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Biomedical subjects

L Forbes

Publications and source records attributed to L Forbes.

At least 19 recordsLinked to original sources
PubMed2005

Towards single screening tests for brucellosis.

This paper describes an indirect enzyme-linked immunosorbent assay (I-ELISA) and a fluorescence polarisation assay (FPA), each capable of detecting antibody in several species of hosts to smooth and rough members of the genus Brucella. The I-ELISA uses a mixture of smooth lipopolysaccharide (SLPS) and rough lipopolysaccharide (RLPS) as the antigen, and a recombinant protein A/G conjugated with horseradish peroxidase as the detection reagent. When using individually determined cutoff values, the SLPS/RLPS combined-antigen I-ELISA detected antibody in slightly more animals exposed to SLPS or to RLPS than did I-ELISA procedures using each individual antigen separately. Similarly, the assay using combined antigens detected antibody in slightly fewer animals not exposed to Brucella sp. When a universal cutoff of 10% positivity was used (relative to strongly positive control sera of each species), the overall performance index (percentage sensitivity plus percentage specificity) value decreased by 1.0 (from 199.4 to 198.4). In the FPA, it was not possible to use a universal cutoff without significant loss of performance. The overall sensitivity value for the FPA using the combined FPA antigen was 1.0% lower than using the O-polysaccharide (OPS) from SLPS and 9.1% higher than using the core antigen (CORE) from RLPS. When the combined antigen was used, the FPA specificity was slightly higher (1.2%) than from only the OPS, and considerably higher (12.6%) than the CORE. Overall, both the I-ELISA and the FPA with combined antigens were suitable as screening tests for all species of Brucella in the animal species tested.

Animal Diseases↗
PubMed2003

Laparoscopic total mesorectal excision (TME) for rectal cancer surgery: long-term outcomes.

BACKGROUND: Total mesorectal excision (TME) offers the lowest reported rates of local recurrence and the best survival results in patients with rectal cancer. However, the laparoscopic approach to resection for colorectal cancer remains controversial due to fears that oncologic principles will be compromised. We assessed the feasibility, safety and long-term outcome of laparoscopic rectal cancer resections following the principles of TME. The aim of this study was to evaluate the perioperative outcome and long-term results of laparoscopic TME. METHODS: We reviewed the prospective database of 102 consecutive unselected patients undergoing laparoscopic TME for rectal cancer between November 1991 and December 2000. Follow-up was done through office charts or direct patient contact. Recurrence and survival curves were generated by the Kaplan-Meier method. RESULTS: Laparoscopic TME was completed successfully in 99 patients, whereas conversion to an open approach was required in three cases (3%). The overall morbidity and mortality rates were 27% and 2%, respectively, with an overall anastomotic leak rate of 17%. Of the 102 patients, four were excluded from the oncologic evaluation because final pathology was not confirmatory (two had anal canal squamous cell carcinoma and two had villous adenoma with dysplasia). In 90 of the 98 remaining patients (91.8%), the resection was considered curative. The remainder had a palliative resection due to synchronous metastatic disease or locally advanced disease. Mean follow-up was 36 months (range, 6-96). There were no trocar site recurrences. The local recurrence rate was 6%, and the cancer-specific survival of all curatively resected patients was 75% at 5 years. The overall survival rate of all curatively resected patients was 65% at 5 years; mean survival time was 6.23 years (95% confidence interval [CI], 5.39-7.07). CONCLUSION: Laparoscopic TME is feasible and safe. The laparoscopic approach to the surgical treatment of operable rectal cancer does not seem to entail any oncologic disadvantages.

Adult↗
PubMed2003

Experimental Trichinella infection in seals.

