OBJECTIVETo observe the effect of amino acid substitution in conserved sequence of penicillin-binding protein (PBP) 1A, 2B, 2X on antimicrobial activity of beta-lactams against Streptococcus pneumoniae (SP).

METHODMinimal inhibitory concentration (MIC) of 6 beta-lactams was determined by the E-test in 59 SP strains. The penicillin-binding protein genes pbp1a, 2b, 2x in every SP strain were amplified by nested-polymerase chain reaction (nPCR), then the PCR products were sequenced using automatic genetic analyzer directly. To analyze the amino acid substitutions, the DNA sequences were converted to protein sequences and aligned by Clustalx software. According to amino acid substitution in conserved sequence of PBP2B, 3 phenotypes were observed, including: PBP2B phenotype I (no amino acid substitution); PBP2B phenotype II (Glutamine 432-->Leucine and/or Threonine 445/451-->Alanine/Serine, Glutamic 481-->Glycine, 1 strain had proline insertion between residues 431/432); PBP2B phenotype III (Alanine 624-->Glycine with the addition of phenotype II). According to amino acid substitution in conserved sequence of PBP1A, 3 phenotypes were observed, including: PBP1A phenotype I (no amino acid substitution); PBP1A phenotype II (Threonine 574-->Asparagine, Serine 575-->Threonine, Glutamine 576-->Glycine, Phenylalanine 577-->Tyrosine, 574TSQF-->NTGY); PBP1A III (Threonine 371-->Alanine/Serine, Proline 432-->Threonine with the addition of 574TSQF-->NTGY). According to amino acid substitution in conserved sequence of PBP2X, 4 phenotypes were observed, including: PBP2X phenotype I (no amino acid substitution); PBP2X phenotype II (Histidine 394-->Leucine or Threonine 338-->Alanine); PBP2X phenotype III (Threonine 338-->Alanine, Isoleucine 371-->Threonine, Arginine 384-->Glycine and Leucine 546-->Valine); PBP2X phenotype IV (Methionine 339-->Phenylalanine, Methionine 400-->Threonine with the addition of PBP2X phenotype III).

RESULTAmong 59 SP strains antibacterial activities distribution (sensitive strains, intermediate strains and resistant strains) of 6 beta-lactams were penicillin (12, 29, 18); amoxicillin(49, 9, 1); cefuroxime (16, 16, 27); ceftriaxone (47, 1, 11); cefotaxime (47, 3, 9); imipenem (49, 10, 0). beta-lactam antibiotics insensitive strains (intermediate + resistant strain) in PBP2B phenotype III, PBP1A phenotype III, PBP2X phenotype III and IV were significantly increased, the MIC(50) of these strains were significantly higher than that of the others.

CONCLUSIONThe amino acid substitutions in or vicinal conserved sequence of PBP of SP increase MIC for beta-lactam antibiotics.

Amino Acid Substitution ; Aminoacyltransferases ; genetics ; Anti-Bacterial Agents ; pharmacology ; Bacterial Proteins ; genetics ; Microbial Sensitivity Tests ; Penicillin-Binding Proteins ; genetics ; Peptidyl Transferases ; genetics ; Streptococcus pneumoniae ; drug effects ; beta-Lactam Resistance ; genetics ; beta-Lactams ; pharmacology

Objective] To study hepatitis B virus ( HBV) mother-to-child transmission and the impact factors, providing the basis for preventive strategies. [ Methods ] A total of 154 hepatitis B surface antigen ( HBsAg ) -positive pregnant women and 297 HBsAg -negative pregnant women from Baoshan District Centers for Disease Control and Prevention in Shanghai were enrolled and received an epidemiological survey regarding mother-to-child transmission.Mothers'peripheral blood and newborns'cord blood were collected to be tested for HBV serological markers and HBV DNA load.HBsAg positivity and HBV DNA≥103 copies/mL in cord blood of newborns born of HBsAg-positive mothers was defined as trans-placental HBV transmission. [ Results] The trans-placental transmission rate was found to be 8.4%for HBsAg-positive mothers.Trans-placental transmission rate was significantly higher among both HBsAg and HBeAg -positive women compared to those only with HBsAg -positiveness ( 20.0% vs. 3.7%, relative risk was 5.41, P <0.05), and increased with HBV DNA load in mothers'peripheral blood. [ Conclusion] HBeAg can directly transmit through the placenta, while HBsAg is“filtered” to a certain degree.HBeAg positiveness and high HBV DNA load of the mother are risk factors in trans-placental transmission, and possibly lead to the failure of newborn immunoprophylaxis.

