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G S Johnson

Publications and source records attributed to G S Johnson.

At least 19 recordsLinked to original sources
PubMed2001

Meiotic linkage mapping of 52 genes onto the canine map does not identify significant levels of microrearrangement.

In an effort to extend our understanding of the evolutionary relationship between the canine and human genomes, we have developed and positioned 52 new gene-associated polymorphic markers on the canine meiotic linkage map. Canine-specific PCR primers were developed from the consensus of published sequences of several mammalian genomes and were designed to span intronic regions, thus optimizing the probability that a polymorphic site was included. The resulting markers were analyzed on a panel of three-generation canine reference families and the data were incorporated into the current meiotic linkage map. The data were compared with those generated by three chromosome paint studies in an effort to understand the distribution and frequency of microrearrangements within the canine genome. Forty-eight of 52 genes map to a chromosomal region predicted to contain genes from the corresponding region of the human genome according to all published reciprocal chromosome paint studies. Meiotic linkage mapping data for three genes can be used to resolve discrepancies between the published reciprocal chromosome paint studies, and for an additional two genes, meiotic mapping data allow evolutionary breakpoints to be more precisely defined. We conclude that microrearrangements of evolutionarily conserved segments between the canine and human genomes are rare, occurring for less than 0.5% of gene data reported to date. In addition, we have found that the placement of genes on the meiotic linkage map is a useful mechanism for resolving discrepancies between existing data sets.

Animals↗
PubMed2001

Effect of rejuvenation and frozen storage on 42-day-old AS-1 RBCs.

BACKGROUND: The FDA has approved a 42-day storage period for RBCs stored in ADSOL (AS-1). This study was undertaken to provide data for the FDA about the feasibility of salvaging AS-1 RBCs at the end of their storage period by rejuvenation and freezing. STUDY DESIGN AND METHOD: The investigation, consisting of a study (n = 10) and control (n = 6) arm, was carried out in two centers. In both centers, eight healthy volunteers donated a unit (450 mL) of whole blood. The RBC concentrates were stored at 4 degrees C in AS-1 for 42 days. The study units were rejuvenated, whereas the control units were not. All units were stored frozen at -80 degrees C, then deglycerolized and kept for an additional 24 hours at 4 degrees C. RESULTS: After the 42-day storage period, ATP had declined to 62 percent of the original value, 2,3 DPG was zero, and MCV was significantly larger than that of fresh RBCS: Following rejuvenation and deglycerolization, the mean ATP level was 141 percent, the mean 2,3 DPG level was 109 percent, and the MCV was normal. The freeze-thaw-wash recovery of the rejuvenated and nonrejuvenated RBCs was similar, 88.4 and 84.0 percent, respectively. There was no difference in hypoxanthine, inosine, and uric acid levels in the rejuvenated and nonrejuvenated units, which indicated that the chemicals in the rejuvenation solution and their by-products had been removed during processing. In both centers, the mean 24-hour survival of rejuvenated, deglycerolized RBCs exceeded 75 percent, whereas that of nonrejuvenated RBCs did not. The long-term survival rates of viable study and control RBCs were similar. CONCLUSION: Forty-two-day-old AS-1 RBCs that have been rejuvenated and then frozen have more than 75 percent viability and normal oxygen delivery function. Rejuvenation of RBCs does not introduce additional safety hazards to blood transfusion.

Blood Preservation↗
PubMed2001

Mouse gene knockout models for the CLN2 and CLN3 forms of ceroid lipofuscinosis.

The childhood neuronal ceroid-lipofuscinoses (NCLs) are autosomal-recessively inherited neurodegenerative disorders that result in severe cognitive decline and premature death. The genetic bases for a number of different forms of NCL, including those designated CLN2 and CLN3, have now been determined. However, the mechanisms by which the gene defects cause the disease pathology are not known and no effective treatments for these disorders have been developed. To provide tools for studying the mechanisms underlying the disease pathologies and for screening potential therapeutic interventions, work is under way to develop mouse models for the CLN2 and CLN3 disorders. Targeted gene replacement was used to generate mice in which the murine orthologue of the CLN3 gene has been knocked out. Mice that are homozygous for the Cln3 knockout allele develop a number of pathological features similar to those that occur in the human disorder. Among these are accumulation of autofluorescent lysosomal storage bodies, behavioural abnormalities, retinal degeneration, and premature death. On a mixed strain genetic background, the appearance of these symptoms was quite variable, suggesting that other genes can modify the effects of CLN3 mutations. Work to develop a similar mouse gene knockout model for the CLN2 disorder is well under way. Chimaeric mice have been developed with cells that carry an induced mutation in the mouse orthologue of the CLN2 gene that would prevent synthesis of a functional CLN2 protein in mice that are homozygous for the mutation. Mice will be developed that are homozygous for this mutation, and these animals will be evaluated for the development of pathologies similar to those that occur in the human disorder.

