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Biomedical subjects

M Sheppard

Publications and source records attributed to M Sheppard.

At least 91 records · Page 5Linked to original sources
PubMed1987

Nucleotide sequence changes in thymidine kinase gene of herpes simplex virus type 2 clones from an isolate of a patient treated with acyclovir.

To identify the nucleotide changes that occur in drug-induced thymidine kinase (TK) mutants of herpes simplex virus type 2 (HSV-2), we compared the nucleotide sequences of the tk genes of two mutant HSV-2 clones isolated from a patient who had been treated with acyclovir [9-(2-hydroxyethoxymethyl)guanine; ACV] with the nucleotide sequence of the parental TK+ HSV-2(8703) strain isolated from the same patient. One of the mutants, TK-altered (TKA) HSV-2(9637), was ACV resistant but induced the incorporation of [14C]thymidine into the DNA of infected rabbit skin cells. The nucleotide sequence of the tk gene of mutant TKA HSV-2(9637) had a single change (G to A) at nucleotide 668, which would cause an arginine-to-histidine substitution at amino acid residue 223 of the TK polypeptide. The second ACV-resistant mutant, TK- HSV-2(8710), did not induce detectable incorporation of [14C]thymidine into the DNA of infected rabbit skin cells. This mutant exhibited a deletion of a single base at nucleotide 217 of its nucleotide sequence. This deletion would cause a frameshift mutation at amino acid residue 73 and chain termination at amino acid residue 86 of the TK polypeptide. The nucleotide sequence of TK+ HSV-2(8703) was the same as that of the laboratory strain, TK+ HSV-2(333). The nucleotide sequence of a bromodeoxyuridine-resistant TK- HSV-2(333) mutant of TK+ HSV-2(333) also exhibited a single-base deletion, but at nucleotide 439. This deletion would cause a frameshift mutation at amino acid residue 147 and chain termination at amino acid residue 182. The frameshift mutations of TK- HSV(8710) and TK- HSV-2(333), respectively, occurred in sequences in which C was repeated three times and G was repeated seven times. The results raise the possibility that TK- frameshift mutations of HSV-2 may be common.

Acyclovir↗
PubMed1987

Hypomagnesaemia causing myopathy and hypocalcaemia in an alcoholic.

A well-nourished alcoholic patient developed a subacute myopathy which responded rapidly to correction of severe hypomagnesaemia. The finding of profound hypocalcaemia prompted the measurement of serum magnesium. Magnesium deficiency should be looked for in any alcoholic patient with a myopathy as the prognosis seems better than in many other forms of alcoholic myopathy. Correction of the magnesium deficiency corrects the hypocalcaemia without the need for calcium supplementation.

Aged↗
PubMed1987

Second-generation pseudorabies virus vaccine with deletions in thymidine kinase and glycoprotein genes.

A modified-live pseudorabies virus (PRV) vaccine, designated PRV(dlg92/d1tk), with deletions in the thymidine kinase (tk) and glycoprotein-gIII (g92) genes, was derived from the PRV (Bucharest [BUK]-d13) vaccine strain. The vaccine virus also contained a deletion in glycoprotein gI. Despite 3 deletions, PRV(dlg92/d1tk) replicated to high titers in cell culture from 30 C to 39.1 C. Enzyme assays and autoradiography revealed that PRV(dlg92/d1tk) did not induce a functional tk activity in infected tk- RAB(BU) cells (rabbit skin). Rabbit skin cells were infected with PRV(dlg92/d1tk), with vaccine strains derived from BUK or Bartha K strains of PRV or with the virulent Illinois (ILL), Indiana-Funkhauser (IND-F), and Aujeszky (Auj) strains of PRV and were labeled with [3H]mannose from 4 or 5 to 24 hours after infection to investigate whether these viruses induced the synthesis of glycoprotein gIII. Nonionic detergent extracts were prepared and immunoprecipitated with antisera from pigs vaccinated with tk(-)-PRV(BUK-d13) or tk+-Bartha K, pigs vaccinated with tk+-PRV(BUK) strains and then challenge exposed to tk+-PRV(IND-F), naturally infected domestic or feral pigs, and pigs vaccinated with tk-)-PRV(dlg92/d1tk). Mouse monoclonal antibodies against PRV glycoproteins gIII, gp50, and gII were also studied. After immunoprecipitation, labeled PRV-specific proteins were analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis and autoradiography. The PRV glycoprotein-gII complex, but not glycoprotein gIII, was synthesized in PRV(dlg92/d1tk)-infected cells. Glycoprotein gII and gIII were made in cells infected with PRV vaccine strains BUK, Bartha K, and BUK-d13 and with virulent PRV strains ILL, IND-F, and Auj. Cells infected with PRV(dlg92/d1tk) and with PRV strains ILL, IND-F, Auj, Bartha K, BUK, and BUK-d13, excreted into the cell culture medium a highly sulfated glycoprotein gX of about 90 kilodaltons. Antibodies to glycoprotein gIII were not detected in the sera of pigs inoculated with PRV(dlg92/d1tk), but were found in all other swine sera.

