A brain death model with slow induction for experimental studies of organ donation
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Aim. To test in experiment a pathogenetically adequate model of brain death due to increased intracranial pressure with gradual induction, allowing the evaluation of the changes occurring in the organs of a potential donor. Materials and methods. 6–8 months old outbred male rats of the experimental group ( n = 18) and the control group ( n = 8) were anesthetized, the left common carotid artery was catheterized to record systolic, diastolic blood pressure (BP) and heart rate (HR), the mean BP (MBP) was calculated. After transfer to artifi cial ventilation, brain death was simulated in the experimental group using the developed method. Results. All animals in the experimental group suffered brain death 30 minutes from the start of the experiment;10 rats (56%) died within 3 hours due to progression of circulatory failure. Initially, in anesthetized animals, MBP was 101 (90; 105) mm Hg, HR 310 (297; 315) beats/min. After 5 minutes from the start of brain death induction, MBP increased to 147 (140; 150) mm Hg ( p = 0.01), HR to 396 (384; 406) beats/min ( p = 0.03). Further, within 20 minutes there was a decrease in MBP to 94 (90; 100) mm Hg and HR to 290 beats/min. During the observation period from 26 to 90 minutes, there was a stabilization of MBP at the level of 87–92 mm Hg, there was a tendency to bradycardia with HR from 263 to 274 beats/min ( p = 0.01). Then after 120–150 minutes from the beginning of brain death induction, MBP continued to decrease to 75–80 mmHg ( p = 0,03), HR to 256–264 beats/min ( p = 0,01). At the end of the experiment, despite volemic support, MBP decreased to 64 (61; 67) mm Hg ( p = 0.02), bradycardia worsened with HR to 250 (248; 260) beats/min ( p = 0.01), indicating the hemodynamic decompensation. Conclusion. The results of experimental testing of an animal brain death model on outbred rats showed that this model is pathogenetically adequate and useful to assess the condition of potential donor organs within 3 hours after the induction of brain death.Behavior and heart rate response of seven ornate box turtles (Terepene ornata) to visual threat, touch, forced diving, and voluntary diving were investigated. Visual stimulus resulted in two different behavioral and two different heart rate responses. Three of seven turtles turned and walked away from the stimulus with no change in heart rate. Four turtles stopped walking and withdrew their feet and head. Heart rate was reduced 37%. Atropine had no effect on behavior but abolished bradycardia. Tactile stimulus resulted in withdrawal of feet and head and reduction of heart rate by each of the turtles. Heart rate was reduced 68%. Atropine abolished bradycardia but did not alter behavior. Reduction in heart rate was instantaneous and occurred during the first R-R interval following stimulus. Forced diving reduced the heart rate 56%. Bradycardia was abolished with atropine. Bradycardia onset was gradual, suggesting chemoreceptor involvement. Voluntary diving was not accompanied by bradycardia.
Stimulus (psychology)
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Ultrasonographic research on intima-media thickness of common carotid artery and vascular compliance
Objective: To investigate the relationship between intima-media thickness of the common carotid artery and vascular compliance. Methods: 120 subjects were divided into three groups, 40 normotensive individuals as the control group, 47 subjects in non-carotid artery plaque group, and 33 patients in carotid artery plaque group, IMT and diameter of CCA were measured using HP-5500 ultrasound with a high-resolution probe, blood pressure and artery compliance (C1-large artery, C2-small artery) were detected by using HDI DO-2020. Results: IMT and diameter of the CCA of carotid artery plaque group was markedly increased, compared with control group and non-carotid artery plaque group (P 0.01), but there was no statistical difference between control and non-carotid artery plaque groups (P 0.05). Both C1 and C2 among three groups were significantly different (P 0.05). C2 was negatively associated with IMT of CCA and there was no correlation between C1 and IMT of non-carotid artery plaque group. Both C1 and C2 were negatively associated with IMT in carotid artery plaque group. Conclusions: The linear relation is existed between IMT of CCA and vascular compliance, it should be indicators in the diagnosis of early atherosclerosis by combined using.
Intima-media thickness
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Bradycardia is a slow heart rate, meaning under 60 beats per minute. Generally, it is normal to have a slower heart rate when you’re resting and sleeping, and in some people, particularly healthy young adults and trained athletes. A slow heart rate is frequent under several circumstances and does not require treatment unless it causes symptoms. Bradycardia belongs to the category of “palpitation” in Traditional Chinese Medicine (TCM). Two aspects of the pathogenesis of palpitation are deficiency and excess. Benefiting qi, nourishing yin and activating blood circulation are the general principles in treatment. In this article is presented a case of 48 years old man with bradycardia and with symptoms of chest pain and fatigue. Before coming to the TCM center and generalizing acupuncture therapies, his heart rate was 48 bpm, saturation 94% and blood pressure 150/90. Аfter 3 acupuncture treatments, his heart rate has normalized and is 76- 77 bpm. The patient has a previous history of hypothyroidism, but for the last 4 years, the hormones have been within reference values and he does not take medication at all. He is not an athlete and is not physically active. Acupuncture, as a part of TCM, is an effective treatment and gives very satisfying results in these kinds of conditions.
