[Research advances on the role and mechanism of chitosan-based wound dressing in wound healing]

The skin is the first barrier to maintain the stability of internal environment of the body and resist harmful factors of external environment, and is easily damaged because of various external factors. When full-thickness skin defects reach a certain level, it is difficult for the skin to repair itself, so wound dressings are needed to promote wound healing. Seeking an ideal dressing that can promote wound healing has long been a hot research topic. Chitosan is a unique biopolysaccharide polymer with good biocompatibility, biodegradability, antibacterial activity, and thermal stability, which has great potential in the development and application of wound dressings. Based on the introduction of properties of chitosan, this article reviews the role and mechanism of chitosan-based wound dressings in wound healing, and summarizes the hemostatic effect, antibacterial effect, delivery effect, and tissue regeneration promotion effect of chitosan, aiming to provide a certain reference for the research and development of new chitosan-based wound dressings in the future.

[Prevalence and risk factors of Giardia lamblia infections among colorectal cancer patients in Henan Province]

OBJECTIVE

To investigate the epidemiological characteristics and identify the risk factors of Giardia lamblia infections among patients with colorectal cancer in Henan Province.

METHODS

A cross-sectional study was performed for questionnaire surveys among colorectal cancer patients in Henan Cancer Hospital during the period from March to July, 2021. Patients' stool samples were collected, and the triosephosphate isomerase (tpi) gene of G. lamblia was amplified in stool samples using nested PCR assay to characterize the parasite genotype. Univariate analysis and multivariate logistic regression analyses were employed to identify the risk factors of G. lamblia infections among colorectal cancer patients.

RESULTS

A total of 307 colorectal cancer patients were investigated, including 176 males (57.3%) and 131 females (42.7%). PCR assay detected 8.1% [95% confidential interval (CI): (0.056, 0.117)] prevalence of G. lamblia infections among the study subjects, and there was no significant difference in the prevalence between men [9.1%, 95% CI: (0.057, 0.143)] and women [6.9%, 95% CI: (0.037, 0.125)] (χ² = 0.495, P = 0.482). In addition, there was no age-specific prevalence of G. lamblia infections among the participants (χ² = 1.534, P = 0.675). Multivariate logistic regression analysis identified use of septic tanks [odds ratio (OR) = 3.336, 95% CI: (1.201, 9.267)], daily use of well water [OR = 3.042, 95% CI: (1.093, 8.465)] and raising livestock [OR = 3.740, 95% CI: (1.154, 12.121)] as risk factors of G. lamblia infections among colorectal cancer patients, and the prevalence of abdominal pain was significantly greater in colorectal cancer patients with G. lamblia infections than in those without infections (P = 0.017). Among the 25 patients with G. lamblia infections, assemblage A was characterized in 24 (96.0%) cases and assemblage B in one case (4.0%).

CONCLUSIONS

The prevalence of G. lamblia is high among colorectal cancer patients in Henan Province, and assemblage A is the dominant genotype of G. lamblia. Use of septic tanks, daily use of well water and raising livestock are risk factors of G. lamblia infections among patients with colorectal cancer.

[A study on the correlation between occupational radiation exposure and risk of chronic metoblis disease]

Objective: To study the correlation between occupational radiation exposure and chronic metabolic diseases. Methods: The status of chronic metabolic diseases of medical workers were compared in 5 hospitals in Hangzhou. As representatives of chronic metabolic diseases, diabetes and metabolic syndrome (MS) were compared in association with duration of radiation exposure. Results: Long-term ionizing radiation (IR) exposure was led to increased blood pressure, fasting blood glucose (FBG) , dyslipidemia, gallbladder disease, and MS. The years of radiation exposure was associated with lens opacity, gallstone and MS in men and gallbladder polyps in women. Radiation working more than 10 years is one of the independent risk factors for increased FBG and MS. Moreover, the risk of FBG increase in the group of radiation working more than 10 years was 3.052 times of that the non-exposed group, and the risk of MS occurrence was 4.132 times that of the non-exposed group. Conclusion: Long-term exposure to IR increases the risk of chronic metabolic diseases.

A novel dentin bonding scheme based on extrafibrillar demineralization combined with covalent adhesion using a dry-bonding technique

Dentin bonding is a dynamic process that involves the penetration of adhesive resin monomers into the extrafibrillar and intrafibrillar demineralized collagen matrix using a wet-bonding technique. However, adhesive resin monomers lack the capacity to infiltrate the intrafibrillar space, and the excess water that is introduced by the wet-bonding technique remains at the bonding interface. This imperfectly bonded interface is inclined to hydrolytic degradation, severely jeopardizing the longevity of bonded clinical restorations. The present study introduces a dentin bonding scheme based on a dry-bonding technique, combined with the use of extrafibrillar demineralization and a collagen-reactive monomer (CRM)-based adhesive (CBA). Selective extrafibrillar demineralization was achieved using 1-wt% high-molecular weight (MW) carboxymethyl chitosan (CMCS) within a clinically acceptable timeframe to create a less aggressive bonding substance for dentin bonding due to its selectively extrafibrillar demineralization capacity. CMCS demineralization decreased the activation of in situ collagenase, improved the shrinking resistance of demineralized collagen, and thus provided stronger and more durable bonding than traditional phosphoric acid etching. The new dentin bonding scheme that contained CMCS and CBA and used a dry-bonding technique achieved an encouraging dentin bonding strength and durability with low technical sensitivity. This bonding scheme can be used to improve the stability of the resin-dentin interface and foster the longevity of bonded clinical restorations.

