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Biomedical subjects

J Dawson

Publications and source records attributed to J Dawson.

At least 37 records · Page 2Linked to original sources
PubMed2001

The Arabidopsis MALE STERILITY1 (MS1) gene is a transcriptional regulator of male gametogenesis, with homology to the PHD-finger family of transcription factors.

We report here the molecular characterisation of the Arabidopsis MALE STERILITY1 gene, which is a critical sporophytic controlling factor for anther and pollen development. Homozygous ms1 mutants do not produce viable pollen, but are otherwise phenotypically normal. Degeneration of pollen occurs soon after microspore release from the tetrads, at which time the tapetum also appears abnormally vacuolated. The MS1 gene is expressed at low levels in anthers from closed buds, with expression in the tapetum at the stage of microspore release. No expression is seen in open flowers. The deduced MS1 protein sequence shows strong homology to the PHD-finger motif found in known transcription factors from humans, yeast and higher plants. Six alleles of ms1 have been identified; all result in premature termination of the MS1 protein and loss of the PHD-finger motif. MS1 is likely to play a key role in regulating transcription during specific stages of male gametogenesis and anther development. As such, MS1 provides a valuable tool for the manipulation of male sterility in higher plants.

Amino Acid Motifs↗
PubMed2001

Uses of Community Treatment Orders in New Zealand: early findings.

OBJECTIVE: To assess the uses of Community Treatment Orders (CommTOs) in New Zealand. METHOD: A retrospective study of patients' records held by the regional administrator of mental health legislation and a survey of psychiatrists attending a conference in Dunedin. RESULTS: Males under Community Treatment Orders (CommTOs) outnumbered females 6:4; a high proportion were considered to have a major psychotic disorder; and one fifth remained under a CommTO for more than a year without inpatient care. Among the psychiatrists, there was a high level of agreement that, when used appropriately, the benefits of CommTOs outweigh their coercive impact on the patients; the most strongly supported indicator for use was the promotion of compliance with medication. The rate of use of CommTOs in Otago is remarkably similar to the rate in Victoria, Australia. CONCLUSIONS: Records suggest that a significant proportion of patients under CommTOs are not soon readmitted; and many clinicians in New Zealand consider CommTOs to be a useful strategy for managing the community care of long-term patients with schizophrenia and major affective disorders.

Adult↗
PubMed2001

Snapshots of five clinical ethics committees in the UK.

Each of the following papers gives an account of a different UK clinical ethics committee. The committees vary in the length of time they have been established, and also in the main focus of their work. The accounts discuss the development of the committees and some of the ethical problems that have been brought to them. The issues raised will be relevant for other National Health Service (NHS) trusts in the UK that wish to set up such a committee.

Committee Membership↗
PubMed2001

Legal pitfalls of psychiatric research.

BACKGROUND: The increasing complexity of psychiatric research, including recent attempts to evaluate mental health legislation, suggests legal advice may be valuable in a wide range of research contexts. AIMS: We aim to illustrate both the legal pitfalls of research in psychiatry and the potential for solutions if the methods are carefully chosen. METHOD: Two examples of research are subject to legal analysis, one involving advance directives, the other the random discharge of compulsory out-patients. RESULTS: This analysis illustrates that participation in research may expose clinicians to additional forms of liability, but the legal risks can be minimised through changes in the methods or additional safeguards. CONCLUSIONS: Collaboration between academic law and psychiatry can enrich research agendas and avoid serious legal pitfalls. We argue that sound legal advice should be sought at the planning stage of research in psychiatry, but the fear of liability should not lead to overly defensive research practices. The aim should be to strike the right balance between avoiding unacceptable exposure to liability and stifling innovative research.

Advance Directives↗
PubMed2001

The benefits of using patient-based methods of assessment. Medium-term results of an observational study of shoulder surgery.

