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Biomedical subjects

H Shi

Publications and source records attributed to H Shi.

At least 217 records · Page 12Linked to original sources
PubMed1994

[Involvement of glutamate in corticofugal modulation of intralaminar nuclei from SII via motor cortex in acupuncture analgesia].

The present experiments were designed to study the effect of glutamate on cortical somatosensory area II (S II) producing descending modulation of intralaminar nuclei (ILN) via the motor cortex (MCtx) in acupuncture analgesia. The glutamate antagonist glutamate diethylester (GDEE) or saline was topically applied at MCtx in 17 cats. Single unit activities of ILN neurons were extracellularly recorded. The results were as follows: 1. The nociceptive responses of ILN neurons were attenuated by stimulating S II after topical administration of saline at MCtx. However, the inhibitory effect of stimulating S II in the same neurons was reduced after application of GDEE. There was a significant difference at 0'-1' after the stimulation between the two groups (n = 10, P < 0.05). 2. The inhibitory effect of electroacupuncture (EA) on nociceptive responses was reduced after topical application of GDEE, while marked inhibition was shown at 0'-10' after cessation of EA in the saline control group (n = 11, P < 0.05). The results, together with the finding that the majority of S II neurons could be activated by EA, showed that glutamate released from S II to MCtx might be involved in corticofugal modulation of ILN from S II via MCtx in acupuncture analgesia.

Acupuncture Analgesia↗
PubMed1994

[Comparative study on three serologic tests for detecting antibodies in cases with bancroftian microfilaremia].

A comparative study was conducted for detecting antibody levels of bancroftian microfilaremia cases by using three serologic tests, IFAT, ELISA and dot-ELISA. A total of 102 serum specimens were collected from bancroftian microfilaremia cases. The positive rate was 89.2% (91/102) with IFAT (serum dilution > or = 1:20), 84.3% (86/102) with ELISA (OD value > or = 0.440) and 89.2% (91/102) with dot-ELISA (serum dilution > or = 1:80), respectively (P > 0.05); while in healthy individuals from non-endemic areas the false positive rate was 0(0/30), 1.8(1/55) and 0(0/54), respectively. The results indicated that there were no statistically significant differences among the three serologic tests. There was no correlation found in this study between microfilaria density and the antibody level. It was also proved that the detection rate of the combined use of either 2 or 3 tests was higher than each of the three tests; the positive rates being 94.1%-98.0%.

Animals↗
PubMed1993

Antioxidant properties of fractions and polyphenol constituents from green, oolong and black teas.

Green, oolong and black teas were extracted with water, and then the water extracts were extracted separately with three types of solvent, chloroform, ethyl acetate and butanol, to obtain eight fractions. Major flavanol was extracted by EtOAc, while most of the alkaloid was in the chloroform fraction. Thearubigin was greatest in the butanol fraction, and most of the amino acid remained in the water fraction. All fractions were systematically analyzed by UV spectrophotometer and reverse phase HPLC for those important components existing in green tea, oolong tea, and black tea. The pure compounds of (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC), (-)-epigallocatechin gallate (EGCG), free theaflavin, theaflavin monogallate-A, theaflavin monogallate-B, and theaflavin digallate were separated by LH-20 chromatography and reverse phase HPLC. All fractions and pure compounds were assayed for antioxidant activity and lipoxygenase inhibition activity. Flavanol showed very strong antioxidant activity and lipoxygenase inhibition.

Antioxidants↗
PubMed1993

[Influence of lesion of motor cortex on second somatosensory area emanating descending modulation on thalamic intralaminar nuclei].

The present study was undertaken to verify further the participation of motor cortex (MCtx) in the somatosensory area II(SII) emanating descending modulation of thalamic intralaminar nuclei (ILN). Neuronal responses in ILN to noxious stimulation of the superficial peroneal nerve were extracellularly recorded in 34 cats. The effects of electrical stimulating SII on nociceptive responses of neurons in ILN before and after lesion of MCtx were observed and compared. It was shown that electrical stimulation of SII obviously inhibited the nociceptive responses in the majority of neurons recorded (11/13) in ILN in the cats with MCtx intact (P < 0.05). After lesion of MCtx the inhibitory effect still remained (n = 10, P < 0.05), but weakened to a certain extent compared with that before lesion. In the animals with the lesion involving MCtx and the underlying subcortical structures electrical stimulating SII facilitated the nociceptive responses of ILN neurons (n = 7, P < 0.05). The results further support the idea that SII emanating descending modulation on ILN is in part fulfilled via MCtx.

Animals↗
PubMed1993

Regional distribution of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and protein mass in the ocular lens.

