Course of disease and related epidemiological parameters of COVID-19: a prospective study based on contact tracing cohort / 中华预防医学杂志

Objective: To analyze the course of disease and epidemiological parameters of COVID-19 and provide evidence for making prevention and control strategies. Methods: To display the distribution of course of disease of the infectors who had close contacts with COVID-19 cases from January 1 to March 15, 2020 in Guangdong Provincial, the models of Lognormal, Weibull and gamma distribution were applied. A descriptive analysis was conducted on the basic characteristics and epidemiological parameters of course of disease. Results: In total, 515 of 11 580 close contacts were infected, with an attack rate about 4.4%, including 449 confirmed cases and 66 asymptomatic cases. Lognormal distribution was fitting best for latent period, incubation period, pre-symptomatic infection period of confirmed cases and infection period of asymptomatic cases; Gamma distribution was fitting best for infectious period and clinical symptom period of confirmed cases; Weibull distribution was fitting best for latent period of asymptomatic cases. The latent period, incubation period, pre-symptomatic infection period, infectious period and clinical symptoms period of confirmed cases were 4.50 (95%CI:3.86-5.13) days, 5.12 (95%CI:4.63-5.62) days, 0.87 (95%CI:0.67-1.07) days, 11.89 (95%CI:9.81-13.98) days and 22.00 (95%CI:21.24-22.77) days, respectively. The latent period and infectious period of asymptomatic cases were 8.88 (95%CI:6.89-10.86) days and 6.18 (95%CI:1.89-10.47) days, respectively. Conclusion: The estimated course of COVID-19 and related epidemiological parameters are similar to the existing data.

Research Progress of Nano-preparation in Remodeling Tumor Microenvironment and Enhancing Immune Efficacy / 中国药学杂志

Because of the tumor barrier and the microenvironment of tumor tissue, the treatment of tumor immunotherapy is limited and increased adverse reactions. In recent years, nano-preparation has made many new advances in the process of tumor immunotherapy for regulating immune deficiency, remodeling tumor tissue microenvironment, and enhancing the effect of immunotherapy. This article mainly describes the microenvironmental factors of affecting the efficacy of tumor immunotherapy, and reviews the strategies of nano-preparation for remodeling the tumor microenvironment.

Investigation of antimicrobial resistance of Klebsiella pneumoniae and Pseudomonas aeruginosa isolates from rat-like animals around a hospital in Guangzhou / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate antimicrobial resistance of Klebsiella pneumoniae and Pseudomonas aeruginosa isolates in fecal samples from rat-like animals.</p><p><b>METHODS</b>Rat-like animals were captured using cages around a hospital and the neighboring residential area between March and October, 2015. K. pneumoniae and P. aeruginosa were isolated from the fecal samples of the captured animals. Antimicrobial susceptibility test was performed according to the guidelines of Clinical and Laboratory Standards Institute (2014).</p><p><b>RESULTS</b>A total of 329 rat-like animals were captured, including 205 Suncus murinus, 111 Rattus norvegicus, 5 Rattus flavipectus and 8 Mus musculus. The positivity rates of K. pneumoniae and P. aeruginosa were 78.4% and 34.7% in the fecal samples from the captured animals, respectively. K. pneumoniae isolates from Suncus murinus showed a high resistance to ampicillin, cephazolin, nitrofurantoin, piperacillin and cefotaxime (with resistance rates of 100%, 51.2%, 44.2%, 37.2%, and 23.3%, respectively), and K. pneumoniae isolates from Rattus spp. showed a similar drug-resistance profile. The prevalence rates of multidrug resistance and ESBLs were 40.9% and 10.7%, respectively. P. aeruginosa from both Suncus murinus and Rattus spp. exhibited the highest resistance rates to aztreonam (12.4% and 16.0%, respectively), followed by penicillins and fluoroquinolones. P. aeruginosa isolates were susceptible to cephems, aminoglycosides and carbapenems (with resistance rates below 5%).</p><p><b>CONCLUSION</b>K. pneumoniae and P. aeruginosa isolated from rat-like animals showed drug-resistance profiles similar to those of the strains isolated from clinical patients, suggesting that the possible transmission of K. pneumoniae and P. aeruginosa between rat-like animals and human beings.</p>

Intracytoplasmic morphologically selected sperm injection of testicular sperm: clinical outcome in azoospermia patients / 中华男科学杂志

