Biomedical subjects

C Wright

Publications and source records attributed to C Wright.

At least 55 records · Page 3Linked to original sources

PubMed2001

Thermodynamic, kinetic and pH studies on the reactions of NCS-, N3-, and CH3CO2- with Fusarium galactose oxidase.

Thermodynamic and kinetic studies on the X- = NCS-, N3-, and CH3CO2- replacement of H2O/OH- at the CuII exogenous site of the tyrosyl-radical-containing enzyme galactose oxidase (GOaseox) from Fusarium (NRR 2903), have been studied by methods involving UV-vis spectrophotometry (25 degrees C), pH range 5.5-8.7, I = 0.100 M (NaCl). In the case of N3- and CH3CO2- previous X-ray structures have confirmed coordination at the exogenous H2O/OH- site. From the effect of pH on the UV-vis spectrum of GOaseox under buffer-free conditions, acid dissociation constants of 5.7 (pK1a; coordinated H2O) and 7.0 (pK2a; H+Tyr-495) have been determined. At pH 7.0 formation constants K(25 degrees C)/M-1 are NCS- (480), N3- (1.98 x 10(4)), and CH3CO2- (104), and from the variations in K with pH the same two pKa values are seen to apply. No pK1a is observed when X- is coordinated. From equilibration stopped-flow studies rate constants at pH 7.0 for the formation reaction kf(25 degrees C)/M-1 s-1 are NCS- (1.13 x 10(4)) and N3- (5.2 x 10(5)). Both K and kf decrease with increasing pH, consistent with the electrostatic effect of replacing H2O by OH-. In the case of the GOaseox Tyr495Phe variant pK1a is again 5.7, but no pK2a is observed, confirming the latter as acid dissociation of protonated Tyr-495. At pH 7.0, K for the reaction of four-coordinate GOaseox Tyr495Phe with NCS- (1.02 x 10(5) M-1) is more favorable than the value for GOaseox. Effects of H+Tyr-495 deprotonation on K are smaller than those for the H2O/OH- change. The pK1a for GOasesemi is very similar (5.6) to that for GOaseox (both at CuII), but pK2a is 8.0. At pH 7.0 values of K for GOasesemi are NCS- (270 M-1), N3- (4.9 x 10(3)), and CH3CO2- (107).

Carbonates↗

PubMed2001

Interconversion of Cu(I) and Cu(II) forms of galactose oxidase: comparison of reduction potentials.

A procedure for the preparation of the fully reduced Cu(I) form of galactose oxidase, GOase(red), involving reduction of GOase(semi) (or GOase(ox)) with non-coordinating [Ru(NH(3))(6)](2+) (51 mV vs. nhe) is described. Air-free conditions and a two-fold excess of [Ru(NH(3))(6)](2+) give a stable product with no further UV-Vis changes over >1.5 h. Rate constants for the reduction of GOase(semi) (k(f)=860 M(-1) s(-1)) give a first-order [H(+)]-dependence (pK(1a)=7.9), but the reverse process involving [Ru(NH(3))(6)](3+) oxidation of GOase(red) (k(b)=18.6 M(-1) s(-1)) is independent of pH (5.5 to 9.5). The reduction potential E(2)(o)' (vs. nhe) for the GOase(semi)/GOase(red) (i.e. Cu(II)/Cu(I)) couple is 149 mV at pH 7.5, which varies from 160 mV (pH 5.5) to 120 mV (pH 10.5), suggesting pK(1a) (GOase(semi)) and pK(2a) (GOase(red)) acid dissociation constants both involving Tyr-495. It is concluded that pK(2a) is for acid dissociation of uncoordinated H(+)Tyr-495. Consistent with this interpretation rate constants/M(-1) s(-1) for the GOase(semi) Tyr495 Phe variant, k(f)=1.59x10(3) and k(b)=16.1, respectively, are independent of pH and give a reduction potential of 169 mV. Comparisons are made of reduction potentials (E(1)(o)'/mV pH 7.5) for the GOase(ox)/GOase(semi) (i.e. Tyr(.)/Tyr) couple, and are for the Cys228Gly variant (630), for enzyme with N(3)(-) for H(2)O at the substrate binding exogenous site (393), and for apo-protein (570). These compare with previously reported values for the variants Trp290His (730) and Tyr495Phe (450), and together serve to quantify different contributions to the unusually small E(1)(o)' of 400 mV for the Tyr(.)/Tyr couple. At pH 7.5 the reduction potential for the two-equivalent GOase(ox)/GOase(red) couple is calculated to be 275 mV. The rate constant for the reaction of GOase(red) with GOase(ox) is 4.4x10(3) M(-1) s(-1) at pH 7.5.

