Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 27
Filter
1.
J Contin Educ Nurs ; 54(12): 574-580, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37855823

ABSTRACT

BACKGROUND: Caring for pediatric patients at the end of life (EOL) can lead to anxiety and burnout for critical care nurses. New graduate nurses (NGNs) often report receiving inadequate education related to EOL care and then enter the workforce with limited clinical experience in caring for patients at EOL. A quality improvement project at a pediatric academic hospital sought to determine whether a simulation-based educational program for NGNs working in critical care could reduce anxiety about EOL care. METHOD: Eight NGNs participated in a case study and simulation-based educational program that encompassed topics such as communication, symptom management, postmortem care, and support for the family at EOL. Anxiety was measured pre- and postprogram with the Spielberger State-Trait Anxiety Inventory (STAI©). RESULTS: Anxiety levels after participation in the EOL educational program decreased by 24.1% from preprogram levels. CONCLUSION: Providing NGNs in critical care with a case- and simulation-based EOL educational program can reduce anxiety levels and potentially decrease caregiver burnout. [J Contin Educ Nurs. 2023;54(12):574-580.].


Subject(s)
Nurses , Terminal Care , Humans , Child , Palliative Care , Communication , Anxiety/prevention & control
2.
Ther Innov Regul Sci ; 54(6): 1404-1415, 2020 11.
Article in English | MEDLINE | ID: mdl-32472442

ABSTRACT

BACKGROUND: Pharmaceutical companies and regulatory agencies endeavor to relate their decision making with outcomes to improve future decision making and to ensure that gained knowledge is fed back into a learning system. Nevertheless, such a correlation can only be achieved by documenting the expected outcome of a decision at the time it is made, enabling comparison of the expected outcome with the actual result. METHODS: Participants at an international workshop discussed how the documentation of decisions could be evolved as companies and agencies look to improve their knowledge base. Discussions were informed by a pre-workshop survey of pharmaceutical companies and regulatory agencies. RESULTS: Most survey participants from 12 companies (55% response rate) and 11 agencies (73% response) have a system in place to enable documentation of major decisions, however, systems are used primarily to document outcomes rather than the process, while information from documentation is not always used, and feedback loops are not in place. The majority of participants indicated that their organization currently documents most decision-making practices included in the proposed template. Workshop participants agreed that all major past decisions should be referenceable and suggested incentives to enable decisions to be referenced, and confirmed elements and characteristics of a decision-documentation template. CONCLUSIONS: This survey and workshop identified the current landscape and gaps in the documentation of decision making and suggested revisions for a proposed documentation template. The use of technology to enable information extraction with support from artificial intelligence and future decision making was a recommendation highlighted by participants.


Subject(s)
Pharmaceutical Preparations , Artificial Intelligence , Documentation , Government Agencies , Humans , Surveys and Questionnaires
3.
Clin Pharmacol Ther ; 105(4): 935-942, 2019 04.
Article in English | MEDLINE | ID: mdl-30472729

ABSTRACT

There is a growing interest in aligning accelerated regulatory pathways with flexible access and reimbursement pathways to expedite the equitable availability of high-quality, safe, and effective medicines that provide a value-based approach to meeting society's most important healthcare needs. The Centre for Innovation in Regulatory Science (CIRS) identified key issues regarding the confluence of regulatory and health technology assessment processes from discussions and presentations given by international regulators, health technology assessment bodies, payers, patient representatives, and multinational pharmaceutical company representatives on this topic at CIRS workshops held in 2014 and 2017 that focused on the commonalties and differences across these pathways. Recent publications have also been highlighted. The barriers to and opportunities for aligning stakeholder expectations and needs were investigated and recommendations provided. Early dialogue among the stakeholders is the process that will likely provide the greatest return on investment of time and effort to identify, develop, review, and recommend important new medicines, especially those that address an unmet medical need.


