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Biomedical subjects

R Wall

Publications and source records attributed to R Wall.

At least 91 records · Page 5Linked to original sources
PubMed1997

HIV-testing study of immigrants with pulmonary tuberculosis.

The increasing prevalence of tuberculosis (TB) and human immunodeficiency virus (HIV), particularly in Africa and Asia, led us to investigate the prevalence of HIV infection in immigrants with pulmonary TB at the time of arrival in the UK. We performed anonymous HIV testing of stored sera from 39/65 immigrants referred to our unit between January 1991 and December 1994, who had culture-positive pulmonary TB. None of the 39 patients tested was positive for either HIV-1 or HIV-2, and the characteristics of the 26 patients for whom no serum was available were similar to those of the tested group. Despite the need to consider concomitant HIV infection in any patient with TB, particularly those from an area of HIV endemnicity, the present data do not suggest that recently arrived refugees, asylum seekers, immigrants or long-term visitors to the UK constitute a group in whom dual infection of HIV and Mycobacterium tuberculosis is common.

AIDS Serodiagnosis↗
PubMed1996

A promoter ISRE and dual 5' YY1 motifs control IFN-gamma induction of the IRG-47 G-protein gene.

The IRG-47 gene is the prototype for a new family of genes encoding guanine nucleotide binding proteins (G-proteins) which are selectively induced in different cell lineages in response to activation signals. The IRG-47 gene is rapidly and transiently induced by interferon-gamma (IFN-gamma) in cells of the B lymphocyte lineage and in stromal cells and fibroblasts. Here we report features controlling the uninduced and IFN-gamma-induced expression of the IRG-47 gene. The minimal IFN-gamma-inducible IRG-47 gene promoter is 96 bp long and contains a TATA box and an ISRE motif with an internal IRF-1/IRF-2 motif. Mutation of the ISRE motif abolishes IFN-gamma induction by the minimal promoter. Constitutively expressed IRF-2 and IFN-gamma-induced IRF-1 factors specifically bind to the wild-type, but not the mutated ISRE motif. An upstream region containing two tandemly repeated YY1 motifs represses the expression of the IRG-47 promoter in uninduced cells and determines the magnitude of IRG-47 promoter activity in IFN-gamma-induced cells. The IRG-47 minimal promoter has the same functional features and organization as the IFN-gamma-inducible promoters of the unrelated murine GBP G-protein multigene family.

Animals↗
PubMed1996

Species, sub-species and hybrid populations of the blowflies Lucilia cuprina and Lucilia sericata (Diptera:Calliphoridae).

The blowflies Lucilia cuprina Wiedmann and Lucilia sericata Meigen (Diptera:Calliphoridae) are facultative ectoparasites of warm blooded vertebrates, particularly domestic sheep. Despite being similar in morphology and ecology, the two species and different populations of each species, are known to vary in their importance as pests in different regions of the world. To elucidate the genetic basis of these species and population level differences, flies were collected from sites in Africa, Europe, Australasia, North America and the islands of Hawaii, and examined using a combination of morphology, the random amplified polymorphic DNA technique and a complementary mitochondrial DNA analysis. The results confirm the species integrity of L. sericata and L. cuprina and support the existence of intra-specific genetic variation in L. cuprina, but not L. sericata.

Animals↗
PubMed1996

IFN-gamma induces the kappa intron enhancer via an IFN-stimulated response element.

IFN-gamma is a potent inducer of Ig kappa light chain gene transcription in 70Z/3 pre-B cells, but the mechanism of this induction has not been elucidated. The kappa intron enhancer contains a sequence closely resembling the IFN-stimulated response element (ISRE). We have determined that the kappa intron enhancer is IFN-gamma inducible in 70Z/3 cells and that the ISRE is required for this induction. The kappa intron ISRE specifically bound IFN response factor-1 (IRF-1) and the constitutively expressed IRF-2. This ISRE is a multifunctional motif that also binds the LPS-inducible factor kappaBF-A and is located within the kappaBS region, which confers B cell specific activity to this enhancer. However, since the expression of IRF-1 is not restricted to B cells, it must not be sufficient for the induction of kappa transcription. Furthermore, in the pre-B cell line 38B9, which is representative of an earlier stage in pre-B cell development than the 70Z/3 cell line, the kappa intron enhancer was not induced by IFN-gamma despite the activation of IRF-1. These findings suggest that IFN-gamma activation of kappa gene transcription during B cell maturation may be developmentally controlled by elements that restrict the activity of the ISRE within the context of the intron enhancer.

