基于估计补偿的医学显微图像拼接技术

图像拼接能很好地解决显微镜高倍镜成像时视野减小的问题.我们在分析显微成像系统对医学显微图像灰度分布影响的基础上,提出了一个系统对图像灰度分布的影响函数.结合系统影响函数和精确匹配下的相关性方程,得到一个以最小平方和形式误差函数为基础的方程组.利用奇异值分解得到系统对图像灰度分布的影响的估计值,然后用估计值来补偿系统的影响,得到图像的原始灰度,再进行拼接.这种方法能在不影响拼接速度的前提下消除医学显微图像中存在的拼接缝和拼接痕迹.     

管花苷B对抗H202诱导的PCI2细胞凋亡

目的:观察肉苁蓉提取物管花苷B对H:O:诱导的PCI2细胞损伤的影响.方法:用MTr法检测细胞存活率,以激光共聚焦显微镜荧光染色法检测细胞内活性氧的产生和线粒体膜电位的变化,DNA琼脂糖凝胶电泳和流式细胞仪检测细胞凋亡的发生,并用荧光酶标仪测定caspase-3的活性.结果:100 μmol稬-1H2O2处理细胞24 h显著降低细胞的存活率;诱导细胞发生凋亡,凋亡率达48.O％;细胞内活性氧水平及caspase-3的活性显著升高;而线粒体膜电位却明显降低,红／绿荧光强度的比值由正常的5.97降低为0.41左右.而预先给予l、10或100 mg.L-1浓度的管花苷B处理细胞12 h,可显著提高细胞存活率;并可有效抑制DNA ladder的发生;流式细胞仪检测凋亡率分别降低到30.9％、18.3％和6.2％;激光共聚焦显微镜结果显示管花苷B可明显降低细胞内活性氧的水平;并可逐渐恢复线粒体的高能量状态;easpase-3的活性不断降低,并呈现了一定的剂量依赖性.结论:管花苷B能显著地抑制H2O2诱导的PCI2细胞凋亡,其神经细胞保护作用可能与其降低细胞内活性氧水平,维持线粒体膜电位的高能状态和抑制caspase-3的活性有关.     

IL-1 up-regulates osteopontin expression in experimental crescentic glomerulonephritis in the rat

Osteopontin (OPN) is a macrophage chemotactic and adhesion molecule that acts to promote macrophage infiltration in rat anti-glomerular basement membrane (GBM) glomerulonephritis. The present study investigated the role of interleukin-1 (IL-1) in the up-regulation of renal OPN expression in this disease model. Accelerated anti-GBM glomerulonephritis was induced in groups of six rats. Animals were treated by a constant infusion of the IL-1 receptor antagonist or saline (control) over days -1 to 14 (induction phase) or days 7 to 21 (established disease). In normal rat kidney, OPN was expressed in a few tubules (<5%) and absent from glomeruli. During the development of rat anti-GBM disease (days 7 to 21), there was substantial up-regulation of OPN mRNA and protein expression in glomeruli (>5 cells per glomerular cross-section) and tubular epithelial cells (50-75% OPN-positive). Up-regulation of OPN expression was associated with macrophage accumulation within the kidney, severe proteinuria, loss of renal function, and severe histological damage including glomerular crescentic formation and tubulointerstitial fibrosis. In contrast, IL-1 receptor antagonist treatment of either the induction phase of disease or established disease significantly reduced OPN mRNA and protein expression in glomeruli (/75-85%, P < 0.001) and tubules (/45-60%, P < 0.001). The reduction in OPN expression was associated with significant inhibition of macrophage accumulation and progressive renal injury. In vitro, the addition of IL-1 to the normal rat tubular epithelial cell line NRK52E up-regulated OPN mRNA and protein levels, an effect that was dose-dependent and inhibited by the addition of IL-1 receptor antagonist, thus demonstrating that IL-1 can act directly to up-regulate renal OPN expression. In conclusion, this study provides in vivo and in vitro evidence that IL-1 up-regulates OPN expression in experimental kidney disease and support for the argument that inhibition of OPN expression is one mechanism by which IL-1 receptor antagonist treatment suppresses macrophage-mediated renal injury.     

Malignant granular cell tumor at the retrotracheal space

We report a case of an extremely rare neoplasm, malignant granular cell tumor (MGCT). The patient was a 21-year-old woman, who was 5 months pregnant. The tumor occurred in the retrotracheal space, extending from the level of the larynx to the thoracic inlet. In addition, there were multiple, variable-sized tumor nodules within both lung fields on chest CT scan. Histologically, tissue biopsied from the periphery of the tumor consisted of solid sheets of large ovoid cells with ample, eosinophilic cytoplasm, eccentric nuclei, and prominent nucleoli. Each cell showed slight atypism of the nuclei. There was a focal necrosis at the periphery of the lesion. These cells stained strongly for S-100 protein, neuron-specific enolase (NSE) and CD68. On electron microscopy, the tumor cells contained autophagic vacuoles. The patient refused further treatment and died 7 months later. The exact cause of death was not known. Until now, the diagnosis of MGCTs has been made only when metastasis and an aggressive clinical course are identified, although some observers advocate that some histologic features such as nuclear pleomorphism, necrosis, and the presence of any mitotic activity are indicative of malignancy. These histologic findings are not easily detectable in every case of MGCT, as in our case. So the diagnosis of a MGCT should be considered in cases with aggressive clinical findings and some histologic features, such as necrosis, nuclear atypism, and mitotic activities, which could suggest the malignant behavior of this neoplasm.     