Copper↗

PubMed2001

Prolonged longevity of hypopituitary dwarf mice.

In two types of mutant dwarf mice, congenital deficiencies in pituitary function are associated with remarkably increased life expectancy. In this review, we will describe the key phenotypic characteristics of these animals, the evidence that they exhibit delayed aging, and the mechanisms that are suspected to account for their prolonged longevity.

Aging↗

PubMed2001

Tomography of joint P-wave traveltime and polarization data: a simple approach for media with low to moderate velocity gradients.

An elastic wave tomography method utilizing joint traveltime and polarization data is proposed that is computationally simpler than the existing methods [Hu and Menke, Geophys. J. Int. 110, 63 (1992); Farra and Begat, Geophys. J. Int. 121, 371 (1995)]. In the linearization problem for the use of polarization data, we start with ray perturbation theory and assume that the medium is weakly inhomogeneous. Then the problem formulation for polarization data is approximately expressed as a linear integral of the gradient of the medium slowness perturbation along a reference ray. We call this a quasi-linear approximation which ignores the effect of the perturbation of the ray position on the first-order perturbation of the ray slowness vector. To efficiently obtain the solution for multi-data sets, a quadratic objective functional is constructed by including the data misfit terms and a model constraint term. Then a new conjugate gradient type of iterative reconstruction algorithm is developed to solve this minimization problem. This algorithm is also an extension of the conjugate gradient approach for standard least-squares problems. The feasibility and capability of the proposed tomography method is illustrated by conducting both noise-free and noisy synthetic experiments in a cross-hole geometry. The numerical results demonstrate that the additional use of polarization data not only improves the image quality, but also has a stabilizing effect on the iterative tomography solution. However, the limitation of the method is that it becomes inaccurate if the velocity variations in the medium change rapidly with position.

Journal Article↗

PubMed2001

Foot length, an accurate predictor of nasotracheal tube length in neonates.

BACKGROUND: Existing guidelines for optimal positioning of endotracheal tubes in neonates are based on scanty data and relate to measurements that are either non-linear or poorly reproducible in sick infants. Foot length can be measured simply and rapidly and is related to a number of external body measurements. OBJECTIVES: To evaluate the relation of foot length to nasotracheal length in direct measurements at post mortem examinations, and then compare its clinical relevance with traditional weight based estimates in a randomised controlled trial. METHODS: The dimensions of the upper airway were measured at autopsy in 39 infants with median (range) postmenstrual age and birth weight of 32 (24-43) weeks and 1630 (640-3530) g. The regression equations with 95% prediction intervals were calculated to estimate the optimal nasotracheal length from foot length. In a randomised trial, 59 neonates were nasally intubated according to foot length and body weight based estimates to assess the achievement of "optimal" and "satisfactory" tube placements. RESULTS: In the direct measurements of the airway at autopsy, foot length was a better predictor of nasotracheal distances (r(2) = 0.79) than body weight, gestational age, and head circumference (r(2) = 0.67, 0.58, and 0.60 respectively). Measurement of foot length was easy and highly reproducible. In the randomised controlled trial, there were no significant differences between the foot length and body weight based estimates in the rates of optimal (44% v 56%) and satisfactory (83% v 72%) endotracheal tube placements. CONCLUSIONS: Foot length is a reliable and reproducible predictor of nasotracheal tube length and is at least as accurate as the conventional weight based estimation. This method may be particularly valuable in sick unstable infants.

Analysis of Variance↗

PubMed2001

Approaching a consensus: psychosocial support services for solid organ transplantation programs.

BACKGROUND: Solid organ transplantation has become an accepted treatment for individuals with end-stage organ dysfunction. Criteria are being developed in the United States to determine medical eligibility for transplant candidates and competencies for transplant centers and physicians. To date, similar criteria for psychosocial services have not been developed. DESIGN AND SETTING: We queried participants in a specialty psychosocial transplant meeting to determine their views of which psychosocial services are essential to the comprehensive care of transplant patients in the United States. RESULTS: There was broad based multidisciplinary support for proactive pretransplant screening to discern individual psychosocial needs; focused pretransplant interventions to improve candidacy and future compliance; and posttransplant programs that address psychosocial, rehabilitation, and financial issues. CONCLUSION: Among psychosocial providers of solid organ transplantation services, there is support for expanding routine screening and support services to individuals who are candidates for and undergo solid organ transplantation.