Animals↗
PubMed1986

Differentiation between virulent and avirulent strains of infectious laryngotracheitis virus by DNA:DNA hybridization using a cloned DNA marker.

The DNAs of virulent and avirulent strains of infectious laryngotracheitis virus (ILTV) showed greater than 96% homology by reciprocal DNA:DNA hybridization. Nevertheless, by use of selected restricted DNA fragments, it was possible to differentiate strains according to pathotype more readily than by the more laborious restriction enzyme analysis. Restricted DNA fragments were successfully cloned into Escherichia coli HB101 cells and could be used not only for pathotyping ILTV strains but also for their differentiation from other avian viruses.

Cloning, Molecular↗
PubMed1985

Analysis of the HSV-2 early AG-4 antigen.

Genital herpes simplex virus type 2 (HSV-2) infections can be distinguished from present or past HSV-1 infections by an AG-4 antigen complement fixation assay. The assay which utilizes a 4 hour HSV-2 infected cell extract prepared at a multiplicity of infection (MOI) of 1.0 PFU/cell, appears to consist of several viral proteins. Studies using monoclonal antibodies, polyclonal rabbit hyperimmune serum, HSV-1 X HSV-2 intertypic recombinant viruses and polyacrylamide gel electrophoresis suggest that ICP 8 may be one of the major antigens involved in the complement fixing reaction. It is probable that the success of the assay is not due to a true type specificity but rather a threshold phenomenon in which HSV-2 extracts contain more early viral antigens (including ICP 8) and sera from HSV-2 patients contain more complement fixing antibody to these antigens.

Animals↗
PubMed1985

Expression of the herpes simplex virus type-2 major DNA-binding protein (ICP8) gene in COS-1 cells.

By the use of an SV40 origin of replication plasmid vector and the COS-1 cell system, expression of the gene encoding the herpes simplex virus type-2 (HSV-2) major DNA binding protein (ICP8) has been achieved. The HSV-2 4.5 kb BglII 0 DNA fragment containing the ICP8 coding region was inserted into the plasmid vector pSVOd containing the SV40 origin of replication. Transfection of COS-1 cells by the resultant recombinant plasmid (pSVOd20), and subsequent multiplication of this plasmid, led to the production of the HSV-2 major DNA binding protein in sufficient quantities to allow its detection with either monoclonal or polyclonal antibodies as well as sera taken from HSV-2 patients.

Animals↗
PubMed1983

An ELISA technique to detect IgG antibody to the early herpes simplex virus type 2 (HSV-2) antigen AG-4 in HSV-2 patients.

An ELISA system, based on urease activity was used for the detection and titration of IgG to the immediate early AG-4 antigen in sera from HSV-2 patients. It detected low levels of IgG to the AG-4 antigen in 32% of patients' sera known to contain complement fixing antibody to the antigen. Furthermore, the sensitivity of the ELISA system was 2- to 10-fold higher than the complement-fixation system depending on when the sera was taken from the HSV-2 patients. The system also allowed the easy detection and quantitation of AG-4 antigen production when various HSV-1 X HSV-2 intertypic recombinant viruses were used to infect BHK-21 cells.

Adult↗
PubMed1982

A preliminary investigation of the effect of age, sex and time of collection on the feeding patterns of Glossina morsitans morsitans Westw. in Zambia.

Glossina morsitans morsitans were collected during the dry season of 1975 from two areas in the Luangwa Valley (Zambia) and from one of the areas in the wet season of 1976. In all, 1,190 flies were analysed for sex, wing fray category and source of bloodmeal. Differences in the feeding patterns in the morning and afternoon collections reflected host behaviour. Warthog consistently emerged as a major host but there appeared to be some local variation resulting from seasonal and diurnal availability of hosts.

Age Factors↗
PubMed1982

Comparison of restriction endonuclease profiles of DNA from local herpes simplex virus type 2 (HSV-2) strains.

