Biomedical subjects

K Richmond

Publications and source records attributed to K Richmond.

15 recordsLinked to original sources

PubMed2006

Diagnostic accuracy of a point-of-care syphilis test when used among pregnant women in Bolivia.

OBJECTIVE: To evaluate the performance of a point-of-care (POC) syphilis test when used in urban Bolivian maternity hospitals. METHODS: We tested 8892 pregnant women for syphilis using the Abbott Determine Syphilis TP rapid POC test and rapid plasma reagin (RPR) in the laboratory of four large urban maternity hospitals where national statistics reported a syphilis prevalence of at least 3%. Sera were stored and transferred to the national reference laboratory (INLASA) where RPR testing was repeated. When the reference laboratory staff observed a positive RPR result, a Treponema pallidum particle agglutination assay (TPPA) was performed to confirm these findings. We calculated test performance characteristics for the POC test and hospital RPR using RPR performed at the reference laboratory confirmed by TPPA as the reference standard. Participants received treatment during their initial visit based on the POC test results. RESULTS: The sensitivity, specificity, negative predictive value and positive predictive values of the POC syphilis test were: 91.8% (95% confidence intervals 88.4% to 94.5%), 98.5% (98.2% to 98.8%), 71.0% (66.6% to 75.2%), and 99.7% (99.5% to 99.8%), respectively. The RPR values were 75.7% (70.8% to 80.2%), 99.0% (98.9% to 99.3%), 76.9% (72.0% to 81.3%), and 99.0% (98.8% to 99.2%), respectively. CONCLUSION: The Abbott Determine Syphilis TP test proved to be more sensitive than routine RPR and had comparable specificity. POC testing may be a simple way to expand syphilis screening to clinics with no laboratory facilities, improve case detection, and facilitate treatment delivery.

Adolescent↗

PubMed2004

Retrospective characterization of Newcastle Disease Virus Antrim '73 in relation to other epidemics, past and present.

In November 1973 Newcastle disease suddenly appeared in Northern Ireland, where the viscerotropic disease had not been seen in 3 1/2 years and the two Irelands had been regarded as largely disease free for 30 years. It was successfully controlled with only 36 confirmed affected layer flocks, plus 10 more slaughtered as 'dangerous contacts'. Contemporary investigations failed to reveal the source of the Irish epidemic. Using archival virus samples from most of the affected flocks, RT PCR was conducted with primers selected for all six NDV genes. Phylogenetic analyses of three genes, HN, M and F, confirmed vaccine as the cause of one of the outbreaks. The other six samples were identical and closely related to previous outbreaks in the United States and western Europe initiated by infected imported Latin American parrots. The probable cause of the epidemic followed from the importation from The Netherlands of bulk feed grains contaminated with infected pigeon faeces.

HN Protein↗

PubMed2001

Oligomeric structures of poliovirus polymerase are important for function.

Central to the replication of poliovirus and other positive-strand RNA viruses is the virally encoded RNA-dependent RNA polymerase. Previous biochemical studies have suggested that direct polymerase- polymerase interactions might be important for polymerase function, and the structure of poliovirus polymerase has revealed two regions of extensive polymerase-polymerase interaction. To explore potential functional roles for the structurally observed polymerase-polymerase interactions, we have performed RNA binding and extension studies of mutant polymerase proteins in solution, disulfide cross-linking studies, mutational analyses in cells, in vitro activity analyses and RNA substrate modeling studies. The results of these studies indicate that both regions of polymerase-polymerase interaction observed in the crystals are indeed functionally important and, furthermore, reveal specific functional roles for each. One of the two regions of interaction provides for efficient substrate RNA binding and the second is crucial for forming catalytic sites. These studies strongly support the hypothesis that the polymerase- polymerase interactions discovered in the crystal structure provide an exquisitely detailed structural context for poliovirus polymerase function and for poliovirus RNA replication in cells.

Amino Acid Substitution↗

PubMed1997

Molecular evolution and diversity in Bacillus anthracis as detected by amplified fragment length polymorphism markers.

Bacillus anthracis causes anthrax and represents one of the most molecularly monomorphic bacteria known. We have used AFLP (amplified fragment length polymorphism) DNA markers to analyze 78 B. anthracis isolates and six related Bacillus species for molecular variation. AFLP markers are extremely sensitive to even small sequence variation, using PCR and high-resolution electrophoresis to examine restriction fragments. Using this approach, we examined ca. 6.3% of the Bacillus genome for length mutations and ca. 0.36% for point mutations. Extensive variation was observed among taxa, and both cladistic and phenetic analyses were used to construct a phylogeny of B. anthracis and its closest relatives. This genome-wide analysis of 357 AFLP characters (polymorphic fragments) indicates that B. cereus and B. thuringiensis are the closest taxa to B. anthracis, with B. mycoides slightly more distant. B. subtilis, B. polymyxa, and B. stearothermophilus shared few AFLP markers with B. anthracis and were used as outgroups to root the analysis. In contrast to the variation among taxa, only rare AFLP marker variation was observed within B. anthracis, which may be the most genetically uniform bacterial species known. However, AFLP markers did establish the presence or absence of the pXO1 and pXO2 plasmids and detected 31 polymorphic chromosomal regions among the 79 B. anthracis isolates. Cluster analysis identified two very distinct genetic lineages among the B. anthracis isolates. The level of variation and its geographic distribution are consistent with a historically recent African origin for this pathogenic organism. Based on AFLP marker similarity, the ongoing anthrax epidemic in Canada and the northern United States is due to a single strain introduction that has remained stable over at least 30 years and a 1,000-mile distribution.

