PubMed Health⌕ Search

Biomedical subjects

A J Robinson

Publications and source records attributed to A J Robinson.

At least 73 records · Page 4Linked to original sources
PubMed1996

Comparison of the ligase chain reaction with cell culture for the diagnosis of Chlamydia trachomatis infection in women.

OBJECTIVE: To determine the sensitivity and specificity of ligase chain reaction (LCR) analysis of cervical and urine specimens from women compared with cell culture of cervical and urethral specimens for the diagnosis of genitourinary chlamydial infection. METHODS: Women (n = 624) attending the Genitourinary Medicine Clinic at University College London Hospitals, were enrolled. Patients who had received antibiotics within the previous two weeks were excluded. Specimens were obtained from the urethra and cervix for chlamydial culture, and from the cervix for LCR. A specimen of first void urine was also obtained for LCR. Discrepancies were resolved by direct immunofluorescence or a major outer membrane protein targeted LCR, or both. RESULTS: The prevalence of Chlamydia trachomatis in 600 patients, using an expanded standard of a positive cell culture or two confirmed positive non-culture tests, was 13.2% (79/600). Cervical culture detected 68.4% and urethral culture 62% of all positive results compared with 81% detected by cervical LCR and 69% by urine LCR. Cervical and urethral culture combined detected 87.3% whereas cervical and urine LCR combined detected 91.1% of positive cases. Specificity of LCR was 100% in the cervix and 99.8% in urine. CONCLUSION: This study demonstrates that LCR analysis of cervical and urine specimens is a reliable method for the diagnosis of chlamydial genital infection in women. However, the study also demonstrates that no single test will detect all chlamydial infections. Conventional non-culture tests and cell culture may grossly underestimate the prevalence of chlamydial infection. LCR analysis of a cervical specimen was superior to conventional cell culture without blind passage as a single test for diagnosing chlamydial infection in women, followed by LCR of a urine specimen.

Cell Culture Techniques↗
PubMed1996

Transcutaneous electrical nerve stimulation for the control of pain in musculoskeletal disorders.

The literature on the use of transcutaneous electrical nerve stimulation (TENS) for pain control in several common musculoskeletal disorders is reviewed. The need for this review stems from apparently contradictory results of numerous studies designed to address the efficacy of electrical stimulation procedures for pain control. The focus of the review is on the efficacy of TENS in the management of low back pain syndromes. Other areas discussed include TENS use in arthritic conditions, soft tissue inflammatory disorders, and in postoperative pain following orthopaedic surgical procedures. Methodological strengths and weaknesses of TENS studies are emphasized in order to assist the reader in understanding the relative value of TENS studies which either support or refute the efficacy of electrical stimulation procedures for pain control.

Forecasting↗
PubMed1995

Parapoxvirus of red deer: evidence for its inclusion as a new member in the genus parapoxvirus.

There are three accepted members of the parapoxvirus genus, orf virus (OV), papular stomatitis virus (PSV), and pseudocowpox virus (PCV). OV is maintained in sheep and goats and PSV and PCV in cattle. Restriction endonuclease profiles of the DNA derived from representatives of these established members of the genus were compared with profiles from a parapoxvirus recently isolated from red deer. In no case did the profile of this latter virus (DPV) resemble those generated from the other parapoxviruses. Southern blot hybridization using total DPV DNA as a probe revealed homology between DPV and the central regions of the genomes of the other parapoxviruses but not to their terminal regions. These results indicate that the genome of DPV is as different from the genomes of the three accepted members of the genus as the latter are from each other and argue for the inclusion of DPV as a new member of the parapoxvirus genus.

Animals↗
PubMed1995

Identification and characterization of the orf virus type I topoisomerase.

