Structural and functional evidence for the scaffolding effect of alveolar blood vessels.

A contribution of pulmonary blood distension to alveolar opening was first proposed more than 100 years ago. To investigate the contribution of blood distension to lung mechanics, we studied control mice (normal perfusion), mice after exsanguination (absent perfusion) and mice after varying degrees of parenchymal resection (supra-normal perfusion). On inflation, mean tracheal pressures were higher in the bloodless mouse (4.0 ± 2.5 cm H2O); however, there was minimal difference between conditions on deflation (0.7 ± 0.9 cm H2O). To separate the peripheral and central mechanical effects of blood volume, multi-frequency lung impedance data was fitted to the constant-phase model. The presence or absence of blood had no effect on central airway resistance (p > .05). In contrast, measures of tissue damping (G), tissue elastance (H) and hysteresivity (η) demonstrated a significant increase in bloodless mice relative to control mice (p < .001). After varying amount of surgical resection and associated supra-normal perfusion of the remaining lung, there was an increase in G and H. Although the absolute difference in G and H increased with the amount of parenchymal resection, the proportional contribution of blood was identical in all conditions. The presence of blood in the pulmonary vasculature resulted in a constant 64 ± 5% reduction in tissue damping (G) and a 55 ± 4% reduction in tissue elastance (H). This nearly-constant contribution of blood to lung hysteresivity was only reduced by positive end-expiratory pressure (PEEP). To identify a distinct structural subset of vessels in the lung potentially contributing to these observations, vascular casting and scanning electron microscopy of the lung demonstrated morphologically distinct vascular rings at the alveolar opening. Our results suggest that intravascular blood distension, likely attributable to a subset of vessels in the alveolar entrance ring, contributes a measurable scaffolding effect to the functional recruitment of the peripheral lung.

Innovative bridging of the rural-urban divide: comparison of scope, safety, and impact of collaborative rural surgery camps and an urban surgical program.

BACKGROUND: In medically under-resourced regions worldwide, non-permanent surgery programs or camps have been conducted to expand access to surgical services. Surgery camp programs have been reported in rural India, primarily in the ophthalmic and obstetric fields; however, the provision of general surgical services in these settings is largely unknown. METHODS: A 12-month retrospective review of non-ambulatory procedures performed at a rural hospital surgery camp program and at an urban hospital in Maharashtra, India, was completed to characterize relative differences in procedural activity, frequency and severity of perioperative complications, and to evaluate efficacy of care. RESULTS: A total of 449 cases performed in rural hospital surgery camps were compared with 344 cases performed in an urban hospital during the course of the study period. The majority of rural surgical cases were elective and of intermediate complexity. Approximately 4% of rural cases were complex-major compared to 17% of urban cases. Intraoperative complications occurred in 0.2% rural cases compared to 5.5% of urban cases; p = 0.01. Postoperative complications were predominantly low grade in both groups. The postoperative complication rate was higher among rural surgical patients (43.4%; 23.5%; p < 0.01), though the Surgical Risk Score was significantly lower in this group (p < 0. 01). Rural surgery camp activity over 12 months achieved diagnostic and/or therapeutic goals in 92.2% of procedures and rendered 1.74-2.69 disability-adjusted life-years (DALYs) averted per patient. CONCLUSIONS: Rural general surgery camps can safely and effectively provide a wide range of surgical services under appropriate collaborative and clinical conditions. Surgery camps may be a safe, temporizing solution to unmet needs until substantial gains in rural healthcare are realized.

Effect of unilateral diaphragmatic paralysis on postpneumonectomy lung growth.

Respiratory muscle-associated stretch has been implicated in normal lung development (fetal breathing movements) and postpneumonectomy lung growth. To test the hypothesis that mechanical stretch from diaphragmatic contraction contributes to lung growth, we performed left phrenic nerve transections (PNT) in mice with and without ipsilateral pneumonectomy. PNT was demonstrated by asymmetric costal margin excursion and confirmed at autopsy. In mice with two lungs, PNT was associated with a decrease in ipsilateral lung volume (P<0.05) and lung weight (P<0.05). After pneumonectomy, PNT was not associated with a change in activity level, measureable hypoxemia, or altered minute ventilation; however, microCT scanning demonstrated altered displacement and underinflation of the cardiac lobe within the first week after pneumonectomy. Coincident with the altered structural realignment, lung impedance measurements, fitted to the constant-phase model, demonstrated elevated airway resistance (P<0.05), but normal peripheral tissue resistance (P>0.05). Most important, PNT appeared to abrogate compensatory lung growth after pneumonectomy; the weight of the lobes of the right lung was significantly less than pneumonectomy alone (P<0.001) and indistinguishable from nonsurgical controls (P>0.05). We conclude that the cyclic stretch associated with diaphragmatic muscle contraction is a controlling factor in postpneumonectomy compensatory lung growth.

Financial burden of thyroid cancer in the United States: An estimate of economic and psychological hardship among thyroid cancer survivors.