Synthesis and receptor dependent 4D-QSAR studies of 4,5-dihydro-1,3,4-oxadiazole derivatives targeting cannabinoid receptor

Cannabinoid receptor has been shown to be overexpressed in various types of cancers, especially non-small cell lung cancer. As a result, it could be used as novel target for anticancer treatments. Because receptor-dependent 4D-QSAR generates conformational ensemble profiles of compounds by molecular dynamics simulations at the binding site of the enzyme, this work describes the synthesis, biological activity evaluation and 4D-QSAR studies of 4,5-dihydro-1,3,4-oxadiazole derivatives targeting cannabinoid receptor. Compared with WIN55,212-2, compound 5 f showed the best antiproliferative activity. The receptor-dependent 4D-QSAR model was generated by multiple linear regression method using QSARINS. Leave-n-out cross-validation and chemical applicability domain were performed to analyse the independent test set and to verify the robustness of the model. The best 4D-QSAR model showed the following statistics: r² = 0.8487, Q²_LOO = 0.7667, Q²_LNO = 0.7524, and r²_Pred = 0.8358.

The antibacterial effect and physical performance of pit and fissure sealants based on an antibacterial core-shell nanocomposite

The application of pit and fissure sealants is a well-established method to prevent and treat early childhood caries. Resin-based sealants with antibacterial properties provide additional benefits for caries prevention in a cariogenic oral environment. The objective of this study was to evaluate the effect of an antibacterial core-shell AgBr/cationic polymer nanocomposite (AgBr/BHPVP) on the properties of a resin-based pit and fissure sealant. A commercialized pit and fissure sealant without fluoride, Concise (3M, ESPE, USA), was used as the parent material and negative control. Experimental antibacterial sealants were formulated by the addition of AgBr/BHPVP nanoparticles at mass fractions of 0.5, 1.0, and 1.5 wt% to the parent material. A fluoride-releasing sealant, Clinpro (3M, ESPE), was used as the positive control. Bacterial colony-forming unit (CFU) counts, metabolic activity tests, field emission-scanning electron microscopy (FE-SEM), and confocal laser scanning microscopy (CLSM) observations were used to evaluate the antibacterial properties of AgBr/BHPVP-modified sealants against Streptococcus mutans before and after five months of aging. The Vickers microhardness, degree of conversion, and microleakage level of the sealants were also investigated. According to the results of CFU counts and metabolic tests, sealants containing AgBr/BHPVP showed better contact-killing bactericidal activity against S. mutans than the two commercial sealants, irrespective of aging conditions (both P < 0.05). The AgBr/BHPVP-modified sealants also showed a significant inhibitory effect on the planktonic S. mutans around the cured sealant surfaces. In addition, the Vickers microhardness, degree of conversion, and microleakage level of the parent material were not damaged by modification with AgBr/BHPVP (P > 0.05). AgBr/BHPVP-modified pit and fissure sealant with a dual bactericidal mechanism is a promising option for the prevention of pit and fissure caries.

[Prevalence and risk factors of Blastocystis hominis infections among AIDS patients in Nanchang City]

OBJECTIVE

To investigate the prevalence and risk factors of Blastocystis hominis infections among AIDS patients in Nanchang City.

METHODS

A cross-sectional questionnaire survey was conducted among AIDS patients in Nanchang City during the period between May and September, 2016. B. hominis infection was detected in patients'stool samples using a PCR assay, and the CD4⁺ T cell count was measured in subjects'blood samples. In addition, the risk factors of B. hominis infection in AIDS patients were identified using univariate and multivariate logistic regression analyses.

RESULTS

A survey was conducted in Nanchang City from May to September 2016. A total of 505 AIDS patients were investigated, and the prevalence of B. hominis infection was 4.16%. Univariate analysis revealed that B. hominis infection correlated with the occupation (χ² = 8.595, P = 0.049), education level (χ² = 14.494, P = 0.001), type of daily drinking water (χ² = 10.750, P = 0.020), root of HIV infections (χ² = 8.755, P = 0.026) and receiving anti-HIV therapy (χ² = 23.083, P = 0.001) among AIDS patients, and multivariate logistic regression analysis identified daily direct drinking of tap water as a risk factor of B. hominis infections [odds ratio (OR) = 7.988, 95% confidential interval (CI): (1.160, 55.004)] and anti-HIV therapy as a protective factor of B. hominis infection [OR = 0.183, 95% CI: (0.049, 0.685)].

CONCLUSIONS

The prevalence of B. hominis is 4.16% among AIDS patients in Nanchang City. Daily direct drinking of tap water is a risk factor, and anti-HIV therapy is a protective factor of B. hominis infection among AIDS patients living in Nanchang City.

[Progress of researches on Blastocystis infections in humans and animals in China]

Blastocystis is a unicellular, anaerobic, intestinal protozoan that infects humans and a variety of animals, which is widely prevalent across the world. Blastocystis infections have been detected in healthy populations, children, students, outpatients and inpatients, as well as diarrhea patients in China. High prevalence of Blastocystis infections has been reported in immunocompromised patients, and relatively high prevalence was seen in individuals living in Guangxi and Yunnan regions. Based on the small subunit ribosomal RNA (SSU rRNA) gene sequence, a total of 17 subtypes (ST1 to ST17) of Blastocystis have been characterized until now, among which ST1 to ST9 and ST12 infect humans and animals, and ST10 to ST17 only infect animals. In China, ST1 to ST3 are predominant human Blastocystis subtypes, and ST1/ST3, ST1/ST2 and ST2/ST3 mixed infections have been also identified. This review mainly describes the epidemiology and genotypes of Blastocystis in humans and animals in China.

[Study of bone mineral density and serum bone turnover markers in newly diagnosed systemic lupus erythematosus patients]

OBJECTIVE

To investigate the changes of bone mineral density (BMD) and serum bone turnover factor in newly diagnosed systemic lupus erythematous (SLE) patients.

METHODS

Eighty newly diagnosed SLE patients and 80 age and gender matched healthy controls were enrolled. None of the SLE patients had ever received glucocorticoid, immunosuppressive agents or vitamin D. BMD was measured at radius,lumbar spine and hip by dual X ray absorptiometry (DXA). Bone turnover markers including serum levels of tartrate-resistant acid phosphatase 5b (TRAP5b),bone alkaline phosphatase (BAP) and 25-hydroxy vitamin D3 (25-OH-VD3) were measured by enzyme-linked immunosorbent assay (ELISA). Logistic regression was employed to analyze the risk factors associated with decreased BMD.

