Oligosaccharide model of the vascular endothelial glycocalyx in physiological flow

Experiments have consistently revealed the pivotal role of the endothelial glycocalyx layer in vasoregulation and the layer’s contribution to mechanotransduction pathways. However, the exact mechanism by which the glycocalyx mediates fluid shear stress remains elusive. This study employs atomic-scale molecular simulations with the aim of investigating the conformational and orientation properties of highly flexible oligosaccharide components of the glycocalyx and their suitability as transduction molecules under hydrodynamic loading. Fluid flow was shown to have nearly no effect on the conformation populations explored by the oligosaccharide, in comparison with static (diffusion) conditions. However, the glycan exhibited a significant orientation change, when compared to simple diffusion, aligning itself with the flow direction. It is the tethered end of the glycan, an asparagine amino acid, which experienced conformational changes as a result of this flow-induced bias. Our results suggest that shear flow through the layer can have an impact on the conformational properties of saccharide-decorated transmembrane proteins, thus acting as a mechanosensor.     

Surface states in electroluminescent MIS diodes of zinc selenide

Measurements of the shunt conductance of electroluminescent MIS diodes of zinc selenide show that the density of surface states in a device in which the metal (gold) electrode was deposited on an etched surface, was of the order of 4 × 10¹¹ cm^?2 eV^?1. When the gold was evaporated on to cleaved surfaces the surface state density was reduced to about 5 × 10¹⁰ cm^?2 eV^?1. The low density of surface states means that donor densities calculated in the normal way from standard C–V measurements are only 6% too high if the measurements are made at 100 kHz and 2% too high if 200 kHz is used.     

Telomerase activity and telomere lengths in various cell lines: changes of telomerase activity can be another method for chemosensitivity evaluation

For the cancer cells which have overcome the second mitotic clock (M2), activated telomerase is essential and used as another marker of immortality. Many trials had been initiated to target telomerase, which is known to be specific to tumors. To determine the best in vitro cell system for testing the efficacy of telomerase inhibitors, we evaluated the telomerase activity of various cancer cell lines and measured their telomere lengths. We also treated some cancer cell lines with adriamycin and measured the changes of telomerase activity. Telomerase activity was evaluated in various cell lines with the TRAP (telomeric repeat amplification protocol) assay. Telomerase activity was calculated and translated into arbitrary units by computer-assisted densitometry with the control of telomerase activity in the 293 control cell line. Also, terminal restriction fragment lengths were measured using Southern blotting. We also measured telomerase activity and telomere lengths in 11 benign breast tumor tissues and 19 paired stomach cancer and normal tissues. Cancer cell lines treated with adriamycin we evaluated for changes of telomerase activity and the cell proliferation by MTT assay and dye exclusion test. Telomerase activity of cell lines was 95.3 24.1 unit with a range of 27.6-129.6 unit, while the telomere lengths of those cell lines were variable from 5.0 to 10.4 kbp with a median of 6 kbp. In 11 cancer cell lines which were not yet firmly established, we could not detect any telomerase activity. Low telomerase activity was detected in only 2 benign tumor tissues of breast with a median telomere length of 8.8 (7-10.5) kbp. Among paired 19 gastric cancer and normal tissues, only 7 cancer tissues showed weak telomerase activity. After adriamycin treatment, telomerase activity in YCC-S-1, YCC-S-3, MCF-7 and MCF-7/ADR was decreased in accordance with the changes of the cell numbers. Telomerase is specific to cancer tissues and is expressed differently from organ to organ. Telomerase activity by TRAP assay could be used as a chemosensitivity assay.     

Adverse consequences of prenatal illicit drug exposure

Our appreciation of the impact on health of illicit drug use is growing. Once considered a maternal risk, prenatal drug exposure may target fetal neurobehavior, affecting attention and learning as the child grows into adulthood. Cocaine, opiates, marijuana, and amphetamines have each been scrutinized for adverse actions on placental transport, fetal behavior states, newborn withdrawal, and childhood learning and attentive skills. Neurotransmitter analysis in the animal model after prenatal drug exposure now provides biological support for these clinical findings. The increasing prevalence of drug use by pregnant women, the effect of illicit drug use on transmission of the human immunodeficiency virus, and the maternal and fetal consequences of illicit drug exposure make illicit drug use in pregnancy a central challenge in maternal-fetal medicine and a need-to-know field in general obstetrics.     

