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J F Morrow

Publications and source records attributed to J F Morrow.

At least 19 recordsLinked to original sources
PubMed1997

Quantification of the paternal allele bias for new germline mutations in the retinoblastoma gene.

New germline mutations in the human retinoblastoma gene are known to arise preferentially on paternally derived chromosomes, but the magnitude of that bias has not been measured. We evaluated 49 cases with a new germline mutation and found that in 40 cases (82%) the mutation arose on the paternally derived allele. We also evaluated 48 cases likely to have a somatic initial mutation; in this group the initial mutation arose on paternal or maternal chromosomes with approximately equal frequency. There was no statistically significant difference in the average age of fathers of children with new paternal germline mutations from the average age of fathers of children with new maternal germline mutations or somatic initial mutations. Combining the data with that from previous reports from other groups, the proportion of new germline mutations arising on a paternally derived allele is 85% (based on 72 cases; 95% confidence interval = 76-93%). This number can be useful in the genetic counseling of some families with retinoblastoma.

Adult↗
PubMed1996

Ultrafiltration of the waste plasma effluent from cardiopulmonary bypass circuit contents processed with a cell-washing device.

Blood conservation methods are commonly practiced throughout most hospitals that conduct cardiothoracic surgery. In an effort to reduce patients' exposure to homologous blood products and due to cost effectiveness of blood conservation techniques, this present study combines autotransfusion of the remaining blood in the extracorporeal circuit and ultrafiltration of the plasma effluent, and describes the resulting product. Seven patients, greater than 19 years of age, requiring cardiopulmonary bypass (CPB) were incorporated into this study. Exclusion criteria included age limitation. At termination of CPB, the remaining blood in the circuit was transferred to an autotransfusion machine and processed. Plasma (1054 +/- 206 ml) effluent was collected directly from the centrifugal bowl and processed through a ultrafiltrator, with a constant flow rate and negative pressure, until the plasma effluent concentrated down to an end processed volume of approximately 150 ml. The following variables were either measured or calculated: plasma-concentrate volumes per three minute interval, inlet/outlet pressures of an ultrafiltrator, transmembrane pressure (TMP), plasma free hemoglobin, fibrinogen, total protein, and colloid osmotic pressure. The average ultrafiltrate volume taken off from the plasma effluent was 828 +/- 237 ml, with an average ultrafiltrate volume of 115 ml in every three minute interval. The TMP did not change over the first 15 minutes of processing but became significantly elevated at the 18th minute interval and continued to increase and reach a maximum TMP of 286.5 +/- 2.1 mmHg at the end of concentration. Fibrinogen levels increased from pre-concentration values of 118.2 +/- 64 to 317 +/- 177 mg/dl (p = .03) along with increases in plasma free hemoglobin from 97.7 +/- 46 to 402.1 +/- 180 mg/dl (p = .0002). The total protein concentration increased by over 330% from baseline values. Ultrafiltrating plasma effluent from autotransfused cell salvaged CPB circuit contents could prove beneficial, but further study is required to discover ways to separate unfavorable products, such as activated platelet-leukocyte products and reduced plasma free hemoglobin, and to lower heparin concentrations of the plasma-concentrate.

Blood Transfusion, Autologous↗
PubMed1986

Transcriptional regulation of serum amyloid A gene expression.