RESULTS

Mean age of the SLE patients was (32.8±12.4) years, and 85% were female, none of whom were post-menopausal. BMD was significantly reduced in all the measured sites, compared with the healthy controls. Sixteen (20%) of the patients were osteopenic in at least one site measured locations. The serum levels of 25-OH-VD3 were markedly reduced in the newly diagnosed SLE patients than those of the normal controls [(46.1+12.3) nmol/L vs. (25.4+11.2) nmol/L, P<0.001)]. The serum levels of 25-OH-VD3 in the SLE patients with nephritis were much lower than those without nephritis (P=0.04). A significant negative correlation was demonstrated between the serum concentration of 25-OH-VD3 and the disease activity scores as measured by SLE disease activity index (SLEDAI) (r=-0.3,P=0.001). The serum TRAP5b concentration was positively correlated with SLEDAI (r=0.435,P=0.003). Age (P=0.058) and SLEDAI (P=0.085) were probably associated with decreased BMD in Logistic regression analysis.

CONCLUSION

The study showed reduced BMD in untreated SLE patients. The role of chronic inflammation was of probable importance in bone metabolism.

[Application and efficacy of endotracheal tube of drug injection for postoperative patients]

Objective: To evaluate the efficacy of endotracheal tube for drug injection in postoperative ICU patients. Methods: A total of 60 ICU patients who were given mechanical ventilation after surgical treatment were enrolled in this study from January 2015 to August 2016 at our hospital. All the patients were divided into the observation group (30 cases) and the control group (30 cases). In the observation group, the patients were treated with the endotracheal tube for surface anesthesia by injecting 2% lidocaine into the trachea, and patients in the control group were treated with saline instead of lidocaine. Patients' tolerance to endotracheal tube, cardiovascular system adverse reactions, the frequency and dosage of sedative and analgesic drug within 12 h mechanical ventilation post operation were analyzed and compared between the two groups. Results: The occurrence rate of cough, hypertension and tachycardia in the observation group were(0.6±0.3), (0.8±0.3)and(1.3±0.6), respectively, which were significantly lower than the control group (5.9±2.1), (6.0±1.9)and(4.9±1.8), the differences were statistically significant (P<0.05). In addition, the frequency of sedative drug was (0.8±0.3), with a dosage of midazolam(1.2±0.3)mg. While in the control group, the frequency of sedative drugs was (5.1±1.9), with a dosage of midazolam (9.9±3.2) mg. The frequency and dosage of sedative drug administration in the observation group were significantly lower than those in the control group, the difference was significant difference (P<0.05). Conclusions: The use of endotracheal tube for drug injection can improve the tolerance of ICU patients to endotracheal tube, reduce the dosage of sedative drugs, and reduce the adverse cardiovascular reactions.

[Influence of history of oral bisphosphonates on the incidence rate of fever after intravenous injection of zoledronic acid in patients with osteoporosis]

OBJECTIVE

To investigate the prevalence of fever after intravenous injection of for the first time in osteoporotic patients who have or haven't taken bisphosphonates orally.

METHODS

Bone mineral density measurement was conducted of the osteoporotic patients using dual-energy X-ray absorptiometry method, and according to the WHO diagnostic criteria for osteoporosis, the patient whose T score was less than -2.5 was defined as osteoporosis. The data of 113 osteoporotic patients who received intravenous injection of zoledronic acid in our hospital for the first time were used for analysis. Among them, 35 who had the history of oral bisphosphonates were defined as group A, and 78 who didn't have the history of oral bisphosphonates were defined as group B (control group). Moreover, we also compared the prevalences of fever between the patients. Pearson chi-square test was used to investigate the association between oral bisphosphonates therapy and prevalence of fever, and binary logistic regression was used to analyze the impact factors of fever after intravenous injection of zoledronic acid.

RESULTS

Among the 35 patients who had the history of oral bisphosphonates, nobody had high fever, and 2 patients had low or moderate degree of fever (5.71%). Among the 78 patients who didn't have the history of oral bisphosphonates, 33 patients had fever (42.3%), 15 with low fever, and 14 with moderate degree of fever, and 4 with high fever. Pearson chi-square test showed that the prevalence of fever between group A and group B had significant difference, and that differences of prevalence of fever between the outpatients and the inpatients was not statistically significant. Binary Logistic regression analysis showed that oral bisphosphonates medication history was a protective factor of fever, and with the increasing of previous oral bisphosphonates for one month, there was a reduction of fever for 23.1%.

CONCLUSION

Patients who have the history of oral nitrogenous bisphosphonates alendronate have a significant reduction in prevalence of fever after intravenous injection of zoledronic acid for the first time. That is, oral nitrogenous bisphosphonates alendronate history is a protective factor of fever for patients with intravenous injection of zoledronic acid for the first time.

[Influence of history of oral bisphosphonates on the incidence rate of fever after intravenous injection of zoledronic acid in patients with osteoporosis]

OBJECTIVE

To investigate the prevalence of fever after intravenous injection of for the first time in osteoporotic patients who have or haven't taken bisphosphonates orally.

METHODS

Bone mineral density measurement was conducted of the osteoporotic patients using dual-energy X-ray absorptiometry method, and according to the WHO diagnostic criteria for osteoporosis, the patient whose T score was less than -2.5 was defined as osteoporosis. The data of 113 osteoporotic patients who received intravenous injection of zoledronic acid in our hospital for the first time were used for analysis. Among them, 35 who had the history of oral bisphosphonates were defined as group A, and 78 who didn't have the history of oral bisphosphonates were defined as group B (control group). Moreover, we also compared the prevalences of fever between the patients. Pearson chi-square test was used to investigate the association between oral bisphosphonates therapy and prevalence of fever, and binary logistic regression was used to analyze the impact factors of fever after intravenous injection of zoledronic acid.

