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Biomedical subjects

R E Green

Publications and source records attributed to R E Green.

At least 19 recordsLinked to original sources

Diclofenac disposition in Indian cow and goat with reference to Gyps vulture population declines.

Gyps vultures across India are declining rapidly and the NSAID diclofenac has been shown to be the major cause. Vultures scavenge livestock carcasses that have been treated with diclofenac within the days preceding death. We present data on diclofenac disposition in Indian cow and goat, and field data on the prevalence of diclofenac in carcases in the environment. In the disposition experiment, animals were treated with a single intramuscular injection of diclofenac at 1000 microg kg-1 bw. In cow, diclofenac was detectable in liver, kidney and intestine up to 71 h post-treatment; in plasma, half-life was 12.2 h. In goat, tissue residues were undetectable after 26 h. Prevalence of diclofenac in liver from 36 dead livestock collected in the field was 13.9%. Data suggest that diclofenac residues in Indian cow and goat are short-lived, but diclofenac prevalence in carcasses available to vultures may still be very high.

Animals↗

Patterns of nucleotide misincorporations during enzymatic amplification and direct large-scale sequencing of ancient DNA.

Whereas evolutionary inferences derived from present-day DNA sequences are by necessity indirect, ancient DNA sequences provide a direct view of past genetic variants. However, base lesions that accumulate in DNA over time may cause nucleotide misincorporations when ancient DNA sequences are replicated. By repeated amplifications of mitochondrial DNA sequences from a large number of ancient wolf remains, we show that C/G-to-T/A transitions are the predominant type of such misincorporations. Using a massively parallel sequencing method that allows large numbers of single DNA strands to be sequenced, we show that modifications of C, as well as to a lesser extent of G, residues cause such misincorporations. Experiments where oligonucleotides containing modified bases are used as templates in amplification reactions suggest that both of these types of misincorporations can be caused by deamination of the template bases. New DNA sequencing methods in conjunction with knowledge of misincorporation processes have now, in principle, opened the way for the determination of complete genomes from organisms that became extinct during and after the last glaciation.

Animals↗

The transcriptional landscape of the mammalian genome.

This study describes comprehensive polling of transcription start and termination sites and analysis of previously unidentified full-length complementary DNAs derived from the mouse genome. We identify the 5' and 3' boundaries of 181,047 transcripts with extensive variation in transcripts arising from alternative promoter usage, splicing, and polyadenylation. There are 16,247 new mouse protein-coding transcripts, including 5154 encoding previously unidentified proteins. Genomic mapping of the transcriptome reveals transcriptional forests, with overlapping transcription on both strands, separated by deserts in which few transcripts are observed. The data provide a comprehensive platform for the comparative analysis of mammalian transcriptional regulation in differentiation and development.

3' Untranslated Regions↗

Monitoring change in biodiversity through composite indices.

The need to monitor trends in biodiversity raises many technical issues. What are the features of a good biodiversity index? How should trends in abundance of individual species be estimated? How should composite indices, possibly spanning very diverse taxa, be formed? At what spatial scale should composite indices be applied? How might change-points--points at which the underlying trend changes--be identified? We address some of the technical issues underlying composite indices, including survey design, weighting of the constituent indices, identification of change-points and estimation of spatially varying time trends. We suggest some criteria that biodiversity measures for use in monitoring surveys should satisfy, and we discuss the problems of implementing rigorous methods. We illustrate the properties of different composite indices using UK farmland bird data. We conclude that no single index can capture all aspects of biodiversity change, but that a modified Shannon index and the geometric mean of relative abundance have useful properties.

Animals↗

Neuropsychologic impairment after coronary bypass surgery: effect of gaseous microemboli during perfusionist interventions.