Aminopeptidases↗
PubMed2001

West Nile virus: a case study in how NY State Health Information infrastructure facilitates preparation and response to disease outbreaks.

New York's (NY) Health Information Network (HIN) provided timely access to West Nile Virus (WNV) data during the initial outbreak in the late Summer 1999. In December 1999, NY developed a plan to deal with WNV in 2000 that required an integrated surveillance system for humans, birds, mammals, and mosquitoes. The HIN infrastructure allowed NY to deploy this system statewide in three months. Local health departments throughout NY used the system to report, track, and retrieve surveillance data as WNV spread throughout NY in 2000. The HIN infrastructure includes partnerships, training/support, technical capacity and architecture similar to NEDSS as proposed by the US CDC.

Animals↗
PubMed2000

Histopathologic and immunocytochemical analysis of the retina and ocular tissues in Batten disease.

PURPOSE: To describe the pathophysiologic features of retinal degeneration in Batten disease (juvenile neuronal ceroid lipofuscinosis [JNCL]) caused by mutations in the CLN3 gene. STUDY DESIGN: Comparative human tissue study. MATERIALS: The retina and other ocular tissues of a 22-year-old man with JNCL were compared with the same tissues of a healthy 30-year-old man. DNA from whole blood and RNA from retina were used for genotype analysis. METHODS: The retinas, corneas, conjunctiva, and ciliary body were processed for histopathologic and immunofluorescence analysis. Genomic DNA was subjected to polymerase chain reaction (PCR) and nucleotide sequence analyses. Reverse transcriptase/PCR and sequence analysis were performed on retinal RNA. RESULTS: The JNCL donor was heterozygous for a approximately 1 kb deletion in CLN3, as found in most JNCL patients. The other allele had a single base pair deletion in exon 6 that resulted in a frame shift. Gross pathology of the JNCL retina resembled that in retinitis pigmentosa, including deposits of bone spicule pigment. Histopathologic studies revealed loss of neurons from all retinal layers. Immunofluorescence labeling with antibodies to rhodopsin, recoverin, and cone opsin demonstrated degenerate rods and cones with short outer segments in the far periphery. Autofluorescent lipopigment granules were prominent in ganglion cells and some cells of the inner nuclear layer, but not in the photoreceptors. The retinal pigment epithelium (RPE) had fewer lipofuscin granules than the control specimen. Increased numbers of lipofuscin granules were found in the epithelia of the ciliary body and conjunctiva, but not in the cornea of the JNCL eye. CONCLUSIONS: Immunofluorescence studies revealed degenerate rods and cones in the far periphery. Lipofuscin granules were decreased in the RPE, consistent with loss of photoreceptor outer segments. The novel finding that degenerate photoreceptors did not contain autofluorescent inclusions suggests that granule accumulation may not precede photoreceptor degeneration in JNCL. The presence of normal photoreceptor proteins in the degenerate rods and cones suggests that these cells may be capable of functional regeneration if a therapy for Batten disease is developed.

Adult↗
PubMed2000

Isolation and characterization of the normal canine beta-galactosidase gene and its mutation in a dog model of GM1-gangliosidosis.

The acid beta-galactosidase cDNA of Portuguese Water dogs was isolated and sequenced. The entire coding region of the gene consists of 2004 nucleotides encoding a protein of 668 amino acids. Its encoding sequence indicates approximately 86.5% identity at the nucleotide level and about 81% identity at the amino acid level with the encoding region of the human acid beta-galactosidase gene. The deduced amino acid sequence contains a 24-amino-acid putative signal sequence, six possible glycosylation sites, and seven cysteine residues. A homozygous recessive mutation, causing canine GM1-gangliosidosis, was identified at nucleotide G200-->A in exon 2 resulting in an Arg60-->His (mutation R60H) amino acid substitution. The mutation creates a new restriction enzyme site for Pml1. Genotyping 115 dog samples for this acid beta-galactosidase gene alteration readily distinguished affected homozygous recessives (n=5), heterozygous carriers (n=50) and normal homozygotes (n=60). DNA mutation analysis provided a method more specific than enzyme assay of beta-galactosidase for determination of carriers.

Amino Acid Sequence↗
PubMed2000

Decreased growth in angus steers with a short TG-microsatellite allele in the P1 promoter of the growth hormone receptor gene.

