Rat lungs show a biphasic formation of new alveoli during postnatal development

2014 ◽  
Vol 117 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Stefan A. Tschanz ◽  
Lilian A. Salm ◽  
Matthias Roth-Kleiner ◽  
Sebastien F. Barré ◽  
Peter H. Burri ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Morphological Description ◽  
Published Data ◽  
Second Phase ◽  
Weighted Mean ◽  
Biphasic Pattern ◽  
Rat Lungs ◽  
Alveolar Septa ◽  
Exchange Surface ◽  
Microvascular Maturation

Roughly 90% of the gas-exchange surface is formed by alveolarization of the lungs. To the best of our knowledge, the formation of new alveoli has been followed in rats only by means of morphological description or interpretation of semiquantitative data until now. Therefore, we estimated the number of alveoli in rat lungs between postnatal days 4 and 60 by unambiguously counting the alveolar openings. We observed a bulk formation of new alveoli between days 4 and 21 (17.4 times increase from 0.8 to 14.3 millions) and a second phase of continued alveolarization between days 21 and 60 (1.3 times increase to 19.3 million). The (number weighted) mean volume of the alveoli decreases during the phase of bulk alveolarization from ∼593,000 μm3 at day 4 to ∼141,000 μm3 at day 21, but increases again to ∼298,000 μm3 at day 60. We conclude that the “bulk alveolarization” correlates with the mechanism of classical alveolarization (alveolarization before the microvascular maturation is completed) and that the “continued alveolarization” follows three proposed mechanisms of late alveolarization (alveolarization after microvascular maturation). The biphasic pattern is more evident for the increase in alveolar number than for the formation of new alveolar septa (estimated as the length of the free septal edge). Furthermore, a striking negative correlation between the estimated alveolar size and published data on retention of nanoparticles was detected.

scholarly journals Lyophilized Fecal Microbiota Transplantation Capsules for Recurrent Clostridium difficile Infection

2017 ◽  
Vol 4 (suppl_1) ◽  
pp. S381-S381
Author(s):  
Hebert Dupont ◽  
Zhi-Dong Jiang ◽  
Ashley Alexander ◽  
Nadim Ajami ◽  
Joseph F Petrosino ◽  
...  
Keyword(s):  
Oral Delivery ◽  
Fecal Microbiota Transplantation ◽  
Fecal Microbiota ◽  
Gene Profiling ◽  
Intestinal Microbiome ◽  
Published Data ◽  
Rrna Gene ◽  
Second Phase ◽  
Microbiome Diversity

Abstract Background Fecal microbiota (FM) transplantation (FMT) is a highly effective treatment of recurrent C. difficile infection (rCDI). We have published data showing efficacy of fresh, frozen and lyophilized donor microbiota administered by colonoscopy. Most groups are moving toward use of frozen product given by enema and in evaluating encapsulated product for oral delivery. Methods This was a prospective, randomized study of subjects with rCDI (≥ 3 episodes) treated with encapsulated lyophilized FM 100 g given once or 100 g given on two successive days (total 200 g) vs. frozen FM product 100 g given by single retention enema, between March 2015 and February 2017. The clinical outcome was absence of CDI during the 60 days after FMT. The subjects were followed for 6 months for safety. In a subset recipients, microbiome composition by 16S rRNA gene profiling were analyzed on stools obtained pre- and day 2, 7, 14, 30, 60 and 90 days after FMT. Results A total of 54 subjects were enrolled (37/54; 69% female) with a median age of 71 years (range: 20–97). In the first 14 subjects treated, cure rates for oral capsules 100 g FM was 5/8 (63%) vs. 6/6 (100%) for those receiving 100 g frozen FM by enema (P = 0.209). In the second phase of the study cure rate for oral capsules 200 g FM was 17/18 (91%) vs. 20/21 (94%) for the subjects treated by enema by 100 g of frozen product (P = 0.782). No side effects were felt to be related to the procedure or the FMT products were recorded during 6 months follow-up. Two subjects died during follow-up between 3 and 6 months after study due to underlying medical conditions felt to be unrelated to FMT. Microbiota analysis were performed on 40 subjects of which 19/40 (48%) had received capsules. Figure showed that restoration of the intestinal microbiome diversity and Taxa began apparent by 2 days after FMT in both groups and resembled the donor product by 2 weeks with stabilization of the microbiota diversity and Taxa persisting for the 90 days of observation. Conclusion Administration of encapsulated, lyophilized FM resulted in durable restoration of intestinal microbiome diversity comparable to results seen with frozen product given by enema. Disclosures All authors: No reported disclosures.