The association rate constant for heme binding to globin is independent of protein structure

Rate constants for CO-heme binding to 35 different recombinant apomyoglobins and several other apoproteins were measured in an effort to understand the factors governing heme affinity and the velocity of the association reaction. Surprisingly, the rate constant for the binding of monomeric heme is approximately 1 x 10(8) M-1 s-1 regardless of the structure or overall affinity of the apoprotein for iron-porphyrin. Major differences between the proteins are reflected primarily in the rates of dissociation of the prosthetic group. Slow phases observed in the reaction of CO heme with excess apomyoglobin result from formation of nonspecific heme-protein complexes which must dissociate before heme can bind specifically in the heme pocket. Once the specific heme-globin complex is formed, the heme pocket rapidly collapses around the porphyrin, simultaneously forming the bond between the proximal His93 and the heme iron atom. The overall affinity of sperm whale apomyoglobin for hemin is approximately 1 x 10(14) M-1. Nonspecific hydrophobic interactions between the porphyrin and the apolar heme cavity account for a factor of 10(5)-10(7). Covalent bond formation between Fe3+ and His93(F8) provides an additional factor of 10(3)-10(4). Specific interactions with conserved amino acids in the heme pocket contribute the final factor of 10(3)-10(4).     

Working Group Report 2: In situ caries models, saliva, microbiology, and statistical considerations

We present a case of a single coronary artery where the right coronary artery (RCA) arose from its proximal part. This rare anomaly was detected during elective coronary angiography in a patient with suspected coronary artery disease. The single coronary artery originated from the left sinus of valsalva, giving rise to RCA proximally and distally dividing into left anterior descending (LAD), ramus intermedius and left circumflex (LCX) arteries. The anginal symptoms in this patient was attributed to a significant stenosis at the proximal LAD which was subsequently dilated by coronary angioplasty. To the best of our knowledge, this is the first reported case of angioplasty of LAD in an anomalous single coronary artery.     

Monoclonal antibodies recognizing epitopes on the extracellular face and intracellular N-terminus of the human erythrocyte anion transporter (band 3) and their application to the analysis of South East Asian ovalocytes

This report describes the production and characterization of 13 rodent monoclonal antibodies to the human erythrocyte anion transport protein AE1 (syn. band 3). Eleven antibodies (4 murine and 7 rat) recognize epitopes dependent on the integrity of the third extracellular loop of the protein. Two antibodies (1 murine and 1 rat) recognize epitopes on the N-terminal cytoplasmic domain. Quantitative binding studies using radioiodinated IgG and Fab fragments of antibodies to extracellular epitopes on AE1 ranged from 77,000 to 313,000 (IgG) and from 241,000 to 772,000 (Fab) molecules bound at saturation. The results indicate that the epitopes recognized by different antibodies vary in their accessibility and suggest that there is heterogeneity in the organization of individual AE1 molecules in the red blood cell membrane. Quantitative binding studies on South East Asian ovalocytes using several antibodies to AE1 and an anti-Wrb show a marked reduction in the number of antibody molecules bound at saturation. These results are consistent with the existence of highly cooperative interactions between transmembrane domains of AE1 in normal erythrocytes and the disruption of these interactions in the variant AE1 found in South East Asian ovalocytes.     

Clinical trial designs--made to order

At times, clinical trial design presents difficult problems for the consulting statistician. The nature of the disease under study or the inadequacies of standard methodology often suggest alternative strategies for the development of useful clinical trial designs. This paper examines two case of novel clinical trial designs that are "made-to-order" for the problem at hand. Both address disease-specific issues. The first case considers the use of adaptive allocation of treatments to patients in a trial in major depressive disorder. The second case reviews the design of a novel efficacy parameter in advanced pancreatic cancer.     

Microvascular transplantation in the salvage of lower extremity trauma in the elderly

In the cadaver of an 86 year old man the inferior segment of the azygos vein could not be found. Furthermore, a normally developed hemiazygos vein drained the right and left intercostal veins from T 10 to T 6. This vessel finally curved towards the right to reach the superior vena cava after having drained the right superior intercostal veins. The left superior intercostal vein ended in a short vessel draining into the left brachiocephalic vein. This condition may be represented in a standard chest radiograph by the so-called "aortic nipple". Agenesis of the azygos vein, suspected because of the presence of this radiological sign, should be confirmed in the living by means of computerized tomography. This can clarify the anatomy of the mediastinal vessels precisely. Embryological pattern of the azygos system accounting for its possible defects is discussed.