scholarly journals Polycythemia Vera: Age Relationships and Survival

Blood ◽  
1965 ◽  
Vol 26 (3) ◽  
pp. 243-256 ◽  
Author(s):  
EDWIN E. OSGOOD
Keyword(s):  
Normal Distribution ◽  
Polycythemia Vera ◽  
Age At Onset ◽  
Age Distribution ◽  
Previous Treatment ◽  
Age At Death ◽  
Survival Times ◽  
Relative Age ◽  
Highly Correlated ◽  
Log Normal

Abstract Study of our first 201 cases of polycythemia vera and of cases reported in the literature shows a remarkable age distribution for this disease. The age at onset, age at diagnosis, age at first treatment, and age at death, as well as survival times, each fits a normal distribution. In our cases, the median age at onset is 57 years with a standard deviation of 13 years, an entirely different distribution from that for the population of Oregon. This requires a logarithmic increase in relative age specific incidence from age 20 to 40, when there is little difference in the number of persons alive at each age, with a doubling of the proportion occurring in each 5-year interval every 7.5 years. After age 55, the proportion of new cases developing follows the slope of the number alive in the population. This means that the incidence remains almost constant after the peak age incidence is reached. Unfortunately, no data exist to transform these figures to absolute values, but if enough of the population could be studied to give absolute values at any one point, all other points could be determined. The implication is that polycythemia vera is due to a single cause which is highly correlated with age. The normal distribution of survival times means that polycythemia vera is not a malignant process since survival times in all malignancies studied fit a log normal distribution. The constant value of age at death means that age at first treatment is a most important prognostic factor. The mean age at death of patients with polycythemia vera, treated with P32, is 69 years ± 1, and treated without radiation therapy is 65 years ± 1. Apparently, if a patient lives to be treated with P32 previous treatment by other modalities or no treatment prior to that, will not affect the years to be gained by P32 treatment. However, the total survival time is highly correlated with age and the sooner after onset that the patient can be treated the more likely it is he will benefit from P32 therapy.

Variance of ventilation during exercise

2001 ◽  
Vol 90 (6) ◽  
pp. 2151-2156 ◽  
Author(s):  
Kenneth C. Beck ◽  
Theodore A. Wilson
Keyword(s):  
Standard Deviation ◽  
Normal Distribution ◽  
Ventilation Distribution ◽  
Cycle Exercise ◽  
Expired Gas ◽  
Highly Correlated ◽  
Log Normal ◽  
Male Subjects ◽  
Log Normal Distribution ◽  
Ventilation And Perfusion

Expired gas concentrations were measured during a multibreath washin of He in one female and seven male subjects at rest (seated) and during cycle exercise at work rates of 70–210 W. In a computational model, the ventilation distribution was represented as a log-normal distribution with standard deviation (ςV˙); values of ςV˙ were obtained by fitting the output of the model to the data. At rest, ςV˙ was 0.89 ± 0.18; during exercise, ςV˙ was 0.60 ± 0.13, independent of the level of exercise. These values for the width of the functional ventilation distribution at the scale of the acinus are approximately two times larger than those obtained from anatomic measurements in animals at a scale of 1 cm3. The values for ςV˙, together with data from the literature on the width of the functional ventilation-perfusion distribution, show that ventilation and perfusion are highly correlated at rest, in agreement with anatomic data. The structural sources of nonuniform ventilation and perfusion and of the correlation between them are unknown.

Deviation in the Age Structure of Mortality as an Indicator of COVID-19 Pandemic Severity

2022 ◽  
Vol 112 (1) ◽  
pp. 165-168
Author(s):  
Siddharth Chandra ◽  
Madhur Chandra
Keyword(s):  
Age Structure ◽  
Goodness Of Fit ◽  
Age Distribution ◽  
The United States ◽  
Age At Death ◽  
Fit Statistics ◽  
Kolmogorov Smirnov ◽  
Highly Correlated ◽  
Pandemic Severity ◽  
Death Data