OBJECTIVE: Neuropsychologic impairment is a common complication of coronary bypass surgery. Cerebral microemboli during cardiopulmonary bypass are the principal cause of cognitive deficits after coronary bypass grafting. We have previously demonstrated that the majority of cerebral emboli occur during perfusionist interventions (ie, during the injection of air into the venous side of the cardiopulmonary bypass circuit). The purpose of this study was to determine whether an increase in perfusionist interventions is associated with an increased risk of postoperative cognitive impairment. METHODS: Patients undergoing elective coronary artery bypass grafting (n = 83) underwent a battery of neuropsychologic tests preoperatively and 3 months postoperatively. Patients were divided into 2 groups according to the median value of perfusionist interventions during cardiopulmonary bypass. Group 1 patients (n = 42) had fewer than 10 perfusionist interventions, and group 2 patients (n = 41) had 10 or more interventions. RESULTS: The 2 groups of patients were similar for all preoperative, intraoperative, and postoperative variables, with the exception of longer cardiopulmonary bypass times in group 2 patients (P <.001). Group 2 patients had lower mean scores on 9 of 10 neuropsychologic tests, with 3 (Rey Auditory Verbal Learning, Digit Span, and Visual Span) being statistically significant. Group 2 patients had worse cognitive test scores, even when controlling for increased bypass times. Group 2 patients had a nonsignificant trend toward an increased prevalence of neuropsychologic impairment 3 months postoperatively. CONCLUSIONS: Introduction of air into the cardiopulmonary bypass circuit by perfusionists, resulting in cerebral microembolization, may contribute to postoperative cognitive impairment.

Cardiopulmonary Bypass↗

Methylation of the protein phosphatase 2A catalytic subunit is essential for association of Balpha regulatory subunit but not SG2NA, striatin, or polyomavirus middle tumor antigen.

Binding of different regulatory subunits and methylation of the catalytic (C) subunit carboxy-terminal leucine 309 are two important mechanisms by which protein phosphatase 2A (PP2A) can be regulated. In this study, both genetic and biochemical approaches were used to investigate regulation of regulatory subunit binding by C subunit methylation. Monoclonal antibodies selectively recognizing unmethylated C subunit were used to quantitate the methylation status of wild-type and mutant C subunits. Analysis of 13 C subunit mutants showed that both carboxy-terminal and active site residues are important for maintaining methylation in vivo. Severe impairment of methylation invariably led to a dramatic decrease in Balpha subunit binding but not of striatin, SG2NA, or polyomavirus middle tumor antigen (MT) binding. In fact, most unmethylated C subunit mutants showed enhanced binding to striatin and SG2NA. Certain carboxy-terminal mutations decreased Balpha subunit binding without greatly affecting methylation, indicating that Balpha subunit binding is not required for a high steady-state level of C subunit methylation. Demethylation of PP2A in cell lysates with recombinant PP2A methylesterase greatly decreased the amount of C subunit that could be coimmunoprecipitated via the Balpha subunit but not the amount that could be coimmunoprecipitated with Aalpha subunit or MT. When C subunit methylation levels were greatly reduced in vivo, Balpha subunits were found complexed exclusively to methylated C subunits, whereas striatin and SG2NA in the same cells bound both methylated and unmethylated C subunits. Thus, C subunit methylation is critical for assembly of PP2A heterotrimers containing Balpha subunit but not for formation of heterotrimers containing MT, striatin, or SG2NA. These findings suggest that methylation may be able to selectively regulate the association of certain regulatory subunits with the A/C heterodimer.

3T3 Cells↗

Probing the mechanism of transport and compartmentalisation of polyamines in mammalian cells.

