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Full-Text Articles in Medicine and Health Sciences

The Kidney-Specific Wnk1 Isoform Is Induced By Aldosterone And Stimulates Epithelial Sodium Channel-Mediated Na+ Transport, Anikó Naray-Fejes-Toth, Peter M. Snyder, Géza Fejes-Toth Dec 2004

The Kidney-Specific Wnk1 Isoform Is Induced By Aldosterone And Stimulates Epithelial Sodium Channel-Mediated Na+ Transport, Anikó Naray-Fejes-Toth, Peter M. Snyder, Géza Fejes-Toth

Dartmouth Scholarship

WNK1 belongs to a unique family of Ser/Thr kinases that have been implicated in the control of blood pressure. Intronic deletions in the WNK1 gene result in its overexpression and lead to pseudohypoaldosteronism type II, a disease with salt-sensitive hypertension and hyperkalemia. How overexpression of WNK1 leads to Na+ retention and hypertension is not entirely clear. Similarly, there is no information on the hormonal regulation of expression of WNK kinases. There are two main WNK1 transcripts expressed in the kidney: the originally described “long” WNK1 and a shorter transcript that is specifically expressed in the kidney (KS-WNK1). The goal …


Improved Quantification Of Small Objects In Near-Infrared Diffuse Optical Tomography, Subhadra Srinivasan, Brian W. Pogue, Hamid Dehghani, Shudong Jiang, Xiaomei Song, Keith D. Paulsen Nov 2004

Improved Quantification Of Small Objects In Near-Infrared Diffuse Optical Tomography, Subhadra Srinivasan, Brian W. Pogue, Hamid Dehghani, Shudong Jiang, Xiaomei Song, Keith D. Paulsen

Dartmouth Scholarship

Diffuse optical tomography allows quantification of hemoglobin, oxygen saturation, and water in tissue, and the fidelity in this quantification is dependent on the accuracy of optical properties determined during image reconstruction. In this study, a three-step algorithm is proposed and validated that uses the standard Newton minimization with Levenberg-Marquardt regularization as the first step. The second step is a modification to the existing algorithm using a two-parameter regularization to allow lower damping in a region of interest as compared to background. This second stage allows the recovery of the actual size of an inclusion. A region-based reconstruction is the final …


Update On Diabetes Mellitus, Murray Korc Oct 2004

Update On Diabetes Mellitus, Murray Korc

Dartmouth Scholarship

Diabetes mellitus is a complex multi-system disorder that may be classified as autoimmune mediated type 1 diabetes, or as insulin resistance associated type 2 diabetes. In type 1 diabetes, there is selective loss of the beta cells within the endocrine islets, as a consequence of T-cell and cytokine mediated destruction of these cells, perhaps in conjunction with destruction of the peri-islet Schwann cells. In type 2 diabetes, the etiology of the resistance ranges from post-receptor defects in the insulin signaling pathway to excessive production of adipocyte derived cytokines that antagonize insulin action to mitochondrial defects that interfere with glucose disposal. …


Differential Expression Of Toll-Like Receptors 2 And 4 In Tissues Of The Human Female Reproductive Tract, Patricia A. Pioli, Eyal Amiel, Todd M. Schaefer, John E. Connolly, Charles R. Wira, Paul M. Guyre Oct 2004

Differential Expression Of Toll-Like Receptors 2 And 4 In Tissues Of The Human Female Reproductive Tract, Patricia A. Pioli, Eyal Amiel, Todd M. Schaefer, John E. Connolly, Charles R. Wira, Paul M. Guyre

Dartmouth Scholarship

Toll-like receptor (TLR) signal transduction is a central component of the innate immune response to pathogenic challenge. Although recent studies have begun to elucidate differences in acquired immunity in tissues of the human female reproductive tract, there is a relative paucity of work regarding innate defense mechanisms. We investigated TLR mRNA and protein expression in tissues of the human female reproductive tract. Constitutive mRNA expression of TLRs 1 to 6 was observed in fallopian tubes, uterine endometrium, cervix, and ectocervix. Furthermore, transcripts of the signaling adapter MyD88 and the accessory molecule CD14 were also detected in all tissues assayed. Quantitative …


Multiple Mechanisms Regulate Numa Dynamics At Spindle Poles, Olga Kisurina-Evgenieva, Gary Mack, Quansheng Du, Ian Macara, Alexey Khodjakov, Duane A. Compton Sep 2004

Multiple Mechanisms Regulate Numa Dynamics At Spindle Poles, Olga Kisurina-Evgenieva, Gary Mack, Quansheng Du, Ian Macara, Alexey Khodjakov, Duane A. Compton

Dartmouth Scholarship

The large coiled-coil protein NuMA plays an essential role in organizing microtubule minus ends at spindle poles in vertebrate cells. Here, we use both in vivo and in vitro methods to examine NuMA dynamics at mitotic spindle poles. Using fluorescence recovery after photobleaching, we show that an exogenously expressed green-fluorescent-protein/NuMA fusion undergoes continuous exchange between soluble and spindle-associated pools in living cells. These dynamics require cellular energy and display an average half-time for fluorescence recovery of approximately 3 minutes. To explore how NuMA dynamics at spindle poles is regulated, we exploited the association of NuMA with microtubule asters formed in …


Binding Between The Niemann–Pick C1 Protein And A Photoactivatable Cholesterol Analog Requires A Functional Sterol-Sensing Domain, Nobutaka Ohgami, Dennis C. Ko, Matthew Thomas, Matthew P. Scott, Catherine C. Y. Chang, Ta-Yuan Chang Aug 2004