Objectives. To test whether distortions in the age distribution of deaths can track pandemic activity. Methods. We compared weekly distributions of all-cause deaths by age during the COVID-19 pandemic in the United States from March to December 2020 with corresponding prepandemic weekly baseline distributions derived from data for 2015 to 2019. We measured distortions via Kolmogorov–Smirnov (K-S) and χ2 goodness-of-fit statistics as well as deaths among individuals aged 65 years or older as a percentage of total deaths (PERC65+). We computed bivariate correlations between these measures and the number of recorded COVID-19 deaths for the corresponding weeks. Results. Elevated COVID-19-associated fatalities were accompanied by greater distortions in the age structure of mortality. Distortions in the age distribution of weekly US COVID-19 deaths in 2020 relative to earlier years were highly correlated with COVID fatalities (K-S: r = 0.71, P < .001; χ2: r = 0.90, P < .001; PERC65+: r = 0.85, P < .001). Conclusions. A population-representative sample of age-at-death data can serve as a useful means of pandemic activity surveillance when precise cause-of-death data are incomplete, inaccurate, or unavailable, as is often the case in low-resource environments. (Am J Public Health. 2022;112(1):165–168. https://doi.org/10.2105/AJPH.2021.306567 )

scholarly journals Binary and analog variation of synapses between cortical pyramidal neurons

2019 ◽  
Author(s):  
Sven Dorkenwald ◽  
Nicholas L. Turner ◽  
Thomas Macrina ◽  
Kisuk Lee ◽  
Ran Lu ◽  
...  
Keyword(s):  
Normal Distribution ◽  
Cortical Neurons ◽  
Pyramidal Neurons ◽  
Network Models ◽  
Pyramidal Cells ◽  
Automated Analysis ◽  
Neural Network Models ◽  
Highly Correlated ◽  
Log Normal ◽  
Log Normal Distribution

AbstractLearning from experience depends at least in part on changes in neuronal connections. We present the largest map of connectivity to date between cortical neurons of a defined type (L2/3 pyramidal cells), which was enabled by automated analysis of serial section electron microscopy images with improved handling of image defects. We used the map to identify constraints on the learning algorithms employed by the cortex. Previous cortical studies modeled a continuum of synapse sizes (Arellano et al., 2007) by a log-normal distribution (Loewenstein, Kuras and Rumpel, 2011; de Vivo et al., 2017; Santuy et al., 2018). A continuum is consistent with most neural network models of learning, in which synaptic strength is a continuously graded analog variable. Here we show that synapse size, when restricted to synapses between L2/3 pyramidal cells, is well-modeled by the sum of a binary variable and an analog variable drawn from a log-normal distribution. Two synapses sharing the same presynaptic and postsynaptic cells are known to be correlated in size (Sorra and Harris, 1993; Koester and Johnston, 2005; Bartol et al., 2015; Kasthuri et al., 2015; Dvorkin and Ziv, 2016; Bloss et al., 2018; Motta et al., 2019). We show that the binary variables of the two synapses are highly correlated, while the analog variables are not. Binary variation could be the outcome of a Hebbian or other synaptic plasticity rule depending on activity signals that are relatively uniform across neuronal arbors, while analog variation may be dominated by other influences. We discuss the implications for the stability-plasticity dilemma.

Prediction of Haemoglobin Level by Some Probability Distribution

2020 ◽  
Vol 9 (1) ◽  
pp. 84-88
Author(s):  
Govinda Prasad Dhungana ◽  
Laxmi Prasad Sapkota
Keyword(s):  
Probability Distribution ◽  
Normal Distribution ◽  
Goodness Of Fit ◽  
Continuous Variable ◽  
Hemoglobin Level ◽  
Chi Square ◽  
Chi Square Test ◽  
Log Normal ◽  
Two Parameters ◽  
Best Fit

 Hemoglobin level is a continuous variable. So, it follows some theoretical probability distribution Normal, Log-normal, Gamma and Weibull distribution having two parameters. There is low variation in observed and expected frequency of Normal distribution in bar diagram. Similarly, calculated value of chi-square test (goodness of fit) is observed which is lower in Normal distribution. Furthermore, plot of PDFof Normal distribution covers larger area of histogram than all of other distribution. Hence Normal distribution is the best fit to predict the hemoglobin level in future.

scholarly journals Outcomes Related to Percutaneous Nephrostomies (PCN) in Malignancy-Associated Ureteric Obstruction: A Systematic Review of the Literature