Subject(s)
Drug Industry/legislation & jurisprudence , Technology Assessment, Biomedical/legislation & jurisprudence , Delivery of Health Care/legislation & jurisprudence , Government Regulation , Humans
4.
Nature ; 523(7562): 617-20, 2015 Jul 30.
Article in English | MEDLINE | ID: mdl-26223627

ABSTRACT

Intracellular energy distribution has attracted much interest and has been proposed to occur in skeletal muscle via metabolite-facilitated diffusion; however, genetic evidence suggests that facilitated diffusion is not critical for normal function. We hypothesized that mitochondrial structure minimizes metabolite diffusion distances in skeletal muscle. Here we demonstrate a mitochondrial reticulum providing a conductive pathway for energy distribution, in the form of the proton-motive force, throughout the mouse skeletal muscle cell. Within this reticulum, we find proteins associated with mitochondrial proton-motive force production preferentially in the cell periphery and proteins that use the proton-motive force for ATP production in the cell interior near contractile and transport ATPases. Furthermore, we show a rapid, coordinated depolarization of the membrane potential component of the proton-motive force throughout the cell in response to spatially controlled uncoupling of the cell interior. We propose that membrane potential conduction via the mitochondrial reticulum is the dominant pathway for skeletal muscle energy distribution.


Subject(s)
Energy Metabolism , Mitochondria, Muscle/metabolism , Muscle, Skeletal/cytology , Muscle, Skeletal/metabolism , Adenosine Triphosphatases/metabolism , Adenosine Triphosphate/biosynthesis , Adenosine Triphosphate/metabolism , Animals , Diffusion , Male , Membrane Potential, Mitochondrial , Mice , Mice, Inbred C57BL , Mitochondrial Proteins/metabolism , Proton-Motive Force
5.
Cell ; 160(4): 619-630, 2015 Feb 12.
Article in English | MEDLINE | ID: mdl-25679758

ABSTRACT

A central paradigm within virology is that each viral particle largely behaves as an independent infectious unit. Here, we demonstrate that clusters of enteroviral particles are packaged within phosphatidylserine (PS) lipid-enriched vesicles that are non-lytically released from cells and provide greater infection efficiency than free single viral particles. We show that vesicular PS lipids are co-factors to the relevant enterovirus receptors in mediating subsequent infectivity and transmission, in particular to primary human macrophages. We demonstrate that clustered packaging of viral particles within vesicles enables multiple viral RNA genomes to be collectively transferred into single cells. This study reveals a novel mode of viral transmission, where enteroviral genomes are transmitted from cell-to-cell en bloc in membrane-bound PS vesicles instead of as single independent genomes. This has implications for facilitating genetic cooperativity among viral quasispecies as well as enhancing viral replication.


Subject(s)
Cytoplasmic Vesicles/virology , Enterovirus Infections/transmission , Enterovirus/physiology , Macrophages/virology , Cytoplasmic Vesicles/chemistry , Humans , Macrophages/cytology , Phosphatidylserines , Poliovirus/physiology , RNA, Viral/metabolism , Rhinovirus/physiology , Virus Replication
6.
J Histochem Cytochem ; 63(1): 8-21, 2015 01.
Article in English | MEDLINE | ID: mdl-25362141

ABSTRACT

Using the intrinsic optical properties of collagen and elastin, two-photon microscopy was applied to evaluate the three-dimensional (3D) macromolecular structural development of the mouse thoracic aorta from birth to 60 days old. Baseline development was established in the Scavenger Receptor Class B Type I-Deficient, Hypomorphic Apolipoprotein ER61 (SR-BI KO/ApoeR61(h/h)) mouse in preparation for modeling atherosclerosis. Precise dissection enabled direct observation of the artery wall in situ. En-face, optical sectioning of the aorta provided a novel assessment of the macromolecular structural development. During aortic development, the undulating lamellar elastin layers compressed consistent with the increases in mean aortic pressure with age. In parallel, a net increase in overall wall thickness (p<0.05, in day 60 compared with day 1 mice) occurred with age whereas the ratio of the tunicas adventitia and media to full aortic thickness remained nearly constant across age groups (~1:2.6, respectively). Histochemical analyses by brightfield microscopy and ultrastructure validated structural proteins and lipid deposition findings derived from two-photon microscopy. Development was associated with decreased decorin but not biglycan proteoglycan expression. This non-destructive 3D in situ approach revealed the aortic wall microstructure development. Coupling this approach with the intrinsic optical properties of the macromolecules may provide unique vascular wall 3D structure in many pathological conditions, including aortic atherosclerosis, dissections and aneurysms.


