Endoscopic ultrasound-guided fine needle aspirate microsatellite loss analysis and pancreatic endocrine tumor outcome

BACKGROUND & AIMS

The clinical course of pancreatic endocrine tumor (PET) varies depending on tumor aggressiveness, disease extent, and possibly accumulated molecular alterations. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) results, although accurate in diagnosing PET, correlate poorly with PET outcome. The role of detecting key molecular abnormalities in predicting PET behavior and clinical outcome from EUS-FNA material remains unknown.

METHODS

Patients with confirmed PET who underwent EUS-FNA during a 32-month period were included. Patient demographics and clinical data were recorded and follow-up information was obtained by contacting their physician to evaluate disease progression. Representative tumor cells were microdissected from the FNA material. DNA was harvested and amplified, targeting a panel of 17 polymorphic microsatellite markers on chromosomes 1p, 3p, 5q, 9p, 10q, 11q, 17p, 17q, 21q, and 22q. The polymerase chain reaction products were subjected to fluorescent capillary gel electrophoresis to detect microsatellite loss. The fractional allelic loss (FAL) was calculated.

RESULTS

Twenty-five patients were studied. Thirteen were classified histologically as benign PET limited to the pancreas and 12 as malignant PET (invasive or metastatic). The mean FAL in the benign and malignant PET was 0.03 and 0.37 (P<.0001), respectively. In addition, the mean FAL was significantly greater in those with disease progression as compared with patients with stable disease (0.45 vs 0.09 respectively, P<.0001).

CONCLUSIONS

Microsatellite loss analysis of EUS-FNA material from PET can be performed reliably and an FAL value of more than 0.2 is associated with disease progression. This technique may have value in the preoperative assessment and risk stratification of patients with PET.

Susceptibility locus for Alzheimer's disease on chromosome 10

The apolipoprotein E (APOE) gene is the only genetic risk factor that has so far been linked to risk for late-onset Alzheimer's disease (LOAD). However, 50 percent of Alzheimer's disease cases do not carry an APOE4 allele, suggesting that other risk factors must exist. We performed a two-stage genome-wide screen in sibling pairs with LOAD to detect other susceptibility loci. Here we report evidence for an Alzheimer's disease locus on chromosome 10. Our stage one multipoint lod score (logarithm of the odds ratio for linkage/no linkage) of 2.48 (266 sibling pairs) increased to 3.83 in stage 2 (429 sibling pairs) close to D10S1225 (79 centimorgans). This locus modifies risk for Alzheimer's disease independent of APOE genotype.

Familial influence on variation in age of onset and behavioural phenotype in Alzheimer's disease

BACKGROUND

Alzheimer's disease manifests considerable heterogeneity, the cause of which is unknown.

AIMS

To determine the familial (genotypic) influence on phenomenology (phenotype) in Alzheimer's disease.

METHOD

Affected sibling pairs with Alzheimer's disease were assessed for a range of cognitive and non-cognitive symptoms. Resemblance for phenotypic characteristics was estimated using intraclass correlations for continuous traits and by pairwise concordance for dichotomous traits. The relationship between age of onset and APOE genotype was examined using linear regression analysis.

RESULTS

Significant familial effects on age of onset (intraclass correlation 0.41) and mood state (intraclass correlation 0.26), and a relatively high pairwise concordance for agitation (excess concordance 0.1) were found. The APOE locus was found to account for 4% of the variance in age of onset.

CONCLUSIONS

Substantial familial influence on age of onset, depression and agitation suggests that genotype does influence phenotype in Alzheimer's disease. Establishing the molecular basis for this phenotypic variation may prove relevant to other neuropsychiatric disorders.

No association between the alpha-2 macroglobulin I1000V polymorphism and Alzheimer's disease

Recent reports have suggested that variability in the alpha2-macroglobulin gene is a genetic risk factor for Alzheimer's disease. Here we have both tested a common polymorphism in the gene (I1000V) for association with the disease in a four-site case control study design, and tested the locus for linkage in a large series of sibpairs afflicted with late onset disease. Our results fail to show an association between this polymorphism and disease.

Educational implications of nurses' brain dominance, learning styles, and attitudes toward computerization

Nurses have been described as exhibiting computer anxiety as hospitals become automated. Suggestions have been made to provide inservice education to decrease computer anxiety before systems installation. This study examined nurses' brain dominance profiles, learning styles, and attitudes toward computers. Results indicated that 95 staff nurses had 14 different learning styles and were willing to use computers to document nursing care. As hospital inservice education programs are developed, a variety of teaching-learning methods needs to be developed to facilitate learning this new technology.

A model of biogenic amine accumulation into chromaffin granules and ghosts based on coupling to the electrochemical proton gradient

A model is presented to explain catecholamine uptake into isolated chromaffin granules and ghosts. It is based on the following observations and conclusions: 1) the chromaffin granule maintains one of the lowest permeabilities to cations of any previously isolated subcellular organelle and the lowest permeability to protons, 2) a transmembrane proton gradient delta pH exists across the chromaffin granule membrane that is not media dependent, with a measured internal pH of 5.5; 3) the addition of ATP to a suspension of chromaffin granules results in the generation of a membrane potential of 80-100 mV, positive inside; 4) an H+-translocating ATPase responsible for the generation of this electrochemical proton gradient (delta micro H+) exists within the membrane of the chromaffin granule; 5) net amine accumulation proceeds in the presence of both a delta pH alone and a transmembrane potential gradient delta psi alone, with the maximal rate and extent occurring in the presence of a delta pH and a delta psi together (delta micro H+); 6) when catecholamine uptake is in equilibrium with the delta micro H+, the equilibrium distribution of amines (delta micro A) obeys the relationship delta micro A = delta psi-2Zdelta pH. The model, in its elemental form, states that an H+-translocating ATPase for the generation of a delta pH and delta psi exists within the membrane of the chromaffin granule. This electrochemical proton gradient provides the driving force for amine influx, which proceeds via a reserpine-sensitive antiport carrier mechanism coupled to proton efflux. The model is discussed in terms of its physiological implications and significance for other amine-containing subcellular organelles, with particular respect to the species of catecholamine transported, and other unresolved issues.