Biomedical subjects

Bei Zhang

Publications and source records attributed to Bei Zhang.

33 records · Page 2Linked to original sources

PubMed2005

[Optical penetrating keratoplasty in eyes with severe keratomycosis after therapeutic keratoplasty].

OBJECTIVE: To observe and evaluate secondary optical penetrating keratoplasty (PKP) in the eyes with severe keratomycosis after therapeutic keratoplasty using cryopreserved donor tissue. METHOD: There were 35 eyes in 35 cases for whom therapeutic PKP using cryopreserved donor tissue had been carried out to treat severe fungal keratitis. At least 6 months after the PKP, when the fungal infection had been eradicated and ocular inflammation had resolved, a secondary optical penetrating keratoplasty was further performed for visual rehabilitation. If the crystal lens was found to be opaque, it was also simultaneously removed through extracapsular cataract removal with an IOL implantation. Surgical or postoperative complications, visual outcome, graft rejection episode, and graft survival were analyzed. RESULTS: Among 35 eyes, 18 eyes received optical PKP only, and 17 received combined optical PKP with ECCE and IOL implantation. During the follow-up period of 6.8 - 36.8 (15.7 +/- 7.6) months after optical PKP, 3 eyes experienced graft failure due to immunologic rejection and 32 retained clear grafts. Postoperative visual acuity was 0.4 or better in 24 eyes, and 0.1 or better in 32 eyes, and less than 0.1 in 3 eyes. CONCLUSIONS: Optical PKP performed in the eyes after therapeutic PKP due to severe fungal keratitis can recover satisfactory visual acuity, with low frequency of graft rejection, long-term graft survival and few complications.

Adult↗

PubMed2004

Kirby-Bauer disc approximation to detect inducible third-generation cephalosporin resistance in Enterobacteriaceae.

Resistance to beta-lactam antibiotics in enteric Gram-negative bacilli may be difficult to detect using standard methods of either Kirby-Bauer disc diffusion (KBDD) or broth dilution for minimal inhibitory concentration (MIC). This difficulty is due to genetic differences in resistance determinants, differences in levels of gene expression, and variation in spectra of enzymatic activity against the substrate beta-lactams used for susceptibility testing. We have examined 95 clinical isolates reportedly susceptible to ceftazidime and ceftriaxone, as originally determined by either KBDD or MIC methods. The organisms studied here were isolated in 2002 from two pediatric hospital centers (Seattle, USA and Shanghai, China). They belong to the inducible beta-lactamase producing Gram-negative bacilli, such as Enterobacter spp., Citrobacter spp., Serratia spp., Morganella spp., Providencia spp., and Proteus vulgaris. A Kirby-Bauer disc approximation (KBDA) method identified inducible phenotypes of third-generation cephalosporin resistance in 76% of isolates, which would otherwise be considered susceptible by standard KBDD methods.

Journal Article↗

PubMed2004

Chemical modification of glycerinated stalks shows tyrosine residues essential for spasmoneme contraction of Vorticella sp.

Chemical modification of glycerinated stalks of Vorticella with TNM is used to investigate the role of tyrosine residues in the Ca(2+)-induced contraction of the spasmoneme. Tetranitromethane (TNM) is often employed as a specific reagent for the nitration of tyrosine residues in a protein at neutral and slightly alkaline pHs although TNM can also oxidize cysteine residues in the acidic and neutral pH range. Prior incubation with Ca(2+) of stalks to be treated with TNM can protect the spasmoneme from irreversible denaturation. On the other hand, TNM treatment in the absence of free Ca(2+) causes an irreversible denaturation of the spasmoneme. It was revealed by us that an isolated Ca(2+)-binding protein called spasmin could not bind with Ca(2+) after TNM treatment, even if the treatment was performed in the presence of Ca(2+). In an additional experiment, we confirmed that the chemical modification of cysteine residues in the spasmoneme with N-7-dimethyl-amino-4methyl- coumarinyl- maleimide (DACM) has no effect on the contractibility. These results suggest that tyrosine residues in spasmin are essential for spasmoneme contraction and are protected from TNM in the presence of Ca(2+) when spasmin binds with its receptor protein in the spasmoneme.

