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Biomedical subjects

X Liu

Publications and source records attributed to X Liu.

At least 919 records · Page 51Linked to original sources
PubMed1999

[Molecular clone and sequence analysis of cDNA fragments of hog cholera virus strain C].

The 5' nonencoding region, p23 and p14 encoding region and E1 gene of hog cholera virus (HCV) strain C were amplified from total RNA extracted from HCV strain C infected rabbit spleen by reverse transcription and nested or half--nested PCR. The PCR products were cloned into pGEM-T vector. Nucleotide sequencing was performed using an ABI PRISM sequencing device; based on the incorporation of fluoresect labelled dideoxynuclotide teminators. The obtained sequences on 5' noncoding region and part of p23 and p14 encoding region were compared with HCV strains Shimen and C sequenced in Moormann's lab. The result showed that the homology between HCV strains C sequenced in this report and in Moormann's lab was 99.19%, and the homology between HCV strains Shimen, the standard virulent HCV strain in China, and C sequenced in this report was 94.69%. It was also discovered that the base C at 244 of the genome of HCV strains Shimen and C sequenced in this report was absent at the genome of C strain sequenced in Moormann's lab et al.

5' Untranslated Regions↗
PubMed1999

[Observation on efficacy of artemether compound against vivax malaria].

AIM: To observe the efficacy of artemether compound against vivax malaria. METHODS: Each artemether compound tablet contains 120 mg benflumetolum and 20 mg artemether. 132 patients with vivax malaria were divided into 3 groups. Group A, 36 patients received 8 tablets as an initial dose, followed by 4 tablets daily for 2 days; group B, 41 patients received 8 tablets as an initial dose, followed by 3 tablets daily for 4 days; group C, 55 patients receiving chloroguine-primaquine served as control. Two patients of group A were voluntarily to be bitten by Anopheles dirus before and after medication to observe the influence of artemether compound on the sporogony. RESULTS: The average defervescence times for groups A, B and C were 22.3 h, 23.2 h and 25.0 h (P > 0.05), respectively, the average parasite clearance times were 33.5 h, 30.5 h and 44.9 h, respectively, the average parasite clearance times of groups A and B were all significantly shorter than that of group C (P < 0.01). The replase rates of groups A, B and C were 84.9%, 78.8% and 22.9%, respectively, followed-up at nine months, the relapse rates of groups A and B were higher than that of group C(P < 0.01). CONCLUSION: Two regimens of artemether compound have the advantage of high efficacy against vivax malaria.

Adolescent↗
PubMed1999

[Surgical treatment of laryngeal carcinoma in the elderly over 70].

OBJECTIVE: To explore the possibility and perioperative management of laryngectomy in the elderly over 70. METHOD: The records of 28 patients of laryngeal carcinoma aged 70 and over treated with laryngectomy were reviewed. RESULT: Among the 28 cases, 23 cases (82.1%) had one or more concomitant diseases or laboratory abnormalities. Most of them were cardiovascular disorders (60.7%) and respiratory disorders (25%). Total laryngectomy was performed in 15 cases. Partial laryngectomy was performed in 12 cases. Vocal cardectomy was performed in 1 case. The neck dissection was performed in 3 cases. No operative accident and death had happened in this group. The rate of postoperative complications was 32.1%. CONCLUSION: The elderly over 70 can tolerate laryngeal surgery well if the case is properly selected and careful perioperative management.

Aged↗
PubMed1999

[Synthesis and distribution of type IV collagen in mice testes].

OBJECTIVE: The variations of the synthesis and distribution type IV collagen in the testes of young, adult, and old mice were studied. METHODS: Biotin-avidin DCS system indirect immunofluorescence technique and in situ hybridization method were used. RESULTS: Sertoli cell could synthesize type IV collagen. Type IV collagen was present in the basement membrane of seminiferous tubules in mouse testis. Type IV collagen mRNA signal was seen in the Sertoli cells. The content of type IV collagen and type IV collagen mRNA peaked at day 15, and then declined successively to adult value and the aged value. CONCLUSIONS: The results suggest that the extracellular matrix of testis might play an important role in the process of spermatogenesis.

