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Biomedical subjects

G S Johnson

Publications and source records attributed to G S Johnson.

At least 19 recordsLinked to original sources
PubMed2006

The relationships among mitochondrial uncoupling protein 2 and 3 expression, mitochondrial deoxyribonucleic acid single nucleotide polymorphisms, and residual feed intake in Angus steers.

The objective of this study was to determine the relationships of uncoupling protein 2 and 3 expression, SNP of mitochondrial DNA, and residual feed intake (RFI) in Angus steers selected to have high or low RFI. Individual feed intake was measured via the GrowSafe feed intake system over a 3-mo period and used to calculate RFI, a measure of efficiency. Based on these calculations, 6 low- (average RFI = -1.57 kg) and 6 high- (average RFI = 1.66 kg) RFI steers were selected for further study. Blood was collected via jugular venipuncture 1 wk before slaughter for the isolation of mitochondrial DNA. The steers were then killed to collect LM for the measurement of uncoupling protein 2 and 3 mRNA and protein expression. Protein and mRNA expression of uncoupling protein 2 and 3 were determined by Western blotting and quantitative PCR, respectively. To determine SNP of mitochondrial DNA, total DNA was isolated from blood via standard phenol/chloroform extraction; fragments were amplified with PCR and sequenced with an automated nucleotide sequencer. Average daily gain and carcass composition were not different (P > 0.13) between the high- and low-RFI steers; however, ADFI by the high-RFI animals was 3.77 kg greater (P < 0.001) than the low-RFI animals. No difference (P > 0.55) was observed between the high- and low-RFI animals in their expression of uncoupling protein 2 or 3 mRNA or protein. On average 9.8 and 8.9 polymorphisms were found per mitochondrial genome for the low- and high-RFI steers, respectively. None of these polymorphisms were related to RFI. It seems that the expression of uncoupling protein 2 and 3 and mitochondrial DNA sequence are not related to RFI status.

Animal Feed↗
PubMed2004

Using genetic technologies for promoting canine health and temperament.

The entire canine genome is scheduled to be sequenced by researchers at the Whitehead Institute/MIH Center for Genome Research by the end of 2004. Thus, new genetic technologies are likely to be developed that can soon predict certain aspects of health and temperament in dogs. The C. familiaris is similar in size to that of humans and other mammals, with an estimated 2.8 billion base pairs. Although, the boxer was chosen as the first breed to sequence, it will have application for all dog breeds. Once the entire genome is sequenced, genetic markers for specific diseases and temperaments may be developed, which can guide breeders to make informed decisions concerning breeding management. Such a technology may be useful for guide and service dog organizations that have breeding colonies. It is important that the human-animal bond be preserved for as long as possible, both for pet owners and also for those disabled individuals who depend upon a dog for independence and mobility. Because genetic diseases may not manifest in carriers, and some genetic diseases do not manifest until after a dog is older and has already produced other animals with the same defect, genetic markers to identify some of the over 400 genetic diseases could be very useful in promoting canine health.

Animals↗
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

The processing and characterization of animal-derived bone to yield materials with biomedical applications. Part III: material and mechanical properties of fresh and processed bovine cancellous bone.

Conversion of bovine cancellous bone to a useful biomedical xenograft material involves several processing steps which include boiling, defatting and deproteination (i.e. bleaching). This study has shown how these processes can influence cancellous bone modulus and strength. It was found that prolonged boiling in water for six hours followed by NaOCl bleaching had a deleterious effect on the overall strength of the bovine bone. In contrast, bone samples subjected to only moderate boiling (1.5 hours) exhibited a 22% stiffness increase due mainly to the effects of drying. The same stiffened samples, when subjected to the bleaching procedure, retained some strength with only a small reduction in moduli values. It can be concluded that careful control of defatting and bleaching procedures on bovine bone is able to give a strong, albeit, brittle material with preservation of the original bone architecture. The bone xenograft materials are worthy of further investigation in in vivo clinical trials to assess their performance in contact with biological fluids.

Journal Article↗
PubMed2000

The processing and characterization of animal-derived bone to yield materials with biomedical applications. Part II: milled bone powders, reprecipitated hydroxyapatite and the potential uses of these materials.

Further studies on the processing and use of animal-bone-derived calcium phosphate materials in biomedical applications are presented. Bone powders sourced either from the direct crushing and milling of bovine, ovine and cervine bone or after being subjected to defatting and acid digestion/NaOH reprecipitation and sodium hypochlorite hydrogen peroxide treatment of animal bones were characterized using Fourier transform infra-red (FTIR) spectroscopy, 13C solid state magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, atomic absorption (AA) and inductively coupled plasma (ICP) spectrometric techniques. Bone powders were trialled for their potential use as a substrate for phosphine coupling and enzyme immobilization as well as a feedstock powder for plasma spraying on titanium metal substrates. Results indicated that enzyme immobilization by phosphine coupling could be successfully achieved on milled cervine bone with the immobilized enzyme retaining some activity. It was found that the presence of impurities normally carried down with the processing of the bone materials (viz., fat and collagen) played an important role in influencing the adsorbency and reactivity of the powders. Plasma spraying studies using reprecipitated bovine-derived powders produced highly adherent coatings on titanium metal, the composition of which was mostly hydroxyapatite (Ca10(PO4)6(OH)2) with low levels of alpha-tricalcium phosphate (alpha-Ca3(PO4)2) and tetracalcium phosphate (Ca4P2O9) also detected. In general, animal derived calcium phosphate materials constitute a potentially cheaper source of calcium phosphate materials for biomedical applications and make use of a largely under-utilized resource from abattoir wastes.

Journal Article↗
PubMed2000

The processing and characterization of animal-derived bone to yield materials with biomedical applications: part 1: modifiable porous implants from bovine condyle cancellous bone and characterization of bone materials as a function of processing.

A study on the development of a process to form materials suitable for biomedical xenograft implants from bovine cancellous bone is presented. Bone cubes cut from the condyle portion of bovine femurs sourced from abattoir waste were subjected to a defatting and subsequent deproteination procedure to produce shape-modifiable materials in which the biocompatible mineral calcium hydroxycarbonate apatite component was preserved in the original osseous architecture of the bovine bone. Optimum defatting was achieved by (1) thawing of the precut bone cubes in water, (2) pressure cooking at 15 psi in water, (3) soaking in 0.1 mol l(-1) NaOH followed by a thorough rinse under running water, (4) microwave heating of the bone cubes in water, (5) refluxing in methyl acetate and finally (6) removal of internal liquid from the cubes by shaking and then air drying. Subsequent deproteination of the defatted bone cubes was optimally achieved by (1) soaking in 5% sodium hypochlorite solution at ambient temperature using ultrasonication, (2) thorough rinsing of the cubes in water followed by drying. The final product is a defatted/deproteinated, bleached material that can be molded into various shapes for implant use in the body. The bone specimens were characterized by a suite of analytical techniques (i.e. infrared, 31P and 13C solid magic-angle spinning (MAS) nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopies, atomic absorption (AA) spectrometry, inductively coupled plasma (ICP) spectrometry, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM)) in order to follow compositional changes during the various stages of processing. In general, bovine condyles proved to be the best source of xenograft materials with condyles from other animal species (i.e. deer, sheep and ostrich) being too small to constitute a utilizable source of cancellous bone. This study shows how value can be added to a hitherto underutilized abattoir by-product by using simple processing techniques.

Journal Article↗
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↗