Comparisons of restriction endonuclease profiles of DNA isolated from nine genital HSV-2 strains isolated from 1973 to 1981 were made using six restriction endonucleases (Bgl II, Hind III, Xba 1, Eco RI, Bam HI and Hpa I). The only variation detected in the DNA profiles was found with Eco RI and Bam HI, and in each case all the isolates could be classified into two groups. The difference between the two Eco RI groups could be accounted for by the absence of an Eco RI cleavage site from the HSV DNA. However, if comparison of the profiles of Eco RI and Bam HI cleaved DNA of the individual HSV-2 strains is made then this yields four different groups. The complete Bgl II, Xba I, Eco RI and Hpa I restriction endonuclease maps for the DNA from one isolate (HSV-2M1) are shown. Little variation in the DNA profiles can be found in local genital HSV-2 strains isolated over a 9-year period, when individual restriction enzymes are used. Thus, restriction endonuclease analysis has limited use in local epidemiological studies of genital HSV-2 isolates unless a wide variety of restriction endonucleases are used. However, the technique offers rapid differentiation between HSV-2 and HSV-1 local strains by using Hpa I endonuclease cleavage of HSV DNA.

DNA Restriction Enzymes↗
PubMed1982

Early detection of aortic dilatation in ankylosing spondylitis using echocardiography.

Aortic root abnormalities including cusp thickening, subvalvular stenosis, and mild aortic root dilatation are the most common cardiac complications in patients with long standing ankylosing spondylitis (AS). Twenty-three patients with definite idiopathic AS (New York Criteria 1966) and twenty-two matched controls were studied with M-mode echocardiography. Only one of the AS patients had clinical aortic incompetence. Six of the AS patients had mildly dilated aortic roots (normal less than 3.7 cm) with a mean diameter of 3.9 cm (range 3.8 to 4.00 cm). None of the twenty-two controls matched for age, sex and blood pressure had dilated aortic roots, with a mean diameter of 3.3 cm (range 2.9 to 3.6 cm). No correlation existed between aortic dilatation and severity of disease estimated by acute phase proteins--caerulo plasmin, alpha 1-antitrypsin, alpha 1 acid glycoprotein, ferritin and C Reactive protein. Contrary to a previous report, mild aortic root dilatation occurs in long standing cases of AS. Although it is a non-specific finding, it does not appear to be related to age or blood pressure and may therefore be the forerunner of aortic incompetence.

Adolescent↗
PubMed1982

The nervous control of rat somatostatin, glucagon and insulin secretions.

Somatostatin-like-immunoreactivity (SLI), immunoreactive insulin (IRI), glucagon (IRG) and catecholamine concentrations were measured in rat portal plasma during electrical stimulation of the vagus and splanchnic nerves, and during experimentally-induced hypovolaemia and hypoxaemia. Blood pressure, arterial gases and pH were monitored and hepatic blood flow was estimated (EHBF). Stimulation of the vagus nerves induced an increase in IRG and IRI concentrations, but had different influences on SLI level according to the concomitant experimental conditions. Stimulation of the left splanchnic nerve induced a sharp rise in SLI, IRG and catecholamine concentrations, whereas IRI level decreased hypovolaemia and hypoxaemia. Phentolamine treatment augmented the basal IRI, IRG and SLI concentrations. It did not suppress the hypovolaemia-induced rise of IRG and SLI concentrations, but unmasked a strong IRI release. By contrast, propranolol and atropine reduced significantly the A and D cell responses to acute hypovolaemia. These results are consistent with a profound influence of pancreatic nerves on A, B and D cell functions, which should be taken into account for interpretation of results during in vivo experiments.

Animals↗
PubMed1981

In vitro release of cholecystokinin octapeptide-like immunoreactivity from rat brain synaptosomes.

Enriched synaptosome fractions prepared by differential centrifugation and ultracentrifugation of homogenates of rat cortex, striatum, thalamus and hypothalamus contained over 65% of the total immunoreactive cholecystokinin octapeptide (CCK-8) in each area. A calcium-dependent release of immunoreactive CCK-8 from these fractions in vitro in response to 2 depolarizing stimuli (60 mM KCl and 75 microM veratrine) has been demonstrated. Released CCK-8 immunoreactivity showed parallelism when dilutions were compared with the CCK-8 dose-response curve and eluted similarly to synthetic CCK-8 on Sephadex G-50 superfine chromatography. These results provide further evidence for a neurotransmitter or neuromodulator role for CCK-8 in brain.

Animals↗