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Biomedical subjects

K Y Li

Publications and source records attributed to K Y Li.

At least 19 recordsLinked to original sources
PubMed2000

Study on facial motoneuronal death after proximal or distal facial nerve transection.

BACKGROUND: Among the cranial nerves, the facial nerve is most liable to be damaged. Pathologic changes in the facial motor nucleus (FMN) after nerve injury are not well recognized, and the optimal time for facial nerve reconstruction after axotomy is controversial. In this study, to clarify the pathologic change in the FMN after axotomy and to determine the best time for surgery, facial motoneuronal death was investigated after facial nerve injury. METHODS: Sixty Wistar rats were divided into proximal and distal groups. In the proximal group, the right facial nerve was transected at the porus of internal acoustic meatus. In the distal group, the nerve was cut at the stylomastoid foramen. The animals were sacrificed from day 3 to day 60 after surgery, and the brainstem was fixed with 4% paraformaldehyde. The FMN were then examined in serial sections stained with Cresyl Violet, and facial motoneurons were counted under a light microscope. RESULTS: The death rate of facial motoneurons in the animals that underwent proximal axotomy was found to be higher and cell death occurred earlier than in the distal axotomy animals at every time point. Moreover, neuron death increased with time and peaked at 15 days after surgery. CONCLUSIONS: The results indicate that the injury site was correlated with facial motoneuronal death, and suggest that reconstructive surgery should be performed as early as possible.

Animals↗
PubMed2000

[Distribution of cholinergic efferent vestibular neurons].

OBJECTIVE: To investigate the effect and distribution of cholinergic efferent vestibular neurons in normal wistar rat. METHOD: HPR retrograde tracer and Immunocytochemical techniques were used. RESULT: Results show that AchT immunoreactive neurons locate in dorsolateral and dorsomedial to genu of the facial. Few neurons scatter in the parvocellular nucleus. CONCLUSION: As a neural transmitter, acetylcholine distribute in efferent vestibular neurons and play an important role.

Animals↗
PubMed1997

A patient with Graves' disease, thrombocytopenia and chronic hepatitis B.

A 22-year-old Chinese man, a HBsAg carrier, presented with relapse of thyrotoxic Graves' disease complicated by thrombocytopenia and hepatitis. Platelet count and liver enzymes gradually improved following successful treatment of the thyrotoxicosis with radioactive iodine. Possible pathogenetic links and therapeutic implications are discussed.

Adult↗
PubMed1997

Relationship between electroacupuncture analgesia and dopamine receptors in nucleus accumbens.

AIM: To study the roles of dopamine (DA) D1 and D2 receptors in nucleus accumbens in electroacupuncture analgesia (EAA) and the potentiation of EAA of rats induced by l-tetrahydropalmatine (l-THP), a dopamine receptor antagonist. METHODS: SK&F-38393 and quinpirole hydrochloride (Qui), highly selective agonists of D1 and D2 receptors, respectively were injected into nucleus accumbens of rats. RESULTS: SK&F-38393 (5 and 10 micrograms) attenuated the potentiation of EAA induced by l-THP, 10 micrograms SKF38393 attenuated EAA as well, while Qui (10 and 20 micrograms) had no effect on EAA and the potentiation of EAA induced by l-THP. CONCLUSION: D1 but not D2 receptor in nucleus accumbens play an important role in EAA and the potentiation of EAA induced by l-THP.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1997

Acromegaly in a woman presenting with diabetic ketoacidosis and insulin resistance.

A 22-year-old Chinese woman presented with typical features of diabetic ketoacidosis. There was a family history of diabetes but she was not obese. Plasma glucose and bicarbonate levels were 27.0 mmol/l and 5 mmol/l, respectively. Significant insulin resistance was noticed: she needed up to 15 units of insulin per hour. She required up to 120 units daily for her diabetic control even after her acidosis had subsided. She was then noticed to have the clinical features of acromegaly. The diagnosis was confirmed, and a cranial CT scan confirmed the presence of a pituitary macroadenoma. She underwent uneventful trans-sphenoidal resection of the tumour and her insulin requirement gradually lessened. Acromegaly should be considered in the differential diagnosis of unexplained insulin resistance.