Age Factors↗
PubMed1999

[Grey relational analysis on early bolting of Angelica and its main factors].

Selecting the principal environmental and cultivated factors from the main production areas of Angelica sinensis in Gansu, the problem of early bolting were analysed with grey system theory. After the quantitative analysis, the relational grade was: elevation > precipitaton > density of crop > organic fertilizer > phosphorus fertilizer > nitrogen fertilizer. The research would provide scientific basis for check on the rate of the early bolting of Angelica effectively as well as improve the product and benefits.

Altitude↗
PubMed1999

[Experimental studies on pharmacodynamic effect of Macleaya cordata].

The pharmacodynamic effect of Macleaya cordata was investigated in this study. The results showed that Macleaya cordata could improve liver function of acute hepatic injuries in rats caused by tetrachloromethan or galactoslmine. Macleaya cordata could lessen the level of serum LDH and mortality of rats, increase ratio of serum A/G, protect cellular membrane efectively and inhibit fibrosis in rats with chromic heptic injury caused by tetrachloromethane. Macleaya cordata still enhanced the function of T and B lymphocytes.

Albumins↗
PubMed1999

[Experimental studies of Chinese taihe chicken on effects of "Qi" reinforcing and "Yin" nourishing].

The "Qi" deficiency and "Yin" deficiency rats were fed with Chinese Taihe Chicken or common Chicken. The results showed: Chinese Taihe Chicken and common Chicken could all improve in part the "Qi" deficiency of rats caused by forced swimming, furthermore, the effect of Chinese Taihe Chicken was better than that of common Chicken. Chinese Taihe Chicken could obviously reduce the activity of adenosine triphosphatase of kidney tissue of "Yin" deficiency rats caused by injecting thyroxine. It suggested that Chinese Taihe Chicken could nourish the "Yin".

Adenosine Triphosphate↗
PubMed1999

[Establishment of a chemotherapeutic agents-induced apoptosis model of retinoblastoma].

OBJECTIVE: To determine the apoptotic effects of different chemotherapeutic agents on the retinoblastoma(RB) cell line HXO-RB44 and to establish a drug-induced apoptosis model of RB in vitro as the basis for further research on the mechanism of drug-induced apoptosis and spontaneous regression of RB. METHODS: Twelve chemotherapeutic agents, including vincristine, cytarabin, methotrexate, cyclophosphamide, thiotepa, mitoxantrone, aclanomycin, pirarubicin, cisplatin, carboplatin, mitomycin, etoposide, of different concentration (10(-9), 10(-8), 10(-7), 10(-6), 10(-5), 10(-4) mol.L-1) were employed into HXO-RB44 cell line respectively for 24 hours, then apoptotic effects on it were decided by observing the DNA ladders on agarose gel electrophoresis. After that, one chemotherapeutic agent with the most evident DNA ladders was applied into HXO-RB44 cell line for 4, 8, 16, 24, 48 and 72 hours respectively, and the DNA ladders on agarose gel were also surveyed. Apoptotic cells were identified with transmission electron microscopy. RESULTS: Typical DNA ladders were shown on agarose gel after HXO-RB44 cell line were exposed to 10(-6)-10(-5) mol.L-1 vincristine and 10(-5) mol.L-1 aclanomycin for 24 hours and the former were much clearer. No DNA ladders did emerge when the RB cells were treated by the rest ten chemotherapeutic agents. The DNA ladders began to appear when dealt with 10(-5) mol.L-1 vincristine for 8 hours, to be most obvious for 24 hours, and abated for 48 hours then disappeared for 72 hours. Amount of apoptotic RB cells were observed by transmission electron microscopy. CONCLUSION: Both vincristine and aclanomycin have the effect of inducing apoptosis on HXO-RB44 cell line, but that of vincristine is more forceful, which is time and concentration dependent. So vincritine is an ideal agent for establishing an apoptosis model of HXO-RB44 cell line.

