Frederick Hecht

Predominance of hemoglobin Gower 1 in early human embryonic development.

Hemoglobin Gower 1, the structure of which is thought to be ε4, is the predominant hemoglobin in early human embryonic life. This finding suggests that the production of ε-chains initially exceeds that of other known (α, β, γ, and δ) chains.

Colored reverse-banding of human chromosomes with acridine orange following alkaline/formalin treatment: Densitometric validation and applications

SummaryA technique is described in detail for 1. differentially denaturing DNA along chromosome arms with sodium hydroxide containing formalin (NaOH-F) and 2. staining with acridine orange (AO). The NaOH-F/AO technique results in chromosomes with red, yellow, brown and green colored bands which, when photographed in black and white, appear to be the reverse of Q bands. Densitometry tracings of these patterns confirm them to be the reverse of Q bands with the exception of some centromeric regions and the secondary constrictions on chromosomes 1, 9 and 16.Studies on the age of slides indicate that spontaneous denaturation occurs at room temperature. Slides aged 2–3 weeks at room temperature give optimal results with the NaOH-F/AO technique. Trypsin treatment prior to NaOH-F/AO does not affect the resultant banding pattern.The NaOH-F/AO technique is useful because 1. it tends to stain the ends of chromosomes more clearly than does quinacrine — the utility of this feature is demonstrated by densitometry tracings of various chromosome rearrangements and 2. it can be used in sequence with other chromosome banding techniques on the same cell and so circumvents problems in the comparison of results obtained with different cells.ZusammenfassungEs wird eine Technik beschrieben, die folgende Schritte enthält:1.Differentielle Denaturierung von DNA an den Chromosomenarmen mit Na-Hydroxid, das Formalin enthält (NaOH-F). 2. Färbung mit Acridin-Orange. Die NaOH-F-Technik ergibt Chromosomen mit rot, gelb, braun und grün gefärbten Banden, die bei Schwarzweißphotographie als negative Q-Banden erscheinen. Das wird durch Densitometrie bestätigt — mit Ausnahme einiger Zentromerregionen und der Sekundärkonstruktionen auf den Chromosomen 1, 9, 16.Untersuchungen an gealterten Präparaten zeigen, daß spontane Denaturierung bei Zimmertemperatur auftritt. Präparate, die 2–3 Wochen bei Zimmertemperatur aufbewahrt wurden, geben mit der NaOH-F/AO-Technik optimale Resultate. Trypsin-Vorbehandlung beeinflußt das Bandmuster nicht.Die NaOH-F/AO-Technik hat die folgenden Vorteile: 1. Sie färbt die Chromosomenenden klarer als Quinacrin; die Nüzlichkeit dieser Eigenschaft wird durch densitometrische Bestimmungen verschiedener Chromosomen-Rearrangements bewiesen. 2. Sie kann zusammen mit anderen Bandentechniken an der gleichen Zelle verwertet werden; so umgeht man Schwierigkeiten, die bei Vergleich von Ergebnissen an verschiedenen Zelltypen auftreten.

Exclusion gene mapping utilizing patients with chromosome imbalance: The HL-A system as a prototype

Summary17 chromosomally unbalanced patients, their siblings and parents were tested for HL-A types and for up to 25 other polymorphic systems to determine whether there was gain or loss of an allele concurrent with the gain or loss of chromosome material. 5 patients had trisomy of part or all of a chromosome; 2 had trisomy of a segment and also deletion of chromosome material. All 7 were due to a familial translocation. The remaining patients had small deletions; 5 had ring chromosomes, 4 had rod deletions and 1 had missing chromosome material due to a heritable translocation. All cases were informative at the HL-A loci because of the high degree of polymorphism of the system whereas only some of the other systems were informative. None of the 17 patients showed unusual inheritance of HL-A or any other of the polymorphic systems examined. These results provide evidence excluding the HL-A and other loci from a number of possible locations in the human genome.

Autosomal rings and variable phenotypes

H u m a n cytogcnet ics has been i l l umina ted b y the recent p a p e r in this jou rna l of Kunze et al. (1972). They reviewed the pheno typ ic findings in cases of 18r and c o m p a r e d t h e m wi th the findings associa ted wi th 1 8 p and 18q. T h e y found t h a t al l the 18r cases showed pheno typ ic over lap wi th the 1 8 p a n d 1 8 q pa t ien t s . T h e y concluded t h a t the de l inea t ion of a sepa ra te 18r syndrome is no t just if ied. A n analys is we car r ied ou t (Vlietinck, 1970), using the same d a t a as K u n z e et al. plus d a t a de r ived f rom persona l observa t ions on two pa t i en t s wi th 18r and five pa t i en t s wi th 18p , also came to the conclusion t h a t no c learcut 18r synd rome could be del ineated . The bas ic ques t ion is : can consis tent clinical syndromes be de l inea ted wi th r ing chromosomes ? To answer th is ques t ion ful ly requires examina t ion of d a t a re la t ing to r ings de r ived f rom each of the 22 autosomes. I n the m a t t e r of r ing-18 chromosomes, the answer has now been suppl ied : no. Ring au tosomes are po ten t i a l l y t reacherous subjec ts for k a r y o t y p e p h e n o t y p e correlat ion, as has been suggested (Heeht , 1969). I t m igh t be p red ic t ed t h a t each p a t i e n t wi th a r ing der ived f rom a pa r t i cu la r au tosome migh t show a different pheno type . The possible sources of th is pheno typ ic v a r i a b i l i t y include the following :

9p trisomy identified by Giemsa-11

SummaryThe Giemsa-11 technique specifically stains the secondary constriction region of chromosome 9. We report cytologic evidence for 9p trisomy in a 4

Study of a patient with apparent monosomy 21 owing to translocation: 45,XX,21–,t(18q+)

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A prenatal diagnosis clinic: An initial report

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Re‐evaluation of the effect of spray adhesives on human chromosomes

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Mechanisms of Giemsa banding

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