Animal Structures↗

PubMed2004

[Clinical observation on prevention of "jia wei si jun zi tang" from damage of hepatic reserving function after intervention of liver cancer].

OBJECTIVE: To observe prevention of "Jia Wei Si Jun Zi Tang" (JWSJZT) from damage of hepatic reserving function after intervention of liver cancer. METHODS: 65 patients with advance stage of liver cancer were randomly into two groups, the control group (regular protective therapy) and the treatment group (regular protective therapy + JWSJZT). There were 33 and 32 cases in the control group and treatment group,respectively. ICGR15 was detected before the first and the second intervention treatment and one month after the second intervention treatment, respectively. ICGR15 change was observed before and after the intervention treatment in the two groups. RESULTS: ICGR15 was 11.13% +/- 7.28% in the treatment group and 11.81% +/- 7.43% in the control group (P > 0.05) before the first intervention; 18.36% +/- 9.82% in the control group and 12.18% +/- 5.22% in the treatment group, before the second invention treatment (P < 0.05); 19.12% +/- 9.96% in the control group and 12.83% +/- 5.28% in the treatment group one month after the second intervention treatment (P < 0.05). CONCLUSION: The western medicine + JWSJZT group is superior in curative effect to western medicine group.

Adult↗

PubMed2004

[Observation of clinical response of "sheng ban recipe" for platelets decrease after chemotherapy].

BACKGROUND & OBJECTIVE: The majority of cancer chemotherapy can lead to bone marrow depression, which often affects clinical response as chemotherapy can not be carried out with enough dosage on time. The platelets decrease is one of the problems caused by bone marrow depression. Though the clinical response of hyodermic "IL-11" is affirmed to advance platelets presently, it is limited by expensive price. Other agents that can be taken orally with suitable price and equal authenticity are less reported. The author observed clinical response of platelets decrease adopting traditional Chinese medicine "Sheng Ban Recipe"(SBR). METHODS: Totally 103 patients with platelets decrease after chemotherapy from July 1994 to Jannary 2002. They were randomly divided into two groups: SBR plus common treatment group and common treatment alone group. The previous group take 1 package SBR for twice drink per day. Common treatment group give common therapy only. The follow-up period is 2 weeks. RESULTS: Among the 55 cases in SBR group, noticeable efficiency 20%, efficiency 50.9%, total efficiency 70.9%, which is evidently superior to common group. CONCLUSION: "Sheng Ban Recipe" can effectively treat thrombocytopenia after chemotherapy, which helps to reduce the necessary of intravenous drip of platelets and the risk of hemorrhage.

Adult↗

PubMed2003

Chemical modification of contractile 3-nm-diameter filaments in Vorticella spasmoneme by diethyl-pyrocarbonate and its reversible renaturation by hydroxylamine.

A peritrich ciliate possesses a zooid and a long stalk consisting of a bundle of 3-nm-diameter filaments. Glycerinated stalks can contract in the presence of free Ca(2+) and re-extend in the absence of free Ca(2+). In the present study, we demonstrated that histidine residue(s) played a critical role in spasmoneme contraction by using glycerinated stalk of Vorticella. Concentration-dependent inhibition of spasmoneme contraction was observed in the presence of reversible histidine-modifying reagent named diethyl-pyrocarbonate (DEPC). In addition, the contractility degree of DEPC-modified spasmoneme could be partially restored by hydroxylamine treatment. The 244nm absorption of modified spasmoneme protein(s) increased with rising DEPC concentration and decreased following the addition of hydroxylamine treatment. Adding Ca(2+) before DEPC modification could prevent the spasmoneme contraction from inhibition of DEPC. Those results suggested that histidine residues were actively involved in spasmoneme contraction. Ca(2+)-binding ability of spasmin was not inhibited by DEPC modification, which suggested that the essential histidine residues were not on the calcium-binding site of spasmin.

Animals↗

PubMed2003

SWI/SNF unwraps, slides, and rewraps the nucleosome.

