Hemodynamic effects of red blood cell aggregation

The influence of red blood cell (RBC) aggregation on blood flow in vivo has been under debate since early 1900's, yet a full understanding has still has not been reached. Enhanced RBC aggregation is well known to increase blood viscosity measured in rotational viscometers. However, it has been demonstrated that RBC aggregation may decrease flow resistance in cylindrical tubes, due to the formation of a cell-poor zone near the tube wall which results from the enhanced central accumulation of RBC. There is also extensive discussion regarding the effects of RBC aggregation on in vivo blood flow resistance. Several groups have reported increased microcirculatory flow resistance with enhanced RBC aggregation in experiments that utilized intravital microscopy. Alternatively, whole organ studies revealed that flow resistance may be significantly decreased if RBC aggregation is enhanced. Recently, new techniques have been developed to achieve well-controlled, graded alterations in RBC aggregation without influencing suspending phase properties. Studies using this technique revealed that the effects of RBC aggregation are determined by the degree of aggregation changes, and that this relationship can be explained by different hemodynamic mechanisms.     

Complex coacervation of silk fibroin and hyaluronic acid

This study aimed to investigate the pH-induced complexation of silk fibroin (SF) and hyaluronic acid (HA). SF-HA complex coacervation was investigated by monitoring turbidity of the SF-HA system under slow acidification. Gravimetric analysis was performed to determine the yield of complex coacervation and viscosity of the system was measured to study the formation of the complexes at different pH values. The influences of total biopolymer concentration and biopolymer weight ratio on complex coacervation were examined during the analyses. Formation of the complexes was evidenced by the minimum viscosity and the maximum turbidity observed in the system. SF-HA complexes were formed within the pH-window of 2.5-3.5 regardless of the total biopolymer concentration or biopolymer ratio. Complex coacervation of SF-HA showed a reversible behavior and coacervation could be handled even in excess amounts of the biopolymers, which pointed out a non-stoichiometric complexation.     

An extracellular--pepstatin insensitive acid protease produced by Thermoplasma volcanium

In this study, some parameters for the production and caseinolytic activity of an extracellular thermostable acid protease from a thermoacidophilic archaeon Thermoplasma volcanium were determined. The highest level of growth and enzyme production were detected at pH 3.0 over an incubation period of 192 h at 60 degrees C. The pH optimum for the acid protease activity was 3.0 and the enzyme was fairly stable over a broad pH range (pH 3.0-8.0). The temperature for maximum activity of the enzyme was 55 degrees C and activity remained stable between 50 degrees C and 70 degrees C. These features could be of relevance for various biotechnological applications of this enzyme. Serine-(PMSF), cysteine-(DTT), metallo-(EDTA) and aspartate-(pepstatin) protease inhibitors did not inhibit the caseinolytic activity of the enzyme. Therefore, Tp. volcanium acid protease could be a member of the pepstatin-insensitive carboxyl proteinases.     

MAGEB2 is Activated by Promoter Demethylation in Head and Neck Squamous Cell Carcinoma

Purpose

Although promoter hypermethylation has been an accepted means of tumor suppressor gene inactivation, activation of otherwise normally repressed proto-oncogenes by promoter demethylation has been infrequently documented.

Experimental Design

In this study we performed an integrative, whole-genome analysis for discovery of epigenetically activated proto-oncogenes in head and neck cancer tumors. We used the 47K GeneChip U133 Plus 2.0 Affymetrix expression microarray platform to obtain re-expression data from 5-aza treated normal cell line and expression data from primary head and neck squamous cell carcinoma (HNSCC) tumor tissues and normal mucosa tissues. We then investigated candidate genes by screening promoter regions for CpG islands and bisulfite sequencing followed by QUMSP and RT PCR for the best candidate genes. Finally, functional studies were performed on the top candidate gene.

Results

From the top 178 screened candidates 96 had CpG islands in their promoter region. Seven candidate genes showed promoter region methylation in normal mucosa samples and promoter demethylation in a small cohort of primary HNSCC tissues. We then studied the demethylation of the top 3 candidate genes in an expanded cohort of 76 HNSCC tissue samples and 17 normal mucosa samples. We identified MAGEB2 as having significant promoter demethylation in primary head and neck squamous cell carcinoma tissues. We then found significantly higher expression of MAGEB2 in tumors in a separate cohort of 73 primary HNSCC tissues and 31 normal tissues. Finally, we found that MAGEB2 has growth promoting effects on minimally transformed oral keratinocyte cell lines but not a definite effect on HNSCC cell lines.