The acquisition of metastasis potential is a critical point for malignant tumors. Melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24) is a potential tumor suppress gene and frequently down-regulated in malignant tumors. It has been implicated that overexpression of MDA-7 led to proliferation inhibition in many types of human tumor. Invasion is an important process which is potential to promote tumor metastasis. However, the role and potential molecular mechanism of mda-7/IL-24 to inhibit the invasion of human melanoma cancer is not fully clear. In this report, we identified a solid role for mda-7/IL-24 in invasion inhibition of human melanoma cancer LiBr cells, including decreasing of adhesion and invasion in vitro, blocking cell cycle, down-regulating the expression of ICAM-1, MMP-2/9, CDK1, the phosphorylation of ERK and Akt, NF-kappaB and AP-1 transcription activity. Meanwhile, there was an increased expression of PTEN in mda-7/IL-24 over-expression LiBr cells. Our results demonstrated that mda-7/IL-24 is a potential invasion suppress gene, which inhibits the invasion of LiBr cells by the down-regulation of ICAM-1, MMP-2/9, PTEN, and CDK1 expression. The molecular pathways involved were the MAPK/ERK, PI3K-Akt, NF-kappaB, and AP-1. These findings suggest that mda-7/IL-24 may be used as a possible therapeutic strategy for human melanoma cancer.
CDC2 Protein Kinase/genetics/metabolism ; Cell Line, Tumor ; Cell Movement ; Down-Regulation ; G2 Phase Cell Cycle Checkpoints ; Humans ; Intercellular Adhesion Molecule-1/genetics/metabolism ; Interleukins/genetics/*metabolism ; M Phase Cell Cycle Checkpoints ; Matrix Metalloproteinase 2/genetics/metabolism ; Matrix Metalloproteinase 9/genetics/metabolism ; Melanoma/metabolism/pathology ; NF-kappa B/genetics/metabolism ; PTEN Phosphohydrolase/genetics/metabolism ; Phosphorylation ; Proto-Oncogene Proteins c-akt/genetics/metabolism ; Transcription Factor AP-1/genetics/metabolism ; Up-Regulation

Objective To test the changes of the potassium(K+)and magnesium(Mg2+)concentrations in vitreous humor of rabbits along with postmortem interval(PMI)under different temperatures, and explore the feasibility of PMI estimation using mixed-effect model. Methods After sacrifice, rabbit carcasses were preserved at 5℃, 15℃, 25℃ and 35℃, and 80-100μL of vitreous humor was collected by the double-eye alternating micro-sampling method at every 12 h. The concentrations of K+and Mg2+in vitreous humor were measured by a biochemical-immune analyser. The mixed-effect model was used to perform analy-sis and fitting, and established the equations for PMI estimation. The data detected from the samples that were stoned at 10℃, 20℃ and 30℃ with 20, 40 and 65 h were used to validate the equations of PMI estimation. Results The concentrations of K+and Mg2+[f(x,y)] in vitreous humor of rabbits under different temperature increased along with PMI(x). The relative equations of K+and Mg2+concentration with PMI and temperature under 5℃~35℃ were fK+(x,y)=3.413 0+0.309 2 x+0.337 6 y+0.010 83 xy-0.002 47 x2 (P<0.000 1), and fMg2+(x,y)=0.745 6+0.006 432 x+0.033 8 y(P<0.000 1), respectively. It was proved that the time of deviation for PMI estimation by K+and Mg2+was in 10 h when PMI was between 0 to 40 h, and the time of deviation was in 21 h when PMI was between 40 to 65 h. Conclusion In the ambient temperature range of 5℃-35℃, the mixed-effect model based on temperature and vitreous humor sub-stance concentrations can provide a new method for the practical application of vitreous humor chemi-cals for PMI estimation.

Postmortem interval (PMI) estimation is one of the most challenging problems in the field of forensic science. Vitreous humor is a hotspot which has been used for PMI estimation and postmortem chemical analysis in forensic pathology. In order to provide novel perspectives for the future research of PMI estimation using vitreous humor, the comparison between vitreous humor with other common body fluids, the effect of temperature on vitreous humor, vitreous humor detection method and data fitting method have been reviewed in this paper.