The structure of the SWI/SNF-remodeled nucleosome was characterized with single base-pair resolution by mapping the contacts of specific histone fold residues with nucleosomal DNA. We demonstrate that SWI/SNF peels up to 50 bp of DNA from the edge of the nucleosome, translocates the histone octamer beyond the DNA ends via a DNA bulge propagation mechanism, and promotes the formation of an intramolecular DNA loop between the nucleosomal entry and exit sites. This stable altered nucleosome conformation also exhibits alterations in the distance between contacts of specific histone residues with DNA and higher electrophoretic and sedimentation mobility, consistent with a more compact molecular shape. SWI/SNF converts a nucleosome to the altered state in less than 1 s, hydrolyzing fewer than 10 ATPs per event.

Adenosine Triphosphate↗

PubMed2003

Defensin expression by the cornea: multiple signalling pathways mediate IL-1beta stimulation of hBD-2 expression by human corneal epithelial cells.

PURPOSE: To investigate the expression of human beta-defensins (hBDs) by human corneal epithelium and determine the effects of proinflammatory cytokines on expression of human beta-defensin (hBD)-2 by human corneal epithelial cells (HCECs) in culture. METHODS: RNA was extracted from corneal epithelial cells scraped from cadaveric corneas and from cultured HCECs, and RT-PCR was performed to detect hBD-1, -2, and -3 mRNA. To study the effects of proinflammatory cytokines on expression of defensin, HCECs were cultured and then exposed to interleukin (IL)-1beta or tumor necrosis factor (TNF)-alpha for up to 36 hours, with a range of concentrations (0.01-100 ng/mL). In some experiments, cells were pretreated with various cell signaling pathway inhibitors before the addition of IL-1beta. At the end of the incubations, the cells were harvested for RT-PCR and the culture media collected for the detection by immunoblot analysis of secreted defensin peptide. RESULTS: All epithelial tissue collected from cadaveric corneas expressed mRNA for hBD-1. hBD-2 was detectable in two of eight donors corneas, whereas hBD-3 was detected in five. All primary cultures of HCECs expressed hBD-1 and -3. A faint band for hBD-2 was detectable in three of eight cultures. Cultures of simian virus (SV)40-transformed HCECs always expressed hBD-1 and -3, but did not express hBD-2 under control conditions. IL-1beta and TNFalpha each stimulated the expression of hBD-2 in HCECs and were more effective in combination than alone. The effects of IL-1beta were concentration- (maximal at 10 ng/mL) and time-dependent (maximal at 12 hours and 24 hours for hBD-2 mRNA expression and protein secretion, respectively). The upregulation of hBD-2 mRNA persisted for at least 24 hours after removal of IL-1beta. The NFkappaB inhibitors pyrrolidinedithiocarbamate (PDTC; 100 microM), caffeic acid phenethyl ester (CAPE; 90 microM), and MG-132 (25 microM), blocked IL-1beta-stimulated expression of hBD-2. The p38 mitogen-activated protein (MAP) kinase inhibitor SB203580 (5 microM) and the c-Jun NH2-terminal kinase (JNK) inhibitor SP600125 (25 microM) partially blocked (by 47% and 59%, respectively) the effect of IL-1beta. However, PD98059, an ERK inhibitor, had no effect. Genistein (50 microM) and dexamethasone (1 microM) also partially blocked (by 26% and 28%, respectively) the effect of IL-1beta. CONCLUSIONS: Human corneal epithelium expresses hBD-1 and -3. hBD-2 is not typically present, but its expression can be stimulated by proinflammatory cytokines such as IL-1beta, acting through mitogen-activated protein (MAP) kinase and nuclear factor (NF)-kappaB pathways. Because IL-1 is known to be increased at the ocular surface after injury, the current observations provide a mechanism to explain the previous finding that hBD-2 is upregulated in regenerating corneal epithelium. Cytokine stimulation of hBD-2 expression most likely provides additional protection against infection and raises the possibility that this defensin in particular may be involved in the wound-healing response, per se.

Aged↗

PubMed2003

[Preliminary report of semimonthly 5-fluorouracil/leucovorin combined with paclitaxel in treatment of advanced gastric cancer (AGC)].