Animals↗
PubMed1996

Alternatively spliced exons encode the tissue-specific 5' termini of leukocyte pp52 and stromal cell S37 mRNA isoforms.

The pp52 gene encodes an intracellular, F-actin-binding phosphoprotein (also designated LSP1 and WP34) postulated to function in cytoskeleton dynamics and cell motility. We previously reported that different mRNA isoforms are expressed from this gene in cells of the leukocyte lineage versus mesodermally derived cells. These tissue-specific mRNA isoforms are identical except for 5'-untranslated regions and sequences coding for unique N-termini of 23 and 21 amino acids, respectively. As this is a single-copy gene, we predicted that these tissue-specific mRNA isoforms would be generated by alternative RNA splicing. We report that the unique 5' sequences in these mRNA isoforms are encoded in two separate exons containing ATG initiation codons. These features confirm that the pp52 and S37 mRNA isoforms are generated by alternative RNA splicing and establish that they are independently translated. Other results presented here indicate that the differential expression of these exons in leukocytes versus mesodermally derived cells is regulated at the level of transcription by tissue-specific promoters.

Alternative Splicing↗
PubMed1996

The promoter and 5' flanking sequences controlling human B29 gene expression.

The product of the B-cell-specific B29 gene (B29, Ig beta, CD79b) is essential for Ig-mediated B-cell activation via the B-cell antigen receptor complex (BCR) on human and murine B lymphocytes. To better understand the regulation of this pivotal gene, we have analyzed the human genomic DNA sequence upstream of the B29 ATG start codon for transcriptional control activity. The human B29 gene lacks either a TATA or a CAAT box and transcription is initiated at multiple sites. The minimal promoter of the human B29 gene is contained within a 193-bp region 5' of these multiple start sites. This minimal promoter exhibits B-cell-specific activity and contains SP1, ETS, OCT, and IKAROS/LYF-1 transcription factor motifs. All these motifs are strikingly conserved in sequence and placement relative to the previously characterized murine B29 promoter. Additional upstream gene segments dramatically affected B29 minimal promoter activity. A newly identified motif called the B29 conserved sequence (BCS), found upstream of both human and murine B29 promoters, appears to stimulate B29 transcription through a novel mechanism. A single BCS had little effect either on the minimal B29 promoter or on a heterologous promoter. Instead, the BCS stimulated transcription by counteracting 5' negative regulatory DNA sequences that block the activity of the B29 minimal promoter in its absence. These findings indicate that B29 gene expression is controlled by the complex interplay of positive and negative regulatory elements.

Amino Acid Sequence↗
PubMed1996

The effect of faecally excreted ivermectin and fenbendazole on the insect colonisation of cattle dung following the oral administration of sustained-release boluses.

The effects of faecal drug residues following the administration of anthelmintics in the form of sustained-release boluses, on dung-colonising Coleoptera and Diptera are reported. In blind field trials, pats of standard weight and size were prepared from the dung of cattle treated with an ivermectin (Ivomec SR Bolus, MSD Agvet) or a fenbendazole (Panacur Bolus, Hoechst) sustained-release bolus, and from a third control group of cattle that received no treatment. Pats were recovered after 7, 14, 21 and 42 days in the field and searched for invertebrates. There were no differences in the numbers of adult beetles found in the pats from the three treatment groups. Pats made from the dung of ivermectin-treated animals contained no larval Diptera Cyclorrhapha and significantly fewer larval Scarabaeidae than pats made from the dung of the other two groups. Furthermore, larval Scarabaeidae in the ivermectin pats were inhibited in their development. The pats from fenbendazole-treated animals contained similar numbers of larval Scarabaeidae and Diptera to the pats from untreated animals throughout the trial. At 42 days, the solid matter of the control and fenbendazole-containing cow pats were reduced to a crumbling, granular texture, while the pats from the ivermectin-treated animals were solid and compacted. Pitfall trapping, using traps baited with dung from the three groups, showed no significant difference between the numbers of adult Scarabaeidae attracted, though a trend towards higher numbers attracted to the dung of both anthelmintic-treated groups was evident. The results provide evidence of the toxic effects of excreted ivermectin on key dung-colonising families of insects, and show that fenbendazole lacks such toxic effects.

