<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>2224-5421</journal-id>
<journal-title><![CDATA[Revista Cubana de Química]]></journal-title>
<abbrev-journal-title><![CDATA[Rev Cub Quim]]></abbrev-journal-title>
<issn>2224-5421</issn>
<publisher>
<publisher-name><![CDATA[Ediciones UO, Universidad de Oriente]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S2224-54212019000200224</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Purificación y caracterización de gonadotropina coriónica humana para uso diagnóstico]]></article-title>
<article-title xml:lang="en"><![CDATA[Purification and characterization of human chorionic gonadotropin for diagnosis]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Melchor-Rodríguez]]></surname>
<given-names><![CDATA[Antonio]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Zúñiga-Rosales]]></surname>
<given-names><![CDATA[Yaíma]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Zulueta-Rodríguez]]></surname>
<given-names><![CDATA[Orlando]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Hernández-Pérez]]></surname>
<given-names><![CDATA[Liliana]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[López-Cisnero]]></surname>
<given-names><![CDATA[Raquel]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Centro de Inmunoensayo  ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Cuba</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Centro Nacional de Genética Médica  ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Cuba</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>08</month>
<year>2019</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>08</month>
<year>2019</year>
</pub-date>
<volume>31</volume>
<numero>2</numero>
<fpage>224</fpage>
<lpage>245</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://scielo.sld.cu/scielo.php?script=sci_arttext&amp;pid=S2224-54212019000200224&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://scielo.sld.cu/scielo.php?script=sci_abstract&amp;pid=S2224-54212019000200224&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://scielo.sld.cu/scielo.php?script=sci_pdf&amp;pid=S2224-54212019000200224&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[RESUMEN En Cuba, el UMELISA HCG, producido por el Centro de Inmunoensayo, detecta la presencia de gonadotropina coriónica humana. Con el objetivo de purificar y caracterizar gonadotropina coriónica humana (hCG) para uso diagnóstico, se desarrolló un procedimiento para su obtención a partir de orina de gestantes, con una etapa de captura y una de purificación por cromatografía de inmunoafinidad, empleando un anticuerpo monoclonal anticadena &#946; hCG. La mayor masa de hCG en el precipitado (74,27 %) se obtuvo al 50 % de saturación del (NH4)2SO4, 22 (C y 3 h de reposo. La actividad específica fue 12 417,65 UI/mg. El PAGE-SDS mostró las bandas de las cadenas &#945; y &#946;, con movilidad similar al control. La pureza por densitometría fue 97,3 %. Por filtración en gel se obtuvo una masa molar de 40 kDa. Con la metodología empleada se obtuvo gonadotropina coriónica humana con la calidad requerida para la obtención de los reactivos biológicos del UMELISAHCG.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[ABSTRACT In Cuba, the UMELISA HCG, produced by the Immunoassay Center, detects the presence of human chorionic gonadotropin. With the aim to purify and characterize human chorionic gonadotropin (hCG) for diagnostic use, was developed a procedure for its purification from the urine of pregnant women, with a capture stage and a phase of immune affinity chromatography, using a monoclonal antibody anti-chain &#946; hCG. The highest mass of hCG (74,27 %) in the precipite was obtained at 50 % saturation of (NH4)2SO4, 22 (C and 3 h of rest,. The specific activity was 12 417,65 IU/mg. PAGE-SDS showed the bands of the &#945; and &#946; chains of the hormone, with similar mobility to the control. The purity by densitometry was 97,3 %. By gel filtration a molar mass of 40 kDa was obtained. Using this procedure human chorionic gonadotropin with the required quality to get biological reagents for the UMELISA HCG was obtain.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[gonadotropina coriónica]]></kwd>
<kwd lng="es"><![CDATA[cromatografía de afinidad]]></kwd>
<kwd lng="es"><![CDATA[inmunoensayo]]></kwd>
<kwd lng="es"><![CDATA[orina]]></kwd>
<kwd lng="en"><![CDATA[chorionic gonadotropin]]></kwd>
<kwd lng="en"><![CDATA[affinity chromatography]]></kwd>
<kwd lng="en"><![CDATA[immunoassay]]></kwd>
<kwd lng="en"><![CDATA[urine]]></kwd>
</kwd-group>
</article-meta>
</front><back>
<ref-list>
<ref id="B1">
<label>1</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[FOURNIER]]></surname>
<given-names><![CDATA[T]]></given-names>
</name>
<name>
<surname><![CDATA[GUIBOURDENCHE]]></surname>
<given-names><![CDATA[J]]></given-names>
</name>
<name>
<surname><![CDATA[EVAIN BRION]]></surname>
