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At least 1,729 records · Page 96Linked to original sources
PubMed1996

[Montirelin hydrate (NS-3), a TRH analog, improved disturbance of consciousness in cats: electroencephalographical studies].

Central effects of montirelin hydrate (NS-3) were electroencephalographically investigated in cats with experimentally induced disturbance of consciousness. All experiments were conducted under the gallamine-immobilized and artificially ventilated acute experimental condition. NS-3 and TRH produced EEG activation in cats with lesions in the midbrain reticular formation in a dose-dependent manner. Similar effects were observed in cats with bilateral lesions of the posterior hypothalamic area. These effects of NS-3 were 30 to 100 times more potent than those of TRH. NS-3 at doses higher than 0.003 mg/kg restored the suppressed EEG dose-dependently in cats with cerebral ischemia produced by clamping the bilateral common carotid arteries and basilar artery. TRH showed no effect at a dose of 10 mg/kg. These results indicate that NS-3 might be an effective drug for treating the disturbance of consciousness.

Animals↗
PubMed1998

Variation of monoamines and their metabolite contents in the cerebrospinal fluid of conscious rats.

To study the circadian rhythm of the monoamine and metabolite contents, cerebrospinal fluid was taken from the cisterna magna through a polyethylene catheter tube every 4 hr in the conscious rat. Norepinephrine and 3-methoxy-4-hydroxy-phenylglycol were found to describe a rhythm with the maximal content occurring during the dark phase and the minimal content occurring during the light phase. Dopamine levels increased significantly during the light phase compared with the dark phase. These results, given that cerebrospinal fluid can be taken chronically from conscious rats, indicate that our present method may be suitable for estimating changes in brain monoamine and metabolite contents.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1989

[Studies on the computer simulated model of toluene elimination from the brain using HPLC measured urinary hippuric acid and the patient's consciousness level and its medical implications].

Urine specimens were sampled from toluene exposed persons (2 painters, 2 plasterers and 1 addict of organic solvent), who were admitted to the critical care center of our medical school and the urinary hippuric acid (HA; the metabolite of toluene) was monitored every one hour after admission for 10-12 hours and thence-forth every 4 hours for more than 40 hours. The hourly (t) excretion pattern of HA(Y) was simulated with multiexponential functions; Y = sigma Ai.exp(-Bit).....(1), i = 1 to 3. The HA(Y) level during the term before the admission was estimated by equation (eq.) (1) for the respective cases. The consciousness level was evaluated according to the Japan Coma Scale on the following time points; on the telephone call to the emergency center (t1), on the arrival of the ambulance (t2) and on admission (t3). We related the differential change of the consciousness level (w) per time (between t1 and t2); delta w/delta t to one of the regression coefficients (Bi) of eq. (1) expressing the elimination of toluene from the body. A set of Bi whose scale parameter Ai is positive and whose absolute value is the minimum in the individual eq. (1) has the highest correlation coefficient with the value of delta w/delta t (r = -.870, p less than .05). We calculated the toluene elimination equivalent (X) from the brain by applying this Bi to the equation; X = exp(-Bit) on the respective time point, t1, t2 and t3, and related this X to W by simulating a logistic eq.; W = 3.0/[1 + exp[alpha(X - beta]].....(2), as to each respective case. The calculated values by eq. (2) for the occupationally toluene exposed cases revealed that the scale parameter (alpha) and the location parameter (beta) correlated well with the integral HA excretion value for 48 hours computed by eq. (1), and the elimination rate equivalent (Bi), respectively. But the calculated data of the solvent addict using eq. (2) indicated that there is a tolerance mechanism against toluene exposure; the scale parameter is larger and the location parameter is smaller than the respective ones from the painters and the plasterers.

Accidents, Occupational↗
PubMed1990

Respiratory activity of the cricothyroid muscle in conscious humans.

The cricothyroid muscle serves as an accessory muscle of respiration in anesthetized animals. The functional significance of this activity is unknown. To determine respiratory cricothyroid muscle activity in conscious humans, cricothyroid muscle electromyogram was measured percutaneously, along with posterior cricoarytenoid muscle electromyogram and esophageal pressure in six volunteers. Low level cricothyroid muscle activity with quiet breathing was observed in four subjects. In all subjects, cricothyroid muscle activity was recruited by voluntary deep breathing, brief airway occlusion, and hypercapnia. Continuous positive airway pressure at 7.5-cm H2O increased expiratory cricothyroid muscle activity in all subjects, and suppressed inspiratory activity in five. These results indicate that respiratory reflexes of the cricothyroid muscle are operative in conscious humans.

