A colorimetric and SERS dual-mode aptasensor for the detection of Shiga toxin type II based on Mn/Fe-MIL(53)@AuNSs

Shiga toxin type II (Stx2), the major virulence component of enterohemorrhagic Escherichia coli, is strongly associated with the life-threatening hemolytic uremic syndrome thus posing a substantial risk to food safety and human health. In this work, a dual-mode aptasensor with colorimetric and surface-enhanced Raman scattering was developed for Stx2 specific detection based on noble metal nanoparticles and Raman reporter loaded metal-organic framework (Mn/Fe-MIL(53)@AuNSs-MBA). The Mn/Fe-MIL(53)@AuNSs could catalyze the H2O2-mediated oxidation of 3,3',5,5'-tetramethylbenzidine (TMB), thereby enabling visual detection. Meanwhile, the SERS signal from MBA can be enhanced by the decorated AuNSs. Under optimal conditions, a linear range of 0.05-500 ng/mL with limit of detection (LOD) of 26 pg/mL was achieved in colorimetric mode and a linear range of 5-1000 ng/mL with LOD of 0.82 ng/mL in SERS mode, in which the dual-mode results complement each other, widening the linear range, increasing the accuracy and reliability of the detection. The method was further applied to the detection of Stx2 in milk with average recovery of 101.1 %, demonstrating its superior potential for bacterial toxin monitoring.

Deoxynivalenol (DON)-Triggered Dual-Color Composite Probe Based on Gold Nanoclusters for Simultaneous Imaging of DON and miR-34a in Living Cells

Deoxynivalenol (DON) is a mycotoxin secreted by Fusarium species, posing great harm to food safety and human health. Therefore, it is of great significance to study its toxic effects and mechanism. miR-34a is a representative biomarker during the process of DON-induced apoptosis. Herein, a DON-triggered dual-color composite probe was constructed for simultaneous imaging of DON and miR-34a in living cells. The aptamer blocks the recognition sequence of miR-34a to realize DON-triggered cell imaging. The specific binding of DON with its aptamer and HCR induced by miR-34a resulted in the recovery of fluorescence of the dual-color Au NCs. Under the optimal conditions, the correlation between the relative fluorescence intensities of dual-color Au NCs showed good linear relationships with the logarithm of DON and miR-34a concentration, respectively. With the increase in DON concentration (0-20 μg/mL) and stimulation time (0-12 h), the fluorescence of dual-color Au NCs gradually recovered. This dual-color Au NCs composite probe can realize simultaneous detection of DON and miR-34a induced by DON, which is significant for verifying the cytotoxic mechanism of DON.

[Time characteristics of imported malaria cases in Yunnan Province]

Objective To investigate the time distribution characteristics and the epidemic trends of imported malaria cases in Yunnan Province. Methods The malaria case records and epidemiological history data of Yunnan Province were collected, and the local infection cases were excluded. The data were statistical analyzed. Results The imported malaria cases had a significantly seasonal periodicity (Q = 26.574, P < 0.05) and epidemic trends (Q = 35.487, P < 0.05). The imported peak was in May, while February was the lowest month of imported cases, and the difference was significant (Z = -2.619, P < 0.05). The simple seasonal prediction model was the best model (R² = 0.677, BIC = 4.867) for forecast while the residual sequence was white noise (Q = 14.226, P > 0.05). By using the model to predict the cases in January, February and March of 2016, the number (95% CI) were 29 (7-50), 22 (0-44) and 31 (8-54), and the actual number of imported malaria cases were 29, 24 and 38 cases respectively and all cases were included in the 95% CI. Conclusion The imported malaria cases in Yunnan Province had a significantly seasonal periodicity and epidemic trends, and the established model has good prediction on the recent cases.

Compound heterozygous mutations in TTC7A cause familial multiple intestinal atresias and severe combined immunodeficiency

Familial multiple intestinal atresias is an autosomal recessive disease with or without combined immunodeficiency. In the last year, several reports have described mutations in the gene TTC7A as causal to the disease in different populations. However, exact correlation between different genotypes and various phenotypes are not clear. In this study, we report identification of novel compound heterozygous mutations in TTC7A gene in a Malay girl with familial multiple intestinal atresias and severe combined immunodeficiency (MIA-SCID) by whole exome sequencing. We found two mutations in TTC7A: one that destroyed a putative splicing acceptor at the junction of intron 17/exon 18 and one that introduced a stop codon that would truncate the last two amino acids of the encoded protein. Reviewing the recent reports on TTC7A mutations reveals correlation between the position and nature of the mutations with patient survival and clinical manifestations. Examination of public databases also suggests carrier status for healthy individuals, making a case for population screening on this gene, especially in populations with suspected frequent founder mutations.

Impact of nursing home residence on hospital epidemiology of meticillin-resistant Staphylococcus aureus: a perspective from Asia

In a Singapore hospital practising meticillin-resistant Staphylococcus aureus (MRSA) admission screening, the relative risk for MRSA colonization for those admitted from nursing homes was 6.89 (95% confidence interval: 5.74-8.26; 41% of 190 vs 6.0% of 14,849). However, the MRSA burden on admission attributable to nursing home residence was low (6.9%). Risk factors independently associated with MRSA colonization in patients admitted from nursing homes were previous hospital admissions, broken skin, prior use of antibiotics and Chinese ethnicity. Low rates of nursing home use means that the overall impact of nursing home residence on MRSA in our hospital is low.

