisting of one third of all 60-year-old men. The 945 men who met the criteria were invited to a medical examination. Information on the occurrence of 30 symptoms and 15 measures of well-being was obtained by questionnaire. Mortality data were obtained through official registers, death certificates and medical records. Of the symptoms at 60, breathlessness, cough, depression, bad appetite and feeling cold, all were significantly related to mortality during 15 years of follow-up. Of the well-being variables, the same was true of perceived health, physical fitness and appetite. This means that the quality of life has a strong bearing not only on the present life situation for these men but also for their future health.
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PMID:Is quality of life affecting survival? The study of men born in 1913. 210 Mar 66

De novo phospholipid biosynthesis was assayed in isolated hepatocytes of rainbow trout (Oncorhynchus mykiss) both fully acclimated to 5 or 20 degrees C and undergoing acclimation from one temperature extreme to the other. Incorporation of [14C]choline, [3H]ethanolamine, and [3H]serine into phosphatidyl-choline (PC), phosphatidylethanolamine (PE), or both, was followed to assess metabolic capacity. PE biosynthesis rates exceeded those for PC four- to fivefold. Methylation of PE accounted for 10 (20 degrees C)-17% (5 degrees C) of the synthetic capacity for PC, whereas 6 (20 degrees C-acclimated)-27% (5 degrees C-acclimated) of PE synthesis was derived from phosphatidylserine (PS) decarboxylation. Several factors may contribute to the altered proportions of PE and PC or unsaturated molecular species of phospholipids characteristic of thermally acclimated animals. 1) Activities of choline and ethanolamine phosphotransferase pathways were significantly higher, and decarboxylation activity lower, in 20 degrees C than in 5 degrees C-acclimated trout, resulting in maintained PE synthesis despite a general depression of lipid biosynthesis at cold temperatures. 2) PC biosynthesis depended more on temperature (Q10 = 2.6-3.0) than that of PE (Q10 = 1.8-2.2), causing the ratio of PC/PE synthesis to be positively correlated with temperature. 3) Contribution of methyltransferase pathway to the synthesis of PC was higher at 5 than 20 degrees C. 4) The percentage of ethanolamine incorporation recovered in PC increased threefold in the early stages of warm acclimation. However, not all adjustments in biosynthetic capacity (most notably a 10-fold stimulation of PC synthesis 2 days after transfer of warm-acclimated trout to 5 degrees C) influence membrane lipid composition, implicating other processes in the regulation of this parameter.
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PMID:Adaptation to temperature: phospholipid synthesis in hepatocytes of rainbow trout. 216 24

Verapamil elimination kinetics and pharmacodynamic effects were studied in 29 healthy individuals (23-81 years of age) after single i.v. doses (0.15-0.22 mg/kg) and during infusions to reach stable plasma verapamil concentrations of 28 +/- 11, 57 +/- 19 and 112 +/- 26 ng/ml (mean +/- S.D.). Aging prolonged verapamil elimination (P less than .008): elimination half-life of 218 +/- 91 min in young (ages 20-39), 280 +/- 78 min in middle-aged (40-59) and 288 +/- 73 min in elderly (greater than 60). After single verapamil doses. 1) heart rate increased with lesser increases in elderly subjects; 2) blood pressure decreased (P = .006) with greater decreases in elderly subjects; 3) spontaneous P-R intervals increased with lesser increases in elderly subjects but, 4) atrioventricular conduction times increased during transesophageal pacing without detectable age differences in responses. During steady-state infusions, 1) heart rate during sinus rhythm was unchanged but atrioventricular dissociation with junctional rhythms developed in elderly subjects (3/9); 2) blood pressure decreased with greater decreases in the elderly; 3) spontaneous P-R intervals increased with lesser increases in the elderly but no age differences in paced P-R interval changes were detected at equivalent verapamil concentrations; 4) heart rate variation (during sinus rhythm) decreased in an age-independent manner as measured by decreases in the S.D. of R-R intervals and decreased power spectral content with greatest changes seen in high frequency (respiratory) content; and 5) heart rate and blood pressure responses to cold pressor and handgrip testing were not attenuated by verapamil. In conclusion, aging prolongs verapamil elimination and alters dynamic responses to verapamil with greater sinus node depression and hypotensive effects in elderly vs. younger subjects. Although less spontaneous P-R interval prolongation was seen on ECG of the elderly vs. young, underlying atrioventricular conduction was prolonged by verapamil independent of age as shown by results when pacing was used to eliminate frequency-dependent effects caused by differing heart rate responses.
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PMID:Aging alters verapamil elimination and dynamics: single dose and steady-state responses. 221 68