Subject(s)
Aorta, Thoracic/growth & development , Microscopy, Fluorescence, Multiphoton , Animals , Aorta, Thoracic/cytology , Aorta, Thoracic/metabolism , Apolipoproteins E/deficiency , Apolipoproteins E/genetics , CD36 Antigens/deficiency , CD36 Antigens/genetics , Gene Knockout Techniques , Imaging, Three-Dimensional , Mice
7.
J Cell Sci ; 126(Pt 21): 4843-9, 2013 Nov 01.
Article in English | MEDLINE | ID: mdl-24006259

ABSTRACT

Because nutrient-sensing nuclear and cytosolic acetylation mediates cellular autophagy, we investigated whether mitochondrial acetylation modulates mitochondrial autophagy (mitophagy). Knockdown of GCN5L1, a component of the mitochondrial acetyltransferase machinery, diminished mitochondrial protein acetylation and augmented mitochondrial enrichment of autophagy mediators. This program was disrupted by SIRT3 knockdown. Chronic GCN5L1 depletion increased mitochondrial turnover and reduced mitochondrial protein content and/or mass. In parallel, mitochondria showed blunted respiration and enhanced 'stress-resilience'. Genetic disruption of autophagy mediators Atg5 and p62 (also known as SQSTM1), as well as GCN5L1 reconstitution, abolished deacetylation-induced mitochondrial autophagy. Interestingly, this program is independent of the mitophagy E3-ligase Parkin (also known as PARK2). Taken together, these data suggest that deacetylation of mitochondrial proteins initiates mitochondrial autophagy in a canonical autophagy-mediator-dependent program and shows that modulation of this regulatory program has ameliorative mitochondrial homeostatic effects.


Subject(s)
Autophagy , Mitochondria/metabolism , Mitochondrial Proteins/metabolism , Acetylation , Animals , HEK293 Cells , HeLa Cells , Humans , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Mitochondria/enzymology , Mitochondria/genetics , Mitochondrial Proteins/genetics , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/metabolism , Ubiquitin-Protein Ligases/genetics , Ubiquitin-Protein Ligases/metabolism
8.
Nat Med ; 19(10): 1281-7, 2013 Oct.
Article in English | MEDLINE | ID: mdl-24056772

ABSTRACT

Endothelial secretion of von Willebrand factor (VWF) from intracellular organelles known as Weibel-Palade bodies (WPBs) is required for platelet adhesion to the injured vessel wall. Here we demonstrate that WPBs are often found near or within autophagosomes and that endothelial autophagosomes contain abundant VWF protein. Pharmacological inhibitors of autophagy or knockdown of the essential autophagy genes Atg5 or Atg7 inhibits the in vitro secretion of VWF. Furthermore, although mice with endothelial-specific deletion of Atg7 have normal vessel architecture and capillary density, they exhibit impaired epinephrine-stimulated VWF release, reduced levels of high-molecular weight VWF multimers and a corresponding prolongation of bleeding times. Endothelial-specific deletion of Atg5 or pharmacological inhibition of autophagic flux results in a similar in vivo alteration of hemostasis. Thus, autophagy regulates endothelial VWF secretion, and transient pharmacological inhibition of autophagic flux may be a useful strategy to prevent thrombotic events.


Subject(s)
Autophagy , Endothelial Cells/metabolism , von Willebrand Factor/metabolism , Autophagy-Related Protein 5 , Autophagy-Related Protein 7 , Exocytosis , Hemostasis , Humans , Microtubule-Associated Proteins/genetics , Ubiquitin-Activating Enzymes/genetics , Weibel-Palade Bodies/metabolism
9.
Mol Microbiol ; 86(1): 187-98, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22897198