Adult↗
PubMed1998

Interaction of opioids and vasopressin in central action of angiotensin II in conscious rabbits.

It has been demonstrated that opioids modulate the renin-angiotensin and sympathetic nervous system. To clarify the interaction of central angiotensin II (Ang II) and endogenous opioids, we studied the effects of naloxone, an opioid antagonist, on cardiovascular and sympathetic responses to intracerebroventricular (i.c.v.) Ang II in conscious rabbits. I.c.v. Ang II (20 ng/min) significantly increased mean arterial pressure (MAP), plasma epinephrine, and arginine vasopressin (AVP) levels, with no significant change in renal sympathetic nerve activity (RSNA) or heart rate. Pretreatment with intravenous naloxone (0.1 mg/kg) failed to alter the cardiovascular and neurohormonal responses to i.c.v. Ang II. To eliminate the effect of AVP on cardiovascular and sympathetic responses, [d(CH2)5Thy(Me)]AVP, a vasopressin V1-receptor antagonist, was given intravenously. Pretreatment with intravenous injection of the V1-receptor antagonist (30 micrograms/kg) augmented the maximum increase in RSNA caused by i.c.v. Ang II (8.9 +/- 2.2 vs. 16.2 +/- 0.7%, p < 0.05). Combined pretreatment with naloxone and V1-receptor antagonist further increased MAP and RSNA in response to ICV Ang II (20 +/- 1 vs. 16 +/- 2 mmHg, p < 0.05, and 30.9 +/- 3.7 vs. 16.2 +/- 0.7%, p < 0.01, respectively). These results suggest that opioids and AVP synergistically modulate sympathetic outflow so as to suppress the central pressor action of Ang II in conscious rabbits.

Angiotensin II↗
PubMed2006

Effect of traditional acupuncture on proximal colonic motility in conscious dogs.

Acupoints on the Large Intestine Meridian and specific acupoints related with large intestine have been empirically used to treat large intestinal disease. However, the relationship between acupoints related with large intestine and their functions has not been investigated fully. We investigated whether large intestine-related acupoints affect colonic motility in conscious dogs implanted with electrodes at the proximal colon. Manual acupuncture was applied at the following acupoints: 7 main points on the Large Intestine Meridian (LI1, LI2, LI3, LI4, LI5, LI6, and LI11), ST25, BL25 or GV1. Acupuncture at the Large Intestine Meridian acupoints, ST25 and BL25 had no significant effects on the proximal colonic motility. However, acupuncture at GV1 depressed the proximal colonic motility by decreasing the total duration and the frequency of contractile states, which may contribute to the therapeutic effects of GV1. This study also revealed that there was no clear correlation between Large Intestine Meridian and the proximal colonic motility in conscious dogs.

Acupuncture↗
PubMed1984

Ventilatory effects of doxapram in conscious human subjects.

The ventilatory effects of a bolus intravenous dose of doxapram (0.37 to 0.47 mg/kg) were studied in ten healthy normal subjects. An immediate significant (p less than 0.001) increase in minute ventilation (VE) was due, in equal part, to significant increases in tidal volume (VT) and frequency (f). The inspiratory (TI) and expiratory time (TE) per breath decreased significantly. Mouth occlusion pressure increased significantly, in association with the increase in VT; there was no change in the ratio of VE to mouth occlusion pressure, indicating that respiratory mechanics did not alter. These results indicate that doxapram increases ventilation in conscious, normal man by an increase in inspiratory neuromuscular drive and a change in central breath timing. The ventilatory and mouth occlusion pressure responses to progressive isocapnic hypoxia and progressive hyperoxic hypercapnia were significantly altered by an intravenous infusion of doxapram (1 mg/min) only in the elevations (Y-intercepts) of the slopes of VE and mouth occlusion pressure; the regression coefficients did not change significantly. These results indicate that in conscious normal subjects, doxapram acts on both the peripheral and central respiratory receptors.

Adult↗
PubMed2003

Pursuing relational consciousness: thinking and antithinking in group.

