#1
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CGH -ñðàâíèòåëüíàÿ ãåíîìíàÿ ãèáðèäèçàöèÿ
Çäðàâñòâóéòå, Áîðèñ Àëåêñàíäðîâè÷! Ñêàæèòå, ïîæàëóéñòà, îïðåäåëÿåò ëè ìåòîä ÑGH íàëè÷èå ó ýìáðèîíà òðèïëîèäèè? Äåëî â òîì, ÷òî ó ìåíÿ áûëî 3 çàìåðøèå áåðåìåííîñòè. Îäèí ðàç ïðè÷èíà òðèïëîèäèÿ, â äâóõ äðóãèõ àíàëèç íå ïðîâîäèëñÿ, ïîòîìó ÷òî áûë î÷åíü ìàëåíüêèé ñðîê. Íàñêîëüêî âîîáùå âåëèê øàíñ ïîâòîðåíèÿ èìåííî òðèïëîèäèè? Ñïàñèáî çà îòâåò.
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#2
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Åñòåñòâåííî , äà.
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#3
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Áîðèñ Àëåêñàíäðîâè÷,
Íà àíãëîÿçû÷íûõ ñàéòàõ åñòü èíôîðìàöèÿ, ÷òî íå îïðåäåëÿåò. Íàïðèìåð, âîò çäåñü: A. Array CGH cannot detect “balanced” chromosome rearrangements such as reciprocal translocations and inversions and polyploidy. However, ~40% of patients with apparently balanced de novo rearrangements and abnormal clinical phenotypes will have imbalances detected by arrays. Array CGH will also detect imbalances which are the unbalanced products of balanced parental rearrangements. The follow up studies are designed to confirm these. aCGH will not detect either mixtures of normal and abnormal cells (mosaicism) where the proportion of abnormal cells is < 30%, or triploidy, but both of these are extremely rare conditions and, if suspected, can be tested with other methods. Öèòàòà îòñþäà: [Ññûëêè äîñòóïíû òîëüêî çàðåãèñòðèðîâàííûì ïîëüçîâàòåëÿì ] Èíòåðåñíî, êòî ïðàâ? |
#4
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Öèòàòà:
Ìåòîä äåéñòâèòåëüíî "óâèäèò" íåêðàòíîå 23-ì èçìåíåííîå êîëè÷åñòâî õðîìîñîì, à ãà- äè- òåòðà è ò.ä. áóäåò èíòåðïðåòèðîâàòü êàê íîðìó. Ê ñîæàëåíèþ, ÿ ïîòîðîïèëñÿ ñ îòâåòîì óïóñòèâ èç âíèìàíèÿ ýòîò ìîìåíò. |
#5
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Èñêëþ÷èòü ãà-, òðè-, òåòðà- è òä. ïëîèäíîñòü äîñòàòî÷íî ñëîæíî, ò.ê. ïðè îöåíêå ìîðôîëîãèè íà 1 äåíü ïîäñ÷åò ïîëÿðíûõ òåëåö äàëåêî íå âñåãäà áóäåò ñîîòâåòñòâîâàòü èñòèííîé ïëîèäíîñòè ýìáðèîíà, êàê âïðî÷åì è ïðîâåäåíèå FISH - èññëåäîâàíèÿ áëàñòîìåðà ýìáðèîíà 3-ãî äíÿ (ñ ó÷åòîì ìîçàèöèçìà) âðÿä ëè äàñò òî÷íûé îòâåò íà ïîñòàâëåííûé âîïðîñ.