ABSTRACT

Recently, we described the existence of the ubiquitin fold modifier 1 (Ufm1) and its conjugation pathway in Leishmania donovani. We demonstrated the conjugation of Ufm1 to proteins such as mitochondrial trifunctional protein (MTP) that catalyses ß-oxidation of fatty acids in L. donovani. To elucidate the biological roles of the Ufm1-mediated modifications, we made an L. donovani Ufm1 null mutant (Ufm1(-/-)). Loss of Ufm1 and consequently absence of Ufm1 conjugation with MTP resulted in diminished acetyl-CoA, the end-product of the ß-oxidation in the Ufm1(-/-) amastigote stage. The Ufm1(-/-) mutants showed reduced survival in the amastigote stage in vitro and ex vivo in human macrophages. This survival was restored by re-expression of wild-type Ufm1 with concomitant induction of acetyl-CoA but not by re-expressing the non-conjugatable Ufm1, indicating the essential nature of Ufm1 conjugation and ß-oxidation. Both cell cycle analysis and ultrastructural studies of Ufm1(-/-) parasites confirmed the role of Ufm1 in amastigote growth. The defect in vitro growth of amastigotes in human macrophages was further substantiated by reduced survival. Therefore, these studies suggest the importance of Ufm1 in Leishmania pathogenesis with larger impact on other organisms and further provide an opportunity to test Ufm1(-/-) parasites as drug and vaccine targets.


Subject(s)
Cell Division , Fatty Acids/metabolism , Gene Deletion , Leishmania donovani/enzymology , Leishmania donovani/physiology , Protozoan Proteins/metabolism , Ubiquitin/metabolism , Cell Survival , Genetic Complementation Test , Humans , Leishmania donovani/genetics , Macrophages/immunology , Macrophages/parasitology , Oxidation-Reduction , Protozoan Proteins/genetics
10.
Circulation ; 125(18): 2232-42, 2012 May 08.
Article in English | MEDLINE | ID: mdl-22499950

ABSTRACT

BACKGROUND: Patients with congenital heart disease (CHD) and heterotaxy show high postsurgical morbidity/mortality, with some developing respiratory complications. Although this finding is often attributed to the CHD, airway clearance and left-right patterning both require motile cilia function. Thus, airway ciliary dysfunction (CD) similar to that of primary ciliary dyskinesia (PCD) may contribute to increased respiratory complications in heterotaxy patients. METHODS AND RESULTS: We assessed 43 CHD patients with heterotaxy for airway CD. Videomicrocopy was used to examine ciliary motion in nasal tissue, and nasal nitric oxide (nNO) was measured; nNO level is typically low with PCD. Eighteen patients exhibited CD characterized by abnormal ciliary motion and nNO levels below or near the PCD cutoff values. Patients with CD aged >6 years show increased respiratory symptoms similar to those seen in PCD. Sequencing of all 14 known PCD genes in 13 heterotaxy patients with CD, 12 without CD, 10 PCD disease controls, and 13 healthy controls yielded 0.769, 0.417, 1.0, and 0.077 novel variants per patient, respectively. One heterotaxy patient with CD had the PCD causing DNAI1 founder mutation. Another with hyperkinetic ciliary beat had 2 mutations in DNAH11, the only PCD gene known to cause hyperkinetic beat. Among PCD patients, 2 had known PCD causing CCDC39 and CCDC40 mutations. CONCLUSIONS: Our studies show that CHD patients with heterotaxy have substantial risk for CD and increased respiratory disease. Heterotaxy patients with CD were enriched for mutations in PCD genes. Future studies are needed to assess the potential benefit of prescreening and prophylactically treating heterotaxy patients for CD.


Subject(s)
Ciliary Motility Disorders/epidemiology , Heart Defects, Congenital/epidemiology , Heterotaxy Syndrome/epidemiology , Respiratory System Abnormalities/epidemiology , Adolescent , Adult , Axonemal Dyneins/genetics , Breath Tests , Child , Child, Preschool , Ciliary Motility Disorders/genetics , Cytoskeletal Proteins , Female , Heart Defects, Congenital/genetics , Heterotaxy Syndrome/genetics , Humans , Infant , Male , Microscopy, Video , Middle Aged , Mutation , Nitric Oxide/analysis , Prevalence , Proteins/genetics , Respiratory System Abnormalities/genetics , Young Adult
11.
J Anat ; 220(5): 514-24, 2012 May.
Article in English | MEDLINE | ID: mdl-22360411