Although human beings are interpersonal and innately curious, at the same time an aspect of the self defends against mental relationships with self and other, because such relationships threaten to cause psychic pain. Bion's ideas on thinking and antithinking are applied to this topic of relational consciousness: A "psychotic part of the personality"--which refers also to the "basic assumptions" level of the group-prefers antithinking: forestalling, evading, and assaulting thinking and thinkers. Clinical examples illustrate how the group therapist may address and treat the pervasive resistances to relational consciousness in the group setting. These involve understanding the dynamics and clinical manifestations of hatred of thinking, excessive projective identification, anticipatory anxiety regarding thinking, and bizarre and hallucinatory thought transformations.

Consciousness↗
PubMed2006

Localization of tactile stimuli depends on conscious detection.

Neurological reports of "tactile blindsight" suggest that the human somatosensory system can extract behaviorally useful information about the location of a tactile stimulus in the absence of conscious awareness that the stimulus occurred (Paillard et al., 1983; Rossetti et al., 1995). However, in a series of psychophysical experiments with neurologically intact subjects, we found no evidence for such a dissociation. Our subjects' ability to name the finger on which a tactile stimulus had been presented was dependent on their ability to consciously detect that stimulus (Harris et al., 2004). The present experiments followed up on this study and specifically sought evidence for a dissociation when subjects were required to indicate the location of the stimulus either by pointing at or moving the stimulated finger, the same response made by the neurological patients. Once again, localization accuracy was correlated with detection, and, crucially, when both detection and localization were measured using equivalent forced-choice tasks, the subjects were completely unable to identify the location of stimuli that they had not detected. These findings are inconsistent with the dissociation implied by the cases of tactile blindsight, but are consistent with other neurological evidence that detection of a tactile stimulus does not depend on localization (Head and Holmes, 1911; Halligan et al., 1995; Rapp et al., 2002).

Adolescent↗
PubMed1975

Hemodynamics of spontaneously hypertensive rats in conscious state.

Cardiac output of unanesthetized spontaneously hypertensive rats (SHR) and normotensive control rats (NCR) was measured by an aortic pressure pulse contour method. A catheter was introduced into the aortic arch under ether anesthesia and aortic pressure curves were recorded after the recovery from anesthesia. Stroke volume was calculated by reading required pressure and time data on the tracings and substituting them into a special equation. Cardiac output per min per body weight was not significantly different between SHR and NCR. Arterial pressure and total peripheral resistance were higher in SHR than in NCR. On ganglion blockade with hexamethonium bromide in the conscious state, arterial pressure decreased more markedly in SHR than in NCR. Though arterial pressure was still significantly (P less than 0.05) higher in SHR after blockade, cardiac output was larger in SHR more than to account for the difference in arterial pressure. Total peripheral resistance was lower in SHR than in NCR after blockade. It is concluded that, even in the conscious state as in the anesthetized state, the major contribution to the hypertensive state in SHR is an increase in total peripheral resistance due to an elevation of the sympathetic tone.

Anesthesia↗
PubMed1983

Effects of intracerebroventricular administration of prostaglandin D2 and angiotensin II on blood pressure in conscious rats.

To evaluate the role of brain prostaglandins in the regulation of blood pressure, we examined the effects of intracerebroventricular injections of prostaglandin D2, angiotensin II and indomethacin on blood pressure in conscious rats. Intraventricular administration of prostaglandin D2, the major prostaglandin synthesized in the rat brain, did not elicit a significant change in blood pressure. On the other hand, intraventricular injection of angiotensin II resulted in an increase in blood pressure in a dose-related manner. However, this central pressor effect of angiotensin II was not affected by intraventricular pretreatment with indomethacin. Indomethacin per se did not induce any change in blood pressure. These results suggest that prostaglandin D2 in the brain does not play an important role in the regulation of blood pressure in conscious rats. It is also suggested that the central pressor effect of angiotensin II is not mediated by prostaglandin biosynthesis in the central nervous system.

Angiotensin II↗
PubMed2004

Role of nitrergic input in mechanically and chemically induced gastric relaxation in conscious dogs.

