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T Barnett

Publications and source records attributed to T Barnett.

48 records · Page 3Linked to original sources
PubMed1988

Carcinoembryonic antigen family: characterization of cDNAs coding for NCA and CEA and suggestion of nonrandom sequence variation in their conserved loop-domains.

We have isolated cDNAs for carcinoembryonic antigen (CEA) and for a normal cross-reacting antigen (NCA) and report here their nucleotide and derived amino acid sequences. Our data show that both the CEA and NCA polypeptides are organized into extracellular domains, some with cysteine-linked loops, that share extensive sequence homology (approximately 78% overall) with each other and appear similar to immunoglobulin superfamily members. A major difference between the two apoproteins is the presence of a single loop-domain in NCA compared to three tandemly repeated loop-domains in CEA. Sequence comparisons between the extracellular domains of CEA and NCA show that the N-terminal and adjacent loop domains of each apoprotein have high homology (85-90%) to each other, while comparison of loop-domain regions reveals a possible nonrandom distribution of base changes and altered amino acids near certain cysteine residues that are inferred to be involved in forming disulfide loops. Both apoproteins show high identity in their hydrophobic C-termini that are reminiscent of the type of transmembrane tails seen in proteins that potentiate signal transduction. These findings, coupled with distinct expression profiles of CEA and NCA mRNAs, suggest that these apoproteins may function as unique cell-surface molecules mediating cell-specific interactions in normal and neoplastic cells.

Amino Acid Sequence↗
PubMed1981

Nontranscribed spacers in Drosophila ribosomal DNA.

Ribosomal DNA nontranscribed spacers in Drosophila virilis DNA have been examined in some detail by restriction site analysis of cloned segments of rDNA, nucleic acid hybridizations involving unfractionated rDNA, and base composition estimates. The overall G + C content of the spacer is 27--28%; this compares with 39% for rDNA as a whole, 40% for main band DNA, and 26% for the D. virilis satellites. Much of the spacer is comprised of 0.25 kb repeats revealed by digestion with Msp I, Fnu DII or Rsd I, which terminate very near the beginning of the template for the ribosomal RNA precursor. The spacers are heterogeneous in length among rDNA repeats, and this is largely accounted for by variation among rDNA units in the number of 0.25 kb elements per spacer. Despite its high A + T content and the repetitive nature of much of the spacer, and the proximity of rDNA and heterochromatin in Drosophila, pyrimidine tract analysis gave no indication of relatedness between the spacer and satellite DNA sequences. Species of Drosophila closely related to D. virilis have rDNA spacers that are homologous with those in D. virilis to the extent that hybridization of a cloned spacer segment of D. virilis rDNA to various DNA is comparable with hybridization to homologous DNA, and distributions of restriction enzyme cleavage sites are very similar (but not identical) among spacers of the various species. There is spacer length heterogeneity in the rDNA of all species, and each species has a unique major rDNA spacer length. Judging from Southern blot hybridization, D. hydei rDNA spacers have 20--30% sequence homology with D. virilis rDNA spacers, and a repetitive component is similarly sensitive to Msp I and Fnu DII digestion. D. melanogaster rDNA spacers have little or no homology with counterparts in D. virilis rDNA, despite a similar content of 0.25 kb repetitive elements. In contrast, sequences in rDNA that encode 18S and 28S ribosomal RNA have been highly conserved during the divergence of Drosophila species; this is inferred from interspecific hybridizations involving ribosomal RNA and a comparison of distributions of restriction enzyme cleavage sites in rDNA.

Animals↗
PubMed1980

The isolation and characterization of Drosophila yolk protein genes.

We have isolated recombinant DNA clones that contain the genomic sequences coding for the three most abundant proteins in Drosophila eggs, the yolk proteins (YP1, YP2 and YP3). The identity of these cloned genes was established by a two-step procedure. We used the genes to isolate complementary mRNA from total Drosophila RNA; we than showed the in vitro translation products of the isolated mRNAs to be the yolk proteins by comparing their protease digestion products to those of yolk proteins isolated from eggs. An examination of these isolated genes and of their DNA complements in the Drosophila genome showed that each of the three coordinately expressed yolk proteins is encoded by a different single-copy gene. Three genes were cloned; each has a different pattern of restriction endonuclease sites and each appears to be homologous to a different yolk protein mRNA. Southern transfer blots demonstrated that there is only one copy of each gene in the Drosophila genome. Our structural studies have shown that these three genes are not adjacent. In situ hybridization to polytene chromosomes demonstrated, in fact, that the YP3 gene is approximately 1000 kb from the closely spaced YP1 and YP2 genes. Thus, if the coordinate synthesis of the yolk proteins is due to transcriptional control, there must be coordinate control of initiation at two distant sites.

Animals↗
PubMed1979

A 9.6 kb intervening sequence in D. virilis rDNA, and sequence homology in rDNA interruptions of diverse species of Drosophila and other diptera.