ABSTRACT

The high spatial resolution of micro-computed tomography (micro-CT) is ideal for 3D imaging of coronary arteries in intact mouse heart specimens. Previously, micro-CT of mouse heart specimens utilized intravascular contrast agents that hardened within the vessel lumen and allowed a vascular cast to be made. However, for mouse coronary artery disease models, it is highly desirable to image coronary artery walls and highlight plaques. For this purpose, we describe an ex vivo contrast-enhanced micro-CT imaging technique based on tissue staining with osmium tetroxide (OsO(4) ) solution. As a tissue-staining contrast agent, OsO(4) is retained in the vessel wall and surrounding tissue during the fixation process and cleared from the vessel lumens. Its high X-ray attenuation makes the artery wall visible in CT. Additionally, since OsO(4) preferentially binds to lipids, it highlights lipid deposition in the artery wall. We performed micro-CT of heart specimens of 5- to 25-week-old C57BL/6 wild-type mice and 5- to 13-week-old apolipoprotein E knockout (apoE(-/-) ) mice at 10 µm resolution. The results show that walls of coronary arteries as small as 45 µm in diameter are visible using a table-top micro-CT scanner. Similar image clarity was achieved with 1/2000th the scan time using a synchrotron CT scanner. In 13-week-old apoE mice, lipid-rich plaques are visible in the aorta. Our study shows that the combination of OsO(4) and micro-CT permits the visualization of the coronary artery wall in intact mouse hearts.


Subject(s)
Coronary Vessels/anatomy & histology , Osmium Tetroxide , X-Ray Microtomography/methods , Animals , Female , Male , Mice , Mice, Inbred C57BL
12.
Antioxid Redox Signal ; 16(1): 45-56, 2012 Jan 01.
Article in English | MEDLINE | ID: mdl-21834687

ABSTRACT

AIMS: Nitric oxide (NO) and protein S-nitrosylation (SNO) play important roles in ischemic preconditioning (IPC)-induced cardioprotection. Mitochondria are key regulators of preconditioning, and most proteins showing an increase in SNO with IPC are mitochondrial. The aim of this study was to address how IPC transduces NO/SNO signaling to mitochondria in the heart. RESULTS: In this study using Langendorff perfused mouse hearts, we found that IPC-induced cardioprotection was blocked by treatment with either N-nitro-L-arginine methyl ester (L-NAME, a constitutive NO synthase inhibitor), ascorbic acid (a reducing agent to decompose SNO), or methyl-?-cyclodextrin (M?CD, a cholesterol sequestering agent to disrupt caveolae). IPC not only activated AKT/eNOS signaling but also led to translocation of eNOS to mitochondria. M?CD treatment disrupted caveolar structure, leading to dissociation of eNOS from caveolin-3 and blockade of IPC-induced activation of the AKT/eNOS signaling pathway. A significant increase in mitochondrial SNO was found in IPC hearts compared to perfusion control, and the disruption of caveolae by M?CD treatment not only abolished IPC-induced cardioprotection, but also blocked the IPC-induced increase in SNO. INNOVATION: These results provide mechanistic insight into how caveolae/eNOS/NO/SNO signaling mediates cardioprotection induced by IPC. CONCLUSION: Altogether these results suggest that caveolae transduce eNOS/NO/SNO cardioprotective signaling in the heart.


Subject(s)
Caveolae/metabolism , Ischemic Preconditioning, Myocardial , Mitochondrial Proteins/metabolism , Nitric Oxide/metabolism , Animals , Caveolin 3/metabolism , Enzyme Activation/drug effects , Heart/drug effects , Male , Mice , Mice, Inbred C57BL , Mitochondria/metabolism , Myocardium/metabolism , Nitric Oxide Synthase Type III/metabolism , Oxidation-Reduction , Phosphorylation/drug effects , Protein Binding/drug effects , Proto-Oncogene Proteins c-akt/metabolism , Sarcolemma/drug effects , Sarcolemma/metabolism , Signal Transduction/drug effects , beta-Cyclodextrins/pharmacology
13.
Nurs Adm Q ; 35(2): 164-73, 2011.
Article in English | MEDLINE | ID: mdl-21403490

ABSTRACT

PURPOSE: Health care organizations that employ advanced practice nurses are challenged to evaluate practice at this advanced level. Current evaluation methods tend to inter-mingle basic nursing competencies with competencies found in medical practice and organizational objectives that are typically derived from human resources departments. This article describes the development of a criterion-based job performance assessment for advanced nursing practice using a framework rooted in a nursing theory. METHOD: A needs analysis; review of the literature, adaptation of nursing's Synergy Model, and input from various stakeholders guided the development of a generic job description. This job description progressed into a criterion-based performance assessment. Construct validity was tested using a questionnaire administered to a convenience sample of 9 practicing advanced practice nurses, 2 nurse executives, 1 PhD nurse educator, and 1 physician. CONCLUSION: Autonomy, job satisfaction, and quality improvement for advanced practice nurses are fostered by a review process that defines roles and competencies specific to advanced nursing practice. Peer review, a concept contributing to this process is explored as a means to monitor and improve practice.


