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Biomedical subjects

H Chai

Publications and source records attributed to H Chai.

At least 55 records · Page 3Linked to original sources
PubMed1992

[Effects of calcium channel blocker verapamil on hippocampal kindled seizures induced by coriaria lactone in rabbits].

Eighteen fully kindled rabbits, whose epilepsy had been produced by intrahippocampal (i.h.) injections of 2 microliters of diluted solution containing 0.32 or 0.55 micrograms of coriaria lactone (CL), were separated into three groups. One of them was used as the control group. For seizure, all animals were given CL (0.6-1 micrograms/2 microliter i.h.). Ten minutes later, the verapamil (VR) group of six rabbits was treated with VR (1.5 or 2 mg/kg i.m. 2.5 or 5 micrograms/2 microliters i.h.); the normal saline (NS) group (six rabbits) received 0.8 ml/kg (i.m., in the same volume as that of the VR 2 mg/kg injection) or 2 microliters (i.h.) of NS; the control group of six received neither VR nor NS. The experiments were made once every eight days. Hippocampal EEGs of all animals were recorded by telemetric method and their behavior after injection was observed continuously in 4-7 hours. The results of the experiment indicated that the i.h. administration of 2.5 or 5 micrograms/2 microliters of VR is effective on hippocampal kindled seizures induced by CL in rabbits, but the curative effects of the i.m. administration of 1.5 or 2 mg/kg of VR were less notable than those of the i.h. administration.

Animals↗
PubMed1992

[Observation of paired-pulse depression in CA1 region of hippocampal slices from coriaria lactone-kindled rats].

Paired-pulse depression (PPD) technique was used to investigate the potency of recurrent synaptic inhibition mediated by GABA in area CA1 of 54 hippocampal slices from coriaria lactone (CL)-kindled and control rats. When paired stimuli were sent to the axon of CA1 pyramidal cell and Schaffer collaterals, the effect of population spike PPD lasted about 40-60ms; no significant change was observed on PPD potency between kindled and control groups (P = 0.06, 2-way ANOVA). The results indicate that the GABA-ergic synaptic inhibition seemed not to play a key role in the maintenance of the chemical kindling induced by CL.

Animals↗
PubMed1992

[Ultrastructural observation of SC1001-sodium on brain neurons kindled seizures by coriaria lactone in rabbits].

The ultrastructural changes of hippocampus and cerebral cortex neurons were derived from the rabbits kindled by coriaria lactone and from the kindled rabbits after treatment with SC1001 Na. The results of experiment showed that the hippocampus and cerebral cortex neurons in the kindled group had some degenerative changes, such as the swelling mitochondria, dilated rough endoplasmic reticulum and Golgi complexes when the injuries of neurons were not serious, but the seriously injured neurons were subjected to rupture of the cell membrane and solution of most organella, with only a small amount of degenerative organella. In the group treated with SC1001 Na, the ultrastructure of brain neurons demonstrated a tendency of recreation to normal which showed that SC1001 Na had cured many of the degenerative brain cells. This suggested that active treatment is very important for the epileptic patients.

Animals↗
PubMed1991

Metaproterenol (Alupent) metered dose inhaler in children 5-12 years of age.

This multiclinic study was performed to evaluate the safety and efficacy of metaproterenol sulfate (Alupent) metered dose inhaler in children with asthma ages 5 to 12 years. A total of 268 children completed this study according to the protocol, having received either metaproterenol or placebo for 30 consecutive days. Full spirometric testing was done pre- and postdose on Days 1 and 30 for a total duration of 6 hours on each day. The results showed that metaproterenol was consistently superior to placebo in all pulmonary function parameters measured on Days 1 and 30. This difference was statistically significant for peak values and areas under the curves for both FEV1 and FEF25-75%. There were no significant side effects noted. We conclude that metaproterenol metered dose inhaler is safe and effective in the treatment of asthma in children ages 5 to 12 years.

Administration, Inhalation↗
PubMed1991

[Observation of enzyme histochemistry and ultrastructure of brain in kindling rats with epilepsy induced by intraperitoneal injection of coriaria lactone].