Diffusion-weighted magnetic resonance imaging in patients with known or suspected breast malignancy: Correlation between apparent diffusion coefficient and histopathologic diagnoses

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Background: Magnetic resonance imaging (MRI) is an important imaging modality for evaluating patients at high risk for breast malignancy. However, the role and utility of diffusion-weighted imaging (DWI) in breast MRI has not been fully elucidated. This study was designed to investigate the relationship between apparent diffusion coefficient (ADC) values and histopathologic diagnoses in benign and malignant breast pathologies as well as to assess the relative diagnostic value of this parameter.

Methods: We searched our database for patients who received breast MRI studies from February 2010 through March 2011. We then identified those patients who had either known or suspected breast malignancy and who had also undergone DWI. Breast abnormalities were identified through a review of the short tau inversion recovery (STIR) and T1-weighted pre- and post-contrast images. DWI images were evaluated and the corresponding ADC values were calculated. These lesions were correlated with histopathologic results when available.

Results: A total of 174 patient MRI studies were evaluated. Single dominant lesions were assessed and included biopsy-proven infiltrating ductal carcinoma (IDC), biopsy-proven ductal carcinoma in situ (DCIS), and benign lesions including cysts. The median ADC value for IDC was 118 x 10-5 mm2 s-1. The median ADC value for DCIS was 123 x 10-5 mm2 s-1. Finally, the median ADC value for breast cysts was 217 x 10-5 mm2 s-1.

Conclusions: As the role of MRI continues to evolve in the evaluation of breast pathology, the addition of DWI may increase diagnostic confidence for breast cancer, allowing for further differentiation from benign lesions. DWI is feasible to implement in many clinical practices and correlates with imaging features of breast cancer. The DWI images are acquired rapidly and without intravenous contrast. This method of imaging could be used in short intervals to assess treatment response to therapies such as biologic inhibitors or radiation therapy.

Analysis of Kerr effect in resonator fiber optic gyros with triangular wave phase modulation

We present an in-depth analysis of the Kerr effect in resonator fiber optic gyros (R-FOGs) based on triangular wave phase modulation. Formulations that relate gyro output to the rotation rate, the Kerr nonlinearity, and other fiber and gyro parameters are derived and used to study the effect of Kerr nonlinearity on the gyro performance. Numerical investigation shows that the Kerr effect results in a nonzero gyro output even when the gyro is at stationary, which is interpreted as an error in the measurement of rotation rate. This error was found to increase as the frequencies of the two triangular phase modulations deviate from each other, and is not zero even if the intensities of the two counterpropagating beams are exactly the same. For fixed frequencies of the triangular phase modulations, there exists an optimal intensity splitting ratio for the two counterpropagating beams, which leads to zero gyro error. Calculation shows that the measurement error due to the Kerr effect for an R-FOG with a hollow-core photonic bandgap fiber as the fiber loop can be one to two orders of magnitude smaller than an R-FOG with a conventional single mode fiber loop.

Comparative observation with MRI and pathology of brain edema at the early stage of severe burn

OBJECTIVE

To investigate the correlation between MRI features and pathology in brain edema at the early stage of severe burn (5 0% TBSA III degree) in dogs.

METHODS

Fifty-two dogs were randomized into control, simple b urn (SB), burn plus sodium lactate (BSL), and burn plus glucose solution groups (BGS). The manifestation of the brain of control group was compared with that of burn groups at 6, 12, 18 and 24 hours postburn with MRI and pathological examination (gross appearance, electron microscopy and light microscopy).

RESULTS

The earliest findings of brain edema were seen at 12 h ours after burn in BGS group, in which brain swelling was the main feature of MR I. The decrease of SIR on T(1)WI was not observed until it was exceeded 10%. Sig nal of T(2)WI increased by 8.29% at 24 hours after burn. It was difficult to distinguish the gray matter from the white matter at the boundary line, which became blurred later. Histological changes of brain edema were observed as early as 6 hours after burn, being accompanied by swelling of endothelial cells and peri-vescular astrocytes, and vacuolation took place in neurons at 12 hours after burn, with different degrees of necrosis of capillary endothelium, neurons, and axons. These changes became more marked with elapse of time. The BGS group showed the most obvious changes mentioned above at 24 hours after burn.

CONCLUSIONS

The model of the brain edema after severe burn has the feature of both vasogenic edema and cytotoxic edema on the MRI and pathology. Positive MRI findings lagged behind that of the pathomorphological changes.

[Application of triple-color flow cytometry for minimal residual disease detection in acute B-lymphoblastic leukemia]

OBJECTIVE

To set up a sensitive triple-color flow cytometric assay (FCM) for detection of residual leukemia cells.

METHODS

Application of triple-color flow cytometry to the patients for detecting CD(10)(+)CD(22)(+)CD(45)(- or dim) leukemic cells in acute B lymphoblastic leukemia (B-ALL).

