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Biomedical subjects

A Diamond

Publications and source records attributed to A Diamond.

At least 55 records · Page 3Linked to original sources
PubMed1986

Immunoglobulin heavy chain locus of the rat: striking homology to mouse antibody genes.

DNA encoding the rat diversity segment (D), joining segment (JH), and constant (C) region mu, gamma 2a, gamma 1, gamma 2b, epsilon and alpha of the Ig heavy chain has been isolated from a cosmid library. Restriction mapping allowed us to identify two gene clusters: D-JH-C mu and C gamma 1-C gamma 2b-C epsilon-C alpha in addition to a single C gamma 2a gene. Analysis of genomic DNA by Southern blotting permitted identification of the C gamma 2c gene and led to the proposal of the following gene order for the rat Ig heavy chain locus: D-JH-C mu-C delta-(C gamma 2c, C gamma 2a)-C gamma 1-C gamma 2b-C epsilon-C alpha. There is striking homology between the rat and mouse Ig heavy chain loci as regards gene order and distance between CH genes. Partial DNA sequencing confirms this homology and shows that exon sequences are more conserved than are intron sequences. One of the most conserved intron regions between rat and mouse is that spanning the Ig heavy chain enhancer (91% homology). However, the relationship between the different C gamma subclasses in rat differs from that in mouse. Comparison of the C gamma CH3 domains shows that the rat C gamma 2b gene is most homologous to mouse C gamma 2a/b, whereas the rat C gamma 1 and C gamma 2a genes, both very similar to each other, are most homologous to the mouse C gamma 1 gene.

Amino Acid Sequence↗
PubMed1985

The isolation and characterization of the Blym-1 transforming gene.

There are a number of similarities between chicken bursal lymphomas and human Burkitt's lymphomas. Both lymphomas are associated with viral infection, by LLV in bursal lymphomas and Epstein-Barr virus in Burkitt's lymphoma. Avian lymphoid leukosis virus integration is associated with enhanced c-myc expression, while the role EBV plays in tumorigenesis remains unclear. In Burkitt's lymphoma, however, c-myc activation does occur as a result of specific chromosomal translocations involving the human c-myc locus. Furthermore, the activated transforming genes detected by transfection of both bursal lymphoma and Burkitt's lymphoma DNAs are homologous members of the Blym family of genes. These similarities between chicken and human lymphomas provide evidence that viral involvement and oncogene activation are significant in tumor development and suggest they are involved in the multi-step progression to the neoplastic phenotype. The function of the Blym genes remains to be determined. Although the chicken and human Blym genes are only distantly related, they have maintained their homology to the amino-terminal regions of transferrins. This fact may reflect some functional constraint on the evolution of these genes. It is therefore possible that transforming genes such as Blym may function via a transferrin-related mechanism.

Animals↗
PubMed1985

Development of the ability to use recall to guide action, as indicated by infants' performance on AB.

25 infants were tested every 2 weeks on the AB Object Permanence Task devised by Piaget, from the age when they first reached for a hidden object until they were 12 months. The delay between hiding and retrieval necessary to produce the AB error increased continuously throughout this period at an average rate of 2 sec/month, from under 2 sec at 7 1/2 months to over 10 sec by 12 months. All children displayed the AB error repeatedly over the months of testing. Large between-children differences in delay needed for the AB error were found at each age. Girls tolerated longer delays than boys. The characteristic pattern to the AB error did not vary over age or sex. Range of delay producing the AB error in any child was small. Errors disappeared when delays were reduced by 2-3 sec, and reaching became random or severely perseverative when delays were increased 2-3 sec above the level producing AB error. AB provides an index of the ability to carry out an intention based on stored information despite a conflicting habitual tendency.

Child Development↗
PubMed1984

Nucleotide sequence of a human Blym transforming gene activated in a Burkitt's lymphoma.

The nucleotide sequence of a human Blym-1 transforming gene activated in a Burkitt's lymphoma cell line was determined. This sequence predicts a small protein of 58 amino acids that is 33 percent identical to the predicted product of chicken Blym-1, the activated transforming gene of chicken B cell lymphomas. Both the human and chicken Blym-1 genes exhibit significant identity to an amino-terminal region of transferrins.