Subject(s)
Advanced Practice Nursing/standards , Clinical Competence/standards , Diffusion of Innovation , Employee Performance Appraisal/methods , Job Satisfaction , Professional Autonomy , Employee Performance Appraisal/standards , Humans , Models, Nursing , Needs Assessment , New Jersey , Nursing Evaluation Research , Peer Review, Health Care/methods , Program Development , Quality Improvement , Task Performance and Analysis
14.
Laryngoscope ; 120 Suppl 4: S221, 2010.
Article in English | MEDLINE | ID: mdl-21225819

ABSTRACT

OBJECTIVE: To investigate the impact of adenotonsillectomy on asthma in the pediatric population. STUDY DESIGN: Retrospective chart review. METHODS: All children who underwent adenotonsillectomy at our institution from 2002-2007 were identified from a medical records database. Of the 560 charts reviewed, 93 of the patients had the diagnosis of asthma from a pediatric pulmonologist. Outcome measures of asthma control were analyzed one year preoperatively and one year postoperatively and included: hospital visits, systemic steroid use, asthma medication use, and asthma control test scores. RESULTS: There was a statistically significant improvement in postoperative asthma severity in all measures including mean hospital visits, systemic steroid administration, asthma medication use, and childhood asthma control test scores (p<0.01). CONCLUSION: This study suggests that adenotonsillectomy, which provides improvement in the upper airway of children, may in turn lead to improvement of the lower airways of children, especially those with bronchial asthma.


Subject(s)
Adenoidectomy , Asthma/surgery , Tonsillectomy , Analysis of Variance , Child , Child, Preschool , Female , Humans , Length of Stay/statistics & numerical data , Male , Retrospective Studies , Sleep Apnea, Obstructive/surgery , Treatment Outcome
15.
Laryngoscope ; 119(10): 1927-31, 2009 Oct.
Article in English | MEDLINE | ID: mdl-19655337

ABSTRACT

OBJECTIVES/HYPOTHESIS: To develop a program for teaching robotic skills to residents. To assess the development of proficiency in basic robotic surgical skills in a resident cohort. STUDY DESIGN: Prospective educational project using a commercially available surgical robot. Residents use a surgical robot to complete a designated set of tasks intended to simulate surgical maneuvers. Performance is analyzed for errors and total time of procedure. METHODS: Otolaryngology residents are introduced to robotic surgery with a tutorial on the usage of the da Vinci Surgical System (Intuitive Surgical, Inc., Sunnyvale, CA). Participants perform defined exercises accomplishing the following tasks: circular pin transfer, simultaneous bimanual carrying, precision bead drop, needle passing, and suture tying. Performance of these tasks can be quantitatively assessed. RESULTS: An educational program for teaching residents basic robotic skills can easily be introduced into a residency program. Resident progress in acquiring robotic surgical skills can be measured. The analysis of variance for composite score revealed statistically significant effects for task (F(4,24) = 8.11, P < .01) and trial (F(2,12) = 5.71, P < .01). CONCLUSIONS: Robotic surgery will likely become an integral part of otolaryngologic surgical practice. Training programs in robotic surgery need to be formally established in residency programs. We present a preliminary program for introducing robotic surgical skills in residency training.


