ABSTRACT
The intrinsic properties of superconductors enable the direct determination of the absolute Seebeck coefficient at low temperature due to the disappearance of the Seebeck effect to obey the Meissner effect. We report a precision absolute Seebeck coefficient measurement for the fine Pt sample determined using the high-Tc YBa2Cu3O7-x (YBCO) superconductor as a reference and an analysis of the measurement uncertainty. To make a precision measurement and aid in the verification of the uncertainty components, we developed a cryostat system that enables temperature control in a stable manner. The expected performance of the reference superconductor yielded a zero value well below Tc, which was validated by a superconductor-superconductor thermocouple experiment. Uncertainty analysis shows that the main limiting factor for this measurement is the accuracy of the temperature difference measurement using the resistance temperature sensors, along with its analog noise. We obtained values of S = 5.6 ± 0.2 µV/K with a relative expanded uncertainty of 3% at 80 K and precisely compared the Pt value with that determined by the high-Tc Bi2Sr2Ca2Cu3O8+δ (Bi-2223) superconductor, which has a higher Tc. We found that there was no difference between the Seebeck coefficient values obtained from the YBCO and Bi-2223 references up to its Tc within the expanded measurement uncertainties of 0.3 µV/K (2σ). These results provide accurate validation that the high-Tc superconductor is a useful reference up to the liquid nitrogen temperature.
ABSTRACT
BACKGROUND: Contact precautions are required to prevent transmission of multi-drug-resistant organisms; however, reports on adherence rates vary. This study used video monitoring to evaluate adherence to the use of personal protective equipment (PPE) by different types of healthcare workers. METHODS: This observational study was conducted in a 781-bed tertiary hospital from July 2016 to March 2017. Cameras were installed in areas where staff don PPE. Infection control teams observed the videos and assessed adherence rates. RESULTS: In total, 1097 opportunities for donning PPE were observed. Most staff observed were nurses and nursing assistants (Ns/Nsas) (880/1097, 80.2%). Overall, the adherence rate to appropriate PPE use was 34.0%. The adherence rate among Ns/Nsas was lower (239/858, 27.9%) compared with infectious disease doctors (18/18, 100%) and cleaning staff (42/49, 85.7%). The adherence rate for PPE use for Clostridium difficile infection (CDI) with toxin detection was significantly higher than that for CDI without toxin detection and multi-drug-resistant organisms (P<0.001 for both). The adherence rate for patients with an independent functional status was higher than that for patients with a dependent functional status (P=0.018). The adherence rate was lower in the intensive care unit (ICU) than in non-ICU wards (27.6% vs 36.5%; P=0.006). CONCLUSION: Video monitoring is a useful tool for monitoring adherence to PPE use, facilitating observation of more PPE opportunities than direct observation. Adherence to contact precautions varied by occupation; however, overall adherence was insufficient. The lower adherence rate in nurses might be due to more frequent care visits.
Subject(s)
Cross Infection/prevention & control , Disease Transmission, Infectious/prevention & control , Guideline Adherence , Health Personnel , Infection Control/methods , Humans , Tertiary Care Centers , Video RecordingABSTRACT
OBJECTIVE: To investigate the prevalence of bacterial co-infection and its effect on early mortality among hospitalised human immunodeficiency virus (HIV) negative pulmonary tuberculosis (PTB) patients in Manila, the Philippines. DESIGN: A prospective observational study was conducted at a national infectious disease hospital. HIV-negative PTB patients aged î¶13 years hospitalised from November to December 2011 and from December 2012 to May 2013 were enrolled. Sputum samples were tested for Mycobacterium tuberculosis and six respiratory bacterial pathogens using polymerase chain reaction (PCR). RESULTS: Of 466 patients, 228 (48.9%) were TB-PCR-positive. Overall, bacterial pathogens in purulent sputum were detected in 135 (29.0%) patients: Haemophilus influenzae was the most common bacterium (21.2%), followed by Streptococcus pneumoniae (7.9%). The prevalence of bacterial co-infection did not differ between TB-PCR-positive and -negative patients. A total of 92 (19.7%) patients died within 2 weeks. Bacterial co-infection was significantly associated with an increased risk of 2-week mortality among TB-PCR-positive patients (adjusted risk ratio [aRR] 1.67, 95%CI 1.03-2.72). This association was also observed but did not reach statistical significance among TB-PCR-negative patients (aRR1.7, 95%CI 0.95-3.02). CONCLUSION: Bacterial co-infection is common and contributes to an increased risk of early mortality among HIV-negative PTB patients.
