Some red blood cell geometry

1983 ◽  
Vol 61 (6) ◽  
pp. 646-649 ◽  
Author(s):  
H. Westcott Vayo
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Model Parameters ◽  
Sectional Area ◽  
Cell Geometry ◽  
Cross Sectional ◽  
Cell Dimensions ◽  
Rectangular Form ◽  
Computer Calculations ◽  
The Relationship

Formulas are presented for the cross-sectional area, volume, surface area, and circumference of a model red blood cell based on the Oval of Cassini as the geometry of choice. The relationship between the actual cell dimensions and model parameters is given as is the criterion for the validity of the model used in the formulary. Each formula is given in rectangular form and in a form suitable for computer calculations.

scholarly journals Red Blood Cell Transfusion in the Emergency Department: An Observational Cross-Sectional Multicenter Study

2021 ◽  
Vol 10 (11) ◽  
pp. 2475
Author(s):  
Olivier Peyrony ◽  
Danaé Gamelon ◽  
Romain Brune ◽  
Anthony Chauvin ◽  
Daniel Aiham Ghazali ◽  
...  
Keyword(s):  
Emergency Department ◽  
Logistic Regression ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Cross Sectional Study ◽  
Red Blood Cell Transfusion ◽  
Cross Sectional ◽  
Acute Bleeding ◽  
History Of ◽  
Rbc Transfusion

Background: We aimed to describe red blood cell (RBC) transfusions in the emergency department (ED) with a particular focus on the hemoglobin (Hb) level thresholds that are used in this setting. Methods: This was a cross-sectional study of 12 EDs including all adult patients that received RBC transfusion in January and February 2018. Descriptive statistics were reported. Logistic regression was performed to assess variables that were independently associated with a pre-transfusion Hb level ≥ 8 g/dL. Results: During the study period, 529 patients received RBC transfusion. The median age was 74 (59–85) years. The patients had a history of cancer or hematological disease in 185 (35.2%) cases. Acute bleeding was observed in the ED for 242 (44.7%) patients, among which 145 (59.9%) were gastrointestinal. Anemia was chronic in 191 (40.2%) cases, mostly due to vitamin or iron deficiency or to malignancy with transfusion support. Pre-transfusion Hb level was 6.9 (6.0–7.8) g/dL. The transfusion motive was not notified in the medical chart in 206 (38.9%) cases. In the multivariable logistic regression, variables that were associated with a higher pre-transfusion Hb level (≥8 g/dL) were a history of coronary artery disease (OR: 2.09; 95% CI: 1.29–3.41), the presence of acute bleeding (OR: 2.44; 95% CI: 1.53–3.94), and older age (OR: 1.02/year; 95% CI: 1.01–1.04). Conclusion: RBC transfusion in the ED was an everyday concern and involved patients with heterogeneous medical situations and severity. Pre-transfusion Hb level was rather restrictive. Almost half of transfusions were provided because of acute bleeding which was associated with a higher Hb threshold.

Identification of the biomechanical factors associated with the perception of distension in the human esophagus

2002 ◽  
Vol 282 (4) ◽  
pp. G683-G689 ◽  
Author(s):  
J. D. Barlow ◽  
H. Gregersen ◽  
D. G. Thompson
Keyword(s):  
Cross Sectional Area ◽  
Sectional Area ◽  
Limited Information ◽  
Butyl Bromide ◽  
Cross Sectional ◽  
Impedance Planimetry ◽  
Sensory Responses ◽  
Human Esophagus ◽  
Biomechanical Factors ◽  
The Relationship

Current techniques used to investigate the mechanisms responsible for the sensory responses to distension of the human esophagus provide limited information because the degree of circumferential stretch required to determine tension can only be inferred. We used impedance planimetry to measure the cross-sectional area during esophageal distension to ascertain the degree of stretch and tension that initiated motor and sensory responses. Hyoscine- N-butyl bromide (HBB), a cholinergic muscarinic receptor blocker, was also used to alter esophageal tension during distension. Motor activity was initiated at a lower degree of stretch and tension than that which initiated sensory awareness; both increased directly with increasing distension. HBB reduced both esophageal motility and tension during distension without altering the relationship between sensation intensity and cross-sectional area. Esophageal stretch, rather than tension, thus appears to be the major factor influencing sensory responses to esophageal distension.

scholarly journals Effect of red blood cell transfusion on short-term outcomes in very low birth weight infants

2020 ◽  
Vol 63 (2) ◽  
pp. 56-62
Author(s):  
Eui Young Lee ◽  
Sung Shin Kim ◽  
Ga Young Park ◽  
Sun Hyang Lee
Keyword(s):  
Birth Weight ◽  
Low Birth Weight ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Very Low Birth Weight ◽  
Short Term ◽  
Vlbw Infants ◽  
Early Onset Sepsis ◽  
The Relationship ◽  
Rbc Transfusion