Administration, Oral↗
PubMed1996

Colour discrimination by the sheep blowfly Lucilia sericata.

In laboratory trials designed to examine the alighting response of the blowfly Lucilia sericata Meigen to colour, yellow sticky cloth targets caught the largest number of both males and females, followed by pale blue, black, green, dark blue and red. The number caught by any colour showed a strong positive relationship with the percentage of its spectral reflectivity in the 450-580 nm wavelength band. In field trials, targets baited with the synthetic attractant "swormlure' caught significantly fewer L.sericata than targets baited with liver and sodium sulphide, suggesting that the former bait is a relatively poor attractant for this species, at the release rates used in the present study. However, there was no effect of target colour on catch, neither was there any interaction between colour and odour bait type. The results, from both the laboratory and field trials, suggest that the strength of responses by L.sericata to visual cues are weak relative to responses to odour. Responses to hue are readily overridden by a range of factors such as brightness and contrast with the background and are therefore likely to be difficult to detect or manipulate reliably in trapping systems in the field.

Animals↗
PubMed1996

Epidemiology of gonococcal and chlamydial infections in Harrow and Brent.

OBJECTIVE: To describe the epidemiology and associated clinical features of gonorrhoea and chlamydial infection and to develop a profile of sexually transmitted diseases (STDs) in an outer London health district. DESIGN: Hospital-based retrospective study. SETTING: Genitourinary medicine clinic, Northwick Park Hospital, Harrow and Brent Health Authority. SUBJECTS: 70 male and female individuals with gonorrhoea and 129 with chlamydial infection, diagnosed consecutively over 28 months in 1992-94. RESULTS: More men than women had gonorrhoea (43 versus 27) but more women than men had chlamydial infection (84 versus 45), p < 0.001. There was a clear tendency for cases with either infection to locate along major road and rail transport routes. Foci of gonococcal infection were concentrated mainly in the densely populated areas, whereas chlamydial cases were more evenly spread. There was no significant effect of gender or type of STD on the odds ratio for residence in Harrow, single marital status or attendance for test of cure. However, the odds ratios for women having sexual intercourse with a regular partner only or previous STD were 5 (95% CI 2.4 to 10.2), p < 0.001 and 0.3 (95% CI 0.18 to 0.69), p = 0.002 times the odds for men, respectively. The odds ratios for patients with gonococcal infection being employed or having sex with a regular partner only were 0.5 (95% CI 0.27 to 0.98), p = 0.04 and 0.30 (95% CI 0.15 to 0.60), p < 0.001 times the odds for patients with chlamydial infection, respectively. Of the women with gonorrhoea and previous pregnancy, 68% gave a history of abortion compared with 44% of those with chlamydial infection (p = 0.03). CONCLUSION: The identification of foci gonococcal and chlamydial infection and apparent location of these infections along the major transport routes in our health district require further study. That chlamydial infection, unlike gonorrhoea, is evenly distributed irrespective of population concentration and deprivation, suggests urgent need for a comprehensive local effort to control both STDs.

Adult↗
PubMed1995

Gene transfer by jet injection into differentiated tissues of living animals and in organ culture.