Intrapulmonary blood flow redistribution during hypoxia increases gas exchange surface area

1982 ◽  
Vol 52 (6) ◽  
pp. 1575-1580 ◽  
Author(s):  
R. L. Capen ◽  
W. W. Wagner
Keyword(s):  
Carbon Monoxide ◽  
Blood Flow ◽  
Cardiac Output ◽  
Gas Exchange ◽  
Surface Area ◽  
Vascular Resistance ◽  
Diffusing Capacity ◽  
Capillary Recruitment ◽  
Blood Flow Redistribution ◽  
Exchange Surface

We have previously shown that airway hypoxia causes pulmonary capillary recruitment and raises diffusing capacity for carbon monoxide. This study was designed to determine whether these events were caused by an increase in pulmonary vascular resistance, which redistributed blood flow toward the top of the lung, or by an increase in cardiac output. We measured capillary recruitment at the top of the dog lung by in vivo microscopy, gas exchange surface area of the whole lung by diffusing capacity for carbon monoxide, and blood flow distribution by radioactive microspheres. During airway hypoxia recruitment occurred, diffusing capacity increased, and blood flow was redistributed upward. When a vasodilator was infused while holding hypoxia constant, these effects were reversed; i. e., capillary “derecruitment” occurred, diffusing capacity decreased, and blood flow was redistributed back toward the bottom of the lung. The vasodilator was infused at a rate that left hypoxic cardiac output unchanged. These data show that widespread capillary recruitment during hypoxia is caused by increased vascular resistance and the resulting upward blood flow redistribution.

New Insight into the Development of the Respiratory Acini in Rabbits: Morphological, Electron Microscopic Studies, and TUNEL Assay

2019 ◽  
Vol 25 (3) ◽  
pp. 769-785 ◽  
Author(s):  
Doaa M. Mokhtar ◽  
Manal T. Hussein ◽  
Marwa M. Hussein ◽  
Enas A. Abd-Elhafez ◽  
Gamal Kamel
Keyword(s):  
Tunel Assay ◽  
Second Phase ◽  
Type I ◽  
Apoptotic Cells ◽  
Clara Cells ◽  
Ciliated Cells ◽  
Blood Capillaries ◽  
Pulmonary Alveoli ◽  
Alveolar Septa ◽  
Terminal Bronchiole

AbstractThis study investigated the histomorphological features of developing rabbit respiratory acini during the postnatal period. On the 1st day of postnatal life, the epithelium of terminal bronchiole consisted of clear cells which intercalated between few ciliated and abundant non-ciliated (Clara) cells. At this age, the rabbit lung was in the alveolar stage. The terminal bronchioles branched into several alveolar ducts, which opened into atria that communicated to alveolar sacs. All primary and secondary inter-alveolar septa were thick and showed a double-capillary network (immature septa). The primitive alveoli were lined largely by type-I pneumocytes and mature type-II pneumocytes. The type-I pneumocytes displayed an intimate contact with the endothelial cells of the blood capillaries forming the blood–air barrier (0.90 ± 0.03 µm in thickness). On the 3rd day, we observed intense septation and massive formation of new secondary septa giving the alveolar sac a crenate appearance. The mean thickness of the air–blood barrier decreased to reach 0.78 ± 0.14 µm. On the 7th day, the terminal bronchiole epithelium consisted of ciliated and non-ciliated cells. The non-ciliated cells could be identified as Clara cells and serous cells. New secondary septa were formed, meanwhile the inter-alveolar septa become much thinner and the air–blood barrier thickness was 0.66 ± 0.03 µm. On the 14th day, the terminal bronchiole expanded markedly and the pulmonary alveoli were thin-walled. Inter-alveolar septa become much thinner and single capillary layers were observed. In the 1st month, the secondary septa increased in length forming mature cup-shaped alveoli. In the 2nd month, the lung tissue grew massively to involve the terminal respiratory unit. In the 3rd month, the pulmonary parenchyma appeared morphologically mature. All inter-alveolar septa showed a single-capillary layer, and primordia of new septa were also observed. The thickness of the air–blood barrier was much thinner; 0.56 ± 0.16 µm. TUNEL assay after birth revealed that the apoptotic cells were abundant and distributed in the epithelium lining of the pulmonary alveoli and the interstitium of the thick interalveolar septa. On the 7th day, and onward, the incidence of apoptotic cells decreased markedly. This study concluded that the lung development included two phases: the first phase (from birth to the 14th days) corresponds to the period of bulk alveolarization and microvascular maturation. The second phase (from the 14th days to the full maturity) corresponds to the lung growth and late alveolarization.

