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Biomedical subjects

C S Li

Publications and source records attributed to C S Li.

At least 19 recordsLinked to original sources
PubMed1992

Low calcium/high magnesium medium increases activities of hypothalamic arcuate and suprachiasmatic neurons in brain tissue slices.

Extracellular single-unit recording was conducted in hypothalamic arcuate (ARC) and suprachiasmatic nucleus (SCN) in rat brain slices. The perifusion medium was switched from normal artificial cerebrospinal fluid (ACSF) to ACSF containing low Ca2+ and high Mg2+ to test the effect of extracellular calcium on the spontaneous activities of these neurons and their responses to some test agents. It was found that almost all of the ARC and SCN units tested increased their firing rates in low Ca2+, high Mg2+ ACSF, and exhibited more significant responses to excitatory test agents. The effects of low Ca2+, high Mg2+ ACSF were repeatable and reversible. The results suggest that extracellular Ca2+ is essential in maintaining the membrane stability of most hypothalamic neurons and most agents tested are acting postsynaptically on the unit recorded.

Action Potentials↗
PubMed1992

Oestrogen infusions into the amygdala potentiate excitatory transmission from the accessory olfactory bulb to tuberoinfundibular arcuate neurones in the mouse.

We have previously shown that oestrogen increases the percentage of tuberoinfundibular (TI) arcuate neurones that respond to electrical stimulation of the accessory olfactory bulb (AOB). This study focuses on the amygdala as a possible site for the hormonal modulation of AOB input to TI arcuate neurones. Local infusions of 17 beta-oestradiol (30 pmol) into the amygdala of ovariectomized female mice significantly potentiated excitatory responses of TI arcuate neurones to AOB stimulation. This effect appeared rapidly (less than 10 min) after infusion. The inactive oestrogen isomer, 17 alpha-oestradiol, infused in the same manner, was without effect. These results suggest that oestrogen acts directly on amygdala neurones, thereby modulating olfactory information relayed along the vomeronasal pathway to TI arcuate neurones.

Amygdala↗
PubMed1992

Cholecystokinin: critical role in mediating olfactory influences on reproduction.

Our electrophysiological studies in female mice have demonstrated that electrical stimulation of the accessory olfactory bulb excites tuberoinfundibular dopaminergic arcuate neurons via the amygdala-stria terminalis route. This study shows that the medial preoptic area is identified as an additional relay for the excitatory transmission by examining the effectiveness of locally infused lignocaine anaesthetic in blocking the transmission and that of electrical stimulation in evoking a shorter latency response. Based on the known immunohistochemical findings, further attention is focused on a transmitter mediating synaptic transmission in the medial preoptic area. The cholecystokinin-B type receptor antagonist L-365,260 (0.3, 0.6, 0.9 pmol), but not the A type receptor antagonist L-364,718 (0.9 pmol), infused into the medial preoptic area, blocked the excitation of tuberoinfundibular arcuate neurons in a dose-dependent manner. Conversely, cholecystokinin octapeptide (0.6 pmol) increased firing activity in such neurons. The antagonizing effect of L-365,260 was reproduced in the context of the olfactory block to pregnancy: bilateral infusions of this drug into the medical preoptic area of recently mated females immediately before exposures to strange males' pheromones prevented them from inducing pregnancy block. These findings implicate cholecystokinin acting on cholecystokinin-B receptors in the medial preoptic area as a mediator of olfactory influences on reproductive physiology.

Animals↗
PubMed1992

Antilactoferrin antibody in systemic lupus erythematosus.

Lactoferrin is a secondary granule protein of neutrophils. Seventy-nine systemic lupus erythematosus patients who fulfilled the ARA criteria for classification were tested for antibody against human lactoferrin (LF-ab) by ELISA. Thirty-one of these (39.2%) demonstrated elevated levels. There was significant correlation between LF-ab positivity and disease duration. Clinical flare was common with positive LF-ab (P less than 0.05). Disease manifestations were independent of antibody status except for an increased incidence of lymphadenopathy and crescentic gomerulonephritis among those who had LF-ab. No consistent immunofluorescence pattern could be demonstrated on alcohol-fixed neutrophils for the LF-ab positive sera. It is suggested that LF-ab is related to lupus activity, and can be useful as a marker for disease monitoring.

Adolescent↗
PubMed1992

[Clinical and experimental studies of royal made ping an dan on treatment of motion sickness].