Kindling model of epilepsy induced by intraperitoneal injection of Coriaria lactone (CL) was used in the experiment. The dose of CL was 1.25 mg/kg. Thirty rats in various periods of kindling were killed and the materials of cerebral cortex, hippocampus and cerebellum were drawn. The enzyme activities of AchE, NADHD, CCO, LDH, SDH, AcP, ANAE and AkP of these areas were observed with enzyme histochemical techniques. In another three kindled rats, two blank control rats and two NS control rats, the ultrastructure of neurons in hippocampus were observed. The results of experiments showed an increased activity of enzymes related to saccharometabolism and energy metabolism, indicating that the metabolism of brain in rats was increased by repeated kindling seizures. The mechanism of kindling seizure induced by CL may be related to inhibitory effect of CL on AchE activity of brain. The degeneration damage of brain neurons in kindled rats may result from using CL for a long time.

Acetylcholinesterase↗
PubMed1991

[Effects of SC1001-sodium on hippocampal kindled seizures by coriaria lactone in rabbits].

Healthy rabbits weighing 1.7-2.4 kg were used. According to Sawyer's atlas the stainless steel cannula and recording electrode were implanted into the left hippocampus of each animal. The kindling experiments were started one week after the surgical operation. For kindling, all animals received injection of 2 microliters of diluted solution containing 0.55 or 0.32 microgram of coriaria lactone (CL) every second day, through the single stainless steel cannula previously implanted in the hippocampus. Hippocampal EEG of all the animals was recorded by telemetric method and the behavior of them was observed at the same time. Eighteen fully kindled rabbits were separated into three groups. The SC1001 Na group of six rabbits was treated with SC1001 Na (100 mg/kg, i.m.), the PB Na group (six rabbits) received phenobarbital Na (30 mg/kg, i.m.), and the control group of six was treated with placebo (normal saline, i.m., in the same volume as that of the SC1001 Na injection); injections were administered once a day for two courses of treatment (one course of treatment was 1 week). The results of the experiment indicated that SC1001 Na (100 mg/kg) had certain effects on hippocampal kindled seizures induced by CL, but its curative effects were not more notable than those of PB Na (30 mg/kg).

Animals↗
PubMed1991

[Kindling effect in models of epilepsy induced by clinrats].

In order to create chemical kindling effect model of epilepsy, fifty-six adult male SD rats were used in this experiment, and randomly divided into five groups. An intramuscular injection of various subthreshold dose of CL (0.50, 0.75, 1.00, 1.25 mg/kg) was given repeatedly per 3.5 days in the I-IV groups, V group received injections of normal saline of the same volume as control. ECoG and EHG were recorded by telemetric method through electrodes chronically implanted in the cortex and hippocampus. The behavior of them was observed at the same time. The results of experiments showed that: 1. CL can lead to the typical behavior, ECoG and EHG of epilepsy. So it is an effective chemical kindling agent of causing epilepsy, and hippocampus was more than cortex to CL. 2. The relationship between the seizure stages induced by CL various dose groups and the mean injection times had a linear correlation through linear regressive processing (r value: 0.9276-0.99732). The difference comparison of linear regressive intercept of various groups was significant (P less than 0.05), respectively. It is indicated that the more the dose of CL increase, the less the injection times of reaching seizure stages. 3. 24 rats of the experimental groups 46 rats had reached kindling criterion through 40 times injection of CL. The difference comparison between I, II and III, IV groups of kindling rats was quite significant (P less than 0.01), respectively. 4. The mean persistence time of all kindled rats was 113.42 days. The longest persistence time of them was 224 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Variation of cAMP in cerebral cortex and hippocampus in seizure mice induced by coriaria lactone].