RESULTS

Among the 35 patients who had the history of oral bisphosphonates, nobody had high fever, and 2 patients had low or moderate degree of fever (5.71%). Among the 78 patients who didn't have the history of oral bisphosphonates, 33 patients had fever (42.3%), 15 with low fever, and 14 with moderate degree of fever, and 4 with high fever. Pearson chi-square test showed that the prevalence of fever between group A and group B had significant difference, and that differences of prevalence of fever between the outpatients and the inpatients was not statistically significant. Binary Logistic regression analysis showed that oral bisphosphonates medication history was a protective factor of fever, and with the increasing of previous oral bisphosphonates for one month, there was a reduction of fever for 23.1%.

CONCLUSION

Patients who have the history of oral nitrogenous bisphosphonates alendronate have a significant reduction in prevalence of fever after intravenous injection of zoledronic acid for the first time. That is, oral nitrogenous bisphosphonates alendronate history is a protective factor of fever for patients with intravenous injection of zoledronic acid for the first time.

Alendronate sodium/vitamin D3 combination tablet versus calcitriol for osteoporosis in Chinese postmenopausal women: a 6-month, randomized, open-label, active-comparator-controlled study with a 6-month extension

This study compares efficacy of ALN/D5600 versus that of calcitriol in osteoporotic Chinese postmenopausal women. ALN/D5600 produced greater bone mineral density (BMD) increases, greater bone turnover marker decreases, and less vitamin D insufficiency. This study provided detailed clinical information regarding ALN/D5600 treatment versus calcitriol 0.25 μg/day. The study did not evaluate fracture risk.

INTRODUCTION

The aim of this study is to investigate efficacy of alendronate 70 mg/vitamin D3 5600 IU combination tablets (ALN/D5600) versus calcitriol in osteoporotic Chinese postmenopausal women.

METHODS

This study is a 6-month, randomized, open-label, active-comparator study with 6-month extension (clinicaltrials.gov number NCT01350934) in postmenopausal women aged >55 years with osteoporosis (low bone mineral density (BMD) with/without prior fragility fracture). Patients were randomized to ALN/D5600 once weekly or calcitriol 0.25 μg daily. The primary efficacy end point of the base study was percent change from baseline in lumbar spine BMD (month 6). Hypercalcemia and hypercalciuria were safety events of special interest.

RESULTS

A total of 219 patients (ALN/D5600 n = 111, calcitriol n = 108) were randomized. Baseline characteristics were similar, 30.3 % baseline 25-hydroxyvitamin D (25(OH)D) ≤15 ng/mL. At months 6 and 12, changes in lumbar spine BMD from baseline were 3.5 versus 1.6 % and 5.2 versus 2.3 % for ALN/D5600 versus calcitriol (between-group differences p < 0.001), respectively. Between-group differences for ALN/D5600 versus calcitriol were significant (p < 0.001) at months 6 and 12 for change from baseline in procollagen type 1 N-terminal propeptide (-59.1 versus -16.8 %, -68.1 versus -17.0 %) and serum C-telopeptides (-79.2 versus -27.2 %, -76.2 versus -24.2 %). Drug-related adverse events (AEs) and discontinuations due to drug-related AEs occurred in 15 (14.0 %) versus 8 (7.4 %) patients and 3 (2.8 %) versus 0 patients in the ALN/D5600 and calcitriol group, respectively. Hypercalciuria 12-month incidence (24-h urine Ca >300 mg) was 8.4 (ALN/D5600) versus 13.9 % (calcitriol) (p > 0.05). One patient (calcitriol) had hypercalcemia.

CONCLUSIONS

ALN/D5600 produced greater increases in lumbar spine BMD and greater decreases in bone turnover markers versus calcitriol in osteoporotic Chinese women. It is not known whether the greater increase in BMD results in fewer fractures. ALN/D5600 was generally well tolerated in Chinese patients.

Long-term follow-up of a phase III study comparing radiotherapy with or without weekly oxaliplatin for locoregionally advanced nasopharyngeal carcinoma

BACKGROUND

Previous results from our trial showed that adding oxaliplatin to radiotherapy (RT) increased survival in patients with locoregionally advanced nasopharyngeal carcinoma (NPC) at 2 years. Here, we present the data of long-term efficacy and late toxic effects.

PATIENTS AND METHODS

Between January 2001 and January 2003, 115 Patients with nonkeratinizing/undifferentiated locoregionally advanced NPC were randomly to receive either RT alone (n = 56) or plus concurrent oxaliplatin 70 mg/m(2) weekly for six cycles (n = 59).

RESULTS

After a median follow-up of 114 months (range 18-139 months), the 5-year overall survival (OS) and metastasis-free survival (MFS) rates in the concurrent chemoradiotherapy (CCRT) group were significantly higher than those observed in the RT-alone group (OS, 73.2% versus 60.2%, P = 0.028; MFS, 74.7% versus 63.0%, P = 0.027). However, CCRT did not improve locoregional failure-free survival significantly. Subgroup analyses showed that the superiorities of CCRT mainly existed in the T3-4N0-1 stage subgroup (OS: HR = 0.394, P = 0.034). The grade 3/4 late toxic effects were similar in the two groups.

CONCLUSION(S)

The long-term follow-up data confirms the role of CCRT as a treatment of locoregionally advanced NPC. Oxaliplatin can be considered as an alternative optional therapeutic regimen for these patients due to its high efficiency and low toxic effect.

Phase II study of sorafenib in combination with cisplatin and 5-fluorouracil to treat recurrent or metastatic nasopharyngeal carcinoma

BACKGROUND

We aimed to investigate the efficacy and tolerability of sorafenib combined with cisplatin and 5-fluorouracil (5-FU) in patients with recurrent or metastatic nasopharyngeal carcinoma (NPC).

PATIENTS AND METHODS

It was a Simon two-stage designed trial. Chemotherapy-naive patients with recurrent or metastatic disease were enrolled. The regimen was sorafenib 400 mg orally b.i.d., cisplatin 80 mg/m(2) i.v. day 1, and 5-FU 1000 mg/m(2)/day CIV for 4 days, repeated every 21 days. After a maximum of six cycles of chemotherapy, patients received maintenance of sorafenib.