BACKGROUND: Many mammalian cells possess an active polyamine uptake system but little is known about the molecular mechanism of this transporter. The fate of polyamines taken up from the medium and the relationship to polyamine homeostasis remains to be fully established. The aim of this study was to develop a range of modified polyamines, particularly ligands incorporating a fluorophore, to explore the structural tolerances of the polyamine transport system and to probe the intracellular location of polyamines acquired from the medium. RESULTS: We synthesised a wide range of polyamine analogues incorporating cytotoxic agents, fluorescent chromophores and bulky substituents. All of these analogues have been shown to be good competitive inhibitors of spermidine uptake in a range of mammalian cells. Direct evidence for uptake of the fluorescent polyamine analogues and their subcellular distribution was obtained from confocal laser scanning fluorescence microscopy, which showed that they accumulated in granular structures within the cytoplasm and not in the nucleus. We demonstrated that their uptake is through the polyamine transport system by showing that pretreatment with DFMO, a potent inhibitor of polyamine biosynthesis, led to enhanced uptake, and cells deficient in the polyamine transport system did not accumulate these polyamine analogues. CONCLUSIONS: The polyamine transport system has a surprisingly broad structural tolerance. Fluorophore-containing polyamine analogues derived from the extracellular pool are located in granular structures within the cytoplasm and not to any great extent in the nuclei of mammalian cells. These observations might be consistent with a mechanism involving receptor-mediated endocytosis, and the granular 'structures' seen might reflect polyamine compartmentalisation within vesicles.

Animals↗

The case of the amnesic intelligence officer.

This paper describes a patient whose amnesia for an offence (fraud) and two fugue episodes occurred against the background of an underlying organic amnesia. The fugue states conformed in their duration and precipitating factors to previous accounts in the literature. The organic, anterograde memory impairment was attributed to multiple small infarcts and a larger infarction in the left medial temporal lobe, which were evident on MRI and PET scans after the patient had developed transient neurological signs. At follow-up, the anterograde amnesia had persisted, and the patient also showed some difficulty in retrieving autobiographical memories of past incidents or events, although other aspects of his retrograde memory were intact (including his knowledge of facts about his past life and his general knowledge of public events). The difficulty in retrieving autobiological incidents may have resulted from the presence of a moderate degree of frontal lobe dysfunction or, just possibly, from ischaemia in the left anterior temporal lobe. The persistence of the organic memory impairment and the importance of both the clinical history and neuropsychological testing in assessment are discussed, as well as the need to examine for possible organic factors in patients who may initially appear to manifest purely 'psychogenic' memory loss.

Accounting↗

On the existence of independent explicit and implicit learning systems: an examination of some evidence.

Hayes and Broadbent (1988), among others, have proposed that there are two independent systems of learning in humans. In their theory, they postulate that the explicit learning system gives rise to knowledge that is verbally describable, whereas the implicit learning system deals with knowledge that is not amenable to verbal report. Hayes and Broadbent presented data that they claimed supports a distinction between these two systems of learning. Their experiments involved the performance of subjects on two superficially similar tasks, and their claim was that one of the tasks induced learning in the explicit system, and the other induced learning in the implicit system. However, in five experiments here, we failed to find any convincing support for their empirical or theoretical claims. Our results suggest that the two tasks do not differ by inducing different types of learning, but simply differ in their degree of difficulty.

Adult↗

Driver fatalities and DUI offenders in New Jersey.

Comparisons of driving and demographic characteristics were made on 407 driver fatalities (DFs) and 407 motorists convicted of driving under the influence (DUI). Significantly more DUI offenders (DOs) than DFs were men and had previous DUIs, accidents, license suspensions, and weekend "index" events. DFs with a blood or brain alcohol concentration (BAC) of 100 or above mg/dL matched most closely with DOs on negative driving events, "index" event days, and demographics. Conversely, DFs with negative BACs differed significantly with DOs on virtually all characteristics. High-BAC DFs and DOs may well be drawn from the same subpopulation of deviant drivers, whereas DFs with negative BACs seem similar to licensed drivers in general.

Accidents, Traffic↗

The effects of combining sanctions and rehabilitation for driving under the influence: an evaluation of the New Jersey Alcohol Countermeasures Program.

