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Proceedings of the National Academy of... Aug 2022The embedded contact homology (ECH) capacities are a sequence of numerical invariants of symplectic four-manifolds that give (sometimes sharp) obstructions to symplectic...
The embedded contact homology (ECH) capacities are a sequence of numerical invariants of symplectic four-manifolds that give (sometimes sharp) obstructions to symplectic embeddings. These capacities are defined using embedded contact homology, and establishing their basic properties currently requires Seiberg-Witten theory. In this paper we define a sequence of symplectic capacities in four dimensions using only basic notions of holomorphic curves. The capacities satisfy the same basic properties as ECH capacities and agree with the ECH capacities for the main examples for which the latter have been computed, namely convex and concave toric domains. The capacities are also useful for obstructing symplectic embeddings into closed symplectic four-manifolds. This work is inspired by a recent preprint of McDuff and Siegel [D. McDuff, K. Siegel, [Preprint] (2021)], giving a similar elementary alternative to symplectic capacities from rational symplectic field theory (SFT).
PubMed: 35994675
DOI: 10.1073/pnas.2203090119 -
Turk Kardiyoloji Dernegi Arsivi : Turk... Jun 2016Levoatriocardinal vein (LACV) is a rare cardiac pathology that represents a connection between the pulmonary venous and cardinal systems. The aim of the present study...
OBJECTIVE
Levoatriocardinal vein (LACV) is a rare cardiac pathology that represents a connection between the pulmonary venous and cardinal systems. The aim of the present study was to discuss morphological and clinical characteristics, as well as diagnostic methods, of experience with LACV.
METHODS
Records of 11 patients (4 male, 7 female; mean age 79±1.83 days; range 1-390 days) diagnosed with LACV between 2010 and 2014 were retrospectively reviewed. Presence of LACV was confirmed with echocardiography. The primary obstructive lesion associated with cardiac defects and the integrity of the interatrial septum was identified in each patient with left-sided obstruction.
RESULTS
Mean weight was 4.4±0.4 kg (range: 2-8). Age at presentation was under 1 year in 82% of patients. Nine patients had left-sided obstruction, and 2 had normal intracardiac anatomy and pulmonary venous return. In patients with left-sided obstruction, LACV was initially demonstrated with echocardiographic evaluation, performed in apical 4-chamber, high parasternal, and subcostal views. Atrial septum was restrictive or intact in patients with left-sided obstructions. LACV originated directly from the left atrium in all patients.
CONCLUSION
Levoatriocardinal vein is an extremely rare cardiac pathology, presenting almost exclusively in patients with left-sided obstructive lesions. In patients with left-sided obstructions, LACV must be kept in mind. It may also present in patients with normal intracardiac anatomy and pulmonary venous return.
Topics: Cardiovascular Abnormalities; Echocardiography; Female; Humans; Infant; Infant, Newborn; Male; Pulmonary Veins; Retrospective Studies; Tomography, X-Ray Computed
PubMed: 27372616
DOI: 10.5543/tkda.2015.84404 -
Chinese Medical Journal Sep 2021Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease characteristic of small airway inflammation, obstruction, and emphysema. It is well known that... (Review)
Review
Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease characteristic of small airway inflammation, obstruction, and emphysema. It is well known that spirometry alone cannot differentiate each separate component. Computed tomography (CT) is widely used to determine the extent of emphysema and small airway involvement in COPD. Compared with the pulmonary function test, small airway CT phenotypes can accurately reflect disease severity in patients with COPD, which is conducive to improving the prognosis of this disease. CT measurement of central airway morphology has been applied in clinical, epidemiologic, and genetic investigations as an inference of the presence and severity of small airway disease. This review will focus on presenting the current knowledge and methodologies in chest CT that aid in identifying discrete COPD phenotypes.
Topics: Airway Obstruction; Humans; Phenotype; Pulmonary Disease, Chronic Obstructive; Pulmonary Emphysema; Tomography, X-Ray Computed
PubMed: 34517376
DOI: 10.1097/CM9.0000000000001724 -
Revista de Investigacion Clinica;... 2019Non-obstructed ever-smokers, with or without symptoms, have generated a great deal of information recently, but few reviews. Even individuals with normal spirometry can... (Review)
Review
Non-obstructed ever-smokers, with or without symptoms, have generated a great deal of information recently, but few reviews. Even individuals with normal spirometry can present changes in sputum with inflammatory biomarkers (cellular and molecular) and airways and parenchyma with remodeling; when symptomatic (cough, sputum, wheezing, and dyspnea) exacerbations are frequent affecting the individuals' quality of life, there is an increased use of health resources: more medication, emergency visits, and hospital admissions. Non-obstructed smokers may have exercise limitations, increased lung volumes, low diffusion capacity, air entrapment, peripheral airways obstruction, elevated airways resistance, and abnormal multiple breath nitrogen washout, as well as abnormalities in computed tomography studies, such as airway wall thickening, emphysema, or interstitial lung abnormalities. Quitting smoking comprises a first, inexpensive, and often abandoned intervention to arrest respiratory impairment. It is controversial whether or not this population should be treated with other medications. Further studies should be conducted to elucidate the consequences of follow-up and prognosis in this clinical entity.