We carried out a prospective study of 93 patients undergoing surgery for conditions of the rotator cuff during 1994 and 1995. They were assessed before operation and after six months, and four years, using the patient-based Oxford Shoulder Score (OSS), the SF-36 questionnaire and the Constant shoulder score. The response rates were higher for the OSS and SF-36. The correlation coefficients were high (r > 0.5) between all scores at each stage of the study. While all scores improved substantially at six months, the Constant score was reduced significantly at four years. This did not correlate with the patients' judgement of the change in symptoms or of the success of the operation. Our study suggests that patient-based measures of pain and function can reliably assess outcomes in the medium term after surgery to the shoulder.

Humans↗
PubMed2001

Evidence for the validity of a patient-based instrument for assessment of outcome after revision hip replacement.

The Oxford hip score (OHS) is a patient-based instrument for assessment of outcome which is often used after total hip replacement, and the EuroQol 5D (EQ5D) is a patient-based generic questionnaire for health assessment. In an analysis of the outcome at one year of 609 revision hip replacements (RHRs), we compared the OHS and EQ5D scores, postoperative patient satisfaction and change in pain. About 25% of the operations were repeat RHRs. At one year, 57% of patients were very pleased with their operation. The correlation between preoperative and postoperative scores and change scores for the OHS and EQ5D was high. For both instruments the effect sizes were large, but the greater effect size of the OHS suggests that it is particularly sensitive to improvements after RHR. The effect scores of the OHS declined with the number of previous RHRs, while those for the EQ5D seemed less sensitive. Our results confirm the value of the OHS in assessing outcome after RHR.

Arthroplasty, Replacement, Hip↗
PubMed2001

Survival of poliovirus in New Zealand green-lipped mussels, Perna canaliculus, on refrigerated and frozen storage.

Poliovirus survival in live and frozen mussels during storage was assessed by both viral culture and molecular methods. Live New Zealand green-lipped mussels were incubated overnight at 20 degrees C in an aerated tank of filtered seawater seeded with the poliovirus 2 (PV2) vaccine strain. An extraction and concentration method that preserved viral infectivity was used to recover PV2 taken up by the mussels at day 0, at day 2 after storage at 4 degrees C, and at days 7, 14, and 28 after storage at -20 degrees C. This method allowed both culture and molecular analysis to be carried out. Presence of intact PV2 in each batch of mussels was determined by a pan-enterovirus specific reverse transcription-polymerase chain reaction (RT-PCR) and confirmed by dot-blot hybridization. Survival of infectious PV2 was determined by the monolayer plaque assay. After 48 h at 4 degrees C, infectious PV2 levels were 81% of the original level detected in the mussels. Infective virus levels then declined to 66, 53, and 44% after storage at -20 degrees C for 7, 14, and 28 days, respectively. Generic RT-PCR methods were 10 times more sensitive than cell culture techniques for virus detection but did not give information on virus infectivity. The survival of infectious pathogenic viruses in fresh and frozen mussels on storage constitutes a potential health risk and so is a major concern for public health authorities.

Animals↗
PubMed2001

Law, ethics and epidemiology: the case of the cervical screening audit.

This paper provides a legal and ethical analysis of some controversial aspects of a recent proposal for an independent audit of New Zealand's National Cervical Screening Programme. The analysis reveals the difficulties likely to arise between investigators and ethics committees when the interests served by important public health research compete with the rigorous protection of patients' privacy.

Access to Information↗
PubMed2000

Intrauterine cytomegalovirus infection and glycoprotein B genotypes.

Cytomegalovirus (CMV) strains display polymorphisms for the gene encoding glycoprotein B (gB; gpUL55). Recent data suggest that the gB genotype may influence the outcome of acquired CMV infections. To determine whether the gB genotype also contributes to the outcome of intrauterine infection, CMV strains were studied from 56 infants with culture-confirmed intrauterine CMV infections who were born in Iowa or Texas. CMV gB genotypes were compared with the neonatal clinical features and neurodevelopmental outcomes. Fifty-three strains (95%) could be assigned a gB genotype. The overall distribution of genotypes was as follows: type 1, 50%; type 2, 18%; type 3, 23%; and type 4, 4%. Strains with the gB 3 genotype were more common among the Iowa infants (P=.082). The gB 3 genotype was more common among infants with asymptomatic infections (P=.004), but geographic location and ascertainment biases may have accounted for these differences. The gB genotypes did not correlate with the neurodevelopmental outcome of intrauterine infection.