RESULTS

In total, 54 patients were enrolled. The objective response rate reached 77.8%, including 1 complete response and 41 partial responses. The median progression-free survival was 7.2 months (95% CI 6.8-8.4 months), and the median overall survival was 11.8 months (95% CI 10.6-18.7 months). Major toxic effects included hand-foot skin reaction, myelosuppression, and gastrointestinal (GI) reaction. The incidence of hemorrhage was 22.2%, and one patient with liver metastases died of GI bleeding. Contrast-enhanced ultrasonography was carried out in a subset of patients with liver metastases.

CONCLUSION

Combination of sorafenib, cisplatin (80 mg/m(2)) and 5-FU (3000 mg/m(2)) was tolerable and feasible in recurrent or metastatic NPC. Further randomized trials to compare sorafenib plus cisplatin and 5-FU with standard dose of cisplatin plus 5-FU in NPC are warranted.

Inhibition of reverse transcriptase activity of hepatitis B virus polymerase by β-l-D4A-TP

β-L-enantiomer of 2',3'-didehydro-2',3'-dideoxyadenosine-5'-triphosphate (β-L-D4A-TP) has previously been proven to inhibit the replication of viral DNA in the Hep G2 2.2.15 cells and in transgenic mouse harboring 1.3-fold-overlength genome of Hepatitis B virus (HBV). To study the inhibition mechanism of the nucleoside analog β-L-D4A-TP, a polymerase reaction in vitro with the recombinant HBV nucleocapsids was conducted to determine the exact mode of inhibition of the HBV replication by β-L-D4A-TP. The HBV viral DNA and viral DNA-polymerase complex formed in the polymerase reaction were assayed. The results of this study showed that β-L-D4A-TP inhibited the replication of HBV DNA by inactivating the reverse transcriptase (RT) activity in a concentration-dependent manner. The kinetics of β-L-D4A-TP inhibition of the RT activity was the result of an apparent competitive inhibition with dATP.

RETRACTED: Isolation, characterization and expression of a gene from Brassica napus encoding a LIM-domain protein

This article has been retracted consistent with Elsevier Policy on Article Withdrawal. Please see http://www.elsevier.com/locate/withdrawalpolicy The Publisher apologizes for any inconvenience this may cause.

Microencapsulated nerve growth factor-expressing NIH3T3 cells-incorporated tissue engineering skin: a preliminary study

INTRODUCTION

In order to find a suitable carrier to deliver the product of gene transfection to improve the performance of bioengineered dermis, we used microencapsulation and gene transfection technology together for the first time and found that it was feasible.

METHODS

We used a recombinant nerve growth factor (pcDNA3.1+/NGF) to modify NIH3T3 cells genetically. Control of NIH3T3-NGF cells were encapsulated within microspheres composed of alginate-poly-L-lysine-alginate and cultivated in-vitro. The concentration of NGF released from the microencapsulated NIH3T3-NGF cells was confirmed using ELISA assay. We co-cultivated microencapsulated NIH3T3-NGF cells, NIH3T3 cells (control) with human keratinocytes and fibroblasts, and tested the percentage of cycle of these cells. The alkaline hydrolysis method was used to analyse the content of hydroxyproline (Hyp). Immunohistochemistry method was used to calculate the transformation efficiency from fibroblasts to myofibroblasts.

RESULTS

The concentration of NGF released from the microencapsulated NIH3T3-NGF cells lasted about six weeks in the supernatant of bioengineered dermis in-vitro. The proliferation of keratinocytes, as well as the concentration of Hyp in supernatant of fibroblasts, were promoted about three times. Transformation efficiency from fibroblasts to myofibroblasts was increased approximately two-fold because of the bio-effects of NGF. Two kinds of microencapsulations were seeded into collagen which contained human fibroblasts to form bioengineered skin. Microencapsulated NIH3T3-NGF cells formed a thicker dermis. The concentration of Hyp in the bioengineered skin which indicated the level of collagen synthesis was increased due to existing NGF.

CONCLUSION

Microencapsulated NIH3T3-NGF cells can be used to enhance performance of bioengineered dermis and it also can be deduced that other cytokines can be used to treat local wound areas.

A novel HLA-DRB1*15 allelic sequence isolated from the Han population of Guangdong, China

A novel DRB1*15 allele, DRB1*1516, has been identified in a Guangdong Han individual. Its sequence was confirmed by sequencing of polymerase chain reaction products and clones. This allele differed by one nucleotide from DRB1*150101 at position 220 (G-->A), resulting in an amino acid substitution from Gly to Arg at codon 45.

High efficiency gene transfer into mammalian kidney cells using baculovirus vectors

Gene delivery into kidney cells is essential to the development of gene therapy for nephropathy. This paper describes the use of baculovirus Autographa californica nucleopolyhedrovirus (AcMNPV) as a vector for gene delivery into several mammalian kidney cells. High-level expression of a reporter gene encoding for the green fluorescent protein (GFP) under a heterogonous promoter was observed in kidney cells from mouse, hamster, monkey, pig, and human. The level of transgene expression exhibited viral dose dependence and was enhanced by the addition of butyrate. Baculovirus transduction could also provided long-term target gene expression in kidney cell lines without cytotoxic effects. High efficiency transduction was also observed in primary mouse kidney cells. These results indicate that baculovirus can be used as a vector for kidney-directed gene transfer.