Antineoplastic Agents↗
PubMed1999

[Possibility and clinical significance of reservation middle turbinate in endoscopic sinus surgery].

OBJECTIVE: To study the possibility and significance or reservation of the middle turbinate in endoscopic sinus surgery for sinusitis and/or nasal polyps. METHODS: (1) The morphology and mucosal ultrastructure of middle turbinate were observed preoperatively and postoperatively by nasal endoscopy and scanning electron microscopy in 20 cases; (2) The proportions of the septal turbinate formation and the closure of ethmoid sinus cavity were investigated postoperatively by nasal endoscopy in 60 cases with middle turbinate reserved and 60 cases with middle turbinate resected. RESULTS: (1) The morphology and mucosal ultrastructures of reserved middle turbinate were observed to have recovered postoperatively; (2) The proportions of the septal formation and the closure of ethmoid sinus cavity in the groups with middle turbinates reserved and resected were 13.3%, 18.3% and 58.3%, 51.7%, respectively (P < 0.01). CONCLUSION: It is possible that the structure of reserved middle turbinate may return to normal and it is important to save the middle turbinates to improve clinical cure rate.

Adolescent↗
PubMed1999

[Anatomic variations of the ostiomeatal complex and their correlation with chronic sinusitis: CT evaluation].

OBJECTIVE: To explore the relationship between anatomic variations in the ostiomeatal complex (OMC) and chronic sinusitis. METHODS: Coronal plane CT scans of the paranasal sinuses showing the ostiomeatal complex including the middle turbinate, uncinate, ethmoid bulla, agger nasi and Haller cell were analyzed in 297 individuals (594 sides). Statistical analyses were carried out with SPSS 5.0. RESULTS: There were 81.14% of OMC noted to have at least one variation. The anatomic variations included paradoxical curvature of the middle turbinate (13.97%), the pneumatized middle turbinate (34.85%), uncinate hyperplasia(19.36%), deviation of uncinate (45.27%), large ethmoidal bulla (30.30%), large agger nasi (0.70%) and Haller cell (1.00%). The correlation between variations and chronic sinusitis was significant (P < 0.01). CONCLUSION: The occurrence of OMC variation is common. The variations may be one of the causes of chronic sinusitis. Therefore, properly handling the variations was important in the endoscopic sinus surgery.

Adolescent↗
PubMed1999

[Spectral properties of broad emission bands of Cr3+ in A3M2Ge3O12 (A = Cd2+, Ca2+; M = AI3+, Ga3+, Sc3+) garnets].

The spectral properties of the Cr3+ broad emission band in A3M2Ge3O2 : Cr(A = Cd2+ ,Ca3+; M = Al3+,Ga3+,Sc3+) germanate garnets at room temperature are reported for the first time. In the order of Al3+ --> Ga3+ --> Sc3+ and Cd2+ --> C2z+ ions which occupy the octahedral and duodeahedral sites, respectively, R-NIR broad emission band of 4T2 --> 4A2 level transition, emission peak, and the spectral long wavelength and short wavelength sides of Cr3+ shift to long wavelengths having lower energy. The reason is that the crystal field strengths in the octahedral decrease, while the cation ionic radii in the A3M2Ge3O12 system garnets increase gradually. The R-NIR emission intensity of Cr3+ is increased with some Sc3+ ions substitution for Al3+ or Ga3+ ions in octahedral sites.

English Abstract↗
PubMed1999

[Determination of Si, P, Nb and Ti in steels by ICP-AES with offset profile additional lines].

This article introduced the increment of measurement channels for the elements silicon, phosphorus, niobium and titanium by changing the entrance slit angle, based on the fixed channels of the ICP-AES. The entrance slit angle was controlled by a motor. We determined trace silicon, phosphorus, niobium and titanium in steels, and examined the detection limits, accuracy and precision, and the results were satisfactory. With this method, we could also determine other elements, and widened the applied range of ICP-AES.

English Abstract↗
PubMed1999

[Indirect determination of industrial chlordane by ultraviolet spectrometry].