A polymorphic TG-repeat microsatellite is located 90 base pairs upstream from a major transcription start site in the bovine growth hormone receptor gene. A shorter allele with 11 consecutive TG is common in Bos indicus cattle, whereas longer 16- to 20-TG-repeat alleles predominate in Bos taurus breeds. The purpose of this study was to compare growth and carcass traits between Angus steers that had two of the longer growth hormone receptor alleles with their half-siblings that had one short allele and one of the longer alleles. We genotyped 64 Angus sires with respect to the poly-TG microsatellite and identified six bulls that were heterozygous in that they had one short 11-TG allele and one of the longer alleles. We then grouped 125 steer progeny of these six heterozygous bulls according to their genotypes: only the longer 16- to 20-TG-repeat alleles were found in 73 steer progeny (long/long homozygotes), whereas a short 11-TG allele was paired with one of the longer alleles in 52 progeny (short/long heterozygotes). Contrasts for the long/long homozygotes vs the short/long heterozygotes were significant for weaning weight (17 +/- 4 kg; P < .001) and carcass weight (14 +/- 5 kg; P < .01). Approaching significance (P = .03) was the contrast for USDA marbling score (-.3 +/- .2). No significant differences (P > .05) were detected for contrasts in birth weight (.3 +/- .6 kg), longissimus muscle area (-.2 +/- 1 cm2), or carcass fat depth (-.01 +/- .07 cm). This polymorphism has potential for use in DNA marker-assisted selection programs.

Alleles↗
PubMed1999

A mouse gene knockout model for juvenile ceroid-lipofuscinosis (Batten disease).

The human hereditary ceroid-lipofuscinoses are a group of autosomal recessively inherited diseases characterized by massive accumulations of autofluorescent lysosomal storage bodies in the cells of many tissues and by neuronal degeneration throughout the central nervous system. There are a number of clinically and genetically distinct forms of ceroid-lipofuscinosis, the most common of which is the juvenile type, also known as Batten disease and CLN3. To study the mechanisms that lead to pathology in CLN3 and to evaluate potential therapies, a mouse model has been generated by targeted disruption of the mouse ortholog of the CLN3 gene (Cln3). As in affected humans, mice homozygous for the disrupted Cln3 allele show accumulation of autofluorescent storage material in neurons and other cell types. The storage material consists of membrane-bounded intracellular inclusions with ultrastructural features typical of the ceroid-lipofuscinoses. The accumulation of this storage material validates the Cln3 knockout mice as a model for the human disorder.

Animals↗
PubMed1999

A novel and de novo spontaneous point mutation (Glu271STOP) of the antithrombin gene results in a type I deficiency and thrombophilia.

We describe a novel, de novo point mutation in one antithrombin (AT) allele resulting in type I AT deficiency and thrombophilia. Low plasma AT activity as well as low plasma AT antigen were documented in the propositus, but not in the parents, or in a male sibling. AT gene analysis by sequencing polymerase chain reaction-amplified genomic DNA from exon 5 of the propositus revealed a novel point mutation, GAG-->TAG at codon 271, resulting in a stop codon (Glu271STOP). This mutation was not demonstrable in the other members of his immediate family. DNA marker polymorphism analysis indicated the expected parentage. Based on allele frequency data for Caucasians in the United States the cumulative paternity index, or CPI, for the propositus and his father is 219,077. This corresponds to a probability of paternity of 99.9995% based on a prior probability of 50%. Included in this analysis is a linkage analysis of a trinucleotide repeat in intron 5 of the AT gene of the various family members, which also confirmed maternity and paternity. These studies provide documentation of the first spontaneous mutation of an AT gene in a thrombophilic individual, resulting in a type I AT deficiency.

Adolescent↗
PubMed1999

Characterization and chromosomal mapping of a mouse ortholog of the late-infantile ceroid-lipofuscinosis gene CLN2.

Late-infantile ceroid-lipofuscinosis (CLN2) is an autosomal recessively inherited, neurodegenerative disease in humans. The CLN2 locus has been mapped to Chromosome (Chr) 11p15, and its sequence and genomic organization have recently been reported. In the present study, the cDNA sequence, exon/intron organization, and chromosomal localization of a mouse ortholog of the CLN2 gene are described. The mouse cDNA contains an open reading frame that predicts a protein product of 562 amino acids. The mouse and human coding regions are 86% and 88% identical at the nucleic acid and amino acid levels, respectively. One less codon appears in the mouse cDNA when compared with the human ortholog. The mouse gene (Cln2) spans more than 6 kb and consists of 13 exons separated by introns ranging in size from 111 to 1259 bp. Length polymorphism in an (AC)(n) microsatellite in intron 3 of the mouse Cln2 gene was used to perform segregation analysis with The Jackson Laboratory DNA Panel Mapping Resource. On the basis of this analysis, the Cln2 gene was localized to a region of mouse Chr 7 that corresponds to human Chr 11p15. Characterization of the mouse Cln2 gene will facilitate generation of a mouse model for late-infantile ceroid-lipofuscinosis by gene targeting and identification of functionally important regions of the Cln2 protein.