RESULTS

Leukemic cells in B-ALL patients' bone marrow (BM) consistently showed the CD(10)(+)CD(22)(+)CD(45)(- or dim) phenotype. FCM analysis could detect leukemic cells at the level of 1 per 10(4) cells. The CD(10)(+)CD(22)(+)CD(45)(- or dim) cell population was absent in normal BM, regenerating BM, and BM from leukemia patients in continuous complete remission. This assay could identify residual leukemic cells in 50 days after starting induction chemotherapy. Furthermore, a gradual increase of leukemic cell population could be monitored by this assay before morphological confirmation of BM relapse.

CONCLUSION

Triple-color FCM was a sensitive method for detecting BM CD(10)(+)CD(22)(+)CD(45)(minus sign or dim) leukemic cells and could be an additional useful tool to monitor MRD in B-ALL patients.

[A canine model of brain edema established in the early postburn stage]

OBJECTIVE

To establish a canine model of brain edema in the early stage of severe burn.

METHODS

Mongrel dogs were inflicted by napalm with 50% TBSA III degree burn. The dogs were randomized into normal control (C), burn (B), burn with balanced salt solution (S) and burn with glucose (G) groups. The macropathological, histopathological and ultrastructural changes of brain tissue and brain water (%) were examined at 6, 12, 18 and 24 postburn hours (PBH), respectively, with simultaneous evaluation of blood brain barrier by (99) TC -- ECD.

RESULTS

Pathological evidence of brain edema exhibited at as early as 6 PBH in B, S and G groups, which included cellular swelling of partial endothelia and pericapillary astrocytes, and ischemic necrosis of endothelia, neurons and axons to varying degrees. All the changes exhibited more and more obvious with the elapse of postburn time. The brain water content in each burn group, especially in G group at 24 PBH, was more than that in C group. It was indicated by nuclide imaging that there appeared gradual increasing of the concentration of (99) TC -- ECD in brain tissue in B and C groups since 6 PBH.

CONCLUSION

This model was established for the convenience of burn scholars to study the pathogenesis and management of postburn brain edema.

[Cord blood plasma selectively stimulates the expansion of hematopoietic pregenitor cells in vitro]

OBJECTIVE

To explore the effect of cord blood (CB) plasma on the expansion of hematopoietic progenitor cells.

METHODS

The effect of CB plasma on the expansion of CB and bone marrow (BM)-derived hematopoietic progenitor cells was studies and compared with those of adult's peripheral blood (PB) plasma and cytokines such as IL-3 and SCF.

RESULTS

(1) CB plasma increased CFU yields of CB-derived progenitor cells by 2.23 +/- 0.52-fold and this expansion was dependent on CB plasma concentrations supplemented in the cultures. Greater expansion of progenitor cells was found when ABO was unmatched between the CB-derived cells and CB plasma. (2) Stimulating effect of CB plasma on BM-derived progenitor cells was also related to ABO type. CFU yields were increased by 1.55 +/- 0.43-fold when ABO was unmatched and not increased when ABO was matched. (3) Expansion of CB-derived progenitor cells by IL-3 and SCF was revealed. Significant increase in CFU yields occurred in the addition of both the cytokine and the CB plasma. (4) No expansion occurred in CB-and BM-derived cell cultures supplemented with PB plasma.

CONCLUSION

There is factor(s) selectively stimulating expansion of progenitor cells in CB plasma. It may be beneficial that CB plasma was transfused with CB-derived stem cell transplantation.

Psychosis and genes with trinucleotide repeat polymorphism

Abnormal expansion of genes with trinucleotide repeat (TNR) polymorphism has been found in a number of neuropsychiatric disorders. These disorders and the major psychoses, schizophrenia and bipolar affective disorder, appear to share an interesting phenomenon: genetic anticipation. Because TNR expansion correlates with anticipation, these unstable DNA sites are considered important candidate loci for the major psychoses. We investigated genes with TNR polymorphisms, including B1, B33, B37, and the N-cadherin gene, in unrelated Caucasian North American and Italian schizophrenics (n = 53 to 74), and matched controls. Also, unrelated Caucasian North American patients with bipolar I affective disorder were screened for the B33 and N-cadherin genes (n = 49 and 63, respectively). No unusually long alleles that would suggest abnormal expansion of the TNR were observed for any of these genes. Also, no statistically significant results were found in tests for genetic association between any of these genes and schizophrenia. For B37, a trend toward a difference in allele counts between schizophrenics and controls was observed. However, no clear evidence for a role of these TNR-containing genes in schizophrenia or bipolar affective disorders was found.

Collateral circulatory development in skeletal muscle

The arterial collateral anastomoses in rectus abdominis of the dog are employed as an animal model. The dynamic changes of collateral channels have been uncovered during roestablishment of collateral circulation. The experimental results display the 3 morphological characters, calibre dilatation, cell proliferation, and vessel reconstruction, at different time intervals in the collateral development. It provides evidence that some useful programme can be added to get a more effective collateral circulatory function in clinical practice.