Citations

Suprastimulation of pancreatic acini is a well-known model for pancreatitis, and it is characterized by actin reorganization and cell blebbing. Currently, however, the mechanisms underlying regulation of these aberrant cytoskeletal and membrane dynamics and how they contribute to cell injury are unclear. We observed that suprastimulation results in a rapid activation of Src and relocalization of the actin-binding protein cortactin from the apical to the basolateral domain at the necks of membrane blebs. Furthermore, Src-mediated cortactin tyrosine phosphorylation was markedly increased after suprastimulation. Pretreatment of acini with Src inhibitors or expression of a cortactin tyrosine phospho-inhibitory mutant reduced actin redistribution and bleb formation induced by suprastimulation in vitro. Importantly, inhibition of Src activity in rat models of suprastimulation-induced pancreatitis substantially reduced disease severity, as indicated by a reduction in serum amylase and pancreatic edema and a striking improvement in tissue histology. These findings indicate a novel, disease-relevant role for Src-mediated cortactin phosphorylation in aberrant reorganization of the actin cytoskeleton, a mechanism that is likely to have implications in other types of cell injury. In addition, they suggest a potential use for Src inhibitors as an approach to reduce cell injury.

Phenylethanolamine N-methyltransferase (PNMT) catalyzes the synthesis of epinephrine from norepinephrine. We previously identified and functionally characterized common sequence variation in the PNMT gene. In the present study, we set out to determine whether common PNMT genetic polymorphisms might be associated with individual variation in circulating epinephrine levels during exercise in 74 Caucasian American subjects. Circulating epinephrine levels were measured in each subject at baseline and during two different levels of exercise, ∼40% and ∼75% of peak workload. The PNMT gene was resequenced with DNA from each study subject. Eight novel PNMT polymorphisms were identified, including a C319T (Arg107Cys) nonsynonymous single nucleotide polymorphism (SNP) and I1G(280)A, a SNP located in the first intron of the gene. The I1G(280)A SNP was significantly associated with decreased exercise-induced circulating epinephrine levels and with a decreased epinephrine-to-norepinephrine ratio. The Cys107 recombinant allozyme displayed significantly lower levels of both PNMT activity and immunoreactive protein than the wild-type allozyme after transfection into COS-1 cells, but it did not appear to be associated with level of epinephrine in these subjects. Electrophoretic mobility shift and reporter gene assays performed with the I1G(280)A SNP indicated that this polymorphism could bind nuclear proteins and might modulate gene transcription. Our studies suggest that functionally significant variant sequence in the human PNMT gene might contribute to individual variation in levels of circulating epinephrine during exercise.

Initial studies indicate an increased prevalence of patent foramen ovale (PFO) in migraineurs with aura, and an increased prevalence of migraine and migraine with aura in persons with PFO. Retrospective analyses of PFO closure suggest clinically significant improvements in migraine patterns. The aim of this study was to examine the prevalence of migraine in patients with PFO, the prevalence of PFO in migraineurs, and the effect of PFO closure on migraine. We conducted a quantitative systematic review of articles on migraine and PFO that met inclusion criteria, then reviewed, appraised, and subjected them to data extraction. Of 134 articles identified, 18 met a priori selection criteria. The estimated strength of association between PFO and migraine, reflected by summary odds ratios (ORs), was 5.13 [95% confidence interval (CI) 4.67, 5.59], and between PFO and migraine with aura the OR was 3.21 (95% CI 2.38, 4.17). The grade of evidence was low. The association between migraine and PFO was OR 2.54 (95% CI 2.01, 3.08). The grade of evidence was low to moderate. Six studies of PFO closure suggested improvement in migraine, but had a very low grade of evidence. The low-to-moderate grade of evidence from observational studies supports an apparent association between PFO and migraine. Although PFO closure seemed to affect migraine patterns favourably, the very low grade of available evidence to support this association precludes definitive conclusions.

