[Progress in filters for denoising cryo-electron microscopy images].

Cryo-electron microscopy (cryo-EM) imaging has the unique potential to bridge the gap between cellular and molecular biology. Therefore, cryo-EM three-dimensional (3D) reconstruction has been rapidly developed in recent several years and applied widely in life science research to reveal the structures of large macromolecular assemblies and cellular complexes, which is critical to understanding their functions at all scales. Although the technical breakthrough in recent years, for example, the introduction of the direct detection device (DDD) camera and the development of cryo-EM software tools, made the three cryo-EM pioneers share the 2017 Nobel Prize, several bottleneck problems still exist that hamper the further increase of the resolution of single-particle reconstruction and hold back the application of in situ subnanometer structure determination by cryo-tomography. Radiation damage is still the key limiting factor in cryo-EM. In order to minimize the radiation damage and preserve as much resolution as possible, the imaging conditions of a low dose and weak contrast make cryo-EM images extremely noisy with very low signal-to-noise ratios (SNR), generally about 0.1. The high noise will obscure the fine details in cryo-EM images or reconstructed maps. Thus, a method to reduce the level of noise and improve the resolution has become an important issue. In this paper, we systematically reviewed and compared some robust filters in the cryo-EM field of two aspects, single-particle analysis (SPA) and cryo-electron tomography (cryo-ET), and especially studied their applications, such as, 3D reconstruction, visualization, structural analysis, and interpretation. Conventional approaches to noise reduction in cryo-EM imaging include the use of Gaussian, median, and bilateral filters, among other means. A Gaussian filter selects an appropriate filter kernel to conduct spatial convolution with a noisy image. Although noise with larger standard deviations in cryo-EM images can be suppressed and satisfactory performance is achieved in certain cases, this filter also blurs the images and over-smooths small-scale image features. This is especially detrimental when precise quantitative information needs to be extracted. Unlike a Gaussian filter, a median filter is based on the order statistics of the image and selects the median intensity in a window of the adjacent pixels to denoise the image. Although this filter is robust to outliers, it suffers from aliasing problems that possibly result in incorrect information for cryo-EM structure interpretation. A bilateral filter is a nonlinear filter that performs spatial weighted averaging and is more selective in the pixels allowing to contribute to the weighted sum, excluding the high frequency noise from the smoothing process. Thus, this filter can be used to smooth out noise while maintaining the edge details, which is similar to an anisotropic diffusion filter, and distinct from a Gaussian filter but its utility will be limited when the SNR of a cryo-EM image is very low. Generally, spatial filtering methods have the disadvantage of losing image resolution when reducing noise. A wavelet transform can exploit the wavelet's natural ability to separate a signal from noise at multiple image scales to allow for joint resolution in both the spatial and frequency domains, and thus has the potential to outperform existing methods. The modified wavelet shrinkage filter we developed can offer a remarkable improvement in image quality with a good compromise between detail preservation and noise smoothing. We expect that our review study on different filters can provide benefits to cryo-EM applications and the interpretation of biological structures.

Clinical study of tirofiban compared to low molecular weight heparin in the antithrombotic treatment of progressive pontine infarction.