To study the relationship between cAMP and epilepsy, we investigated the effects of coriaria lactone (CL) on the levels of cAMP in cerebral cortex and hippocampus. Fifty normal WC1 mice were divided into 5 groups. All groups were injected with CL (2.5 mg/kg, i.m.), except the control group which was injected with NS. The concentrations of cAMP were measured after the animals had been immersed in liquid nitrogen to die at different phases of seizure development induced by CL (before seizures, in mild seizures, during severe seizures, and after severe seizures). The results indicated that the levels of cAMP in both cerebral cortex and hippocampus were significantly increased (1.73-fold and 1.33-fold) in severe seizure, and they continuously increased (1.85-fold and 1.45-fold) after severe seizures. On the other hand, no changes of cAMP were observed in mild seizures and before seizures. These data suggested that accumulation of cAMP is probably the result of seizure activity rather than the cause of seizure.

Animals↗
PubMed1990

[A kindling model of epilepsy induced by intraperitoneal injection of coriaria lactone in rats].

Fifty adult male Sprague-Dawley rats were divided into five groups. Intraperitoneal injections of various doses of coriaria lactone (CL, 0.75, 1.25, 1.75, and 2.0 mg/kg) and normal saline were given respectively per 2 days. The behavior of the rats was observed and the ECoG was recorded by telemetric method. The results of experiments show that a kindling model of epilepsy can be established by intraperitoneal injection of CL in rats. This chronic experimental model is of value for application because it is easily established and the rate of being kindled is relatively high, but the mortality is low, and the kindling effect can last well. The model can avert the pathological change caused by artificial injury to brain, so it is advantageous to the research on neurochemistry and ultrastructure. In our experimental condition, it is optimal to select 1.25 mg/kg or 1.75 mg/kg as the dosage of CL for establishing kindling model.

Animals↗
PubMed1990

[Coriaria lactone-induced epileptiform activity in the hippocampal slices of rat].

Coriaria lactone (CL) is an active constituent of a medicinal herb used as psychosolytic in traditional Chinese medicine. Recently it has been found that CL appears to act as a convulsant agent. Subsequently both acute and chronic epilepsy models caused by CL have been established successfully. In order to observe further the epileptogenic effects of CL in vitro, the hippocampal slice technique was used in experiments with 36 slices. The results are as follows: Addition of CL to the perfusion bathing the slices of rat hippocampus increased evoked-response in body layer of CA1 in a dose-dependent manner, and induced epileptiform burst. CL augmented population spike of CA1 pyramidal neurons triggered by either orthodromic stimulus (through synapses) or antidromic stimulus (direct effect on the axon of CA1 pyramidal cells) without alteration of presynaptic fiber volley and field-EPSP, and there was no significant change in latency of burst. Finally GABA had a weak effect on CL-induced epileptiform activity. These observations suggest that CL probably has a direct effect on the soma of pyramidal neurons, CL-induced epileptiform burst may be a result of altering the innate capacity of burst and increasing the intrinsic excitability of pyramidal cell membranes.

Animals↗
PubMed1989

[A fast determination of serum bilirubin with the interference from hemolysis and turbidity by three wavelength spectrophotometry].

In determination of bilirubin in serum by means of color reaction when hemolysis and turbidity are present, the reliability of the measurement is decreased by the interference from hemoglobin and other turbidities. Direct measurement of bilirubin in serum by three wavelength spectrophotometry at 500 nm, 450 nm and 370 nm instead of by color reaction, provides a fast, semi-micro and accurate way without the use of any reagents. Besides the rise of the baseline by blood cells and turbidities can be corrected without the consideration of hemolysis. Under the given experimental condition, the mean recovery is 96.3 +/- 2.41% (n = 6), coefficient of variation (CV) is 4.0%.

Bilirubin↗
PubMed1988

Cat- or dog-induced immediate and late asthmatic responses before and after immunotherapy.

To assess the effect of specific immunotherapy (IT) on the immediate and late asthmatic responses induced by cat or dog extract bronchial provocation testing, we studied seven cat-sensitive and six dog-sensitive subjects with asthma. Among the cat-sensitive subjects, two of three subjects displaying only an immediate asthmatic response before IT lost the response after 3 months of IT with cat extract, whereas only one of four subjects with the dual (immediate and late) asthmatic responses had ablation of such responses (no significance for the one-tailed test). Three subjects had worsening of the immediate response after IT. Among dog-sensitive subjects with asthma, three of five subjects with only an immediate response demonstrated an ablation of the immediate response, whereas the one subject who was the only subject with a dual response before IT lost the dual response after dog-extract IT (p value of 0.005 on one-tailed test). Immediate systemic side effects, including one episode of anaphylaxis, occurred on seven occasions of 326 injections with cat extract compared to only one episode of rhinitis of 289 injections with dog extract.