Our aim was to study a role of nitrergic input in gastric relaxation in conscious dogs. Proximal gastric motor responses to mechanical distension and chemical stimulation (a lipid meal orally) were evaluated by electronic barostat. Effect of N(G)-monomethyl-L-arginine acetate (L-NMMA, 5 mg/kg) on these responses was studied. When mechanical stimulation was applied, we observed steep linear increases in intragastric pressure up to about 6 mmHg, then continued to increase gradually, and could be increased still further upon the addition of L-NMMA. Oral application of a lipid led to a prompt fall in intragastric pressure (gastric receptive relaxation; GRR). Lipid treatment also led to a considerable increase in gastric volume (means +/- S.D., 150.0 +/- 50.2 ml), this was followed by a plateau phase and a gradual return to baseline levels. Neither GRR nor the associated increase in gastric volume (167.6 +/- 53.0 ml) was sensitive to treatment with L-NMMA. Our conclusion is that nitrergic input is necessary for mechanically induced gastric relaxation, but not for either GRR or chemically-induced gastric relaxation in conscious dogs.

Animals↗
PubMed1998

Cerebrospinal fluid syndromes in patients with acute consciousness compromise.

We reviewed the laboratorycards of 200 analysis of cerebrospinal fluid (CSF) performed to evaluate acute alterations of consciousness in adult patients attended in a neurological emergency room. 61% were men; the mean age was 46 years. The most common clinical data were infective and neurologic. The CSF was abnormal in 149 (74.5%) patients and the most common syndromes were: compressive (21%), hemorrhagic (11.5%), "viral" (8.5%), septic (7.5%), moderate hyperglycorrachia (6.5%), hydroelectrolytic disturbances (5.5%). There were some statistically significant correlations between CSF syndromes and clinical data: septic syndrome and fever and meningeal signs, hemorrhagic syndrome and headache and meningeal signs, CSF hydroelectrolytic disturbance syndrome and seizures, severe hyperproteinorrachia and headache, fever, meningeal signs and vomiting, moderate hyperproteinorrachia and age over 65 and male sex. We classified the abnormal results in two groups: 1--sufficient for an immediate clinical decision; 2--nonspecific. The former group was found in 27.5% of the patients and in 36.9% of the abnormal CSF results. In patients attending to neurologic emergency rooms with acute alterations of consciousness, the examination of the CSF frequently could contribute to an etiologic diagnosis. It must be performed after a rigorous clinical evaluation of the patient.

Acute Disease↗
PubMed2004

A hybrid neural network model for consciousness.

A new framework for consciousness is introduced based upon traditional artificial neural network models. This framework reflects explicit connections between two parts of the brain: one global working memory and distributed modular cerebral networks relating to specific brain functions. Accordingly this framework is composed of three layers, physical mnemonic layer and abstract thinking layer, which cooperate together through a recognition layer to accomplish information storage and cognition using algorithms of how these interactions contribute to consciousness: (1) the reception process whereby cerebral subsystems group distributed signals into coherent object patterns; (2) the partial recognition process whereby patterns from particular subsystems are compared or stored as knowledge; and (3) the resonant learning process whereby global workspace stably adjusts its structure to adapt to patterns' changes. Using this framework, various sorts of human actions can be explained, leading to a general approach for analyzing brain functions.

Algorithms↗
PubMed1985

Growth hormone responses to multiple injections of a fragment of human growth hormone-releasing factor in conscious male and female rats.

The GH responses to single i.v. injections of GH-releasing factor (GRF) in conscious male rats are highly variable. Although normal male rats show a pulsatile secretory pattern of GH with pulses occurring at intervals of 3-3.5 h, the peaks occur at different times in individual animals. We have compared the GH responses of young conscious male and female rats to multiple i.v. injections of 1 microgram human (h) GRF1-29NH2. The peak GH responses occurred 3-5 min after hGRF1-29NH2 injection and were lower in female than in male rats. Both males and females responded uniformly to hGRF1-29NH2 injections given 180 min apart and the GH responses became entrained with no endogenous GH pulsing. Female rats produced consistent GH peaks in response to hGRF1-29NH2 injections at 90-min intervals, whereas male rats responded only to alternate injections, so that GH peaks occurred only every 180 min despite giving GRF every 90 min. When the frequency of hGRF1-29NH2 administration was increased to once every 40 min female rats again responded consistently to each injection. Male rats responded intermittently, being able to respond to two injections 40 min apart, after which they became refractory to hGRF1-29NH2. This cycle of varying sensitivity to GRF in male rats probably underlies their 3-hourly endogenous GH secretory rhythm. Female rats can respond uniformly to repeated GRF injections, consistent with their more continuous pattern of endogenous GH secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Pharmacodynamics of carvedilol in conscious, healthy dogs.

