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Biomedical subjects

J Parker

Publications and source records attributed to J Parker.

At least 325 records · Page 18Linked to original sources
PubMed1978

Immune function in healthy relatives of patients with malignant disease.

Immune function studies of healthy members of families with multiple lymphoreticular neoplasms were compared with those of healthy members of families with multiple cancers and families with no known history of cancer. The lymphoma family group had a significantly elevated serum level of IgM and diminished responses to the Candida albicans skin test antigen and the T-cell mitogen concanavalin A. Subjects with Epstein-Barr virus-viral capsid antigen titers greater than or equal to 160 had lower responses to mitogens.

Adolescent↗
PubMed1977

Human B lymphocytes in giemsa stained preparations.

A mixed antiglobulin procedure has been developed to provide simultaneous study of cell surface immunoglobulin and detailed cytological features in Giemsa stained preparations. The percentage of surface immunoglobulin bearing lymphocytes, monocytes and granulocytes changed dramatically when lymphocytes were incubated at 37 degrees C, or following sheep erythrocyte rosette enrichment procedures.

Animals↗
PubMed1977

Fine-structure mapping of the rts, rplK, rplL, and rpoB genes of Escherichia coli.

The specialized transducing phage lambdacI857S7drifd18 was used as a donor in a transductional mapping of four genes in the rif region of the Escherichia coli genome. The gene order was rts-2.9-rplL-0.8-rpoB, where the numbers indicate intermarker distances in kilobases. The possible orientation of these genes with respect to each other and to neighboring genes is discussed.

Bacterial Proteins↗
PubMed1976

A transducing bacteriophage lambda carrying the structural gene for elongation factor Ts.

A specialized transducing bacteriophage lambdadpolCdap D-9 has been isolated that carries the structural gene for EF-Ts1 (tsf). The presence of EF-Ts among the proteins synthesized under the direction of this phage in UVL-inactivated cells has been detected by two-dimensional gel electrophoresis and has been verified by antibody precipitation. In an induced lysogen of this phage the relative rate of synthesis of EF-Ts is increased 4-fold. Evidence is presented which suggest that the structural genes for ribosomal protein S2 (rpsB) and RNA polymerase sigma factor (sit) also lies on lambdadpolCdap D-9.

Coliphages↗
PubMed1976

A relaxed mutant with an altered ribosomal protein L11.

Relaxed mutants of Escherichia coli have been isolated which have an altered electrophoretic mobility of ribosomal protein L11. It can be shown that reversion to stringency in one of these mutants occurs simultaneously with a reversion of L11 protein to tis normal mobility. The L11 structural gene, rplK, maping near rif, is carried by the bacteriophage lambdacI857S7drifd18, and is most likely identical with relC.

Bacterial Proteins↗
PubMed1976

Isolation of transducing phage carrying rps T, the structural gene for ribosomal protein S20.

Lambda transducing phages carrying segments of the Escherichia coli chromosome in the dapB region have been isolated in their in vivo gene products analyzed by two-dimensional gel electrophoresis. One of these phages, lambdaddapB-2, carries the structural genes for ribosomal protein S20 (rps T) and isoleucyltransfer RNA synthetase (ileS.) The most likely gene order is thr-rpsT-ileS-dapB-pyrA.

Bacterial Proteins↗
PubMed1976

Liver hernia diagnosed by liver scan and confirmed by angiography.

A right-sided diaphragmatic hernia contining a portion of liver is presented. The diagnosis was made by liver scan and confirmed by selective angiography. The clinical and radiologic findings are discussed. The arteriogram of the herniated liver is the first angiographic demonstration of this entity.

Angiography↗
PubMed1976

Isolation of a lambda transducing bacteriophage carrying the relA gene of Escherichia coli.

In Escherichia coli the relA and pyrG loci are 99% cotransducible. On the basis of this knowledge, we have isolated lambdacI857S7dpyrG transducing bacteriophages carrying both the pyrG and relA genes. Single lysogens of this bacteriophage show basal levels of ppGpp that are 10-fold higher than normal. Stringent factor is present among the gene products synthesized by lambdadpyrG relA after infection of ultraviolet-killed cells, as analyzed by polyacrylamide gel electrophoresis. The intracellular content of stringent factor, as determined by enzymatic activity, rises 20-fold after induction of a single lysogen of lambdadpyrG relA. As measured by two-dimensional gel electrophoresis, the amount of stringent factor in an exponentially growing strain carrying a pyrG relA plasmid is at least 10-fold greater than in a normal strain. These data constitute strong evidence that stringent factor is the relA gene product.

Amino Acids↗
PubMed1976

Syphilitic aortic regurgitation. An appraisal of surgical treatment.

