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PubMed1984

[An experimental study on neurotoxicity of 2,5-hexanedione. Visual and somatosensory cortical evoked potentials in rats].

In order to clarify the effects of 2,5-hexanedione (2,5-HD) on the central nervous system, the somatosensory evoked potentials (SEP) and the visual evoked potentials (VEP) were experimentally studied. Eight male rats (Jcl-Wistar) were given subcutaneously 300 mg/kg/day of 2,5-HD five days a week for three weeks. Another eight male rats group served as the control. One week after ending the administration, the SEP and VEP of rats were measured under artificial respiration using bipolar and monopolar recording methods. The caudal nerve conduction velocities (C-NCVs) were also measured before the administration was begun, and weekly during the experiment, using Ono's method. Significant findings observed in the 2,5-HD administered group in comparison with the control group were as follows: delayed latencies in P1 and N1 components of VEP, reduced amplitude between N1 and P2 components of VEP and decreased caudal nerve conduction velocities. It was also observed that latencies of SEP components of the 2,5-HD administered group tended to prolong in spite of shorter conducting length. Alterations of VEP and a tendency of prolongation in latencies of SEP components were considered to be dysfunctions of the visual and somatosensory afferent pathway attributable of 2,5-HD. The present experiments suggest that for further understanding of the effects of 2,5-HD, on the central nervous system, it is necessary to utilize more sophisticated techniques which can quantitatively detect neurophysiological changes in the ascending tract from the periphery to the cortex.

Animals↗
PubMed2002

Neonatal pneumonia caused by Trichomonas vaginalis.

The authors present two cases of newborn babies infected by Trichomonas vaginalis (hereafter referred to as T. vaginalis) and suffering from severe congenital breathing difficulties and needing artificial respiration. Microscopic examination of the tracheal discharge revealed characteristically moving, flagellated, pear-shaped unicellular organisms. Cultures on CPLM medium proved the presence of T. vaginalis. During pregnancy the mothers' clinical status was negative and both of them mentioned leukorrhoea of changing intensity. They were regularly involved in antenatal care. The infection caused by T. vaginalis could be detected in the two mothers later by culture procedures.

Animals↗
PubMed2000

Effect of constant and intermittent vagal stimulation on the heart rate and heart rate variability in rabbits.

To examine whether the high-frequency (HF) component of heart rate variability (HRV) reflects fluctuation or tonic level of vagal outflow, we investigated the effects of vagal efferent nerve stimulation (VS) on the heart rate and HRV in anesthetized open-chest rabbit under artificial respiration at a rate of 52 breaths/min (0.86 Hz). A power spectral analysis was performed at baseline and during VS (stimuli at 2 ms, 1-10 V and 5-25 Hz). VS was applied using two different patterns. The first was constant VS; continuous stimulation at graded frequency or voltage to simulate changes in the level of vagal "tone." The second pattern was intermittent VS; stimulation at 0.5 Hz of on-off cycle to simulate fluctuations in vagal efferent activity. The power spectrum at baseline showed a single narrow component at 0.86 Hz, identical to respiration rate. Both the constant and intermittent VS prolonged RR interval. The amplitude of the component at 0.86 Hz remained unaffected by either the constant or intermittent VS, whereas the latter evoked a distinct narrow component at 0.5 Hz, reflecting the on-off cycle of intermittent VS. Our results suggest that the HF component of the power spectrum of HRV measures the magnitude of fluctuations of vagal input associated with respiratory modulation.

Action Potentials↗
PubMed1989

Neurotransmitter effects on inhibitory burst neurons in the cat.

The present experiment was designed to determine which neurotransmitter influences the burst pattern in the firing of the inhibitory burst neurons (IBN) during vestibular nystagmus. Cats were anesthetized with ether and mounted in a stereotaxic apparatus on a turntable, implanted stimulation electrodes, removed occipital bone and aspirated the vermal part of cerebellum. After the operation ether was discontinued. The recordings took place with the cats in an alert condition created by upper cervical cord transsection, artificial respiration and local anesthesia by infiltrating 0.5% lidocaine into the semilunar ganglions every two hours. We also employed iontophoretic application of the various drugs: GABA, muscimol, glycine, serotonin (5-HT) and bicuculline through seven-barrelled glass micropipettes. GABA or muscimol did not influence nystagmus rhythm, but both chemicals caused strong suppression of burst activities in IBN. Since this inhibitory effect of GABA was suppressed by the simultaneous application of bicuculline, IBNs appear to be controlled by GABAA receptor. Glycine and 5-HT did not change the firing pattern of IBN. Application of bicuculline itself caused an increase of tonic discharges of IBN. These findings suggest that IBN receive inhibitory impulses from the higher GABAergic neurons.

Animals↗
PubMed1994

Ultrastructure of the epithelial cells of the endolymphatic duct in the rat.