We have attempted to map the regional distribution of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) enzyme activity and protein mass along the radial axis of the ocular lens. Because lens plasma membrane is extremely rich in cholesterol and the lens must synthesize this cholesterol, the activity of HMGR could be a key factor controlling lens membrane formation. Lenses of young rats were divided into discrete fractions by gradual dissolution in a tergitol-containing buffer; each fraction was then equated to a specific arc of the radius based upon its protein content. Aliquots of each fraction were assayed for HMGR enzyme activity and protein mass. Relative protein mass was quantitatively estimated by Western blotting using a monoclonal antibody to HMGR with immunoreactivity detected by enhanced chemiluminescence. Lens HMGR possessed a molecular mass of about 97 kDa and localized in the cell's insoluble fraction. Peak levels of both HMGR enzyme activity and protein mass were found in the outer 5% of the lens radius; levels of both decreased precipitously from there to the outer 10% radius mark. This distribution paralleled synthesis of the membrane's cholesterol, phospholipid, and intrinsic protein. We conclude that the abrupt cessation of plasma membrane synthesis in the ocular lens could involve loss of HMGR activity over a narrow arc of the lens radius, and that this activity loss is due to disappearance of enzyme protein.

Animals↗
PubMed1993

The risk of osteoarthritis with running and aging: a 5-year longitudinal study.

Our purpose was to determine the 5-year longitudinal effects of running and aging on the development of radiographic and clinical osteoarthritis (OA) of the knees, hands and lumbar spine. Thirty-five running subjects and 38 controls, with a mean age of 63 years, were matched for age (+/- 2 years), years of education, and occupation; 33 matched pairs were constructed. All subjects underwent rheumatologic examination, completed questionnaires, and had radiographs taken of the hands, lateral lumbar spine, and knees in 1984 and in 1989. Five year radiographic results for both the runner and control groups showed OA progression for the knees, hands, and lumbar spine. In 1989, 10 (13%) of the 73 subjects fit American College of Rheumatology (ACR) criteria for clinical OA of the hand, and 9 subjects (12%) fit ACR criteria for OA of the knee. In summary, running did not accelerate the development of radiographic or clinical OA of the knees, but with aging, 13% of all subjects developed OA of the hands and 12% of all subjects developed OA of the knees.

Aged↗
PubMed1992

Molecular mimicry of hepatitis B surface antigen by an anti-idiotype-derived synthetic peptide.

Monoclonal antibody 2F10 is an "internal-image" anti-idiotype (anti-id) antibody capable of mimicking the group-specific "a" determinant of human hepatitis B surface antigen (HBsAg). By mRNA sequencing and computer-assisted molecular modeling of monoclonal antibody 2F10, we identified a 15-amino acid region of the heavy-chain hypervariable region that has partial residue homology with sequences of the "a" determinant epitopes of HBsAg. We have established that a linear 15-mer peptide from a contiguous region on the anti-id antibody can (i) generate anti-HBsAg-specific antibodies when injected into mice, (ii) prime murine lymph node cells for in vitro HBsAg-specific T-cell proliferative responses, and (iii) stimulate in vitro human CD4+ T cells that were primed in vivo to HBsAg by natural infection with hepatitis B virus or vaccination with a commercially available HBsAg vaccine. Significantly, this peptide could also stimulate CD4+ T cells of human hepatitis B virus carriers. We conclude that a 15-mer peptide derived from the anti-id sequence can duplicate the B- and T-cell stimulatory activity of the intact anti-id antibody and the antigen that is mimicked, HBsAg.

Amino Acid Sequence↗
PubMed1992

The effect of platelet activating factor on different phases of murine in vitro fertilization.

PURPOSE: Our purpose was to examine the effect of platelet activating factor (PAF) in different phases of mouse in vitro fertilization and optimal parameters that would enhance the fertilization rate. DESIGN AND SETTINGS: Various PAF concentrations (10(-7) to 10(-5) M) were selected to investigate its effect on three phases of mouse in vitro fertilization (i.e., sperm capacitation, sperm/oocyte coincubation, and preimplantation embryo growth) in three experimental groups: (I) with PAF treatment in the first phase, (II) with PAF treatment adopted in the first and second phases, and (III) with PAF treatment implemented in all three phases. RESULTS: The improvement of the fertilization rate in PAF treatment groups over the control group ranges from 6.5 to 19.0% (P < 0.05-P < 0.001). The highest enhancement of fertilization rate was achieved under the condition of PAF treatment (10(-6) M) through sperm capacitation and sperm/oocyte coincubation phases. CONCLUSION: The PAF concentration of 10(-6) M in sperm capacitation and sperm/oocyte coincubation yielded the greatest improvement in fertilization. However, continuing PAF treatment after sperm/oocyte coincubation had no beneficial effect on fertilization and preimplantation development.