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#6
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Íåìíîãî "ïîãðóçèëàñü" â âîïðîñ è íàøëà âîò ÷òî:
* Polyploidy Detection: Array-CGH cannot detect some triploidies, such 69,XXX, and tetraploidies, such 92,XXXX or 92,XXYY, but it does detect trisomy for gender triploidy 69,XXY and tetraploidy 92,XXXY and 92,XYYY. In addition, any embryo with polyploidy not detectable by array CGH will nonetheless be classified as aneuploid if there is another aneuploidy present in the cell. To determine how many of these pure polyploidies are missed by array-CGH, our database of embryos analyzed by FISH (using 9–12 probes) was queried. We found that 7.5% (6,898/92,018) embryos were polyploid or haploid. However, the majority of these embryos had other abnormalities detectable by CGH or array-CGH, and only 2.3% (2,136/91,073) of the embryos was homogeneously polyploid or haploid. Of those homogeneously polyploid or haploid, only 1.7% (1,587/92,018) were not detectable by array-CGH (i.e., 69,XXX or 92,XXYY). Furthermore, 87% of these embryos were arrested or showed abnormal morohology and consequently would not have been transferred to the patient. (From Gutierrez Mateo et al. 2011, Fertil Steril, 95:953–8) Öèòàòà îòñþäà: [Ññûëêè äîñòóïíû òîëüêî çàðåãèñòðèðîâàííûì ïîëüçîâàòåëÿì ] Ò.å. ïîëó÷àåòñÿ, ÷òî â òåîðèè ýòîò ìåòîä ðàñïîçíàòü ïîëèïëîèäèþ íå ìîæåò, íî íà ïðàêòèêå îòñåèâàåò ýòè ýìáðèîíû ïî êàêèì-òî äîïîëíèòåëüíûì ïðèçíàêàì. Êàê-òî òàê. |
#7
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ß óæå ãîâîðèë âûøå ÷òî ýòî ñäåëàòü äåéñòâèòåëüíî äîñòàòî÷íî ñëîæíî. ×àùå âñåãî îöåíêà ïðîâîäèòñÿ ïî ìîðôîëîãè÷åñêèì êðèòåðèÿì (êîëè÷åñòâó ïîëÿðíûõ òåëåö â 1-é äåíü), îäíàêî íå âñåãäà íàëè÷èå îäíîãî ïîëÿðíîãî òåëüöà ãîâîðèò î ãàïëîèäíîì íàáîðå (ò.å. âðåìÿ îöåíêè ìîæåò âëèÿòü íà èíòåðïðåòàöèþ), èíîãäà ïðè íàëè÷èè òðåõ ïîëÿðíûõ òåëåö (îñîáåííî ïðè èõ ðàçëè÷íîé âåëè÷èíå) ôðàãìåíòàöèÿ îäíîãî òåëüöà ìîæåò áûòü ðàñöåíåíà êàê äâà ðàçíûõ è òä, è òä, è òä. Âîïðîñû äèàãíîñòèêè (ÿ èìåþ ââèäó 100% îáúåêòèâíîñòü) ñêîðåå èç îáëàñòè òåîðèè, ò.ê. ìîæíî èñïîëüçîâàòü êîìáèíàöèþ ðàçëè÷íûõ ìåòîäîâ (ìîðôîëîãèþ è äèàãíîñòèêó ïîëÿðíûõ òåëåö, FISH äèàãíîñòèêó áëàñòîìåðà ýìáðèîíâ 3-ãî äíÿ (à ëó÷øå áû äâóõ) íó è CHG òðîôîáëàñòà), íî çäåñü ñòàåò âîïðîñ öåíû è öåëåñîîáðàçíîñòè (âåäü íà êàæäîì ýòàïå ïðèéäåòñÿ ÷òî-òî "îòñ÷èïûâàòü" îò ýìáðèîíà), ÷òî âðÿä áóäåò áëàãîòâîðíî âëèÿòü íà åãî äàëüíåéøåå ðàçâèòèå óæå ïðè èñêëþ÷åííûõ îòêëîíåíèÿõ îò íîðìû. Äà è çàäà÷à ñòîèò íå ïðîâåäåíèè êàê ìîæíî áîëüøåãî êîëè÷åñòâà èññëåäîâàíèé, à â ïîïûòêå áàëàíñèðîâàòü ìåæäó íåîáõîäèìîñòüþ è äîñòàòî÷íîñòüþ äëÿ äîñòèæåíèÿ îïòèìàëüíîãî ðåçóëüòàòà. Òåîðåòèçèðîâàòü êîíå÷íî ïðîñòî , à íà ïðàêòèêå
Êàê-òî òàê. |
#8
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Åñëè ãîâîðèòü î ìîðôîëîãè÷åñêèõ êðèòåðèÿõ äëÿ 1-ãî äíÿ ðàçâèòèÿ ýìáðèîíîâ, òî áîëüøåå âíèìàíèå ñòîèò óäåëèòü êîë-âó ïðîíóêëåóñîâ â çèãîòå. Òê â ñòàíäàðòíîé ïðàêòèêå ëàáîðàòîðèè ÝÊÎ íå êóëüòèâèðóþò ýìáðèîíû ñ êîë-âîì ïðîíóêëåóñîâ íåðàâíîì 2, ýòî ïîçâîëÿåò ñíèçèòü âåðîÿòíîñòü ïåðåíîñà ãàïëîèäíûõ è ïîëèïëîèäíûõ ýìáðèîíîâ.
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#9
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Ò.å. ÿ ïðàâèëüíî ïîíèìàþ, ÷òî äåôåêòíûé ýìáðèîí ñêîðåå âñåãî áóäåò îòáðàêîâàí â ëàáîðàòîðèè åùå äî ïðîâåäåíèÿ äèàãíîñòèêè, ïîòîìó ÷òî ó íåãî áóäåò íåïðàâèëüíîå êîëè÷åñòâî ÿäåð?
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#10
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#11
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Ñïàñèáî áîëüøîå çà ðàçúÿñíåíèå!
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