Cell Biochemistry and Biophysics

Patients with rheumatic heart disease (RHD) often experience persistent atrial fibrillation (AF) associated with adverse atrial structural remodeling (ASR) manifested by atrial fibrosis and left atrial enlargement. The aim of this study was to explore the potential molecular signaling mechanisms for atrial fibrosis and ASR. Twenty RHD patients with persistent AF and 10 RHD patients with sinus rhythm (Group A) were recruited in our study, which all underwent transthoracic echocardiography. Right atrial appendage (RAA) tissue samples were obtained from these patients during mitral/aortic valve replacement operation. The AF patients were further divided into two groups according to left atrial diameter (LAD): Group B with LAD ranging 50–65 mm and Group C with LAD >65 mm. Histological examinations were performed with hematoxylin–eosin staining and Masson’s trichrome staining. Atrial angiotensin II (AngII) content was measured by ELISA. Rac1 and STAT3 protein levels were determined by Western blot analysis. Hematoxylin–eosin staining demonstrated highly organized arrangement of atrial muscles in control Group A and significant derangement in both Group B and C AF patients with reduced cell density and increased cell size. Moreover, Masson’s trichrome staining showed that atrial myocytes were surrounded by large trunks of collagen fibers in both Group B and C, but not in Group A. There was a positive correlation between atrial tissue fibrosis and LAD. AngII content was markedly higher in Group C than in Group B than in Group A, which was positively correlated with LAD. Similarly, Rac1 and STAT3 protein levels were found considerably higher in Group C and B than in Group A with excellent correlation to LAD. Our study unraveled for the first time the AngII/Rac1/STAT3 signaling as a mechanism for ASR thereby AF in a particular clinical setting―RHD patients with persistent AF and indicated inhibition of this pathway may help ameliorating adverse ASR.

Head and neck squamous cell carcinoma (HNSCC) tumours are associated with high mortality despite advances in therapy. The monoclonal antibody cetuximab (Erbitux®) has been approved for the treatment of advanced HNSCC. However, only a subset of HNSC patients receiving cetuximab actually responds to treatment, underlining the need for a means to tailor treatments of individual patients. The aim of the present study was to investigate the effect of cetuximab treatment on tumour growth, on tumour partial oxygen pressure as measured by LiPc electron paramagnetic resonance oximetry and on the expression of proteins involved in tumour growth, metabolism and hypoxia. Two HNSCC cell lines, UT-SCC-2 and UT-SCC-14, were used to generate xenografts on female BALB/c (nu/nu) nude mice. Mice with xenografts were given three injections of intraperitoneal cetuximab or phosphate-buffered saline, and the tumour volume was recorded continuously. After treatment the tumour partial oxygen pressure was measured by LiPc electron paramagnetic resonance oximetry and the expression of epidermal growth factor receptor (EGFR), phosphorylated EGFR, Ki-67, MCT1, MCT4, GLUT1, CAIX and HIF-1α were investigated by immunohistochemistry. In xenografts from both cell lines (UT-SCC-2 and UT-SCC-14) cetuximab had effect on the tumour volume but the effect was more pronounced on UT-SCC-14 xenografts. A higher tumour oxygenation was measured in cetuximab-treated tumours from both cell lines compared to untreated controls. Immunocytochemical staining after cetuximab treatment shows a significantly decreased expression of EGFR, pEGFR, Ki67, CAIX and nuclear HIF-1α in UT-SCC-14 tumours compared to untreated controls. MCT1 and GLUT1 were significantly decreased in tumours from both cell lines but more pronounced in UT-SCC-14 tumours. Taken together, our results show that cetuximab treatment decreases the tumour growth and increases the tumour partial oxygen pressure of HNSCC xenografts. Furthermore we found a potential connection between the partial oxygen pressure of the tumours and the expression of proteins involved in tumour growth, metabolism and hypoxia.