Vaccinia virus (VV) and Shope fibroma virus (SFV), representatives of the orthopox and leporipox genera, respectively, encode type I DNA topoisomerases. Here we report that the 957-nt F4R open reading frame of orf virus (OV), a representative of the parapox genus, is predicted to encode a 318-aa protein with extensive homology to these enzymes. The deduced amino acid sequence of F4R has 54.7 and 50.6% identity with the VV and SFV enzymes, respectively. One hundred forty amino acids are predicted to be conserved in all three proteins. The F4R protein was expressed in Escherichia coli under the control of an inducible T7 promoter, partially purified, and shown to be a bona fide type I topoisomerase. Like the VV enzyme, the OV enzyme relaxed negatively supercoiled DNA in the absence of divalent cations or ATP and formed a transient covalent intermediate with cleaved DNA that could be visualized by SDS-PAGE. Both the noncovalent and covalent protein/DNA complexes could be detected in an electrophoretic mobility shift assay. The initial PCR used to prepare expression constructs yielded a mutant allele of the OV topoisomerase with a G-A transition at nt 677 that was predicted to replace a highly conserved Tyr residue with a Cys. This allele directed the expression of an enzyme which retained noncovalent DNA binding activity but was severely impaired in DNA cleavage and relaxation. Incubation of pUC19 DNA with the wild-type OV or VV enzyme yielded an indistinguishable set of DNA cleavage fragments, although the relative abundance of the fragments differed for the two enzymes. Using a duplex oligonucleotide substrate containing the consensus site for the VV enzyme, we demonstrated that the OV enzyme also cleaved efficiently immediately downstream of the sequence CCCTT.

Amino Acid Sequence↗
PubMed1995

Sequence and transcriptional analysis of a near-terminal region of the orf virus genome.

A 3605 bp region located approximately 6.6 kb from the left end of the orf virus genome (strain NZ2) was sequenced. The sequence revealed two open reading frames, which we have designated G2L and B1L. The predicted amino acid sequences of G2L and B1L were found to be homologous to the vaccinia virus (VAC) F11L and F12L gene products, respectively, and were found to be arranged on the genome in the same orientation and relative position as their VAC counterparts. Transcriptional analysis of both G2L and B1L showed they were transcribed toward the genome terminus during the early phase of infection. S1 nuclease and primer-extension analyses showed that the transcriptional start sites of both genes were located a short distance downstream from A+T-rich sequences, similar to vac virus early promoters.

Amino Acid Sequence↗
PubMed1995

Sequence and transcriptional analysis of an orf virus gene encoding ankyrin-like repeat sequences.

A 1608 bp region located approximately 5.0 kb from the left end of the orf virus (OV) genome (strain NZ2) was sequenced. The sequence revealed a single open reading frame designated G1L. The predicted amino acid sequence of G1L contained eight ankyrinlike repeat sequences. Transcriptional analysis of G1L showed it was transcribed towards the genome terminus during the early phase of infection. S1 nuclease and primer extension analyses showed that the transcriptional start site of the gene was located a short distance downstream from an A + T-rich sequence similar to a vaccinia virus early promoter.

Amino Acid Sequence↗
PubMed1995

Behavior of cholesterol and its effect on head group and chain conformations in lipid bilayers: a molecular dynamics study.

Cholesterol molecules were put into a computer-modeled hydrated bilayer of dimyristoyl phosphatidyl choline molecules, and molecular dynamics simulations were run to characterize the effect of this important molecule on membrane structure and dynamics. The effect was judged by observing differences in order parameters, tilt angles, and the fraction of gauche bonds along the hydrocarbon chains between lipids adjacent to cholesterol molecules and comparing them with those further away. It was observed that cholesterol causes an increase in the fraction of trans dihedrals and motional ordering of chains close to the rigid steroid ring system with a decrease in the kink population. The hydrogen-bonding interactions between cholesterol and lipid molecules were determined from radial distribution calculations and showed the cholesterol hydroxyl groups either solvated by water, or forming hydrogen bond contacts with the oxygens of lipid carbonyl and phosphate groups. The dynamics and conformation of the cholesterol molecules were investigated and it was seen that they had a smaller tilt with respect to the bilayer normal than the lipid chains and furthermore that the hydrocarbon tail of the cholesterol was conformationally flexible.

Biophysical Phenomena↗
PubMed1995

Physical therapist assistants' perceptions of the documented roles of the physical therapist assistant.