Subject(s)
Internship and Residency , Otolaryngology/education , Robotics/education , Curriculum , Humans , Task Performance and Analysis
16.
Hum Mol Genet ; 17(17): 2723-37, 2008 Sep 01.
Article in English | MEDLINE | ID: mdl-18550655

ABSTRACT

Mutations in Mucolipin 1 (MCOLN1) have been linked to mucolipidosis type IV (MLIV), a lysosomal storage disease characterized by several neurological and ophthalmological abnormalities. It has been proposed that MCOLN1 might regulate transport of membrane components in the late endosomal-lysosomal pathway; however, the mechanisms by which defects of MCOLN1 function result in mental and psychomotor retardation remain largely unknown. In this study, we show constitutive activation of autophagy in fibroblasts obtained from MLIV patients. Accumulation of autophagosomes in MLIV cells was due to the increased de novo autophagosome formation and to delayed fusion of autophagosomes with late endosomes/lysosomes. Impairment of the autophagic pathway led to increased levels and aggregation of p62, suggesting that abnormal accumulation of ubiquitin proteins may contribute to the neurodegeneration observed in MLIV patients. In addition, we found that delivery of platelet-derived growth factor receptor to lysosomes is delayed in MCOLN1-deficient cells, suggesting that MCOLN1 is necessary for efficient fusion of both autophagosomes and late endosomes with lysosomes. Our data are in agreement with recent evidence showing that autophagic defects may be a common characteristic of many neurodegenerative disorders.


Subject(s)
Mucolipidoses/physiopathology , Autophagy , Endosomes/metabolism , Fibroblasts/cytology , Fibroblasts/metabolism , Humans , Lysosomes/metabolism , Receptors, Platelet-Derived Growth Factor/metabolism , TRPM Cation Channels/metabolism , Transient Receptor Potential Channels
17.
Exp Cell Res ; 314(5): 1177-91, 2008 Mar 10.
Article in English | MEDLINE | ID: mdl-18178185

ABSTRACT

Krp1, also called sarcosin, is a cardiac and skeletal muscle kelch repeat protein hypothesized to promote the assembly of myofibrils, the contractile organelles of striated muscles, through interaction with N-RAP and actin. To elucidate its role, endogenous Krp1 was studied in primary embryonic mouse cardiomyocytes. While immunofluorescence showed punctate Krp1 distribution throughout the cell, detergent extraction revealed a significant pool of Krp1 associated with cytoskeletal elements. Reduction of Krp1 expression with siRNA resulted in specific inhibition of myofibril accumulation with no effect on cell spreading. Immunostaining analysis and electron microscopy revealed that cardiomyocytes lacking Krp1 contained sarcomeric proteins with longitudinal periodicities similar to mature myofibrils, but fibrils remained thin and separated. These thin myofibrils were degraded by a scission mechanism distinct from the myofibril disassembly pathway observed during cell division in the developing heart. The data are consistent with a model in which Krp1 promotes lateral fusion of adjacent thin fibrils into mature, wide myofibrils and contribute insight into mechanisms of myofibrillogenesis and disassembly.


Subject(s)
Cytoskeletal Proteins/physiology , Muscle Proteins/physiology , Myocytes, Cardiac/cytology , Myofibrils/metabolism , Animals , Cells, Cultured , Cytoskeletal Proteins/genetics , Heart/embryology , Mice , Microscopy, Electron , Myofibrils/ultrastructure , RNA, Small Interfering/pharmacology
18.
J Clin Invest ; 117(12): 3742-52, 2007 Dec.
Article in English | MEDLINE | ID: mdl-18037990

ABSTRACT

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder associated with ciliary defects and situs inversus totalis, the complete mirror image reversal of internal organ situs (positioning). A variable incidence of heterotaxy, or irregular organ situs, also has been reported in PCD patients, but it is not known whether this is elicited by the PCD-causing genetic lesion. We studied a mouse model of PCD with a recessive mutation in Dnahc5, a dynein gene commonly mutated in PCD. Analysis of homozygous mutant embryos from 18 litters yielded 25% with normal organ situs, 35% with situs inversus totalis, and 40% with heterotaxy. Embryos with heterotaxy had complex structural heart defects that included discordant atrioventricular and ventricular outflow situs and atrial/pulmonary isomerisms. Variable combinations of a distinct set of cardiovascular anomalies were observed, including superior-inferior ventricles, great artery alignment defects, and interrupted inferior vena cava with azygos continuation. The surprisingly high incidence of heterotaxy led us to evaluate the diagnosis of PCD. PCD was confirmed by EM, which revealed missing outer dynein arms in the respiratory cilia. Ciliary dyskinesia was observed by videomicroscopy. These findings show that Dnahc5 is required for the specification of left-right asymmetry and suggest that the PCD-causing Dnahc5 mutation may also be associated with heterotaxy.