BACKGROUND & OBJECTIVE: Phase II clinical trails showed that paclitaxel is effective in treatment of advanced gastric cancer (AGC). The combination of paclitaxel and 5-fluorouracil (5-FU) in the treatment of advanced gastric cancer is effective and safe. This study was designed to evaluate the efficacy and the toxicity of paclitaxel combined with semimonthly 5-FU/Leucovorin for the AGC patients. METHODS: Twenty-five measurable patients with AGC proved pathologically were enrolled into this study. The chemotherapy regimen was comprised of paclitaxel,75 mg/m(2) i.v. in a 3-hour infusion followed by 2-hour infusion of leucovorin 200 mg/m(2), then 10-minute intravenous bolus of 5-FU 375 mg/m(2), then 48-hour infusion of 5-FU 2.8 g/m(2) using an ambulatory pump. The regimen was given per 14 days. One cycle consisted of twice chemotherapy regimens. All enrolled patients received at least two cycles of treatment. RESULTS: After two cycles of chemotherapy, the complete remission and the partial remission were 8% and 60%, respectively. The median duration of response was 4 months. No treatment-related death occurred. Phlebitis,feeling disorder, and alopecia were main side effects. CONCLUSION: Semimonthly 5-FU/LV combined with paclitaxel has high release rate but comparatively mild toxicity for AGC patients.

Adult↗

PubMed2003

[Clinical study in prophylactic use of chinese medicine to prevent chemoradiotherapy induced mucositis in nasopharyngeal carcinoma].

BACKGROUND & OBJECTIVE: Oropharyngeal mucositis is the most common acute non-hematology toxicity in nasopharyngeal carcinoma (NPC) treated with radiotherapy, especially in the concomitant chemoradiotherapy of local advanced NPC patients. This study was designed to observe the effect of traditional Chinese medicine against acute oropharyngeal mucositis from chemoradiotherapy in patients with local advanced NPC. METHODS: A total of 101 patients in stage III- IVa (Fuzhou 1992) were enrolled into this prospective randomized clinical trial. The cases were divided into treatment group (52 cases) and control group (49 cases). The median doses were 70.31+/-1.21 Gy for the treatment group and 70.78+/-1.95 Gy for the control group, respectively. Chemotherapy was concomitant with radiotherapy [single agent cisplatin (DDP,30 mg/m(2)) 6 times from first to sixth week of radiotherapy duration]. The patients of treatment group took 5-8 times of Chinese medicine daily and those of control group took 5-8 times of Dobell's solution daily.The observation indices included the degree of oropharyngeal and hematological toxicity, radiotherapy duration, and curative effect. RESULTS: (1)Oropharyngeal toxicity: there was no 0 degree oropharyngeal toxicity in both groups, I degree toxicity in 29 cases (55.77%) and 2 cases (4.08%), II degree toxicity in 18 cases (34.62%) and 17 cases (30.69%), III degree toxicity in 5 cases (9.62%) and 22 cases (44.89%), IV degree toxicity in 0 case (0%) and 8 cases (16.33%); there was statistical significance of difference between the two groups (P=0.000). (2)Hematological toxicity: there was no IV degree hematological toxicity in both groups. WBC toxicity (Z=-0.604,P=0.546), neutrophilic granulocyte toxicity (Z=-0.226,P=0.821), and platelet toxicity (Z=-0.099,P=0.922) were compared; there was no statistic significance of difference (P >0.05); (3)Radiotherapy duration: The radiotherapy duration of two groups were 49.79+/-1.83 days and 51.00+/-4.46 days; there was no statistic significance of difference (P=0.082). (4)Curative effects: The curative effects of two groups were:complete remission (CR) 76.92% (40/52) and 69.39% (34/49), partial remission (PR) 23.08% (12/52) and 30.61% (15/49); there was no statistical significance of difference (P=0.392). CONCLUSION: Chinese medicine was effective in reducing acute oropharyngeal toxicity resulting from chemoradiotherapy in patients with local advanced NPC. Furthermore, the apparent side effects of Chinese medicine in this study have not been observed. Chinese medicine treatment did not affect the short-term clinical outcome.

Acute Disease↗

PubMed2003

[Metabolic flux analysis of L-Tryptophan biosynthesis].