This paper presents the results of clinical observation and experimental research of Royal Made Ping An Dan (RPAD) of the Imperial Hospital of Qing Dynasty. The clinical results showed that RPAD was effective in treating 343 patients with motion sickness, and their average time for producing effect was 24.1 +/- 13.5 minutes. The total effective rates of dramamine group and Ren Dan group were 69.4% and 67.7% respectively, the latter included 45.7% of basically cured and 55.0% of markedly effective cases. There were significant differences among these groups (P < 0.05-0.01). It revealed that the effect of RPAD was better than that of dramamine and Ren Dan. According to laboratory findings, RPAD had the ability of alleviating symptoms of motion sickness and inhibiting eyeball tremor and improving meningeal microcirculation of experimental animals.

Animals↗
PubMed1992

Experimental research on antimotion sickness effects of Chinese medicine "pingandan" pills in cats.

Pingandan was a secret prescription for treatment of stomach upset, nausea and vomiting for emperors in the Qing Dynasty of China. This study was to compare the effects of Pingandan with those of scopolamine and dramamine on motion sickness (MS) and nystagmus. Fourteen cats were tested in a parallel swing (0.22 Hz, 3.9 m/S2) for 20 min, and then in a rotating chair (10 degrees/S2, 20 rpm) for 1-2 min. The effects of scopolamine 1 mg, dramamine 25 mg and three doses of Pingandan 50x, 30x, 10x of 0.45 g/kg were observed and compared to placebos. These drugs or placebos were administered to each cat 30-60 min prior to the tests. The post-rotary nystagmus and MS symptoms were recorded. The Suri's scale for MS severity, Latin square and double blind techniques were used. The interval between any two tests was 2-5 days. It was found that Pingandan 50x and scopolamine 1 mg were more effective than placebos in reducing MS symptoms (P less than 0.01) and suppressing slow phase velocity of nystagmus (P less than 0.05), while Pingandan 30x significantly reduced MS symptoms only (P less than 0.01). Pingandan 10x and dramamine 25 mg had no anti-MS effect. Chinese medicine Pingandan is an effective anti-MS drug.

Animals↗
PubMed1991

Intracranial lipoma in the medulla oblongata.

Intracranial lipoma in the medulla oblongata has been rarely reported. Only two cases have been documented in the literature. This report concerns a patient who complained of nuchal soreness and an unstable gait for 6 months. An olivelike lipoma, arising from the posterior aspect of the medulla oblongata and embedded in the lower cranial nerves, was found at suboccipital craniectomy and posterior laminectomy of C1-2. Partial removal of the lipoma was performed for decompression; radical removal would have been hazardous. The clinical symptoms subsided postoperatively. The computed tomography scan and magnetic resonance image proved useful for properative diagnosis.

Aged↗
PubMed1991

Efficacy of air cleaning systems in controlling indoor radon decay products.

Field evaluations of an air filtration system and an electronic air cleaner to remove Rn decay products were performed in a single-family house located in the Northford, CT area. Field measurements included the Rn concentration, particle number concentration, and concentration and activity size distribution of Rn decay products. A semi-continuous screen diffusion battery system with six parallel sampler/detector units was used to determine the concentrations and size distributions of the Rn decay products. Indoor particles were generated by common activities such as vacuuming, washing and drying clothes, opening the outside door, and cooking. Influences on the size distributions over the size range from 0.5 nm to 500 nm of Rn decay products were investigated in the domestic environment. The effect of the air cleaners was to decrease the concentration of the decay products and to reduce the equilibrium fraction. For the filtration system in particular, the activity fractions in the smallest size range were increased. However, the overall effect of the air cleaners was to reduce the median dose. The filtration unit was found to be more effective than the electronic air cleaner.

Air Pollution, Indoor↗
PubMed1991

Experiences in the management of cerebellopontine angle tumour: an analysis of 64 cases.

The surgical aspects of 64 consecutive cases of cerebellopontine angle tumours treated from January 1983 to December 1988 are reviewed. Nearly all of the procedures were done through a small suboccipital craniectomy. Two patients underwent a combined subtemporal- suboccipital approach. A stage-operation was performed on three patients harbouring a large to giant-size acoustic neuroma. The most common sign was loss of corneal reflex (29%). Hearing loss was present in 33 patients (51%). Trigeminal neuralgia occurred in 13 patients (20%) on the affected side. Hemifacial spasm was present in one patient with a 2-cm meningioma. The tumour pathology comprised of 37 acoustic neuromas, 16 meningiomas, 5 epidermoid cysts, 3 trigeminal neuromas, 1 metastatic adenocarcinoma, 1 facial neuroma, and 1 tuberculoma. Anatomic continuity of the facial nerve was preserved in 40 patients (66%). Operative mortality rate in this series was three (4.7%). None of the patients has had other further significant neurological deficits postoperatively. Most of our patients were in good condition after the operative procedures.