<given-names><![CDATA[D]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Review: hCGs: different sources of production, different glycoforms and functions]]></article-title>
<source><![CDATA[Placenta]]></source>
<year>2015</year>
<volume>36</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>S60-5</page-range></nlm-citation>
</ref>
<ref id="B2">
<label>2</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[COLE]]></surname>
<given-names><![CDATA[LA]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[New discoveries on the biology and detection of human chorionic gonadotropin]]></article-title>
<source><![CDATA[Reprod Biol Endocrinol]]></source>
<year>2009</year>
<volume>7</volume>
<numero>8</numero>
<issue>8</issue>
</nlm-citation>
</ref>
<ref id="B3">
<label>3</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[BOGART]]></surname>
<given-names><![CDATA[M]]></given-names>
</name>
<name>
<surname><![CDATA[PANDIAN]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[JONES]]></surname>
<given-names><![CDATA[O]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Abnormal maternal serum chorionic gonadotrophin levels in pregnancies with fetal chromosome abnormalities]]></article-title>
<source><![CDATA[Prenat Diagn]]></source>
<year>1987</year>
<volume>7</volume>
<page-range>623-30</page-range></nlm-citation>
</ref>
<ref id="B4">
<label>4</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[CROSSLEY]]></surname>
<given-names><![CDATA[J. A.]]></given-names>
</name>
<name>
<surname><![CDATA[AITKEN]]></surname>
<given-names><![CDATA[DA]]></given-names>
</name>
<name>
<surname><![CDATA[CONNOR]]></surname>
<given-names><![CDATA[J. M]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Prenatal screening for chromosome abnormalities using maternal serum chorionic gonadotrophin, alpha-fetoprotein, and age]]></article-title>
<source><![CDATA[Prenat diagn]]></source>
<year>1991</year>
<page-range>83-101</page-range></nlm-citation>
</ref>
<ref id="B5">
<label>5</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[KAGAN]]></surname>
<given-names><![CDATA[K. O]]></given-names>
</name>
<name>
<surname><![CDATA[SONEK]]></surname>
<given-names><![CDATA[J]]></given-names>
</name>
<name>
<surname><![CDATA[WAGNER]]></surname>
<given-names><![CDATA[P]]></given-names>
</name>
<name>
<surname><![CDATA[HOOPMANN]]></surname>
<given-names><![CDATA[M]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Principles of first trimester screening in the age of non-invasive prenatal diagnosis: screening for chromosomal abnormalities]]></article-title>
<source><![CDATA[Arch Gynecol Obstet]]></source>
<year>2017</year>
<volume>296</volume>
<numero>4</numero>
<issue>4</issue>
<page-range>645-51</page-range></nlm-citation>
</ref>
<ref id="B6">
<label>6</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[CAVORETTO]]></surname>
<given-names><![CDATA[P]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Nuchal translucency measurement, free &#946;-hCG and PAPP-A concentrations in IVF/ICSI pregnancies: systematic review and meta-analysis]]></article-title>
<source><![CDATA[Prenat Diagn]]></source>
<year>2017</year>
<volume>37</volume>
<numero>6</numero>
<issue>6</issue>
<page-range>540-55</page-range></nlm-citation>
</ref>
<ref id="B7">
<label>7</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[KOR ANANTAKUL]]></surname>
<given-names><![CDATA[O]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Normative weight-adjusted models for the median levels of first trimester serum biomarkers for trisomy 21 screening in a specific ethnicity]]></article-title>
<source><![CDATA[PLoS One]]></source>
<year>2017</year>
<volume>12</volume>
<numero>8</numero>
<issue>8</issue>
</nlm-citation>
</ref>
<ref id="B8">
<label>8</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[EYSBOUTS]]></surname>
<given-names><![CDATA[Y]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Serum Human Chorionic Gonadotropin Normogram for the Detection of Gestational Trophoblastic Neoplasia]]></article-title>
<source><![CDATA[Int J Gynecol Cancer]]></source>
<year>2017</year>
<volume>27</volume>
<numero>5</numero>
<issue>5</issue>
<page-range>1035-41</page-range></nlm-citation>
</ref>
<ref id="B9">
<label>9</label><nlm-citation citation-type="">
<collab>UMELISA HCG</collab>
<source><![CDATA[Centro de Inmunoensayo]]></source>
<year>2014</year>
</nlm-citation>
</ref>
<ref id="B10">
<label>10</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[MELCHOR RODRÍGUEZ]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Purification of Human Chorionic Gonadotropin from Pregnancy Urine by Immunoaffinity Chromatography Using a Monoclonal Antibody Anti-&#946; Chain hCG]]></article-title>
<source><![CDATA[HYBRIDOMA]]></source>
<year>2005</year>
<volume>24</volume>
<numero>5</numero>
<issue>5</issue>
<page-range>258-2 62</page-range></nlm-citation>
</ref>
<ref id="B11">
<label>11</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[LOWRY]]></surname>
<given-names><![CDATA[O.]]></given-names>
</name>
<name>
<surname><![CDATA[ROSEBROUGH]]></surname>