Acromegaly↗
PubMed1996

Thyrotoxicosis and renal tubular acidosis presenting as hypokalaemic paralysis.

A 34-yr-old Chinese woman presented with hypokalaemic periodic paralysis. She had a goitre and was biochemically thyrotoxic. However, she also had urinary potassium loss with a metabolic acidosis and reduced ability to acidify her urine. The co-existence of distal renal tubular acidosis (RTA) was confirmed. There was no evidence of xerostomia or xerophthalmia, although anti-Ro antibody and rheumatoid factor were positive. Paralytic attacks did not recur after the thyrotoxicosis was controlled with radioactive iodine. Possible pathogenic mechanisms for the association of these disorders are discussed. Female patients presenting with thyrotoxic periodic paralysis (TPP) should be thoroughly investigated for possible additional precipitating factors in view of the strong male predominance of TPP, particularly when there are atypical metabolic features.

Acidosis, Renal Tubular↗
PubMed1994

Iron enhances uptake of mineral particles and increases lipid peroxidation in tracheal epithelial cells.

The factors that determine whether an exogenous mineral particle will be taken up by tracheobronchial epithelial cells are unclear. We have previously proposed that active oxygen species play a role in this process, most likely through iron-catalyzed formation of hydroxyl radical and subsequent lipid peroxidation of cell membranes. To further examine this hypothesis, we prepared rat tracheal explant cultures and exposed them for 1 h to suspensions of amosite asbestos or titanium dioxide (rutile) that had been preincubated with varying concentrations of a mixture of ferrous and ferric chloride. Explants were then maintained in organ culture in air/CO2 for 1 wk to allow particle or fiber uptake to occur. Particles or fibers in the tracheal epithelium were determined by light microscopic morphometry. Similarly treated explants were assayed for malondialdehyde as a measure of lipid peroxidation in the epithelial cells. Asbestos fibers without added iron caused lipid peroxidation, but this was not true of titanium dioxide particles. For both types of dust, increasing adsorbed iron concentrations were associated with increasing particle uptake and increasing lipid peroxidation. These observations suggest that cationic iron may play a major role in particle uptake by tracheobronchial epithelia, and that particle uptake is also related to iron-mediated lipid peroxidation.

Adsorption↗
PubMed1993

Central expression of c-fos protein after peripheral noxious thermal stimulation in awake rats.

This study applied immunohistochemistry method to examine the pattern of c-fos expression in the neuraxis following peripheral noxious thermal stimulation accomplished by immersion of tail of awake rat into hot water (50 degrees C). In unstimulated control rats, no obvious baseline expression of c-fos protein was found except in nucleus paraventricularis hypothalami and colliculus inferior, probably associated with restraint-induced stress and auditory stimulus, respectively. Noxious thermal stimulation resulted in the activation of c-fos expression, and bilateral increased nuclear immunostaining was counted in dorsal horn of lumbar and sacral segments of spinal cord (laminae I, II), nucleus raphe dorsalis, substantia grisea centralis (ventralis), nucleus paraventricularis thalami, nucleus anterior thalami, nucleus ventralis thalami, nucleus medialis thalami, nucleus reuniens, nucleus rhomboideus, nucleus habenulae lateralis, nucleus paraventricularis hypothalami, nucleus arcuatus, nucleus lateralis hypothalami, nucleus preopticus lateralis, nucleus septi lateralis, nucleus amygdala, nucleus striae terminalis, nucleus tractus diagonalis, and cortex cerebri. The results demonstrated that peripheral noxious stimulation induced central c-fos protein expression in a pattern of labeling nociresponsive cells.