Adolescent↗
PubMed1990

GABAergic mechanisms are involved in the control of tuberoinfundibular arcuate neurons by the accessory olfactory bulb.

In this study we examined electrophysiologically the involvement of the intrinsic GABAergic system of the accessory olfactory bulb (AOB) in controlling the activity of tuberoinfundibular (TI) arcuate neurons in anaesthetized female mice. Local infusions of the gamma-aminobutyric acid-A (GABAA) receptor antagonist, bicuculline into the AOB enhanced the spontaneous firing activity of TI arcuate neurons with excitatory inputs from the AOB. This finding reveals a neural mechanism responsible for the pregnancy blocking effect of this drug in freely behaving female mice and, taken together with the cytoarchitecture of the AOB, suggests that the reciprocal dendrodendritic interaction between mitral cells and GABAergic granule cells in the AOB is critical to control of AOB output to TI arcuate neurons as part of the final common pathway of the accessory olfactory system.

Animals↗
PubMed1990

Neural mechanisms underlying the action of primer pheromones in mice.

Our electrophysiological experiments in female mice have provided evidence that electrical stimulation of the accessory olfactory bulb orthodromically excites a subpopulation of tuberoinfundibular arcuate neurons by way of the amygdala. The present study shows that half of such neurons are identified as dopaminergic by examining the effectiveness of infusing 6-hydroxydopamine and 5,7-dihydroxytryptamine locally into the median eminence in blocking their antidromic response. Further attention is focused on excitatory amino acid receptors within the amygdala and the amygdaloid pathway that mediate the accessory bulb-induced excitation of tuberoinfundibular arcuate neurons. The excitatory transmission was reversibly blocked by intra-amygdala infusion (3 nmol) of the excitatory amino acid antagonists kynurenic acid, D,L-2-amino-5-phosphonovalerate, gamma-D-glutamylaminomethylsulphonate and D,L-2-amino-4-phosphonobutyrate. Intra-amygdala infusions (3 nmol) of N-methyl-D-aspartate and kainate markedly enhanced the firing activity of tuberoinfundibular arcuate neurons with excitatory inputs from the accessory bulb, whereas similar infusions of quisqualate were without effect Intra-stria terminalis infusions of the local anaesthetic lignocaine completely abolished the excitatory transmission in all the cells tested. Furthermore, tuberoinfundibular arcuate neurons stimulated from the accessory bulb were also orthodromically stimulated from the stria terminalis with a shorter latency. These studies demonstrate that the projections of the accessory olfactory bulb activate excitatory amino acid receptors within the amygdala and subsequently the stria terminalis route, thereby causing excitation of tuberoinfundibular dopaminergic arcuate neurons. This functional pathway can account for the reproductive effects so far described as a consequence of vomeronasal chemoreception.

Amino Acids↗
PubMed1990

Influence of dorsal hippocampal stimulation and dorsal fornix lesions on hepatic glucose metabolism in rabbits.

We examined the effects of stimulation of the dorsal hippocampus and lesions of the dorsal fornix on glucose metabolism in liver slices of rabbits. Hippocampal stimulation decreased the 14C transfer rates from 14C-glucose into CO2, ketone bodies, cholesterol ester and free fatty acids, but increased the rates into triglyceride, phospholipids and glycogen. Fornix lesions had various effects on glucose metabolism, and the effects of hippocampal stimulation on glucose metabolism were abolished by fornix lesions. These observations support the hypothesis that the hippocampus is an integral part of the brain regulator system in the hepatic glucose metabolism.

Animals↗
PubMed1990

[Isolation and identification of yibeinoside A].

Two steroidal alkaloids were isolated from the bulb of Fritillaria pallidiflora Schreb by column chromatographic techniques. One of them was identified as known alkaloid sinpeinine A, another alkaloid was found to be a new compound named yibeinoside A, which is the Sinpeinine-3-O-beta-glucoside. Its structure was confirmed on the basis of chemical and spectral data (IR, MS, 1HNMR, 13CNMR).

Cevanes↗
PubMed1990

Newcastle bone disease in Hong Kong: a study of aluminum associated osteomalacia.