OBJECTIVE: To investigate the efficacy and safety of tirofiban and low molecular weight heparin (LMWH) in the treatment of patients undergoing acute progressive pontine infarction. PATIENTS AND METHODS: Patients with acute progressive pontine infarction who were hospitalized in the Neurology Department from June 2021 to June 2023 were included in the study and randomly divided into two groups, namely the experimental group (tirofiban group) and the control group (LMWH group). All patients in both groups were required to receive conventional comprehensive treatment and dual antiplatelet therapy with aspirin + clopidogrel at the beginning of admission. The National Institutes of Health Stroke Scale (NIHSS) score and Barthel Index (BI) were used to evaluate the neurological deficits on the first day of admission, the next day with stroke progression, and at discharge after treatment with tirofiban and LMWH, respectively in the two groups. The modified Rankin Scale was employed to assess prognosis on the 90th day after treatment. Clinical adverse events were followed up for 90 days, comparing the clinical efficacy and safety of the two treatment methods. RESULTS: There was no statistical significance in NIHSS score and Barthel Index between the tirofiban group and the LMWH group on the first day of admission and the next day with stroke progression (p > 0.05). After stroke progression, tirofiban and LMWH were separately used for treatment in the two groups. We found that the NIHSS score of the tirofiban group was lower than that of the LMWH group, and the Barthel Index score was higher than that of the LMWH group at discharge (p < 0.05). After three months of follow-up, the mRS score of the tirofiban group was dramatically higher than that of the LMWH group (p < 0.05). No significant harmful or adverse reactions, such as bleeding events, were found in the two groups (p > 0.05). CONCLUSIONS: Tirofiban may be more effective and safer than LMWH in controlling the progression of acute pontine infarction, but further and large-sample studies are still needed to confirm this finding.

Expression profile of macrophage migration-inhibitory factor in human gingiva and reconstituted human gingival epithelia stimulated by Porphyromonas gingivalis lipopolysaccharide.

BACKGROUND AND OBJECTIVE: Macrophage migration-inhibitory factor (MIF) plays crucial roles in the recruitment and activation of macrophages as well as in helping to kill bacteria. This study investigated the expression profile of MIF in human gingiva under different periodontal conditions and its expression patterns induced by Porphyromonas gingivalis lipopolysaccharide (LPS) in gingival epithelia. MATERIAL AND METHODS: Gingival tissue samples were collected from deep pockets and clinically healthy sites of 22 nonsmoking subjects with chronic periodontitis. The expression of MIF mRNA and protein was evaluated using real-time PCR and immunohistochemistry, respectively. The in vitro study analyzed the effects of P. gingivalis LPS on the expression of MIF in a reconstituted human gingival epithelia (RHGE) model. RESULTS: In gingival epithelia, MIF protein was diffusely expressed from the basal layer to the granular and spinous layers; whereas, in the underlying connective tissues, MIF was observed around the dilated blood vessels in the deep-pocket tissues. A significantly lower level of expression of MIF mRNA and an increased level of expression of MIF protein were found in deep-pocket tissues compared with clinically healthy tissues. Expression of MIF mRNA in the RHGE model was significantly down-regulated by P. gingivalis LPS. CONCLUSION: The present study suggests that MIF expression may be related to periodontal conditions and that its expression profile could be modulated by P. gingivalis LPS. MIF may play a role in periodontal pathogenesis.

[Epidemiological characteristics and analysis of related infection risk factors for influenza in Anhui Province from 2013 to 2021].

Objective: Analysis of the characteristics of influenza epidemic in Anhui Province and quantification of the impact of different factors on influenza occurrence, providing scientific basis for better influenza prevention and control. Methods: Descriptive analysis and factor analysis were conducted on influenza-like illness (ILI) cases and RT-PCR results in Anhui Province from 2013 to 2021 using data from China's Influenza Monitoring Information System. Results: The percentage of influenza-like illness (ILI%) of sentinel hospitals in Anhui Province from April 1, 2013 to March 31, 2021 was 3.80% (1 209 142/31 779 987), showing an overall increasing trend, with a relatively high proportion in 2017-2018 at 4.30% (191 148/4 448 211). The proportion of ILI cases in infants and young children aged 0-4 years was a relatively high at 54.14% (654 676/1 209 142), and the highest ILI% was observed in Fuyang City, Anhui Province (6.25%, 236 863/3 788 863). Laboratory monitoring results showed that the positive rate of ILI cases in sentinel hospitals in 8 influenza monitoring years was 16.38% (34 868/212 912), showing an increasing trend year by year, with a relatively proportion in 2017-2018 at 26.19% (6 936/26 488). The detection rate of school-age children aged 5-14 years was a relativelyhigh at 28.81% (13 869/48 144), and the positive rate was a relatively high in Wuhu City among the 16 cities, reaching 22.01% (2 693/122 237). Influenza activity showed a single peak in winter-spring and alternating double peaks in winter-spring and summer, with different subtypes alternating, and A (H3N2) was the dominant subtype in summer. The results of a multiple logistic regression model showed that the positive rate was higher in 2017-2018, among children aged 5-14 years, in winter, and in southern Anhui. Conclusions: Influenza epidemic in Anhui Province has a clear seasonal pattern, and the ILI% and detection rate have shown an upward trend from 2013 to 2021. Therefore, it is suggested to ensure vaccine supply before the winter-spring influenza season arrives, and to strengthen vaccine uptake and health education to avoid the risk of infection during the peak period of influenza.