Abstract The Multiple Myeloma Research Consortium has established a tissue bank for the deposition of bone marrow samples from patients with multiple myeloma to be mailed and processed under good laboratory practices. To date, over 1,000 samples have been collected. At this time, limited information is available on shipped bone marrow aspirates in regards to cell viability, yield, purity, and subsequent RNA yield and quality. To test these determinants, we did a pilot study on behalf of the Multiple Myeloma Research Consortium where samples were drawn at Mayo Clinic Rochester (MCR) pooled and split into two equal aliquots. One-half of each sample was processed following good laboratory practices compliant standard operating procedures, immediately after sample procurement, at MCR. The CD138+ cells were stored at -80°C as a Trizol lysate. The other half of the aspirate was sent overnight to Mayo Clinic Scottsdale where they were processed using identical standard operating procedures. The RNA was extracted and analyzed in a single batch at MCR. At both locations, samples were assayed for the following quality determinants: Viability was assessed using a three-color flow cytometric method (CD45, CD38, and 7-AAD). Cell counts were done to determine plasma cell recovery and post-sort purity determined by means of a slide-based immunofluorescent assay. RNA recovery and integrity was assessed using the Agilent Bioanalyzer. Lastly, gene expression profiles were compared to determine the signature emanating from the shipment of samples. Despite minor differences, our results suggest that shipment of samples did not significantly affect these quality determinants in aggregate. (Cancer Epidemiol Biomarkers Prev 2008;17(3):666–73)

Abstract The cyclooxygenase (COX)-2 enzyme appears to be an important target for cancer chemoprevention. Given the recent emergence of potentially serious cardiovascular toxicity associated with selective COX-2 inhibitors, nonsteroidal antiinflammatory drugs (NSAIDs), which inhibit both COX-1 and COX-2, have received renewed attention as candidate chemoprevention agents. Sulindac has shown consistent chemopreventive potential in preclinical studies as well as in a limited number of clinical trials reported to date. For the current pharmacokinetic study, sulindac capsules were prepared to facilitate ample agent supplies for future intervention studies. Encapsulation of the parent compound (sulindac sulfoxide) can be readily accomplished, but the effects of alternate formulations on bioavailability have not been rigorously examined. In the present single-dose, two-period crossover trial, we conducted pharmacokinetic analyses of sulindac in capsule (test) versus tablet (reference) formulations. Overall, bioavailability appeared to be higher for the capsule compared with the tablet formulation based on test-to-reference pharmacokinetic variable ratios for the parent compound alone. However, additional analyses based on the sulfide and sulfone metabolites of sulindac with the same pharmacokinetic variables indicated similar chemopreventive exposures between the capsule and tablet formulations. These data support the use of sulindac capsules, which can be readily prepared with matching placebos, in future blinded chemoprevention trials. (Cancer Epidemiol Biomarkers Prev 2008;17(3):674–9)

Abstract We found no significant excess of fractures among Rochester, MN, residents with diabetes mellitus initially recognized in 1950–1969, but more recent studies elsewhere have documented an apparent increase in hip fracture risk. To explore potential explanations for any increase in fractures, we performed an historical cohort study among 1964 Rochester residents who first met glycemic criteria for diabetes in 1970–1994 (mean age, 61.7 ± 14.0 yr; 51% men). Fracture risk was estimated by standardized incidence ratios (SIRs), and risk factors were evaluated in Andersen-Gill time-to-fracture regression models. In 23,236 person-years of follow-up, 700 diabetic residents experienced 1369 fractures documented by medical record review. Overall fracture risk was elevated (SIR, 1.3; 95% CI, 1.2–1.4), but hip fractures were increased only in follow-up beyond 10 yr (SIR, 1.5; 95% CI, 1.1–1.9). As expected, fracture risk factors included age, prior fracture, secondary osteoporosis, and corticosteroid use, whereas higher physical activity and body mass index were protective. Additionally, fractures were increased among patients with neuropathy (hazard ratio [HR], 1.3; 95% CI, 1.1–1.6) and those on insulin (HR, 1.3; 95% CI, 1.1–1.5); risk was reduced among users of biquanides (HR, 0.7; 95% CI, 0.6–0.96), and no significant influence on fracture risk was seen with sulfonylurea or thiazolidinedione use. Thus, contrary to our earlier study, the risk of fractures overall (and hip fractures specifically) was increased among Rochester residents with diabetes, but there was no evidence that the rise was caused by greater levels of obesity or newer treatments for diabetes.