The susceptibility of seals to infection with Trichinella nativa and the cold tolerant characteristics of muscle larvae in seal meat were evaluated. Two grey seals, Halichoerus grypus, were inoculated with 5000 (100 larvae/kg) T. nativa larvae and two grey seals with 50000 (1000 larvae/kg). One seal from each dose group and two control seals were killed at 5 and 10 weeks post-inoculation (p.i.). At 5 weeks p.i., infection was established in both low and high dose seals with mean larval densities of 68 and 472 larvae per gram (lpg), respectively, using eight different muscles for analyses. At 10 weeks p.i., mean larval densities were 531 and 2649 lpg, respectively, suggesting an extended persistence of intestinal worms. In seals with high larval density infections, the distribution of larvae in various muscles was uniform, but in one seal with a low larval density infection, predilection sites of larvae included muscle groups with a relative high blood flow, i.e. diaphragm, intercostal and rear flipper muscles. Trichinella-specific antibody levels, as measured by ELISA, increased during the 10 week experimental period. Infected seal muscle was stored at 5, -5 and -18 degrees C for 1, 4 and 8 weeks. Muscle larvae released from stored seal muscle by artificial digestion were inoculated into mice to assess viability and infectivity. Larvae from seal muscle 10 weeks p.i. tolerated -18 degrees C for 8 weeks but larvae from seal muscle 5 weeks p.i. tolerated only 1 week at -18 degrees C, supporting the hypothesis that freeze tolerance increases with the age of the host-parasite tissue complex. The expressed susceptibility to infection, extended production of larvae, antibody response and freeze tolerance of T. nativa in seals are new findings from the first experimental Trichinella infection in any marine mammal and suggest that pinnipeds (phocids, otariiids or walrus) may acquire Trichinella infection by scavenging even small amounts of infected tissue left by hunters or predators.

Animals↗
PubMed2003

Accident and emergency departments are still failing to assess asthma severity.

OBJECTIVES: To quantify the documentation of vital signs in children attending accident and emergency (A&E) for asthma and to assess whether indicators of severity were used appropriately. METHODS: Records of all children aged 3 to 14 attending A&E for the treatment of asthma in four London hospitals over a three month period were examined for documentation of heart rate, respiratory rate, peak expiratory flow rate, oxygen saturation, and fraction of inspired oxygen. The relation between severity indicators and whether the child was admitted or not was examined. RESULTS: There were 255 attendances in 229 children. Heart rate, respiratory rate, and oxygen saturation were recorded on most attendances (94.5%, 85.5%, and 96.8%) but fraction of inspired oxygen and peak flow were recorded in few children (48.6% and 48.5%). Heart rate and respiratory rate were higher and oxygen saturation lower in children who were admitted compared with those who were not. CONCLUSIONS: Assessment of airways obstruction is inadequate in children but when measured may be used appropriately to guide admission. There is a need for interventions to improve assessment of children attending A&E for asthma.

Adolescent↗
PubMed2003

Volcanic ash and respiratory symptoms in children on the island of Montserrat, British West Indies.

BACKGROUND: In July 1995 the volcano on the West Indian island of Montserrat erupted after being inactive for several hundred years. Since then, clouds of ash have been released intermittently from the volcano. Some of this ash is <10 micro m in diameter and therefore respirable. Concerns were raised that the particles might cause respiratory problems. AIMS: To evaluate whether ashfalls had any effect on the respiratory health of children in Montserrat. METHODS: A survey of asthma diagnoses, respiratory symptoms, exercise induced bronchoconstriction (EIB), and current and previous exposure to volcanic ash was carried out in schools in Montserrat during February 1998. RESULTS: Questionnaire information was available for nearly 80% of the 443 children on the school rolls. The prevalence of wheeze symptoms in the previous 12 months was 18% in children aged 12 years and under and 16% in children aged 13 years and over. In children aged 12 and under, the prevalence of wheeze was greater in those who had ever been heavily or moderately exposed to volcanic ash compared with the group who had only ever been exposed to low levels (wheeze in last 12 months: odds ratio (OR) 4.30; wheeze ever: OR 3.45). The prevalence of EIB in 8-12 year olds was about four times higher in those who were currently heavily exposed to volcanic ash (OR 3.85) compared to those currently exposed to low levels. CONCLUSIONS: Volcanic ash emissions adversely affected the respiratory health of Montserrat children. The findings emphasise the need to limit exposures of children to volcanic ash and ensure the appropriate management of respiratory symptoms.

Adolescent↗
PubMed2003

Performance evaluation of a new compact hematology analyzer, the Sysmex pocH-100i.