Antibody dynamics to SARS-CoV-2 in asymptomatic COVID-19 infections

Background

The missing asymptomatic COVID-19 infections have been overlooked because of the imperfect sensitivity of the nucleic acid testing (NAT). Globally understanding the humoral immunity in asymptomatic carriers will provide scientific knowledge for developing serological tests, improving early identification, and implementing more rational control strategies against the pandemic.

Measure

Utilizing both NAT and commercial kits for serum IgM and IgG antibodies, we extensively screened 11 766 epidemiologically suspected individuals on enrollment and 63 asymptomatic individuals were detected and recruited. Sixty-three healthy individuals and 51 mild patients without any preexisting conditions were set as controls. Serum IgM and IgG profiles were further probed using a SARS-CoV-2 proteome microarray, and neutralizing antibody was detected by a pseudotyped virus neutralization assay system. The dynamics of antibodies were analyzed with exposure time or symptoms onset.

Results

A combination test of NAT and serological testing for IgM antibody discovered 55.5% of the total of 63 asymptomatic infections, which significantly raises the detection sensitivity when compared with the NAT alone (19%). Serum proteome microarray analysis demonstrated that asymptomatics mainly produced IgM and IgG antibodies against S1 and N proteins out of 20 proteins of SARS-CoV-2. Different from strong and persistent N-specific antibodies, S1-specific IgM responses, which evolved in asymptomatic individuals as early as the seventh day after exposure, peaked on days from 17 days to 25 days, and then disappeared in two months, might be used as an early diagnostic biomarker. 11.8% (6/51) mild patients and 38.1% (24/63) asymptomatic individuals did not produce neutralizing antibody. In particular, neutralizing antibody in asymptomatics gradually vanished in two months.

Conclusion

Our findings might have important implications for the definition of asymptomatic COVID-19 infections, diagnosis, serological survey, public health, and immunization strategies.

     

Serological detection of infection with diverse human and simian immunodeficiency viruses using consensus env peptides

Cross-species transmission has been shown to play an important role in the emergence of human retroviruses. We developed a generic enzyme immunoassay using synthetic peptides from gp41 and C2V3 consensus sequences (human immunodeficiency virus [HIV] type 1 [HIV-1] groups M, O, and N and the homologous region of simian immunodeficiency virus [SIV] strains from chimpanzees [SIVcpz], SIVcpzGAB1 and SIVcpzANT) to detect divergent HIV and SIV. A cocktail of peptides from gp41 and C2V3 (M-O) detected all HIV-1 group M and O sera and showed cross-reactivity with SIVcpz sera. Further, a mixture of C2V3 peptides (GAB1-ANT) failed to detect HIV-1 infections but reacted with all SIVcpz sera, allowing discrimination of SIVcpz from HIV-1 infections. Since most SIVcpz sera cross-reacted with HIV-1 peptides, we next evaluated SIVcpz serum reactivity with rapid tests for HIV-1/2. SIVcpzANT and SIVcpzUS sera reacted with the Sero-strip and Multispot assays. Both tests are sensitive in detecting group M (97 100%, respectively), although Multispot has lower sensitivity for group O detection (67%) than does Sero-strip (100%). The limited volume and time required to perform these assays make them a generic tool for field screening. The env peptide-based assay and rapid tests should allow for the identification of emerging variants of HIV and SIV.     

Immunological analysis of the zinc-binding peptides of surface metalloproteinase (gp63) of Leishmania major.

The surface metalloproteinase, gp63, is highly conserved and immunogenic. A peptide spanning the zinc-binding region of the molecule is immunogenic and can induce protective immunity in mice against Leishmania major infection. We report here that the minimum length of the immunogenic peptide in this region is a heptapeptide, VVTHEMA, corresponding to residues 161-167. Optimal immunogenicity is conferred by a decapeptide, LVTVVTHEMA, corresponding to residues 158 to 167, where H and E are consensus zinc-binding residues. These two residues determine the specificity of the peptide. The next two residues, M and A are necessary for the immunogenicity of the peptide. These results suggest that the zinc-binding residues are recognized by the T-cell receptor complex, while the two adjacent residues are involved in the peptide presentation by the major histocompatibility complex (MHC) molecule.     

The distribution of fetal nuchal translucency thickness in normal Korean fetuses

The aim of present study was to establish normative data for the distribution of nuchal translucency (NT) thickness in normal Korean fetuses. The data were collected from pregnant women with singleton pregnancies in whom fetal ultrasound was performed and the fetal NT thickness was measured between 11 and 14 weeks of gestation. Among them, a total of 2,577 fetuses with a known normal outcome were included in this study. The distribution of multiple of median (MoM) values of the NT thickness with crown-rump length (CRL) in 10-mm intervals and the 95th percentile of MoM were calculated with the linear regression method. The present study showed that NT measurements increase with increasing CRL and a false positive rate increases with increasing gestational age. Therefore, a fixed cut-off point through the first trimester was not appropriate and each NT measurement should be examined according to the gestational age. The present study offers normative data of the fetal NT thickness in a Korean population, which can be used as reference for screening chromosomal aberrations or other congenital abnormalities in the first trimester.