Subject(s)
Bacterial Infections/epidemiology , Mycobacterium tuberculosis/isolation & purification , Tuberculosis, Pulmonary/epidemiology , Adolescent , Adult , Bacterial Infections/microbiology , Coinfection , Female , Hospitalization , Humans , Male , Middle Aged , Philippines/epidemiology , Polymerase Chain Reaction , Prevalence , Prospective Studies , Sputum/microbiology , Tuberculosis, Pulmonary/diagnosis , Tuberculosis, Pulmonary/mortality , Young AdultABSTRACT
BACKGROUND AND PURPOSE: Vasopressin V1B receptor antagonists may be effective for the treatment of depression and anxiety and the objective of this study was to characterize the pharmacological profiles of two newly synthesized arginine vasopressin receptor 1B (V1B receptor) antagonists, TASP0233278 and TASP0390325. EXPERIMENTAL APPROACH: We investigated the in vitro profiles of TASP0233278 and TASP0390325. In addition, the effect of TASP0390325 on the increase in plasma adrenocorticotropic hormone (ACTH) levels induced by corticotropin-releasing factor (CRF)/desmopressin (dDAVP) was investigated. We also investigated the antidepressant and anxiolytic profiles of TASP0233278 and TASP0390325 in animal models. KEY RESULTS: Both TASP0233278 and TASP0390325 showed a high affinity and potent antagonist activity for V1B receptors. Oral administration of TASP0390325 antagonized the increase in plasma ACTH levels induced by CRF/dDAVP in rats, indicating that TASP0390325 blocks the anterior pituitary V1B receptor in vivo. Oral administration of TASP0233278 or TASP0390325 also exerted antidepressant effects in two models of depression (a forced swimming test and an olfactory bulbectomy model). Moreover, TASP0233278 improved depressive-like behaviour induced by repeated treatment with corticosterone, a model that has been shown to be resistant to treatment with currently prescribed antidepressants. In addition to depression models, TASP0233278 or TASP0390325 exerted anxiolytic effects in several anxiety models (social interaction, elevated plus-maze, stress-induced hyperthermia, separation-induced ultrasonic vocalization and sodium lactate-induced panic-like responses in panic-prone rats). CONCLUSION: TASP0233278 and TASP0390325 are potent and orally active V1B receptor antagonists with antidepressant and anxiolytic activities in rodents.
Subject(s)
Anti-Anxiety Agents/pharmacology , Antidepressive Agents/pharmacology , Antidiuretic Hormone Receptor Antagonists/pharmacology , Depression/drug therapy , Indoles/pharmacology , Proline/analogs & derivatives , Pyridines/pharmacology , Pyrimidinones/pharmacology , Receptors, Vasopressin/metabolism , Administration, Oral , Animals , Anti-Anxiety Agents/administration & dosage , Anti-Anxiety Agents/chemistry , Antidepressive Agents/administration & dosage , Antidepressive Agents/chemistry , Antidiuretic Hormone Receptor Antagonists/administration & dosage , Antidiuretic Hormone Receptor Antagonists/chemistry , CHO Cells , Corticosterone , Cricetulus , Depression/chemically induced , Disease Models, Animal , Humans , Indoles/administration & dosage , Indoles/chemistry , Male , Mice , Proline/administration & dosage , Proline/chemistry , Proline/pharmacology , Pyridines/administration & dosage , Pyridines/chemistry , Pyrimidinones/administration & dosage , Pyrimidinones/chemistry , Rats , Rats, Sprague-Dawley , Rats, WistarABSTRACT
OBJECTIVE: To determine the mortality rate and risk factors for in-hospital death among hospitalised human immunodeficiency virus (HIV) negative tuberculosis (TB) patients in poor urban areas in the Philippines. DESIGN: A cross-sectional study was conducted at a national infectious disease hospital in Manila City. The target population was patients aged ≥ 13 years with all forms of HIV-negative TB admitted from October to December 2009. Demographic and clinical information was collected from medical charts, and risk of in-hospital death was measured. RESULTS: Of 407 HIV-negative TB patients, four were excluded due to missing records, and 403 were included in the analysis. The majority were poor urban residents (90%), and 66% were males. Overall, 37.5% of hospitalised patients died in the hospital (151/403), 30% of whom died before the third day of hospitalisation. Risk factor analysis demonstrated that complications of bacterial pneumonia had the greatest effect on in-hospital death (aOR 4.53, 95%CI 2.65-7.72), followed by anorexia (aOR 3.01, 95%CI 1.55-5.84), anaemia (haemoglobin <10 g/dl, aOR 2.35, 95%CI 1.34-4.13) and older age (aged ≥ 50 years, aOR 1.85, 95%CI 1.08-3.17). The presence of haemoptysis (aOR 0.44, 95%CI 0.25-0.80) was associated with improved survival. CONCLUSION: Mortality among hospitalised HIV-negative TB patients was extremely high in poor urban areas in the Philippines.