A large proportion of the 28S ribosomal RNA genes in Drosophila virilis are interrupted by a DNA sequence 9.6 kilobase pairs long. As regards both its presence and its position in the 28S gene (about two thirds of the way in), the D. virilis rDNA intervening sequence is similar to that found in D. melanogaster rDNA, but lengths differ markedly between the two species. Degrees of nucleotide sequence homology have been detected bewteen rDNA interruptions of the two species. This homology extends to putative rDNA intervening sequences in diverse higher diptera (other Drosophila species, the house fly and the flesh fly), but hybridization of cloned D. melanogaster and D. virilis rDNA interruption segments to DNA of several lower diptera has been negative. As is the case with melanogaster rDNA interruptions, segments of the virilis rDNA intervening sequence hybridize with non-rDNA components of the virilis genome, and interspecific homology may involve these non-rDNA sequences as well as rDNA interruptions. There is, however, evidence from buoyant density fractionation of DNA that the distributions of interruption-related sequences are distinct in D. melanogaster and D. virilis genomes. Moreover, thermal denaturation studies have indicated differing extents of homology between hybridizable sequences in D. virilis DNA and different segments of the D. melanogaster rDNA intervening sequence. We infer from our studies that rDNA intervening sequences are prevalent among higher diptera; that in the course of the evolution of these organisms, elements of the intervening sequences have been moderately to highly conserved; and that this conservation extends in at least two distantly related species of Drosophila to similar sequences found elsewhere in the genomes.

Animals↗
PubMed1978

The logical analysis of the electroenterogram.

Simple--and inexpensive--logic circuitry is described which will discriminate three types of spike activity in the canine electroenterogram. Used during high-speed replay of tape-recorded myoelectric activity, it provides a numerical analysis of the duration and spike content of the three types of activity, without the need for sophisticated (and costly) computer analysis. The ability of the analyzer to detect types of activity is illustrated by the analysis of the effects of a peptide hormone infusion on the canine electroenterogram. The device might also serve as the prototype for other applications in which simple digital logic could be used to detect different patterns in continous analog signals.

Animals↗
PubMed1978

Brush biopsy of pyelocalyceal lesions via a percutaneous translumbar approach.

Percutaneous translumbar selective brush biopsy of pyelocalyceal and ureteric lesions is simple, permits ready access to all calyces as well as the ureter and renal pelvis, and facilitates multiple biopsies from different sites. The ability to retrieve tissue fragments from between the bristles allows histological diagnosis in addition to a Papanicolaou smear. Selective washings can be obtained for bacteriologic diagnosis; in many instances, cultures taken directly from the lesion proved to be different from samples taken from the bladder urine or renal pelvis. This method can be expanded to serve a means of establishing a temporary percutaneous nephropyelostomy.

Adult↗
PubMed1977

Automated high-speed analysis of gastrointestinal myoelectric activity.

The value of myoelectric recording in the gastrointestinal tract has been limited by the difficulty of analyzing the prolonged recordings which are required to demonstrate integrated physiological activity. This problem has been solved by the use of a tape recording system with accelerated replay, originally developed for cardiac monitoring. Rapid replay not only reduces the time required for data retrieval but also increases the frequency of the recorded signals to allow electronic separation of fast and slow wave activity for on-line conversion into digital pulses suitable for computer analysis. The technique is illustrated by the analysis of an imperfect prolonged multichannel recording of cannine gastrointestinal myoelectric activity, demonstrating some of the possibilities for data analysis and error detection inherent in the system.

Animals↗
PubMedDate not supplied

La Commande du Coeur ("Shop for Your Heart"): a point-of-choice nutrition education campaign in a low-income urban neighborhood.

This research suggests that point-of-choice campaigns can be implemented in low-income communities, although store personnel began to view campaign materials and activities as a nuisance after 2 months, and their enthusiasm and commitment decreased. Employee interest might have been more sustainable if the campaign had been shorter or if it had been implemented 1 or 2 weeks at a time rather than being continually present in the store. This approach would necessitate easily removable displays and materials. Items such as the kiosk were too cumbersome for easy setup and removal. Despite widespread advertisement and 4 months in the community, awareness of the campaign was moderate and use was low. Not surprisingly, awareness and use were higher among women, older persons, and persons who lived in St-Henri, possibly because they do the shopping or have the time and interest to notice promotional messages. Awareness and use of specific campaign components appeared to be higher for easily available, highly visible materials and activities that required little or no effort by consumers. Others have suggested that consumer effort required to recognize, view, read, and internalize point-of-choice messages is important and have recommended methods such as videocassettes of nutrition messages or brand-specific shelf labels that reduce customer effort to absorb information. Both the intervention agent and retailers reported that the cholesterol screening events were very popular and that they should have been offered more frequently. Although these events are relatively complex and costly, this response suggests that they are an appropriate and effective way to increase awareness and heighten interest. By contrast, almost no interest was shown in supermarket tours. Although our publicity might have been ineffective, it is more likely that this kind of activity did not interest the target group, possibly because of lack of time or low perceived need or usefulness.

Adolescent↗