Jet injection can be used to introduce genes into the cells of differentiated tissues of living animals and organ cultures. When a solution of plasmid DNA is jet injected into a selected tissue or organ, cells lying in or near the path of the jet injection are transfected with the DNA and the introduced gene(s) are expressed. Since there is minimal morbidity from each jet injection, multiple injections can be performed at the same or nearby sites. Both mRNA and protein expression from transfected genes can be quantitated using standard methods. In addition, the technique is an efficient means of DNA immunization. Methodology for using jet injection to transfer plasmid DNA into the cells of skin, fat, mammary gland, and muscle are described.

Adipose Tissue↗
PubMed1995

Serum and colostrum antibody responses induced by jet-injection of sheep with DNA encoding a Cryptosporidium parvum antigen.

In an effort to generate high titer colostrum for immunotherapy of cryptosporidiosis, a study was conducted to test the efficacy of immunizing sheep with recombinant plasmid DNA (pCMV-CP15/60) encoding epitopes of 15 and 60 kDa surface antigens of Cryptosporidium parvum sporozoites. The plasmid DNA was used to immunize preparturient ewes at three dose levels by jet-injection into either hind limb muscle (IM) or mammary tissue (IMAM). Regardless of route of injection, a dose-dependent anti-CP15/60 immunoglobulin response was observed in sera and colostrum from sheep immunized with pCMV-CP15/60 plasmid DNA. High titer antibody responses were observed in one of three animals per group receiving an IM injection of 100 or 1000 micrograms pCMV-CP15/60. IMAM immunization with 100 or 1000 micrograms pCMV-CP15/60 plasmid DNA elicited higher titer colostrum responses and more consistent serum responses compared to IM injections. A negligible serum and colostrum anti-CP15/60 response was observed in ewes injected IM with 10 micrograms pCMV-CP15/60 or 1000 micrograms control plasmid DNA. Immunoblotting of native C. parvum sporozoite/oocyst protein with hyperimmune serum and colostrum corroborated the increased titers against CP15/60 antigen. Serum and colostrum antibodies from pCMV-CP15/60-immunized sheep were eluted from native CP15 protein and bound a surface antigen of C. parvum sporozoites as indicated by indirect immunofluorescence staining.

Animals↗
PubMed1995

The seasonal pattern of sheep blowfly strike in England and Wales.

Information on 4049 cases of sheep blowfly strike on 495 farms in England and Wales was gathered in a longitudinal survey conducted in 1991. The breech was the most commonly infested area, accounting for 70.9% of all strikes recorded. Body strikes accounted for 19.7% and foot strikes 11.4% of all strikes. Early in the season the incidences of both breech and body strikes were higher in ewes than in lambs, but from June to October lamb strikes predominated. The incidence of foot strike was greater in ewes than lambs throughout the year, with a peak incidence in September. Regional differences in strike incidence were evident; the highest overall incidences were recorded in the southern regions of England where peak incidence occurred earlier in the year. The highest monthly incidence risk was recorded in August in the south-east of England where there were 14.2 strikes per 1000 lambs and 4.0 strikes per 1000 ewes at risk. The importance of faecal soiling and ambient temperature are discussed.

Animals↗
PubMed1994

Ectoparasite control on sheep farms in England and Wales: the method, type and timing of insecticidal treatment.

The chemical control of sheep ectoparasites raises important environmental, health and welfare issues. There is increasing concern about the possible harmful effects of pesticides on human health and the role of dipping in the contamination of natural watercourses. A longitudinal survey was conducted in 1991, the last year of compulsory dipping for the control of sheep scab, to obtain information about the chemical control of ectoparasites on 485 farms in England and Wales. Organophosphate insecticides were the most commonly used for both summer and compulsory dipping and for spraying sheep, although many of the products used for spraying sheep were not licensed for this purpose. The early pattern of dipping and spraying appeared to follow the pattern of incidence of blowfly strike although more than 40 per cent of sheep were dipped during the first two weeks of the compulsory dipping period. Compulsory dipping for the control of sheep scab was reduced from two dips to one dip between 1988 and 1989 and removed altogether in 1992. The results from the survey were compared with the results of a previous survey and showed an apparent decline in the use of dipping and an increase in the use of alternative methods of control between 1988 and 1991.

Agriculture↗