Community Health Services↗

PubMed2001

Glucagon-like peptide 1 induces differentiation of islet duodenal homeobox-1-positive pancreatic ductal cells into insulin-secreting cells.

Glucagon-like peptide-1 (GLP-1) is an incretin hormone capable of restoring normal glucose tolerance in aging glucose-intolerant Wistar rats. Whether the antidiabetic properties of GLP-1 are exclusively due to its insulin secretory activity remains to be determined. A GLP-1-dependent differentiation of pancreatic precursor cells into mature beta-cells has recently been proposed. The aim of this study was to investigate whether pancreatic ductal epithelial cells could be differentiated into insulin-secreting cells by exposing them to GLP-1. Rat (ARIP) and human (PANC-1) cell lines, both derived from the pancreatic ductal epithelium, were used to test this hypothesis. A major difference distinguishes these two cell lines: whereas ARIP cells spontaneously express the beta-cell differentiation factor islet duodenal homeobox-1 (IDX-1), PANC-1 cells are characteristically IDX-1 negative. GLP-1 induced the differentiation of ARIP cells into insulin-synthesizing cells, although it did not affect the phenotype of PANC-1 cells, as determined by fluorescence-activated cell sorting (FACS) analysis. Differentiation of ARIP cells by exposure to human GLP-1 occurs in a time- and dose-dependent manner, and this is associated with an increase in IDX-1 and insulin mRNA levels. Secretion of insulin was also induced in a parallel manner, and it was regulated by the concentration of glucose in the culture medium. Interestingly, PANC-1 cells, when stably transfected with human IDX-1, gained responsiveness to GLP-1 and were able to differentiate into beta-cells, as determined by FACS analysis, insulin gene expression, intracellular insulin content, and insulin accumulation in the culture medium. Finally, we demonstrated that the receptor for GLP-1 is constitutively expressed by ARIP and PANC-1 cells and that the mRNA level for this transcript was increased by cellular transfection with human IDX-1. In summary, our study provides evidence that GLP-1 is a differentiation factor for pancreatic ductal cells and that its effect requires the expression of IDX-1.

Actins↗

PubMed2001

Home treatment for mental health problems: a systematic review.

