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Biomedical subjects

J Rush

Publications and source records attributed to J Rush.

At least 55 records · Page 3Linked to original sources
PubMed1989

The 44P subunit of the T4 DNA polymerase accessory protein complex catalyzes ATP hydrolysis.

The genes encoding all three T4 DNA polymerase accessory proteins have been cloned into overexpression plasmids. Induction of cells harboring these plasmids results in the synthesis of each accessory protein at levels that approach 10% of the total cellular protein. The solubility of the accessory proteins after induction at 42 degrees C ranges from about 60% to greater than 95%. A plasmid that allows overexpression of the 44P/62P complex has been manipulated further to overexpress selectively the 44P subunit without 62P, permitting us to assess how each subunit contributes to the properties of the 44P/62P complex. A comparison of 44P and 44P/62P by conventional hydrodynamic techniques shows that 44P forms a subcomplex nearly as large as the 44P/62P complex. In addition, 44P catalyzes DNA-dependent ATP hydrolysis with a specific activity similar to that of the 44P/62P ATPase. However, unlike the 44P/62P complex, the ATPase activity of 44P alone is only slightly stimulated by 45P. This suggests that one role of the 62P subunit is to facilitate a productive interaction of 44P and 45P.

Adenosine Triphosphate↗
PubMed1989

Rapid purification of overexpressed T4 DNA polymerase.

A method for purifying T4 DNA polymerase from cells harboring overexpression plasmids is described. T4 DNA polymerase is precipitated from induced, lysed cells with polyethyleneimine, then extracted and fractionated further with (NH4)2SO4 before chromatography on a column of single-stranded DNA cellulose. This procedure can be completed in three days and consistently provides enzyme preparations which are at least 98% pure. When necessary, one further chromatography step provides T4 DNA polymerase suitable for recombinant DNA applications.

Ammonium Sulfate↗
PubMed1988

Primary structure of T4 DNA polymerase. Evolutionary relatedness to eucaryotic and other procaryotic DNA polymerases.

Bacteriophage T4 gene 43 codes for the viral DNA polymerase. We report here the sequence of gene 43 and about 70 nucleotides of 5'- and 3'-flanking sequences, determined by both DNA and RNA sequencing. We have also purified T4 DNA polymerase from T4 infected Escherichia coli and from E. coli containing a gene 43 overexpression vector. A major portion of the deduced amino acid sequence has been verified by peptide mapping and sequencing of the purified DNA polymerase. All these results are consistent with T4 DNA polymerase having 898 amino acids with a calculated Mr = 103,572. Comparison of the primary structure of T4 DNA polymerase with the sequence of other procaryotic and eucaryotic DNA polymerases indicates that T4 DNA polymerase has regions of striking similarity with animal virus DNA polymerases and human DNA polymerase alpha. Surprisingly, T4 DNA polymerase shares only limited similarity with E. coli polymerase I and no detectable similarity with T7 DNA polymerase. Based on the location of specific mutations in T4 DNA polymerase and the conservation of particular sequences in T4 and eucaryotic DNA polymerases, we propose that the NH2-terminal half of T4 DNA polymerase forms a domain that carries out the 3'----5' exonuclease activity whereas the COOH-terminal half of the polypeptide contains the dNTP-binding site and is necessary for DNA synthesis.

Amino Acid Sequence↗
PubMed1988

Failure of antiviral therapy for acquired immunodeficiency syndrome-related cytomegalovirus myelitis.

We report the first published case (to our knowledge) of histopathologically documented acquired immunodeficiency syndrome-related cytomegalovirus (CMV) myelitis in which antiviral drug therapy was administered. Despite sensitivity of the patient's CMV isolate to therapy with both ganciclovir and foscarnet, use of neither of these agents halted progression of central nervous system CMV disease. Higher doses of these drugs or combination therapy may be required to treat acquired immunodeficiency syndrome-related CMV myelitis effectively.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Comparison between clinician-rated and self-reported depressive symptoms in Italian psychiatric patients.

The Inventory for Depressive Symptomatology is a new scale for measuring depressive symptoms. The reliability, validity and correlations between self-report and clinician-rated versions of the scale were examined in 86 Italian psychiatric patients. Results confirmed the validity and internal consistency of the scales. Self-ratings and clinician ratings were highly correlated. Total score on the self-rating scale was generally higher than the corresponding clinician scale score. Item analysis revealed that most items were rated slightly higher by self-report, with the items contributing most to this discrepancy being psychomotor agitation and retardation, self-outlook, and irritable mood. Both quality of mood and psychomotor agitation were more frequently endorsed by self-report than by clinician rating.

Adult↗
PubMed1987

Effect of combinations of difluoromethylornithine (DFMO) and 9[(1,3-dihydroxy-2-propoxy) methyl]guanine (DHPG) on human cytomegalovirus.