Khối u thượng thận hai bên là rất hiếm gặp trong thực hành lâm sàng và tất cả đều xuất phát từ cùng một mô bệnh học. Chúng tôi trình bày ở đây một báo cáo ca bệnh và tổng quan tài liệu về khối u thượng thận hai bên từ các mô bệnh học khác nhau: một bên là u tủy thượng thận và bên còn lại là u tuyến vỏ thượng thận. Bệnh nhân là một nữ 37 tuổi bị hội chứng Cushing trong 3 năm. Một năm trước, cô được chẩn đoán là hội chứng Cushing không phụ thuộc ACTH và đã trải qua phẫu thuật cắt bỏ thượng thận nội soi cho khối u thượng thận bên phải, được chẩn đoán là u tủy thượng thận qua các báo cáo tế bào học. Sau phẫu thuật, triệu chứng lâm sàng của bệnh nhân không thay đổi, sau đó nửa năm sau, xét nghiệm phòng thí nghiệm cho thấy không cải thiện các chỉ số sinh hóa máu. Cuối cùng, CT phát hiện một khối ở tuyến thượng thận trái. Sau đó, bệnh nhân này đã trải qua phẫu thuật cắt bỏ thượng thận nội soi cho khối u thượng thận bên trái. Khối u được chẩn đoán là u tuyến vỏ thượng thận bởi các bác sĩ bệnh lý. Một tuần sau phẫu thuật, các chỉ số sinh hóa máu trở về bình thường. Kết luận, khối u thượng thận hai bên từ các mô bệnh học khác nhau là rất hiếm, cắt bỏ thượng thận cho cả hai khối u và bảo tồn các tuyến thượng thận bình thường là cần thiết.

A simplified theory of image formation in phase contrast microscopy is presented. It is shown that the phase shift induced in light (related to the refractive index) by the observed object can be reconstructed, point by point, from the phase-contrast digitally sampled image through an appropriate algorithm. This allows one to make quantitative observations on unstained, living cells.

In this review we summarize our approach to the study of Intermediate Filament (IF) structure and assembly by electron paramagnetic resonance (EPR) spectroscopy of site-directed spin labels. Using vimentin, a homopolymeric type III IF protein, we demonstrate that this approach serves as a general paradigm for studying protein filament structure and assembly. These strategies will be useful in exploring the structure and assembly properties of other filamentous or aggregation-prone systems.

In this article the authors discuss an indirect system for redirecting cellular cytotoxicity, which utilizes a “universal” bispecific antibody to redirect T-cells to kill cells targeted with single-chain Fv (sFv) fusion proteins that carry a peptide tag recognized by the bispecific antibody. This approach has a number of theoretical advantages in the immunotherapy of cancer.

Using HeLa S-3 cells synchronized by selective detachment, in this paper we report a parallel study of nuclear morphology and autoradiography grain patterns between middle G1 and middle S phases: Our results show two distinct [3H]-thymidine labeling patterns. The first “peripheral” labeling pattern has a characteristic nuclear size distribution, in contrast to the heterogeneous and varying size distributions of Feulgen-stained nuclei, and apparently is characteristic of very early S phase. The sizes of the second labeling pattern—homogeneous or inhomogeneous grain distribution throughout the nucleus—are equal or larger than the first and vary with S phase progression. Together, the corresponding nuclear sizes of the labeled nuclei represent the larger extreme of nuclear areas, and the labeling index closely parallels the fraction of nuclei with areas larger than the minimum size of the labeled nuclei. These results suggest a characteristic nuclear size (reflecting unique intranuclear DNA distribution) as a necessary, if not sufficient, requirement for S phase initiation. Parallel experimentation with rat liver cells—synchronized in vivo by partial hepatectomy and analyzed by thin section autoradiography—confirms the existence of a peripheral labeling pattern in both the very early part and the very late part of S phase, which reconciles our data with previous results and points to the fact that both initiation and termination sites for DNA replication are near the nuclear periphery.

A microscope laser light scattering setup was developed, allowing us to do intensity autocorrelation spectroscopy on the light scattered from a volume as small as (2 μm)3. This non-invasive technique makes cytoplasmic studies possible inside single live biological cells. The effect of osmotic swelling and shrinking on the diffusion coefficient of hemoglobin inside intact red blood cells is shown as an illustrative example of the applicability and sensitivity of this new experimental method.