<p><b>OBJECTIVE</b>To assess whether intracytoplasmic morphologically selected sperm injection (IMSI) of testicular sperm improves the clinical outcome in patients with azoospermia.</p><p><b>METHODS</b>We performed conventional intracytoplasmic sperm injection (ICSI) for 66 patients diagnosed with azoospermia and IMSI for another 39 using testicular sperm selected at high magnification ( x 6000), and comparatively analyzed the clinical outcomes of the two techniques.</p><p><b>RESULTS</b>There were no statistically significant differences between conventional ICSI and IMSI in the rates of pregnancy (51.52% vs. 56.41%) and implantation (30.67% vs. 35.29%), although the rate of early abortion was lower in the IMSI than in the ICSI group (4.50% vs. 11.76%).</p><p><b>CONCLUSION</b>IMSI of testicular sperm may effect a lower rate of early abortion than conventional ICSI in patients with azoospermia.</p>

Chemical constituents from Lespedeza virgata / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the chemical constituents of Lespedeza virgata.</p><p><b>METHOD</b>The constituents were isolated by column chromatography and their structures were elucidated by chemical properties and spectroscopic evideuce.</p><p><b>RESULT</b>Seven components were isolated and identified as quercetin 3-O-[2"-O-( E'-6"-O-feruloyl)-beta-D-glucopyranosyl]-beta-D-galact opyranoside (1), kaempferol-7-O-L-rhamnopyranoside (2), 7-O-alpha-L-rhamnopyransyl-kaempeferol-3-O-beta-D-glucopyranoside (3), quercetine (4), E-beta-hydroxycinnamic acid (5), protocatechuic acid (6), p-hydroxybenzoic (7).</p><p><b>CONCLUSION</b>Seven components are isolated from L. virgata for the first time.</p>

Cancer stem cells: its existence, proliferation and differentiation in an adenoid cystic carcinoma cell line / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the evidences of the presence of tumor stem cells and its impact on the tumorigenesis of adenoid cystic carcinoma cell (ACC)-2 cell line by analyzing the biologic characteristics of different sub-clones of adenoid cystic carcinoma cell line.</p><p><b>METHODS</b>In vitro individual cell culture was employed to observe the proliferating character of ACC-2 cells. The expression of CD44(+) and CD24(-) of ACC-2 cells were investigated by immunohistochemical. Immunomagnetic isolation of different phenotype of ACC-2 cells, followed by cell culture, was used to study the proliferating abilities of different clusters of the cell line. The hetero-transplanted tumor mold was established using BALB/C nude mice by subcutaneous injection of tumor cells. The tumorigenic and differentiating properties of the different cluster were investigated.</p><p><b>RESULTS</b>Only 4.41% of cultured ACC-2 cell had ability of division, proliferation and establishment of cell clone. CD44(+)-CD24(-) cluster accounted for about 8.1% of total ACC-2 cells, among which, 25.71% cells could divide and proliferate. All of CD44 and CD44(+)-CD24(+) cells were failure to be eternal alive in the condition of in vitro individual cell culture. According to the results of in vivo tumorigenic study, the minimal cell quantity to develop a subcutaneous transplanted tumor by CD44(+)-CD24(-) cells was 1 x 10(3), where as the needed cell amount were 1 x 10(5) and 1 x 10(4) as to non-isolated ACC-2 cells and CD44(+) cells, respectively. The CD44(-) and CD44(+)-CD24(+) did not develop transplanted tumors. CD44(+)-CD24(-) ACC-2 cell could differentiate into cells of other phenotypes.</p><p><b>CONCLUSIONS</b>CD44(+)-CD24(-) ACC-2 cells consist of a very small portion of all ACC-2 cells (about 4%). They have remarkable proliferating ability and can bear special phenotypes, The tumorogenic ability of CD44(+)-CD24(-) cells are stronger than that of CD44(+) and non-isolated ACC-2 cells. Eliminating of this cluster from ACC-2 would actually deprive the tumorogenic ability of the cell line.</p>

