PubMed Health⌕ Search

Biomedical subjects

J Dodgson

Publications and source records attributed to J Dodgson.

At least 19 recordsLinked to original sources
PubMed2005

Direct evidence of host genome acquisition by the alphaherpesvirus Marek's disease virus.

Many herpesviruses including Marek's disease virus (MDV), a poultry alphaherpesvirus, carry homologous host genes presumably acquired during viral evolution. We have characterized one recent acquisition by MDV in considerable detail. The virulent MDV strain Md11 previously was isolated from a commercial chicken and initially propagated on duck cells. In the process of cloning the entire Md11 genome in a bacterial artificial chromosome (BAC), we obtained an infectious clone in which the entire terminal repeat short segment was replaced with a portion of the duck genome that corresponds to chicken chromosome 19. This sequence is not predicted to express any protein even though it contains one exon of the VAMP1 gene. The replacement did not affect MDV replication in vitro, despite the virus having only one copy of ICP4. Furthermore, we have shown that the variant MDV genome containing the duck genome substitution is present in the parental Md11 population and has been maintained through several subsequent propagations of the virus on chicken cells. This finding provides direct evidence that host genome acquisition by MDV actually occurs during virus replication, and that one or more such MDV genomes with host sequences may exist within MDV viral stocks which tend to be polyclonal, due to the cell-associated nature of its infection process.

Animals↗
PubMed2000

A consensus linkage map of the chicken genome.

A consensus linkage map has been developed in the chicken that combines all of the genotyping data from the three available chicken mapping populations. Genotyping data were contributed by the laboratories that have been using the East Lansing and Compton reference populations and from the Animal Breeding and Genetics Group of the Wageningen University using the Wageningen/Euribrid population. The resulting linkage map of the chicken genome contains 1889 loci. A framework map is presented that contains 480 loci ordered on 50 linkage groups. Framework loci are defined as loci whose order relative to one another is supported by odds greater then 3. The possible positions of the remaining 1409 loci are indicated relative to these framework loci. The total map spans 3800 cM, which is considerably larger than previous estimates for the chicken genome. Furthermore, although the physical size of the chicken genome is threefold smaller then that of mammals, its genetic map is comparable in size to that of most mammals. The map contains 350 markers within expressed sequences, 235 of which represent identified genes or sequences that have significant sequence identity to known genes. This improves the contribution of the chicken linkage map to comparative gene mapping considerably and clearly shows the conservation of large syntenic regions between the human and chicken genomes. The compact physical size of the chicken genome, combined with the large size of its genetic map and the observed degree of conserved synteny, makes the chicken a valuable model organism in the genomics as well as the postgenomics era. The linkage maps, the two-point lod scores, and additional information about the loci are available at web sites in Wageningen (http://www.zod.wau.nl/vf/ research/chicken/frame_chicken.html) and East Lansing (http://poultry.mph.msu.edu/).

Animals↗
PubMed1998

Factors associated with very early weaning among primiparas intending to breastfeed.

OBJECTIVES: The major objective of this study was to identify predictor variables that accurately differentiated breastfeeding women who weaned during the first 4 weeks, those who weaned between 5 and 26 weeks, and those who weaned after 26 weeks. Predictors were demographic variables, Theory of Planned Behavior (TPB) variables, breastfeeding knowledge, and difficulties experienced during the first month. METHODS: Primiparas who delivered healthy infants in an urban midwestern hospital provided initial data prior to discharge. Follow-up occurred at 1, 3, 6, 9, and 12 months. Following appropriate bivariate analyses, polychotomous logistic regression was used to determine predictors of weaning group. Linear multiple regression was used to predict intended duration. RESULTS: Most of the 84 women who weaned very early had intended to breastfeed considerably longer. According to the multivariate analysis, women who weaned earlier were younger, had completed fewer years of education, had a more positive bottle-feeding attitude and a less positive breastfeeding attitude, intended to breastfeed less time, had lower knowledge scores, had higher perceived insufficient milk scores, and planned to work outside the home. Variables postulated by the TPB to be direct predictors of intention explained 36% of the variance in intended duration. CONCLUSIONS: Women at risk for early weaning can be identified with reasonable accuracy using a TPB-based conceptual framework expanded to include breastfeeding specific variables. Casefinding using empirically derived screening methods and careful postpartum follow-up, along with professional intervention, should be used to avert unintended early weaning.

Adolescent↗
PubMed1992

A review of caesarean sections at 30 weeks gestation or less in the west of Scotland 1988-1989.