The metabolic flux balance model of L-Try synthesis by Corynebacterium glutamicum was constructed in this paper. Using this model, the metabolic flux distribution during the middle and late period were determined and the optimal flux distribution were calculated by linear program of MATLAB software. The analysis results indicate that 24.85% metabolic flux entered the HMP pathway and 75.15% entered the EMP cycle. But comparing to the optimal flux distributions, the production of L-Try should be improved from the genetic manipulation and fermentation control through reducing byproduct of amino acid and decreasing the metabolic flux of TCA and EMP.

Biosynthetic Pathways↗

PubMed2002

Autologous limbal grafting combined with deep lamellar keratoplasty in unilateral eye with severe chemical or thermal burn at late stage.

PURPOSE: To evaluate the efficacy of autologous limbal transplantation (ALT) combined with deep lamellar keratoplasty (DLK) for ocular surface reconstruction and corneal clarity recovery in eyes with severe late-stage chemical or thermal burns. DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: Thirty-nine eyes of 39 patients with a history of severe chemical or thermal burns over 6 months (mean, 47 +/- 28.7 months) exhibiting corneal vascularization, conjunctivalization, and heavy corneal scarring were treated at two university hospitals. METHODS: Surgical procedures included excising epibulbar fibrous tissue, clearing the fibrovascular membrane over the cornea, deep removal of corneal stroma 7.5 to 8.0 mm in diameter, exposing Descemet's membrane in the pupillary area, grafting a corneal button, transplanting autologous limbal and conjunctival epithelial grafts, and making a temporary tarsorrhaphy. MAIN OUTCOME MEASURES: Integrity of ocular surface recovery, postoperative corneal epithelial stability, optical corneal clarity, and best-corrected visual acuity were the outcome measurements. RESULTS: Thirty-four of 39 eyes that received ALT combined with DLK met the criteria of the study. Of 34 operated eyes, full corneal epithelialization was achieved in 19 eyes (55.9%) within 5 days and in 32 eyes (94.1%) within 7 days after surgery. Delayed epithelial healing occurred in two eyes (5.9%). The reconstructed corneal surface remained stable, and the renewed epithelium was characterized cytologically by nonkeratinized squamous cells without goblet cells. After surgery in 11 of 34 eyes, fluid was identified between Descemet's membrane and the donor corneal graft, resulting in a pseudochamber that completely resolved in 10 eyes within 30 days. In one patient, a persistent pseudochamber was present for 28 months. After surgery, transparent cornea especially in the pupillary area was accomplished in 29 eyes, whereas mild cornea clouding, nebulomacular corneal opacity, and heavy corneal scarring were observed, respectively, in three eyes. In addition, corneal endothelial decompensation was identified in two eyes and demonstrated persistent corneal epithelial and stromal edema. Remarkable improvement of postoperative vision was achieved in 30 eyes. Four eyes without postoperative improvement in vision were regrafted by penetrating keratoplasty at least 6 months after the original ALT and DLK surgery. CONCLUSIONS: Autologous limbal grafting combined with DLK simultaneously can restore a normal and stable ocular surface, create clear central cornea, and remarkably enhance visual acuity after severe chemical or thermal burns.

Adolescent↗

PubMed2002

[Application of impression cytology in diagnosis of ocular surface diseases]

OBJECTIVE: To evaluate the usefulness of impression cytology in diagnosing of ocular surface diseases. METHODS: Impression cytology was performed on 18 eyes with Sjgren's syndrome (dacryosialo-adenopathia atrophicans), 23 eyes with non-Sjgren's syndrome, 15 eyes after thermal or chemical burn at the scarred stage and 20 normal eyes. Conjunctival goblet cell density, conjunctival epithelial squamous metaplasia and corneal cytological features were evaluated respectively. RESULTS: In impression cytology, eyes of Sjgren's syndrome demonstrated a significantly higher grade of squamous metaplasia and lower goblet cell density (P<0.05) as compared with normal eyes and with eyes of non-Sj gren's syndrome in the bulbar conjunctiva, whereas no statistically significant difference of squamous metaplasia grade or goblet cell density was found in the palpebral conjunctiva (P>0.05) in these two groups. In thermal or chemical burned eyes at the scarred stage, the inferior, nasal and temporal bulbar conjunctiva showed higher conjunctival goblet cell density than in the normal eyes (P<0.01). Before surgery of ocular surface reconstruction, conjunctival goblet cells were detected on the corneal area in the 8 thermal or chemical burned eyes. However, the goblet cells in the corneal area of 7 burned eyes were completely resolved after successful ocular surface reconstruction. CONCLUSION The demonstrations of impression cytology in Sjgren's syndrome, thermal or chemical burn are distinctive. Impression cytology is a noninvasive,quick,easy and inexpensive technique, being a useful tool for diagnosis of ocular surface diseases.

