The 2,4-dinitrophenyl group for protection of hydroxyl function of tyrosine during solid-phase peptide synthesis

The facile thiolytic cleavage of the O-2,4-dinitrophenyl (Dnp) tyrosine bond was applied to the solid-phase synthesis of the 22-amino acid residue peptide H-Asp-Ala-Val-Tyr -Thr-Gly-Leu-Asn-Thr-Arg-Asn-Gln-Glu-Thr-Tyr -Glu-Thr-Leu-Lys-His-Glu-Lys-OH, corresponding to positions 62-83 in the chain of the type 1 receptor for Fc_ε, domains expressed on the rat mucosal-type mast cells (line RBL-2H3). A method for the spectrophotometric determination of insoluble O-Dnp as well as of unprotected phenolic moieties of tyrosine was developed. It is based on monitoring S-Dnp-2-mercaptoethanol, produced upon O-Dnp thiolysis by 2-mercaptoethanol. © Munksgaard 1995. Dedicated to the memory of Dr. Susumu Funakoshi, a dear friend and a leader in peptide chemistry.     

Working alongside the general practitioner: a child psychiatric clinic in the general practice setting

A monthly child psychiatric clinic was established in a primary health care centre in order to offer a more accessible service to patients, and to improve liaison with primary health care professionals. Compared with the base child guidance unit, at the health centre there was a better first attendance rate, a much higher proportion of referrals from health professionals especially general practitioners, and an increased proportion of younger children referred. If further follow-up was necessary at the child guidance unit the attendance rate was very good. The service provided, although not reducing the need for a main multidisciplinary base, offered an acceptable and accessible opportunity for children with psychological problems to be assessed and treated, and for the referring professionals to have easy communication with the child psychiatrist.     

Dynamic mutation loci: allele distributions in different populations

To assess the relative contributions of trans -acting factors (replication and repair functions) and cis -acting elements (repeat and flanking DNA composition) to the mechanism of trinucleotide repeat sequence mutation we have analysed the distribution of copy number polymorphisms at 12 loci associated with dynamic mutations in 15 populations of different ethnic origins. Genome wide instability of repeats in a particular population would be evidence of trans -acting factor instigation of the mutation process, whereas instability at a particular locus (perhaps even in several populations) would be evidence that the composition of the particular locus was the most significant factor contributing to mutation. The FRA16A locus is highly polymorphic in only the European population. Some other loci exhibit distinct distributions of alleles between different populations. Therefore sequences in the vicinity of the repeat - the cis component of a particular locus - appear(s) to be more important in the mutation mechanism than sporadic genome-wide instability induced by trans -acting factors such as the DNA mismatch repair enzymes.     

On the Retention of the Fetus as a Homograft

ABSTRACT: The conceptus is tolerated in spite of the antigenic dissimilarities between mother and fetus. A new hypothesis to account for this phenomenon is put forward. It is suggested that the vessels within the trophoblastic villi—analogous to the vessels of malignant tumors—are permeable to humoral substances but impervious to cellular elements. This property allows for the exchange of nutrients and metabolites but, at the same time, precludes the passage of leukocytes. The block to diapedesis is believed to be due to the deposition of an occlusive layer of alpha₂-macroglobulin on vascular endothelium. The source of this protide is the fetal liver. In the absence of diapedesis there is no homograft reaction within the placenta. The “graft” is tolerated.     

Ethnicity and myotonic dystrophy: a possible explanation for its absence in sub-Saharan Africa

The CTG trinucleotide repeat, in the myotonic dystrophy (DM) myotonin protein kinase gene, was studied by PCR analysis in a total of 246 unrelated South African Bantu-speaking Negroids, 116 San and 27 Pygmies. The size and distribution of the CTG repeat were determined and showed that the alleles ranged in length from 5 to 22 repeats. The most common CTG repeat is 5 (25% of chromosomes) in the South African Negroids but 11 (27 % of chromosomes) in the San population and 12 (22% of chromosomes) in the Pygmies. The southern African Bantu-speaking Negroids and San were found to have significantly fewer large repeat length alleles than do Caucasoid and Japanese populations. Since DM has not been observed in southern African Negroids, it is possible that the occurrence of fewer large CTG repeats in the normal range may, in part, explain this absence. It seems likely, that the rare DM mutation event postulated to have occurred on a specific chromosomal haplotype, occurred after the migration of humans from Africa.