A retrospective study was carried out of caesarean sections at 30 completed weeks of gestation or less between 1/1/88 and 31/12/89 in Glasgow and The West of Scotland. One hundred and thirty-three caesarean sections were carried out resulting in 150 babies. Fifteen (11.3%) of these were classical sections. There were 30 neonatal deaths. The perinatal mortality rate was 170 per 1000. Survival was related to increasing gestation from 27 weeks onwards and also to birthweight from 900 grams onwards. In-utero transfers fared badly with seven out of 21 babies (33%) failing to survive beyond the neonatal period. Although survival continues to improve in newborns, the use of caesarean section should still be viewed with caution as the benefits in the very premature situation with regard to infant survival may be outweighed by the increased maternal morbidity both in the present pregnancy and future pregnancies.

Birth Weight↗
PubMed1991

v-erbA overexpression is required to extinguish c-erbA function in erythroid cell differentiation and regulation of the erbA target gene CAII.

The v-erbA oncoprotein represents a retrovirus-transduced oncogenic version of the thyroid hormone (T3/T4) receptor c-erbA (type alpha). It contributes to virus-induced erythroleukemia by efficiently arresting differentiation of red cell progenitors and by suppressing transcription of erythrocyte-specific genes. Here, we show that v-erbA and c-erbA bind directly to sequences within the promoter of the erythrocyte-specific carbonic anhydrase II (CAII), a gene whose transcription is efficiently suppressed by v-erbA. This erbA-binding site confers thyroid hormone responsiveness to a heterologous promoter in transient expression experiments and is a target for efficient down-regulation of CAII transcription by the v-erbA oncoprotein. In stably transformed erythroblasts coexpressing the v-erbA oncoprotein and the c-erbA/T3 receptor at an approximately equimolar ratio, c-erbA activity is dominant over v-erbA. T3 efficiently induced erythroid differentiation in these cells, thus overcoming the v-erbA-mediated differentiation arrest. Likewise, T3 activated CAII transcription as well as transient expression of a T3-responsive reporter gene containing the CAII-specific erbA-binding site. The c-erbA-dependent activation of this CAII reporter construct could only be suppressed by very high amounts of v-erbA. Our results suggest that overexpression of v-erbA is required for its function as an oncoprotein.

Base Sequence↗
PubMed1989

The increasing problem in Tayside of cervical cancer in younger women.

The incidence of cervical carcinoma in younger women is increasing in Tayside despite a decrease in the overall incidence. However, stage for stage, we did not encounter a poorer survival in younger patients. A number of patients had been sterilised or had a pregnancy when cytological screening was available and not made use of. There were also some false negative smears which were reclassified for retrospective analysis. We would recommend cervical screening every three years and careful inspection of the cervix and a smear taken in cases of abnormal gynaecological symptoms such as post coital bleeding.

Adenocarcinoma↗
PubMed1989

Comparative studies of airborne asbestos in occupational and non-occupational environments using optical and electron microscope techniques.

We have compared asbestos fibre and general fibre counts from scanning electron microscopy (SEM) and transmission electron microscopy (TEM) with fibre counts from phase-contrast optical microscope (PCOM) methods. Three different types of sample have been evaluated: laboratory-prepared samples of different fibre types; chrysotile asbestos textile factory samples; and non-occupational and environmental samples from sites where asbestos might be found. TEM produced total fibre number assessments which were greater than those found with SEM which, in turn, produced fibre counts greater than those obtained with the PCOM. However, when fibres longer than 5 microns were alone counted, the two electron microscope (EM) methods provided similar results. This indicates that TEM is advantageous in comparison with SEM when counting or sizing short fibres and has no advantage for fibres longer than 5 microns. For fibres longer than 5 microns in both the laboratory-prepared and asbestos factory samples, the EM asbestos counts were higher than the PCOM fibre counts, the ratios depending on the fibre type in the case of the former. The PCOM fibre counts in samples from the non-occupational situations were shown to be poor predictors of airborne asbestos fibre concentrations determined by EM. This was mainly due to the presence of high and variable proportions of non-asbestos fibres in these samples. It is concluded that, in order to convert EM asbestos fibre concentrations (greater than 5 microns) to equivalent PCOM asbestos concentrations, they should be divided by 4.0 for chrysotile and 1.7 for amphibole asbestos.

Air Pollutants↗
PubMed1988

Risk factors in the development of cervical intraepithelial neoplasia in women with vulval warts.