2021 ◽  
Vol 10 (11) ◽  
pp. 2354
Author(s):  
Francesca J. New ◽  
Sally J. Deverill ◽  
Bhaskar K. Somani
Keyword(s):  
Quality Of Life ◽  
Advanced Cancer ◽  
Previous Treatment ◽  
Cochrane Library ◽  
Cancer Type ◽  
Ureteric Obstruction ◽  
Survival Times ◽  
Advanced Malignancies ◽  
The Impact

Background: Malignant ureteric obstruction occurs in a variety of cancers and has been typically associated with a poor prognosis. Percutaneous nephrostomy (PCN) can potentially help increase patient longevity by establishing urinary drainage and treating renal failure. Our aim was to look at the outcomes of PCN in patients with advanced cancer and the impact on the patients’ lifespan and quality of life. Materials and Methods: A literature review was carried out for articles from 2000 to 2020 on PCN in patients with advanced malignancies, using MEDLINE, EMBASE, Scopus, CINAHL, Cochrane Library, clinicaltrials.gov, and Google Scholar. All English-language articles reporting on a minimum of 20 patients who underwent PCN for malignancy-associated ureteric obstruction were included. Results: A total of 21 articles (1674 patients) met the inclusion criteria with a mean of 60.2 years (range: 21–102 years). PCN was performed for ureteric obstruction secondary to urological malignancies (n = −633, 37.8%), gynaecological malignancies (n = 437, 26.1%), colorectal and GI malignancies (n = 216, 12.9%), and other specified malignancies (n = 205, 12.2%). The reported mean survival times varied from 2 to 8.5 months post PCN insertion, with an average survival time of 5.6 months, which depended on the cancer type, stage, and previous treatment. Conclusions: Patients with advanced malignancies who need PCN tend to have a survival rate under 12 months and spend a large proportion of this time in the hospital. Although the advent of newer chemotherapy and immunotherapy options has changed the landscape of managing advanced cancer, decisions on nephrostomy must be balanced with their survival and quality of life, which must be discussed with the patient.

scholarly journals A Universal Model for the Log-Normal Distribution of Elasticity in Polymeric Gels and Its Relevance to Mechanical Signature of Biological Tissues

Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 64
Author(s):  
Arnaud Millet
Keyword(s):  
Elastic Modulus ◽  
Normal Distribution ◽  
Biological Tissues ◽  
Force Microscopy ◽  
Polymeric Gels ◽  
Atomic Force ◽  
Clear Explanation ◽  
Log Normal ◽  
Log Normal Distribution

The mechanosensitivity of cells has recently been identified as a process that could greatly influence a cell’s fate. To understand the interaction between cells and their surrounding extracellular matrix, the characterization of the mechanical properties of natural polymeric gels is needed. Atomic force microscopy (AFM) is one of the leading tools used to characterize mechanically biological tissues. It appears that the elasticity (elastic modulus) values obtained by AFM presents a log-normal distribution. Despite its ubiquity, the log-normal distribution concerning the elastic modulus of biological tissues does not have a clear explanation. In this paper, we propose a physical mechanism based on the weak universality of critical exponents in the percolation process leading to gelation. Following this, we discuss the relevance of this model for mechanical signatures of biological tissues.

scholarly journals Streptococcal pharyngitis in general practice. 1. Some unusual features of the epidemiology

1992 ◽  
Vol 109 (2) ◽  
pp. 181-189 ◽  
Author(s):  
P. M. Higgins
Keyword(s):  
Sore Throat ◽  
Age Distribution ◽  
Positive Culture ◽  
Streptococcal Pharyngitis ◽  
Group A Streptococci ◽  
Upper Respiratory Tract ◽  
Acute Infections ◽  
Group A ◽  
Upper Respiratory ◽  
Highly Correlated

SUMMARYThis report is based on a study of acute infections of the upper respiratory tract in 1965 and detailed records of such infections in 1963 and 1964. A change from illnesses mainly yielding viruses to illnesses mainly yielding group A streptococci was noted around the age of 5 years. A positive culture for group A streptococci in patients over 4 years of age was highly correlated with a complaint of sore throat and with serological evidence of streptococcal infection. A bimodal age distribution curve for pharyngitis associated with a positive culture for group A streptococci was consistently noted. The incidence was highest in children aged 5–9 but a second smaller peak occurred among adults in the 30–39 age group. The evidence suggests that being female increases the risk of acquiring group A streptococci and of experiencing sore throat.

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