Amino Acid Sequence↗
PubMed1998

Coding sequence and exon/intron organization of the canine CLN3 (Batten disease) gene and its exclusion as the locus for ceroid-lipofuscinosis in English setter dogs.

Hereditary ceroid-lipofuscinosis in English setters has been proposed to be the canine equivalent of human juvenile ceroid-lipofuscinosis, which results from defects in the CLN3 gene. Analyses were performed to determine whether the disease in English setters is also the consequence of a CLN3 gene mutation. Canine CLN3 cDNA was found to contain a 1,314-bp open reading frame predicting a derived amino acid sequence which is 89%, 85%, and 84% identical to the predicted amino acid sequences for the human, mouse, and rabbit CLN3 proteins, respectively. The canine gene has sixteen exons. No differences were detected when cDNA nucleotide sequences from an English setter with ceroid-lipofuscinosis and from a normal dog were compared. Moreover, alleles of the canine CLN3 gene distinguished by an intragenic marker segregated independently from the disease in an English setter family, eliminating CLN3 as the locus for the canine disease. A ceroid-lipofuscinosis-affected Tibetan terrier was homozygous for a Gly70Glu CLN3 variant; however, this allele is common in dog breeds considered free of ceroid-lipofuscinosis.

Amino Acid Sequence↗
PubMed1998

Expression and location of pro-apoptotic Bcl-2 family protein BAD in normal human tissues and tumor cell lines.

The BAD protein is a pro-apoptotic member of the Bcl-2 family whose ability to heterodimerize with survival proteins such as Bcl-X(L) and to promote cell death is inhibited by phosphorylation. Monoclonal antibodies were generated against the human BAD protein and used to evaluate its expression by immunoblotting and immunohistochemistry in normal human tissues and by immunoblot analysis of the National Cancer Institute anti-cancer drug screening panel of 60 human tumor cell lines. BAD protein was detectable by immunoblotting in many normal tissues, with testis, breast, colon, and spleen being among those with the highest steady-state levels. Immunostaining of tissues revealed many examples of cell-type-specific expression of BAD, suggesting dynamic regulation of BAD protein levels in vivo. In many types of normal cells, BAD immunoreactivity was associated with cytosolic organelles resembling mitochondria, suggesting that BAD is often heterodimerized with other Bcl-2 family proteins in vivo. The relative levels of BAD protein varied widely among established human tumor cell lines, with colon, lung, and melanomas generally having the highest expression. As a group, hematopoietic and lymphoid lines contained the least BAD protein. The BAD protein derived from 11 of 41 tumor lines that expressed this pro-apoptotic protein migrated in gels as a clear doublet, consistent with the presence of hyperphosphorylated BAD protein. Taken together, these findings define for the first time the normal cell-type-specific patterns of expression and intracellular locations of the BAD protein in vivo and provide insights into the regulation of this pro-apoptotic Bcl-2 family protein in human tumors.

Antibodies, Monoclonal↗
PubMed1998

Risk of cancer mortality among the Longitudinal Study of Astronaut Health (LSAH) participants.

BACKGROUND: The potential for occupational radiation exposures in the U.S. Space Program makes cancer risk a major health concern. METHODS: The NASA Medical Operations Branch and KRUG Life Sciences Epidemiology Section at the Johnson Space Center (JSC) investigated the rate of cancer mortality among the astronauts and the comparison participants of the Longitudinal Study of Astronaut Health (LSAH). Medical records are maintained by the JSC Flight Medicine Clinic, JSC Occupational Medicine Clinic, and LSAH. Cause of death data from death certificates were reviewed for cancer mortality. These data were compared with cancer mortality data for the general population residing in the Texas Gulf Coast area. RESULTS: The astronauts had a higher age-specific risk of cancer mortality than the comparison group (SMR = 345; 95% CI = 69.5-756.2), but the difference did not reach statistical significance. Both the astronauts and the comparison group had lower age-specific rates than the general population (SMR = 47, 95% CI = 9.6-105.1; SMR = 17, 95% CI = 3.5-37.9, respectively).

Adult↗