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Biomedical subjects

G L Lawrence

Publications and source records attributed to G L Lawrence.

14 recordsLinked to original sources
PubMed1996

Expression and characterization of equine herpesvirus 1 glycoprotein D in mammalian cell lines.

Equine herpesvirus 1 glycoprotein D (EHV-1 gD) expressed constitutively in mammalian cell lines had similar electrophoretic mobility to gD produced in EHV-1 infected cells but lacked a possibly complexed higher molecular weight form seen in the latter. Recombinant gD was N-terminally cleaved at the same site as gD in EHV-1 infected cells and expression was associated with enhanced levels of cell-cell fusion, indicating a role for EHV-1 gD in cell-to-cell transmission of virus.

Animals↗
PubMed1995

Immunization with glycoprotein C of equine herpesvirus-1 is associated with accelerated virus clearance in a murine model.

The glycoprotein C (gC) gene of equine herpesvirus-1 (EHV-1) was expressed in insect cells by a recombinant baculovirus as several products with apparent molecular weights of 66 kDa-80 kDa. The baculovirus EHV-1 gC products were recognised by monoclonal antibody and by EHV-1 convalescent equine sera, indicating conservation of antigenic determinants and confirming this glycoprotein as a target for the equine immune system. Mice immunized with recombinant EHV-1 gC showed accelerated clearance of EHV-1 from respiratory tissues following intranasal challenge. Virus clearance was accompanied by virus specific antibodies and by cell mediated immune responses measured by a delayed type hypersensitivity reaction and lymphocyte stimulation by killed EHV-1 as antigen.

Animals↗
PubMed1995

Human herpesvirus 6 (strain U1102) encodes homologues of the conserved herpesvirus glycoprotein gM and the alphaherpesvirus origin-binding protein.

The nucleotide sequence of 3,134 bp from the genome of human herpesvirus 6 (HHV-6) strain U1102 was determined. The sequence overlaps and is contiguous with the 21,858 bp nucleotide sequence published by us previously. The sequence reported here encodes two open reading frames, named 18L and 19R. The protein encoded by 18L shares amino acid sequence similarity with the multiply hydrophobic glycoprotein M conserved in the genomes of all herpesviruses sequenced to date. ORF 19R encodes a protein which shares a significant degree of amino acid sequence conservation with the origin-binding protein homologues encoded by members of the alphaherpesvirus subgroup, but does not share detectable amino acid sequence homology with positionally analogous open reading frames present in the genomes of other betaherpesviruses or in the genomes of gammaherpesviruses.

Amino Acid Sequence↗
PubMed1994

Rapid, single-step differentiation of equid herpesviruses 1 and 4 from clinical material using the polymerase chain reaction and virus-specific primers.

Sets of primers were designed which enabled specific amplification of homologous regions of the glycoprotein C and gene 76 genetic loci of equine herpesviruses 1 and 4 (EHV-1 and EHV-4). The resultant virus-specific polymerase chain reaction (PCR) products arising from each loci could be discriminated easily on the basis of size on an agarose gel, allowing rapid differentiation of the two equine herpesviruses. Specificity of the amplifications were confirmed by Southern hybridization and restriction endonuclease digestion. The PCR test was applied to nasal swab samples from weanling foals and to archival aborted fetal tissue samples and the results compared to those obtained by virus isolation. A strong correlation was found between this PCR assay and virus isolation methods of EHV-1 and EHV-4 detection and discrimination.

Animals↗
PubMed1994

Epidemiological investigation of equid herpesvirus-4 (EHV-4) excretion assessed by nasal swabs taken from thoroughbred foals.

Equid herpesvirus-4 (EHV-4) was detected in nasal swabs taken from foals using a PCR based test and this information used to study the epidemiology of EHV-4 disease on three Australian Thoroughbred stud farms in NSW in 1992. There was a very high level of agreement (kappa value of 0.84) between the PCR results and virus isolation using cell culture techniques. There was a strong seasonal distribution of EHV-4 shedding. Twenty-five of 26 positive samples were collected in January and March with the remaining positive sample collected in February. Foals with clinical signs of upper respiratory tract infection per se were no more likely to be shedders of EHV-4 (odds ratio [OR] 1.4, 95% confidence limits [CL] 0.5-3.8). However, EHV-4 was more likely to be isolated from foals exhibiting copious serous or mucopurulent nasal discharge than those with no clinical signs (OR 4.6, 95% CL 1.1-19.0 and OR 2.5, 95% CL 0.8-8.0, respectively). The month of the year was more important than weaning or age as a risk factor for excretion of EHV-4. Male foals and those with a history of respiratory disease that had required veterinary treatment were more likely to shed EHV-4.

Age Factors↗
PubMed1993

Expression of equine herpesvirus 1 glycoprotein D by using a recombinant baculovirus.

Glycoprotein D (gD) of equine herpesvirus 1 (EHV-1) was expressed at the surface of insect cells infected by a recombinant baculovirus. EHV-1 gD was detected as multiple forms (56, 52, and 48 kDa) from 18 to 96 h postinfection. Laboratory animals inoculated with the recombinant EHV-1 gD developed neutralizing antibody responses against both EHV-1 and EHV-4.

Animals↗
PubMed1992

Identification of homologues to the human cytomegalovirus US22 gene family in human herpesvirus 6.

