Phosphorylation of both EGFR and ErbB2 is a reliable predictor of prostate cancer cell proliferation in response to EGF

Despite multiple reports of overexpression in prostate cancer (PC), the reliance of PC cells on activated epidermal growth factor receptor (EGFR) and its downstream signaling to phosphoinositide 3'-kinase/Akt (PI3K/Akt/PTEN) and/or mitogen-activated protein kinase (MAPK/ERK) pathways has not been fully elucidated. In this study, we compared the role of EGF-mediated signaling in nonmalignant (BPH-1, PNT1A, and PNT1B) and PC cell lines (DU145, PC3, LNCaP, and CWR22Rv1). EGF-induced proliferation was observed in all EGFR-expressing PC cells except PC3, indicating that EGFR expression does not unequivocally trigger proliferation following EGF stimulation. ErbB2 recruitment potentiated EGF-induced signals and was associated with the most pronounced effects of EGF despite low EGFR expression. In this way, the sum of EGFR and ErbB2 receptor phosphorylation proved to be a more sensitive indicator of EGF-induced proliferation than quantification of the expression of either receptor alone. Both Akt and ERK were rapidly phosphorylated in response to EGF, with ERK phosphorylation being the weakest in PC3 cells. Extrapolation of these findings to clinical PC suggests that assessment of phosphorylated EGFR + ErbB2 together could serve as a marker for sensitivity to anti-EGFR-targeted therapies.     

Effect of biomaterial properties on bone healing in a rabbit tooth extraction socket model

In this work we sought to understand the effect of biomaterial properties upon healing bone tissue. We hypothesized that a hydrophilic polymer gel implanted into a bone tissue defect would impede the healing process owing to the biomaterial's prevention of protein adsorption and thus cell adhesion. To test this hypothesis, healing bone was investigated within a rabbit incisor extraction socket, a subcritical size bone defect that resists significant soft tissue invasion by virtue of its conformity. After removal of the incisor teeth, one tooth socket was left as an empty control, one was filled with crosslinked polymer networks formed from the hydrophobic polymer poly(propylene fumarate) (PPF), and one was filled with a hydrogel formed from the hydrophilic oligomer oligo(poly(ethylene glycol) fumarate) (OPF). At five different times (4 days as well as 1, 2, 4, and 8 weeks), jaw bone specimens containing the tooth sockets were removed. We analyzed bone healing by histomorphometrical analysis of hematoxylin and eosin stained sections as well as immunohistochemically stained sections. The proposed hypothesis, that a hydrophilic material would hinder bone healing, was supported by the histomorphometrical results. In addition, the immunohistochemical results reflect molecular signaling indicative of the early invasion of platelets, the vascularization of wound-healing tissue, the differentiation of migrating progenitor cells, and the formation and remodeling of bone tissue. Finally, the results emphasize the need to consider biomaterial properties and their differing effects upon endogenous growth factors, and thus bone healing, during the development of tissue engineering devices.     

Ischemic Stroke in the Setting of Tuberculous Meningitis

The clinical syndrome of tuberculous (TB) meningitis leading to ischemic strokes is rarely seen today in immunocompetent adults native to North America. This entity is also notoriously difficult to diagnose because the presenting symptoms are often nonspecific. The authors describe a case of a man with TB meningitis which progressed to recurrent ischemic cerebral infarcts.     

Establishment and characterisation of two cell lines derived from a primary adenocarcinoma of the duodenum

Aims—To establish two cell lines from a primary duodenal adenocarcinoma; to describe the morphological, growth, ploidy, and immunophenotypic characteristics of these cell lines.     

Do French medical schools provide appropriate training on gait and gait disorders?

AimEvaluate the need for integrated teaching on normal and pathological gait at medical school.MethodA questionnaire filled out by 91 French general practitioners (GPs, 130 of whom were contacted) with an average of 19 years of practice and 56 sixth-year medical students. Assessment of the students’ knowledge of normal and pathological gait.ResultsSeventy-two percent of the GPs and 82% of the students considered gait to be a frequent reason for consultation. Eighty-nine percent of the GPs and 98% of the students stated that they had difficulty analysing a gait disorder. Eighty percent of the GPs and 50% of the students considered that the teaching on gait and gait disorders at medical school was insufficient. The responses notably highlighted the poor coordination between teachers from the various disciplines involved. The students’ knowledge of gait was poor (only 20% of their answers were correct). This was especially true for semiological questions, which were correctly answered by less than one student in 10.ConclusionThe results of the present study demonstrate that French medical schools need to provide better teaching on gait. We, therefore, propose the implementation of an integrated teaching programme with a sufficient focus on functional and semiological approaches.     