Experimental study of cisplatin loaded polylactic acid-polyethylene glycol nano-particles for targeting oral carcinoma / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the target deliver of Cisplatin to oral carcinoma tissues by intravenous injection of Cisplatin loaded polylactic acid- polyethylene glycol nanoparticles (CDDP-PLA-PEG-NP).</p><p><b>METHODS</b>CDDP-PLA-PEG-NP was prepared by the emulsion-solvent evaporation method. The buccal cancer model was established in 64 golden hamsters, which were divided randomly into two groups for 32 animals in each group, CDDP-PLA-PEG-NP (6.6 mg/kg) and CDDP (1 mg/kg) were respectively injected into mice tail vein. At 0.083, 0.5, 1, 2, 4, 6, 12, 24 h after drug administration. 4 animals in each group were sacrificed and CDDP concentration in the plasma and tumor were determined by high performance liquid chromatography. Targeting ability was evaluated by targeting index (TI), selectivity index (SI) and relative extraction efficiency (re).</p><p><b>RESULTS</b>The average diameter of CDDP-PLA-PEG-NP was (143.2 +/- 1.8) nm. The diameter distribution was from 103.5 nm to 175.8 nm. Drug loading and embedding ratio were (15.2 +/- 0.9) %, (89.0 +/- 0.8) % respectively. Values of TI and SI are more than 1 at 8 time points. The area under CDDP concentration-time curve of oral carcinoma tissues in CDDP-PLA-PEG-NP group was 10.36 times as many as that in CDDP group.</p><p><b>CONCLUSION</b>CDDP-PLA-PEG-NP can specifically deliver CDDP to oral carcinoma tissues by vein injection. Stealth anticancer nano-particle system can be regarded as a valuable drug deliver system to treat oral carcinoma.</p>

Dynamic observation of lung metastasis model of adenoid cystic carcinoma / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To form ACC-M-GFP cells by transfecting pEGFP-1 into ACC-M cells, and to build up lung metastasis model of adenoid cystic carcinoma for dynamic observation in simulated lung environment.</p><p><b>METHODS</b>pEGFP-1 was prepared and then transfected into ACC-M cell lines by using cationic lipid-based gene transfer technique. After successive selection, the ACC-M-GFP cells were collected and inoculated in BALB/C mice. The simulated lung environment was built up, and dynamic observation was performed by laser confocal microscopy within four weeks after transfection.</p><p><b>RESULTS</b>The amount of fluorescent tumor cell colonies and the intensity of fluorescence gradually increased from the second week to the forth week after transfection. In the meantime, only a very small number of tumor cells had the ability to form clones.</p><p><b>CONCLUSIONS</b>We successfully built up a lung metastasis model of adenoid cystic carcinoma for dynamic observation. The model is suitable for capturing and analyzing metastatic tumor cells in early stage.</p>

One-stage reconstruction of bilateral mandibular with free fibula flap / 中华外科杂志

<p><b>OBJECTIVE</b>To explore the method of clinical application and the efficacy of free fibula osteomyocutaneous flap in one-stage reconstruction of transmidline bilateral mandibular defect caused by giant neoplasms.</p><p><b>METHODS</b>From july 2000 to october 2002, transmidline bilateral mandibular defects caused by ameloblastoma (4 cases) and gingival carcinoma (2 cases), according to the character of defects, were reconstructed with free fibula osteomyocutaneous flaps. Peroneal artery and vein were used as vascular pedicle, the fibula was reshaped, and micro-titanium plates were used in rigid fixation between fibula and residue of bilateral mandible. Microvascular anastomoses were carried out between peroneal artery/vein and small artery/vein in neck.</p><p><b>RESULTS</b>Six free fibular osteomyocutaneous flaps survived well. Follow up duration ranged from 6 months to 2 years, the lower face appearance recovered well, occlusion relationship were normal, all patients were satisfactory with appearance and chewing function after repair of removable denture.</p><p><b>CONCLUSION</b>Free fibular osteomyocutaneous flap is a favorable material in the reconstruction of transmidline bilateral mandibular giant defect. The blood supplement of fibula is offered both by segmentral periosteum and nutrient artery from bone marrow, It is greatly benefit to reshaping as arched mandible.</p>

Transfection of the nm23-H1 gene into BcaCD885 cell line inhibits the potential of invasion, adhesion and mobility / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To transfect nm23-H1 into the BcaCD885 cell lines in order to get safe high-efficiency and low-toxicity, and to find out whether nm23-H1 could affect the invasion and metastases ability of BcaCD885 cell lines.</p><p><b>METHODS</b>Lipofect was used to transfect nm23-H1 into BcaCD885 cell lines; immunohistochemistry was used to detect the difference expression of nm23-H1 between transfected and non-transfected cell lines; then transwell-room and wash way were used to detect the difference of invasion and metastases ability between transfected and non-transfected cell lines.</p><p><b>RESULTS</b>PCMV-NEO-BAM system gave the stability expression of nm23-H1; there was significant different NDPKA expression between transfected and non-transfected BcaCD885 cell lines; the invasion and metastases ability of transfected BcaCD885 cell lines decreased obviously.</p><p><b>CONCLUSION</b>nm23-H1 can inhibit the metastases of BcaCD885 cell lines significantly.</p>