Animals↗

PubMed1995

Cloning of a human insulin-stimulated protein kinase (ISPK-1) gene and analysis of coding regions and mRNA levels of the ISPK-1 and the protein phosphatase-1 genes in muscle from NIDDM patients.

Complementary DNA encoding three catalytic subunits of protein phosphatase 1 (PP1 alpha, PP1 beta, and PP1 gamma) and the insulin-stimulated protein kinase 1 (ISPK-1) was analyzed for variations in the coding regions related to insulin-resistant glycogen synthesis in skeletal muscle of 30 patients with non-insulin-dependent diabetes mellitus (NIDDM). The human ISPK-1 cDNA was cloned from T-cell leukemia and placental cDNA libraries and mapped to the short arm of the human X chromosome. Single-strand conformation polymorphism (SSCP) analysis identified a total of six variations in the coding regions of the PP1 genes: two in PP1 alpha at codons 90 and 255; one in PP1 beta at codon 67; and three in PP1 gamma at codons 11,269, and 273, respectively. All were, however, silent single nucleotide substitutions. SSCP analysis of the ISPK-1 gene identified one silent polymorphism at codon 266 and one amino acid variant at codon 38 (Ile-->Ser). This variant was primarily found in one male NIDDM patient. This subject, however, did not exhibit an impairment of muscle insulin-stimulated glycogen synthase activation. No significant differences were found in mRNA levels in muscle of the four genes between 15 NIDDM patients and 14 healthy subjects. Our findings suggest that 1) genetic abnormalities in the coding regions of PP1 alpha, PP1 beta, PP1 gamma, and ISPK-1 are unlikely to be frequently occurring causes of the reduced insulin-stimulated activation of the glycogen synthesis in muscle from the analyzed group of NIDDM patients; 2) the mRNA levels of PP1 alpha, PP1 beta, PP1 gamma, and ISPK-1 are normal in muscle from the NIDDM patients; and 3) putative inherited defects in insulin-stimulated activation of muscle glycogen synthesis in patients with insulin-resistant NIDDM may be located further upstream of ISPK-1 in the insulin action cascade.

Amino Acid Sequence↗

PubMed1991

Sodium dodecyl sulphate polyacrylamide gel electrophoresis patterns of proteinuria in various renal diseases of childhood.

This study examined the potential of an automated electrophoretic system (PHASTSYSTEM, Pharmacia. Uppsala, Sweden) to distinguish patterns of proteinuria in children with various renal diseases. It proved possible to produce ready-to-read sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS PAGE) separation of 1 microliter of unconcentrated urine in 2 h. Glomerular, tubular and mixed patterns of proteinuria were identified. Steroid-responsive nephrotic syndrome (SRNS) was readily identified by strong bands of albumin and transferrin during relapses. In contrast, steroid-resistant nephrotic syndrome was associated with two additional bands of haptoglobin and IgG. Albumin dimers (Mr 120 kDa) were found in the active phase of the disease in the urine of 90% of children with SRNS. Patterns of tubular proteinuria were found in children with proximal renal tubular abnormalities. The presence of mixed patterns of glomerular and tubular proteinuria strongly suggest renal insufficiency. SDS PAGE electrophoresis can readily be applied in clinical practice. It may prove helpful in the diagnosis and management of children with renal diseases enabling correlation to be made between proteinuria, renal pathology and prognosis.

Adolescent↗

PubMed1988

Shifts in pelvic inclination angle and parasympathetic tone produced by Rolfing soft tissue manipulation.

The effects of soft tissue manipulation (Rolfing method) were evaluated on young healthy men using two dependent variables: 1) angle of pelvic inclination and 2) parasympathetic activity. Pelvic inclination was assessed by determining the angle of standing pelvic tilt (SPT) with an inclinometer. Autonomic tone was assessed by a measure of cardiac vagal tone (amplitude of respiratory sinus arrhythmia) derived from monitoring heart rate. Thirty-two subjects, preselected for exhibiting an anteriorly tilted pelvis, were randomly assigned to either an Experimental Group (n = 16) that received a 45-minute Rolfing pelvic mobilization session or a Control Group (n = 16) that received a 45-minute control session without manipulation. Dependent variables were assessed before the 45-minute session, immediately after the session, and 24 hours later. Comparing pretest to posttest assessments, the Experimental Group demonstrated a significant decrease in SPT angle and a significant increase in vagal tone. The Control Group did not show significant pretest or posttest differences. The results provide theoretical support for the reported clinical uses of soft tissue pelvic manipulation for 1) certain types of low back dysfunction and 2) musculoskeletal disorders associated with autonomic stress.

Adult↗

PubMed1979