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E Frost

Publications and source records attributed to E Frost.

At least 37 records · Page 2Linked to original sources
PubMed1996

Comparison of polymerase chain reaction and monoclonal antibodies for G-typing of group A bovine rotavirus directly from fecal material.

A reverse transcriptase and polymerase chain reaction (RT-PCR)-based assay for G-typing of bovine rotaviruses (BRV) was compared with a monoclonal antibody-based immunoassay (MAbs-ELISA) in the characterization of BRV field strains obtained from calves in different regions of Quebec between 1992 and 1994. The strains were analysed for two G types (G6 and G10) which are the most predominate BRV field strains. Fecal samples positive for BRV by polyacrylamide gel electrophoresis (n = 74) were typed by both methods revealing 77% correlation. RT-PCR detected 10 more G6 and 2 more G10 serotypes than MAbs-ELISA. Nine of the 12 discrepant samples could be cultivated and were confirmed as G6 (8) or G10 (1) by both methods. RT-PCR was able to efficiently detect artificial mixes of G6 and G10 and detected two mixed field infections. Four additional infections considered as mixed by MAbs-ELISA and as only G6 by RT-PCR were possibly MAbs-ELISA cross-reactions. RT-PCR provided a very sensitive method for typing BRV field isolates.

Animals↗
PubMed1996

Regulation of oligodendrocyte precursor migration by extracellular matrix: evidence for substrate-specific inhibition of migration by tenascin-C.

In order to analyse the role of the extracellular matrix (ECM) in the migration of oligodendrocyte precursor cells we have used a chemotaxis chamber assay in which the filter separating the wells is coated with different ECM molecules. Two molecules, fibronectin and the laminin family member merosin, promoted migration either alone or in combination with the chemotactic growth factor platelet-derived growth factor. The effects of the ECM molecules and growth factor were additive, and demonstrated that the migrating oligodendrocyte precursors respond both to haptotactic and chemotactic stimuli. A third extracellular molecule, tenascin-C, inhibited migration. This inhibition was substrate-specific; while migration on fibronectin was inhibited there was no effect on merosin-stimulated migration. This specificity confirms that tenascin-C inhibits migration by modulation of individual cell-ECM interactions rather than by a non-specific process of interference with substrate adhesion. An understanding of the role of tenascin-C in central nervous system development will therefore require characterisation of the different colocalising ECM molecules at different developmental stages.

Animals↗
PubMed1994

Cost effectiveness of adjuvant bile salt treatment in extracorporeal shock wave lithotripsy for the treatment of gall bladder stones.

The relative cost effectiveness of adjuvant urso and chenodeoxycholic acid treatment in extracorporeal shockwave lithotripsy (ESWL) has been assessed as part of a pragmatic randomised controlled trial of ESWL as a treatment of gall bladder stones. Of the first patients with gall stone volume < 4 cm3 randomised to ESWL in the main trial, 24 were randomised to have ESWL alone and 26 to have adjuvant bile acid treatment, one of whom died before the end of the 12 month follow up period. At 12 months after treatment, differences in gall stone clearance between ESWL alone (3/24 (13%) clear, 5 (21%) referred for surgery) and ESWL and bile acids (6/25 (24%) clear, 2 (8%) referred for surgery) were not significant (p = 0.36, log rank test). Patients in both groups had substantial and significant health gains (according to biliary pain frequency and severity, Nottingham Health Profile scores, visual analogue scale symptom scores, and complications) but there were no significant differences between the groups. Improvements in both groups usually occurred within a few weeks of treatment and were unrelated to gall stone clearance. Costs were greater in the bile salt group (95% confidence intervals for estimated cost difference: 90 pounds to 630 pounds). If the purpose of treatment is symptom relief rather than gall stone clearance then adjuvant bile salt treatment seems to be unnecessary.

Adult↗
PubMed1992

Randomised controlled trial of cost-effectiveness of lithotripsy and open cholecystectomy as treatments for gallbladder stones.