Animals↗
PubMed1992

Antioxidative effect of polyphenol extract prepared from various Chinese teas.

METHODS. Twelve different types of Chinese teas, including green, semifermented, and black tea, were studied for their antioxidant activities and active components. Compositions of (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate, (-)-epigallocatechin gallate, and gallic acid were identified by fast atom bombardment-mass spectrometry and high-performance liquid chromatography-mass spectrometry and quantified by high-performance liquid chromatography. Antioxidant activities in lard were measured by the Rancimat method. RESULTS. The results showed that both yields of polyphenol extract and antioxidant activities varied with different tea processing methods. It was found that (-)-epigallocatechin gallate, (-)-epigallocatechin, and (-)-epicatechin gallate inhibited soybean lipoxygenase at the IC50 values ranging from 10 to 20 microM.

Animals↗
PubMed1992

[Involvement of acetylcholine in corticofugal modulation of pain].

We have found that after intraperitoneal injecting atropine the analgesic effect of both stimulating Sm I cortex and acupuncture were decreased. It suggests that acetylcholine (ACh) may be involved in the corticofugal modulation of pain. In order to elucidate this idea the effects of stimulating Sm I cortex on tail flick latency (TFL) after ventrical microinjecting atropine were investigated. The experiments were carried out on Wistar rats. Under the state of anaesthesia a pair of silver ball electrodes were put on the dura for electrical stimulating Sm I and the ipsilateral ventricle was cannulated for microinjecting atropine. Recordings were made 5-6 hours or 24 hours after operation. Immediately after cessation of stimulating SmI and 1', 2', 3.5', 5', 7.5', 10' and 15' later TFL were measured consecutively. The results were as follows: 1. The mean value of TFL was 2.44 +/- 0.11 sec (n = 20). It was prolonged (p < 0.05) within 0'-5' after stimulation of SmI. Therefore, it indicated that analgesic effects were produced by stimulating SmI cortex. 2. It was found that under the background of microinjecting atropine (10 micrograms/2 microliters) TFL remained unchanged after stimulating SmI cortex (n = 10, P > 0.05). There was a significant difference between the two treatments: simple stimulating SmI and atropine plus stimulating SmI at the same animals in TFL (P < 0.05) within 0' and 1' after cessation of stimulating SmI. It indicated that the analgesic effects of stimulating SmI cortex were decreased by blocking M-receptors. 3. Under the background of microinjecting normal saline.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1991

Characterization of a 54-nucleotide gap region in the 28S rRNA gene of Schistosoma mansoni.

We have analyzed 572 bp in the 28S rDNA of the human blood fluke Schistosoma mansoni which correspond to expansion segment 5 of domain IV as defined by Clark et al. for the Xenopus laevis 28S rRNA. S1 nuclease mapping and primer extension analysis comparing this region with the mature 28S rRNA indicate that there are 54 nucleotides present in the 28S rDNA which are absent from the mature rRNA. This defines a gap that creates two 28S rRNA subunits (28S alpha and 28S beta). Comparison of the S. mansoni sequence with rDNAs of other organisms which contain gaps in their 28S rRNA shows that the overall features are conserved except that the S. mansoni gap is less A + T-rich. The conserved features include: (1) the location of the gap within the 28S rRNA; (2) the predicted secondary structure of the gap, containing a stem-loop with a UAAU sequence within the loop; and (3) a conserved CGAAAGGG on the 3' side of the gap.

Animals↗
PubMed1991

[Effect of acupuncture on neuronal loss induced by axotomy in the rat hypoglossal nuclei].

It was reported previously that acupuncture promotes regeneration of rat's peripheral nerve. In order to study the effect of acupuncture on recovery of motoneuronal lesion and regeneration of central nervous system, we studied the effect of acupuncture on neuronal loss induced by axotomy in the rat hypoglossal nuclei. A total of 6 pairs of rats (acupunctured and controls in pairs) were used, (each pair of) the rats were paired of the same litter and sex. After the right hypoglossal nerves were severed, rats were reared for 14 days. In this period, we gave acupuncture therapy to the acupunctured rats but nothing to the controls. After perfusion, serial paraffin sections of brain stems of rats were cut and stained with cresyl violet. Serial sections per rat were used for counting the perikaryon of the hypoglossal nuclei. The reduced percentage of neuronal population followed axotomy was calculated. It was found that neuronal loss was less severe in acupunctured rats. Difference in the reduced percentage of neuronal population between acupunctured rats and controls was significant statistically. It was shown that acupuncture increased survival of lesioned neurons, and thus acupuncture may be helpful to the recovery of neuronal lesion. The detailed mechanism is going to be explored.

Animals↗