scholarly journals Exercise Testing of Adolescents and Young Adults With Sickle Cell Disease: Perceptual Responses and the Gas Exchange Threshold

2019 ◽  
Vol 36 (5) ◽  
pp. 310-320
Author(s):  
Suzanne Ameringer ◽  
R. K. Elswick ◽  
India Sisler ◽  
Wally Smith ◽  
Thokozeni Lipato ◽  
...  
Keyword(s):  
Young Adults ◽  
Sickle Cell Disease ◽  
Gas Exchange ◽  
Sickle Cell ◽  
Self Regulation ◽  
Adolescents And Young Adults ◽  
Published Data ◽  
Cell Disease ◽  
Perceived Effort ◽  
Gas Exchange Threshold

For individuals with sickle cell disease (SCD), mild to moderate exercise is advised, but self-regulation of these intensities is difficult. To regulate intensity, one SCD recommendation is to stop exercising at the first perception of fatigue. However, perceived effort and affect (how one feels) are perceptual cues that are commonly used to guide exercise intensity. This study (a) examined perceived effort, affect, and fatigue in relation to metabolic state (gas exchange) in adolescents and young adults (AYAs) with SCD, (b) explored guidelines AYAs use to self-regulate exercise, and (c) compared perceived effort and affect at gas exchange threshold (GET) with healthy counterparts. Twenty-two AYAs with SCD completed an incremental cycle test. Perceived effort, affect, and fatigue were assessed every 2 minutes. A mixed-effects linear model was conducted to model changes in effort, affect, and fatigue across time. Mean scores of effort and affect at GET were compared with published data of healthy counterparts. Participants were queried about self-regulation exercise strategies. Findings indicated that both perceived fatigue and effort at GET was lower than expected. Perceived effort was lower ( p < .0001), and perceived affect was significantly higher ( p = .0009) than healthy counterparts. Interviews revealed that most participants (95%) do not stop exercising until fatigue is moderate to severe, and many (73%) do not stop until symptoms are severe (chest tightness, blurry vision). Nurses should review guidelines for safe exercise with AYAs with SCD. Exercise training may be beneficial to AYAs with SCD for learning how to interpret bodily responses to exercise to improve self-regulation.

scholarly journals Stereological monitoring of mouse lung alveolarization from the early postnatal period to adulthood

2017 ◽  
Vol 312 (6) ◽  
pp. L882-L895 ◽  
Author(s):  
Agnieszka Pozarska ◽  
José Alberto Rodríguez-Castillo ◽  
David E. Surate Solaligue ◽  
Aglaia Ntokou ◽  
Philipp Rath ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Surface Area ◽  
Lung Development ◽  
Laboratory Mouse ◽  
Mouse Lung ◽  
Postnatal Life ◽  
Lung Maturation ◽  
Septal Wall ◽  
Mouse Lungs ◽  
Exchange Surface