Subject(s)
Ciliary Motility Disorders/pathology , Dyneins/genetics , Heart Defects, Congenital/ultrastructure , Mutation , Situs Inversus/ultrastructure , Animals , Cilia/genetics , Cilia/ultrastructure , Ciliary Motility Disorders/genetics , Ciliary Motility Disorders/physiopathology , Disease Models, Animal , Genes, Recessive , Heart Defects, Congenital/genetics , Heart Defects, Congenital/pathology , Humans , Lung/physiopathology , Lung/ultrastructure , Mice , Mice, Mutant Strains , Myocardium/ultrastructure , Situs Inversus/genetics , Situs Inversus/physiopathology , Vena Cava, Inferior/physiopathology , Vena Cava, Inferior/ultrastructure
19.
Respir Med ; 101(1): 43-7, 2007 Jan.
Article in English | MEDLINE | ID: mdl-16753290

ABSTRACT

Antigen detection is a useful adjunct for the diagnosis of histoplasmosis. The purpose of this study was to evaluate antigen detection in bronchoalveolar lavage (BAL) fluid using an improved second-generation Histoplasma antigen assay. Antigen was detected in 16 of 19 (84%) cases of histoplasmosis and 5 of 6 (83.3%) blastomycosis cases using the second-generation assay vs. 13 of 19 (68%) and 4 of 6 (66.7%), respectively, in the original assay. Ten-fold concentration permitted detection of antigen in an additional case of histoplasmosis and another with blastomycosis, for an overall sensitivity of 23 of 25 (92.0%). Specificity was 98.2% in both assays in controls with other pulmonary infections. These findings support the diagnostic utility of the second-generation assay in patients with pulmonary histoplasmosis and blastomycosis.


Subject(s)
Antigens, Fungal/analysis , Blastomycosis/diagnosis , Bronchoalveolar Lavage Fluid/immunology , Histoplasmosis/diagnosis , Lung Diseases, Fungal/diagnosis , Chi-Square Distribution , Enzyme-Linked Immunosorbent Assay/methods , Female , Histoplasma/immunology , Humans , Immunocompromised Host , Liver Transplantation , Middle Aged , Statistics, Nonparametric
20.
J Exp Zool A Comp Exp Biol ; 303(11): 927-45, 2005 Nov 01.
Article in English | MEDLINE | ID: mdl-16217807

ABSTRACT

Trichuris muris is a large metazoan pathogen that has been proposed to live intracellularly within living host intestinal epithelial cells. We sought to determine how Trichuris bores its way through the mucosal epithelium and to elucidate the parasite strategies for taking advantage of this intracellular niche. Since the apical surface of the mucosal epithelium is stabilized by the actin cytoskeleton and cell junctions, it remains intact over the worm following its entry into cells. In contrast, non-stabilized lateral membranes of the host epithelial cells are ruptured and cells are killed to form an inert syncytial tunnel. The ventral surface of the nematode worm is studded by pores that overlie bacillary cells; these pores penetrate through the cuticle and are in direct contact with host cytoplasm. From scanning electron micrographs of isolated worms, we calculate that each adult contains approximately 50,000 bacillary cells. The apical surface of the bacillary cells is extensively folded into plicae 40 nm in diameter, thereby increasing the surface area many-fold. Bacillary cells lack organelles for enzyme synthesis and secretion and fail to export protons. However, by confocal light microscopy it was observed that fluorescent macromolecules in excess of 100,000 Da can penetrate into the pores. Taken together, we conclude that the bacillary cells are essential for living inside host epithelium and function predominantly in absorption of soluble molecules from the host mucosal cytoplasm, in essence behaving as an external gut epithelium that is protected from abrasion by the cuticle that surrounds the openings of the bacillary cells.


Subject(s)
Adaptation, Physiological/physiology , Intestinal Mucosa/parasitology , Mice/parasitology , Trichuris/cytology , Trichuris/ultrastructure , Animals , Fluorescent Dyes , Host-Parasite Interactions , Mice, Inbred BALB C , Microscopy, Confocal , Microscopy, Electron , Specific Pathogen-Free Organisms , Trichuris/physiology
SELECTION OF CITATIONS
SEARCH DETAIL
...