Subject(s)
Hospital Mortality , Hospitalization/statistics & numerical data , Poverty Areas , Tuberculosis/mortality , Urban Health/statistics & numerical data , Adolescent , Adult , Age Factors , Comorbidity , Cross-Sectional Studies , Female , Humans , Logistic Models , Male , Middle Aged , Multivariate Analysis , Odds Ratio , Philippines/epidemiology , Residence Characteristics , Retrospective Studies , Risk Factors , Time Factors , Tuberculosis/diagnosis , Tuberculosis/therapy , Young AdultABSTRACT
Metastatic pulmonary calcification, defined as calcium deposition in the intact lung, is commonly seen in patients with chronic renal failure, and it is known to be a benign clinical condition when detected by chance in an asymptomatic patient. Here we report the case of a 33-year-old woman who developed rapid and aggressive metastatic pulmonary calcification shortly after a living donor kidney transplantation, which induced acute antibody-mediated rejection. The patient's metastatic pulmonary calcification was successfully improved by extensive treatment for graft rejection, the correction of her accompanying primary hyperparathyroidism, and medical treatment with a bisphosphonate and sodium thiosulfate. Aggressive pulmonary calcification is reported as a rare complication seen in patients who have undergone a failed renal transplantation. A failed renal graft and accompanying secondary hyperparathyroidism seem to accelerate metastatic calcification. Most of the patients who develop aggressive pulmonary calcification suffer from the rapid progression of dyspnea and occasionally fever, and they die of respiratory failure. Pulmonary calcification should be considered in a patient developing dyspnea and unexplained pulmonary infiltrate, especially in the context of renal graft rejection; otherwise the prognosis of the patient will be very poor.
Subject(s)
Calcinosis , Hyperparathyroidism, Primary/surgery , Kidney Transplantation/adverse effects , Living Donors , Lung/pathology , Adult , Calcinosis/diagnostic imaging , Female , Humans , Hyperparathyroidism, Primary/pathology , Renal Insufficiency/surgery , Tomography, X-Ray ComputedSubject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Dog Diseases/immunology , Endogenous Retroviruses/immunology , Parvoviridae Infections/veterinary , Animals , Cats , Cell Line , Dog Diseases/prevention & control , Dog Diseases/virology , Dogs , Endogenous Retroviruses/physiology , Guinea Pigs , Parvoviridae Infections/immunology , Parvoviridae Infections/prevention & control , Parvoviridae Infections/virology , Parvovirus, Canine/immunology , Parvovirus, Canine/physiology , Viral Vaccines/immunologyABSTRACT
The aim of this study was to evaluate the sensation of each tooth type at the cortical level. The tactical sensation from teeth plays an important role in controlling the masticatory system. However, the role of each tooth type has not been determined. Functional near-infrared spectroscopy (fNIRS) was used to detect changes in cerebral blood flow in the somatosensory cortex of 12 healthy volunteers. Painless vibrotactile stimuli were applied to 8 teeth (left maxillary and mandibular incisors, canines, 1(st) premolars, or 1(st) molars). The somatosensory cortex was activated during stimulation of all teeth. A comparison of cortical activation revealed significantly greater activation during stimulation of the maxillary and mandibular first molars. However, no significant differences were seen between any other teeth. These results indicate that the first molar is the most sensitive tooth type at the cortical level, and provide basic data on the relationship between input from individual tooth type and brain activation. These data could be useful for understanding the neural mechanisms of individual tooth types.