BACKGROUND AND PURPOSE: This study investigated physical therapist assistants' (PTAs) perceptions of the documented roles of PTAs and compared those perceptions with those of physical therapists from a previous study. SUBJECTS AND METHODS: A questionnaire that described 79 physical therapy activities was distributed to a sample (n = 400) of PTAs derived from the American Physical Therapy Association membership. The response rate was 56% (n = 225). Respondents indicated whether each activity was included in the documentation describing PTA roles. Discriminant analyses were used to determine whether demographic factors predicted the pattern of responses. In addition, meta-analytic techniques were used to determine whether PTA responses were different from those of physical therapists gathered previously. RESULTS: The greatest agreement of PTA opinions with published guidelines occurred for treatment implementation activities, and the lowest level of agreement occurred for items designated as administrative activities. Responses of PTAs were different from those of physical therapists on 21 of the 79 activities. The greatest number of these differences occurred for evaluative functions (n = 9). Physical therapist assistants' perceptions of documented PTA roles were generally less consistent with published guidelines than were those of physical therapists. CONCLUSION AND DISCUSSION: Physical therapist assistants' perceptions of the roles of the PTA were, for some activities, not consistent with written guidelines. Using the data provided in this study, discussions to revise the documentation of the scope of PTA practice may focus on those activities for which disagreement between PTAs and physical therapists exists and for which opinions differ markedly from published guidelines. [Robinson AJ, DePalma MT, McCall M. Physical therapist assistants' perceptions of the documented roles of the physical therapist assistant.

Allied Health Personnel↗
PubMed1995

Genomic analysis of a transposition-deletion variant of orf virus reveals a 3.3 kbp region of non-essential DNA.

Restriction endonuclease analysis of the DNA extracted orf virus strain NZ2, which had been serially passaged in primary bovine testis cells, revealed a population of variants that had over-grown the wild-type virus. At least three distinct mutant forms were identified in which the right end of the genome had been duplicated and translocated to the left end, accompanied by deletions of sequences at the left end. Sequencing of a single variant isolated from the heterogeneous population revealed that recombination had occurred between non-homologous sequences. In this case, 6.6 kb of DNA at the left end of the genome had been replaced by 19.3 kb from the right end. The transposition resulted in the deletion at the left end of 3.3 kb of DNA encoding three genes and the terminal sequences of a fourth gene. The three genes completely deleted were a homologue of dUTPase, a gene that encodes a protein containing ankyrin-like repeats and a homologue of the 5K gene of the vaccinia virus WR strain. Experimental inoculation of sheep showed that the genes are also non-essential in vivo, but that the size of the lesion was reduced, compared with that induced by the wild-type, and resolved more rapidly.

Animals↗
PubMed1995

Testing the concept of virally vectored immunosterilisation for the control of wild rabbit and fox populations in Australia.

Virally vectored immunosterilisation is a concept whereby a gene encoding an antigen from an animal's reproductive system is inserted into a virus and, during infection, stimulates the formation of antibodies to that antigen such that the animal is rendered infertile. There is good evidence that certain proteins from sperm or egg when introduced parenterally will induce infertility. This paper summarises the work of the Cooperative Research Centre for the Biological Control of Vertebrate Pest Populations and reviews progress toward the isolation of the genes for gamete antigens from rabbits and foxes and their introduction into suitable viral vectors as a means of control of these pests in Australia.

Animals↗
PubMed1994

Lack of cross-protection between vaccinia virus and orf virus in hysterectomy-procured, barrier-maintained lambs.

Hysterectomy-procured, barrier maintained lambs were immunised with either of virus or vaccinia virus and subsequently challenged with both viruses. Under these conditions lambs were protected from challenge with the homologous virus but no cross-protection was observed. The feeding of colostrum that contained antibodies to orf virus had no effect on the duration of viral lesions. Immunoblotting analysis and ELISA of serum samples taken during the course of the experiment indicated that the animals mounted antibody responses to both viruses. The cross recognition of 3 vaccinia virus antigens by the hyperimmune anti-orf virus serum was revealed by immunoblotting.

Animals↗
PubMed1994

Identification and characterization of an orf virus homologue of the vaccinia virus gene encoding the major envelope antigen p37K.

DNA sequence analysis of a 1.55-kb region located 10 kb from the left end of the orf virus NZ-2 strain (OV NZ2) genome revealed an open reading frame, B2L, encoding a protein with a predicted molecular weight of 41.67 kDa. This protein (p42K) shows 42% amino acid sequence identity to the vaccinia virus (VAC) major envelope antigen p37K. In addition, p42K shows homology to a protein encoded by molluscum contagiosum virus (42.8% identity) and another encoded by fowlpox virus (38.3% identity). These proteins are themselves homologues of the VAC p37K. B2L is actively transcribed after the onset of DNA replication and S1 nuclease analysis mapped the 5' end of the transcript to within the sequence TAAATG. A VAC recombinant capable of expressing the p42K gene was constructed and used as an antigen in radioimmune precipitations and lymphocyte transformation assays. These assays demonstrated that OV p42K is one of a limited number of OV proteins to which sheep mount a strong antibody response and which stimulate lymphocytes derived from draining lymph nodes following a natural infection with OV NZ2.