Animals↗
PubMed1992

[Changes of central glucose metabolism following caudate stimulation produced analgesia in the rat--an autoradiographic deoxyglucose A study].

Sokoloff's 2-deoxyglucose (2-DG) autoradiographic technique was used to identify changes of glucose metabolic rate in the rat brain following unilateral stimulation of the head of the caudate nucleus. The results were as follows. The local glucose metabolic rate after noxious stimulation was increased in the somatosensory cortex, cingulate cortex, ventroposterior and parafascicular nucleus of the thalamus, septal area, habenular nucleus, head of caudate nucleus, periaqueductal gray (PAG) and dorsal raphe nucleus (P < 0.05). After stimulating the head of the caudate nucleus, the local glucose metabolic rate of nucleus raphe magnus (rm) and nucleus paragigantocellularis (pgcl) was increased significantly and that of the PAG and dorsal raphe nucleus had a tendency to increase, while stimulation of the head of caudate nucleus could partially abolish the increased glucose metabolic rate in the somatosensory cortex, cingulate cortex, ventroposterior and parafascicular nucleus of the thalamus, septal area and habenular nucleus as induced by noxious stimulation. These results suggest that caudate stimulation is able to depress the activation of some brain structures related to nociception and to activate those related to antinociception. The pgcl, rm, PAG and dorsal raphe nucleus might be the key structures participating in the caudate stimulation produced analgesia.

Animals↗
PubMed1992

Neuroprotective effects of phencyclidine on acute cerebral ischemia and reperfusion injury of rabbits.

Acute cerebral ischemia and reperfusion injury of rabbits was produced by permanently occluding the vertebral arteries and temporarily clamping the common carotid arteries for 30 min. Phencyclidine [1-(phenylcyclohexyl)piperidine, PCP] 40-80 micrograms.kg-1 icv 30 min before ischemia significantly attenuated the decrease of the total power of electroencephalogram (EEG) within 30 min of ischemia and improved the recovery of brain electric activity following reperfusion. PCP 20-80 micrograms.kg-1 dose-dependently suppressed the creatine kinase (CK) release during cerebral ischemia and reperfusion, and PCP 40-80 micrograms.kg-1 reduced brain ischemic damage. These improvements indicated that PCP has protective effects on acute cerebral ischemia and reperfusion injury.

Animals↗
PubMed1990

The relationship between chi-square statistics from matched and unmatched analyses.

The McNemar chi-square statistic for testing the equality of proportions in matched pairs of binary data is expressed as a function of the Pearson chi-square statistic and a kappa statistic for measuring interrater agreement. Implications for data analysis and for sample size determination are discussed. The result is generalized to provide a similar relationship between Cochran's Q-statistic and the Pearson chi-square statistic for the comparison of proportions in matches of size m.

Chi-Square Distribution↗
PubMed1990

Carotid body chemoreceptor response to prolonged hypoxia in the rabbit: effects of domperidone and propranolol.