Adult↗
PubMed1987

Effects of inhaled lidocaine on exercise-induced asthma.

Experiments were performed to determine if stimulation of afferent nerve endings in the respiratory mucosa plays a major role in the initiation of exercise-induced asthma. Five asthmatic subjects were studied in two sessions of 10 min treadmill exercise using an identical workload. In the control session the subjects were exercised without treatment; in the other session aerosol lidocaine (1.5 mg/kg) was inhaled from residual volume to total lung capacity before exercise was started. Pulmonary function tests were measured (1) to obtain baseline values before the aerosol inhalation or exercise was commenced, (2) 2-3 min after completion of lidocaine inhalation, and (3) 4 min after termination of exercise. In the control session the mean postexercise forced expiratory volume in 1 s (FEV1) and the mean forced expiratory flow during the middle half of forced vital capacity (FEF25-75%) were decreased to 61 and 44% of the baseline values, respectively. Similarly, with the lidocaine treatment the post-exercise FEV1 and FEF25-75% were decreased to 54 and 44% of the baseline values, respectively. These data indicate that the afferent nerves in the respiratory mucosa may not play a critical role in the development of exercise-induced asthma.

Administration, Inhalation↗
PubMed1986

Mnemonic effects of asthma medication in children.

Asthmatic children receiving theophylline or steroid-theophylline combination therapy and normal nonasthmatics were given tests of visual retention and paired-associate learning. The performance of children receiving combination therapy was significantly worse than that of the nonasthmatics 6-8 hours after receiving steroid medication, but not 22-24 or 46-48 hours after medication. Children receiving theophylline alone did not differ from nonasthmatics on these tasks. These observations suggest that steroid-inclusive medication regiments can affect cognitive performance.

Adolescent↗
PubMed1986

A standard method of intermittent inhaled therapy via a jet nebulizer.

Current methods of inhaled therapy using gas-propelled nebulizers lack standardization. The frequent use of nebulized therapy in a continuous flow may be the major reason for the inconsistency of the actual fraction of nebulized drug delivered to the patient. In an effort to achieve consistency in the amount of drug delivered to the patient, we evaluated an intermittent system of nebulized therapy, using a fingertip controlled nebulizer, in 18 adolescent asthmatics. This mode of delivery was found to be highly efficient, providing a nebulized fraction of more than 70% of the initial volumes used (0.75 to 2.6 mL). Initial volumes of 0.9 mL and above were equally efficacious, indicating no further benefit of using higher volumes. Nebulized fractions were found to be highly consistent from one patient to another (+/- 1 SD of 14.1%). We conclude that control of the actual dose delivered to the patient can be best achieved through an intermittent mode of delivery.

Adolescent↗
PubMed1986

Albuterol protects against exercise-induced asthma longer than metaproterenol sulfate.

Both metaproterenol sulfate and albuterol are inhaled medications commonly used to prevent exercise-induced bronchospasm. Their efficacy and duration of action in controlling exercise-induced bronchospasm were compared with placebo in 18 asthmatic children (age range: 12 to 17 years) in a single-blind randomized crossover study. Standardized treadmill exercise challenges were repeated every two hours for up to six hours following the initial exercise test. With the initial exercise challenge, both active medications blocked exercise-induced bronchospasm with equal efficacy. On the other hand, when the duration of action of the medications was compared: albuterol blocked exercise-induced bronchospasm longer than metaproterenol sulfate in eight subjects, the reverse was true in only one patient, and the medications blocked for equal duration in nine subjects. Thus, although both active agents were equally efficacious in blocking exercise-induced bronchospasm initially, the duration of action of albuterol was significantly (P less than .05) longer on serial testing than that of metaproterenol sulfate. Both medications were significantly better than placebo in efficacy and duration of action.

Adolescent↗