Medical practitioners are searching for ways to improve the quality and outcome of care while decreasing cost. One technological advance that may facilitate this is point-of-care testing. The pocH-100i hematology analyzer (Sysmex Corporation, Kobe, Japan) is a compact device designed specifically for point-of-care testing environments. The analyzer provides a full blood count and a 3-part differential leukocyte count. A distinct advantage is that neutrophils are reported separately, which is useful for monitoring oncology patients. The device was evaluated in accordance with International Council for Standardization in Haematology (ICSH) guidelines for precision, linearity, carryover, and effects of sample aging. The pocH-100i analyzer was compared with the Sysmex KX-21N device. The results for all parameters tested were almost identical. When samples including blast cells, immature granulocytes, and nucleated red blood cells were excluded, the pocH-100i automated differential compared well with a 400-cell manual differential. Results for neutrophils (r2 = 0.996), lymphocytes (r2 = 0.999), and the "mixed" population of cells (r2 = 0.611) indicated the pocH-100i analyzer would be highly suitable for low-volume laboratories and near-patient services.

Blood Cell Count↗
PubMed2001

Evaluation of the fluorescence polarization assay and comparison to other serological assays for detection of brucellosis in cervids.

The complement fixation test (CFT), competitive enzyme immunoassay (CELISA), indirect enzyme immunoassay (IELISA) and fluorescence polarization assay (FPA) were evaluated for the detection of antibodies to Brucella abortus and Brucella suis biotype 4 in caribou (Rangifer tarandus caribou), elk (Cervus elapus), red deer (Cervus elapus), and reindeer (Rangifer tarandus tarandus). When combining the data the FPA and the CELISA were determined to be the most suitable tests for serodiagnosis of Cervidae. The overall actual sensitivity of the CFT and the IELISA was 100%. The overall actual sensitivity for the CELISA and FPA was 99%. The overall relative specificity of the CFT (including treatment of anti-complementary data as positive or negative for analysis), the CELISA, the IELISA and the FPA were 65%, 93%, 99%, 99%, and 99%, respectively. The specificities of the buffered plate agglutination test (BPAT), the CFT, the CELISA, the FPA and the IELISA for 55 elk vaccinated with B. abortus strain 19 and tested 4 mo post vaccination were 14%, 31%, 51%, 84%, and 2%, respectively. The FPA is the diagnostic test of choice because it has sensitivity and specificity values comparable to the CELISA; it has the capability to distinguish vaccinal antibody and antibody resulting from exposure to cross-reacting organisms such as Yersinia enterocolitica 0:9 from antibody to Brucella spp. in most cases; it is technically simple to do; it is adaptable to field use and it is relatively inexpensive.

Animal Diseases↗
PubMed2000

Validation of the fluorescence polarization assay and comparison to other serological assays for the detection of serum antibodies to Brucella abortus in bison.

A number of serological tests were compared for the detection of antibodies to Brucella abortus in bison (Bison bison). The performance of the fluorescence polarization assay (FPA) in both the preliminary evaluation and a subsequent blind validation indicated that this test was the most suitable for serological diagnosis of brucellosis in bison. The sensitivity and specificity in the preliminary evaluation were 92.1% and 99.4%, respectively. The sensitivity and specificity in a subsequent blind study were 96.3% and 97.6%, respectively. In a double blind study conducted on bison vaccinated with B. abortus strain 19, the data suggests that the FPA can differentiate bison infected with B. abortus from bison vaccinated with B. abortus strain 19. Both the indirect immunoassay (IELISA) and the competitive immunoassay (CELISA) performed nearly as well as the FPA. The buffered antigen plate agglutination test (BPAT) and the complement fixation test (CFT) did not perform as well as the FPA, CELISA or the IELISA in both studies. The FPA is a homogeneous assay eliminating the washing steps and reducing incubation to minutes rather than hours saving on time, equipment, materials, reagents and cost. These attributes, together, with its excellent sensitivity and specificity make the FPA an attractive test for the detection of serum antibodies to Brucella abortus in bison.

Agglutination Tests↗
PubMed1999

Reconstitution of GTPgammaS-induced NADPH oxidase activity in streptolysin-O-permeabilized neutrophils by specific cytosol fractions.

GTPgammaS activates the NADPH oxidase and this activity declines rapidly with time after preexposure to streptolysin O. This was not due to loss of p47(phox), p67(phox), or Rac. To identify the component(s) leaking out of the permeabilized cell responsible for loss of activity, a GTPgammaS-dependent reconstitution assay was established. Neutrophil cytosol was subjected to chromatographic fractionation steps for purification of the minimum fraction required to restore activity. The reconstitution of the GTPgammaS-stimulated activity was dependent on ATP. The inhibitors staurosporine and calphostin C greatly reduced the activity in the reconstitution assay, implicating the involvement of a protein kinase C (PKC) pathway. PKC isoforms beta and delta were eliminated as the active factors in the most pure reconstitution fraction. With this novel cell-based reconstitution assay, we have identified the requirement for a protein kinase, or its substrate, for the restoration of GTPgammaS activation of the NADPH oxidase.