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The common carotid artery (CCA) usually divides into the internal carotid artery (ICA) and the external carotid artery (ECA). We present an extremely rare case of a non-bifurcating carotid artery through which intra-arterial chemotherapy for laryngeal cancer was administered. The CCA angiogram, as well as ultrasonographic evaluation of the carotid arteries, demonstrated a non-bifurcating CCA that subsequently constituted the ICA. Furthermore, several branches normally given off by the ECA arose directly from the single carotid artery. Superselective intra-arterial infusion of cis-diamminedichloroplatinum (II) (CDDP) was subsequently performed.
External carotid artery
Arterial wall
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Abstract The response of heart rate to acute 1,1,1-trichloroethane (1,1,1-TCE) inhalation and its mechanism via the autonomic nervous system were studied in anesthetized dogs in acute inhalation experiments. Concentrations of 1,1,1-TCE in inspired air of 1.32 ± 0.14% (mean ± S.E.) increased heart rate, but 2.79 ± 0.24% decreased heart rate. Opposite reactions of heart rate were observed when blood pressure decreased to 70–80 mm Hg following inhalation. Moreover, both tachycardia from relatively low concentrations and bradycardia from higher concentrations were blocked by pre-administration of adrenergic beta blocker, but were only slightly affected by vagotomy. It is suggested that both tachycardia and bradycardia following 1,1,1-TCE inhalation may be controlled by the sympathetic nervous system.
Sympathetic nervous system
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This study evaluated the effectiveness of glycopyrrolate (0.005 or 0.01 mg/kg body weight (BW)) in anesthetized dogs (n = 40) for reversal of bradycardia (< 65 beats/min). Following random intravenous (i.v.) treatment, heart rate was determined at 5 min and, if it was < or = 70 beats/min, the lower dose was repeated. A 2-way analysis of variance considered dose and animal size (< or = 10 kg, > 10 kg) effects (P < 0.05). Glycopyrrolate produced a significant increase in heart rate and infrequent tachycardia (< or = 150 beats/min), which was not dose-related. The size of the dog produced a significant effect on baseline heart rate (higher in small), rate following the first dose (lower in small), and requirement for retreatment (47% in small, 13% in large). In a separate group of anesthetized dogs (n = 20), the blood pressure effect of glycopyrrolate (0.01 mg/kg BW, i.v.) treatment of bradycardia (65-85 beats/min, weight-adjusted) was studied. A significant increase in systolic, diastolic, and mean blood pressure was produced. In conclusion, the effective dose of glycopyrrolate treatment is size-related and produces a beneficial effect on blood pressure.
Glycopyrrolate
Increased heart rate
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Comparison of blood pressures obtained by femoral and common carotid artery cannulation has shown that in the rat anaesthetized with Nembutal an increase in blood pressure occurs after neck surgery and common carotid artery cannulation.
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Biotelemetry transmitters were surgically implanted in the abdominal cavity of 12 mature swamp rabbits, Sylvilagus aquaticus, to monitor the heart-rate response to forced and voluntary diving. Atropine and propranolol were used to investigate autonomic control of heart rate. Each untreated rabbit showed a marked (- 79%) bradycardia when forcefully submerged for 10 s. Mean heart-rate values during predive, dive, and recovery were 213 ± 12.6, 44 ± 7.5, and 206 ± 14.9 beats/min (X̅ ± SE), respectively. Onset of bradycardia occurred rapidly at a rate of - 169 (beats/min)/s. The bradycardia was fully established during the first second of the dive. A marked sinus arrhythmia often occurred during forced diving. Recovery occurred at a rate of 206 (beats/min)/s during the first second, then dropped to 15.9 (beats/min)/s. Propranolol reduced bradycardia to - 65%, although dive values were not significantly different from control diving. Mean values were 146 ± 11.2, 51 ± 9.5, and 130 ± 11.9 beats/min, respectively. In propanolol experiments, onset was rapid (95 beats/min)/s, but recovery rate was reduced to 35 (beats/min)/s during the first second and to 7.4 (beats/min)/s thereafter. Atropine abolished diving bradycardia. Diving increased parasympathetic tone from 29.8% to 75.5% and reduced sympathetic tone from 46.2% to 35.1%. Together, these data suggest that both portions of the autonomic nervous system are important for forced diving bradycardia. Parasympathetic activity initiates and maintains the response. Removal of the sympathetic tone enhances the response, as evidenced by the propranolol experiments. Sympathetic activity is necessary for rapid recovery. Four rabbits were trained to voluntarily dive for a food reward. Voluntary dives lasted 4 s. Mean heart-rate values were 197 ± 10.1, 211 ± 19.3, and 243 ± 15.9 beats/min. No bradycardia was observed during voluntary diving, suggesting that the bradycardia associated with forced diving is a response to fear and not submergence.
Vagal Tone
Reflex bradycardia
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