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Biomedical subjects

J Cooper

Publications and source records attributed to J Cooper.

At least 73 records · Page 4Linked to original sources
PubMed2000

Curative radiotherapy for anterior commissure laryngeal carcinoma.

There is continuing controversy surrounding the most effective treatment of glottic carcinoma involving the anterior commissure (AC). Surgery has been the preferred method of treatment, since studies previously indicated early tumor invasion of the thyroid cartilage at the AC, thereby assuming less curability by radiotherapy (RT). Subsequent laryngeal anatomic studies and refinement of RT techniques have brought into question the ineffectiveness of curative irradiation. A retrospective review of 174 patients with early-stage glottic carcinoma treated with standard fractionation curative RT revealed 34 patients with T1 and T2 lesions involving the AC. Allowing for a follow-up of at least 3 years, we observed only a 12% (4 of 34 patients) local recurrence rate after RT alone, with excellent voice quality and no major complications related to the irradiation. The 4 local recurrences were controlled by total laryngectomy, although 2 patients developed distant metastatic disease. Radiotherapy represents an effective method of treating T1 squamous cell carcinoma of the glottis with AC involvement. The small number of T2 glottic carcinomas in this study prevents a meaningful conclusion concerning treatment of these lesions.

Aged↗
PubMed2000

Selenium and immunocompetence in patients with head and neck cancer.

This randomized double-blind placebo-controlled study aimed to determine whether oral intake of 200 microg/d of sodium selenite, a dose within the safe and adequate daily intake (50-200 microg/d) recommended by the U.S. Food and Nutrition Board, will abrogate depressed or enhance normal-level immune functions of patients receiving therapy for squamous cell carcinoma of the head and neck. Subjects were given one selenium/placebo tablet/d for 8 wk, beginning on the day of their first treatment for the disease (e.g., surgery, radiation, or surgery and radiation) and their immune functions were monitored. Supplementation with selenium (Se) during therapy resulted in a significantly enhanced cell-mediated immunue responsiveness, as reflected in the ability of the patient's lymphocytes to respond to stimulation with mitogen, to generate cytotoxic lymphocytes, and to destroy tumor cells. The enhanced responsiveness was evident during therapy and following conclusion of therapy. In contrast, patients in the placebo arm of the study showed a decline in immune responsiveness during therapy, which was followed, in some patients, by an enhancement, but the responses of the group remained significantly lower than baseline values. The data also show that at baseline, patients entered in the study had significantly lower plasma Se levels than healthy individuals, and patients in stage I or II of disease had significantly higher plasma selenium levels than patients in stage III or IV of disease.

Adult↗
PubMed2000

A modified pure tone audiometry technique for medico-legal assessment.

A modified method of pure tone audiometry (PTA) in which the auditory threshold is approached from silence in ascending steps, with tone presentations of 1-4 seconds and interval durations of 1.5-5 seconds was assessed against the British Society of Audiology (BSA) method of PTA in terms of its ability to establish valid thresholds in cases of non-organic hearing loss, prevalent in medico-legal testing. The results reveal that the modified technique of PTA is a valid threshold measurement for honest subjects, and yields less non-organic overlay than the standard method of PTA in cases of non-organic hearing loss.

Adult↗
PubMed2000

Critical care bug team: a multidisciplinary team approach to reducing ventilator-associated pneumonia.

BACKGROUND: Ventilator-associated pneumonia rates in the medical-surgical intensive care unit first exceeded the 90th percentile in September 1997 and were significantly (P <.05) higher than National Nosocomial Infections Surveillance System pooled mean data. In January 1998, a multidisciplinary "Critical Care Bug Team" was developed by the Infection Control Committee to review 1997 National Nosocomial Infections Surveillance System data for four adult intensive care units in a 583-bed tertiary care hospital. METHODS: Membership included clinical nurse specialists, a dietitian, a pharmacist, a respiratory therapist, an infection control professional, a research specialist, and a physician adviser. Having the team report directly to the hospital's Infection Control and Adult Critical Care Committees maximized support for recommendations and provided a direct link from patient care to hospital administration. By identifying issues, evaluating patient care processes, performing literature searches, and monitoring compliance, the team implemented numerous interventions, including policy and procedure changes, purchasing of equipment, and implementation of various education tools. RESULTS: Each member of the Critical Care Bug Team contributed to a synergized effort that may have produced the desired outcome of decreasing ventilator-associated pneumonia rates. Except for August 1998, ventilator-associated pneumonia rates have been below the 75th percentile since May 1998. CONCLUSION: This study illustrates the effectiveness of a multidisciplinary team approach devised to reduce and stabilize ventilator-associated pneumonia rates in a medical-surgical intensive care unit.