Journal Article↗

PubMed2002

[Treatment of hepatic functional reserve injury after TACE in hepatocellular carcinoma with Chinese herbal medicines].

BACKGROUND & OBJECTIVE: Transcatheter arterial chemoembolization (TACE) has been proved to injure hepatic functional reserve. The current study was designed to evaluate the effect of Chinese herbal medicines in treatment of hepatic functional reserve injury after TACE. METHODS: Sixty-one advanced hepatocellular carcinoma patients were divided into two groups: groups A (Western medicine combined with Chinese herbal medicine group, n = 30) and group B (Western medicine group, n = 31). Western medicines were used to protect hepatic function and alleviate TACE syndrome in both group A and group B. Invigorating the spleen and activating blood circulation Chinese herbal medicines were added only in group A before and after TACE. Retention rate of Indocyanine green at 15 minutes (ICGR15) was measured in both group A and group B before 1st, 2nd TACE and one month after 2nd TACE respectively. RESULTS: Hepatic functional reserve before 1st TACE was 11.18% +/- 7.30% in group A and 11.83 +/- 7.18% in group B, (P > 0.05). Hepatic functional reserve before 2nd TACE was 11.69% +/- 5.13% in group A and 16.64 +/- 10.15% in group B, (P < 0.05). Hepatic functional reserve one month after 2nd TACE was 11.53% +/- 5.30% in group A and 19.80 +/- 11.26% in group B, (P < 0.05). CONCLUSIONS: Invigorating the spleen and activating blood circulation Chinese herbal medicine can prevent hepatic functional reserve injury after TACE.

Adult↗

PubMedDate not supplied

Exenatide elicits sustained glycaemic control and progressive reduction of body weight in patients with type 2 diabetes inadequately controlled by sulphonylureas with or without metformin.

BACKGROUND: In two placebo-controlled 30-week trials, treatment with exenatide reduced HbA(1c) and body weight in patients with type 2 diabetes in the context of sulphonylurea (SU) or SU plus metformin (MET) as background treatment. This analysis examines the effects of 82 weeks of exenatide treatment for participants in these earlier 30-week trials. METHODS: Data were pooled from the two pivotal trials of exenatide added to SU or SU plus MET. Both 30-week, placebo-controlled trials of 5 microg or 10 microg exenatide b.i.d. were followed by 52-week open-label, uncontrolled extension studies in which all participants received 10 microg exenatide b.i.d. and continued prior oral therapies. This interim analysis includes data for 222 patients who completed 82 weeks of exenatide treatment (61% M, age 57 +/- 10 y, weight 99 +/- 21 kg, BMI 34 +/- 6 kg/m(2), HbA(1c)8.4 +/- 1.0% [mean +/- SD]). RESULTS: Reduction in HbA(1c) from baseline to week 30 (-0.8 +/- 0.1% and -1.0 +/- 0.1% for 5 microg b.i.d. and 10 microg b.i.d., respectively [mean +/- SE]) was sustained up to week 82 (-1.0 +/- 0.1%). Of 207 patients with baseline HbA(1c) > 7%, 44% achieved HbA(1c) < or = 7% at week 82. Reduction of body weight from baseline to week 30 (-1.4 +/- 0.3 kg and -2.1 +/- 0.3 kg for 5 microg b.i.d. and 10 microg b.i.d., respectively) was progressive up to week 82 (-4.0 +/- 0.3 kg). The most frequent adverse events were nausea and hypoglycaemia, both generally mild to moderate in intensity. CONCLUSIONS: Exenatide added to maximally effective doses of SU or SU plus MET resulted in a sustained reduction in HbA(1c) and a progressive reduction in weight over 1 1/2 years.

Adolescent↗