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Biomedical subjects

C Li

Publications and source records attributed to C Li.

At least 973 records · Page 54Linked to original sources
PubMed1995

[Lumbar spinal stenosis syndrome: classification, pathology and operative consideration].

A total of 168 cases of lumbar spinal stenosis syndrome were operated on in recent 6 years. They included 13 cases of developmental spinal stenosis and 155 cases of acquired spinal stenosis. All patients were followed up for an average of 2 years and 7 months, ranging from 3 months to 5 years and 10 months. The results of treatment were not satisfactory in developmental spinal stenosis (excellent 46.2%, good 30.7%, fair 15.4%, poor 7.7%), but good in acquired spinal stenosis (excellent 72.2%, good 22.6%, fair 5.2%, poor 0). Moreover, with different classification and pathology, acquired spinal stenosis had different results. The authors stressed that it is very important to consider the methods and the range of operation according to the pathological characteristics of myelography and CTM of lumbar spinal stenosis.

Adult↗
PubMed1995

[Influence of heating degrees on appearance of calcined shell drugs].

The colors, crisp extents and comminution rates of 4 kinds of shell drugs calcined under various conditions were conpared systematically. The appearance alterations of the calcined drugs were closely related to the heating degrees during calcining operation, and the effect of calcining duration was greater than that of calcining temperature.

Animals↗
PubMed1995

[Influence of heating degrees on internal quality of calcined shell drugs].

The internal quality of 4 kinds of shell drugs calcined under different conditions was investigated and compared in terms of the yielding ratios and total calcium content of the calcined product, Ca2+ content of the decoction and total water-soluble extractive rate. It was found that at calcining temperatures higher than 800 degrees C the internal quality of the shell drugs would change markedly.

Animals↗
PubMed1995

[Antitumor effect in vitro and immuno-response in vivo of fructus Mume].

The antitumor action of extracts from Fructus Mume and the main triterpenoid component ursolic acid on HIMeg and HL-60 cells in vitro was tested. The immuno-response in rats was also studied. The result showed that Fructus Mume had inhibiting effect on proliferation of HIMeg and HL-60 cells.

Animals↗
PubMed1995

[Amplification and overexpression of c-erbB2 in human breast cancer].

Quantitative DNA dot blot hybridization and immunohistochemical method were employed to detect amplification and overexpression of proto-oncogene c-erbB2 in 101 paraffin-embedded breast cancers. The results showed that c-erbB2 was amplified and overexpressed in 34.7% and 23.8% of examined cases respectively. The overexpression of c-erbB2 was correlated with, but not always paralled to the gene amplification. The moderate to high-level overexpression of c-erbB2 detected by immunohistochemistry was significantly associated with the size of the tumour and the number of lymph nodes involved. No differences were found in the alteratio of c-erbB2 gene and its protein expression between primary and metastatic breast cancers indicating that the genotypic and phenotypic changes of c-erbB2 occured prior to and maintained in the process of metastasis of breast cancer.

Breast Neoplasms↗
PubMed1995

Differential blockade of voltage-sensitive calcium channels at the mouse neuromuscular junction by novel omega-conopeptides and omega-agatoxin-IVA.

This investigation assessed the ability of a variety of calcium channel blocking peptides to block synaptic transmission in the isolated mouse phrenic nerve-hemidiaphragm. The synthetic version of the naturally occurring N-type voltage-sensitive calcium channel (VSCC) blocker omega-conopeptide MVIIA (SNX-111) had no effect on nerve-evoked muscle contractions. The non-N-, non-L-type VSCC blocker, omega-conopeptide MVIIC (SNX-230), blocked neuromuscular transmission completely, as did the selective P-type VSCC blocker, omega-Aga-IVA. Subsequent evaluation of other synthetic omega-conopeptides and analogs disclosed a significant positive correlation between the test compounds' affinities for high-affinity SNX-230 brain binding sites and their neuromuscular blocking potencies. Quantal analysis of transmitter release showed that SNX-230 abolished evoked endplate potentials completely, but had little effect on the amplitude and frequency of spontaneous miniature endplate potentials. Perineural focal recordings of presynaptic currents showed that SNX-230 did not block the neuronal action potential. These and other findings indicated that SNX-230 prevents transmitter release at the mouse neuromuscular junction by blocking calcium channels at presynaptic nerve endings. These calcium channels correspond pharmacologically to VSCCs associated with high-affinity binding sites in rat brain and are most probably either of the P- or Q-type.