Binding Between The Niemann–Pick C1 Protein And A Photoactivatable Cholesterol Analog Requires A Functional Sterol-Sensing Domain, Nobutaka Ohgami, Dennis C. Ko, Matthew Thomas, Matthew P. Scott, Catherine C. Y. Chang, Ta-Yuan Chang

Dartmouth Scholarship

Niemann-Pick type C (NPC) 1 protein plays important roles in moving cholesterol and other lipids out of late endosomes by means of vesicular trafficking, but it is not known whether NPC1 directly interacts with cholesterol. We performed photoaffinity labeling of intact cells expressing fluorescent protein (FP)-tagged NPC1 by using [(3)H]7,7-azocholestanol ([(3)H]AC). After immunoprecipitation, (3)H-labeled NPC1-GFP appeared as a single band. Including excess unlabeled sterol to the labeling reaction significantly diminished the labeling. Altering the NPC1 sterol-sensing domain (SSD) with loss-of-function mutations (P692S and Y635C) severely reduced the extent of labeling. To further demonstrate the specificity of labeling, we show that …


Anemia And Blood Transfusion In The Critically Ill Patient: Role Of Erythropoietin, Howard L. Corwin Jun 2004

Anemia And Blood Transfusion In The Critically Ill Patient: Role Of Erythropoietin, Howard L. Corwin

Dartmouth Scholarship

Critically ill patients receive an extraordinarily large number of blood transfusions. Between 40% and 50% of all patients admitted to intensive care units receive at least 1 red blood cell (RBC) unit during their stay, and the average is close to 5 RBC units. RBC transfusion is not risk free. There is little evidence that 'routine' transfusion of stored allogeneic RBCs is beneficial to critically ill patients. The efficacy of perioperative recombinant human erythropoietin (rHuEPO) has been n demonstrated in a variety of elective surgical settings. Similarly, in critically ill patients with multiple organ failure, rHuEPO therapy will also stimulate …


Characterization Of Hemoglobin, Water, And Nir Scattering In Breast Tissue: Analysis Of Intersubject Variability And Menstrual Cycle Changes, Brian W. Pogue, Shudong Jiang, Hamid Dehghani, Christine Kogel, Sandra Soho, Subhadra Srinivasan, Xiaomei Song, Tor D. Tosteson, Steven P. Poplack, Keith D. Paulsen May 2004

Characterization Of Hemoglobin, Water, And Nir Scattering In Breast Tissue: Analysis Of Intersubject Variability And Menstrual Cycle Changes, Brian W. Pogue, Shudong Jiang, Hamid Dehghani, Christine Kogel, Sandra Soho, Subhadra Srinivasan, Xiaomei Song, Tor D. Tosteson, Steven P. Poplack, Keith D. Paulsen

Dartmouth Scholarship

Near-infrared imaging was used to quantify typical values of hemoglobin concentration, oxygen saturation, water fraction, scattering power, and scattering amplitude within the breast tissue of volunteer subjects. A systematic study of the menstrual variations in these parameters was carried out by measuring a group of seven premenopausal normal women (aged 41 to 47 years) in the follicular (days 7 to 14 of the cycle) and secretory phases (days 21 to 28) of the cycle, for two complete menstrual cycles. An average increase in hemoglobin concentration of 2.6 μM or 13% of the background breast values was observed in the …


The Tumor Suppressor Lkb1 Kinase Directly Activates Amp-Activated Kinase And Regulates Apoptosis In Response To Energy Stress, Reuben J. Shaw, Monica Kosmatka, Nabeel Bardeesy, Rebecca L. Hurley, Lee A. Witters, Ronald A. Depinho, Lewis C. Cantley Mar 2004

The Tumor Suppressor Lkb1 Kinase Directly Activates Amp-Activated Kinase And Regulates Apoptosis In Response To Energy Stress, Reuben J. Shaw, Monica Kosmatka, Nabeel Bardeesy, Rebecca L. Hurley, Lee A. Witters, Ronald A. Depinho, Lewis C. Cantley

Dartmouth Scholarship

AMP-activated protein kinase (AMPK) is a highly conserved sensor of cellular energy status found in all eukaryotic cells. AMPK is activated by stimuli that increase the cellular AMP/ATP ratio. Essential to activation of AMPK is its phosphorylation at Thr-172 by an upstream kinase, AMPKK, whose identity in mammalian cells has remained elusive. Here we present biochemical and genetic evidence indicating that the LKB1 serine/threonine kinase, the gene inactivated in the Peutz-Jeghers familial cancer syndrome, is the dominant regulator of AMPK activation in several mammalian cell types. We show that LKB1 directly phosphorylates Thr-172 of AMPKalpha in vitro and activates its …


Slbp Is Associated With Histone Mrna On Polyribosomes As A Component Of The Histone Mrnp, Michael L. Whitfield, Handan Kaygun, Judith A. Erkmann, W. H. Davin Townley-Tilson, Zbig Dominski, William F. Marzluff Jan 2004

Slbp Is Associated With Histone Mrna On Polyribosomes As A Component Of The Histone Mrnp, Michael L. Whitfield, Handan Kaygun, Judith A. Erkmann, W. H. Davin Townley-Tilson, Zbig Dominski, William F. Marzluff

Dartmouth Scholarship

The stem–loop binding protein (SLBP) binds the 3′ end of histone mRNA and is present both in nucleus, and in the cytoplasm on the polyribosomes. SLBP participates in the processing of the histone pre-mRNA and in translation of the mature message. Histone mRNAs are rapidly degraded when cells are treated with inhibitors of DNA replication and are stabilized by inhibitors of translation, resulting in an increase in histone mRNA levels. Here, we show that SLBP is a component of the histone messenger ribonucleoprotein particle (mRNP). Histone mRNA from polyribosomes is immunoprecipitated with anti-SLBP. Most of the SLBP in cycloheximide-treated cells …