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Biomedical subjects

Z Liu

Publications and source records attributed to Z Liu.

At least 325 records · Page 18Linked to original sources
PubMed2001

[Effect of various substrate nutrient on the spore germination and infective germ tube inducing of Pandora delphacis].

The influence of nutrients on spore germmination of P. delphacis was investigated using amino acids, fatty acids, carbohydrates, vitamins, minerals, and extracts of aphids or planthoppers. It was found that the formation of germ tubes from primary conidia was significantly stimulated by cysteine, asparagine, behenic acid (C22:0), trehalose, fructose, glycerol, maltose, ascorbic acid, thiamine(VB1), Folic acid, ZnSO4, FeSO4 and extracts of aphids and planthoppers. Of these many could suppress the formation of secondary conidia from primary conidia, e.g., cysteine, behenic acid (C22:0), myristic acid (C14:0), palmitic acid (C16:0), stearic acid (C18:0), arachidic acid (C20:0), lignoceric acid (C24:0), ascorbic acid, thiamine (VB1), riboflavin (VB2), folic acid, nicotinic acid, ZnSO4, and FeSO4. However, the nutrients not conducive to the formation of germ tubes were stimulants to the formation of secondary conidia. These included tyrosine, alanine, glucose, galactose, sucrose, glycogen, inositol, pyridoxal (VB6), NaCl, and KCl. Moreover, nutrients including asparagine, trehalose, glycerol, maltose, fructose, thiamine (VB1), and folic acid stimulated the formation of both germ tubes and secondary conidia. The result above indicated that the substrate nutrients which can stimulate the formation of germ tubes were general in planthoppers and aphids, it means the formation of aggressive germ tubes was one of important factors of successful for infection to the hosts. Of which it confirmed that the host specificity for P. delphacis against N. lungus and M. persicae.

Amino Acids↗
PubMed2001

[Composition and structure of bioflocculant BP25].

A strain of Bacillus megaterium screened from activated sludge could produce exocellular flocculant. The flocculant was purified through ethanol precipitation and Sephadex S-500 column chromatography. The purified flocculant BP25 was assayed by Bradford reaction, agarose gel electrophoresis and Sulfate-phenol method. The results showed that BP25 was a kind of polysaccharide which contains 36.97% O, 6.28% H, 47.00% C, 0% No NMR assay showed BP-25 contains no uronic acid. Gas-chromatography assay combined with thin-layer chromatography of acid hydralate revealed that BP25 contains Glucose and Mannose with the mole ratio of 4:1. Methylation analysis revealed the polysaccharide contains alpha-1, 6 glycosidicbond and alpha-1, 3 glycosidicbond. The main chains are comprised of Glucose and all the Mannose are in the side chains. Possible repeating unit structure was deduced.

Bacillus megaterium↗
PubMed2001

[The construction and application of promoter-signal peptide probe vector of lactic acid bacteria].

A promoter-signal peptide probe vector of lactic acid bacteria, designated pZLB based on pMG36e has been constructed. The vector contained a reporterd gene encoding for beta-lactamase, which lacked a promoter and a functional signal sequence. Sau3A restriction fragments (80-400 bp) from L. lactis ATCC 7962 total DNA were cloned into BamHI site of pZLB. A lot of different size framents were selected. These fragments promoted transcription and secretion of beta-lactamase in L. lactis. Sequence analysis revealed that inserted fragment in pZLBe7 contained typical promoter, SD sequence and atypical signal sequence.

Amino Acid Sequence↗
PubMed2001

[Effect of drying and temperature on the sporulation of Pandora delphacis mycelia gelatinized].

The entomophthoraceous fungus, Pandora delphacis, is a microbial agent highly potential for control of sucking-type insects. In this study, effort was made of gelatinizing the mycelia of the isolate F95129 from submerged culture using polyacrylamide-starch gel pwder and sodium alginate. The resulting film-like gel of the mycelia sporulated very well, indicating that the materials used for gelatinization of the mycelia was biologically compatible with P. delphacis. Then, the gelatinized mycelia were slowly dried in silica chamber at 4, 14, and 24 degrees C, respectively. After 35-day drying and storage in the chamber, however, a 22.7%-92.8% decrease of sporulation capacity occurred in the film-like gels, which then had different water content. The nutrient-supplemented polyacrylamide-starch gel stored at 14 degrees C with water content of 6.1%-7.4% was best for largely decreasing the loss of sporulation capacity among the combinations of gel, nutrition, water content and temperature. The results indicate that it could be possible to choose a desirable gel for longer biological activity of gelatinized P. delphacis mycelia.

Acrylic Resins↗
PubMed2001

[Changes and relations of leptin, growth hormone and insulin during puberty in obese and non-obese children].