BACKGROUNDThis study was to investigate the relationship among aortic artery calcification (AAC), cardiac valve calcification (CVC), and mortality in maintenance hemodialysis (MHD) patients.

METHODSAll MHD patients in Shanghai Ruijin Hospital in July 2011 were included. To follow up for 42 months, clinical data, predialysis blood tests, echocardiography, and lateral lumbar X-ray plain radiography results were collected. Plasma FGF23 level was measured using a C-terminal assay.

RESULTSTotally, 110 MHD patients were involved in this study. Of which, 64 (58.2%) patients were male, the mean age was 55.2 ± 1.4 years old, and the median dialysis duration was 29.85 (3.0-225.5) months. About 25.5% of the 110 MHD patients had CVC from echocardiography while 61.8% of the patients had visible calcification of aorta from lateral lumbar X-ray plain radiography. After 42 months follow-up, 25 (22.7%) patients died. Kaplan-Meier analysis showed that patients with AAC or CVC had a significant greater number of all-cause and cardiovascular deaths than those without. In multivariate analyses, the presence of AAC was a significant factor associated with all-cause mortality (hazard ratio [HR]: 3.149, P = 0.025) in addition to lower albumin level and lower 25-hydroxy Vitamin D (25(OH)D) level. The presence of CVC was a significant factor associated with cardiovascular mortality (HR: 3.800, P = 0.029) in addition to lower albumin level and lower 25(OH)D level.

CONCLUSIONLateral lumbar X-ray plain radiography and echocardiography are simple methods to detect AAC and CVC in dialysis patients. The presence of AAC and CVC was independently associated with mortality in MHD patients. Regular follow-up by X-ray and echocardiography could be a useful method to stratify mortality risk in MHD patients.

Aortic Diseases ; blood ; complications ; Calcinosis ; blood ; complications ; China ; Female ; Fibroblast Growth Factors ; blood ; Follow-Up Studies ; Heart Valve Diseases ; blood ; complications ; Heart Valves ; pathology ; Humans ; Male ; Middle Aged ; Proportional Hazards Models ; Renal Dialysis ; mortality

Objective: To evaluate the feasibility of dynamic contrast-enhanced MRI (DCE-MRI) in differentiating tumor deposits (TDs) from metastatic lymph nodes (MLNs) in rectal cancer. Materials and Methods: A retrospective analysis was conducted on 70 patients with rectal cancer, including 168 lesions (70 TDs and 98 MLNs confirmed by histopathology), who underwent pretreatment MRI and subsequent surgery between March 2019 and December 2022. The morphological characteristics of TDs and MLNs, along with quantitative parameters derived from DCE-MRI (K trans , kep, and v e) and DWI (ADCmin, ADCmax, and ADCmean), were analyzed and compared between the two groups.Multivariable binary logistic regression and receiver operating characteristic (ROC) curve analyses were performed to assess the diagnostic performance of significant individual quantitative parameters and combined parameters in distinguishing TDs from MLNs. Results: All morphological features, including size, shape, border, and signal intensity, as well as all DCE-MRI parameters showed significant differences between TDs and MLNs (all P < 0.05). However, ADC values did not demonstrate significant differences (all P > 0.05). Among the single quantitative parameters, v e had the highest diagnostic accuracy, with an area under the ROC curve (AUC) of 0.772 for distinguishing TDs from MLNs. A multivariable logistic regression model incorporating short axis, border, v e, and ADC mean improved diagnostic performance, achieving an AUC of 0.833 (P = 0.027). Conclusion The combination of morphological features, DCE-MRI parameters, and ADC values can effectively aid in the preoperative differentiation of TDs from MLNs in rectal cancer.