Background: Red blood cell (RBC) transfusion improves cardiorespiratory status of preterm infants by increasing circulating hemoglobin, improving tissue oxygenation, and reducing cardiac output. However, RBC transfusion itself has also been suggested to negatively affect short-term outcomes such as intraventricular hemorrhage (IVH), bronchopulmonary dysplasia (BPD), retinopathy of prematurity (ROP), and necrotizing enterocolitis (NEC) in premature infants.Purpose: This study aimed to analyze the relationship between RBC transfusion and short-term outcomes in very low birth weight (VLBW) infants (birth weight, <1,500 g).Methods: We retrospectively reviewed the medical records of VLBW infants admitted to the Soonchunhyang University Bucheon Hospital between October 2010 and December 2017. Infants who died during hospitalization were excluded. The infants were divided into 2 groups according to RBC transfusion status. We investigated the relationship between RBC transfusion and short-term outcomes including BPD, ROP, NEC, and IVH.Results: Of the 250 enrolled VLBW infants, 109 (43.6%) underwent transfusion. Univariate analysis revealed that all shortterm outcomes except early-onset sepsis and patent ductus arteriosus were associated with RBC transfusion. In multivariate analysis adjusted for gestational age, birth weight and Apgar score at 1 minute, RBC transfusion was significantly correlated with BPD (odds ratio [OR], 5.42; <i>P</i><0.001) and NEC (OR, 3.40; <i>P</i>= 0.009).Conclusion: RBC transfusion is significantly associated with adverse clinical outcomes such as NEC and BPD in VLBW infants. Careful consideration of the patient’s clinical condition and appropriate guidelines is required before administration of RBC transfusions.

scholarly journals Per-pass analysis of acute ischemic stroke clots: impact of stroke etiology on extracted clot area and histological composition

2020 ◽  
pp. neurintsurg-2020-016966
Author(s):  
Seán Fitzgerald ◽  
Rosanna Rossi ◽  
Oana Madalina Mereuta ◽  
Duaa Jabrah ◽  
Adaobi Okolo ◽  
...  
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Formation Mechanisms ◽  
Large Artery ◽  
Cell Content ◽  
Stroke Etiology ◽  
Clot Burden ◽  
Similar Formation ◽  
The Relationship ◽  
Radiological Studies

BackgroundInitial studies investigating correlations between stroke etiology and clot composition are conflicting and do not account for clot size as determined by area. Radiological studies have shown that cardioembolic strokes are associated with shorter clot lengths and lower clot burden than non-cardioembolic clots.ObjectiveTo report the relationship between stroke etiology, extracted clot area, and histological composition at each procedural pass.MethodsAs part of the multi-institutional RESTORE Registry, the Martius Scarlett Blue stained histological composition and extracted clot area of 612 per-pass clots retrieved from 441 patients during mechanical thrombectomy procedures were quantified. Correlations with clinical and procedural details were investigated.ResultsClot composition varied significantly with procedural passes; clots retrieved in earlier passes had higher red blood cell content (H4=11.644, p=0.020) and larger extracted clot area (H4=10.730, p=0.030). Later passes were associated with significantly higher fibrin (H4=12.935, p=0.012) and platelets/other (H4=15.977, p=0.003) content and smaller extracted clot area. Large artery atherosclerotic (LAA) clots were significantly larger in the extracted clot area and more red blood cell-rich than other etiologies in passes 1–3. Cardioembolic and cryptogenic clots had similar histological composition and extracted clot area across all procedural passes.ConclusionLAA clots are larger and associated with a large red blood cell-rich extracted clot area, suggesting soft thrombus material. Cardioembolic clots are smaller in the extracted clot area, consistent in composition and area across passes, and have higher fibrin and platelets/other content than LAA clots, making them stiffer clots. The per-pass histological composition and extracted clot area of cryptogenic clots are similar to those of cardioembolic clots, suggesting similar formation mechanisms.

Changes in airway length after unilateral pneumonectomy in weanling ferrets

1990 ◽  
Vol 68 (1) ◽  
pp. 187-192 ◽  
Author(s):  
K. K. Kirchner ◽  
J. T. McBride
Keyword(s):  
Quadratic Equation ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Peripheral Airways ◽  
Peripheral Airway ◽  
The Relationship ◽  
Bronchial Casts ◽  
Central Airway ◽  
Terminal Bronchiole

We have previously shown that airway cross-sectional area increases 15-20% after pneumonectomy in weanling ferrets by measuring bronchial casts. We have now reanalyzed these same casts to quantitate changes in airway length after pneumonectomy. In each cast the distance from each of 120 airways to the terminal bronchiole along its axial pathway was measured. The relationship between the logarithm of this distance and that of the fraction of the lobe subtended by an airway could be described by a quadratic equation with a correlation coefficient greater than 0.85. Subsegmental and more distal airways of postpneumonectomy animals were 33-47% longer than those of controls. Overall the main axial pathway of airways in the left lower lobes was 12% longer in operated animals, but this increase was primarily accounted for by an increase in the length of the more peripheral airways. Central airways were little if any longer in operated animals. After pneumonectomy in weanling ferrets, subsegmental and peripheral airway lengths increase to a greater degree than lung volume and airway cross-sectional area, whereas central airway lengths increase to a lesser extent if at all. The mechanisms responsible for this difference between central and intralobar compensatory airway growth are unknown.

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