Both the nucleoside analog 9[(1,3-dihydroxy-2-propoxy)methyl]guanine (ganciclovir; DHPG) and the polyamine synthesis inhibitor difluoromethylornithine (DFMO) have been reported to inhibit replication of cytomegalovirus (CMV) in vitro. In these studies, DHPG inhibited human CMV replication at concentrations of 0.1 microM or greater, while DFMO was active (and then only inconsistently) at 5 mM or greater. (DFMO was added to cells 3 days before virus to maximize polyamine depletion.) However, DHPG combined with DFMO synergistically inhibited the replication of CMV strain AD169 and one wild-type CMV strain in human foreskin fibroblasts; the effect was evident on both virus yield and plaque formation. The synergistic effect of these two drugs on CMV replication could potentially be exploited clinically to limit drug toxicity or increase efficacy.

Acyclovir↗
PubMed1987

Cloning and expression of T4 DNA polymerase.

The structural gene coding for bacteriophage T4 DNA polymerase (gene 43) has been cloned into inducible plasmid vectors, which provide a source for obtaining large amounts of this enzyme after induction. The T4 DNA polymerase produced in this fashion was purified by an innovative three-step procedure and was fully active.

Genes↗
PubMed1987

Closed nailing of the humerus--from down under.

Closed intramedullary nailing of the humerus using a curved clover-leaf nail (Pohl nail) is a relatively minor operative procedure and is associated with few complications. The technique of the operation when performed from below (29 cases) and also from above (7 cases) is that as described initially by Kuntscher and his colleagues. This paper presents the technique and the experience from 1978 to 1985 with 36 cases (20 for metastatic bone deposits, four in multiple injury patients, three in patients with a severe head injury, four in patients with multiple fractures in the same limb and five in other patients particularly elderly women with osteoporotic bones). This review demonstrates the efficacy of closed intramedullary nailing of the humerus particularly when the nail is inserted into the humerus from below just proximal to the olecranon fossa.

Aged↗
PubMed1981

Closed intramedullary nailing of femoral shaft fractures. A review of one hundred and twelve cases treated by the Küntscher technique.

Since May 1972, the standard treatment of femoral shaft fractures at the Western General Hospital has been the closed femoral nailing technique of Küntscher. We have found that the use of intraoperative skeletal traction eliminates the need for immediate operation, preoperative skeletal traction, or the use of a distraction apparatus to prevent preoperative shortening. By the use of a cross-pinning technique, the closed femoral nailing method has been extended to include severely comminuted fractures of the femoral shaft and fractures of the distal third of the femur, with effective control of shortening and rotatory deformity. This allows early mobilization and discharge from the hospital for patients with these difficult fractures. One hundred and twelve consecutive traumatic fractures of the femoral shaft treated in this manner united within three to six months. The clinical results in terms of early joint movement, early weight-bearing, and rapid discharge from the hospital have been excellent.

Bone Nails↗
PubMed1978

Erythroglycan, a high molecular weight glycopeptide with the repeating structure [galactosyl-(1 leads to 4)-2-deoxy-2-acetamido-glucosyl(1 leads to 3)] comprising more than one-third of the protein-bound carbohydrate of human erythrocyte stroma.

Glycopeptides of molecualr weight range 7,000 to 11,000, unusual in size and structure, have been partially purified from pronase digests of lipid-free human erythrocyte ghosts; we term this fraction "erythroglycan." These substances comprise about one-third of the galactose and glucosamine of the ghost. Methylation analysis of erythroglycan yields mainly 4-linked glucosamine, 3-linked galactose, and 3,6-linked galactose, along with mannose and fucose derivatives. Hydrazinolysis and nitrous acid deamination degrade erythroglycan to galactosyl-2,5-anhydromannose, indicating a repeating structure of galactosyl, (1 leads to 4)-2deoxy-2-acetamidoglucosyl (1 leads to 3). Digestion with the endo-beta-galactosidase from Escherichia freundii gives only partial cleavage of the erythroglycan, probably because of the arborized structure indicated by the branched galactose. Since sphingosine is not detectable after methanolysis by chemical ionization mass spectrometry, and since amino acids are present, we conclude that these substances are probably glycopeptidic in origin and are not "macroglycolipids." Erythroglycan may have the same type of keratan-like core structure as the long chain blood group glycolipids from human erythrocytes and could be a protein-bound carrier of the ABO determinants.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1975

Observations on the induction of bone in soft tissues.

Using bone decalcified with 0-6 N hydrochloric acid as an inducing agent, the inductive capacity of different soft tissue sites was investigated. Muscle and fascia regularly permitted the induction of bone, while spleen, liver and kidney suppressed bone induction. Bone formation could be induced in these organs if living autologous fascia was implanted together with the inducing agent; while bone formation was inhibited when living autologous spleen tissue was implanted with the inducing agent to normally favourable sites. The administration of systemic heparin and the diphosphonate ethane-1-hydroxyl, 1-diphosphonic acid (EHDP) suppressed bone induction. It is suggested that for bone induction to occur in soft tissues, three conditions must be present: 1) an inducing agent; 2) an osteogenic precursor cell; and 3) an environment which is permissive to osteogenesis. The presence of osteogenic inhibitors in spleen, liver and kidney is postulated.

Animals↗