BACKGROUND: Annual cancer-related healthcare expenditure in the United States is estimated to exceed $150 billion by 2020. As the prevalence of thyroid cancer increases worldwide, thyroid cancer survivorship is associated with increasing personal and cumulative costs. Few studies have examined the psychological and material economic costs experienced by thyroid cancer survivors. We seek to estimate the comparative prevalence of financial and psychological hardship among thyroid cancer and non-thyroid cancer patients in the United States. METHODS: The 2011 Medical Expenditure Panel Survey Experiences with Cancer databank was queried to identify thyroid and non-thyroid (colon, breast, lung, prostate) cancer survivors. This survey includes assessments of financial stress, material hardship, and psychological financial hardship. Cancer incidence-based weighted estimates of responses were compared between thyroid and non-thyroid cancer survivors. Independent predictors of material and psychological financial burden were identified through separate multivariate regression models. RESULTS: Thyroid cancer survivors more frequently reported psychological financial burden compared to non-thyroid cancer (46.1% vs 24.0%, P = .04). Material financial hardship (28.1% vs 19.9%, P = .37) and concurrent material and psychological hardship (25.1% vs 12.5%, P = .09) were noted at similar frequencies between thyroid and non-thyroid cancer survivors. However, on multivariate analysis, only younger age and lack of health insurance coverage were independently associated with psychological financial hardship. CONCLUSION: Thyroid cancer survivors report greater psychological financial hardship than non-thyroid cancer survivors. Because this financial burden may be underrecognized in the medical community, further studies should be conducted to aid physicians in better understanding the impact of a thyroid cancer diagnosis.

Pediatric toxic polycystic thyroid.

BACKGROUND: Polycystic thyroid disease (PCTD) is a rare condition and has been described in adults in the setting of subclinical and clinical hypothyroidism. We present the first known case of a pediatric patient with diffuse macrocystic degeneration of the thyroid. CLINICAL PRESENTATION: A 6-year-old previously healthy patient was evaluated after presenting with a 16-month history of an enlarging polycystic thyroid and hyperthyroidism. Markers of autoimmune thyroid disease including thyroid stimulating immunoglobulin (TSI), thyroid stimulating hormone (TSH) receptor antibody, thyroid peroxidase antibody and thyroglobulin antibody were negative. No family history of benign or malignant thyroid or cystic disease was present. The patient underwent a total thyroidectomy without perioperative complication. She remains euthyroid with thyroid hormone replacement therapy. SUMMARY: To our knowledge, this is the first report of PCTD in the pediatric population associated with hyperthyroidism without evidence of autoimmune disease. Somatic activating thyrotropin-receptor gene mutations are known to cause non-autoimmune hyperthyroidism in children, however it is unknown if similar mechanisms are responsible for pediatric PCTD. CONCLUSIONS: Polycystic thyroid degeneration can occur in children and may result in a hyperthyroid state.

Extracellular Assembly of the Elastin Cable Line Element in the Developing Lung.

In the normal lung, a dominant structural element is an elastic "line element" that originates in the central bronchi and inserts into the distal airspaces. Despite its structural importance, the process that leads to development of the cable line element is unknown. To investigate the morphologic events contributing to its development, we used optical clearing methods to examine the postnatal rat lung. An unexpected finding was numerous spheres, with a median diameter of 1-2 µm, within the primary septa of the rat lung. The spheres demonstrated green autofluorescence, selective fluorescent eosin staining, reactivity with carboxyfluorescein succinimidyl ester, and specific labeling with anti-tropoelastin monoclonal antibody-findings consistent with tropoelastin. The sphere number peaked on rat postnatal day 4 (P4) and were rare by P14. The disappearance of the spheres was coincident with the development of the cable line element in the rat lung. Transmission electron microscopy demonstrated no consistent association between parenchymal cells and sphere alignment. In contrast, the alignment of tropoelastin spheres appeared to be the direct result of interactions of scaffold proteins including collagen fibers and fibrillin microfibrils. We conclude that the spatial organization of the cable line element appears to be independent of tropoelastin deposition, but dependent on crosslinking to scaffold proteins within the primary septa. Anat Rec, 300:1670-1679, 2017. © 2017 Wiley Periodicals, Inc.

Laser microdissection of the alveolar duct enables single-cell genomic analysis.

Complex tissues such as the lung are composed of structural hierarchies such as alveoli, alveolar ducts, and lobules. Some structural units, such as the alveolar duct, appear to participate in tissue repair as well as the development of bronchioalveolar carcinoma. Here, we demonstrate an approach to conduct laser microdissection of the lung alveolar duct for single-cell PCR analysis. Our approach involved three steps. (1) The initial preparation used mechanical sectioning of the lung tissue with sufficient thickness to encompass the structure of interest. In the case of the alveolar duct, the precision-cut lung slices were 200 µm thick; the slices were processed using near-physiologic conditions to preserve the state of viable cells. (2) The lung slices were examined by transmission light microscopy to target the alveolar duct. The air-filled lung was sufficiently accessible by light microscopy that counterstains or fluorescent labels were unnecessary to identify the alveolar duct. (3) The enzymatic and microfluidic isolation of single cells allowed for the harvest of as few as several thousand cells for PCR analysis. Microfluidics based arrays were used to measure the expression of selected marker genes in individual cells to characterize different cell populations. Preliminary work suggests the unique value of this approach to understand the intra- and intercellular interactions within the regenerating alveolar duct.

Laparoscopic surgical treatment for refractory gastric antral vascular ectasia: a case report and review.

Gastric antral vascular ectasia (GAVE) is an angiodysplastic disorder of unclear etiology and rare cause of upper gastrointestinal bleeding. Endoscopic findings of hyperemic antral folds with dilated, tortuous vessels extending radially from the pylorus are diagnostic. Ectatic submucosal capillaries, microvascular fibrin thrombosis, and fibromuscular hyperplasia in the lamina propria are distinctive histologic features. Diverse treatment options are available, ranging from conservative medical or endoscopic therapy to surgical resection of affected gastric region. Surgery is the only known curative treatment and is traditionally pursued after failure of conservative therapy, as high postoperative mortality has been reported. A case of refractory GAVE in a 71-year-old female patient after 5 years of conservative management, is presented. The patient underwent successful laparoscopic distal gastrectomy and gastrojejunostomy with resolution of symptomatic anemia and melena. Clinical findings, diagnosis, etiology, and treatment of GAVE are reviewed here, with discussion of safety and efficacy of laparoscopic gastric resection for its treatment.