Internal Medicine Commons^™

Laser-Induced Transient Grating Analysis Of Dynamics Of Interaction Between Sensory Rhodopsin Ii D75n And The Htrii Transducer, Keiichi Inoue, Jun Sasaki, John L Spudich, Masahide Terazima

Journal Articles

The interaction between sensory rhodopsin II (SRII) and its transducer HtrII was studied by the time-resolved laser-induced transient grating method using the D75N mutant of SRII, which exhibits minimal visible light absorption changes during its photocycle, but mediates normal phototaxis responses. Flash-induced transient absorption spectra of transducer-free D75N and D75N joined to 120 amino-acid residues of the N-terminal part of the SRII transducer protein HtrII (DeltaHtrII) showed only one spectrally distinct K-like intermediate in their photocycles, but the transient grating method resolved four intermediates (K(1)-K(4)) distinct in their volumes. D75N bound to HtrII exhibited one additional slower kinetic species, which …

Expression Of The Neural Stem Cell Markers Ng2 And L1 In Human Angiomyolipoma: Are Angiomyolipomas Neoplasms Of Stem Cells?, So Dug Lim, William Stallcup, Benjamin Lefkove, Baskaran Govindarajan, Kit Sing Au, Hope Northrup, Deborah Lang, David E Fisher, Avani Patel, Mahul B Amin, Jack L Arbiser

Journal Articles

Angiomyolipomas are benign tumors of the kidney which express phenotypes of smooth muscle, fat, and melanocytes. These tumors appear with increased frequency in the autosomal dominant disorder tuberous sclerosis and are the leading cause of morbidity in adults with tuberous sclerosis. While benign, these tumors are capable of provoking life threatening hemorrhage and replacement of the kidney parenchyma, resulting in renal failure. The histogenesis of these tumors is currently unclear, although currently, we believe these tumors arise from "perivascular epithelioid cells" of which no normal counterpart has been convincingly demonstrated. Recently, stem cell precursors have been recognized that can give …

Aldosterone-Induced Sgk1 Relieves Dot1a-Af9-Mediated Transcriptional Repression Of Epithelial Na+ Channel Alpha, Wenzheng Zhang, Xuefeng Xia, Mary Rose Reisenauer, Timo Rieg, Florian Lang, Dietmar Kuhl, Volker Vallon, Bruce C Kone

Journal Articles

Aldosterone plays a major role in the regulation of salt balance and the pathophysiology of cardiovascular and renal diseases. Many aldosterone-regulated genes--including that encoding the epithelial Na+ channel (ENaC), a key arbiter of Na+ transport in the kidney and other epithelia--have been identified, but the mechanisms by which the hormone modifies chromatin structure and thus transcription remain unknown. We previously described the basal repression of ENaCalpha by a complex containing the histone H3 Lys79 methyltransferase disruptor of telomeric silencing alternative splice variant a (Dot1a) and the putative transcription factor ALL1-fused gene from chromosome 9 (Af9) as well as the release …

Severe Aortic And Arterial Aneurysms Associated With A Tgfbr2 Mutation, Scott A Lemaire, Hariyadarshi Pannu, Van Tran-Fadulu, Stacey A Carter, Joseph S Coselli, Dianna M Milewicz

Journal Articles

BACKGROUND: A 24-year-old man presented with previously diagnosed Marfan's syndrome. Since the age of 9 years, he had undergone eight cardiovascular procedures to treat rapidly progressive aneurysms, dissection and tortuous vascular disease involving the aortic root and arch, the thoracoabdominal aorta, and brachiocephalic, vertebral, internal thoracic and superior mesenteric arteries. Throughout this extensive series of cardiovascular surgical repairs, he recovered without stroke, paraplegia or renal impairment.

INVESTIGATIONS: CT scans, arteriogram, genetic mutation screening of transforming growth factor beta receptors 1 and 2.

DIAGNOSIS: Diffuse and rapidly progressing vascular disease in a patient who met the diagnostic criteria for Marfan's syndrome, …

Functional Taxonomy Of Bacterial Hyperstructures, Vic Norris, Tanneke Den Blaauwen, Armelle Cabin-Flaman, Roy H Doi, Rasika Harshey, Laurent Janniere, Alfonso Jimenez-Sanchez, Ding Jun Jin, Petra Anne Levin, Eugenia Mileykovskaya, Abraham Minsky, Milton Saier, Kirsten Skarstad

Journal Articles

The levels of organization that exist in bacteria extend from macromolecules to populations. Evidence that there is also a level of organization intermediate between the macromolecule and the bacterial cell is accumulating. This is the level of hyperstructures. Here, we review a variety of spatially extended structures, complexes, and assemblies that might be termed hyperstructures. These include ribosomal or "nucleolar" hyperstructures; transertion hyperstructures; putative phosphotransferase system and glycolytic hyperstructures; chemosignaling and flagellar hyperstructures; DNA repair hyperstructures; cytoskeletal hyperstructures based on EF-Tu, FtsZ, and MreB; and cell cycle hyperstructures responsible for DNA replication, sequestration of newly replicated origins, segregation, compaction, and …