During the 10 years from 1964 to 1973, fifteen patients with severe syphilitic aortic regurgitation were treated surgically at the National Heart Hospital. In thirteen the valve was replaced and in two it was repaired. In addition four had replacement of an aneurysmal ascending aorta with a Dacron graft and seven some form of plastic repair to the coronary ostia. Three patients died within 1 month of surgery and a further six during the follow-up period which varied from 1 to 55 months (mean 25-5). The six survivors have been followed-up for an average of 33 months. Factors contributing to this high mortality were analysed and it was found that the mean duration of effort dyspnoea was 22 months in the survivors compared with 48 months in those who had died. Similarly the average duration of nocturnal dyspnoea was 4 months in the survivors compared with a mean of 8 months in those who had died. Only six out of the fifteen patients had angina; this was present in two of the survivors and in four of the fatalities. The pulse pressure, heart size, and haemodynamic findings were similar in the two groups. The prognostic value of an elevated erythocyte sedimentation rate was also examined. It was concluded that preoperative investigations should include aortography, coronary arteriography, an assessment of left ventricular function, and whenever possible myocardial biopsy. These data were interpreted as suggesting that patients should be referred for surgery at an earlier stage in the disease--certainly before the onset of cardiac failure and--and that if this more aggresive attitude was adopted, as it has been in non-syphilitic cases of aortic valve disease, the present high mortality in this group would be reduced.

Adult↗
PubMed1975

The role of noradrenaline, dopamine and 5-hydroxytryptamine in the hyperactivity response resulting from the administration of tranylcypramine to rats pretreated with lithium or rubidium.

1. The administration of 15 mg/kg tranylcypromine sulphate (Tc) to rats which have been given lithium chloride (LiCl) in the diet (30 mmol/kg dry food) for 14 days produces hyperactivity within 4 hrs, and this lasts for at least 4 further hours. 2. If LiCl is replaced by rubidium chloride (RbCl) at the same dose, the hyperactivity following Tc is increased and it appears within 2 hrs. 3. 5-Hydroxytryptamine (5HT) accumulation after a monoamine oxidase inhibitor (Tc) is increased 46% and 85% respectively above control values by LiCl and RbCl administration. 4. The hyperactivity produced by the above combinations is inhibited by alpha-methyl-p-tyrosine (alphampt). The inhibition is more effective following LiCl than RbCl treatment. 5. After sodium chloride (NaCl) and LiCl treatment, but not after RbCl treatment, the combination of alphampt and Tc produced rat brain concentrations of dopamine (DA) significantly below control values. 6. The smaller increase of brain noradrenaline (NA) after Tc and RbCl suggests that a lower percentage of NA is being metabolised by MAO. The greater decrease of NA after giving alphampt to RbCl and LiCl treated rats suggests an increased "turnover" rate of Na. 7. The hyperactivity syndrome seen in rats after the administration of LiCl or RbCl and Tc is dependent upon both 5HT and dopamine mechanisms.

Animals↗
PubMed1975

An experimental inactivated vaccine against bluetongue.

Bluetongue virus grown in BHK cells was shown to be inactivated in concentrations of betapropiolactone (BPL) higher than 0-15 per cent. When the virus, inactivated with 0-2 per cent BPL and prepared as a double emulsion vaccine, was injected into Cypriot sheep, no untoward reactions were observed and neutralising antibodies developed. The antibody titre reached a high level and persisted for at least a year. After re-vaccination, a secondary response was observed. A bivalent vaccine elicited a response to both virus types incorporated. The possibilities of using a polyvalent inactivated vaccine are discussed.

Animals↗
PubMed1975

Inactivation of African horse-sickness virus by betapropiolactone and by pH.

The inactivation of several types of African horse sickness virus (AHSV) by pH and by betapropiolactone (BPL) was studied. At 19 degrees - 22 degrees C the virus was stable between pH 6.0 and 10.4, whether suspended in mouse brain or in serumfree buffer. Below pH 5.6 and above pH 10.9, more than 99 per cent of infectivity was inactivated within 15 minutes. The addition of 50 per cent serum did not influence pH stability. Disinfection in the presence of citric acid and caustic soda is briefly discussed. Inactivation by BPL was complete within 30 minutes at 37 degrees C, yet incomplete after 15 hours at 4 degrees C. Types 3 and 9 virus grown in suckling mouse brain and types 1, 3 and 9 produced in pig kidney cells were equally susceptible to 0.1 per cent BPL, more than 99.9 per cent being inactivated. The effectiveness of BPL was reduced at least 10-fold by the addition of 50 per cent serum. No infective virus was detected following incubation of either tissue culture virus with 0.2 per cent BPL or of mouse brain virus with 0.3 per cent BPL. Virus suspensions exposed to 0.3 per cent BPL required buffering with Tris of at least 0.05 molar strength in order to maintain the pH within an acceptable range. Inactivated antigens prepared with 0.4 per cent or lower concentrations of BPL were immunogenic in guinea pigs.

African Horse Sickness Virus↗