The correlation between the adsorption of adhesive proteins and cell behaviour on hydroxyl-methyl mixed self-assembled monolayers

The objective of this study was to compare the biological effects of two key cell-adhesive proteins, fibronectin (FN) and vitronectin (VN), upon adsorption onto molecularly-designed model surfaces. Single-component and mixed self-assembled monolayers (SAMs) of alkanethiols on gold with OH and CH(3) terminal groups were prepared at 100%, 65%, 36% and 0% of OH at the surface, to generate a range of surfaces with a simple chemistry and a wettability gradient. FN and VN were adsorbed under non-competitive (single-protein solutions) and competitive (multi-protein solutions) conditions, and compared at different levels: adsorbed amount (radiolabelling), elution, functional presentation of cell-binding domains (ELISA), and role in mediating cell adhesion (antibody-based assay). The observed trends were related to mesenchymal stem cell response in terms of adhesion and overall cell morphology. Under non-competitive conditions, adsorption of both proteins increased with surface hydrophobicity. The presence of competitive proteins significantly decreased the adsorbed amounts, although both proteins were still detected in all SAMs. Adsorption of FN followed a trend similar to that of non-competitive conditions, while adsorption of VN was higher on 100%OH-SAMs. Concerning elution, retention of adsorbed VN was always higher than that of FN. For both proteins, functional presentation of cell-binding domains was more effective on the more hydrophilic 100%OH-SAMs. This fact, coupled to the ability of this type of SAMs to selectively recruit and retain VN in the presence of competitive serum proteins, seems to correlate with the better cell response observed on these surfaces, as compared with hydrophobic 0%OH(100%CH(3))-SAMs.     

N-acetyltransferase-2 gene polymorphisms and prostate cancer susceptibility in Latin American patients

We investigated the role of N-acetyltransferases (NAT) in prostate cancer (PCa) susceptibility. NAT are polymorphic in the population and metabolize important carcinogenic products directly involved in the tumor initiation process. This prospective case-control study utilized the polymerase chain reaction-based restriction fragment length polymorphism method and comprised a cohort of consecutive 478 individuals: 126 men with prostate cancer; 101 men with benign prostatic hyperplasia (BPH); and a control health population of 177 female and 74 male blood donors from the same region. NAT2 slow or fast acetylators genotypes were determined by the combination of four variant alleles. Lifetime occupational history, dietary patterns, cigarette smoking and other anamnestic data were obtained by interviews. We were not able to find any correlation among smoking, dietary patterns, parameters of tumor aggressiveness or patient outcome and any NAT2 genotypes or phenotypes considered in separate or in different combinations. However, there was an association between NAT2T481C (OR?=?0.47; 95% CI?=?0.26-0.84; P?=?0.01) and NAT2A803G (OR?=?0.57; 95% CI?=?0.33-0.97; P?=?0.04) polymorphisms and PCa protection. Conversely, the presence of NAT2G857A genotype increased the risk of PCa more than 3 times (OR?=?3.57; 95% CI?=?1.39-9.15; P?=?0.005). Slow acetylator NAT2*7A and NAT2*6B genotypes occurred in 10.31% of PCa but in none of BPH patients (P?=?0.0007). The control health population confirmed the results and allowed the exclusion of possible biases caused by gender influence on genotype inheritance and by the inclusion of not diagnosed prostate diseases patients among the control individuals. We suggest that the investigation of germline polymorphisms of NAT2 gene may be useful in the assessment of Latin American patients at risk of BPH and PCa.     