Subject(s)
Somatosensory Cortex/physiology , Tooth/physiology , Touch/physiology , Adult , Bicuspid/physiology , Cerebrovascular Circulation/physiology , Cuspid/physiology , Female , Humans , Incisor/physiology , Male , Mandible , Maxilla , Molar/physiology , Oxyhemoglobins/metabolism , Physical Stimulation/methods , Somatosensory Cortex/blood supply , Spectroscopy, Near-Infrared/instrumentation , Spectroscopy, Near-Infrared/methods , Vibration , Young AdultABSTRACT
Hepatitis C virus (HCV) infects and associates with B cells, leading to abnormal B-cell activation and development of lymphoproliferative and autoimmune disorders. This immune perturbation may in turn be associated with the resistance of HCV against the host immune system. The objective of this study was to analyse the effects of HCV infection of B cells on the efficacy of interferon (IFN)-based therapy. The study enrolled 102 patients with chronic hepatitis C who were treated with pegylated IFN plus ribavirin. HCV RNA titres in B cells were compared in patients with rapid viral responder (RVR) vs non-RVR, sustained viral responder (SVR) vs non-SVR and null viral responder (NVR) vs VR. The levels of HCV RNA in B cells were significantly higher in non-RVR, non-SVR and NVR groups. Association between the therapy outcome and the positive B-cell HCV RNA was also investigated in relation to other known viral and host factors. Multivariable analyses showed that the positive B-cell HCV RNA and the minor single-nucleotide polymorphism near the IL28B gene (rs8099917) were independent factors associated with NVR in patients infected with HCV genotype 1. When these two factors were combined, the sensitivity, specificity, positive and negative predictive values for NVR were 92.3%, 98.2%, 92.3% and 98.2%, respectively. Genotype 1 and the presence of one or no mutations in the IFN-sensitivity determining region were associated with higher levels of B-cell HCV RNA. B-cell-tropic HCV appears to have an IFN-resistant phenotype. B-cell HCV RNA positivity is a predictive factor for resistance to IFN-based therapy.
Subject(s)
Antiviral Agents/administration & dosage , B-Lymphocytes/virology , Drug Resistance, Viral , Hepacivirus/drug effects , Hepacivirus/physiology , Interferons/administration & dosage , Viral Tropism , Adult , Aged , Female , Genotype , Hepacivirus/genetics , Hepacivirus/isolation & purification , Humans , Interleukins/genetics , Male , Middle Aged , Polymorphism, Single Nucleotide , RNA, Viral/analysis , RNA, Viral/genetics , Ribavirin/administration & dosage , Treatment OutcomeABSTRACT
A silver-containing hydroxyapatite (Ag-HA) coating has been developed using thermal spraying technology. We evaluated the osteoconductivity of this coating on titanium (Ti) implants in rat tibiae in relation to bacterial infection in joint replacement. At 12 weeks, the mean affinity indices of bone formation of a Ti, an HA, a 3%Ag-HA and a 50%Ag-HA coating were 97.3%, 84.9%, 81.0% and 40.5%, respectively. The mean affinity indices of bone contact of these four coatings were 18.8%, 83.7%, 77.2% and 40.5%, respectively. The indices of bone formation and bone contact around the implant of the 3%Ag-HA coating were similar to those of the HA coating, and no significant differences were found between them (bone formation, p = 0.99; bone contact, p = 0.957). However, inhibition of bone formation was observed with the 50%Ag-HA coating. These results indicate that the 3%Ag-HA coating has low toxicity and good osteoconductivity, and that the effect of silver toxicity on osteoconductivity depends on the dose.
