WordNet

a common nonmetallic element that is normally a colorless odorless tasteless inert diatomic gas; constitutes 78 percent of the atmosphere by volume; a constituent of all living tissues (同)N, atomic number 7
the chief solid component of mammalian urine; synthesized from ammonia and carbon dioxide and used as fertilizer and in animal feed and in plastics (同)carbamide

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『窒素』(気体元素;化学記号は『N』)
尿素(にょうそ)

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/10/17 04:08:54」(JST)

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The liver produces urea in the urea cycle as a waste product of the digestion of protein. Normal human adult blood should contain between 6 to 20 mg of urea nitrogen per 100 ml (6–20 mg/dL) of blood. Individual laboratories may have different reference ranges as the procedure may vary.^[1]^[2]

Interpretation

Blood urea nitrogen (BUN) is an indication of renal (kidney) health. Normal ranges 1.8-7.1 mmol/L.

The main causes of an increase in BUN are: high protein diet, decrease in glomerular filtration rate (GFR) (suggestive of renal failure) and in blood volume (hypovolemia), congestive heart failure, gastrointestinal hemorrhage,^[3] fever and increased catabolism. Hypothyroidism can cause both decreased GFR and hypovolemia, however BUN-to-creatinine ratio has been found to be lowered in hypothyroidism and raised in hyperthyroidism.

The main causes of a decrease in BUN are severe liver disease, anabolic state, and syndrome of inappropriate antidiuretic hormone.^[3]

Reference ranges for blood tests, comparing urea (yellow at right) to other blood constituents.

Another cause of a decreased BUN is ornithine transcarbamylase deficiency, which is a genetic disorder inherited in an X-linked recessive pattern. OTC Deficiency is also accompanied by hyperammonemia and high orotic acid levels.

Units

BUN (urea-N) is mg/dL in the United States, Mexico, Italy, Austria, and Germany. Elsewhere, the concentration of urea is reported as mmol/L, generally depending on the lab.

To convert from mg/dL of blood urea nitrogen to mmol/L of urea, multiply by 0.357 (each molecule of urea having 2 nitrogens, each of molar mass 14g/mol) (BUN is the mass of nitrogen within urea/volume, not the mass of urea)

Urea [mmol/L] = BUN [mg/dL of nitrogen] x 10 [dL/L] / 14x2 [mg N/mmol urea] (the mass of nitrogen within urea is used)

convert BUN to urea in mg/dL by using following formula:

Urea [mg/dL]= BUN [mg/dL] * 2.14

(conversion factor derived by: MW of urea = 60, MW of urea nitrogen = 14x2 => 60/28 = 2.14)

factor = 1 for conversions in mmol (1 mole N2 = 2 moles N per mole of urea):

BUN [mmol/L]= urea [mmol/L]

References

^ Last page of Deepak A. Rao; Le, Tao; Bhushan, Vikas (2007). First Aid for the USMLE Step 1 2008 (First Aid for the Usmle Step 1). McGraw-Hill Medical. ISBN 0-07-149868-0.
^ Normal Lab Results from Marshal University School of Medicine
^ ^a ^b Longo et al., Harrison's Principles of Internal Medicine, 18th ed., p.611

External links

UpToDate Contents

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1. 腎機能の評価 assessment of kidney function
2. 尿素サイクル障害：臨床的特徴および診断 urea cycle disorders clinical features and diagnosis
3. 尿素サイクル障害：管理 urea cycle disorders management
4. 急性腎障害（急性腎不全）におけるナトリウム（FENa）、尿素（FEUrea）、およびその他分子の排泄率 fractional excretion of sodium urea and other molecules in acute kidney injury acute renal failure
5. 低ナトリウム血症を有する成人の評価 evaluation of adults with hyponatremia

English Journal

Imaging of reactive oxygen species using [(3)H]hydromethidine in mice with cisplatin-induced nephrotoxicity.

Takai N1, Abe K, Tonomura M, Imamoto N, Fukumoto K, Ito M, Momosaki S, Fujisawa K, Morimoto K, Takasu N, Inoue O.
EJNMMI research.EJNMMI Res.2015 Dec;5(1):116. doi: 10.1186/s13550-015-0116-0. Epub 2015 Jul 11.
BACKGROUND: Reactive oxygen species (ROS) have been implicated in cisplatin-induced nephrotoxicity. The aim of this study was to investigate the potential of using [(3)H]-labeled N-methyl-2,3-diamino-6-phenyl-dihydrophenanthridine ([(3)H]hydromethidine) for ex vivo imaging of regional ROS overproduc
PMID 26160497

Carbon bead-supported nitrogen-enriched and Cu-doped carbon nanofibers for the abatement of NO emissions by reduction.

Bhaduri B1, Verma N2.
Journal of colloid and interface science.J Colloid Interface Sci.2015 Nov 1;457:62-71. doi: 10.1016/j.jcis.2015.06.047. Epub 2015 Jun 30.
Carbon nanofibers (CNFs) were grown over highly porous (∼1750m(2)/g-surface area) carbon beads (∼0.8mm), using catalytic chemical vapor deposition (CVD). The carbon beads were produced by the pre-oxidation, carbonization and activation of the phenolic beads that were synthesized using the suspen
PMID 26151568

Effects of water matrix on virus inactivation using common virucidal techniques for condensate urine disinfection.