Kidney-targeting Smad7 gene transfer inhibits renal TGF-ß/MAD homologue (SMAD) and nuclear factor κB (NF-κB) signalling pathways, and improves diabetic nephropathy in mice.

AIMS/HYPOTHESIS: The TGF-ß/MAD homologue (SMAD) and nuclear factor κB (NF-κB) signalling pathways have been shown to play a critical role in the development of renal fibrosis and inflammation in diabetic nephropathy. We therefore examined whether targeting these pathways by a kidney-targeting Smad7 gene transfer has therapeutic effects on renal lesions in the db/db mouse model of type 2 diabetes. METHODS: We delivered Smad7 plasmids into the kidney of db/db mice using kidney-targeting, ultrasound-mediated, microbubble-inducible gene transfer. The histopathology, ultrastructural pathology and pathways of TGF-ß/SMAD2/3-mediated fibrosis and NF-κB-dependent inflammation were evaluated. RESULTS: In this mouse model of type 2 diabetes, Smad7 gene therapy significantly inhibited diabetic kidney injury, compared with mice treated with empty vectors. Symptoms inhibited included: (1) proteinuria and renal function impairment; (2) renal fibrosis such as glomerular sclerosis, tubulo-interstitial collagen matrix abundance and renal inflammation, including Inos (also known as Nos2), Il1b and Mcp1 (also known as Ccl2) upregulation, as well as macrophage infiltration; and (3) podocyte and endothelial cell injury as demonstrated by immunohistochemistry and/or electron microscopy. Further study demonstrated that the improvement of type 2 diabetic kidney injury by overexpression of Smad7 was associated with significantly inhibited local activation of the TGF-ß/SMAD and NF-κB signalling pathways in the kidney. CONCLUSIONS/INTERPRETATION: Our results clearly demonstrate that kidney-targeting Smad7 gene transfer may be an effective therapy for type 2 diabetic nephropathy, acting via simultaneous modulation of the TGF-ß/SMAD and NF-κB signalling pathways.

Multicavity x-ray Fabry-Perot resonance with ultrahigh resolution and contrast.

Realization of x-ray Fabry-Perot (FP) resonance in back-Bragg-reflection crystal cavities has been proposed and explored for many years, but to date no satisfactory performance has been achieved. Here we show that single-cavity crystal resonators intrinsically have limited finesse and efficiency. To break this limit, we demonstrate that monolithic multicavity resonators with equal-width cavities and specific plate thickness ratios can generate ultrahigh-resolution FP resonance with high efficiency, steep peak tails, and ultrahigh contrast simultaneously. The resonance mechanism is similar to that of sequentially cascaded single-cavity resonators. The ultranarrow-bandwidth FP resonance is anticipated to have various applications, including modern ultrahigh-resolution or precision x-ray monochromatization, spectroscopy, coherence purification, coherent diffraction, phase contrast imaging, etc.

C-reactive protein promotes diabetic kidney disease in a mouse model of type 1 diabetes.