The purpose of the study reported here was to determine the magnitude and duration of beta-blocking efficacy, determine an effective dose and dosing interval, and document safety and tolerability of carvedilol given orally in clinically normal dogs. Pharmacodynamic data were evaluated in conscious, unrestrained, healthy hound dogs at baseline and after long-term oral administration of carvedilol (1.5 mg/kg of body weight PO q12h for >5 days). At baseline, heart rate (HR) and blood pressure (BP) data were collected continuously for 24 hours, and complete echocardiography was performed. This protocol was repeated after long-term oral carvedilol administration. Additionally, isoproterenol was administered to evaluate the magnitude and duration of the nonselective beta-blocking efficacy of carvedilol. An isoproterenol challenge was performed 0.75, 1.5, 2.25, 4, 6, 12, and 24 hours after carvedilol administration, with echocardiography being performed once at 2 hours. Plasma samples were obtained prior to each challenge time point for determination of plasma carvedilol concentration. Time series regression analysis indicated no difference between baseline and carvedilol-induced HR or BP trend lines in 6 of 8 dogs. In 2 of 8 dogs, HR, after long-term carvedilol administration, was reduced. Carvedilol attenuated isoproterenol-induced changes in HR by 54-76% through 12 hours and by 30% at 24 hours. The BP changes were attenuated by 80-100% through 12 hours. These data suggest that carvedilol (1.5 mg/kg PO q12h) in healthy, conscious dogs confers nonselective beta blockade for 12 hours, with minimal effects on resting HR, BP, and echocardiographic variables. Additionally, the magnitude of beta blockade correlated strongly to peak plasma carvedilol concentration, suggesting that therapeutic drug monitoring may be clinically useful.

Adrenergic beta-Antagonists↗
PubMed1994

Diaphragmatic electrical activity during controlled and assisted mechanical ventilation in conscious human subjects.

Breathing during mechanical ventilation was analyzed in 8 conscious healthy volunteers by application of intermittent positive pressure ventilation through a mouthpiece. In controlled mechanical ventilation (CMV), the respiratory rate and tidal volume were fixed at 110 and 120% of the subject's corresponding spontaneous breathing parameters. The diaphragmatic electromyogram (EMGdi) decreased significantly but become synchronous with the rhythm of the CMV. In assisted mechanical ventilation (AMV), the EMGdi response developed prior to and during the inspiratory phase of AMV. Application of an unexpected mechanical breath elicited the EMGdi. As the triggering sensitivity was decreased, the EMGdi prior to and during a mechanical breath was augmented, however, its rate of rise was unaffected. Our results suggest that the EMGdi during mechanical ventilation in conscious subjects is initiated by the respiratory center, however, this activity is modulated strongly by input from the pulmonary afferents and from the cerebral cortex.

Cerebral Cortex↗
PubMed1990

Necessity of hyperglycemia for effects of endogenous cholecystokinin on insulin and pancreatic exocrine secretion in conscious rats.

The effects of endogenous cholecystokinin (CCK) on insulin and pancreatic exocrine secretion were examined in conscious rats. Rats with bile and pancreatic fistulae, one duodenal cannula, and two jugular vein cannulae were divided into four groups, with and without glucose infusion (0.2 g/(ml.h)), and with bile and pancreatic juice (BPJ) diversion and return. Without glucose infusion, BPJ diversion did not have any significant effect on the plasma level of insulin or glucose; but with glucose infusion, it caused a significant increase in plasma insulin concentration 1 h after the diversion. The plasma glucose concentrations in the groups with BPJ diversion and return were not significantly different, and the response of pancreatic exocrine secretion to BPJ diversion was suppressed slightly, but not significantly, by glucose infusion. The plasma CCK concentration was increased significantly by BPJ diversion, but not affected by glucose infusion. These results indicate that, as observed in in vitro experiments with exogenous CCK, in conscious rats, endogenous CCK stimulates both exocrine and endocrine secretion of the pancreas, and that hyperglycemia is necessary for these effects to become apparent.

Animals↗