Serum amyloid A (SAA) is a plasma apolipoprotein produced by the liver in response to inflammatory stimuli. The murine SAA gene family is made up of three genes, SAA1, SAA2, and SAA3, plus a pseudogene. The SAA1 and SAA2 genes are highly homologous while the SAA3 gene has diverged substantially from the other two genes. Using small fragments from the cloned genes, we have analyzed the expression of each gene in the SAA family. Within 12 h after endotoxin administration, total liver SAA mRNA increases by 2000-fold, reaching approximately 20,000 transcripts/cell. Each gene accounts for approximately one-third of total SAA mRNA transcripts at this time. The increase is specific, since the levels of the mRNAs encoding albumin and apolipoprotein A-I in liver decrease 2-fold by 24 h. This correlates with a 2-fold decrease of the serum concentrations of these two proteins as well as their in vitro protein synthesis in primary hepatocytes. SAA1+2 mRNAs maintain their maximum levels until 36 h after lipopolysaccharide administration, while SAA3 mRNA is degraded to 20% its maximal level. As assayed by in vitro transcription in isolated hepatocyte nuclei, total SAA gene transcription increases at least 300-fold during the inflammatory response. The transcription rates of the individual SAA genes are similar during the initial stages of this response, reaching peak levels at 3 h. A comparison of the rates of SAA gene transcription and SAA mRNA accumulation suggests that SAA mRNA levels are regulated during the acute phase response by increased transcription and mRNA stabilization.

Albumins↗
PubMed1986

Structure of the murine serum amyloid A gene family. Gene conversion.

Serum amyloid A (SAA) is an apolipoprotein produced by the liver in response to inflammation; the levels of SAA mRNA and SAA protein increase at least 500-fold within 24 h. We have obtained clones of all three genes and pseudogene that make up the murine SAA gene family. Two of the genes have 96% sequence homology over their entire length, including introns and flanking sequences 288 base pairs (bp) 5' and 443 bp 3' to the genes: an overall length of 3215 bp. The sharp boundaries between homologous and nonhomologous sequences and the absence of interspersed repeated sequences there suggest that conversion has occurred between these two genes. The homologous regions are bounded by short inverted repeats containing alternating purine and pyrimidine residues, as described for other gene conversion units. The third SAA gene has evolved separately, although all are closely linked on chromosome 7. Comparison of the upstream regions of the SAA genes with those of the rat fibrinogen genes, whose expression is also induced by inflammation, reveals sequences common to all six genes which are very improbable on a random basis.

Amyloid↗
PubMed1986

The sequence and structure of a new serum amyloid A gene.

The acute phase response is characterized by changes in the serum concentrations of many proteins. A 1000-fold increase in the concentration of serum amyloid A (SAA) protein occurs within 24 hours of LPS injection in the mouse. We have isolated a cDNA clone and its corresponding genomic phage for a third, previously unreported SAA protein. The sequence of the cDNA, the gene's exons and neighboring DNA are presented along with the mapping evidence supporting the gene structure.

Amino Acid Sequence↗
PubMed1984

Kinetics of glutathione transferase, glutathione transferase messenger RNA, and reduced nicotinamide adenine dinucleotide (phosphate):quinone reductase induction by 2(3)-tert-butyl-4-hydroxyanisole in mice.

The mechanisms by which 2(3)-tert-butyl-4-hydroxyanisole (BHA) protects against chemical carcinogenesis and toxicity include enhancement of the activities of several detoxification enzymes. In previous studies, 14-day administration of BHA to female CD-1 mice at 0.75% of the diet led to large increases in cytosolic glutathione transferase (EC 2.5.1.18) and reduced nicotinamide adenine dinucleotide (phosphate) dehydrogenase (quinone) (EC 1.6.99.2) [NAD(P)H:quinone reductase; DT-diaphorase] specific activities in several tissues, and elevated hepatic glutathione transferase messenger RNA. In the present study, one day of dietary BHA significantly increased NAD(P)H:quinone reductase and glutathione transferase activities in the liver, kidney, and proximal small intestine, and NAD(P)H:quinone reductase activity in the forestomach and lung. In the proximal small intestine, glutathione transferase specific activities toward 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene rose to 2.6 and 8 times those of control, respectively, and NAD(P)H:quinone reductase specific activity doubled, within 1 day on the BHA diet. Six hr after a single p.o. dose of BHA (620 mg/kg), intestinal glutathione transferase specific activities were 30 to 50% above those of control mice. In liver, the kinetics of increase of glutathione transferase messenger RNA were in accord with increased synthesis as the mechanism of elevation of glutathione transferase activity in response to BHA. Although changes in mixed-function oxygenase activities have been reported to occur more rapidly, the kinetics of the response of glutathione transferase and NAD(P)H:quinone reductase specific activities to BHA indicates that nonoxidative detoxification potential is substantially enhanced within 24 hr or less after initiation of BHA administration.