Traumatic Brain Injury Stimulates Hippocampal Catechol-O-Methyl Transferase Expression In Microglia, John B Redell, Pramod K Dash

Journal Articles

Outcome following traumatic brain injury (TBI) is in large part determined by the combined action of multiple processes. In order to better understand the response of the central nervous system to injury, we utilized an antibody array to simultaneously screen 507 proteins for altered expression in the injured hippocampus, a structure critical for memory formation. Array analysis indicated 41 candidate proteins have altered expression levels 24h after TBI. Of particular interest was catechol-O-methyl transferase (COMT), an enzyme involved in metabolizing catecholamines released following neuronal activity. Altered catecholamine signaling has been observed after brain injury, and may contribute to the cognitive …

Phosphorylation Of The Proline-Rich Domain Of Xp95 Modulates Xp95 Interaction With Partner Proteins, Robert E Dejournett, Ryuji Kobayashi, Shujuan Pan, Chuanfen Wu, Laurence D Etkin, Richard B Clark, Oliver Bögler, Jian Kuang

Journal Articles

The mammalian adaptor protein Alix [ALG-2 (apoptosis-linked-gene-2 product)-interacting protein X] belongs to a conserved family of proteins that have in common an N-terminal Bro1 domain and a C-terminal PRD (proline-rich domain), both of which mediate partner protein interactions. Following our previous finding that Xp95, the Xenopus orthologue of Alix, undergoes a phosphorylation-dependent gel mobility shift during progesteroneinduced oocyte meiotic maturation, we explored potential regulation of Xp95/Alix by protein phosphorylation in hormone-induced cell cycle re-entry or M-phase induction. By MALDI-TOF (matrix-assisted laser-desorption ionization-time-of-flight) MS analyses and gel mobility-shift assays, Xp95 is phosphorylated at multiple sites within the N-terminal half of the …

Does Time Really Slow Down During A Frightening Event?, Chess Stetson, Matthew P Fiesta, David M Eagleman

Journal Articles

Observers commonly report that time seems to have moved in slow motion during a life-threatening event. It is unknown whether this is a function of increased time resolution during the event, or instead an illusion of remembering an emotionally salient event. Using a hand-held device to measure speed of visual perception, participants experienced free fall for 31 m before landing safely in a net. We found no evidence of increased temporal resolution, in apparent conflict with the fact that participants retrospectively estimated their own fall to last 36% longer than others' falls. The duration dilation during a frightening event, and …

A Model Of Late Long-Term Potentiation Simulates Aspects Of Memory Maintenance, Paul Smolen

Journal Articles

Late long-term potentiation (L-LTP) denotes long-lasting strengthening of synapses between neurons. L-LTP appears essential for the formation of long-term memory, with memories at least partly encoded by patterns of strengthened synapses. How memories are preserved for months or years, despite molecular turnover, is not well understood. Ongoing recurrent neuronal activity, during memory recall or during sleep, has been hypothesized to preferentially potentiate strong synapses, preserving memories. This hypothesis has not been evaluated in the context of a mathematical model representing ongoing activity and biochemical pathways important for L-LTP. In this study, ongoing activity was incorporated into two such models - …

Nuclear Localization Of Hbd-1 In Human Keratinocytes, Roger J Bick, Brian J Poindexter, L Maximilian Buja, Carl H Lawyer, Stephen M Milner, Satyanarayan Bhat

Journal Articles

OBJECTIVE: Human defensins and cathelicidins are a family of cationic antimicrobial peptides (AMPs), which play multiple roles in both innate and adaptive immune systems. They have direct antimicrobial activity against several microorganisms including burn pathogens. The majority of components of innate and adaptive immunity either express naturally occurring defensins or are otherwise chemoattracted or functionally affected by them. They also enhance adaptive immunity and wound healing and alter antibody production. All mechanisms to explain multiple functions of AMPs are not clearly understood. Prior studies to localize defensins in normal and burned skin using deconvolution fluorescence scanning microscopy indicate localization of …

Association Of Putative Enteroaggregative Escherichia Coli Virulence Genes And Biofilm Production In Isolates From Travelers To Developing Countries, Jamal A Mohamed, David B Huang, Zhi-Dong Jiang, Herbert L Dupont, James P Nataro, Jaime Belkind-Gerson, Pablo C Okhuysen