Inpatient extracorporeal shockwave lithotripsy for treatment of gallbladder stones has not previously been compared with open cholecystectomy in terms of cost-effectiveness. In a randomised controlled trial, 163 patients, stratified by gallstone bulk (over 4 cm3 or not), were randomised to lithotripsy or cholecystectomy (38 large-bulk and 27 small-bulk cholecystectomy; 37 large-bulk and 61 small-bulk lithotripsy) and followed up for 1 year. Both treatments gave significant health gains in terms of a reduction in episodes of biliary pain, improved perceived health status, and symptom relief, but few differences between treatments were found. There was some evidence that biliary-pain episodes were less severe after cholecystectomy. Cholecystectomy patients also had greater improvements in mean health gain for three related symptoms: vomiting, feeling sick, and fatty-food upset. However, there were no differences between groups in perceived health status. Among lithotripsy patients, health gain was not related to stone clearance. Lithotripsy was more expensive than cholecystectomy, principally because of the costs of the inpatient stay and adjuvant bile-salt therapy. Conventional lithotripsy appears at least as cost-effective as cholecystectomy for patients with small-bulk stones but less cost-effective for those with large-bulk stones. To some extent treatment choice can be guided by patient preference.

Adult↗
PubMed1988

Infertility in Central Africa: infection is the cause.

Determinants of infertility were studied in 340 women in Eastern Gabon, an area situated in the "infertility belt" of Central Africa. Fallopian tube occlusion was diagnosed in 82.8% of cases, showing the importance of infection-related causes. Women with tubal occlusion did not differ significantly from women with normal tubes in obstetrical history or prevalence of Neisseria gonorrhoeae or Chlamydia trachomatis on endocervical culture. Antecedents of pelvic inflammatory disease or a pelvic mass were significantly more common in the group with tubal occlusion. This group also had a significantly higher prevalence of serum chlamydial antibodies at a titer of 1/64 or higher. Hormonal factors were found in 31.7% of women, a cervical factor in 29.0% and mechanical factors in 5.6%. No diagnosis could be made in 12.2% of cases. During the investigation, 4.4% of women became pregnant. The predominance of infectious related causes of infertility makes it imperative to focus resources on prevention programs of upper genital tract infections in women.

Adult↗
PubMed1988

Isolation and characterization of simian immunodeficiency virus from mandrills in Africa and its relationship to other human and simian immunodeficiency viruses.

Two isolates of simian retrovirus related to the human immunodeficiency virus (HIV) were obtained from apparently healthy mandrills, Papio (Mandrillus) sphinx, in western equatorial Africa. This virus, designated SIVMND (simian immunodeficiency virus from mandrills), appeared morphologically similar to HIV by electron microscopy, showed Mg2+-dependent reverse transcriptase activity, and induced cytopathic effect in human CD4-positive cells. Western blotting (immunoblotting) analyses revealed that the gag and pol products of SIVMND showed cross-reactivity with those of known HIVs and SIVs. Molecular clones covering full-length viral DNA were obtained from closed circular extrachromosomal DNA of SIVMND-infected cells. By clone-on-clone hybridization with known retroviruses of the HIV and SIV groups, SIVMND showed similar cross-hybridization with HIV-1, HIV-2, SIVAGM (African green monkey-derived SIV), and SIVMAC (rhesus macaque-derived SIV) in the gag and pol regions only at low stringency but not at high stringency, a result indicating that SIVMND is a new member of the HIV-SIV group. The existence of distinct SIVs in different monkey species suggest that recent interspecies transfer of HIV-SIV is unlikely in nature.

Animals↗
PubMed1988

Urogenital Chlamydia trachomatis in Gabon: an unrecognised epidemic.