Amino Acid Sequence↗
PubMed1995

In vitro and in vivo biotransformations of the naphthalenic lignan lactone 5-lipoxygenase inhibitor, L-702,539.

It has been reported previously that the tetrahydropyranyl naphthtalenic lignan lactone L-702,539 is a potent nonredox, 5-lipoxygenase inhibitor that has the advantage that it can be dosed either as the lactone or as the corresponding nonactive hydroxy acid L-702,618 (opened lactone). Studies with hepatic microsomes from the rat, rhesus monkey, and human were undertaken in a phosphate buffer and suggested that the closure of the hydroxy acid L-702,618 to the lactone L-702,539 was an enzymatic process. The incubation of L-702,539 under oxidative conditions with these specific hepatic microsomes resulted in the formation of three significant metabolites (> 0.4 nmol/mg protein/hr) as determined by HPLC with UV detection. These metabolites were isolated from large microsomal incubations and were characterized by MS and NMR spectroscopy. Data showed that the lactone and tetrahydropyran portions of the molecule were both susceptible to hydroxylation, and the hydroxylated tetrahydropyran was further oxidized to the hydroxy acid. Analysis of plasma samples obtained from rat and rhesus monkeys following L-702,618 administration indicated that the in vivo metabolic pathway was similar to the one observed in vitro using hepatic microsomes. Studies conducted with microsomes from genetically engineered human cell lines expressing individual cytochrome P450s indicated that the isozyme responsible for the metabolism at the tetrahydropyran ring, was P4503A4. These findings were supported by studies conducted in human microsomes using an inhibitory P4503A4 antibody and troleandomycin, which is a potent P4503A inhibitor.

Animals↗
PubMed1995

[Laparoscopic treatment of endometriosis with Nd: YAG laser and microwave].

A series of 200 cases of endometriosis were treated laparoscopically by Nd: YAG laser and microwave at Peking Union Medical College Hospital. All the operations were performed under local and topical anesthesia follow-up for 10-48 months revealed good results. Of 76 cases with infertility, 46 (60.5%) conceived after treatment. Of 114 cases with ovarian endometriomas, the cysts were no longer found in 81 cases (71.1%), decreased in size in 24 cases (21.0%). Of 180 cases with pain symptoms, 105 patients (58.3%) were achieved complete relief, Partial relief in 61 cases (33.9%). It has been found that laparoscopic surgery is effective to improve fertile rate for the patients with all the stages of endometriosis. The results showed that the microwave and Nd: YAG laser can be achieved with safety and success. The microwave is safer than Nd: YAG laser and is easier to operate and less expensive.

Adult↗
PubMed1995

Phosphorylation of rabphilin-3A by Ca2+/calmodulin- and cAMP-dependent protein kinases in vitro.

Regulation of neurotransmitter release is thought to involve modulation of the release probability by protein phosphorylation. In order to identify novel targets for such regulatory processes, we have studied the phosphorylation of rabphilin-3A in vitro. Rabphilin-3A is a synaptic vesicle protein that interacts with rab3A in a GTP-dependent manner and binds Ca2+ in a phospholipid-dependent manner. Here we show that rabphilin-3A is an efficient substrate for Ca2+/calmodulin-dependent protein kinase II, which phosphorylates rat rabphilin-3A at residue 234 and 274, and for cAMP-dependent protein kinase, which phosphorylates rat rabphilin-3A at residue 234. This identifies the middle region of rabphilin-3A situated between the N-terminal rab3A-binding sequences and the C-terminal C2-domains involved in Ca2+/phospholipid binding as a regulatory domain. Thus, rabphilin-3A is a second phosphoprotein on synaptic vesicles that, similar to synapsin I, may integrate phosphorylation signals from multiple protein kinase signaling pathways in the cell.

Adaptor Proteins, Signal Transducing↗
PubMed1995

[Observation on dynamics of circulating antigen from patients with cysticercosis before and after treatment].

The dynamics of circulating antigen (CAg) level in sera form patients with cysticercosis before and after albendazole treatment were detected by using monoclonal antibody-based double antibody sandwich ELISA (McAb-ELISA). The results indicate that after the patients with cysticercosis had been treated for one, two and three treatment courses, the levels of CAg in sera decreased with the increase in the number of treatment courses, their average OD value dropped from 0.499 before treatment to 0.291, 0.073 and 0.051 after treatment, respectively, and the corresponding negative conversion rates of CAg detection were 20.0%, 57.9% and 87.5%, respectively. Sera from eight patients who had received three courses of albendazole treatment were detected for CAg and CAb before and after treatment. The results indicate that the CAb level dropped rather slowly after three courses of treatment as compared to CAg level. It is concluded that detecting circulating antigen might be used as a promising method for evaluating the drug efficacy.