In order to study the regularity of changing leptin, growth hormone (GH) and insulin (INS) during puberty and their relationships, a group of 300 obese and 300 non-obese children, aged 10-15 were selected. Leptin level increased with age and then decreased in boys, but it had only increasing tendency in girls. The GH level increased and then decreased suddenly in all groups. There was no obvious regularity in the change of INS. Serum leptin and INS levels were higher (P < 0.01) in obese children than that in non-obese children, while GH levels were significantly lower (P < 0.01) in obese boys. Results also showed that GH was negatively correlated with leptin in boys (obese group: r = -0.74, P < 0.05; non-obese group: r = -0.69, P < 0.05) and positively correlated with leptin in girls (obese group: r = 0.58, P < 0.05; non-obese group: r = 0.67, P < 0.01). There was a positive correlation between INS and leptin in non-obese girls (r = 0.54, P < 0.05). It is concluded that leptin might play an important role during the initial stage of puberty in children and the effect of leptin on pubescent development in girls is greater compared with boys. The correlation between leptin and GH are gender dependent in boys and girls, which may cause the timing differences of sudden growth in boys and girls.

Adolescent↗
PubMed2001

[An abzyme to catalytize the deiodination of thyroxine].

AIM: To mimic an important family of selenoenzymes in organism-thyroxine (T4) deiodinases and prepare a selenium-containing abzyme catalyzing deiodination of T4. METHODS: A anti-T4 monoclonal antibody was generated by hybridoma methodology and converted into a selenium-containing abzyme by the method of chemical modification. The catalytic activity of the enzyme was measured by RIA method. RESULTS: The abzyme displayed a marked activity of catalyzing deiodination of T4 and a higher specificity to the substrate T4 than that of natural enzyme, and the double reciprocal plots of the initial rates of T3 formation vs. T4 concentration yielded a family of parallel lines. The catalytic activity could be sensitively inhibited by 6-propyl-2-thiouracil (PTU), a competitive inhibitor for dithiothreitol (DTT). CONCLUSION: An abzyme with the diodination activity was first prepared and the reaction mechanism of the enzyme was bisubstrate ping-pong one.

Animals↗
PubMed2001

[The significance of nuclear factor kappa Bp65 (NF kappa Bp65) expression on the vascular endothelial cells of rectum adenocarcinoma of human].

OBJECTIVE: This study inquired into the mechanism of cancer vascular metastasis. METHODS: The immunohistochemical method was adopted in determining the expression of intercellular adhesion molecule-1 (ICAM-1) and nuclear factor kappa B (NF kappa Bp65) on the peritumoral rectum tissues and metastatic lymph nodes of 8 patients and on the rectum tissues and lymph nodes of 5 normal human subjects. Also, the method of in situ hybridization was employed in detecting the binding site of NF kappa Bp65 on vascular endothelial cells. RESULTS: It was found that the proteins of ICAM-1 and NF kappa Bp65 were expressed on the vascular endothelial cells of the rectum adenocarcinoma patients, and there was a NF kappa B binding consensus sequences on ICAM-1 promoter in the vascular endothelial cells of the rectum adenocarcinoma patients. When DIG-AKP labeled 38-bp oligonucleotide probe was used, there was no expression of ICAM-1 and NF kappa Bp65 on the vascular endothelial cells of the normal human lymph node and rectum tissues. CONCLUSION: The above data suggest that the activation of ICAM-1 promoter may critically depend on NF kappa Bp65 homodimers or heterodimers binding to a variant kappa B site on the vascular endothelial cells of human rectum adenocarcinoma. These may indicate the potential roles of NF kappa B in cancer metastasis, thus giving clues to the development of a novel anti-metastasis strategy.

Adenocarcinoma↗
PubMed2001

[The protein expression of Bcl-x1 and Bcl-2 in eosinophils in nasal polyps and the influence of beclomethasone dipropionate on the expression].

OBJECTIVE: To investigate the protein expression of B-cell lymphoma/leukemia-2(Bcl-2) and B-cell lymphoma/leukemia-x long(Bcl-x1) in eosinophils in nasal polyps and the influence of beclomethasone dipropionate on the expression. METHODS: Using May-Grünwald-Giemsa (MGG) method and immunohistochemical method, the protein expression of Bcl-x1 and Bcl-2 in eosinophils in nasal polyps from patients treated with beclomethasone dipropionate treatment and patients without any treatment was compared. RESULTS: (1) Nasal polyp tissues from patients without treatment had more eosinophils than those from patients with treatment(P < 0.01). (2) No protein expression of Bcl-2 was observed in all 52 patients. (3) 20.0% patients with treatment had the expression of Bcl-x1, whereas 48.1% patients without treatment had the expression. The difference between these two groups was significant(P < 0.05). CONCLUSION: These data suggest that Bcl-x1 may act as an anti-apoptotic molecule in eosinophils and corticosteroids induce eosinophil apoptosis through suppressing the expression of Bcl-x1.