Subject(s)
Anti-Bacterial Agents/pharmacology , Bone Regeneration/drug effects , Durapatite/pharmacology , Joint Prosthesis , Oxides/pharmacology , Silver Compounds/pharmacology , Animals , Body Weight/drug effects , Bone Regeneration/physiology , Coated Materials, Biocompatible , Male , Prosthesis-Related Infections/prevention & control , Rats , Rats, Sprague-Dawley , Silver/blood , Tibia/surgery , TitaniumABSTRACT
A 69-year-old female visited our hospital because of dyspnea. Chest X-ray showed an abnormal shadow in the right lower lung field. Chest computed tomography (CT) showed a round, well-circumscribed, homogenous subpleural nodle of 8 mm in diameter in the right lower lobe, which had no calcification and no pleural indentation. Bronchofiber scope, abdominal CT, brain magnetic resonance imaging (MRI), bone scintigraphy could not establish definitive diagnosis. Scince the possibility of malignancy could not be excluded throughout, video-assisted thoracoscopic surgery was performed to obtain confirmed diagnosis. Pathological examination revealed non-chondromatous hamartoma of the lung. Non-chondromatous hamartoma should be considered in the differential diagnosis of pulmonary nodles. We report a rare case of non-chondromatous hamartoma.
Subject(s)
Hamartoma/pathology , Lung Diseases/pathology , Aged , Female , HumansABSTRACT
Mammalian corticogenesis occurs through a complex process that includes neurogenesis, in which neural progenitor cells proliferate, differentiate, and migrate. It has been reported recently that neurogenesis occurs in the subventricular zone (SVZ), a region previously thought to be the primary site of gliogenesis. It has been recognized that in the SVZ, intermediate progenitor cells, derived from radial glial cells that are multipotent neural stem cells, produce only neurons. However, the molecular mechanisms underlying the regulation of neural stem cells and intermediate progenitor cells as well as their contribution to overall corticogenesis remain unknown. The docking protein FRS2alpha is a major mediator of signaling by means of FGFs and neurotrophins. FRS2alpha mediates many of its pleiotropic cellular responses by recruiting the adaptor protein Grb2 and the protein tyrosine phosphatase Shp2 upon ligand stimulation. Here, we report that targeted disruption of Shp2-binding sites in FRS2alpha leads to severe impairment in cerebral cortex development in mutant mice. The defect in corticogenesis appears to be due at least in part to abnormalities in intermediate progenitor cells. Genetic evidence is provided that FRS2alpha plays critical roles in the maintenance of intermediate progenitor cells and in neurogenesis in the cerebral cortex. Moreover, FGF2-responsive neurospheres, which are cell aggregates derived from neural stem/progenitor cells (NSPCs), from FRS2alpha mutant mice were smaller than those of WT mice. However, mutant NSPCs were able to self-renew, demonstrating that Shp2-binding sites on FRS2alpha play an important role in NSPC proliferation but are dispensable for NSPC self-renewing capacity after FGF2 stimulation.
Subject(s)
Cerebral Cortex/growth & development , Intracellular Signaling Peptides and Proteins/metabolism , Membrane Proteins/metabolism , Neurons/cytology , Protein Tyrosine Phosphatases/metabolism , Receptor, Fibroblast Growth Factor, Type 2/physiology , Stem Cells/cytology , Animals , Binding Sites , Cell Proliferation , Cells, Cultured , Cerebral Cortex/cytology , Embryo, Mammalian , Immunohistochemistry , Intracellular Signaling Peptides and Proteins/physiology , Membrane Proteins/physiology , Mice , Mice, Mutant Strains , Protein Tyrosine Phosphatase, Non-Receptor Type 11 , Protein Tyrosine Phosphatases/physiologyABSTRACT
Between October 1996 and June 2003, endovascular stent graft repair was performed in 87 patients with descending thoracic aortic aneurysms, graft replacement was performed in 24 patients with thoracoabdominal aortic aneurysms, and endovascular stent graft repair with concomitant surgical bypass of abdominal visceral arteries was performed in 3 patients with thoracoabdominal aortic aneurysms. The retrievable stent graft was inserted and evoked spinal cord potential were monitored in order to predict spinal cord ischemia for stent graft repair. There was no paraplegia or hospital death, although 3 patients had paraparesis in stent graft repair. Two of the 3 patients with paraparesis made a full neurologic recovery. There were no cases of paraplegia or paraparesis in surgical operations with thoracoabdominal aortic aneurysm. The concomitant surgical procedure was a good technique for patients in whom cardiopulmonary bypass could not be used. Our results of stent graft repair and surgical operation for descending thoracic or thoracoabdominal aortic aneurysms were acceptable. The retrievable stent graft was useful for prediction of spinal cord ischemia before endovascular stent graft repair of descending thoracic or thoracoabdominal aortic aneurysm.