OBJECTIVE: This review investigates the effectiveness of 'home treatment' for mental health problems in terms of hospitalisation and cost-effectiveness. For the purposes of this review, 'home treatment' is defined as a service that enables the patient to be treated outside hospital as far as possible and remain in their usual place of residence. METHODS - SYSTEMATIC LITERATURE SEARCH: 'Home treatment' excluded studies focused on day, residential and foster care. The review was based on Cochrane methodology, but non-randomised studies were included if they compared two services; these were only analysed if they provided evidence of the groups' baseline clinical comparability. METHODS - REVIEW OF ECONOMIC EVALUATIONS: Economic evaluations among the studies found were reviewed against established criteria. METHODS - IDENTIFICATION OF SERVICE COMPONENTS: A three-round Delphi exercise ascertained the degree of consensus among expert psychiatrists concerning the important components of community-based services that enable them to treat patients outside hospital. The identified components were used to construct the follow-up questionnaire. METHODS - FOLLOW-UP OF AUTHORS: As a supplement to the information available in the papers, authors of all the studies were followed up for data on service components, sustainability of programmes and service utilisation. METHODS - DATA ANALYSIS: The outcome measure was mean days in hospital per patient per month over the follow-up period. (1) Comparative analysis - compared experimental to control services. It analysed all studies with available data, divided into 'inpatient-control' and 'community-control' studies, and tested for associations between service components and difference in hospital days. (2) Experimental services analysis - analysed only experimental service data and tested for associations between service components and hospital days. RESULTS - SYSTEMATIC LITERATURE SEARCH: A total of 91 studies were found, conducted over a 30-year period. The majority (87) focused on people with psychotic disorders. RESULTS - REVIEW OF ECONOMIC EVALUATIONS: Only 22 studies included economic evaluations. They provided little conclusive evidence about cost-effectiveness because of problems with the heterogeneity of services, sample size, outcome measures and quality of analysis. RESULTS - DELPHI EXERCISE: In all, 16 items were rated as 'essential', falling into six categories: home environment; skill-mix; psychiatrist involvement; service management; caseload size; and health/social care integration. There was consensus that caseloads under 25 and flexible working hours over 7 days were important, but little support for caseloads under 15 or for 24-hour services, and consensus that home visiting was essential, but not on teams being 'explicitly dedicated' to home treatment. RESULTS - RESPONSE TO FOLLOW-UP: A total of 60% of authors responded, supplying data on service components and hospital days in most cases. Other service utilisation data were far less readily available. RESULTS - SERVICE CHARACTERISATION AND CLASSIFICATION: The services were homogeneous in terms of 'home treatment function' but fairly heterogeneous in terms of other components. There was some evidence for a group of services that were multidisciplinary, had psychiatrists as integrated team members, had smaller caseloads, visited patients at home regularly and took responsibility for both health and social care. This was not a cohesive group, however. RESULTS - SUSTAINABILITY OF SERVICES: The sustainability of home treatment services was modest: less than half the services whose authors responded were still identifiable. Services were more likely to be operational if the study had found them to reduce hospitalisation significantly. RESULTS - META-ANALYSIS: Meta-analysis with heterogeneous studies is problematic. The evidence base for the effectiveness of services identifiable as 'home treatment' was not strong. Within the 'inpatient-control' study group, the mean reduction in hospitalisation was 5 days per patient per month (for 1-year studies only). No statistical significance could be measured for this result. For 'community-control' studies, the reduction in hospitalisation was negligible. Moreover, the heterogeneity of control services, the wide range of outcome measures and the limited availability of data might have confounded the analysis. Regularly visiting at home and dual responsibility for health and social care were associated with reduced hospitalisation. Evidence for other components was inconclusive. Few conclusions could be drawn from the analysis of service utilisation data. RESULTS - LOCATION: Studies were predominately from the USA and UK, more of them being from the USA. North American studies found a reduction in hospitalisation of 1 day per patient per month more than European studies. North American and European services differed on some service components, but this was unlikely to account for this finding, particularly as no difference was found in their experimental service results. CONCLUSIONS - STATE OF RESEARCH: There is a clear need for further studies, particularly in the UK. The benefit of home treatment over admission in terms of days in hospital was clear, but over other community-based alternatives was inconclusive. CONCLUSIONS - NON-RANDOMISED STUDIES: Difficulties in systematically searching for non-randomised studies may have contributed to the smaller number of such studies found (35, compared with 56 randomised controlled trials). This imbalance was compounded by a relatively poor response rate from non-randomised controlled trial authors. Including them in the analysis had little effect. CONCLUSIONS - LIMITATIONS OF THIS REVIEW: A broad area was reviewed in order to avoid the problem of analysing by service label. While reviews of narrower areas may risk implying a homogeneity of the services that is unwarranted, the current strategy has the drawback that the studies cover a range of heterogeneous services. The poor definition of control services, however, is ubiquitous in this field, however reviewed areas are defined. Inclusion of mean data for which no standard deviations were available was problematic in that it prevented measuring the significance of the main findings. The lack of availability of this data, however, is an important finding, demonstrating the difficulty in seeking certainty in this area. Only days in hospital and cost-effectiveness were analysed here. The range and lack of uniformity of measures used in this field made meta-analysis of other outcomes impossible. It should be noted, however, that the findings pertain to these aspects alone. The Delphi exercise reported here was limited in being conducted only with psychiatrists, rather than a multidisciplinary panel. Its findings were used as a framework for the follow-up and analysis. Their possible bias should be borne in mind when considering them as findings in themselves. CONCLUSIONS - IMPLICATIONS FOR CLINICIANS: The evidence base for home treatment compared with other community-based services is not strong, although it does show that home treatment reduces days spent in hospital compared with inpatient treatment. There is evidence that visiting patients at home regularly and taking responsibility for both health and social care each reduce days in hospital. CONCLUSIONS - IMPLICATIONS FOR CONSUMERS: Services that visit patients at home regularly and those that take responsibility for both health and social care are likely to reduce time spent in hospital. Psychiatrists surveyed in this review also considered support for carers to be essential. The evidence from this review, however, was that few services currently have protocols for meeting carers' needs. CONCLUSIONS - RECOMMENDATIONS FOR RESEARCH AND COMMISSIONERS: A centrally coordinated research strategy, with attention to study design, is recommended. Studies should include economic evaluations that report health and social service utilisation. Service components should be collected and reported for both experimental and control services. Studies should be designed with adequate power and longer durations of follow-up and use comparable outcome measures to facilitate meta-analysis. Research protocols should be adhered to throughout the studies. It may be advisable that independent researchers conduct studies in future. It is no longer recommended that home treatment be tested against inpatient care, or that small, localised studies replicate existing, more highly powered studies.