Bacterial Proteins↗
PubMed1999

Do hormonal contraceptives influence asthma severity?

There is some evidence that endogenous progesterone and oestrogen levels influence asthma severity in females, but little is known about the effects of hormonal contraceptives. This study aimed to describe how females with asthma perceived the effects of hormonal contraceptives on symptom severity, and to describe the association between asthma severity and current use of hormonal contraceptives. A questionnaire was sent to 891 females with asthma aged 20-30 yrs recruited from general practice registers in South London, UK. It asked about perceptions of the effects of hormonal contraceptives on asthma severity, about current use of hormonal contraceptives, and included an asthma quality of life questionnaire as a measure of asthma severity. About 6% of respondents who had ever used hormonal contraceptives reported that these had influenced asthma severity, -4% reporting worsening and 2% an improvement. There were no significant differences in asthma quality of life score between females currently taking hormonal contraceptives and those not, between those taking combined and progesterone-only preparations, or between users of different progestagen types. This study found no evidence of any important effect of hormonal contraceptives or their components on asthma severity in a group of females with relatively mild asthma.

Adult↗
PubMed1998

TCRBV14S1 and rheumatoid arthritis revisited: abnormalities in the percentage of transcribed TCRBV14S1 family genes in PBMC from rheumatoid arthritis patients.

The purpose of this study was to identify Vbeta gene families that are associated with rheumatoid arthritis (RA). A PCR-based assay was used to compare the Vbeta repertoire of unstimulated PBMC from 18 RA patients and 18 matched controls. The influence of an HLA-DRB1-binding peptide (HA307-319) on the Vbeta repertoire of PBMC in culture was compared in 11 RA patients and 10 controls. There was a larger variance in the percentage of BV14S1 transcripts in unstimulated PBMC from RA patients than from controls (p = 0.0003). The mean percentage of BV14S1 transcripts was higher in RA patients when prednisone-treated RA patients were excluded from the analysis (p = 0.0006). In vitro stimulation with the HA307-319 peptide increased the percentage of BV14S1 transcripts in PBMC from RA patients (+ 1.5 +/- 0.4%, p < 0.005) but not controls (+ 0.3 +/- 0.2%, ns), and the difference between RA patients and controls was significant (p = 0.03). In conclusion, there is an association between RA and the BV14S1 gene family in New Zealand patients.

Arthritis, Rheumatoid↗
PubMed1995

Identification of a silencer, enhancer, and basal promoter region in the human CD95 (Fas/APO-1) gene.

Genomic clones for the human CD95 (Fas/APO-1) and CD40 genes have been isolated and 2.3 kb of the CD95 and 0.8 kb of the CD40 gene 5'-flanking regions sequenced. Comparisons of the human CD95 gene with the human CD40 and the murine CD40 and TNFR-II genes showed a low degree of sequence similarity. However, dot matrix analyses revealed conservation of two stretches between human CD95 (-387 to -362 and -288 to 261 in CD95) and murine TNFR-II genes. Additionally, TCCTCC motifs are present within 400 bp up-stream of the ATG of all genes examined. Repeated interferon-beta (IFN-beta) silencer B motifs and a lysozyme silencer 1 motif have been found in the CD95 gene at approximately -1,600 and -1,100, respectively. Sequence comparison of the 5'-flanking regions of the murine and human CD40 genes revealed the presence of a conserved AP-4 site and two SP-1 sites. CD95, CD40, and TNFR-II genes all lack classical TATA and CAAT boxes. However, a strongly increased frequency of CpG dinucleotides was found. Primer extension analysis revealed multiple transcriptional start sites in the CD95 gene, where the usage of individual start sites appeared to be cell type-specific. Functional analysis, using reporter constructs and transient transfections, identified a silencer activity residing between nucleotide positions -1,781 and -1007 and a strong enhancer region between -1,007 and -425 in the human CD95 gene. The region between -425 and -1 retained a basal promoter activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