Subject(s)
Aortic Aneurysm, Abdominal/surgery , Aortic Aneurysm, Thoracic/surgery , Evoked Potentials/physiology , Intraoperative Complications/diagnosis , Monitoring, Intraoperative/methods , Spinal Cord Ischemia/diagnosis , Spinal Cord/physiopathology , Stents , Adult , Aged , Aged, 80 and over , Female , Humans , Intraoperative Complications/prevention & control , Male , Middle Aged , Spinal Cord Ischemia/prevention & control , Vascular Surgical Procedures/methodsABSTRACT
Endogenous neural stem/progenitor cells (NSPCs) have recently been shown to differentiate exclusively into astrocytes, the cells that are involved in glial scar formation after spinal cord injury (SCI). The microenvironment of the spinal cord, especially the inflammatory cytokines that dramatically increase in the acute phase at the injury site, is considered to be an important cause of inhibitory mechanism of neuronal differentiation following SCI. Interleukin-6 (IL-6), which has been demonstrated to induce NSPCs to undergo astrocytic differentiation selectively through the JAK/STAT pathway in vitro, has also been demonstrated to play a critical role as a proinflammatory cytokine and to be associated with secondary tissue damage in SCI. In this study, we assessed the efficacy of rat anti-mouse IL-6 receptor monoclonal antibody (MR16-1) in the treatment of acute SCI in mice. Immediately after contusive SCI with a modified NYU impactor, mice were intraperitoneally injected with a single dose of MR16-1 (100 microg/g body weight), the lesions were assessed histologically, and the functional recovery was evaluated. MR16-1 not only suppressed the astrocytic diffentiation-promoting effect of IL-6 signaling in vitro but inhibited the development of astrogliosis after SCI in vivo. MR16-1 also decreased the number of invading inflammatory cells and the severity of connective tissue scar formation. In addition, we observed significant functional recovery in the mice treated with MR16-1 compared with control mice. These findings suggest that neutralization of IL-6 signaling in the acute phase of SCI represents an attractive option for the treatment of SCI.
Subject(s)
Antibodies/therapeutic use , Astrocytes/drug effects , Receptors, Interleukin-6/immunology , Recovery of Function , Spinal Cord Injuries/therapy , Analysis of Variance , Animals , Behavior, Animal , Blotting, Western/methods , Bromodeoxyuridine/metabolism , CD11b Antigen/metabolism , Cell Count/methods , Cells, Cultured , DNA-Binding Proteins/metabolism , Disease Models, Animal , ELAV Proteins , Female , Glial Fibrillary Acidic Protein/metabolism , Immunohistochemistry/methods , In Vitro Techniques , Interleukin-6/pharmacology , Locomotion/drug effects , Male , Mice , Mice, Inbred C57BL , Nerve Tissue Proteins/metabolism , Psychomotor Performance/drug effects , RNA-Binding Proteins/metabolism , Receptors, Interleukin-6/antagonists & inhibitors , STAT3 Transcription Factor , Spinal Cord Injuries/metabolism , Spinal Cord Injuries/pathology , Staining and Labeling , Trans-Activators/metabolismABSTRACT
A 78-year-old man had a descending thoracic aortic aneurysm with left main coronary artery disease. Combined beating heart coronary artery bypass and endovascular thoracic aortic aneurysm repair was performed without cardiopulmonary bypass. The left anterior descending artery and the obtuse marginal branch of the left circumflex artery were revascularized through a left antero-lateral small thoracotomy. The aneurysm was excluded with stent grafts through a small femoral incision. This combined less invasive procedure is a promising approach providing better surgical results in patients with thoracic aortic aneurysm and severe coronary artery disease.