The ultrastructure of the epithelial cells of the endolymphatic duct in the rat is described, following vascular perfusion-fixation of live, anaesthetised and artificially respirated animals. The animals were fixed by means of a pressure feed-back controlled peristaltic pump and an isotonic perfusate-fixative containing glutaraldehyde and Dextran. The endolymphatic duct was isolated by microdissection after the perfusion-fixation, to omit the step of a demineralization procedure. The proximal, intermediate and juxta-saccular parts of the endolymphatic duct were embedded, sectioned and studied separately in the electron microscope. Postfixation in a solution containing OsO4 and potassium ferricyanide revealed a well-developed tubulo-cisternal endoplasmic reticulum (TER), not previously described. Serial sectioning and computerized three-dimensional reconstruction demonstrated a continuity of the TER through the cell from subsurface cisterns abutting on the apical cell membrane to subsurface cisterns abutting on the basolateral cell membrane. The TER resembles that found in solute transporting epithelia, e.g., renal proximal tubule, gall bladder, small intestine and choroid plexus. A fluid resorptive capacity of the epithelial cells of the endolymphatic duct is compatible with the fine structure revealed in the present study. Epithelial cells in the juxta-saccular part of the duct display morphological indications of a secretory activity; furthermore, multivesicular bodies were observed in the epithelial cells throughout the endolymphatic duct.

Animals↗
PubMed1994

Cochlear flux motion and arterial pressure reduction in guinea pig.

Vasomotion, as a fundamental phenomenon of microvessels, exists in the cochlea of guinea pig. In the current study, the vasomotion and its relation to arterial pressure reduction was studied in the guinea pig cochlea, using laser Doppler flowmetry (LDF). Blood pressure (BP) in 25 guinea pigs was manipulated by a mechanical occluder placed around the descending aorta or the inferior vena cava. Before thoracotomy and artificial respiration, BP was 55.5 +/- 10.9 mmHg and no flux motion occurred. Vasomotion became evident when BP was significantly lower (28.2 +/- 7.2 mmHg) than the mean BP after thoracotomy (37.3 +/- 8.3 mmHg) (t = 4.1536, p < 0.05). Vasomotion appeared during both continuous hypotension and brief BP decreases caused by mechanical occlusion. During periods of continuous flux motion, both increase and decrease in BP could weaken or abolish it. The pressure provoking the vasomotion was different for each animal but the pressure range for a given animal was relatively stable. Mean frequency and amplitude of flux motion were 3.8 +/- 0.6 cycles per min and 20.8 +/- 7.1% of the baseline. A negative linear relationship was found between amplitude and frequency. Oscillations of LDF signal indicate that there is a synchronization of contraction and relaxation of cochlear microvessels or of the larger supplying vessels to the cochlea. Manipulation of BP possibly initiates the fluctuating change in vascular tone by influencing the activity of pacemaker or feedback mechanisms of cochlear vascular smooth muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1977

Severe toxicity and lethality in some monkeys following chronic administration of levo-alpha-acetylmethadol (LAAM).

Recurrent episodes of mild to severe opiate-like toxic effects were observed in 3 of 18 monkeys maintained on 2 mg/kg p.o. dose of LAAM on alternate days 3 times a week for up to one year. Despite antagonist administration and artificial respiration, the final toxic reaction in 3 LAAM sensitive monkeys progressed rapidly to cardio-respiratory arrest and death 3, 6, and 12 months after LAAM treatment. The blood chemistry and hematology were not significantly altered during chronic LAAM administration. Necropsy did not reveal any aberrant gross, histological or neuropathological features other than pulmonary edema. Differential rates of formation and elimination of active metabolites of LAAM may play a significant role in this potentially lethal toxicity. These findings may have important clinical implications for LAAM maintenance treatment programs.

Animals↗
PubMed1996

Naloxone--for intoxications with intravenous heroin and heroin mixtures--harmless or hazardous? A prospective clinical study.

BACKGROUND: Naloxone is standard medication for the treatment of heroin intoxications. No large-scale studies have yet been carried out to determine its toxicity in heroin intoxications. METHODS: We have undertaken an investigation as to the frequency, type and degree of severity of complications attributable to naloxone administration. Subjects treated between 1991 and 1993 with naloxone for intravenous drug intoxications were prospectively evaluated. MAIN OUTCOME MEASUREMENTS: Development of ventricular tachycardia or fibrillation; atrial fibrillation; asystole; pulmonary edema; convulsions; vomiting; and violent behavior within ten minutes after parenteral administration of naloxone. RESULTS: Six of 453 intoxicated subjects (1.3%; 95% confidence interval 0.4%-3%) suffered severe adverse effects within ten minutes after naloxone administration (one asystole; three generalized convulsions; one pulmonary edema; and one violent behavior). After the ten minute period, no further complications were observed. CONCLUSIONS: The short time between naloxone administration and the occurrence of complications, as well as the type of complications, are strong evidence of a causal link. In 1000 clinically diagnosed intoxications with heroin or heroin mixtures, from 4 to 30 serious complications can be expected. Such a high incidence of complications is unacceptable and could theoretically be reduced by artificial respiration with a bag valve device (hyperventilation) as well as by administering naloxone in minimal divided doses, injected slowly.