Cytomegalovirus↗
PubMed2000

Visual attention impairments in Alzheimer's disease.

BACKGROUND: Impaired attention can hinder information processing at multiple levels and may explain aspects of functional decline in aging and dementia. Impairments of attention in early AD may contribute to performance reductions in other cognitive domains, including memory and executive functions. METHOD: - The authors analyzed the scores on a battery of tests of attention and cognitive abilities in 64 older individuals: 42 with mild AD and 22 control subjects without dementia. The authors tested the hypotheses that patients with AD would have impairments of visual attention, and that these impairments would correlate with dysfunction in other key cognitive domains. RESULTS: Patients with AD performed significantly worse than control subjects on measures of sustained attention, divided attention, selective attention, and visual processing speed. The differences were not due to differences in age, education, or basic visual function. Strong relationships were identified between reduced attention skills and overall cognitive impairment. CONCLUSIONS: Deterioration of attention abilities occurs in early stages of AD, and likely contributes to functional decline in these patients. More routine assessment of visual attention deficits could give a more accurate measure of functionally useful perception in patients with AD who show normal visual acuity and visual fields, perhaps providing useful clues to diagnosis and staging.

Aged↗
PubMed2000

Vision and cognition in Alzheimer's disease.

Alzheimer's disease (AD) is known to affect visual pathways, but potential concomitant effects on vision and cognitive performance are not well understood. We studied 43 individuals with AD of mild severity and 22 individuals without dementia on a battery of tests designed to measure multiple aspects of basic and higher-order visual perception and cognition. All subjects performed on the same visual and cognitive test batteries. The results showed no differences between groups on tests of static visual acuity, stereoacuity, dynamic visual acuity or motion direction discrimination. However, individuals with AD performed significantly worse on tests of static spatial contrast sensitivity, visual attention, shape-from-motion, color, visuospatial construction and visual memory. Correlation analyses showed strong relationships between visual and cognitive scores. The findings show that AD affects several aspects of vision and are compatible with the hypothesis that visual dysfunction in AD may contribute to performance decrements in other cognitive domains. The pattern of involvement indicates that AD affects multiple visual neural pathways and regions. It is possible that better understanding of vision-related dysfunction could aid diagnosis and interventions to improve functional capacity in patients with dementia.

Aged↗
PubMed2000

Influence of environmental factors on virus detection by RT-PCR and cell culture.

The effects of clay, humic acid, u.v. light and shellfish tissue residues on the detection of poliovirus type 2 from environmental samples by culture and RT-PCR were investigated. RT-PCR showed 10-100 times greater sensitivity for PV2 detection in the absence of sample contaminants than did culture by plaque assay in BGM cell monolayers. Bentonite clay (100-1000 mg l-1) and shellfish tissue residues reduced virus detection by plaque assay, but the effect of bentonite was mitigated by simple elution procedures. Bentonite clay, humic acid (5-150 mg l-1) and mussel tissue reduced virus detection by RT-PCR by between 1 and 8 logs, although this was mitigated in part by elution and Sephadex filtration of extracts. Sephadex filtration of samples reduced culturable PV2 by 32-50%. Exposure of PV2 in water to u.v. light reduced culturability of PV2 but not detection by RT-PCR. This study demonstrates that virus detection in environmental samples is strongly influenced by naturally occurring substances and disinfection approaches. The accuracy of results of viral analyses of this nature should be carefully scrutinized with respect to sample constituents.

Animals↗
PubMed2000

Issues relating to long-term follow-up in hip arthroplasty surgery: a review of 598 cases at 7 years comparing 2 prostheses using revision rates, survival analysis, and patient-based measures.