Amino Acid Sequence↗
PubMed1994

Head group and chain behavior in biological membranes: a molecular dynamics computer simulation.

A computer-modeled hydrated bilayer model of the lipid 2,3-dimyristoyl-D-glycero-1-phosphorylcholine in the L alpha phase was built. Particular care was taken in building the starting structure with the inclusion of structural detail reported in experiments on the L alpha phase. Molecular dynamics simulations using the molecular dynamics and energy refinement program AMBER 3.1 force field with an optimized parameters for liquid simulation parameter set were run to study the motions and conformations of the lipid molecules and characterize the behavior and structure of the head groups and the hydrocarbon lipid chains. Although the head groups were observed to show great flexibility, certain head-group torsion combinations appeared favored. The observed tilt of the lipid chains is discussed and is consistent with previous experimental findings. Motion of the lipid chains is shown to be correlated with those chains immediately surrounding, but correlation with chains more distant varies with time.

Biophysical Phenomena↗
PubMed1994

Physical therapists' perceptions of the roles of the physical therapist assistant.

BACKGROUND AND PURPOSE: This longitudinal study investigated physical therapists' perceptions of the roles of physical therapist assistants (PTAs). METHODS AND SUBJECTS: In 1986, a questionnaire describing 79 physical therapy activities was distributed to a random sample (n = 400) of physical therapists derived from the American Physical Therapy Association (APTA) membership. In 1992, a similar questionnaire was distributed to a representative sample (n = 400) of physical therapists derived from the APTA membership. Response rates were 53% and 55% in 1986 and 1992, respectively. Respondents indicated whether each activity was included in the documentation describing PTA roles. RESULTS: Results revealed considerable agreement between therapists' perceptions of PTA roles and those outlined by PTA practice guidelines, and these perceptions changed little over time. Discriminant analyses suggested that therapists' perceptions of PTA roles were, in general, not predicted by supervisory experience with PTAs, therapist experience, or content of entry-level professional education curricula. CONCLUSION AND DISCUSSION: Generally, therapists' perceptions of PTA roles are consistent with published practice guidelines. Therapists' perceptions on selected activities, however, were incongruent with PTA practice guidelines, suggesting the potential for inefficient or inappropriate utilization of the PTA in the delivery of selected services.

Allied Health Personnel↗
PubMed1994

Homologs of vascular endothelial growth factor are encoded by the poxvirus orf virus.

A gene encoding a polypeptide with homology to mammalian vascular endothelial growth factors (VEGFs) has been discovered in the genome of orf virus (OV), a parapoxvirus that affects sheep and goats and, occasionally, humans. The gene is transcribed abundantly early in infection and is found immediately outside the inverted terminal repeat at the right end of the genome. In the NZ2 strain of OV (OV NZ2), the gene encodes a polypeptide with a molecular size of 14.7 kDa, while in another strain, OV NZ7, there is a variant gene that encodes a polypeptide of 16 kDa. The OV NZ2 and OV NZ7 polypeptides show 22 to 27% and 16 to 23% identity, respectively, to the mammalian VEGFs. The viral polypeptides are only 41.1% identical to each other, and there is little homology between the two genes at the nucleotide level. Another unusual feature of these genes is their G+C content, particularly that of OV NZ7. In a genome that is otherwise 63% G+C, the OV NZ2 gene is 57.2% G+C and the OV NZ7 gene is 39.7% G+C. The OV NZ2 gene, but not the OV NZ7 gene, is homologous to the mammalian VEGF genes at the DNA level, suggesting that the gene has been acquired from a mammalian host and is undergoing genetic drift. The lesions induced in sheep and humans after infection with OV show extensive dermal vascular endothelial proliferation and dilatation, and it is likely that this is a direct effect of the expression of the VEGF-like gene.

Amino Acid Sequence↗