Cold exposure accelerates the firing frequency of norepinephrine (NE) neurons, enhancing NE release and leading to NE depletion in specific regions of the brain. The accelerated firing activates the enzyme tyrosine-hydroxylase, making it more tyrosine sensitive. The reduction of brain NE is accompanied by a behavioral depression on the open field test. Two experiments were performed on adult male rats. First, it was determined whether systematic lowering of core body temperature produced behavioral depression in the swim test. Second, treatment with the NE precursor tyrosine was employed in an attempt to prevent hypothermia-induced behavioral depression. In Experiment 1, two levels of hypothermia were highly effective in producing behavioral depression in rats forced to swim in a narrow cylinder. In Experiment 2, treatment with tyrosine (400 mg/kg, IP) thirty minutes prior to the hypothermia procedure completely reversed the behavioral depression found in Experiment 1. Tyrosine administration did not significantly influence the rate of deep body cooling during the hypothermia treatment.
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PMID:Tyrosine pretreatment reverses hypothermia-induced behavioral depression. 231 Sep 42

The effects of cold-restraint as a physiological stressor on the glutathione (GSH) content of the liver and other tissues were examined in male mice. Mice of the ICR, NIH, ND/4, and B6C3F1 strains subjected to cold-restraint for 2 or 3 h experienced a loss of hepatic GSH concentrations ranging from approximately 15 to 50%. Though 3 of these strains (ICR, NIH, and B6C3F1) experienced hypothermia as result of the cold-restraint treatment, with average decreases in core body temperature ranging from 3.3 to 9.8 degrees C, hepatic GSH levels were depressed in the ND/4 mouse in the absence of changes in core body temperature. The ability of cold-restraint as a stressor to diminish hepatic GSH therefore could not be attributed simply to hypothermia. The decrease in hepatic GSH from cold-restraint in ND/4 mice was paralleled by a decrease in non-protein sulfhydryl (NPSH) content of the liver. In addition to its effects on liver GSH and NPSH concentrations, 1.5 h of cold-restraint stress significantly depressed plasma, heart, kidney, and lung NPSH concentrations. The extent of NPSH depression was equivalent to the GSH depression in the liver, heart, and kidney, despite the observation that the normal contribution of GSH to total NPSH content in these tissues ranged from a high of 89% (liver) to a low of 49% (heart). These results with cold-restraint in the ND/4 mouse suggest that other stressors may significantly depress cellular concentrations of GSH and other thiols, and may thereby render the affected tissues more susceptible to the toxicity of free radicals, electrophilic xenobiotic metabolites, or reactive oxygen species.
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PMID:Depression of glutathione by cold-restraint in mice. 231 51

Skiing, which may involve strenuous exercise in the cold at high altitude, could place considerable stress on the coronary circulation. To explore this possibility, we obtained by telemetry electrocardiograms on 149 men during recreational skiing at altitudes above 3100 m (10 150 ft). Tachycardia was impressive; heart rate exceeded 80% of predicted maximum in two thirds of the subjects. Five men developed abnormal ST-segment depression during or immediately after exercise. All five were older than 40 years, so in this age group the incidence of ST abnormalities was 5.6%. This is not greater than the incidence among asymptomatic men during submaximal exercise at low altitude. The high level of physical fitness of men who ski may have offset the added stress of cold and hypoxia. Hence, for physically fit older men, mountain skiing does not appear to pose a greater coronary stress than does comparable exercise at low altitude among men of only average physical fitness without known heart disease.
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PMID:The coronary stress of skiing at high altitude. 235 53

The voices of patients suffering from Parkinson's disease change in various ways. This paper sets out to examine the effect of these changes on the impressions made on listeners, and to try to see what vocalic and prosodic features account for these impressions. Tape recordings from segments of interviews with 4 patients, and 4 control subjects with ischaemic heart disease, were played to 16 naive listeners. These listeners were asked to rate their impressions of these voices on 15 dimensions of personality. There were significant differences on most of the dimensions, despite the fact that there were no differences between the two groups on such scales as Beck's depression inventory and the mood adjective check list. The parkinsonian patients were seen to be cold, withdrawn and anxious, not to relate well to the interviewer and to be enjoying the interview less than the controls. These ratings are very similar to those previously reported for the same patients, using silent video recordings only. The voice recordings were analysed along various dimensions of prosody. The factors which were different between the groups included the frequency and type of pauses in speech and the range or variability of the fundamental frequency. The implications of this exploratory study for intervention are discussed.
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PMID:Impressions of parkinsonian patients from their recorded voices. 237 6

The effect of pentobarbital and isoflurane on cerebral glucose metabolism (CMRglc) was studied in thermally injured rat brain using quantitative autoradiography. In awake lesioned animals, CMRglc in cortical regions ipsilateral to the injury was reduced to 50% of normal while little if any decrease was observed in contralateral cortical regions and subcortical regions bilaterally. Treatment of lesioned animals with pentobarbital or isoflurane further reduced CMRglc, but more in the hemisphere contralateral to the injury than on the injured side. Thus, the side-to-side difference in cortical CMRglc present in the awake lesioned animals was abolished by the anesthetics. The results support the hypothesis that CMRglc depression associated with a focal cold injury is functional in nature. Reduction of metabolism by anesthetics in functionally depressed brain is limited by the decrease in CMRglc associated with the injury.
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PMID:The effect of pentobarbital and isoflurane on glucose metabolism in thermally injured rat brain. 238 35


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