Adolescent↗
PubMed1992

[Neuropathological study of amyotrophic lateral sclerosis in relation to aging].

It has been assumed that amyotrophic lateral sclerosis (ALS) involves precocious senility as one of its pathogenetic aspects. The authors studied 55 autopsied cases of ALS in relation to age at death, ranging from 42 to 86. The materials consisted of 8 cases in the fifth decade, 8 in the sixth, 20 in the seventh, 12 in the eighth, and 7 in the ninth. The total duration of illness ranged from 6 months to 14 years. The most distinct relationship was observed in the anterior horn lesion of the cervical enlargement which became less severe with advancing age, irrespective of the length of illness. Fifth decade cases showed marked atrophy with severe neuronal loss and fibrillary gliosis in the anterior horn, while those in the ninth decade showed slight changes which were similar to age-matched controls. On the other hand, pyramidal tract degeneration did not show any correlation to age at death or to length of illness. Pyramidal tract degeneration was found in all younger age group cases, being always severe. In the older age groups, however, the degeneration varied extremely in degree from case to case. Some cases showed severe degeneration comparable with that in the younger age groups, while the others had no findings suggesting degeneration. In addition, cases on artificial respirators had a longer duration of illness, and more marked degeneration in the anterior horn, irrespective of age. Our study did not reveal that senile changes including senile plaques and neurofibrillary tangles were more marked in ALS cases. No clinicopathological correlation with dementia was recognized.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1977

Pneumocephalus secondary to cerebrobronchial fistula formed by a ventriculoatrial shunt. Case report.

A case is presented in which the atrial tip of a ventriculoatrial shunt formed a fistulous connection with the bronchial tree in a child. This resulted in acute bronchopneumonia, pneumocephalus, and ventriculitis. Pneumocephalus was created by an artificial respirator forcing air along the shunt tract during treatment of bronchopneumonia. Sudden death was related to transtentorial herniation. The diagnosis of a cerebrobronchial fistula should be entertained in shunt patients with respiratory distress and radiographic pulmonary densities unresponsive to antibiotics.

Bronchial Fistula↗
PubMed1977

Studies of methods for in situ observation of gastric motility in domestic turkeys.

The normal gastroduodenal contraction cycle of turkeys is believed to be controlled and coordinated by the myenteric plexus which lies just under the serosa of the muscular stomach. Methods which would permit direct application of chemical and physical stimuli to these gastric nerves were studied in intact and decerebrate turkeys using both radiographic and direct observations to monitor contraction cycles. In intact turkeys, general anesthetics (sodium pentobarbital, halothane; and ketamine hydrochloride) inhibited gastric motility. A local anesthetic (lidocaine hydrochloride) injected into the skin and abdominal muscles caused a depression of motility. In both intact and chronically decerebrate turkeys laparatomy (after local anesthetic in intact birds) and a neuromuscular blocking agent (gallamine triethiodide) also depressed gastric motility. Motility was slightly reduced by artificial respiration and exposure of the serosal surface of the stomach and intestines to air via an abdominal fistula.

Anesthesia, General↗
PubMed2001

[Fatal pulmonary embolism developing after tympanoplasty: a case report and incidence of pulmonary embolism at Toyooka Hospital].

We report a case of fatal pulmonary embolism (PE) developing after tympanoplasty. A 69-year-old woman underwent type III tympanoplasty for a middle ear cholesteatoma under general anesthesia. Operating time was 3 hours 27 minutes and anesthesia lasted 5 hours 9 minutes. The next morning, 14 hours 5 minutes after returning to the recovery room, the patient lost consciousness while getting out of bed. Although consciousness recovered transiently, she went into shock with cardiopulmonary arrest. Heart beat was regained after resuscitation with artificial respiration and cardiac massage, but her blood pressure was unstable. Echocardiography revealed right ventricular overload and pulmonary hypertension. Because PE was suspected, thrombolytic therapy was conducted to stabilize hemodynamics. Enhanced computed tomography (CT) of the chest showed bilateral pulmonary thromboembolism. The patient died of hypoxic encephalopathy 23 days after PE onset. We have seen 40 cases of PE at our hospital in the last 70 months. Five patients developed PE after surgery with a postoperative occurrence rate of 0.03% (5/16, 277), and 3 of them died. Enhanced CT in 19 of 21 cases (90.5%) before or just after the start of therapy for PE was useful in establishing the diagnosis. Although PE is rare in the field of otolaryngology and head and neck surgery, it may develop rapidly after any type of surgery resulting in a fatal outcome. It is thus important to establish diagnosis early and prevent such serious complications.