AIMS/HYPOTHESIS: Although C-reactive protein (CRP) has been implicated as a risk factor in diabetes, its pathogenic importance in diabetic kidney disease (DKD) remains unclear. The present study investigated the potential role of CRP in DKD. METHODS: Diabetes was induced by streptozotocin in human CRP transgenic and wild-type mice for assessment of kidney injury at 24 weeks by real-time PCR, immunohistochemistry and western blot analysis. In vitro, the pathogenic effect of CRP was investigated using human kidney tubular epithelial cells cultured with high glucose and/or CRP. RESULTS: We found that CRP transgenic mice developed much more severe diabetic kidney injury than wild-type mice, as indicated by a significant increase in urinary albumin excretion and kidney injury molecule-1 abundance, enhanced infiltration of macrophages and T cells, and upregulation of pro-inflammatory cytokines (IL-1ß, TNFα) and extracellular matrix (collagen I, III and IV). Enhanced renal inflammation and fibrosis in CRP transgenic mice was associated with upregulation of CRP receptor, CD32a, and over-activation of the TGF-ß/SMAD and nuclear factor κB signalling pathways. In vitro, CRP significantly upregulated pro-inflammatory cytokines (IL-1ß, TNFα, monocyte chemoattractant protein-1 [MCP-1]) and pro-fibrotic growth factors (TGF-ß1, connective tissue growth factor [CTGF]) via CD32a/64. CRP was induced by high glucose, which synergistically promoted high glucose-mediated renal inflammation and fibrosis. CONCLUSIONS/INTERPRETATION: CRP is not only a biomarker, but also a mediator in DKD. Enhanced activation of TGF-ß/SMAD and nuclear factor κB signalling pathways may be the mechanisms by which CRP promotes renal inflammation and fibrosis under diabetic conditions.

Detailed diffraction imaging of x-ray optics crystals with synchrotron radiation.

Rocking curve topography at the Advanced Photon Source's beamline 1-BM measures the x-ray reflection from large (many cm2) flat crystals on a sub-mm scale with microradian angular resolution. The (011̄1) reflection at 8 keV is uniform across the crystal and close to theory for three thick quartz wafers well-polished with increasingly finer grit. However, the reflection is non-uniform for some ∼0.1 mm thin, bendable crystals that are made flat by optical contact with a flat substrate. These thin crystals are bent to serve in certain x-ray diagnostics of plasmas, and similar non-uniformities could then occur in bent crystals as well. The same detail in x-ray reflection in bent crystals is unachievable with the existing topography setup: One way to get the desired resolution is with a standard microfocusing approach.

MicroRNA-204 targets SOX4 to inhibit metastasis of lung adenocarcinoma.

OBJECTIVE: The dysregulation of microRNAs (miRNAs) has been found in human cancers. In this study, the functions of miR-204 and SOX4 (sex-determining region Y-box 4) and their interaction on lung adenocarcinoma cell metastasis and epithelial-mesenchymal transition (EMT) were investigated. PATIENTS AND METHODS: MiR-204 and SOX4 expressions were examined via quantitative Real-time polymerase chain reaction (qRT-PCR) in lung adenocarcinoma. Western blot was used to detect the expressions of SOX4 and EMT markers. The relationship between miR-204 and SOX4 was verified by a dual-luciferase reporter assay. Transwell assay was utilized to explore the functions of miR-204 and SOX4 associated with lung adenocarcinoma metastasis. RESULTS: First, downregulation of miR-204 was examined in lung adenocarcinoma tissues. Moreover, overexpression of miR-204 inhibited metastasis and EMT of lung adenocarcinoma cells. In addition, SOX4 has been shown to be a direct target of miR-204 in lung adenocarcinoma. SOX4 silencing suppressed cell metastasis and EMT in lung adenocarcinoma. And the upregulation of SOX4 impaired the inhibitory effect of miR-204 on lung adenocarcinoma metastasis. CONCLUSIONS: MiR-204 inhibited cell metastasis and EMT in lung adenocarcinoma through targeting SOX4.