Adolescent↗
PubMed2001

[Expression of alpha and beta subunit isoforms of Na, K-ATPase in the guinea pig endolymphatic sac].

OBJECTIVE: To investigate the expression and significance of alpha and beta subunit isoforms of Na, K-ATPase in the guinea pig endolymphatic sac. METHODS: The distribution of alpha and beta subunit isoforms of Na, K-ATPase in endolymphatic sac of guinea pig was identified by immunocytochemistry and in situ hybridization. RESULTS: The expression of Na, K-ATPase alpha and beta subunit isoforms varied among different cell regions of the endolymphatic sac. Epithelial cells of the endolymphatic sac were observed to contain the alpha 1, beta 1 and beta 2 subunit isoforms, and the expression of beta 2 was stronger than that of beta 1. Subepithelial cells contained alpha 1 and alpha 2 subunit isoforms and the expression of alpha 1 was stronger than that of alpha 2. No expression of alpha 3 subunit isoform was observed in endolymphatic sac. CONCLUSION: Na, K-ATPase of endolymphatic sac consists of different alpha and beta subunit isoforms which, working in concert, serve to maintain homeostasis in inner ear.

Animals↗
PubMed2001

[A preliminary study of a hearing screening model for newborn].

OBJECTIVE: To search for a hearing screening model for newborn and to investigate the prevalence of newborn hearing loss in our country. METHODS: The distortion product otoacoustic emissions (DPOAE) was used to test the hearing in 2,998 of 3,075 newborns before discharge. Otoacoustic emissions (OAE) was again used for cases failed in the hospital screening 4 weeks later. Those cases failed in both screening steps were finally tested by auditory brainstem response (ABR). All infants failed in ABR test received diagnostic evaluation audiologically to identify the category and degree of hearing loss. The pass criterion of DPOAE was defined as signal-noise-ratio (SNR) exceeding 6 dB in 4 of 5 frequencies between 1.5-6 kHz. The pass criterion of ABR was the presence of wave V in response to 35 dB nHL click stimuli. RESULTS: The OAE screening in the hospital showed that 2,710 (90.4%) newborns passed the first test. Two hundred and sixty three of 288 newborns passed the second OAE screening after one month. Six of 25 infants failed in ABR test were eventually identified to be hearing impaired. CONCLUSION: Two-stages screening, combining OAE and ABR tests, may be an ideal model for newborn hearing screening. The prevalence of congenital hearing loss is similar to that reported in the literature.

Evoked Potentials, Auditory, Brain Stem↗
PubMed2001

National survey on prevalence of cancer pain.

OBJECTIVE: To collect nationwide basic data about cancer related pain. METHODS: Sixty cancer patients in each province were randomly selected to participate in this survey. The subjects represented all stages of cancer, tumor sites, and different demographic characteristics. Two self-designed structured questionnaires including reasons, types of pain and pain management were used by patients and physicians respectively. Subjects were asked to report whether he/she had experienced any type of cancer related pain and filled out the equivalent questionnaire. The severity of pain was assessed by using "visual analogue scale". Original data input and analysis were using EPI-INFO software package. RESULTS: The result showed that 61.6% (958/1555) of patients had different types of cancer related pain. Majority of pain (85.1%) were caused by advanced cancer. The major reasons (64.4%) for poor management or impedimental factors of pain care are due to patient including over-concern on opioid analgesic addiction, reluctance to report pain or refused to use opioid analgesic until at times when pain is intolerable; 26.8% belonged to physician's reasons including fear to cause addiction on opioid and lack of knowledge about cancer pain management; 16.2% are due to lack of different kinds of opioid analgesic for use and 16.1% belonged to drug regulation. CONCLUSIONS: The results showed that majority of patients (61.6%) had different types of cancer related pain. In most of patients, cancer pain was relieved when they were treated. The major reason for under-treatment or impeded factors for effective relief of cancer pain was fear of opioid addiction by both medical professionals and patients.

Adolescent↗
PubMed2001

Identification of glucose transporter-1 and it's functional assay in mouse glomerular mesangial cells cultured in vitro.