High-rate anaerobic hydrolysis and acidogenesis of sewage sludge in a modified upflow reactor

Continuous experiments were conducted to study the hydrolysis and acidogenesis of sewage sludge in an upflow reactor with an agitator and a gas-liquid-solid separator. Results of this study showed that 34-78% of volatile suspended solids (VSS) in sewage sludge was hydrolyzed at pH in the range 4.0-6.5, 35 degrees C and 4-24 hours of hydraulic retention time (HRT). About 31-65% of carbohydrate in sewage sludge, 20-45% of protein and 14-24% of lipid were acidified in this reactor. Hydrogen production was favored in lower pH and HRT, whereas methane production was encouraged at higher pH and HRT. Acetate, propionate, butyrate, and i-butyrate were the main aqueous acidogenic products. The distribution of these compounds in the effluent was more sensitive to pH, but was less sensitive to HRT. The maximu specific COD solubilization rate and specific volatile fatty acids production rate were 126 mg-COD/g-VSS x d and 102 mg-VFAIg-VSS x d, respectively. Compared with a CSTR, this modified upflow reactor was shown to be a more promising biosystem for the hydrolysis and acidogenesis of sewage sludge.

Comparative analysis of the complete genome sequences of Helicoverpa zea and Helicoverpa armigera single-nucleocapsid nucleopolyhedroviruses

The complete nucleotide sequence of Helicoverpa zea single-nucleocapsid nucleopolyhedrovirus (HzSNPV) has been determined (130869 bp) and compared to the nucleotide sequence of Helicoverpa armigera (Ha) SNPV. These two genomes are very similar in their nucleotide (97% identity) and amino acid (99% identity) sequences. The coding regions are much more conserved than the non-coding regions. In HzSNPV/HaSNPV, the 63 open reading frames (ORFs) present in all baculoviruses sequenced so far are much more conserved than other ORFs. HzSNPV has four additional small ORFs compared with HaSNPV, one of these (Hz42) being in a correct transcriptional context. The major differences between HzSNPV and HaSNPV are found in the sequence and organization of the homologous regions (hrs) and the baculovirus repeat ORFs (bro genes). The sequence identity between the HzSNPV and HaSNPV hrs ranges from 90% (hr1) to almost 100% (hr5) and the hrs differ in the presence/absence of one or more type A and/or B repeats. The three HzSNPV bro genes differ significantly from those in HaSNPV and may have been acquired independently in the ancestral past. The sequence data suggest strongly that HzSNPV and HaSNPV are variants of the same virus species, a conclusion that is supported by the physical and biological data.

[Histochemical localization and quantitative analysis of anthraquinones in rhizome of Polygonum cuspidatum]

Anthraquinones were histochemically locayed and content were determined in rhizome of Polygonum cuspidatum. Anthraquinones were located in the parenchyma cells of rhizome, including vascular ray, part of parenchyma cell in phloem, cortex and pith. Phelloderm and ray initial also accumulated a small amount anthraquinones. The content of total anthraquinones was highest in pith that consisted of parenchyma cells, and higher in bark (including phloem, cortex and periderm) than in xylem. The content of total anthraquinones was highest in three-year-old rhizome, and higher in biennial rhizome than in annual rhizome. It suggests that correlation exist between accumulation of anthraquinones and the growth age of rhizome.

[Determination and purification of beta-carotene in Spirulina maximum]

There are several kinds of nutritious materials in Spirulina maximum, and beta-carotene is one of the most important materials. Because beta-carotene is of low polarity, for purification it was extracted with the mixture of acetone and methanol in the ratio of 7:2 (V/V), then saponified, and extracted with petroleum ether, purified with column packed with neutral Al2O3. Its content was determined by reversed-phase HPLC. This method is accurate and the results are reproducible. The average recovery was 96.8%.

[Star figure in medical monitoring during lower body negative pressure test]

Objective. To find a real-time, quick and audio-visual method to evaluate the subject's physiological function condition and possible development. Method. Star figure technique was adopted to analyse multiple physiological indices during lower body negative pressure test (LBNP). Based on the character and stability of the stars figure, the steadiness of the subjects physiological function can be judged. Result. Physiological function can be accurately assessed only when the model of stress response of an individual is formed. Conclusion. The changes of star figure can indicate the possible development of the physiological function stage.

[Study of formula for calculating body surface areas of the Chinese adults]

The body surface area of 100 Chinese adults (50 for each sex) was measured with the paper cast method and compared to the results estimated by the Stevenson's "height-weight-surface" formula. Our results shows that Stevenson's formula is no longer suitable for the Chinese. Our formulae for Chinese are as follows: SI=0.0061 x H + 0.0124 x W - 0.0099 (for both sexes), SII=0.0057 x H + 0.0121 - W + 0.0882 (for male), SIII=0.0073 H + 0.0127 x W - 0.2106 (for female) H: body height, W: body weight, S: body surface area

[Over-expression of a polyketide synthase (PKS) module of a giant polyene antibiotic gene cluster in E. coli by double induction]

A 2,671 bp DNA carrying a type I PKS module with KS and AT domains from Streptomyces sp. FR-008 was cloned in-frame into the BamHI site immediately downstream of the PT7 promoter of the E. coli expression vector pET-15b, no considerable expression under IPTG induction was detected. The same PKS gene cloned downstream of the tandem PRPL promoters of pBV220 also yielded no over-expression under 42 degrees C induction. This gene was, however, over-expressed when it was cloned downstream of the tandem PRPT7 or PRPLPT7 promoters. In the case of the tandem PRPLPT7 promoters, the over-expression was dependent on the 42 degrees C plus IPTG double induction. While in the case of the tandem PRPT7 promoters, over-expression could be achieved when the gene was induced by IPTG or 42 degrees C individually or by IPTG and 42 degrees C double induction. Based on these experiences an expression vector pHZ330 containing the tandem PRPT7 promoters was constructed. In addition, the PKS protein expressed in E. coli was injected into rabbits to generate PKS-specific antibodies. Western blotting experiment indicated that these antibodies were PKS-specific which could be used either for the study of the PKS gene cluster or for the detection of the heterologous expression of Streptomyces sp. FR-008 PKS genes.