1. The discharge of single afferent chemoreceptor fibres was recorded from the cut sinus nerve over periods of 60 or 90 min of constant, isocapnic hypoxia (arterial O2 pressure, Pa,O2, 3.13-5.25 kPa), in twenty anaesthetized rabbits, after dividing the sympathetic supply to the carotid body. 2. Under control conditions, discharge after 60 min of hypoxia adapted to a mean (S.E.M.) of 71.95 (2.75)% of that attained at 5 min of hypoxia in twenty-three hypoxic experiments. This adaptation was more pronounced when Pa,O2 was lower than 4 kPa (30 Torr). 3. Domperidone (1 mg kg-1 bolus + 1 mg kg-1 h-1 infusion I.V.), increased normoxic afferent discharge by a mean of 142%. In ten experiments, discharge after 60 min of hypoxia adapted to a mean (S.E.M.) of 56.22 (+/- 3.40)% of that attained at 5 min of hypoxia which was significantly different from control hypoxic runs (P = 0.006). 4. In seven experiments propranolol (1 mg kg-1 bolus + 1 mg kg-1 h-1 infusion I.V.) did not affect the normoxic discharge. The mean adaptation of discharge after 60 min of hypoxia was to 77.43 (3.97)% of discharge attained at 5 min of hypoxia, which was not significantly different from control hypoxic runs (P = 0.34). 5. Under control conditions plasma [K+] increased steadily during 60 min of hypoxia, in fourteen experiments, from a mean of 2.76 (0.14) to 2.85 (0.12) mmol l-1 but this was not significant (P = 0.21). Domperidone (n = 6) did not affect plasma [K+] at any time, but after propranolol (n = 6) it increased by a mean (S.E.M.) of 0.39 (0.09) mmol l-1 (P = 0.01) in normoxia and by a further 0.62 (0.28) mmol l-1 (P = 0.08) at 60 min of hypoxia. 6. The results suggest that the adaptation of chemoreceptor discharge to hypoxia in the rabbit is not mediated by changes in plasma [K+]; in addition, endogenous dopamine, but not noradrenaline, contributes to the maintenance of chemoreceptor discharge in prolonged hypoxia.

Action Potentials↗
PubMed1990

Effects of destruction of preoptic catecholaminergic nerve terminal on acupuncture analgesia.

The present work studied the effect of preoptic catecholamine on acupuncture analgesia. The catecholaminergic terminals were destructed by microinjection of 6-hydroxydopamine into the preoptic area and the destruction was checked by fluorescence histochemical method. The results showed that the destruction of catecholaminergic terminals significantly enhance acupuncture analgesia, suggesting that the reduction of catecholamine content in the preoptic area may enhance acupuncture analgesia.

Acupuncture Analgesia↗
PubMed1990

[Effects of destruction of preoptic catecholaminergic nerve terminals on acupuncture analgesia].

The effect of microinjection of 6-hydroxydopamine into the preoptic area was studied to observe the effect of destruction of catecholaminergic terminals in the preoptic area on acupuncture analgesia. It was shown that the analgesic effect of acupuncture was significantly enhanced in 6-hydroxydopamine treated group on the second and fourth day after injection as compared with those before injection or those in control group. The fluorecence of catecholamine terminals in the preoptic area disappeared almost completely on the fourth day after injection, and did not restore on the tenth day. The data indicate that the reduction of catecholamine content in the preoptic area may enhance acupuncture analgesia.

Acupuncture Analgesia↗
PubMed1990

[Change of preoptic opiate receptors after injection of 6-OHDA into sublocus coeruleus in the rabbit].

The formaldehyde histofluorescence method and receptor autoradiography were respectively used to investigate the distribution and densities of the catecholamine (CA) terminals and [3H]-etorphine binding sites, after 20 days of injection of 6-hydroxydopamine (6-OHDA) into N. subcoerulens of the rabbit. The results showed that both CA terminals and [3H]-etophine binding sites in the preoptic area, especially in the medial preoptic area, were reduced in 6-OHDA pretreated animals, thus suggesting the possible location of opioid receptors on the CA terminals.

Animals↗
PubMed1990

[Effect of electroacupuncture on electroconvulsive shock--an autoradiographic study for opioid receptors].

Radioreceptor-binding assay combined with autoradiography technique in the brain slices of rats was used to investigate cerebral areas related to electroconvulsive shock (ECS) and to analyze changes of opioid receptors of these areas in electroacupuncture (EA) anticonvulsion. The results from image processing and detection of optic density (O.D.) showed that repeated ECS resulted in an increase of opioid receptor densities in the caudate nucleus, hippocampus, habenulae nucleus and amygdala. In the group of EA plus ECS, however, the opioid receptor densities in the hippocampus, habenula nucleus and amygdala decreased as compared with that in ECS group. In addition, the receptor density in the caudate nucleus showed a decrease tendency. The results provided morphological evidence of the involvement of opioid receptors in these cerebral areas in the process of ECS and EA anticonvulsion.

Animals↗