Toxicity in chlordane is in proportion to the content of hexachlorocyclopentadiane. Choosing acetone as the solvent, we determined that content by ultraviolet spectrometry, and then calculated roughly the content of this industrial chlordane. The method is cheaper, more rapid than gas chromatography, and suited to rapid testing industrial chlordane.

Chlordan↗
PubMed1999

[Luminescence character of Ce3+ in rare earth borate glasses].

Ce3+ doped rare earth borate glasses (BLBL:Ce3+) were synthesized. The excitation and emission spectra and fluorescence decay curves of BLBL:Ce3+ were measured at room temperature. In BLBL:Ce3+ glasses, Ce3+ emits strong purplish-blue light. The results of analyzing spectra and fluorescence lifetime show that there are two kinds of Ce3+ luminescence centres in this kind of rare earth borate glasses. Ce3+ doped rare-earth glasses is a kind of beneficial supplement for Ce3+ fluorescence glasses system.

English Abstract↗
PubMed1998

Mutations that induce constitutive activation and mutations that impair signal transduction modulate the basal and/or agonist-stimulated internalization of the Lutropin/Choriogonadotropin receptor.

Previous results from this laboratory suggested that the same active conformation of the lutropin/choriogonadotropin receptor (LHR) is involved in the stimulation of G proteins and in triggering the internalization of the bound agonist. We have now analyzed two naturally occurring, constitutively active mutants of the human LHR. These mutations were introduced into the rat LHR (rLHR) and are designated L435R and D556Y. Cells expressing rLHR-D556Y bind human choriogonadotropin (hCG) with normal affinity, exhibit a 25-fold increase in basal cAMP and respond to hCG with a normal increase in cAMP accumulation. This mutation does not affect the internalization of the free receptor, but it enhances the internalization of the agonist-occupied receptors approximately 3-fold. Cells expressing rLHR-L435R also bind hCG with normal affinity, exhibit a 47-fold increase in basal cAMP, and do not respond to hCG with a further increase in cAMP accumulation. This mutation enhances the internalization of the free and agonist-occupied receptors approximately 2- and approximately 17-fold, respectively. We conclude that the state of activation of the rLHR can modulate its basal and/or agonist-stimulated internalization. Since the internalization of hCG is involved in the termination of hCG actions, we suggest that the lack of responsiveness detected in cells expressing rLHR-L435R is due to the fast rate of internalization of the bound hCG. The finding that membranes expressing rLHR-L435R (a system where internalization does not occur) respond to hCG with an increase in adenylyl cyclase activity supports this suggestion.

Adenylyl Cyclases↗
PubMed1998

A Plasmodium falciparum novel gene encoding a coronin-like protein which associates with actin filaments.

Plasmodium falciparum, the major causative agent of human malaria, is an Apicomplexa protozoan parasite which invades in its intermediate host hepatocytes and erythrocytes. The driving force underlying internalization into the host cell is thought to involve both polymerization of parasite actin, as entry is inhibited by the cytochalasins, and an actin motor-associated protein. In the related Apicomplexa parasite, Toxoplasma gondii, the involvement of parasite actin during both processes of motility and host cell entry has been genetically established. In a search for molecules that can regulate actin dynamics within Apicomplexa parasites, we have identified a P. falciparum homologue of the actin associated protein called coronin originally described in the amoeba Dictyostelium discoideum. The single copy gene displays a strong homology with the amoeba sequence and with the bovine and human coronin homologues recently cloned. This homology lies not only within the N-terminus containing the five WD repeats that characterize coronin but also extends in the C-terminal part. Furthermore, using an affinity-purified mouse monoclonal antibody against D. discoideum coronin, we have detected in extracts of P. falciparum young and mature schizonts a 42-kDa polypeptide which binds this antibody and is present in a Triton insoluble fraction that also contains parasite actin filaments. In addition, the recombinant protein encoded by the homologue nucleotidic sequence of P. falciparum coronin is indeed recognized by the antibody against D. discoideum coronin. Finally, the cross-reactive polypeptide displays the ability to cosediment with exogenous F-actin, a property which fits with its involvement in actin dynamics.

Actins↗