Conclusion

In conclusion, we identified MAGEB2 as activated by promoter demethylation in HNSCCand demonstrates growth promoting effects in a minimally transformed oral keratinocyte cell line. More studies are needed to evaluate MAGBE2''s exact role in HNSCC.     

Familial genetic risk factors in premature cardiovascular disease: a family study

Cardiovascular disease (CVD) is closely associated with familial predisposition. The aim of the present study was to investigate predisposing risk factors in the family of a young patient who underwent coronary artery bypass graft surgery due to CVD. The father and uncle of the patient died at an early age due to myocardial infarction. Various stages of CVD were identified in both of the patient’s brothers (28 and 32 years of age). Biochemical tests (fasting blood glucose, lipid profile, urea, creatinine and liver enzymes) and a complete blood count (haemoglobin, haematocrit, white blood cell count, and platelet count) were performed. Physiological coagulation inhibitory factors (protein C, protein S, and antithrombin III), prothrombotic genetic risk factors (factor V Leiden, plasminogen activator inhibitor-1, methylenetetrahydrofolate reductase A1C and C6T, angiotensin-converting enzyme, β-fibrinogen, glycoprotein IIIa and factor XIII) and homocysteine levels were evaluated in all cases. Defects were observed in many genetic factors and in the systems regulated by these factors. The results were compatible with those reported in the literature. In conclusion, it is possible to determine a specific family history in young adults with CVD. From this perspective, the emergence of more serious CVD may be prevented by providing disease-related information to the other family members and implementing preventive measures.     

Clinical safety and pharmacological profile of the HLA-DR antibody 1D09C3 in patients with B cell chronic lymphocytic leukemia and lymphoma: results from a phase I study

1D09C3 is a human monoclonal IgG4-type antibody against human leukocyte antigen-DR (HLA-DR) which has demonstrated pro-apoptotic activity against lymphoid tumors in vitro and in vivo. We report results from a phase I dose-escalation study which aimed to identify tolerated dosing, and the pharmacokinetic and pharmacodynamic profile of 1D09C3. Fourteen patients with relapsed/refractory B cell type leukemia/lymphoma were treated and followed after up to 4 weekly infusions of 1D09C3, administered in 6 dose levels at 0.25?C8?mg/kg/day. Treatment was tolerated well with mostly mild side effects. The most common grade III?CIV toxicities were hematological events observed in 4 patients. In one patient, treated at 8.0?mg/kg/day, a dose limiting toxicity occurred, identified as an invasive catheter-related infection. Adverse events resolved completely without long-term sequelae. 1D09C3 reduced peripheral blood B cells and monocytes by a median of 73?C81?% in all patients, with a nadir reached 30?C60?min after infusion and sustained for <96?h. Granulocytes and natural killer cells predominantly increased with variable time courses. Pharmacokinetic assessments showed detectable drug concentrations at doses 4?C8?mg/kg/day and a terminal half-life of 0.7?C7.9?h. Effective saturation of HLA-DR on peripheral blood B cells/monocytes was achieved, varying consistently with available serum concentrations and the cell-reducing activity of 1D09C3. In summary, 1D09C3 could be administered safely in patients with advanced B cell malignancies. Pharmacodynamic studies demonstrated a strong dose dependent but transient reduction of peripheral blood B cells and monocytes, consistent with a short drug serum availability.     

Alterations in promoter methylation status of tumor suppressor HIC1, SFRP2, and DAPK1 genes in prostate carcinomas

Hypermethylated genomic DNA is a common feature in tumoral tissues, although the prevalence of this modification remains poorly understood. We aimed to determine the frequency of five tumor suppressor (TS) genes in prostate cancer and the correlation between promoter hypermethylation of these genes and low and high grade of prostate carcinomas. A total of 30 prostate tumor specimens were investigated for promoter methylation status of TS hypermethylated in cancer 1 (HIC1), death-associated protein kinase 1 (DAPK1), secreted frizzled-related protein 2 (SFRP2), cyclin-dependent kinase inhibitor 2A (p16), and O-6-methylguanine-DNA methyltransferase (MGMT) genes by using bisulfite modifying method. A high frequency of promoter hypermethylation was found in HIC1 (70.9%), SFRP2 (58.3%), and DAPK1 (33.3%) genes in tumor samples that were examined. The current data show high frequency of hypermethylation changes in HIC1, SFRP2, and DAPK1 genes in prostate carcinomas of high Gleason Score (GS).