Of 59 women referred with vulval warts whose cervices were assessed colposcopically for the presence of cervical intraepithelial neoplasia (CIN) before local treatment of the wart lesions, 17 had histologically proved CIN, 12 had histologically proved cervical wart virus infection, and 30 had abnormality on colposcopy or cytology. Seven of the 17 with CIN had no abnormality on cervical cytology. No differences in sexual behaviour, smoking habit, or oral contraceptive use were seen between women with CIN and those with no cervical abnormality. Viral DNA typing of the vulval lesions was carried out, but there were no differences in the distribution of viral types between the three different histological groups. Of the 30 women with no abnormality at the initial visit, 23 were followed up colposcopically and cytologically for one to two years. Three of them developed CIN after adequate treatment of the vulval lesions despite the absence of cervical abnormalities on colposcopy at the time of treatment. Studying the known factors linked with CIN failed to show why some women with vulval warts develop CIN, even after treatment of the warts, and others do not. The large number of false negative results on cervical cytology in our patients suggests that women presenting with vulval warts should be screened colposcopically in the first instance. Close follow up of women whose warts are treated and who are thought to have no cervical abnormality at that assessment is essential.

Adult↗
PubMed1987

Severe pregnancy-induced hypertension: postpartum care of the critically ill patient.

SPIH is a disease of unknown cause that contributes to maternal and neonatal morbidity and mortality rates. Familiarity with the normal physiologic adaptations of pregnancy and the confounding pathologic changes of SPIH will enable the health care professional to better understand the principles of management. Immediate therapeutic interventions are necessary to reverse hypertension and to prevent the life-threatening sequelae that may arise from this condition. Postpartum management is directed toward decreasing vasospasm and central nervous system irritability and maintaining fluid and electrolyte balance. Attention must be given to the special obstetric needs of these patients.

Acute Disease↗
PubMed1986

Does mild atypia on a cervical smear warrant further investigation?

228 women referred to a colposcopy clinic over a 10-year period with mildly atypical cervical cytology had a histological diagnosis established by colposcopically directed biopsy. Of the 187 women (82.0%) who had dyskaryosis on the referral smear, 129 (69%) had cervical intraepithelial neoplasia (CIN) grade II or III on histology, as did 12 (29.2%) of the 41 women without dyskaryosis. 27.6% of smears taken at the time of colposcopy had normal cytology, although a third of these women had CIN II or III diagnosed on histology at that time. The poor correlation between mildly atypical cervical cytology and histology suggests that the practice of relying on cytology alone for the surveillance of women who have already had an atypical smear should be discouraged.

Adult↗
PubMed1986

Updating lung cancer mortality among a cohort of man-made mineral fibre production workers in seven European countries.

A historical cohort of 21,967 workers ever employed in 13 European factories manufacturing various types of man-made mineral fibres (MMMF) was observed until 1982. Overall there were 2719 deaths (standardised mortality ratio (SMR) = 111) of which 189 were from lung cancer (SMR = 125). For the glasswool and rockwool/slagwool production subcohorts the lung cancer SMRs rose with time since first exposure, exceeding 170 for the period of 30 or more years. Adjustment for regional variations in mortality substantially reduced the excess in the glasswool group, but not in the rockwool/slagwool. In neither subgroup was there any relationship of lung cancer mortality with length of employment. During the early years of rockwool/slagwool production there was the potential for much higher fibrous dust exposure than at present, because of the absence of dust suppressing oil and/or the use of a batch production process. In addition slag was widely used as a raw material. Amongst workers employed during the early phase, there were 10 lung cancer deaths giving SMRs of 270 and 244 for the periods 20-29 and 30 or more years since first exposure. This group accounts for most of the absolute excess of lung cancer for the rockwool/slagwool plants.

Adult↗
PubMed1986

Environmental surveys in the European man-made mineral fiber production industry.

This paper presents estimates of airborne fiber concentrations and fiber size for European man-made mineral fiber (MMMF) factories on the basis of measurements made in 1977-1980. The airborne fiber concentrations previously reported at a conference of the World Health Organization (WHO) and the International Agency for Research on Cancer in 1982 have been revised to harmonize the results with the WHO-European MMMF reference counting level. The result was an approximate doubling of the reported airborne fiber levels. After the revisions the average combined occupational group concentrations in the rock- and glass-wool plants were still generally low (less than 0.01 fibers/ml). In the glass continuous-filament factories the airborne fiber concentrations were very low (less than 0.01 fibers/ml). The average plant median for fiber length ranged from 10 to 20 microns, and the corresponding median diameters ranged from 0.7 to 2 microns. In general the glass-wool fibers were thinner than the rock-wool fibers. The fiber concentrations measured in other studies in the MMMF production and user industries are reviewed. Higher levels (between 0.1 and 1.0 fibers/ml) have been measured in some insulation wool production, secondary production, and user industries. The highest levels (greater than 1.0 fibers/ml) occurred in very fine glass-fiber production and in other specialist insulation wool usage.

Air Pollutants, Occupational↗