Adolescent↗

PubMed2001

Drowning-related deaths in New Zealand, 1980-94.

OBJECTIVE: To describe the epidemiology of drowning in New Zealand for the period 1980-94. METHODS: Drowning-related incidents were identified by linking New Zealand Health Information Service and Water Safety New Zealand databases. RESULTS: 2,606 drowning-related incidents were identified. In three-quarters of the incidents, drowning was listed as the immediate cause of death. The majority of drownings were unintentional (85%), involved males (76%), and 0-4 and 15-24 year age groups had the highest rates. Boating was the leading cause of unintentional drowning (28%) followed by swimming and other water sports (19%), motor vehicle drownings (13%) and falls or slips (12%). CONCLUSIONS AND IMPLICATIONS: Although there has been a significant decline in drownings, New Zealand compares poorly internationally. In particular, our unintentional drowning rate is twice that of Australia. For New Zealand to continue to make substantial progress in addressing its overall drowning rate, we need to continue and strengthen our efforts in priority areas, in particular those due to motor vehicle crashes and boating and among pre-schoolers, adolescents and young adults. Motor vehicle traffic crashes warrant closer attention than has been the case to date.

Accidents↗

PubMed2000

Reflex effects of independent stimulation of coronary and left ventricular mechanoreceptors in anaesthetised dogs.

Previous studies which have indicated that the stimulation of ventricular mechanoreceptors induces significant reflex responses can be criticised because of the likelihood of concomitant stimulation of coronary arterial baroreceptors. We therefore undertook this investigation to examine the coronary and ventricular mechanoreflexes in a preparation in which the pressure stimuli to each region were effectively separated. Dogs were anaesthetised, artificially ventilated and placed on cardiopulmonary bypass. A balloon at the ventricular outflow separated pressure in the left ventricle from that perfusing the coronary arteries. Ventricular pressures were changed by varying inflow and outflow of blood entering and leaving the ventricle through an apical cannula, and coronary pressure by changing pressure in a reservoir connected to a cannula tied in the aortic root. Pressures distending carotid and aortic baroreceptors were controlled. Changes in descending aortic perfusion pressure (flow constant) were used to assess systemic vascular responses. Large changes in carotid sinus and coronary pressures decreased vascular resistance by 35+/-1.9 and 40+/-2.5%, respectively. Intracoronary injections of veratridine (30-60 microg) decreased vascular resistance by 31+/-2.5%. However, large increases in ventricular pressure decreased resistance by only 9+/-2.2%. Significant changes in vascular resistance were obtained with increases in coronary arterial pressure from 60 to 90 mmHg. However, ventricular pressures had to increase to 152/18 mmHg (systolic/end-diastolic) before there was a significant response. These results show that coronary mechanoreceptors are likely to play an important role in cardiovascular control. If ventricular receptors have any function at all, it is as a protective mechanism during gross distension, possibly associated with myocardial ischaemia.

Anesthesia↗

PubMed2000

Changing pattern of expression of parvalbumin immunoreactivity during human fetal spinal cord development.