Topics: Humans; Prognosis; Quality of Life; Respiratory Tract Diseases; Smokers; Smoking; Smoking Cessation; Spirometry
PubMed: 30810539
DOI: 10.24875/RIC.18002648 -
Sleep Medicine Dec 2021Identification of the obstruction site in the upper airway may help in treatment selection for patients with sleep-disordered breathing. Because of limitations of... (Review)
Review
BACKGROUND
Identification of the obstruction site in the upper airway may help in treatment selection for patients with sleep-disordered breathing. Because of limitations of existing techniques, there is a continuous search for more feasible methods. Snoring sound parameters were hypothesized to be potential predictors of the obstruction site. Therefore, this review aims to i) investigate the association between snoring sound parameters and the obstruction sites; and ii) analyze the methodology of reported prediction models of the obstruction sites.
METHODS
The literature search was conducted in PubMed, Embase.com, CENTRAL, Web of Science, and Scopus in collaboration with a medical librarian. Studies were eligible if they investigated the associations between snoring sound parameters and the obstruction sites, and/or reported prediction models of the obstruction sites based on snoring sound.
RESULTS
Of the 1016 retrieved references, 28 eligible studies were included. It was found that the characteristic frequency components generated from lower-level obstructions of the upper airway were higher than those generated from upper-level obstructions. Prediction models were built mainly based on snoring sound parameters in frequency domain. The reported accuracies ranged from 60.4% to 92.2%.
CONCLUSIONS
Available evidence points toward associations between the snoring sound parameters in the frequency domain and the obstruction sites in the upper airway. It is promising to build a prediction model of the obstruction sites based on snoring sound parameters and participant characteristics, but so far snoring sound analysis does not seem to be a viable diagnostic modality for treatment selection.
Topics: Airway Obstruction; Humans; Nose; Sleep Apnea Syndromes; Sleep Apnea, Obstructive; Snoring; Sound
PubMed: 34749271
DOI: 10.1016/j.sleep.2021.10.015 -
ASAIO Journal (American Society For... 2017The hypothesis that blood flow monitoring could serve as an effective early indicator of distal obstruction during extracorporeal membrane oxygenation (ECMO) was tested...
The hypothesis that blood flow monitoring could serve as an effective early indicator of distal obstruction during extracorporeal membrane oxygenation (ECMO) was tested under controlled experimental conditions. The ECMO circuit typically includes (or could be easily modified to include) a shunt that bifurcates from the main line returning a small amount of blood to the pump with access points for drug infusions. Distal circuit obstructions in the oxygenator and beyond will result in an increased diversion of flow from the distal line to the shunt. Thus, elevations in flow through the shunt can serve as a marker for distal circuit obstruction. An ECMO training circuit was adapted with a resistance chamber that simulates controlled and varying levels of distal obstructions. Experiments were conducted under pediatric and adult pump target flow rates simulating different levels of distal obstructions while documenting the shunt flow and pressure drop across the obstruction. There was measurable and statistically significant elevation in the shunt flow at all flow rates because of different levels of obstruction from baseline values and hence consistent with the hypothesis that shunt flow can serve as an indicator of distal obstruction in the ECMO circuit. Flow monitoring is over the tube, hands free, continuous, and easy to implement. Therefore, it has the potential to serve as an early nonspecific indicator of elevated distal resistance in the ECMO circuit, which can then trigger other measurements (such as pressure drop across the oxygenator) for a more specific assessment of the source for distal resistance.
Topics: Adult; Blood Circulation; Extracorporeal Membrane Oxygenation; Humans; Infant; Pressure
PubMed: 28169848
DOI: 10.1097/MAT.0000000000000538 -
Respiratory Care Sep 2016Obstructive fibrinous tracheal pseudomembrane (OFTP) is an uncommon complication that results after tracheal intubation. Herein, we perform a systematic review of the... (Review)
Review
Obstructive fibrinous tracheal pseudomembrane (OFTP) is an uncommon complication that results after tracheal intubation. Herein, we perform a systematic review of the PubMed and EmBase databases for all the cases describing OFTP. The systematic search yielded 28 citations describing 53 subjects with OFTP. The study population (61.1% females) comprised of both adults and pediatric subjects with a median (IQR) age of 40.5 (14.8-60.5) years. The median (IQR) size of endotracheal tube was 7.5 (6-9.3) mm with a median (IQR) duration of intubation of 36 (14-96) hours. The median (IQR) time to onset of symptoms after extubation was 24 (6-96) hours. Stridor was the most common symptom. The average delay in correctly identifying the OFTP was 26 hours. The diagnosis of tracheal pseudomembrane was confirmed by flexible bronchoscopy in 38 (70.4%) instances while rigid bronchoscopy was used in 46.3% subjects for removing the pseudomembrane. There were two deaths, one each in an adult and a pediatric subject. OFTP is a complication of tracheal intubation and presents with respiratory failure. The diagnosis can be confirmed by flexible bronchoscopy. Treatment involves removal of the obstructing membrane with either flexible or rigid bronchoscopy.