Subject(s)
Aortic Aneurysm, Thoracic/surgery , Coronary Artery Bypass/methods , Coronary Disease/surgery , Stents , Aged , Aortic Aneurysm, Thoracic/complications , Aortic Aneurysm, Thoracic/diagnostic imaging , Cardiac Catheterization , Combined Modality Therapy , Coronary Angiography , Coronary Disease/complications , Coronary Disease/diagnostic imaging , Follow-Up Studies , Humans , Male , Minimally Invasive Surgical Procedures/methods , Risk Assessment , Severity of Illness Index , Thoracotomy/methods , Treatment OutcomeABSTRACT
Recent studies have shown that neurogenesis is enhanced after hypoxia and that erythropoietin (EPO), an inducible cytokine, is produced in the brain as part of the intrinsic hypoxia response. Thus, we asked whether EPO might regulate neurogenesis by forebrain neural stem cells (NSCs). We found that EPO receptors are expressed in the embryonic germinal zone during neurogenesis as well as in the adult subventricular zone, which continues to generate neurons throughout adulthood. Cultured NSCs exposed to a modest hypoxia produced two- to threefold more neurons, which was associated with an elevation in EPO gene expression. The enhanced neuron production attributable to hypoxia was mimicked by EPO and blocked by coadministration of an EPO neutralizing antibody. EPO appears to act directly on NSCs, promoting the production of neuronal progenitors at the expense of multipotent progenitors. EPO infusion into the adult lateral ventricles resulted in a decrease in the numbers of NSCs in the subventricular zone, an increase in newly generated cells migrating to the olfactory bulb, and an increase in new olfactory bulb interneurons. Infusion of anti-EPO antibodies had the opposite effect: an increase in the number of NSCs in the subventricular zone and a decrease in the number of newly generated cells migrating to the bulb. These findings suggest that EPO is an autocrine-paracrine factor, capable of regulating the production of neuronal progenitor cells by forebrain NSCs.
Subject(s)
Erythropoietin/metabolism , Neurons/metabolism , Prosencephalon/metabolism , Stem Cells/metabolism , Active Transport, Cell Nucleus/drug effects , Animals , Antibodies/administration & dosage , Antibodies/pharmacology , Autocrine Communication/physiology , Basic Helix-Loop-Helix Transcription Factors , Cell Count , Cell Division/drug effects , Cell Division/physiology , Cell Hypoxia/physiology , Cell Movement/drug effects , Cells, Cultured , DNA-Binding Proteins/biosynthesis , Epidermal Growth Factor/pharmacology , Erythropoietin/antagonists & inhibitors , Erythropoietin/pharmacology , Injections, Intraventricular , Interneurons/cytology , Interneurons/drug effects , Lateral Ventricles/cytology , Lateral Ventricles/drug effects , Lateral Ventricles/physiology , Mice , NF-kappa B/antagonists & inhibitors , NF-kappa B/metabolism , Neurons/cytology , Neurons/drug effects , Olfactory Bulb/cytology , Olfactory Bulb/drug effects , Paracrine Communication/physiology , Peptides/pharmacology , Prosencephalon/cytology , Prosencephalon/embryology , Spheroids, Cellular/cytology , Spheroids, Cellular/drug effects , Stem Cells/cytology , Stem Cells/drug effects , Transcription Factors/biosynthesisABSTRACT
The adult mouse forebrain, which exhibits substantial ongoing cell genesis, contains self-renewing multipotent neural stem cells that respond to epidermal growth factor (EGF), but the adult spinal cord, which exhibits limited cell genesis, does not. Spinal cord development is a process characterized by defined periods of cell histogenesis. Thus, in the present study we asked whether EGF-responsive neural stem cells are present within the spinal cord during development. At embryonic day (E) 11, subsequent to the onset of neurogenesis, only fibroblast growth factor (FGF) receptors and FGF-2 (requiring heparan sulphate)-responsive stem cells are present in the spinal cord. Between E12 and 14, at the peak of spinal cord neurogenesis and the onset of gliogenesis, EGF receptors appear along with clonally derived highly expandable EGF-responsive neural stem cells. Following the cessation of cell histogenesis, the adult spinal cord is largely devoid of both EGF receptors and EGF-responsive stem cells. On the other hand, the FGF receptor1c subtype and multipotent FGF-2-responsive neural stem cells are present in early development and in the adult. The order of appearance of spinal cord neural stem cells and in vitro lineage analysis suggests that a more primitive FGF-2-responsive stem cell produces the EGF-responsive stem cell. These findings suggest that EGF-responsive neural stem cells appear transiently in the spinal cord, during the peak period of cell histogenesis, but are no longer present in the relatively quiescent adult structure.
