Citations

In this article, we review how we interact with medical students in our efforts to teach blood pressure regulation and systemic cardiovascular control along with related elements of respiratory and exercise physiology. Rather than provide a detailed lecture with key facts, we attempted to outline our approach to teaching integrative cardiovascular physiology to medical students, which includes five major themes. First, focus on questions versus answers and facts. We believe that this offers both the learner and teacher a number of advantages. Second, avoid teaching dogma in the name of clarity (i.e., heavy focus on teaching “facts” that have not yet been fully investigated). This is especially important because of the way knowledge evolves over time. Third, include laboratory-based experiences in human integrative physiology. Fourth, provide students with intellectual frameworks versus a list of “facts” to serve as a platform for question generation. Finally, focus on the role of integration and regulatory redundancy in physiology and the idea that physiology is a narrative that can help. In this article, we discuss the philosophy behind the themes outlined above and argue that questions, and not answers, are where the action is for both research and education.

Abstract Background. Vitamin K1 (phylloquinone) is a fat soluble vitamin found mainly in green leafy vegetables, with smaller amounts found in other vegetables, vegetable oils, and some fruits. Vitamin K-dependent gamma-carboxylation of specific glumatic acid residues is critical to the functioning of several key proteins in the coagulation cascade. Vitamin K compounds also inhibit IL-6 and other inflammatory cytokines and serve as transcription factors that foster cell-cycle arrest and apoptosis, pathways relevant to lymphomagenesis. We tested the hypothesis that dietary and supplemental intake of Vitamin K was inversely associated with risk of NHL and the common subtypes of diffuse large B cell, follicular, and chronic lymphocytic leukemia/small lymphocytic lymphomas. Methods. We evaluated dietary and supplemental intake of vitamin K and NHL risk in a clinic-based study of 603 newly diagnosed NHL cases and 1007 frequency-matched controls enrolled at the Mayo Clinic from 2002-2008. Usual diet two years before case diagnosis or control enrollment was assessed using a self-administered, 128-item food frequency questionnaire. Dietary intake of vitamin K was estimated using the Food Processor SQL system. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CI), adjusted for age, sex, residence, and total energy. NHL subtypes were centrally reviewed, and subtype-specific risks were estimated using polychotomous logistic regression. Results. The mean age at diagnosis was 60.8 years for cases and 57% were male; for controls, the mean age at enrollment was 60.1 years and 53% were male. Median intake of vitamin K from diet among controls was 63.5 ug/day; 16% used a multivitamin supplement that included vitamin K. NHL risk was inversely associated with intake of dietary vitamin K (p-trend=0.001); compared to intake <39.3 ug/d, risk was decreased for intakes of 39.3-63.4 ug/d (OR=0.76; 95% CI 0.57-1.02), 63.5-107.7 ug/d (OR=0.74; 95% CI 0.55-1.00), and >107.7 (OR=0.56; 95% CI 0.40-0.77). There was an U-shaped association for supplemental intake of Vitamin K and NHL risk; compared to no use, supplemental intake of <5.9 ug/d (OR=0.63; 95% CI 0.37-1.08) and 5.9-17.6 ug/d (OR=0.53; 95% CI 0.30-0.93) were inversely associated with NHL risk, while intake of >17.6 ug/d (OR=1.13; 95% CI 0.73-1.74) showed no association. There was no evidence of heterogeneity by NHL subtype (p=0.4). Further adjustment for education, family history of NHL, pack-years of smoking, body mass index, and alcohol consumption did not alter these results, nor did adjustment for a food-frequency questionnaire-based estimate of total antioxidant intake. Conclusion: Higher intake of vitamin K from the diet was inversely associated with risk of NHL overall and for the major subtypes. These first results, which require replication, suggest that the coagulation pathway or other biologic effects of vitamin K may play a role in lymphomagenesis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2811.