Topics: Airway Extubation; Airway Obstruction; Bronchoscopy; Humans; Intubation, Intratracheal; Respiratory Sounds; Tracheal Diseases
PubMed: 27247431
DOI: 10.4187/respcare.04662 -
International Journal of Chronic... 2023Chronic obstructive pulmonary disease (COPD) is a disease defined by airflow obstruction with a high morbidity and mortality and significant economic burden. Although... (Review)
Review
Chronic obstructive pulmonary disease (COPD) is a disease defined by airflow obstruction with a high morbidity and mortality and significant economic burden. Although pulmonary function testing is the cornerstone in diagnosis of COPD, it cannot fully characterize disease severity or cause of dyspnea because of disease heterogeneity and variable related and comorbid conditions affecting cardiac, vascular, and musculoskeletal systems. Cardiopulmonary exercise testing (CPET) is a valuable tool for assessing physical function in a wide range of clinical conditions, including COPD. Familiarity with measurements made during CPET and its potential to aid in clinical decision-making related to COPD can thus be useful to clinicians caring for this population. This review highlights pulmonary and extrapulmonary impairments that can contribute to exercise limitation in COPD. Key elements of CPET are identified with an emphasis on measurements most relevant to COPD. Finally, clinical applications of CPET demonstrated to be of value in the COPD setting are identified. These include quantifying functional capacity, differentiating among potential causes of symptoms and limitation, prognostication and risk assessment for operative procedures, and guiding exercise prescription.
Topics: Humans; Pulmonary Disease, Chronic Obstructive; Exercise Test; Lung; Respiratory Function Tests; Dyspnea; Exercise Tolerance
PubMed: 38089541
DOI: 10.2147/COPD.S432841 -
BMC Surgery Jul 2019The laparoscopic Roux-en-Y gastric bypass (LRYGBP) is the second most performed bariatric surgical procedure. With the increasing number of patients undergoing bariatric...
BACKGROUND
The laparoscopic Roux-en-Y gastric bypass (LRYGBP) is the second most performed bariatric surgical procedure. With the increasing number of patients undergoing bariatric surgery, the number of complications is also growing. Early diagnosis and treatment of the complications is crucial.
CASE PRESENTATION
A very unusual complication was met after an uneventful laparoscopic gastric bypass (LGBP) procedure due to an obstructing blood clot in the biliairy limb resulting in an acute pancreatitis and gastric distention, accompanied by an obstructing blood clot in the distal ileum causing small bowel obstruction. A review of the occurrence of these complications and the diagnosis and treatment is presented.
CONCLUSION
Post-bariatric acute pancreatitis is uncommon, but could be fatal. Blood clots should be considered as possible causes of small bowel obstruction, ileus or pancreatitis.
Topics: Adult; Female; Gastric Bypass; Humans; Ileal Diseases; Intestinal Obstruction; Laparoscopy; Obesity, Morbid; Pancreatitis; Postoperative Complications; Tomography, X-Ray Computed
PubMed: 31277624
DOI: 10.1186/s12893-019-0532-6 -
PloS One 2019Congenital obstructive nephropathy is the main cause of end-stage renal disease in infants and children. Renal insufficiency is due to impaired growth and maturation in...
BACKGROUND
Congenital obstructive nephropathy is the main cause of end-stage renal disease in infants and children. Renal insufficiency is due to impaired growth and maturation in the developing kidney with obstruction. Congenital obstructive nephropathy leads to cytokine mediated inflammation and the development of interstitial fibrosis. The Janus kinase-2 (JAK-2) and Signal Transducer and Activator of Transcription'-3 (STAT3) are involved in cytokine production, inflammation, and interstitial fibrosis.
METHODS
We studied the role of JAK2/STAT3 in a model of congenital obstructive nephropathy using unilateral ureteral obstruction (UUO) in neonatal mice at the second day of life. Cytokine production, inflammation, and interstitial fibrosis were analyzed in obstructed and sham operated kidneys of neonatal mice treated with or without JAK2/STAT3 inhibitor Tyrphostin AG490. To mimic obstruction and distension, proximal tubular cells were stretched in vitro.
RESULTS
We show that STAT3 is highly activated in the developing kidney with obstruction and in proximal tubular cells following stretch. JAK2/STAT3 activation mediates cytokine release and leukocyte recruitment into neonatal kidneys after UUO. Pharmacological blockade of JAK2/STAT3 by Tyrphostin AG490 reduced inflammation, tubular apoptosis, and interstitial fibrosis. JAK2/STAT3 blockade decreased pro-inflammatory and profibrotic mediators in tubular cells.
CONCLUSION
Our findings provide evidence that JAK2/STAT3 mediates inflammation and fibrosis in the developing kidney with obstruction. Blocking JAK2/STAT3 may prove beneficial in congenital obstructive nephropathy in children.
Topics: Animals; Animals, Newborn; Enzyme Inhibitors; Fibrosis; Inflammation; Janus Kinase 2; Mice; STAT3 Transcription Factor; Tyrphostins; Ureteral Obstruction
PubMed: 31846485
DOI: 10.1371/journal.pone.0226675