Postnatal lung maturation generates a large number of small alveoli, with concomitant thinning of alveolar septal walls, generating a large gas exchange surface area but minimizing the distance traversed by the gases. This demand for a large and thin gas exchange surface area is not met in disorders of lung development, such as bronchopulmonary dysplasia (BPD) histopathologically characterized by fewer, larger alveoli and thickened alveolar septal walls. Diseases such as BPD are often modeled in the laboratory mouse to better understand disease pathogenesis or to develop new interventional approaches. To date, there have been no stereology-based longitudinal studies on postnatal mouse lung development that report dynamic changes in alveoli number or alveolar septal wall thickness during lung maturation. To this end, changes in lung structure were quantified over the first 22 mo of postnatal life of C57BL/6J mice. Alveolar density peaked at postnatal day (P)39 and remained unchanged at 9 mo (P274) but was reduced by 22 mo (P669). Alveoli continued to be generated, initially at an accelerated rate between P5 and P14, and at a slower rate thereafter. Between P274 and P669, loss of alveoli was noted, without any reduction in lung volume. A progressive thinning of the alveolar septal wall was noted between P5 and P28. Pronounced sex differences were observed in alveoli number in adult (but not juvenile) mice, when comparing male and female mouse lungs. This sex difference was attributed exclusively to the larger volume of male mouse lungs.

Multiple-breath washout experiments in rat lungs

1991 ◽  
Vol 71 (3) ◽  
pp. 847-854 ◽  
Author(s):  
S. Verbanck ◽  
N. Gonzalez Mangado ◽  
G. Peces-Barba ◽  
M. Paiva
Keyword(s):  
Gas Exchange ◽  
Wistar Rats ◽  
Breath Hold ◽  
Ventilation Distribution ◽  
Lung Volumes ◽  
Rat Lungs ◽  
Horizontal Asymptote ◽  
Multiple Breath Washout ◽  
Diffusion And Convection

Multiple-breath washouts were performed on 30 Wistar rats postmortem in a study in which breaths of 90% O2–5% He-5% SF6 were given. Preliminary comparison of alveolar plateau slopes obtained from anesthetized rats in vivo and postmortem showed that ventilation distribution remains the same within 1 h after the animals were killed. For maneuvers with different preinspiratory lung volumes and end-inspiratory breathholding, we computed the normalized N2 slope (Sn) and Fowler and Bohr dead spaces [VDF(n) and VDB(n), respectively] as a function of breath number (n). For all maneuvers analyzed, Sn of all gases increased in the first two or three breaths and reached a horizontal asymptote thereafter. The value of Sn decreased, both with increasing preinspiratory lung volume and breath hold of 4 s. The fact that the horizontal Sn asymptote is reached after only two or three breaths suggests the absence of convection-dependent inhomogeneities (CDI) in rat lungs. This contrasts with multiple-breath washout experiments in humans, where interregional (gravity-dependent CDI) and intraregional CDI generate a marked increase in Sn throughout the entire washout. Also, in contrast with results in humans, VDF and VDB were independent of n. The present work suggests that rats may be used to study diffusion- and convection-dependent inhomogeneities without the influence of CDI or gas exchange.

scholarly journals Taxonomy and distribution of enigmatic “helicoid” Polygyratia Gray, 1847 (Gastropoda, Stylommatophora)

2020 ◽  
Vol 96 (1) ◽  
pp. 91-101
Author(s):  
Rodrigo Brincalepe Salvador ◽  
Daniel Caracanhas Cavallari
Keyword(s):  
Geographical Distribution ◽  
Atlantic Forest ◽  
Taxonomic Revision ◽  
Morphological Description ◽  
Published Data ◽  
Museum Specimens ◽  
Online Database ◽  
First Report ◽  
Occurrence Data ◽  
Eastern Brazil

Herein, we present a taxonomic revision of the genus Polygyratia Gray, 1847, with a new systematic placement in Scolodontidae and containing only the species Polygyratia polygyrata (Born, 1778). We offer an updated morphological description and geographical distribution, based on museum specimens and occurrence data gathered from literature and online database iNaturalist. We synonymise P. charybdis Mörch, 1852 with P. polygyrata. The species is known only from Atlantic Forest areas in Bahia state, eastern Brazil. We exclude three other species from the genus Polygyratia, classifying them as: Systrophia (Systrophia) heligmoida (d’Orbigny, 1835) and S. (Entodina) reyrei (Souverbie, 1858), based on conchological features; and S. (E.) pollodonta (d’Orbigny, 1835), though tentatively, based on scant published data. Finally, we present the first report of S. (S.) heligmoida (d’Orbigny, 1835) from Brazil.

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