Distinct gene arrangement in the Buzura suppressaria single-nucleocapsid nucleopolyhedrovirus genome

The genome organization of the Buzura suppressaria single-nucleocapsid nucleopolyhedrovirus (BusuNPV) was largely elucidated and compared to those of other baculoviruses. A detailed physical map was constructed for the restriction enzymes BamHI, BglI, BglII, EcoRI, HindIII, KpnI, PstI, XbaI and XhoI. The 120.9 kbp viral genome was cloned as restriction fragments into a plasmid library from which about 43.5 kbp of dispersed sequence information was generated. Fifty-two putative open reading frames homologous to those of other baculoviruses were identified and their location in the genome of BusuNPV was determined. Although the gene content of BusuNPV is similar to that of Autographa californica multiple-nucleocapsid nucleopolyhedrovirus, Bombyx mori nucleopolyhedrovirus and Orgyia pseudotsugata multiple-nucleocapsid nucleopolyhedrovirus, the gene order is, however, significantly different from that observed in the other viruses, which have a high degree of collinearity. A new approach (GeneParityPlot) was developed to represent the differences in gene order among baculoviruses when limited sequence information is available and to take advantage of the high degree of gene conservation. The data obtained show that BusuNPV is a distinct baculovirus species and the analyses suggest that gene distribution along baculovirus genomes may be used as a phylogenetic marker.

Prevalence of hepatitis B and C infection markers among adult women in urban and rural areas in Shaanxi Province, China

In an attempt to investigate possible urban-rural difference in prevalence of hepatitis B and C virus (HBV and HCV, respectively) infection in continental China, triplet surveys on HBV and HCV infection markers (ie, HBsAg, anti-HBs, anti-HBc, and anti-HCV) and serum enzyme levels (AST, ALT and gamma-GTP) were conducted in 1997 on groups of apparently healthy adult women (49 to 50 subjects per group); one group (the City group) was in Xian, the provincial capital of Shaanxi Province, and two others (the Village A group and the Village B group) were in farming villages in the Province some 200 and 25 km away from Xian, respectively. Comparison among the three groups showed that there was no urban-rural difference in prevalence of HBV and HCV infection positive (HBV+ and HCV+) cases and that the overall prevalence of HBV+ and HCV+ cases was 70% and 3%, respectively. HBsAg+ prevalence was however higher in the villages (8% when the two villages were combined) than in the city (2%). HBV infection was not associated in general with apparent increase in emission enzyme levels in the serum, whereas HCV infection might be associated with an increase in ALT, AST and gamma-GTP. The present observation in combination with other previously published results suggests that urban-rural difference will not be remarkable in HBV and HCV infection prevalence in Continental China and that the public health problem is more serious with HBV infection and quite less so with HCV infection.

Genetic organization of the HindIII-I region of the single-nucleocapsid nucleopolyhedrovirus of Buzura suppressaria

In order to investigate the genomic organization of the single-nucleocapsid nucleopolyhedrovirus (SNPV) of Buzura suppressaria (BusuNPV), the HindIII-I fragment located at map units (mu) 26.6-29.4 of the viral genome was sequenced. The fragment contained two partial and three complete open reading frames (ORFs) representing the 3' end of a polyhedron envelope protein gene (pep), a homologue of the AcMNPV ORF117, a conotoxin-like protein gene (ctl), an inhibitor of apoptosis gene (iap) and a superoxide dismutase gene (sod), respectively. These five genes were identified for the first time in a SNPV. Sequence analysis further revealed that these ORFs have the same conserved motifs and gene structure as those observed in their homologues from other baculoviruses. Between ctl and iap, an intergenic region of about 700 basepairs with structure similar to non-hr origins of DNA replication was observed. The genomic arrangement of the ORFs in the BusuNPV HindIII-I fragment is very different from the arrangement of their homologues in the genome of Autographa californica multiple nucleocapsid (M) NPV and other baculoviruses to date. Our data suggest that on the basis of gene arrangement, BusuNPV belongs to a distinct taxon within the Baculoviridae family, corroborating our previous conclusions derived from phylogeny analysis of several BusuNPV genes.

Baculoviruses contain a gene for the large subunit of ribonucleotide reductase

In the genomes of two baculoviruses, Spodoptera exigua and S. littoralis multicapsid nucleopolyhedroviruses (SeMNPV and SpliMNPV, respectively), an open reading frame (ORF) encoding the large subunit of ribonucleotide reductase (RR1) was identified. The predicted amino acid sequences of SeMNPV and SpliMNPV RR1 showed high homology to RR1 proteins from eukaryotes (ca. 70% and 80% similarity, respectively). The amino acid residues thought to be involved in catalytic function were conserved in the baculoviral RR1 ORFs. The RR1 ORFs in SeMNPV and SpliMNPV were located in different genomic positions. In SeMNPV, the RR1 ORF was located upstream of the polyhedrin gene, in an anti-genomic orientation. In SpliMNPV, the RR1 ORF preceded the p74 gene. By searching databanks, sequences homologous to the N terminus of RR1 were also detected upstream of the polyhedrin gene of three other baculoviruses, Mamestra brassicae multicapsid NPV, Panolis flammea multicapsid NPV and Orgyia pseudotsugata single nucleocapsid NPV. The baculovirus type species, Autographica californica multicapsid NPV, however, does not encode RR. A 2.7 kb transcript could be detected throughout infection with SeMNPV, classifying SeMNPV rr1 as an early gene. Primer extension analysis revealed several early and late start sites. None of the major start sites showed similarity to previously characterized baculoviral transcriptional start motifs. Phylogenetic analysis of prokaryotic, eukaryotic and viral RR1 proteins suggested that SeMNPV and SpliMNPV acquired the gene for RR1 from a eukaryotic source, but independently from each other.

Characterization of the ecdysteroid UDP-glucosyltransferase gene of a single nucleocapsid nucleopolyhedrovirus of Buzura suppressaria

A putative ecdysteroid UDP-glucosyltransferase (egt) gene was identified in the single nucleocapsid nucleopolyhedrovirus of Buzura suppressaria (BusuNPV). This is the first egt gene to be characterized in a SNPV, suggesting that egt genes are prevalent in nucleopolyhedroviruses and possibly in all baculoviruses. The open reading frame (ORF) of the gene is 1539 nucleotides (nt) long, encoding a putative protein (EGT) of 513 amino acids (aa) with a M of 58922. The 5' noncoding region contains three possible TATA boxes. A polyadenylation signal, AATAAA, was found downstream of the translation stop codon. A putative signal peptide of 16 residues was present at the N-terminus of the EGT. The BusuNPV egt gene has a high degree of nucleotide and amino acid sequence homology to multiple nucleocapsid (M) NPV egt genes, the highest being to the Spodoptera exigua MNPV egt. A phylogenetic tree of eleven known EGTs was constructed using maximum parsimony analysis.