The miR-224 promotes non-small cell lung cancer cell proliferation by directly targeting RASSF8.

OBJECTIVE: The purpose of this study was to explore the mechanism of microRNA-224 (miR-224) in NSCLC. PATIENTS AND METHODS: Quantitative RT-PCR (qRT-PCR) was used to evaluate expression levels of miR-224. The association of miR-224 with the clinicopathologic features of NSCLC was evaluated in 56 patients. The roles of miR-224 in cell proliferation were analyzed in vivo and in vitro with pre-miR-224 transfected cells. Also, the regulation of RASSF8 by miR-224 was evaluated by qRT-PCR, Western blotting and luciferase reporter assays. RESULTS: In this study, we identified miR-224 to be significantly up-regulated in NSCLC tissues and associated with tumor size. Increased miR-224 expression promotes NSCLC cell proliferation by down-regulating RASSF8 at the mRNA and protein levels. The AKT pathway was found aberrantly activated after over-expression of miR-224. RASSF8 was identified as a direct target of miR-224 by bioinformatics analysis and luciferase reporter assay. CONCLUSIONS: The miR-224 played an oncogenic role in the proliferation of NSCLC by direct targeting RASSF8, and it is suggested that miR-224 may be a potential therapeutic target for NSCLC.

De novo expression of macrophage migration inhibitory factor in atherogenesis in rabbits.

Macrophage migration inhibitory factor (MIF) has been shown to play an important role in macrophage-mediated diseases. We investigate the potential role of MIF in atherogenesis using a hypercholesterolemic rabbit model. New Zealand White rabbits fed with a 2% cholesterol diet developed hypercholesterolemia and early fatty streaks at 1 month. The lesions became advanced at 3 months and were associated with de novo MIF expression by vascular endothelial cells (VECs) and smooth muscle cells (SMCs), as demonstrated by immunohistochemistry, reverse transcriptase-polymerase chain reaction, and in situ hybridization. By contrast, there was no increase in MIF levels in rabbits fed a normal diet. In early atherogenesis, marked upregulation of MIF mRNA and protein by VECs and some intimal cells were closely associated with CD68(+) monocyte adhesion onto and subsequent migration into subendothelial space. Of significance, the accumulation of macrophages was exclusively localized to areas of strong MIF expression, which may be associated with the macrophage-rich fatty streak lesion formation. Upregulation of MIF by SMCs is transient during atherogenesis. Importantly, strong MIF expression by activated macrophages may be responsible for the development of foam cell-rich lesions. Finally, the ability of MIF to induce intercellular adhesion molecule-1 expression by VECs implicates its pathogenic role in atherogenesis. In conclusion, the present study provides the first demonstration that MIF is markedly upregulated during atherogenesis. Upregulation of MIF by VECs and SMCs may play a role in macrophage adhesion, transendothelial migration, accumulation, and, importantly, transformation into foam cells. Furthermore, strong MIF expression by macrophages may both initiate and amplify the atherogenesis process.

Polarization properties of the retinal nerve fiber layer.

Recently developed optical techniques provide quantitative structural measurements of the retinal nerve fiber layer (RNFL). A complete interpretation of these measurements requires understanding of the optical properties of the RNFL. This paper gives a review of the polarization properties and relevant anatomy of the ocular tissues, followed by a thorough discussion of the optical properties of the RNFL. The RNFL reflectance arises from light scattering from cylinders. Microtubules are a major component contributing to the reflectance. The RNFL reflectance exhibits weak intrinsic diattenuation and well preserves polarization. RNFL birefringence varies across the retina; the variation suggests that birefringence depends on the ultrastructure of the nerve fiber bundles, which offers hope that measurement of RNFL birefringence may be able to provide early detection of subcellular changes in glaucoma.

[Investigate the expression of miRNA-203 in papillary thyroid carcinomaand its effect on cell proliferation].