Aged↗
PubMed1991

Treatment of acute organophosphate poisoning.

The biochemistry and pharmacology of poisoning by organophosphorus esters and carbamates are outlined and methods of diagnosis and treatment are discussed. Treatment consists of reduction of exposure by decontamination, induction of vomiting or gastric lavage; pharmacological treatment with atropine and oximes (pralidoxime and obidoxime); and supportive treatment with artificial respiration and centrally acting drugs such as diazepam. The sequence of treatment depends solely on the severity of poisoning.

Antidotes↗
PubMed2003

[Guidelines for revised cardiopulmonary resuscitation--basic life support].

Basic life support(BLS) does not require any special instruments or drugs, and its skills can be understood and performed easily by the lay person. The main goal of cardiopulmonary resuscitation(CPR) for the victims of cardiac pulmonary arrest(CPA) is not only restoration of cardiopulmonary function but also return to their previous life. An early bystander CPR plays a pivotal role to achieve this target. When encountering an unconscious person, emergency medical systems(EMS) such as calling 119 must be activated immediately. As the next step, cardiopulmonary condition status has to be determined after assurance of airway patency. When there are no signs of breathing or pulse, BLS consisting of artificial respiration and/or chest compression must be started immediately and continued until EMS staffs arrive. In this article, the details of the revised guidelines for BLS by the American Heart Association are described. Current CPR education for pre- or early post-graduate medical students in our institution is reported.

American Heart Association↗
PubMed1976

[Indications for the reconstruction of the unstable thorax due to serial rib fractures and respiratory insufficiency].

Because of the impending danger of bronchopneumonial infection caused by hospital germs we consider it of utmost importance in the care and treatment of patients with instable thorax to shorten the period of intubation and artificial respiration. By stabilizing 3 or 4 chozen ribs within the flailing chest wall, we found it possible to significantly reduce the period of intubation, intensive care and hospitalisation. The splinting of several ribs individually by introducing socalled "Rehbein plates" into the medullary cavity of those in question proved to be a trustworthy method in achieving this goal.

Cross Infection↗
PubMed1976

Lethal effect of the serotonin-xylocaineR association in ganglion-blocked rats.

In rats anestetized with urethane and under ganglionic blockade by hexamethonium (20 mg/kg, i.v.), the i.v. injection of serotonin (60 mug/kg) determined apnea, ECG alterations and a brief hypotensive response which is similar to that as elicited when 5-HT is given to intact rats. During the hypertension which follows that initial response, apnea is still present along with more severe ECG changes. After that, blood pressure falls into a prolonged hypotension, which is invariably accompanied by death. Neither norepinephrine, nor respiratory analeptics (CoramineR, RemeflinF) were able to prevent the fatal outcome. Only artificial respiration was found to be useful in some instances. It was concluded that the association serotonin plus lidocaine becomes lethal when given to ganglion-blocked rate, and this toxic effect can be ascribed mainly to the respiratory depressor activity of the drugs.

Animals↗
PubMed1999

Operational use and patient monitoring in a multiplace hyperbaric chamber.

Multiplace hyperbaric chambers can be used to deliver patient care with enormous flexibility. Standard critical care techniques, such as mechanical ventilation, endotracheal suctioning, hemodynamic monitoring, blood gas measurement, and emergency therapy such as cardiopulmonary resuscitation, including defibrillation and cardioversion, can all be performed inside a multiplace chamber. The multiplace chamber can be considered an extension of the intensive care unit. This flexibility is accompanied by increased complexity of chamber operation. Careful attention must be paid to minimization of fire hazards and maintenance of a safe chamber atmosphere. Although life support apparatus can easily be taken inside the chamber and will usually work under hyperbaric conditions, care must be given to facilitate the benefits to the patient of hyperbaric oxygen treatment in the face of potential risks associated with rapid changes in environmental pressure and the partial pressures of the component gases.

Barotrauma↗
PubMed1985

In the Matter of Claire C. Conroy, No. A-108 (N.J. Jan. 17, 1985).

Life-sustaining treatment, such as artificial respiration, nutrition, or hydration, may be withheld or withdrawn from a competent patient who declines such treatment. Such treatment may also be withheld or withdrawn from an incompetent patient when it is clear that the patient would have refused the treatment under the particular circumstances. In the absence of evidence of what the patient would have done in the specific situation, life sustaining treatment or support may be withdrawn from an incompetent person when it is clear that the treatment would merely prolong suffering. No such decision may be based upon an assessment of the personal worth or social utility of an incompetent patient's life.

Aged↗