Samples from 218 men with urethritis, 517 women with pelvic pain or pelvic pain and vaginal discharge, 218 women consulting for infertility, and 598 postpartal women were screened for Chlamydia trachomatis by culture and direct immunofluorescence. Chlamydiae were detected in 18% (39/218) of the men, 18% (45/252) of women with vaginal discharge, 14% (38/265) of those with pelvic pain, 10% (21/218) of infertile, and 10% (59/598) of postpartal women. A chlamydial prevalence of 18% (41) was observed in 229 postpartal women aged under 21, whereas only 5% (10) of 360 postpartal women over 21 had C trachomatis. In the other clinical groups, an age related decrease in prevalence was noted in women over 25. The direct immunofluorescence test correlated well with culture. The small difference in isolation between symptomatic and postpartal women indicates that women in this population do not seek medical attention for chlamydial infections and expose themselves to chlamydial salpingitis and infertility.

Chlamydia Infections↗
PubMed1988

[Seroprevalence of syphilis in urban and semi-rural populations of Gabon].

The seroprevalence of syphilis was studied in an urban and a semi-rural community in Gabon by a cluster sampling technique. The crude prevalence rate of treponemal infection in the semi-rural population was estimated to be 13.3 +/- 5.0% and in the urban population 19.4 +/- 4.6%. The age-adjusted prevalence rate was significantly higher in the urban than in the semi-rural population. In both areas, it was significantly higher in men than in women. No significant difference was observed according to age. These high rates indicate the need for a control program for sexually transmitted diseases.

Adolescent↗
PubMed1987

Ophthalmia neonatorum in a semi-rural African community.

The incidence and aetiology of ophthalmia neonatorum have been estimated over a 7-month period in Franceville, a semi-rural community in south-eastern Gabon. Chlamydia trachomatis was the most frequently observed pathogen, being isolated from 17 babies (2.7% of births), and Neisseria gonorrhoeae was recovered from 12 (1.6% of births). 5 of 17 cases of chlamydial conjunctivitis were in infants less than 5 d old as opposed to 9 in the typical 5 to 10-days-old group. As expected, most cases of gonococcal ophthalmia neonatorum occurred in the first 5 d of life with cases in older infants often not accompanied by a granulocytic response. Chlamydial conjunctivitis was usually unilateral whereas other cases were most frequently bilateral.

Age Factors↗
PubMed1987

Human T-cell leukemia virus type I isolates from Gabon and Ghana: comparative analysis of proviral genomes.

Two isolates of human T-cell leukemia virus type I (HTLV-I) were obtained from lymphocyte cultures of a healthy carrier in Gabon and another in Ghana. Their proviruses were analyzed by Southern blot hybridization and compared with prototypical HTLV-I isolated in Japan and the United States. The provirus genomes of both strains were highly homologous to the prototype HTLV-I along the whole viral genome. The restriction endonuclease sites of the Ghanian isolate were almost identical with those of the prototype HTLV-I, but 10 of 26 sites of the Gabonese isolate were different from those of the prototype. Furthermore, the restriction map of the Gabonese isolate resembled those of a simian T-cell leukemia virus (STLV-I) isolated from a chimpanzee from Sierra Leone and a variant of HTLV-I from Zaire (HTLV-Ib) more closely than those of any other known HTLV-I. These results indicated the existence of some unique strains of HTLV-I transmitted among African people, and the importance of clarifying the origin and transmission of HTLV group viruses.

Biological Evolution↗
PubMed1987

Importance of chlamydial antibodies in acute salpingitis in central Africa.

Of 35 women with acute salpingitis on laparoscopy, 86% had chlamydial antibodies at a titre of 1/16 or higher and 49% at a titre of 1/512 or higher. Geometric mean titres of chlamydial antibodies correlated significantly with a laparoscopic observation of chronic salpingitis (p less than 0.001), with a history of infertility (p less than 0.05), and with severe inflammation (p less than 0.10), but not with a history of salpingitis or a positive cervical culture for Chlamydia trachomatis. In the subgroup of infertile women, the geometric mean titre of antibodies to chlamydiae correlated significantly with the presence of chronic salpingitis (p less than 0.005). These data indicate that chlamydial infections play a major part in salpingitis and infertility in central Africa. In this area, which is known as the "infertility belt", programmes to control chlamydial infections should be implemented.

Acute Disease↗