Objective:To investigate the expression of miRNA-203 in papillary thyroid carcinoma（PTC）tissues and its correlation with clinical pathological parameters，explore its effect on cell proliferation of WRO cell. Method:Thirty cases of PTC tissues, paired normal tissues were collected in our hospital during 2013-2016. The expression of miRNA-203 was determined by qRT-PCR，then the relationship of miRNA-203 expression, clinical pathological parameters were analyzed.WRO cells were transfected with miRNA-203 mimics, then cell proliferation, cell cycle and concerned cyclin protein(CyD1,CyB1) were tested by MTT, flow cytometry and western blot. Result:Compared to the paired normal tissues，tumor tissues showed sifnificantly lower expression of miRNA-203. Upregulaion of miRNA-203 in WRO cells effectively reduced cell growth, G2/M arrest. Mechanistically,in the miRNA-203-mimics-treated groups,cell-cycle-related proteins cyclin B1 was up-regulated, while cyclin D1 was down-regulated. Conclusion:miRNA-203 may play an anticarcinogenic effect in PTC. Upregulation of miRNA-203 is highly correlated with cell prolliferation, and maybe miRNA-203 is a potential targert for the treatment of thyroid carcinoma.

Directional and spectral reflectance of the rat retinal nerve fiber layer.

PURPOSE: To measure and describe the reflectance properties of a mammalian retinal nerve fiber layer (RNFL) and to determine the mechanisms responsible for the RNFL reflectance. METHODS: An isolated rat retina suspended across a slit in a black membrane and mounted in a black perfusion chamber provided high quality images of the RNFL. Imaging microreflectometry was used to measure RNFL reflectance at wavelengths from 400 nm to 830 nm and as a function of illumination angle. RESULTS: The directional reflectance of rat RNFL at all wavelengths was consistent with the theory of light scattering by cylinders; each nerve fiber bundle scattered light into a conical sheet coaxial with the bundle. There was no evidence of a noncylindrical component at any wavelength. Measured reflectance spectra were consistent between animals, similar to ones previously measured in macaque, and varied with scattering angle. All spectra could be described by a two-mechanism cylindrical scattering model with three free parameters. CONCLUSIONS: At all wavelengths the reflectance of rat RNFL arises from light scattering by cylindrical structures. The highly directional nature of this reflectance can be an important source of measurement variability in clinical assessment of the RNFL. The reflectance spectra reveal a combination of mechanisms: At wavelengths shorter than approximately 570 nm the reflectance comes from cylinders with diameters much smaller than the wavelength, but at wavelengths longer than approximately 680 nm the reflectance comes from cylinders with effective diameters of 350 nm to 900 nm.

Interleukin-1 induces tubular epithelial-myofibroblast transdifferentiation through a transforming growth factor-beta1-dependent mechanism in vitro.

Interleukin-1 (IL-1) has been shown to exert profibrotic activity in a number of disease models, including crescentic glomerulonephritis and pulmonary fibrosis, but the mechanisms by which this operates are poorly understood. Recent studies have identified a novel mechanism promoting renal fibrosis: tubular epithelial-myofibroblast transdifferentiation (TEMT). The present study examined whether IL-1 can stimulate TEMT in vitro. Cells of the normal rat kidney tubular epithelial cell line (NRK52E) were grown to confluence on collagen-coated plates and cultured for 5 days in the presence 1 to 20 ng/mL of IL-1alpha. Doses of 10 to 20 ng/mL of IL-1 caused transdifferentiation of NRK52E cells into myofibroblast-like cells. Scanning electron microscopy identified IL-1-induced morphological changes as a loss of apical-basal polarity and microvilli, cell hypertrophy, and the development of an elongated and invasive appearance. Phenotypically, IL-1-induced TEMT was characterized by de novo messenger RNA and protein expression of the mesenchymal marker alpha-smooth muscle actin, shown by Northern blotting, immunohistochemistry, and Western blotting. This was accompanied by loss of the epithelial marker E-cadherin. The addition of an excess of IL-1-receptor antagonist completely inhibited IL-1-induced TEMT. IL-1 was shown to stimulate the secretion of active transforming growth factor-beta1 (TGF-beta1) by NRK52E cells. Furthermore, the addition of a neutralizing anti-TGF-beta1 antibody inhibited IL-1-induced TEMT. In conclusion, IL-1 is a profibrogenic cytokine capable of inducing TEMT through a TGF-beta1-dependent mechanism. This may represent a novel mechanism by which IL-1 induces renal fibrosis in vivo.