Expression of the calcium binding protein parvalbumin (PV) by different classes of spinal neuron has been shown to be developmentally regulated in both rat and monkey. From postmortem studies of eight human cervical spinal cords ranging in age from 11 to 35 weeks postconceptional age, we report that parvalbumin immunoreactivity is similarly plastic in human lower cervical spinal cord development, with many changes occurring prenatally. At 11-14 weeks postconceptional age, there was prominent immunostaining of primary sensory afferents that could be seen coursing through the dorsal horn and extensively innervating the motoneuron pools. Motoneurons were also found to be clearly immunoreactive for choline acetyltransferase by this age. A few ventral horn neurons that were not motoneurons were also parvalbumin immunoreactive. By 24-27 weeks postconceptional age, sensory afferents were still immunoreactive, as were many other axons throughout the white matter. In addition, many ventral horn neurons were now immunoreactive as well as a few dorsal horn neurons. By 31-35 weeks postconceptional age, there was extensive immunostaining of neurons throughout the spinal cord, including a few moderately immunoreactive motoneurons. There were many immunopositive axons in all the white matter tracts except the corticospinal tracts; however, staining of sensory axons traversing the grey matter was less prominent by this age. In the rat, expression of PV by primary sensory neurons coincides with the onset of fetal limb movement. The onset of expression of PV in ventral horn neurons coincides with later developmental events after the arrival of corticospinal inputs, whereas widespread PV immunoreactivity in dorsal horn neurons marks the attainment of a mature pattern of PV expression. The extent to which expression of PV immunoreactivity can be taken to indicate landmarks in human development will be discussed.

Age Factors↗

PubMed2000

Are there gender differences in patients presenting with unstable angina?

BACKGROUND: There are limited studies on gender differences in patients with unstable angina. We investigated the influence of gender in these patients in a tertiary referral centre. METHODS AND RESULTS: Three hundred and thirteen consecutive patients (210 men and 103 women) with unstable angina were studied over a 42-month period. Patient characteristics, cardiovascular risk factors and subsequent management including coronary artery bypass graft (CABG) operation and percutaneous transluminal coronary angioplasty (PTCA) were investigated. There was no difference in age [61.6 (11.0) (S.D.) years for men vs. 63.5 (10.5) years for women]. Diabetes mellitus and hypertension were more common in women (diabetes, 11% vs. 23%, P = 0.007; hypertension, 32% vs. 52%; P = 0.001). The number of smokers was greater in men (73% vs. 46%, P = 0.00001). There was no difference in the prevalence of hypercholesterolaemia or in the incidence of previous myocardial infarction, previous history of angina and family history of ischaemic heart disease. The duration of unstable angina before presentation to the referring hospital was similar in both sexes. The use of aspirin, intravenous heparin and antianginal drugs was also comparable in the two genders. The number of coronary arteries involved in men and women appeared similar (one vessel, 22% vs. 27%; two vessels, 26% vs. 21%; three vessels, 52% vs. 52% in men and women, respectively). The proportion of men and women who underwent subsequent revascularisation was also similar (CABG, 31% vs. 33%; PTCA, 42% vs. 40%). The overall in-hospital mortality was higher in women (6.8% vs. 2.8%), but was not statistically significant (P = 0.18). CONCLUSIONS: Gender differences in unstable angina manifest in the preponderance of selected risk factors including diabetes mellitus and hypertension in women and smoking in men. There is no difference in age, the degree of coronary artery involvement and the subsequent management in a tertiary referral centre.

Angina, Unstable↗

PubMed2000

Pemphigus vulgaris of the uterine cervix revisited: case report and review of the literature.

Pemphigus vulgaris is an autoimmune disease characterized by acantholytic blisters and erosions involving the oral mucosa, skin, and less frequently other mucosal surfaces. Although the cytology of scrapings from the cutaneous and oral lesions has been well-documented, there are relatively few reports in the literature of the cytologic appearance of pemphigus on cervicovaginal smears. This report documents a case of pemphigus involving the cervix, in which the diagnosis was not known at the time of the cervical smear and biopsy. The cytologic features of this case and those in the literature are described in detail, highlighting the necessity of awareness of the disease and its presentation on cervicovaginal smears, in preventing an overdiagnosis of neoplasia.

Adult↗

PubMed2000

Human T lymphocyte genetic modification with naked DNA.