Abstract Background. MBL is defined as a monoclonal expansion of B lymphocytes (< 5 × 109/L) in the blood without associated lymphadenopathy or organomegaly; MBLs with a chronic lymphocytic leukemia (CLL) immunophenotype have been termed as CLL-like MBL. The prevalence of CLL-like MBL in the general population is 3.5-12% but increases with age; however, the frequency is even higher (∼13-18%) among unaffected relatives from CLL families (i.e., families with two or more CLL members). We and others have found that a small proportion of individuals with CLL-like MBL individuals and lymphocytosis will progress to CLL requiring treatment (∼1.1% per year). Because CLL and NHL have been shown to aggregate together within families, suggesting a shared pathogenesis, we evaluated the frequency of MBL in NHL families. Methods. Individuals were obtained from an ongoing study of NHL families (i.e., families with 2 or more NHL members). However, we limited to NHL families with at most 1 individual with CLL due to the known increased frequency of MBL in CLL families. Multi-color flow cytometry was performed on fresh peripheral blood samples. A CBC and differential count was simultaneously obtained using an automated blood cell counter. Five possible flow diagnoses were defined as: CLL-like MBL (CD5+CD20dim), atypical MBL (CD5+CD20bright), non-CLL like MBL (CD5−), and normal immunophenotype (NIPT). Medical records of NHL cases were reviewed to confirm disease. Results. A total of 30 individuals from 16 NHL families had available flow cytometry results. The mean age at flow analysis was 56 years (range 37− 83 years). We identified 5 individuals with MBL from 4 families: 3 of the 6 had CLL-like MBL, 1 had atypical MBL, and 1 had non-CLL like MBL. The remaining 25 individuals had a NIPT. Thus, the MBL rate in NHL families is 17% (5/30). Among the CD5+ MBL (both CLL-like and atypical MBL) individuals, all were female and the mean absolute lymphocyte count was 1.4 × 109/L. Of interest, 1 of the CLL-like MBL individuals is from a family where two members had monoclonal gammopathy of uncertain significance (MGUS). Conclusion: Our data show that MBLs of various phenotypes can be found at a higher prevalence in NHL families than that of the general population. Further, the frequency of MBL in NHL families is comparable to that of CLL families. Although more work is needed, our results suggest that MBL may be clustering within NHL families, and thus support a possible common inherited predisposition of NHL and CLL, with MBL signifying a shared early pathogenetic step. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1853.

Abstract Background: Cytokine stimulated signaling pathways contribute to multiple myeloma (MM) disease progression and in acquired resistance to current treatment options making MM an incurable malignancy. The PI3K/Akt/mTOR pathway is up-regulated in MM and appears to be critical for cell proliferation and blocking this pathway might have profound impact on disease progression. In addition, this pathway also has been found to cross talk with other signal transduction pathways preventing drug-induced apoptosis. Methods: MK2206 was obtained from Merck Inc. MTT assay was performed to study drug induced cytotoxicity and thymidine uptake was used as a measure to study differences in proliferation. Flow cytometry using Annexin V-FITC and propidium iodide (PI) was used to measure drug induced apoptosis in cell lines and patient cells. In addition, apo-2.7 was also used to measure apoptosis in patient cells. Results: MK2206 treatment led to dose and time dependent decrease in cell viability as observed by MTT assay with an IC50 range of 1-5µM on most MM cell lines tested. Most of the cytotoxicity was observed by 48hours with minimal increase in cytotoxicity beyond that point. The drug was able to induce cytotoxicity in myeloma cell lines when cells were cultured with IGF, IL6, or VEGF with minimal increase in IC50 values. MK2206 also inhibited MM cell proliferation as observed by reduced thymidine uptake. This reduction in proliferation was also observed when MM cells were co-cultured with bone marrow stromal cells. When myeloma cell lines were treated with the drug for various time points, percentage of apoptotic cells increased with time of incubation with the drug as observed by flow cytometry and annexin V-FITC/PI staining. There was also a time dependent increase in caspase cleavage observed indicating that MK2206 might elicit its functions by inducing caspase dependent pathways. Further studies are being carried out to understand the importance of caspase dependent pathways for the success of anti-MM effects of MK2206. Also, MK2206 was able to induce apoptosis in patient derived primary cells, though with varying degrees of response observed between patients. Examining signaling pathways by immunoblotting demonstrated clear down regulation of pAkt and Bcl-xl levels post treatment with the drug with minimal decrease in proteins associated with other signaling pathways, like pSTAT3 and pERK. Conclusions: Taken together, our studies demonstrate significant anti-MM activity of MK2206 in-vitro. We are currently testing MK2206 in combination with known inhibitors of the other important signaling pathways implicated in MM disease biology as well as in-vivo experiments in mouse models. Performing these experiments will further validate the efficacy of MK2206 as an anti-MM agent and form the basis for it to be taken up for clinical evaluation either as a single agent or in combination with other agent(s). Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1796.