Tubular phenotypic change in progressive tubulointerstitial fibrosis in human glomerulonephritis.

There is much debate over the origins of fibroblast-type cells that accumulate in interstitial fibrosis. A controversial hypothesis, supported by data from animal and cell-culture studies, is that fibroblast-type cells can derive from tubular epithelial cells by a process of epithelial-mesenchymal transdifferentiation. However, to date, no evidence supports this postulate in human glomerulonephritis. This study sought to provide evidence that tubular epithelial cells can undergo phenotypic change toward a fibroblast-like cell in human glomerulonephritis. One hundred twenty-seven open renal biopsy specimens from patients with minimal change disease (MCD), immunoglobulin A (IgA) nephropathy, and rapidly progressive glomerulonephritis (RPGN) were examined for tubular phenotypic change by two-color immunohistochemistry using the criteria of de novo expression of alpha-smooth muscle actin (alpha-SMA), a myofibroblast marker; loss of the epithelial marker cytokeratin; and collagen production. In normal human kidney and MCD, tubular epithelial cells expressed cytokeratin with no evidence of alpha-SMA staining. However, in 36 of 90 cases of IgA nephropathy and 9 of 18 cases of RPGN, small numbers of tubular epithelial cells in areas of fibrosis showed de novo alpha-SMA expression, accounting for 0.4% +/- 0.2% (IgA nephropathy) and 3.8% +/- 1.5% (RPGN) of cortical tubules. An intermediate stage of phenotypic change was observed in some cuboidal epithelial cells that expressed both cytokeratin and alpha-SMA. Tubules containing alpha-SMA-positive (alpha-SMA(+)) cells also stained for collagen types I and III, suggesting that tubular cells undergoing phenotypic change have an active role in the fibrotic process. There also was a marked increase in transforming growth factor-beta1 (TGF-beta1) tubular expression in areas with interstitial fibrosis, including tubules with phenotypic change. There was a highly significant correlation between tubular alpha-SMA expression and interstitial fibrosis, interstitial alpha-SMA(+) myofibroblast accumulation, deposition of collagen types I and III, tubular TGF-beta1 expression, and renal dysfunction. In conclusion, this study provides evidence that tubular epithelial cells can undergo phenotypic change toward a myofibroblast-like phenotype on the basis of de novo alpha-SMA expression, loss of cytokeratin, and de novo collagen staining. These data, although not conclusive, provide the first support for the hypothesis that transdifferentiation of tubular epithelial cells has a role in progressive renal fibrosis in human glomerulonephritis.

Macrophage migratory inhibitory factor (MIF) expression in acute graft-versus-host disease (GVHD) in allogeneic hemopoietic stem cell transplant recipients.

