Practical Approaches to the Determination of the Sample Size in Clinical Studies

Demirel, Neslihan; Gürler, Selma

doi:10.9775/kvfd.2009.527

Cited by 3 publications

(3 citation statements)

References 10 publications

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“…Sample sizes were given six for one-tailed and seven for two-tailed in pairs t-test for 1-β ¼ 0.80 power level in d ¼ 0.5 values for 1% significance level. 9 According to the animal ethics committee directive of Gazi University, the most appropriate animal model must be selected and the minimum number of animals, from which the precise information and results can be obtained, must be used. 10 According to these principles and power analyses, the maximum number of animals has been selected within the framework of the ethical council directives of Gazi University.…”

Section: Animalsmentioning

confidence: 99%

Can Sericin Prove Useful as a Pleurodesis Agent or Tissue Glue?

Yazicioğlu¹,

Demırağ

Alıcı

et al. 2016

Thorac cardiovasc Surg

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Sericin is a natural, gum-like, macromolecule protein, synthesized from silkworms for the formation of cocoon shells. The aim of the present study is to describe the effects of sericin when used for pleurodesis and/or as tissue glue. Adult, male, 12-week-old Wistar albino rats, weighing 257 to 395 g were used in the present study ( = 12). The animals were randomly divided into two equal groups as the sericin and the control group. After intramuscular administration of the anesthetic agent, the rats were intubated and mechanically ventilated. A left thoracotomy was performed and 30 mg sericin powder was instilled into the thoraxes of the sericin group. The remaining rats were allocated to a sham thoracotomy group. The animals were housed in individual cages, fed ad-libitum, and sacrificed 8 days after. After sacrifice, the left hemithoraxes were removed en bloc and underwent histopathologic examination. Masson trichrome staining was applied on the visceral pleura sections of all the animals. Each animal specimen ( = 6, 100%) in the control group showed minimal collagen deposition, while only one rat (16.67%) in the sericin group had minimal collagen deposition. However, in the sericin group, five animals (83.33%) showed dense collagen deposition, fibroblastic activity, and fibrosis. According to the test method, independent -test, developing fibroblastic activity and fibrosis are statistically significant between the two groups ( < 0.01). There were no foreign-body reactions and no evidence of biological glue on the specimens in the sericin group. The rats in the sericin group had lower inflammatory reactions compared with those in the control group. Emphysema was observed in two rats (33.33%) in the sericin group and in four rats (66.67%) in the control group. Therefore, sericin was found to be associated with an increase in fibroblastic activity and fibrosis in visceral pleura without exerting any adverse effect on the lung parenchyma. Sericin is a new and researchable protein for chest diseases and thoracic surgery. To develop an effect of dense collagen deposition, fibroblastic activity, and fibrosis in the visceral pleura, without significant adverse effects, is remarkable. Therefore, sericin may be useful as a pleurodesis agent or natural biological glue in the future. Sericin treatment can add value to the disciplines of pulmonology and thoracic surgery.

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Section: Animalsmentioning

confidence: 99%

Can Sericin Prove Useful as a Pleurodesis Agent or Tissue Glue?

Yazicioğlu¹,

Demırağ

Alıcı

et al. 2016

Thorac cardiovasc Surg

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“…Literatürde uygun örneklem genişliğinin belirlenmesi ile ilgili yapılmış birçok çalışma bulunmaktadır. [1][2][3][4][5][6] Araştırmacılar, güç analizi yöntemlerini kullanarak örneklem genişliğini belirlerken karmaşık matematiksel ifadeler nedeni ile oldukça zorlanmaktadırlar. Bu nedenle, özellikle son yıllarda, örneklem genişliğinin belirlenmesine yönelik çeşitli hazır yazılımlar (nQuery Advisor, PASS vb.)…”

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Practical Approaches For Determination Of Sample Size In Paired Case-Control Studies

Demirel¹,

Oruç²,

Gürler³

2016

Turkiye Klinikleri J Biostat

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Neslihan DEMİREL ve ark.EŞLEŞTİRİLMİŞ DURUM-KONTROL ÇALIŞMALARINDA ÖRNEKLEM GENİŞLİĞİNİN BELİRLENMESİ...Turkiye Klinikleri J Biostat 2016;8(1) 36 ORİJİNAL ARAŞTIRMA ORIGINAL RESEARCH linik araştırmalar genellikle yeni bir ilaç veya tıbbi aletin canlılar-da kullanımının etkin ve güvenilir olup olmadığını göstermek için yapılır. Bu nedenle tıp ve veteriner hekimlik alanlarında fazla sayıda deneysel çalışma yapılmaktadır. Maliyetli ve zaman alıcı olan bu ça-lışmalarda sonuçların güvenilir olabilmesi için istatistik yöntemler bakı-mından iyi tasarlanmaları gerekmektedir. Bir bilimsel çalışmanın her aşa-ması dikkatli ve özenli bir şekilde belirlenmelidir. Anahtar Kelimeler: McNemar testi; testin gücü; istatistiksel veri analizi; bağımlı iki örneklem ABSTRACT Objective: Cross-over design or paired case control studies that are using in clinical studies are the methods of design of experiments which requires dependent samples. The problem of sample size determination is generally difficult step of planning the statistical design. The aim of this study is to provide the researchers a practical approach for determining the sample size in paired control studies. Material and Methods: In this study, determination of sample size is mentioned in detail identification for the most common method Mc Nemar Test in paired (dependent) samples. Sample sizes are calculated according to different significance and power level combination. Results: Sample sizes were calculated for McNemar test which is used paired samples studies, for the combination of different power levels (1-β) and significance levels (α). The results are presented in tables. Conclusion: Appropriate sample sizes for the cross-over design or paired-control studies used in clinical studies were calculated and presented in tables. These tables are to provide the researchers a practical approach for determining the sample size in paired control studies.

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“…13,14 While there have been trials concerning sample size and power analysis in different disciplines in Turkey in recent years, to the best of our knowledge, no trials have been conducted in the field of Orthopedics and Traumatology. [15][16][17] In the current study, the main aim was to assess the original articles in the Turkey-centered SCIE (Science Citation Index Expanded) indexed orthopedics and traumatology journals published between January 2010 and May 2014 to determine whether or not they had adequate power (β <0.20) at small, medium or large effect size levels and whether or not they were performed with adequate sample size according to their effect size.…”

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confidence: 99%