Proline homozygosity in codon 72 of p53 is a factor of susceptibility for thyroid cancer

A common germline polymorphism of p53 gene produces an Arginine to Proline change at aminoacid position 72. The resulting codon 72 variants have been reported associated with tumor susceptibility since they reduce p53 ability to activate apoptosis. Codon 72 polymorphism may play a role in subside vulnerability to different carcinogens and might account for ethnic variations in cancer frequency. Using an allele-specific polymerase chain reaction (PCR), we tested peripheral blood samples from 98 patients with thyroid cancer, including 21 follicular (FC) and 77 papillary carcinomas (PC), 44 patients with benign nodules, including 14 follicular adenomas and 30 goiters and 153 healthy individuals from the same geographical region. Data on lifetime occupational history, smoking history, general health conditions, previous diseases and other anamnestic data were obtained through interviews. Patients with FC (Pro/Pro=19.0%, Arg/Arg=42.9%, Arg/Pro=38%) and with PC (Pro/Pro=10.3%, Arg/Arg=36.36%, Arg/Pro=53.24%) showed a significant overrepresentation of codon 72 variants compared to the control population (Pro/Pro=1.9%, Arg/Arg=33.3%, Arg/Pro=64.7%) (P=0.0015). The Pro/Pro genotype, after adjusting for gender, age, tobacco and drugs, was associated with a markedly higher risk of FC (OR=9.714; CI: 2.334–40.436) and of PC (OR=5.299; CI: 2.334–40.436). These results provide evidence that p53 polymorphism is implicated in thyroid carcinogenesis and that individuals harboring the Pro/Pro genotype have an increased risk of developing thyroid cancer.     

Quality of life after intensive care – evaluation with EQ-5D questionnaire

OBJECTIVE: To evaluate health-related quality of life (HR-QOL) and study its determinants in adult patients discharged from an intensive care unit (ICU). DESIGN: Cohort study. SETTING: Intensive care unit (ICU), tertiary care hospital, Oporto, Portugal. PATIENTS: Of all the patients discharged over a 2 year period, 355 were considered eligible and 275 completed the study. MEASUREMENTS AND RESULTS: Patients were interviewed 6 months after ICU discharge using EuroQol 5-D (EQ-5D). At the interview only 29% reported feeling worse than 6 months before ICU admission. The proportions of those reporting moderate to extreme problems in the five dimensions studied were as follows: mobility (37%), self-care (22%), usual activities (46%), pain/discomfort (45%) and anxiety/depression (54%). Although 77% of patients reported a problem in at least one dimension, 44% referred to no problems or only moderate problems regarding pain or anxiety. EQ visual analogue scale (VAS) and EQ Index medians were 60 and 81, respectively. CONCLUSIONS: Intensive care unit variables (e.g., diagnosis, length of stay and severity of disease) and patient's background data (e.g., age, gender, education, main activity, smoking habits, experience with serious illness and previous health status) may be significant determinants of HR-QOL. However, when adjusted for background data, most ICU variables are no longer associated with EQ-5D. This should cause attention to be paid to the role of a patient's background in the evaluation of HR-QOL and to a careful interpretation of EQ-5D results when comparing ICUs.     

CD4-independent signal transduction through the T-cell receptor (TCR/CD3).

The membrane-bound CD4 glycoprotein has been proposed to act like a co-receptor along with the T-cell antigen receptor (TCR/CD3) during ligand recognition and cell activation. Due to its association with the protein tyrosine kinase (PTK) p56lck, CD4 is believed to transduce a signal and support CD3 activation of T cells. In this study we have shown that CD3 ligation on murine T-cell hybridomas induces tyrosine phosphorylation of proteins, including phospholipase C-gamma 1 (PLC gamma 1), both in the presence as well as in the absence of CD4-linked p56lck. Furthermore, using HPB clones deficient in CD3/PTK association, it has been found that the presence of CD4/p56lck does not overcome the defect in signalling. Not even co-aggregation of CD4 with CD3 triggers tyrosine phosphorylation of proteins in these cells. Together, the present results indicate that CD3-linked PTK(s) plays a primary role in the induction of signalling through TCR/CD3, and the presence of CD4/p56lck is neither necessary nor sufficient to elicit these events. In the light of these results a possible role for CD4 in antigen presentation has been proposed.