The sequence of 10079 bp corresponding to the overlapping SalI H and SmaI G restriction fragments of the genome of human herpesvirus 6 (HHV-6) strain U1102 was determined. The sequence contains six complete open reading frames (ORFs) and two incomplete ORFs located at the 5' and 3' ends of the SalI H and SmaI G fragments respectively. Seven of these ORFs have recognizable homologues only in the beta-herpesvirus human cytomegalovirus (HCMV), no obvious counterparts being detectable in the genomes of the human alpha-herpesviruses, varicella-zoster virus and herpes simplex virus type 1 or the gamma-herpesvirus Epstein-Barr virus. The DNA sequenced is located proximal to the left repeat of the HHV-6 genome outside the well recognized region encompassing conserved herpesvirus gene blocks. A close colinear relationship is evident between the HHV-6 ORFs identified in this study and their counterparts in HCMV, ORFs UL23, UL24 and UL27 to UL31. Four of the HHV-6 ORFs, SHL1, SHL2, SFL1 and SSL2, are related to members of the HCMV US22 family of proteins, which are themselves tandemly arranged and located predominantly within the unique short and the left end of the unique long region of the prototype HCMV strain AD169 genome. Two adjacent HHV-6 ORFs, SSL1 and SHL3, are related to HCMV UL27. The identification of this gene set in addition to the HHV-6 ORFs with amino acid sequence similarity to the HCMV US22 family indicates a particularly close relationship between these two human herpesviruses, and suggests that the clustering of these related tandemly arranged genes may be a general feature of beta-herpesvirus-type genomes.

Amino Acid Sequence↗
PubMed1990

Human herpesvirus 6 is closely related to human cytomegalovirus.

A sequence of 21,858 base pairs from the genome of human herpesvirus 6 (HHV-6) strain U1102 is presented. The sequence has a mean composition of 41% G + C, and the observed frequency of CpG dinucleotides is close to that predicted from this mononucleotide composition. The sequence contains 17 complete open reading frames (ORFs) and part of another at the 5' end of the sequence. The predicted protein products of two of these ORFs have no recognizable homologs in the genomes of other sequenced human herpesviruses (i.e., Epstein-Barr virus [EBV], human cytomegalovirus [HCMV], herpes simplex virus [HSV], and varicella-zoster virus [VZV]). However, the products of nine other ORFs are clearly homologous to a set of genes that is conserved in all other sequenced herpesviruses, including homologs of the alkaline exonuclease, the phosphotransferase, the spliced ORF, and the major capsid protein genes. Measurements of similarity between these homologous sequences showed that HHV-6 is clearly most closely related to HCMV. The degree of relatedness between HHV-6 and HCMV was commensurate with that observed in comparisons between HSV and VZV or EBV and herpesvirus saimiri and significantly greater than its relatedness to EBV, HSV, or VZV. In addition, the gene for the major capsid protein and its 5' neighbor are reoriented with respect to the spliced ORFs in the genomes of both HHV-6 and HCMV relative to the organization observed in EBV, HSV, and VZV. Three ORFs in HHV-6 have recognizable homologs only in the genome of HCMV. Despite differences in gross composition and size, we conclude that the genomes of HHV-6 and HCMV are closely related.

Amino Acid Sequence↗
PubMed1989

Alpha-, beta- and gammaherpesviruses encode a putative phosphotransferase.

We have sequenced a gene in human cytomegalovirus and a homologous gene in human herpesvirus 6 which could specify a product related to protein kinases. This gene appears to be generic in the herpesvirus family as homologues were found in three other human herpesviruses. The five sequences were aligned and found to be quite divergent. Some of the differences occur at amino acid positions which are functionally important and highly conserved in known protein kinases. Hence these genes may represent a significant departure from known protein kinases in terms of structure and/or function.

Amino Acid Sequence↗
PubMed1984

Cognitive performance and functional competence in coexisting dementia and depression.

Assessment was made of the impact of depression on the intelligence, memory, and functional competence of elderly community residents (aged 57-88 years) with senile dementia of the Alzheimer's type. Outpatients with either dementia (n = 21) or dementia coexisting with depression (n = 14) were given the Wechsler Adult Intelligence Scale (WAIS), Wechsler Memory Scale (WMS), and Dementia Rating Scale (DRS). No significant group differences were found for verbal IQ, performance IQ, or WMS memory quotient. Patients with coexisting dementia and depression earned significantly lower full scale IQ scores than patients with only dementia. Analysis of WAIS and WMS subtest scores and profiles revealed no difference between the two groups. Significant associations were found among the various cognitive measures and functional competence in both groups, but the patterns of these relationships differed. Intellectual measures accounted for the greatest proportion of functional competence variance in the patients with dementia, whereas memory measures accounted for the greatest proportion of variance in the patients with coexisting dementia and depression.

Aged↗
PubMed1979

Volumetric method for determing traces of organic chlorine in lipids.

The official AOAC method for determining chlorine in cake flour lipids has been modified to determine chlorine in lipids of animal carcasses cooled with chlorinated water. The sensitivity of the method has been improved 1000-fold to attain a detection limit of 2 ppm Cl in lipids. Recovery of the fine silver chloride precipitate was improved through centrifugation rather than filtration. The official method also did not take into consideration that when the silver chloride precipitate is exposed to light, it is converted to free chlorine and silver. Recovery of organic chlorine ranged from 84.6% at 4.1 ppm to 100.1% at 100 ppm. A number of samples of commercially chlorinated beef, pork, and chicken and laboratory-chlorinated chicken were analyzed by this method. In all cases where the level of chlorination was sufficient to result in a chlorine level in lipids in excess of 2 ppm, the chlorine content of the carcass lipids was measurable.

Animals↗