Amino Acid Sequence↗
PubMed1984

Mapping of the human Blym-1 transforming gene activated in Burkitt lymphomas to chromosome 1.

Blym-1, a transforming gene detected by transfection of NIH 3T3 cells with DNA from Burkitt lymphomas, was mapped to the short arm of chromosome 1 (1p32) by chromosomal in situ hybridization. The Blym-1 gene was not physically linked to the cellular myc oncogene or to any of the immunoglobulin gene loci implicated in the characteristic chromosomal translocations in Burkitt lymphoma.

Base Sequence↗
PubMed1982

Opal suppressor serine tRNAs from bovine liver form phosphoseryl-tRNA.

An unusual minor species of bovine liver serine tRNA has previously been isolated, sequenced, and found to suppress the UGA termination codon in protein synthesis in vitro [Diamond, A., Dudock, B. & Hatfield, D. (1981) Cell 25, 497-506]. We have now found that this tRNA can be a substrate in a specific phosphorylation reaction in which phosphoseryl-tRNA is formed. Moreover, bovine liver contains a second UGA suppressor serine tRNA (tRNASerNCA; N is a modified nucleoside) which also forms phosphoseryl-tRNA. The nucleotide sequence and coding properties of tRNASerNCA are presented.

Animals↗
PubMed1981

Structure and properties of a bovine liver UGA suppressor serine tRNA with a tryptophan anticodon.

A bovine liver serine tRNA with a variety of unusual features has been sequenced and characterized. This tRNA is aminoacylated with serine, although it has a tryptophan anticodon CmCA. In ribosome binding assays, this tRNA (tRNASERCmCA) binds to the termination codon UGA and shows little or no binding in response to a variety of other codons including those for tryptophan and serine. The unusual codon recognition properties of this molecule were confirmed in an in vitro assay where this tRNA suppressed UGA termination. This is the first naturally occurring eucaryotic suppressor tRNA to be so characterized. Other unusual features, possibly related to the ability of this tRNA to read UGA, are the presence of two extra nucleotides, compared to all other tRNAs, between the universal residues U at position 8 and A at position 14 and the presence of an extra unpaired nucleotide within the double-stranded loop IV stem. This tRNA is also the largest eucaryotic tRNA sequenced to date (90 nucleotides). Despite its size, however, it contains only six modified residues, tRNASerCmCA shows extremely low homology to other mammalian serine (47-52% homology) or tryptophan (49% homology) tRNAs.

Animals↗
PubMed1977

Renal sinus angiomyolipoma.

The first case of an angiomyolipoma limited to the renal sinus is presented. The radiographic findings were a relatively lucent mass within the renal sinus (extrarenal); neovascularity that did not respond to epinephrine; lack of arteriovenous shunting; a "whorled" venous pattern; and displacement and compression of the renal vein without evidence of invasion. Infusion nephrotomography and renal venography were crucial in the localization and preoperative suggestion of this benign renal sinus lesion. The renal sinus angiomyolipoma was removed by blunt dissection and the kidney preserved.

Diagnosis, Differential↗
PubMed1976

Intrahepatic rupture secondary to duct exploration demonstrated by cholangiography.

Seven cases of iatrogenic rupture of the intrahepatic bile ducts were demonstrated on T-tube and/or operative cholangiography. This brings the total of documented case reports to 17. All patients had hepatic duct exploration with either the Fogarty balloon catheter and/or the biliary spoon and/or the biliary forceps and/or Bakes dilators. These extravasations usually occur from the right hepatic duct. The recognition of this entity is important because potentially serious complications may occur. Most of the previous cases of intrahepatic extravasation ascribed to excessive pressures of injection were probably surgically induced.

Adult↗
PubMed1975

Venographic demonstration of a varicocele in a boy.

A case is presented to illustrate the evaluation of varicocele in a boy by a combined technique of spermatic venography and excretory urography. The pertinent technical, anatomical and clinical considerations are discussed. Varicocele is a clinical diagnosis. If the diagnosis is suspected or the clinical presentation is unusual, then a combined technique of spermatic venography and excretory urography may be of value.

Child↗