Animals↗
PubMed1984

Induction of interleukin 1 messenger RNA and translation in oocytes.

Macrophages and P388D1 murine cultured cells produce interleukin 1 (lymphocyte-activating factor) when stimulated with lipopolysaccharide or other agents. Poly A+ RNA extracted from either type of stimulated cells and injected into Xenopus oocytes causes synthesis of material with the biologic and biochemical properties of interleukin 1. It potentiates lectin-mediated thymocyte proliferation, and it has the molecular dimensions of interleukin 1, as determined by gel exclusion chromatography. RNA from either cell type causes the synthesis of interleukin 1 with an isoelectric point of 4.8 to 5.0. RNA prepared from unstimulated macrophages or P388D1 cells does not cause interleukin 1 production by oocytes. We conclude that the amount of interleukin 1 mRNA increases greatly after stimulation of either cell type, and oocytes carry out any modifications of the polypeptide necessary for activity. The kinetics of interleukin 1 mRNA accumulation and of interleukin 1 production by macrophages and P388D1 cells are compared.

Animals↗
PubMed1983

Increased synthesis of glutathione S-transferases in response to anticarcinogenic antioxidants. Cloning and measurement of messenger RNA.

Glutathione S-transferase activities in mouse hepatic cytosols are elevated as much as 11-fold following the administration of BHA (2(3)-tert-butyl-4-hydroxyanisole), a widely used antioxidant food additive. Ethoxyquin (1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline) and disulfiram [bis(diethyldithiocarbamyl)disulfide] also enhance the activities of glutathione S-transferases and certain other enzymes. Each of these compounds protects rodents against mutagenic and carcinogenic metabolites. A major (pI 8.7) and a minor (pI 9.3) component of the family of mouse hepatic glutathione S-transferases have been purified to homogeneity. These transferases are immunologically cross-reactive, and have a high degree of NH2-terminal sequence homology (but are not identical). The enzymes differ in a number of molecular and catalytic properties. The transferases are 12-fold elevated by dietary BHA as demonstrated by immunotitration. The mRNA for the major glutathione S-transferase is increased more than 20-fold in the liver RNA of BHA-fed mice, as determined by translation of total liver mRNA and characterization of the products by immunoprecipitation and sodium dodecyl sulfate-gel electrophoresis or by two-dimensional gel electrophoresis. A cDNA plasmid complementary to glutathione S-transferase mRNA was constructed. Translation of liver mRNA selected by hybridization with this plasmid gave products similar to or identical with glutathione S-transferase polypeptides. The cDNA insert has been partially sequenced and its orientation has been determined. Its sequence corresponds to the NH2-terminal region (beginning at residue 9) of the amino acid sequence of the glutathione S-transferase with pI 9.3. Hybridization of the 32P-labeled cDNA plasmid with total liver RNA indicates a 26-fold increase in homologous mRNA in response to the feeding of BHA.

Amino Acid Sequence↗
PubMed1982

Regulation of synthesis of amyloid A-related protein.

The concentration of serum amyloid A polypeptide (SAAL) increases greatly during the acute phase responses to infection or inflammation. We find that SAAL synthesis comprises 2.5% of murine hepatic protein synthesis after lipopolysaccharide (LPS) administration, but much less in normal liver. SAAL messenger RNA (mRNA) in liver increases at least 500-fold above the normal level. A recombinant plasmid homologous to SAAL mRNA has been isolated, as has most of the mouse genome DNA encoding the plasmid's nucleotide sequence. This gene is transcribed into RNA much more frequently after LPS administration than it is in normal liver. In a number of other mammalian genes, cytosine methylation is inversely related to the rate of transcription. Methylation of CCGG sequences in hepatic DNA homologous to the recombinant plasmid has been examined. Little or no change is found after LPS administration. This suggests that other factors are responsible for the increase in SAAL mRNA in the acute phase response.