We hypothesized that individuals who have undergone gastric bypass have greater insulin sensitivity that obese subjects but less compared with lean. We measured free fatty acid (FFA) and glucose kinetics during a two-step, hyperinsulinemic euglycemic clamp in nondiabetic subjects who were 38 ± 5 mo post-gastric bypass surgery (GB; n = 15), in lean subjects (L; n = 15), and in obese subjects (O; n = 16). Fasting FFAa were not significantly different between the three study groups but during both doses of insulin were significantly higher in O than in either GB or L. The effective insulin concentration resulting in half-maximal suppression of FFA was similar in L and GB and significantly less in both groups compared with O. Glucose infusion rates during low-dose insulin were not significantly different in GB compared with either L or O. During high-dose insulin, glucose infusion rates were significantly greater in GB than in O but less than in L. Endogenous glucose production in GB was significantly lower than O only during low dose of insulin. We conclude that gastric bypass is associated with improvements in adipose tissue insulin sensitivity to levels similar to lean, healthy persons and also with improvements in the response of glucose metabolism to insulin. These changes may be due to preferential reduction in visceral fat and decreased FFA availability. However, some differences in insulin sensitivity in GB remain compared with L. Residual insulin resistance may be related to excess total body fat or abnormal lipolysis and requires further study.

Object Little information is available on follow-up MR imaging after treatment of spinal dural arteriovenous fistulas (DAVFs). The authors studied MR imaging findings in treated spinal DAVFs in relation to clinical outcomes. Methods A retrospective review of patients with spinal DAVFs who had undergone both pre- and postoperative spinal MR imaging was conducted. Postoperative MR images were obtained as routine follow-up studies or because of subjective or objective clinical deterioration. Several pre- and posttreatment MR imaging characteristics were evaluated by 2 neuroradiologists blinded to the clinical outcome. Clinical outcomes of motor, sensory, and urinary function (in relation to the patient's preoperative status) at the time of the postoperative MR imaging were obtained from the clinical record. The chi-square, Fisher exact, and rank-sum tests were performed to correlate imaging findings and changes with clinical outcomes. Results Thirty-four patients met inclusion criteria. Treatment was surgical in 33 patients and endovascular in 1 patient. Follow-up MR imaging was performed at a mean 168 ± 107 days after treatment. Twenty-seven patients (79.4%) were either clinically stable or improved, and 7 (20.6%) experienced worsening in one or more clinical outcomes. Most patients were found to have improvement of MR imaging changes. However, some degree of persistent spinal cord signal abnormality, enhancement, and swelling was observed in 31 (91.2%), 29 (85.3%), and 18 (52.3%) patients, respectively. Changes in these MR imaging characteristics compared with preoperative MR imaging did not correlate with clinical outcomes (p > 0.05), with the one exception of a significant correlation between change in urinary function and extent of spinal cord contrast enhancement (p = 0.026), a correlation of uncertain importance. Ten of the 34 patients underwent posttreatment digital subtraction angiography, and 3 of these patients had recurrent/residual DAVFs. Worsening of motor function significantly correlated with recurrent/residual DAVF (p = 0.053). Conclusions Spinal cord abnormalities persist on postoperative MR imaging studies in patients with treated spinal DAVFs, and although they tend to mildly improve with time, these changes may not correlate with clinical outcomes. However, regardless of imaging findings, worsening motor function may correlate with a recurrent or residual DAVF.