We measured serum aluminum concentrations in 104 haemodialysis patients from 3 centres in Hong Kong. We found that the 52 patients dialyzed in unit A had much higher mean aluminium levels (100 micrograms/L) than those from the other two units (61 and 39 micrograms/L respectively). In unit A, where water treatment by reverse osmosis had been introduced only recently, 30.8% of patients had fractures/looser zones, 46.2% had rugger-jersey spine and 28.8% had skeletal erosions. When these patients were divided into two groups according to whether their serum aluminium concentration was below or above 100 micrograms/l, the latter patients had significantly lower alkaline phosphatase, serum phosphate, and higher total prescribed dose of aluminium hydroxide. It was concluded that both dialysate aluminium and oral aluminium intake seemed to have contributed to the high incidence of osteomalacic fractures among Unit A patients. In eight of these patients serum aluminium increased by more than 150 micrograms/L after four weeks of receiving 1.5 g desferrioxamine twice weekly. Serial X-rays showed that the mean time after dialysis for the appearance of fractures/Looser zones was 72 months. Three patients developed fractures/Looser zones after successful renal transplantation; and it was postulated that the prompt excretion of aluminium permitted increased osteoclastic activity, resulting in fractures in these patients.

Adult↗
PubMed1990

[Hyperlipidemia treated with xiaobu jianfei pian].

A total of 51 cases with hyperlipidemia, who were defined deficiency symptom-complex complicated by symptoms of excessiveness in TCM were studied clinically. The patients were divided into two groups at random. One group was treated with Xiaobu Jianfei Pian (XJP) as treated group, another with Fangfeng Tongsheng San as a control. It was found that XJP was able to lower total serum cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and apolipoprotein (apo) B significantly (P less than 0.001, 0.001, 0.001) while it had markedly improved clinical symptoms. It was also observed that XJP had good effects on the ratios of apoA1/B and TC/HDL-C, and was able to reduce body weight index. All of these were better than those of the control group statistically. These evidences indicate that XJP possesses clinical therapeutic effects on both lipid-lowering and lipid-adjusting, which suggest that XJP may be an effective anti-hyperlipidemia medicine.

Adult↗
PubMed1989

Excitatory influence of the accessory olfactory bulb on tuberoinfundibular arcuate neurons of female mice and its modulation by oestrogen.

The role of the accessory olfactory bulb in conveying pheromonal information to tuberoinfundibular arcuate neurons was examined electrophysiologically in chloral hydrate-anaesthetized, oestrogen (0.5 micrograms in silastic capsules)-treated and untreated ovariectomized Balb/c female mice. Electrical stimulation of the accessory olfactory bulb orthodromically excited part of tuberoinfundibular neurons which were antidromically stimulated from the median eminence and histologically verified as being located within the arcuate nucleus. No inhibitions followed accessory bulb stimulation. The excitatory response to accessory bulb stimulation was reversibly blocked by the local anaesthetic lignocaine infused into the amygdala. The percentage of tuberoinfundibular arcuate neurons responding to accessory bulb stimulation was significantly higher in oestrogen-treated than in untreated animals. There was no difference between the two groups for the antidromic activation threshold, spontaneous firing rate, absolute refractory period or frequency of successful antidromic propagation into the soma of tuberoinfundibular arcuate neurons. In oestrogen-treated preparations, tuberoinfundibular arcuate neurons responsive and unresponsive to accessory bulb stimulation could be distinguished by the frequency of successful antidromic propagation into the soma. These studies demonstrate that olfactory relay neurons in the accessory olfactory bulb act to enhance the activity of a subpopulation of tuberoinfundibular arcuate neurons via the amygdala and that this neural transmission is modulated by oestrogen.

Action Potentials↗
PubMed1989

[Pharmacodynamics of dihydroartemisinine against Plasmodium berghei in mice].

Dihydroartemisinine (DHA) is a derivative of qinghaosu(artemisine), which is an antimalarial drug. DHA was given to mice inoculated with Plasmodium berhgei ANKA strain by intramuscular injection. Within proper dose range, the dose-effect and time-effect curves of DHA against the malaria can be described by y = 4.9960 + 2.9536 x and y = 7.2654 - 0.3414 t, respectively, where y is the estimated value of parasitemia suppressing rate in probit; x is log dose; t is the period since drug administration im. Accordingly, the ED50 = 1.00 +/- 0.13 mg/kg and the time of half-effect was 6.6 h, when the dose was 5.0 mg/kg im. The elimination rate constant of the effective dose in vivo was 0.2662h-1 with a half-life of 2.6 h.

Animals↗