Albendazole↗
PubMed1995

Clinical application of monoclonal antibody-drug conjugate to immunotargeting chemotherapy of bladder cancer.

Monoclonal antibody-drug conjugate was applied in a clinical trial for patients with bladder cancer. Monoclonal antibody HB7A from a mouse splenocyte immunized against human bladder cancer was used as a drug carrier. The anti-cancer drug adriamycin (ADR) was bound to HB7A through a dextran (DEX) bridge to form the conjugate HB7A-DEX-ADR. The in vitro cytotoxic effect of the conjugate on BIU-87 bladder cancer cells was similar to that of free ADR and the mixture of HB7A and ADR. Seven patients with bladder cancer were given HB7A-DEX-ADR intravenously. The immunoperoxidase studies of the resected specimens showed that HB7A was localized specifically in cancer, and histological studies revealed degenerative and necrotic changes of the tumor cells. Patients receiving the conjugate did not experience serious side effects. This study suggests that immunotargeting chemotherapy with HB7A-DEX-ADR is well tolerated by patients and its cytotoxicity on tumor is substantial.

Aged↗
PubMed1995

[Electron microscopic observation of wound healing process of the laryngeal mucosa in guinea pigs].

The ultrastructural changes of wound healing process following abrading of the laryngeal mucosa with a smooth file in 16 guinea pigs were observed by scanning and transmission electron microscopies. The results showed that: 1. the repair of the laryngeal mucosa epithelial defect was initiated from mobilization and migration of residual basal cells in the surrounding tissue onto the denuded epithelial surface; 2. the regenerated epithelium of migration covered small part of the denuded epithelial surface 24 hours after sustaining the injury; 3. five days later, all denuded epithelial surface was covered by the regenerated epithelium; 4. differentiation of the regenerated epithelium began 10 days after abrasion, and was completed 21 days after abrasion; 5. tonofilaments of distributed the minority, permeation, and concentration were seen in those cells of the regenerated epithelium respectively on the 1st, 5th and 10th days after abrasion. Particularness of differentiation of the regenerated epithelium was discussed.

Animals↗
PubMed1995

[Ultracytochemical localization on Na(+)-K(+)-ATPase activity in the guinea pig endolymphatic sac].

It is well-known that Na(+)-K(+)-ATPase plays an important role in active transportion of sodium (Na) and potassium (K) ions across the epithelium. This paper reports the ultrastructural localization of the K(+)-NPPase reflecting Na(+)-K(+)-ATPase activity in the guinea pig endolymphatic sac (ES) with the lead citrate one step method. The ultrathin sections viewed in the transmission electron microscope revealed that the reaction product was restricted to the cytoplasmatic side of the basolaterl plasma membranes of the ES epithelial cells. And the reactivity could be traced all the way up to the level of tight junctions close to the luminal aspect of the cells. On the other hand, the luminal plasma membrane of the epithelial cells showed no enzyme activity. Our findings suggest that the rich Na(+)-K(+)-ATPase enzyme activity is preferentially localized on the basolateral plasma of membrane of the ES epithelial cells. Possible physiological mechanism of Na(+)-K(+)-ATPase in the Na(+)-K+ ion transport of ES epithelial cells is discussed.

Animals↗
PubMed1995

Changes of plasma endothelin and atrial natriuretic peptide during the onset and after termination of paroxysmal supraventricular tachycardia.

Radioimmunoassays were used to measure the concentration changes of plasma endothelin (ET) and atrial natriuretic peptide (ANP) during the onset and after termination of paroxysmal supraventricular tachycardia (SVT). 30 cases were reviewed and comparisons with 42 normal subjects were made. There are very significant differences (P < 0.0001) in the concentration changes of both plasma ET and ANP during the onset and 30 minutes after the termination of SVT. During the onset period of SVT, the plasma ET and ANP were markedly elevated and 30 minutes after its termination they were lowered significantly, but their concentrations were still 2-fold higher than those of the control group. As the biological effects of ANP and ET are antagonistic to each other, their parallel elevation and lowering of plasma concentrations during and after the termination of SVT reveal that these 2 hormones participate in the pathophysiological process of SVT. This phenomenon is possibly one of the homeostatic regulatory functions in the organism.

Adult↗