Amino Acid Sequence↗
PubMed1981

Repeated DNA sequences near the 5'-end of the silk fibroin gene.

Four different repeated sequence elements have been found in cloned silk moth DNA, extending from 5700 base pairs upstream from the silk fibroin gene to 600 base pairs within its intervening sequence. Only 2 of the 12 overlapping restriction fragments examined, ranging from 164 to 1800 base pairs in length, do not contain a repeated sequence. The 830 base pairs adjoining the 5'-end of the fibroin gene hybridize with only one sequence in the Bombyx mori genome. Fibroin gene transcription initiates within this single-copy DNA at least 500 base pairs downstream from any repeated DNA sequence. The data show that repeated sequences comprise a major portion of the DNA flanking this developmentally regulated gene but not the DNA immediately 5' to it; that an intervening sequence can contain a repeated element; and that repeated sequences can be interspersed with one another as well as with single-copy DNA in a typical animal genome. In addition, filter transfer hybridization can be used to quantitate repetition frequency and sequence divergence and to distinguish patterns of repeated sequence organization.

Animals↗
PubMed1981

Discrete-length repeated sequences in eukaryotic genomes.

Two of the four repeated DNA sequences near the 5' end of the silk fibroin gene hybridize with discrete-length families of repeated DNA. These two families comprise 0.5% of the animal's genome. A repeated sequence with a conserved length has also been found in the short class of moderately repeated sequences in the sea urchin. The discrete length, interspersion, and sequence fidelity of these moderately repeated sequences suggests that each has been multiplied as a discrete unit. Thus, transposition mechanisms may be responsible for the multiplication and dispersion of a large class of repeated sequences in phylogenetically diverse eukaryotic genomes. The repeat we have studied in most detail differs from previously described eukaryotic transposable elements: it is much shorter (1300 base pairs) and does not have terminal repetitions detectable by DNA hybridization. A simple technique for identifying such discrete-length repeated sequences is described.

Animals↗
PubMed1981

Induction of hepatic synthesis of serum amyloid A protein and actin.

Major changes in the mRNA population of murine liver occur after administration of bacterial lipopolysaccharide, an agent that causes increases in the concentrations of acute-phase serum proteins. The mRNA for one of these, serum amyloid A, is increased at least 500-fold compared to the normal level. It becomes one of the most abundant hepatic mRNAs, and serum amyloid A synthesis comprises about 2.5% of total hepatic protein synthesis in the acute-phase response. Its synthesis is tissue-specific in that amyloid A mRNA was not detected in the kidney, an important site of amyloid fibril accumulation. The protein synthesized in largest amount by acute-phase liver tissue in culture is cytoplasmic actin. Its relative rate of synthesis is increased about 5-fold compared to the normal tissue; that of serum albumin is decreased to about one-third of its normal rate. The concentration of mRNA for serum albumin is decreased by a similar amount. Starting with induced liver RNA, we have constructed a recombinant plasmid containing most of the DNA sequence encoding the serum amyloid A polypeptide.

Actins↗
PubMed1974

Cleavage of replicating forms of mitochondrial DNA by EcoRI endonuclease.