We reviewed 598 cemented Charnley and Hi-nek total hip arthroplasties at 7 years. Data were obtained from general practitioners, hospital medical notes, microfilm, and patient questionnaires. Outcome measures were revision rates, survival analysis, 12-item Oxford Hip Score, and satisfaction ratings. There were 471 Charnley (79%) and 127 Hi-nek (21%) total hip arthroplasties; 139 deaths (23%) occurred, and 5 (<1%) were lost to follow-up. Characteristics of the Charnley and Hi-nek patient groups were similar, with more information missing for Charnley cases. Revision rates were Charnley, 37 (8%), and Hi-nek, 6 (5%) (not significant). Survival analysis revealed no difference between the 2 groups (P = .23). The patients' median Oxford Hip Score was low/good (19), slightly worse for the Hi-nek group (not significant). Taking all evidence together, neither implant was outperforming the other at 7 years.

Arthroplasty, Replacement, Hip↗
PubMed2000

Maternal nutrient restriction during early to mid gestation alters the relationship between insulin-like growth factor I and bodyweight at term in fetal sheep.

The present study was designed to determine whether altered placental size, as a consequence of maternal nutrient restriction in sheep between 28 and 77 days gestation, is associated with a modified relationship between fetal weight or dimensions and plasma insulin-like growth factor (IGF) I concentration or abundance of hepatic IGF-I and IGF-II mRNA close to term. Singleton-bearing ewes consumed either 1.2x (controls, n = 19) or 0.5x (nutrient restricted, n = 28) their metabolizable energy (ME) requirements from 28 to 77 days gestation, after which all ewes were fed in order to fully meet their ME requirements for maintenance and pregnancy. Close to term (145 +/- 1 days) plasma IGF-I concentration in cord blood was similar between groups, but only significantly correlated with fetal bodyweight, thoracic circumference, crown-rump length and lean body mass in lambs born to control (r2 0.38, 0.76, 0.33, 0.42; P<0.001), and not to nutrient-restricted (r2 = 0.01, 0.11, 0.01, 0.02) ewes. There were no differences in fetal hepatic expression of IGF-I and IGF-II mRNA between groups close to term. In conclusion, maternal nutrient restriction in early to mid gestation followed by feeding to requirements up to term alters the relationship between fetal IGF-I, bodyweight and length. Increasing maternal nutrition in later gestation after a prolonged period of nutrient restriction may stimulate fetal nutrient supply such that fetal growth is enhanced without an increase in plasma IGF-I. As a result, there is a loss of the relationship between fetal weight and plasma IGF-I concentration observed in fetuses whose mothers are fed adequately throughout gestation.

Animals↗
PubMed2000

Risk factors for candidemia in Neonatal Intensive Care Unit patients. The National Epidemiology of Mycosis Survey study group.

BACKGROUND: Candida species are important nosocomial pathogens in neonatal intensive care unit (NICU) patients. METHODS: A prospective cohort study was performed in six geographically diverse NICUs from 1993 to 1995 to determine the incidence of and risk factors for candidemia, including the role of gastrointestinal (GI) tract colonization. Study procedures included rectal swabs to detect fungal colonization and active surveillance to identify risk factors for candidemia. Candida strains obtained from the GI tract and blood were analyzed by pulsed field gel electrophoresis to determine whether colonizing strains caused candidemia. RESULTS: In all, 2,847 infants were enrolled and 35 (1.2%) developed candidemia (12.3 cases per 1,000 patient discharges or 0.63 case per 1,000 catheter days) including 23 of 421 (5.5%) babies < or =1,000 g. After adjusting for birth weight and abdominal surgery, forward multivariate logistic regression analysis demonstrated significant risk factors, including gestational age <32 weeks, 5-min Apgar <5; shock, disseminated intravascular coagulopathy, prior use of intralipid, parenteral nutrition, central venous catheters, H2 blockers, intubation or length of stay > 7 days before candidemia (P < 0.05). Catheters, steroids and GI tract colonization were not independent risk factors, but GI tract colonization preceded candidemia in 15 of 35 (43%) case patients. CONCLUSIONS: Candida spp. are an important cause of late onset sepsis in NICU patients. The incidence of candidemia might be decreased by the judicious use of treatments identified as risk factors and avoiding H2 blockers.

Candida↗