Subject(s)
Epidermal Growth Factor/physiology , Neurons/physiology , Spinal Cord/cytology , Spinal Cord/embryology , Stem Cells/physiology , Animals , Cell Count , Cells, Cultured , Clone Cells , Fibroblast Growth Factor 2/pharmacology , Immunohistochemistry , Mice , Phenotype , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
The cytokines that signal through the common receptor subunit gp130, including ciliary neurotrophic factor (CNTF), interleukin-6, leukemia inhibitory factor (LIF) and oncostatin M, have pleiotropic functions in CNS development. Given the restricted expression domain of the CNTF receptor alpha (CNTFR) in the developing forebrain germinal zone and adult forebrain periventricular area, we have examined the putative role of CNTFR/LIFR/gp130-mediated signaling in regulating forebrain neural stem cell fate in vivo and in vitro. Analysis of LIFR-deficient mice revealed that a decreased level of LIFR expression results in a reduction in the number of adult neural stem cells. In adult LIFR heterozygote (+/-) mice, the number of neural stem cells and their progeny in the forebrain subependyma and TH-immunoreactive neurons in the olfactory bulb were significantly reduced. Intraventricular infusion of CNTF into the adult mouse forebrain, in the absence or presence of epidermal growth factor (EGF), enhanced self-renewal of neural stem cells in vivo. Analyses of EGF-responsive neural stem cells proliferating in vitro found that CNTF inhibits lineage restriction of neural stem cells to glial progenitors, which in turn results in enhanced expansion of stem cell number. These results suggest that CNTFR/LIFR/gp130-mediated signaling supports the maintenance of forebrain neural stem cells, likely by suppressing restriction to a glial progenitor cell fate.
Subject(s)
Neurons/metabolism , Prosencephalon/metabolism , Receptor, Ciliary Neurotrophic Factor/metabolism , Stem Cells/metabolism , Animals , Antigens, CD/metabolism , Cell Count , Cell Differentiation/drug effects , Cell Lineage , Cells, Cultured , Ciliary Neurotrophic Factor/metabolism , Ciliary Neurotrophic Factor/pharmacology , Cytokine Receptor gp130 , Epidermal Growth Factor/pharmacology , Heterozygote , Injections, Intraventricular , Leukemia Inhibitory Factor Receptor alpha Subunit , Macromolecular Substances , Membrane Glycoproteins/metabolism , Mice , Mice, Knockout , Neuroglia/cytology , Neuroglia/metabolism , Neurons/cytology , Olfactory Bulb/cytology , Olfactory Bulb/metabolism , Prosencephalon/cytology , Receptor, Ciliary Neurotrophic Factor/genetics , Receptors, Cytokine/deficiency , Receptors, Cytokine/genetics , Receptors, OSM-LIF , Signal Transduction/physiology , Stem Cells/cytology , Stem Cells/drug effects , Tyrosine 3-Monooxygenase/biosynthesisABSTRACT
The mechanism of stent thrombosis was evaluated by a flow chamber model. A Palmaz-Schatz stent was placed on glass surfaces coated with type I collagen in a parallel-plate flow chamber. Platelets were rendered fluorescent with mepacrine and whole blood was perfused through the chamber. Platelet thrombi formed around the implanted stents were continuously recorded by epi-fluorescent video-microscopy. Platelet thrombi appeared on the collagen surface within a few minutes in the absence of function blocking monoclonal antibodies. Antibody blocking vWF interaction with GP Ib alpha completely inhibited the platelet thrombi around the stent, but had no effect on platelet thrombus formation in the space between the stents and collagen, while both were inhibited by anti-GP IIb/IIIa. Our results suggest that two distinct mechanisms, one mediated by vWF interaction with GP Ib alpha occurring at high shear rates, and the other mediated exclusively by GP IIb/IIIa occurring at low shear rates, are involved in the process of platelet thrombus formation in the presence of stents.