Digestion of mouse L cell mitochondrial DNA with EcoRI restriction endonuclease produces two linear duplex fragments comprising 86.3 +/- 2.0% and 14.2 +/- 1.0% of the circular genome length (16,000 +/- 470 nucleotide pairs). Digestion of human HeLa cell mitochondrial DNA with EcoRI produces three linear duplex fragments comprising 49.2 +/- 1.0%, 44.4 +/- 0.9%, and 6.4 +/- 0.4% of the circular genome length (16,590 +/- 710 nucleotide pairs). These fragments are shown to be generated by cleavage in unique regions of the mouse and human mitochondrial DNAs. An electron microscopic analysis of partially replicated molecules cleaved by EcoRI establishes a unidirectional mode of DNA replication for L cell mitochondrial DNA. The origin for DNA replication is located on the larger EcoRI fragment at a position that is 1,890 +/- 250 nucleotide pairs (11.8 +/- 1.2% of the circular genome length) from the proximal restriction site. Replication proceeds unidirectionally away from this restriction site throughout the length of the larger EcoRI fragment. Analysis of L cell, D-loop mitochondrial DNA cleaved by EcoRI indicates that a unique sequence is synthesized in formation of the D-loop in these nonreplicating molecules. The origin of D-loop synthesis is located on the larger EcoRI fragment at a position 1,760 +/- 180 nucleotide pairs (11.0 +/- 1.1% of the circular genome length) from the proximal restriction site and is, therefore, the origin for unidirectional displacement replication.

Animals↗
PubMed1974

Replication and transcription of eukaryotic DNA in Escherichia coli.

Fragments of amplified Xenopus laevis DNA, coding for 18S and 28S ribosomal RNA and generated by EcoRI restriction endonuclease, have been linked in vitro to the bacterial plasmid pSC101; and the recombinant molecular species have been introduced into E. coli by transformation. These recombinant plasmids, containing both eukaryotic and prokaryotic DNA, replicate stably in E. coli. RNA isolated from E. coli minicells harboring the plasmids hybridizes to amplified X. laevis rDNA.

Animals↗
PubMed1973

Mapping of simian virus 40 early functions on the viral chromosome.

The simian virus 40 (SV40) DNA segment in the nondefective adenovirus 2-SV40 hybrid, Ad2(+)ND(4), is colinear with the segment between 0.11 and 0.59 SV40 fractional length from the site at which the R(1) restriction endonuclease cleaves SV40 DNA. This specifies the region of the SV40 DNA molecule which induces the early SV40 antigens: U antigen, tumor specific transplantation antigen, and T antigen. A variant of Ad2(+)ND(4), called Ad2(+)ND(4del), was found which has a deletion of the DNA segment between 0.50 and 0.57 SV40 fractional length from the R(1) endonuclease cleavage point.

Adenoviridae↗
PubMed1973

Cleavage of circular, superhelical simian virus 40 DNA to a linear duplex by S1 nuclease.

S(1) nuclease, the single-strand specific nuclease from Aspergillus oryzae can cleave both strands of circular covalently closed, superhelical simian virus 40 (SV40) DNA to generate unit length linear duplex molecules with intact single strands. But circular, covalently closed, nonsuperhelical DNA, as well as linear duplex molecules, are relatively resistant to attack by the enzyme. These findings indicate that unpaired or weakly hydrogen-bonded regions, sensitive to the single strand-specific nuclease, occur or can be induced in superhelical DNA. Nicked, circular SV40 DNA can be cleaved on the opposite strand at or near the nick to yield linear molecules. S(1) nuclease may be a useful reagent for cleaving DNAs at regions containing single-strand nicks. Unlike the restriction endonucleases, S(1) nuclease probably does not cleave SV40 DNA at a specific nucleotide sequence. Rather, the sites of cleavage occur within regions that are readily denaturable in a topologically constrained superhelical molecule. At moderate salt concentrations (75 mM) SV40 DNA is cleaved once, most often within either one of the two following regions: the segments defined as 0.15 to 0.25 and 0.45 to 0.55 SV40 fractional length, clockwise, from the EcoR(I) restriction endonuclease cleavage site (defined as the zero position on the SV40 DNA map). In higher salt (250 mM) cleavage occurs preferentially within the 0.45 to 0.55 segment of the map.

Aspergillus↗