<given-names><![CDATA[N. J.]]></given-names>
</name>
<name>
<surname><![CDATA[FARR]]></surname>
<given-names><![CDATA[A. L.]]></given-names>
</name>
<name>
<surname><![CDATA[RANDALL]]></surname>
<given-names><![CDATA[R. J]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Protein measurement with the folin phenol reagent]]></article-title>
<source><![CDATA[J Biol Chem]]></source>
<year>1951</year>
<volume>193</volume>
<page-range>265-75</page-range></nlm-citation>
</ref>
<ref id="B12">
<label>12</label><nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[CHÁVEZ]]></surname>
<given-names><![CDATA[M]]></given-names>
</name>
<name>
<surname><![CDATA[DÍAZ]]></surname>
<given-names><![CDATA[J]]></given-names>
</name>
<name>
<surname><![CDATA[PÉREZ]]></surname>
<given-names><![CDATA[U]]></given-names>
</name>
<name>
<surname><![CDATA[DELFÍN]]></surname>
<given-names><![CDATA[J]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Purificación de Proteínas]]></article-title>
<source><![CDATA[Temas de enzimología]]></source>
<year>1990</year>
<page-range>39-224</page-range><publisher-loc><![CDATA[La Habana ]]></publisher-loc>
<publisher-name><![CDATA[Universidad de La Habana]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B13">
<label>13</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[WINGFIELD]]></surname>
<given-names><![CDATA[P.T]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Protein Precipitation Using Ammonium Sulfate]]></article-title>
<source><![CDATA[Curr Protoc Protein Sci]]></source>
<year>2001</year>
<volume>13</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>APPENDIX 3: Appendix-3F</page-range></nlm-citation>
</ref>
<ref id="B14">
<label>14</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[BALUJA]]></surname>
<given-names><![CDATA[I. B]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Obtención y producción de un anticuerpo monoclonal específico a la gonadotropina coriónica humana y su aplicación en el ultramicroELISA]]></article-title>
<source><![CDATA[Rev CENIC Cien Biol]]></source>
<year>2000</year>
<volume>31</volume>
<page-range>169-72</page-range></nlm-citation>
</ref>
<ref id="B15">
<label>15</label><nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[BATISTA VIERA]]></surname>
<given-names><![CDATA[F.]]></given-names>
</name>
<name>
<surname><![CDATA[JANSON]]></surname>
<given-names><![CDATA[J. C.]]></given-names>
</name>
<name>
<surname><![CDATA[CARLSSON]]></surname>
<given-names><![CDATA[J]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Affinity Chromatography]]></article-title>
<person-group person-group-type="editor">
<name>
<surname><![CDATA[JANSON]]></surname>
<given-names><![CDATA[J-C]]></given-names>
</name>
</person-group>
<source><![CDATA[Protein Purification. Principles, High Resolution Methods, and Applications]]></source>
<year>2011</year>
<edition>3</edition>
<page-range>221-58</page-range><publisher-name><![CDATA[Ed. John Wiley &amp; Sons Inc]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B16">
<label>16</label><nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[LIZANA]]></surname>
<given-names><![CDATA[J. A]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Immunoelectrophoresis]]></article-title>
<person-group person-group-type="editor">
<name>
<surname><![CDATA[JANSON]]></surname>
<given-names><![CDATA[J. C.]]></given-names>
</name>
<name>
<surname><![CDATA[RYDÉN]]></surname>
<given-names><![CDATA[L]]></given-names>
</name>
</person-group>
<source><![CDATA[Protein Purification. Principles, High Resolution Methods, and Applications]]></source>
<year>1998</year>
<edition>2</edition>
<page-range>529-5 56</page-range><publisher-name><![CDATA[Ed. John Wiley &amp; Sons Inc]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B17">
<label>17</label><nlm-citation citation-type="">
<collab>GE</collab>
<article-title xml:lang=""><![CDATA[Healthcare Bio-Sciences AB. Chapter 5 Designing affinity media using pre-activated matrices]]></article-title>
<source><![CDATA[Affinity Chromatography Principles and Methods. GE Life Science]]></source>
<year>2007</year>
<page-range>109-12</page-range></nlm-citation>
</ref>
<ref id="B18">
<label>18</label><nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[YUKI]]></surname>
<given-names><![CDATA[Y.]]></given-names>
</name>
<name>
<surname><![CDATA[NISHIMURA]]></surname>
<given-names><![CDATA[T.]]></given-names>
</name>
<name>
<surname><![CDATA[HIRATANI]]></surname>
<given-names><![CDATA[H]]></given-names>
</name>
</person-group>
<source><![CDATA[Process for producing highly purified HCG. Patente de los EE.UU]]></source>
<year>1987</year>
</nlm-citation>
</ref>
<ref id="B19">
<label>19</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[XU]]></surname>
<given-names><![CDATA[B.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Purification of human chorionic gonadotropin from urine by membrane filtration affinity chromatography with a positively charged membrane]]></article-title>