Injury admissions to pediatric intensive care are predictable and preventable: a call to action

Injuries are often preventable yet remain the most common cause of death in children ages 1 to 19 years in Canada. In this retrospective case series, the authors sought to determine the proportion of injury admissions to a tertiary multidisciplinary university hospital Pediatric intensive care unit (PICU) that were preventable by known measures. Patients were a consecutive sample of 104 children, aged 99 (mean [SD] 70; range, 1-215) months, who were admitted to PICU due to injury from July 1997 to June 1998. Charts were reviewed to determine morbidity (PICU days, ventilation days, and discharge to a rehabilitation hospital), mortality, and whether the injury occurred by a preventable mechanism (as recommended by the American Academy of Pediatrics). Out of 790 admissions, 104 (13.2%) were for injury-81% unintentional and 19% intentional. Unintentional injuries occurred by diverse mechanisms, and 65/84 (77%; 95% confidence interval, 67%-86%) were potentially preventable. Unintentional injuries were especially preventable in the younger age groups (P = .009): 71% (5/7) in those<1 year; 89% (31/35) in those 1 to 4 years; 89% (16/18) in those 5 to 9 years; and 54% (13/24) in those> or =10 years. Most intentional injuries were suicide attempts in adolescents, and 88% had multiple risk factors for suicide. Patients were in PICU for 2.9 (SD 4.5) days, ventilated in 73% for 2.8 (SD 4.4) days, had a mortality of 12.5% (95% confidence interval, 6.8%- 20.4%), and demonstrated common need for rehabilitation. Thus, injuries in children resulting in admission to the PICU are common and highly preventable events with significant morbidity and mortality. Novel strategies to improve the public's perception of the cost of childhood injury are needed.     

Identification of chromosome abnormalities in subtelomeric regions by microarray analysis: a study of 5,380 cases

Subtelomeric imbalances are a significant cause of congenital disorders. Screening for these abnormalities has traditionally utilized GTG-banding analysis, fluorescence in situ hybridization (FISH) assays, and multiplex ligation-dependent probe amplification. Microarray-based comparative genomic hybridization (array-CGH) is a relatively new technology that can identify microscopic and submicroscopic chromosomal imbalances. It has been proposed that an array with extended coverage at subtelomeric regions could characterize subtelomeric aberrations more efficiently in a single experiment. The targeted arrays for chromosome microarray analysis (CMA), developed by Baylor College of Medicine, have on average 12 BAC/PAC clones covering 10 Mb of each of the 41 subtelomeric regions. We screened 5,380 consecutive clinical patients using CMA. The most common reasons for referral included developmental delay (DD), and/or mental retardation (MR), dysmorphic features (DF), multiple congenital anomalies (MCA), seizure disorders (SD), and autistic, or other behavioral abnormalities. We found pathogenic rearrangements at subtelomeric regions in 236 patients (4.4%). Among these patients, 103 had a deletion, 58 had a duplication, 44 had an unbalanced translocation, and 31 had a complex rearrangement. The detection rates varied among patients with a normal karyotype analysis (2.98%), with an abnormal karyotype analysis (43.4%), and with an unavailable or no karyotype analysis (3.16%). Six patients out of 278 with a prior normal subtelomere-FISH analysis showed an abnormality including an interstitial deletion, two terminal deletions, two interstitial duplications, and a terminal duplication. In conclusion, genomic imbalances at subtelomeric regions contribute significantly to congenital disorders. Targeted array-CGH with extended coverage (up to 10 Mb) of subtelomeric regions will enhance the detection of subtelomeric imbalances, especially for submicroscopic imbalances.     

Protein extraction and western blotting from methacarn-fixed tissue

Polyacrylamide gel electrophoresis (PAGE) of proteins with subsequent western blotting has become a routine technique for the analysis of proteins from both cultured cells and fresh whole tissue. We have developed a method to extract proteins from methacarn-fixed tissue which renders them suitable for SDS-PAGE and western blotting. With a panel of antibodies to specific intermediate filaments, transforming growth factor-α (TGF-α), and albumin, immunohistochemistry was performed in parallel with western blotting on sections cut from methacarn-fixed samples of normal rat liver and liver from rats treated under a regime which induces oval cell proliferation. Immunohistochemistry enabled the determination of changes in tissue distribution and abundance of the target proteins, which was mirrored by the corresponding western blot data. This technique can be especially effective when used in conjunction with immunohistochemistry. Tissue samples are easy to prepare, avoiding the precautions which need to be taken when handling fresh tissue (Abstract: J Pathol 1994; 173S : No. 41).     

Risk of intravascular cardiac device infections in patients with bacteraemia: impact on device removal

The risk of intravascular cardiac device infection (ICDI) has increased significantly over the last decade and is rising faster than the corresponding increase in device implantations. ICDIs may consist of pocket infections, wire infections, wire infections complicated by endocarditis, or combinations of these. In this review, we examine the microbiology of ICDIs, focusing on the risk of developing ICDI following bloodstream infections with key pathogens such as Staphylococcus aureus, coagulase-negative staphylococci, enterococci, etc., as well as the pathophysiology of these infections.