Graft-versus-host disease (GVHD) is a major complication after hemopoietic stem cell transplantation (HSCT), but its pathogenesis remains uncertain. Macrophage migratory inhibitory factor (MIF) is an important mediator in the allo-immune reaction during renal transplantation, yet its role in hemopoietic stem cell transplantation (HSCT) remains unexplored. This study investigated the potential role of MIF in acute graft-versus-host disease (aGVHD) following allogeneic HSCT. Forty-six randomly selected patients undergoing autologous or allogeneic HSCT were studied. Immunohistochemistry and in situ hybridization were performed to examine tissue MIF mRNA and protein expression on skin and colonic biopsy specimens. The associated T cell and macrophage activation was also studied by immunohistochemical studies. A semi-quantitative method was used to assess MIF staining, as well as T cell and macrophage staining. Serial blood samples were analyzed by ELISA for serum MIF levels. Immunohistochemistry and in situ hybridization performed in 15 skin and 19 colonic biopsies from 17 patients who developed moderate to severe aGVHD showed a significant increase in MIF mRNA and protein expression compared with normal controls (seven skin and five colonic biopsies). MIF was localized within the epidermis and the vascular area of skin, but diffusely expressed in the entire thickness of colon. Macrophage and T lymphocyte infiltration was confined to areas of strong MIF expression. Serial analysis by ELISA showed that only patients who developed aGVHD (n = 19) exhibited an increase (two- to three-fold) in serum MIF during HSCT, but not in the allogeneic HSCT recipients without aGVHD (n = 7) or those who received autologous HSCT (n = 8). In 14 out of 19 patients, serum MIF peaked before the onset of aGVHD. Local and systemic up-regulation of MIF expression is associated with the occurrence of acute GVHD. Its pathogenetic role remains to be further determined.

Effect of corneal polarization axis on assessment of retinal nerve fiber layer thickness by scanning laser polarimetry.

PURPOSE: Scanning laser polarimetry uses an anterior segment compensating device that assumes a fixed axis of corneal birefringence, which we call the corneal polarization axis. The purpose of this investigation was to establish the distribution of corneal polarization axes among a population of normal eyes and to evaluate the relationship between corneal polarization axis and posterior segment retardation. METHODS: We constructed a noninvasive slit lamp-mounted device incorporating two crossed linear polarizers and an optical retarder in order to measure the slow axis of corneal birefringence. Normal subjects underwent corneal polarization axis measurement. A subset of eyes underwent scanning laser polarimetry of the peripapillary retinal nerve fiber layer (n = 32) and macula (n = 29), and retardation measurements were evaluated in each group. RESULTS: One hundred eighteen eyes of 63 normal subjects (35 female, 28 male) underwent corneal polarization axis measurement (mean age, 45.5 +/- 17.1 years). Six eyes (5.1%) demonstrated unmeasurable corneal polarization. In the remaining 112 eyes, the mode of the corneal polarization axis distribution was 10 to 20 degrees nasally downward (range, 90 degrees nasally downward to 54 degrees nasally upward). A significant (P <.0001) correlation was observed between fellow eyes (R(2) =.52), with a mean difference of 11.2 +/- 10.5 degrees (range, 0-52 degrees). Corneal polarization axis was significantly associated (R(2) =.52-.84) with retinal nerve fiber layer and macula summary retardation parameters (average thickness, ellipse average, superior and inferior average, superior and total integral; P <.0001 for all groups). CONCLUSIONS: The mean corneal polarization axis among normal corneas is nasally downward; however, considerable intraindividual and interindividual variability exists. The linear relationship between corneal polarization axis and posterior segment retardation parameters is responsible, in part, for the wide distribution of retinal nerve fiber layer thickness data generated by scanning laser polarimetry.

Forbidden X-ray wavefields of three-beam Bragg reflections from thick crystals.

A detailed analysis of a three-beam diffraction dispersion surface is performed to study the forbidden wavefields of thick-crystal Bragg reflections. From the asymptotic transition between two- and three-beam diffraction, it is found that the excitation state of each wavefield can be accurately determined with the two-beam criterion. Consequently, Bragg-case three-beam diffraction from thick crystals is either a four-mode diffraction process for the Bragg-Laue geometry or a two-mode process for the Bragg-Bragg geometry, and the amplitudes of the excited wavefields can be completely determined by the entrance boundary conditions. Based on this picture, the intrinsic mechanisms underlying three-beam Bragg reflections are clearly illustrated.