Endowing T lymphocytes with novel functional attributes by genetic modification is under development for a broad range of clinical cellular immunotherapy applications. To circumvent many of the limitations associated with viral vector systems, a plasmid-based electroporation system that reliably generates G418-resistant primary human T lymphocyte clones was developed. TCR alpha/beta+ CD4+CD8-, and CD4-CD8+ T lymphocyte clones can be routinely isolated from OKT3-stimulated peripheral blood mononuclear cells electroporated with linear plasmid DNA in a limiting dilution drug selection format. Fluorescence in situ hybridization (FISH) studies performed on T cell metaphase spreads using a probe specific for plasmid sequence demonstrated a single FISH signal doublet that varied in chromosomal location from clone to clone. Southern blot analysis using a Neo-specific probe verified chromosomal integration of plasmid vector at a single site. Band intensity quantitation of blots developed with a zeta-specific probe capable of annealing to both endogenous TCR-zeta and the introduced chimeric zeta sequence demonstrated that integrated plasmid was present at a single copy number. Expression levels of the CD20-specific chimeric immunoreceptor construct from a CMV immediate/early promoter present in the plasmid vector varied widely from clone to clone but remained stable during ex vivo expansion to cell numbers in excess of 10(10). This T lymphocyte genetic modification strategy is currently being piloted in a FDA-sanctioned adoptive therapy trial for recurrent lymphoma.

CD4-Positive T-Lymphocytes↗

PubMed2000

Vaccination of young lambs against infection with Nematodirus battus using gamma irradiated larvae.

Helminthologically naIve 6-week-old Suffolk lambs were given 1-3 doses of 20000 gamma-irradiated infective larvae (L3) of the nematode Nematodirus battus at weekly intervals. Following an anthelmintic drench they were challenged with 50000 viable L3 at 10 weeks of age. Nematode worm burdens 14 days post-challenge showed a significant (P<0.01) 66% reduction in the single vaccine dose group. The two and three dose groups had mean worm burdens which were 30 and 42% lower than controls, respectively, although these were not statistically significant. There was little measurable stimulation of the immune system in the vaccinated lambs, suggesting that the repeatedly dosed animals may have developed immunological unresponsiveness to the parasite.

Animals↗

PubMed2000

Transcription factor expression during pancreatic islet regeneration.

Recent studies by a number of laboratories have identified transcription factors that are involved in pancreatic development. Indeed, marked abnormalities in pancreatic development result from deficiencies in these molecules, which include, among others, PDX-1, islet-1 (Isl-1), and Pax-6. These studies have prompted us to evaluate the expression of Isl-1 and Pax-6 in the pancreas of the interferon-gamma (IFNgamma) transgenic mouse, which exhibits new islet growth and expansion of ducts throughout the life of the animal. We have previously demonstrated that PDX-1 is strikingly expressed in the ducts of the IFNgamma transgenic mouse. This latter observation compelled us to examine expression of hepatocyte nuclear factor-3beta (HNF3beta), which mediates PDX-1 gene transcription, in the IFNgamma transgenic pancreas as well. As a result of these studies, we now demonstrate marked expression of these transcription factors in the pancreatic ducts of IFNgamma transgenic mice. These data suggest a role for these transcription factors during pancreatic regeneration in the IFNgamma transgenic mouse.

Animals↗

PubMed2000

Failure to thrive in a population context: two contrasting studies of feeding and nutritional status.

Although failure to thrive (FTT) is generally thought to be a nutritional problem, dietary intake in children with FTT has been little researched. We describe two community-based studies of dietary intake and eating behaviour in FTT. The first study of ninety-seven children with FTT identified by population screening found that only a minority of case children were associated with neglect, organic illness or deprivation, even though dietary information suggested an underlying nutritional cause in the majority. Limited case-control data suggested significantly delayed weaning and less liking for food in general among the case children. The second study found diminished appetite, delayed progression onto solid foods and fewer foods eaten by forty-four children referred with FTT compared with forty-five controls, but was unable to detect a significant difference in energy intake, even allowing for varying body composition and other confounding variables. This study also revealed the bias introduced by recruiting case children by referral rather than screening, and that despite rigorous matching procedures the controls were not representative of the general population. These studies suggest a wide range of differences in eating behaviour and feeding patterns between children with FTT and controls, but suggest that measurements of nutrient totals may not be robust. Studies of FTT based on referred children can be misleading, as can comparison with controls, unless allowance can be made for important confounding social variables.

Diet↗

PubMed2000

Fetal diagnosis of lethal dysfunction of the right heart in three siblings.

A woman, having already delivered one child, underwent fetal echocardiography during three subsequent pregnancies. All three showed enlargement and poor function of the right-sided chambers. The first was still-born, the second died as a neonate, while the third pregnancy was terminated. Pathological examination revealed the same findings in each fetus, possibly representing a variation of Uhl's anomaly, or alternatively a hitherto unrecognised cardiomyopathic process.

Adult↗