Objective: To evaluate the feasibility of dynamic contrast-enhanced MRI (DCE-MRI) in differentiating tumor deposits (TDs) from metastatic lymph nodes (MLNs) in rectal cancer. Materials and Methods: A retrospective analysis was conducted on 70 patients with rectal cancer, including 168 lesions (70 TDs and 98 MLNs confirmed by histopathology), who underwent pretreatment MRI and subsequent surgery between March 2019 and December 2022. The morphological characteristics of TDs and MLNs, along with quantitative parameters derived from DCE-MRI (K trans , kep, and v e) and DWI (ADCmin, ADCmax, and ADCmean), were analyzed and compared between the two groups.Multivariable binary logistic regression and receiver operating characteristic (ROC) curve analyses were performed to assess the diagnostic performance of significant individual quantitative parameters and combined parameters in distinguishing TDs from MLNs. Results: All morphological features, including size, shape, border, and signal intensity, as well as all DCE-MRI parameters showed significant differences between TDs and MLNs (all P < 0.05). However, ADC values did not demonstrate significant differences (all P > 0.05). Among the single quantitative parameters, v e had the highest diagnostic accuracy, with an area under the ROC curve (AUC) of 0.772 for distinguishing TDs from MLNs. A multivariable logistic regression model incorporating short axis, border, v e, and ADC mean improved diagnostic performance, achieving an AUC of 0.833 (P = 0.027). Conclusion The combination of morphological features, DCE-MRI parameters, and ADC values can effectively aid in the preoperative differentiation of TDs from MLNs in rectal cancer.

Objective: To evaluate the feasibility of dynamic contrast-enhanced MRI (DCE-MRI) in differentiating tumor deposits (TDs) from metastatic lymph nodes (MLNs) in rectal cancer. Materials and Methods: A retrospective analysis was conducted on 70 patients with rectal cancer, including 168 lesions (70 TDs and 98 MLNs confirmed by histopathology), who underwent pretreatment MRI and subsequent surgery between March 2019 and December 2022. The morphological characteristics of TDs and MLNs, along with quantitative parameters derived from DCE-MRI (K trans , kep, and v e) and DWI (ADCmin, ADCmax, and ADCmean), were analyzed and compared between the two groups.Multivariable binary logistic regression and receiver operating characteristic (ROC) curve analyses were performed to assess the diagnostic performance of significant individual quantitative parameters and combined parameters in distinguishing TDs from MLNs. Results: All morphological features, including size, shape, border, and signal intensity, as well as all DCE-MRI parameters showed significant differences between TDs and MLNs (all P < 0.05). However, ADC values did not demonstrate significant differences (all P > 0.05). Among the single quantitative parameters, v e had the highest diagnostic accuracy, with an area under the ROC curve (AUC) of 0.772 for distinguishing TDs from MLNs. A multivariable logistic regression model incorporating short axis, border, v e, and ADC mean improved diagnostic performance, achieving an AUC of 0.833 (P = 0.027). Conclusion The combination of morphological features, DCE-MRI parameters, and ADC values can effectively aid in the preoperative differentiation of TDs from MLNs in rectal cancer.

Objective: To evaluate the feasibility of dynamic contrast-enhanced MRI (DCE-MRI) in differentiating tumor deposits (TDs) from metastatic lymph nodes (MLNs) in rectal cancer. Materials and Methods: A retrospective analysis was conducted on 70 patients with rectal cancer, including 168 lesions (70 TDs and 98 MLNs confirmed by histopathology), who underwent pretreatment MRI and subsequent surgery between March 2019 and December 2022. The morphological characteristics of TDs and MLNs, along with quantitative parameters derived from DCE-MRI (K trans , kep, and v e) and DWI (ADCmin, ADCmax, and ADCmean), were analyzed and compared between the two groups.Multivariable binary logistic regression and receiver operating characteristic (ROC) curve analyses were performed to assess the diagnostic performance of significant individual quantitative parameters and combined parameters in distinguishing TDs from MLNs. Results: All morphological features, including size, shape, border, and signal intensity, as well as all DCE-MRI parameters showed significant differences between TDs and MLNs (all P < 0.05). However, ADC values did not demonstrate significant differences (all P > 0.05). Among the single quantitative parameters, v e had the highest diagnostic accuracy, with an area under the ROC curve (AUC) of 0.772 for distinguishing TDs from MLNs. A multivariable logistic regression model incorporating short axis, border, v e, and ADC mean improved diagnostic performance, achieving an AUC of 0.833 (P = 0.027). Conclusion The combination of morphological features, DCE-MRI parameters, and ADC values can effectively aid in the preoperative differentiation of TDs from MLNs in rectal cancer.