Zuo X1, Chu X1, Hu J2.
Chemosphere.Chemosphere.2015 Oct;136:118-24. doi: 10.1016/j.chemosphere.2015.04.083. Epub 2015 May 15.
Three common virucidal techniques (chlorine, UV and UV/TiO2) were applied to inactivate virus (MS2 and Phi X174) in condensate water after the evaporation of source-separated urine for reclaimed water. The inactivation efficiencies were compared with the results of previous studies, with the emphasi
PMID 25966330

Japanese Journal

Revised System to Evaluate Measurement of Blood Chemistry Data From the Japanese National Health and Nutrition Survey and Prefectural Health and Nutrition Surveys

Nakamura Masakazu,Kiyama Masahiko,Kitamura Akihiko,Ishikawa Yoshinori,Sato Shinichi,Noda Hiroyuki,Yoshiike Nobuo
Journal of Epidemiology, 2013
… lipoprotein cholesterol (mg/dL), 10.4% for triglycerides (mg/dL), 6.6% for total protein (g/dL), 7.6% for albumin (g/dL), 10.8% for creatinine (mg/dL), 6.5% for glucose (mg/dL), 9.7% for γ-glutamyl transpeptidase (U/L), 7.7% for uric acid (mg/dL), 8.7% for urea nitrogen (mg/dL), 9.2% for aspartate aminotransferase (U/L), 9.5% for alanine aminotransferase (U/L), and 6.5% for hemoglobin A1c (%).<BR>Conclusions: This monitoring system was established to assist health professionals in evaluating the continuity and …
NAID 130001913530

Serum Blood Urea Nitrogen and Plasma Brain Natriuretic Peptide and Low Diastolic Blood Pressure Predict Cardiovascular Morbidity and Mortality Following Discharge in Acute Decompensated Heart Failure Patients

CHEN Chun-Yen,YOSHIDA Akemi,ASAKURA Masanori,HASEGAWA Takuya,TAKAHAMA Hiroyuki,AMAKI Makoto,FUNADA Akira,ASANUMA Hiroshi,YOKOYAMA Hiroyuki,KIM Jiyoong,KANZAKI Hideaki,KITAKAZE Masafumi
Circulation journal : official journal of the Japanese Circulation Society 76(10), 2372-2379, 2012-09-25
… The most important predictors of re-hospitalization were serum blood urea nitrogen (BUN; …
NAID 10030874757

Blood Urea Nitrogen as an Integrated Biomarker for Hospitalized Heart Failure

SATO Naoki
Circulation journal : official journal of the Japanese Circulation Society 76(10), 2329-2330, 2012-09-25
NAID 10030874559

「尿素窒素」

Blood urea nitrogen
	Diagnostics
	Urea
MeSH	D001806
LOINC	6299-2, 59570-2, 12961-9, 12963-5, 12962-7

　　[★]

英: urea nitrogen UN
同: 血中尿素窒素 blood urea nitrogen BUN
関: 尿素、ウレアーゼ、クレアチニン、残余窒素

意義

血中の尿素
尿素は肝臓で尿素サイクルによって産生される。

尿素窒素を構成する要素 LAB

産生：腎前性因子(食事蛋白摂取量、組織崩壊、胃腸管出血)、循環血液量の異常(脱水、血液濃縮)
排泄：腎性因子：腎機能
その他：チアジド系利尿薬、エタクリン酸、テトラサイクリン系抗菌薬(腎障害作用、蛋白異化作用を有する)で中等度上昇。成長ホルモンやタンパク質同化ホルモンにより低下。

基準値

8-20 mg/dL (QB)

単位の変換：1 mg/dL = 10 x 10^-3 g/L = 10^-2 / 28 mol/L = 0.0003751 mol/L = 0.3751 mmol/L

N2 = 28 g/L

判別(検査値の本より)

3g/日以下(減少)

[高頻度]肝不全(肝硬変末期など)、高度腎不全、低蛋白食、妊娠
[可能性]飢餓

15g/日以上(増加)

[高頻度]高蛋白食、蛋白異化の亢進する病態(悪性腫瘍、感染、外傷、手術など)
[可能性]コルチコステロイド、利尿薬、テトラサイクリンなどの薬物投与

「UN」

　　[★]

「nitrogen」

　　[★]

n.

窒素

関: N、N2、nitric

[firstaid-1] Last page of Deepak A. Rao; Le, Tao; Bhushan, Vikas (2007). First Aid for the USMLE Step 1 2008 (First Aid for the Usmle Step 1). McGraw-Hill Medical. ISBN 0-07-149868-0.

[Marshall-2] Normal Lab Results from Marshal University School of Medicine

[:0-3] Longo et al., Harrison's Principles of Internal Medicine, 18th ed., p.611

リンク元	「尿素窒素」「UN」
関連記事	「nitrogen」

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案内

案内

urea nitrogen