252Cf-plasma desorption mass spectrometry. II--A perspective of new directions

The 252Cf-PDMS method is a 'mature' technique, having survived 20 years of research, development and application. Recent advances in the application of the method have led to the use of the technique in clinical quantitation studies, the development of a microscopic method for measuring chemical homogeneity, in situ applications where serial modifications can be made and studied in a sequential fashion and the utilization of the primary fragmentation patterns to correlate with primary structure. Future directions in research, development and application will focus more attention on the chemistry of the 252Cf-PDMS process and the understanding and control of gas-phase reactions that occur in the ejection plume. Predictions are that the application of the in situ modification technique could lead to a new approach to pharmacokinetic studies as well as cell surface interactions where 252Cf-PDMS is effectively used to expand the capabilities of in vitro studies of biological processes.

Nucleotide sequence of the Buzura suppressaria single nucleocapsid nuclear polyhedrosis virus polyhedrin gene

A portion of the genome of the Buzura suppressaria (Lepidoptera) single nucleocapsid nuclear polyhedrosis virus (BsSNPV) containing the polyhedrin gene was sequenced. An open reading frame of 738 nucleotides encoded a protein of 246 amino acids and represented the polyhedrin gene. A conserved TAAG motif, associated with transcriptional start sites in other polyhedrin genes, was identified 51 nucleotides upstream of the BsSNPV polyhedrin gene. A putative polyadenylation signal, AATAAA, was found immediately downstream of the polypeptide termination codon. Comparison of the amino acid sequence of BsSNPV polyhedrin with other NPV polyhedrins and granulosis virus granulins showed that the BsSNPV polyhedrin was most closely related to the polyhedrin of Orgyia pseudotsugata (Lepidoptera) SNPV and most distantly related to the polyhedrin of Neodiprion sertifer (Hymenoptera) SNPV.

An efficacy trial of a mammalian cell-derived recombinant DNA hepatitis B vaccine in infants born to mothers positive for HBsAg, in Shanghai, China

We conducted a randomized, double-blind clinical trial of an experimental mammalian cell-derived DNA hepatitis B vaccine (Betagen, Connaught Laboratories Ltd, Toronto, Canada) to determine its efficacy in infants born to mothers who were carriers of hepatitis B surface antigen (HBsAg). Four groups of 55 infants received injections as follows: (1) a licensed plasma-derived vaccine (Lanzhou, Lanzhou Institute for Biological Products, Lanzhou, People's Republic of China), 20 micrograms; (2) Betagen, 20 micrograms; (3) Betagen, 20 micrograms+hepatitis B immune globulin (HBIG); and (4) Betagen, 10 micrograms+HBIG. Vaccine injections were given at birth and at 1 and 6 months and HBIG was given at birth. The vaccines were compared to a historical placebo control group. The efficacy of Betagen alone was 82.6% compared to 51.0% for the Lanzhou. Efficacy of Betagen increased with the concomitant use of HBIG. No infants who were HBsAg negative at birth and/or were born to hepatitis B e antigen (HBeAg) negative mothers became carriers. The rate of HBsAg in infants receiving Betagen alone, and born to mothers who were HBeAg positive, decreased from 60% at birth to 20% by the ninth month, compared to 62.5% and 50% (respectively) for Lanzhou. The percentage of infants with protective levels of antiHBs was significantly higher for Betagen alone than for Lanzhou, but the geometric mean titre of antiHBs for responders was not significantly different. We have shown that Betagen alone is highly efficacious in preventing the development of hepatitis B in infants born to mothers who are carriers of HBsAg and is also highly effective in reducing the carriage of HBsAg in infants who are HBsAg positive at birth and/or born to HBeAg positive mothers.

Mechanisms of joint neurotoxicity of n-hexane, methyl isobutyl ketone and O-ethyl O-4-nitrophenyl phenylphosphonothioate in hens

The joint neurotoxic action of simultaneous exposure to vapors of n-hexane and methyl iso-butyl ketone (MiBK) and dermally applied O-ethyl O-nitrophenyl phenylphosphonothioate (EPN) was studied in groups of five adult hens. Four groups of hens were concurrently exposed to a dermal 2.5 mg/kg of EPN, 1000 ppm of n-hexane and 100, 250, 500 or 1000 ppm of MiBK. Two groups were each exposed to binary mixtures of a dermal dose of 2.5 mg/kg of EPN and 250 ppm of MiBK or 1000 ppm of n-hexane. Another three groups of hens were exposed to either 250 ppm of MiBK, 1000 ppm of n-hexane or a dermal dose of 2.5 mg/kg of EPN. A Group of hens was kept untreated. All hens were terminated after 30 days of treatment. Hens exposed to MiBK or n-hexane vapor did not exhibit any toxicity signs. In contrast, hens treated with EPN alone or in combination with n-hexane and/or MiBK developed acute cholinergic and delayed neurotoxicity signs. Hen brain acetylcholinesterase and neurotoxic esterase activities were inhibited in hens treated concurrently with EPN, n-hexane and MiBK. MiBK alone or in combination with EPN and n-hexane induced liver microsomal cytochrome P-450 content and phenobarbital-inducible cytochrome P-450 enzyme activities. Microsomes from hens treated with EPN, n-hexane, MiBK or mixtures of EPN, n-hexane and MiBK significantly enhanced the biotransformation of EPN to the more neurotoxic oxidation metabolite O-ethyl O-4-nitrophenyl phenylphosphonate.(ABSTRACT TRUNCATED AT 250 WORDS)