<source><![CDATA[Protein Exp Purif]]></source>
<year>1999</year>
<volume>16</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>221-3</page-range></nlm-citation>
</ref>
<ref id="B20">
<label>20</label><nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[COLE]]></surname>
<given-names><![CDATA[L]]></given-names>
</name>
</person-group>
<source><![CDATA[hCG and Hyperglicosilated hCG Purification and analysis from serum, urine and culture fuids&#8221;. En: Human Chorionic Gonadotropin (hCG)]]></source>
<year>2010</year>
<page-range>351-3 53</page-range><publisher-name><![CDATA[Elsevier Inc]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B21">
<label>21</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[HOERMANN]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[SPOETTL]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
<name>
<surname><![CDATA[MONCAYO]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[MANN]]></surname>
<given-names><![CDATA[K]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Evidence for the presence of human chorionic gonadotropin (hCG) and free beta-subunit of hCG in the human pituitary]]></article-title>
<source><![CDATA[J Clin Endocrinol Metab]]></source>
<year>1990</year>
<volume>71</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>179-86</page-range></nlm-citation>
</ref>
<ref id="B22">
<label>22</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[GADKARI]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[DESHPANDE]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[DIGHE]]></surname>
<given-names><![CDATA[R. R]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Hyperexpression and purification of biologically active human luteinizing hormone and human chorionic gonadotropin using the methylotropic yeast, Pichia pastoris]]></article-title>
<source><![CDATA[Protein Expr Purif]]></source>
<year>2003</year>
<volume>32</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>175-84</page-range></nlm-citation>
</ref>
<ref id="B23">
<label>23</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[HO]]></surname>
<given-names><![CDATA[H. H]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Characterization of human chorionic gonadotropin in normal and abnormal pregnancies]]></article-title>
<source><![CDATA[Early Pregnancy.]]></source>
<year>1997</year>
<volume>3</volume>
<numero>3</numero>
<issue>3</issue>
<page-range>213-24</page-range></nlm-citation>
</ref>
<ref id="B24">
<label>24</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[SUTTON]]></surname>
<given-names><![CDATA[J. M]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Charge variants in serum and urine hCG]]></article-title>
<source><![CDATA[Clin Chim Acta]]></source>
<year>2004</year>
<volume>341</volume>
<numero>1-2</numero>
<issue>1-2</issue>
<page-range>199-203</page-range></nlm-citation>
</ref>
<ref id="B25">
<label>25</label><nlm-citation citation-type="">
<collab>GE</collab>
<source><![CDATA[Healthcare Bio-Sciences AB. Antibody Purification Handbook, GE Life Science]]></source>
<year>2007</year>
</nlm-citation>
</ref>
<ref id="B26">
<label>26</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[SAKAKIBARA]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Effective purification of human chorionic gonadotropin and its subunits from pregnant women's urinary peptides absorbed on reverse-phase resin]]></article-title>
<source><![CDATA[Chem Pharm Bull (Tokyo)]]></source>
<year>1990</year>
<volume>38</volume>
<numero>5</numero>
<issue>5</issue>
<page-range>1414-6</page-range></nlm-citation>
</ref>
<ref id="B27">
<label>27</label><nlm-citation citation-type="">
<collab>C0434 Sigma</collab>
<source><![CDATA[Chorionic gonadotropin human from human pregnancy urine, lyophilized powder]]></source>
<year></year>
</nlm-citation>
</ref>
<ref id="B28">
<label>28</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[BRISTOW]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[IFCC Working Group on hCG. Establishment, value assignment, and characterization of new WHO reference reagents for six molecular forms of human chorionic gonadotropin]]></article-title>
<source><![CDATA[Clin Chem]]></source>
<year>2005</year>
<volume>51</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>177-82</page-range></nlm-citation>
</ref>
<ref id="B29">
<label>29</label><nlm-citation citation-type="">
<collab>SIGMA</collab>
<source><![CDATA[Chorionic gonadotropin human. Product information]]></source>
<year></year>
</nlm-citation>
</ref>
<ref id="B30">
<label>30</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[KATO]]></surname>
<given-names><![CDATA[K.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Immunological and biological activity of different commercial preparations of human chorionic gonadotropin]]></article-title>
<source><![CDATA[Zentralbl Gynakol]]></source>
<year>2002</year>
<volume>124</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>123-7</page-range></nlm-citation>
</ref>
</ref-list>
</back>
</article>