OBJECTIVE: To evaluate the role of glucose transporter-1 (GLUT1) in the glucose uptake of glomerular mesangial cells. METHODS: Cultured C57/SJL mouse mesangial cells were used in the study. The expression of GLUT1 mRNA was detected by RT-PCR. The expression of GLUT1 protein was detected by immunofluorescence and flow cytometry. The uptake of glucose and its kinetics were determined by 2-deoxy-[3H] -D-glucose uptake. RESULTS: Both GLUT1 mRNA and protein were found in mouse glomerular mesangial cells. 2-deoxy-D-glucose uptake and kinetics assay showed that this glucose transporter had high affinity for glucose and the glucose uptake specificity was further confirmed by phloretin. CONCLUSION: Functional GLUT1 did present in mouse mesangial cells cultured in vitro and it might be the predominant transporter mediated the uptake of glucose into mesangial cells.

Animals↗
PubMed2001

Laparoscopic myomectomy.

OBJECTIVE: To investigate the indications, surgical techniques and complications of laparoscopic myomectomy. MATERIALS AND METHODS: A retrospective study was carried out in 74 patients with fibroids > 3 cm from March, 1995 until May, 2000 at PUMC Hospital. Indications for surgery were symptomatic fibroids (20 cases), mainly pain or urine frequency; progressively increasing fibroid size (7 cases); coexistent adnexal pathology(26 cases) and infertility(21 cases). RESULTS: The number of fibroids of each patient varied from 1 to 4 with single fibroid of 62 cases (83.7%). The fibroids were located in anterior wall (30 cases), posterior wall (23 cases) and fundus (21 cases). A total of 93 fibroids were removed from these patients including 16 intramural fibroids and 77 subserous fibroids. The size of dominant fibroids ranged from 3 approximately 8 cm (mean 4.8 cm). In 19 cases (25.6%), the uterine wall was sutured in one layer. Mean duration of operation was 73 minutes and mean blood loss was 82 ml. Longer operating time and more blood loss were observed in patients with fibroids > or = 4 cm than those with fibroids < 4 cm. The difference was statistically significant ( P < 0.05). Mean postoperative hospital stay was 3.2 days and overall complication rate was 1.4%. The average postoperative follow-up period was 22 months (1 approximately 62 months). All the patients with symptoms showed remission of their complaints at 2-month follow-up. Recurrence of fibroid occurred in 1 case 1 year after initial operation and second laparoscopic myomectomy was given to her successfully. Five patients became pregnant. The pregnancy was uneventful and proceeded to selective caesarean section at term pregnancy in 4 cases. One miscarriage occured at 8 weeks in the 5th case. No adhesions at myomectomy site were found in these 5 patients. CONCLUSIONS: Our study suggests the feasibility of laparoscopic myomectomy in selected patients, which leads to effectiveness, low complication rate and satisfactory remission of symptoms. Further study on recurrence and fertility must be continued.

Adult↗
PubMed2001

[Raman analysis of SiGe films grown by UHV/CVD].

This paper presents a Raman method, which is no deconstructed, to measure Ge content and strain in SiGe alloy films and some samples, which is grown by UHV/CVD with different Ge content and thickness, have been tested by above method. Two samples among them were measured by DCXRD, the results tested by DCXRD are consistent with Raman results that proves that the method in this paper is reliable and accurate. The SiGe PHMOSFET has been fabricated by the samples, the transconductance reaches 112 ms.mm-1 for the device with 0.5 micron channel.

Alloys↗
PubMed2001

[The synthesis, Raman, FTIR spectra and characteristic of Rb(NTO).(H2O)].

A new coordination compound of Rb(NTO).(H2O) were synthesized by reaction of NTO water solution with Rb2CO3. The composition of this compound was defined by elemental analysis of C, H and N and quantitative analysis of Rb. The structure and properties were characterized by FTIR spectra Raman spectra, and X-ray powder defferaction, and the different bonds formed. In the molecule of Rb(NTO).(H2O) has been tried to discuss.

English Abstract↗
PubMed2001

[Surface characteristic of domestic poly-DL-lactic acid membrane for periodontal guided tissue regeneration].

OBJECTIVE: To evaluate the surface characteristic of domestic poly-DL-lactic acid membrane for periodontal guided tissue regeneration. METHODS: Three guided tissue regeneration membranes (PDLLA, ePTFE, COL)were implanted in rats subcutaneously, then they were removed 2,4,8 weeks after surgery for examination under scanning electron microscope. The membranes in vitro served as control. RESULTS: The surface of PDLLA membrane was characterized by unorganized smooth film structure. After 2 weeks implanted subcutaneously, its surface became rough with numerous oval micropores in it. These oval micropores were 5 microm in size.The micropores increased gradually in size and number 4, 8 weeks after implantation,there were many shindle shaped cells inlayed. CONCLUSION: Domestic Poly-DL-lactic acid membrane exhibits excellent biocompatibility,which meets the criterion for GTR.

English Abstract↗