Journal Articles

Enteroaggregative Escherichia coli (EAEC) is an emerging enteric pathogen that causes acute and chronic diarrhea among children, human immunodeficiency virus-infected patients, and travelers to developing regions of the world. The pathogenesis of EAEC strains involves the production of biofilm. In this study, we determined the association between presence of putative EAEC virulence genes and biofilm formation in 57 EAEC isolates (as defined by HEp-2 adherence) from travelers with diarrhea and in 18 EAEC isolates from travelers without diarrhea. Twelve nondiarrheagenic E. coli isolates from healthy travelers were used as controls. Biofilm formation was measured by using a microtiter plate assay …

All In The Family: Atypical Hsp70 Chaperones Are Conserved Modulators Of Hsp70 Activity, Lance Shaner, Kevin A Morano

Journal Articles

Divergent relatives of the Hsp70 protein chaperone such as the Hsp110 and Grp170 families have been recognized for some time, yet their biochemical roles remained elusive. Recent work has revealed that these "atypical" Hsp70s exist in stable complexes with classic Hsp70s where they exert a powerful nucleotide-exchange activity that synergizes with Hsp40/DnaJ-type cochaperones to dramatically accelerate Hsp70 nucleotide cycling. This represents a novel evolutionary transition from an independent protein-folding chaperone to what appears to be a dedicated cochaperone. Contributions of the atypical Hsp70s to established cellular roles for Hsp70 now must be deciphered.

Infective Endocarditis In Patients With Congenitally Malformed Hearts: Characterization Of The Syndrome In A Developing Country, Bilal K. Siddiqu, M. Tariq, Atif Jadoon, Ghulam Murtaza, Asim Syed, M. Bilal Abid, Maria Qamaruddin, Mehnaz Atiq, Raymond A. Smego

Section of Internal Medicine

Cardiac surgery for correction or palliation of congenital cardiac disease in infancy and childhood remains a privilege that is rarely accessible to two-thirds of the world’s population. This imbalance has created a unique spectrum of illness in patients with underlying congenital cardiac disease and complicating infective endocarditis in developing countries, including Pakistan. In this study, we characterize endocarditis as seen in such patients presenting in Karachi.

We reviewed retrospectively patients admitted to Aga Khan University with underlying congenitally malformed hearts and endocarditis between 1991 and 2004.

We identified 48 patients with endocarditis according to the modified Duke Criterions, with just …

Poor Glycaemic Control Is The Major Factor Associated With Increased Frequency Of Gastrointestinal Symptoms In Patients With Diabetes Mellitus, Shahab Abid, Wasim Jafri, Firdous Jahan, Fauziah Rabbani, Najmul Islam, Masood H. Khan, Rana Masood

Department of Medicine

Objective:To compare the GI symptoms in diabetic patients with controls and its relationship with the complications, duration of diabetes and glycaemic control. Methods:Consecutive patients were prospectively enrolled in to two groups. Group I (diabetic patients) and Group II (non-diabetic, Controls). Patient's characteristics, demographic profiles and GI symptoms were evaluated on a questionnaire. Groups were compared for differences in various GI symptoms. Group I was further analyzed for the relationship between GI symptoms with complications, duration of diabetes andglycaemic control.
Results:Atotal of 514 patients were enrolled 250 were diabetics (group I) and 264 were non-diabetics (groupII). Mean age …

The C-Terminal Domain Of Minc Inhibits Assembly Of The Z Ring In Escherichia Coli, Daisuke Shiomi, William Margolin

Journal Articles

In Escherichia coli, the Min system, consisting of three proteins, MinC, MinD, and MinE, negatively regulates FtsZ assembly at the cell poles, helping to ensure that the Z ring will assemble only at midcell. Of the three Min proteins, MinC is sufficient to inhibit Z-ring assembly. By binding to MinD, which is mostly localized at the membrane near the cell poles, MinC is sequestered away from the cell midpoint, increasing the probability of Z-ring assembly there. Previously, it has been shown that the two halves of MinC have two distinct functions. The N-terminal half is sufficient for inhibition of FtsZ …

Genome Sequence Of Fusobacterium Nucleatum Subspecies Polymorphum - A Genetically Tractable Fusobacterium, Sandor E Karpathy, Xiang Qin, Jason Gioia, Huaiyang Jiang, Yamei Liu, Joseph F Petrosino, Shailaja Yerrapragada, George E Fox, Susan Kinder Haake, George M Weinstock, Sarah K Highlander

Journal Articles

Fusobacterium nucleatum is a prominent member of the oral microbiota and is a common cause of human infection. F. nucleatum includes five subspecies: polymorphum, nucleatum, vincentii, fusiforme, and animalis. F. nucleatum subsp. polymorphum ATCC 10953 has been well characterized phenotypically and, in contrast to previously sequenced strains, is amenable to gene transfer. We sequenced and annotated the 2,429,698 bp genome of F. nucleatum subsp. polymorphum ATCC 10953. Plasmid pFN3 from the strain was also sequenced and analyzed. When compared to the other two available fusobacterial genomes (F. nucleatum subsp. nucleatum, and F. nucleatum subsp. vincentii) 627 open reading frames unique …