In contrast to many other state Driving under the Influence (DUI) programs developed in the United States in the 1970s as alternatives to traditional sanctions, the New Jersey Alcohol Countermeasures Program combined sanctions with mandatory education/rehabilitation for offenders. Three components were evaluated: DUI education, "treatment," and Alcoholics Anonymous. For 2,734 first and repeat offenders participating in this program between 1979 and 1982, the program was effective in reducing DUI recidivism for program completers (66% while licensed and 51% while suspended) compared with noncompleters, but it was less effective in reducing subsequent moving violations while licensed (20% compared with noncompleters) and accidents while licensed (18% compared with noncompleters). Completers had higher rates of violations and accidents while suspended (9% compared with noncompleters). A small group of repeat offenders, missassigned to DUI education, had higher post conviction rates of negative driving events than those of comparable offenders assigned to "treatment" or Alcoholics Anonymous, indicating that for these offenders the latter interventions were more effective.

Alcohol Drinking↗

ABO blood groups in hematologic malignancies.

This article examines the genetic predisposition of individuals to lymphoma and leukemia with regard to the ABO blood groups. Blood samples from 558 patients suffering from various forms of lymphoma and leukemia were collected and typed for ABO blood groups. The ABO blood group phenotype frequencies of lymphoma patients were similar to those in control samples. Among leukemia patients, a significant increase in the frequency of the A2 phenotype was found in chronic lymphocytic leukemia. Possible mechanisms underlying the predisposition of individuals with the A2 blood group to chronic lymphocytic leukemia suggested by these preliminary results are discussed.

ABO Blood-Group System↗

Passive smoking and middle ear effusions in children of British servicemen in West Germany--a point prevalence survey by clinics of outpatient attendance.

Three hundred and twenty eight children of British servicemen serving in West Germany were studied in order to ascertain any relationship between parental smoking and the presence of middle ear effusion. The age range of the children was 18 months to 8 years. A questionnaire was completed by the parents of each child, and clinical examination and audiological tests demonstrated the presence or otherwise of middle ear effusions. One hundred and sixty four patients who had been referred with otological symptoms to the Ear, Nose and Throat Out Patient Department (ENT OPD) were surveyed, as were 164 other patients drawn from the Paediatric, Orthopaedic and Ophthalmic Out Patient Departments (OPDs) at BMH Rinteln. These 2 groups had similar age and sex distributions. The presence of middle ear effusions amongst children attending the ENT OPD was strongly associated with maternal cigarette smoking. This finding implies that mothers should not smoke at all in the same living accommodation as that used by their children. Paternal cigarette smoking showed no significant association with the presence of middle ear effusions.

Ambulatory Care↗

Management of traumatic rupture of the globe in aphakic patients.

We report the successful treatment of three cases of traumatic ruptures of the globe complicated by massive choroidal hemorrhage, uveal prolapse and retinal detachment. All three of the eyes were aphakic prior to injury and all patients were age 64 or older. The presenting visual acuity in all patients was light perception. The blunt injury in each case caused a wound dehiscence at the site of previous cataract extraction. All injuries were associated with uveal prolapse. Secondary surgical intervention was performed when the hemorrhagic choroidal detachments had decreased as demonstrated by echography in the suprachoroidal space, occurring at an average of 14 days after injury. The management consisted of surgical drainage of the choroidal hemorrhage combined with vitrectomy and silicone oil injection. Successful reattachment of the retina was achieved in all cases. Postoperative epiretinal membranes formed in two cases but all were anatomically successful at six months. Final visual acuities varied from 20/70 to 1/200, visual acuity being a function of secondary contusive damage to the retina and choroid. We believe that in eyes sustaining severe blunt injuries resulting in rupture of the globe complicated by massive choroidal hemorrhage and retinal detachment, properly timed external drainage of the choroidal hemorrhage combined with pars plana vitrectomy and silicone oil injection is a useful approach.

Aged↗

Poly-HEMA sponge: a biocompatible calcification implant.

Poly-hydroxyethyl methacrylate (Poly-HEMA) was investigated for biocompatibility and calcification potential. S.C. and I.M. implants and transplants to subperiosteal sites were examined. The material was judged to be tolerated by the host tissue since no inflammatory or degenerative changes were observed. This study established that calcification does occur. This calcification does not simulate bone formation; osteoblasts were not observed. The x-ray diffraction pattern resembles that of calcium hydroxyapatite.

Acrylic Resins↗