Adult↗
PubMed2000

Intermittent exotropia: stimulus characteristics affect tests for retinal correspondence and suppression.

BACKGROUND AND PURPOSE: Prior studies have reported various sensory responses in subjects with intermittent exotropia [X(T)]. These varying responses have been proposed due to differences in stimulus targets, backgrounds, or even a lack of control of binocular alignment. This study investigated the effects of varying target and background stimuli while controlling binocular alignment. METHODS: Eight X(T)s of the divergence excess or basic type were presented dichoptic computer generated visual stimuli while an infra red eye movement monitoring system determined horizontal eye position of each eye. Target and background were varied to assess their effect on sensory responses during latent and manifest exotropia. RESULTS: Most of our X(T)s demonstrated, while tropic, a consistent, i.e., dominant, type of retinal correspondence, i.e. a response that occurred on most tests, independent of the stimulus or background used for testing. Four subjects demonstrated harmonious anomalous retinal correspondence (HARC) while three subjects demonstrated normal retinal correspondence (NRC) with three out of four of the tests. In two out of four stimuli used for testing, one subject demonstrated NRC and another HARC. CONCLUSIONS: Complex backgrounds resulted in the largest number of suppressions, whereas blank backgrounds decreased the number of reported suppressions.

Adaptation, Ocular↗
PubMed2000

The law and ethics of the use of experimental medication in patients incapable of expressing consent: between a rock and a hard place.

In Australia, human research ethics committees approve clinical trials of drugs in accordance with federal regulations. Federal guidelines allow for the possible conduct of clinical trials in all populations. Within the State of New South Wales, persons unable to consent because of disability are subject to State legislation which, until 1998, regarded drug trials as Special Medical Treatment requiring consent of the Guardianship Tribunal. That consent could only be given if an anticipated individual benefit could be proved. As no such guarantee could be given prior to conduct of a clinical trial, it being unethical to trial an active substance against a placebo if potential individual benefit is already proven for the active substance, a conundrum resulted whereby the Tribunal could not give the required approval. Many argued that the New South Wales law resulted in some experimental medications, such as those being available to minimise tissue damage following stroke, or those being specifically developed for those with late stage dementia, not being made available to their target populations. Amendments were made to remove reference to clinical drug trials as Special Medical Treatment, and a new system established whereby such trials could proceed, including the use of a placebo, with the approval of an ethics committee and the Tribunal.

Clinical Trials as Topic↗
PubMed1999

[Efficient learning with data from own practice--experiences from the SATS-project].

Between 1995 and 1998 the Norwegian Medical Association carried out a project to develop and assess a quality improvement tool for use in general practice (SATS). This method combines self-directed learning, documentation of practice and peer group support. SATS defined performance indicators for registration of practice by means of computerised patient records. Groups of four to ten general practitioners used their own consultation data as a basis for learning cycles. The practice evaluation indicates significant improvement in clinical work. Participating doctors found that having their own recorded data examined in a supportive peer environment was a major force for change. They reported satisfaction with the method, and expressed an interest in trying out new topics. However, the project demonstrated the need for simplification of terminology, further development of group process methods and computer software. There is also a need for strong local support of peer review groups.

Clinical Competence↗
PubMed1999

International Arctic Seas Assessment Project.

The International Atomic Energy Agency responded to the news that the former Soviet Union had dumped radioactive wastes in the shallow waters of the Arctic Seas, by launching the International Arctic Seas Assessment Project in 1993. The project had two objectives: to assess the risks to human health and to the environment associated with the radioactive wastes dumped in the Kara and Barents Seas; and to examine possible remedial actions related to the dumped wastes and to advise on whether they are necessary and justified. The current radiological situation in the Arctic waters was examined to assess whether there is any evidence for releases from the dumped waste. Potential future releases from the dumped wastes were predicted, concentrating on the high-level waste objects containing the major part of the radionuclide inventory of the wastes. Environmental transport of released radionuclides was modelled and the associated radiological impact on humans and the biota was assessed. The feasibility, costs and benefits of possible remedial measures applied to a selected high-level waste object were examined. Releases from identified dumped objects were found to be small and localised to the immediate vicinity of the dumping sites. Projected future annual doses to members of the public in typical local population groups were very small, less than 1 microSv--corresponding to a trivial risk. Projected future doses to a hypothetical group of military personnel patrolling the foreshore of the fjords in which wastes have been dumped were higher, up to 4 mSv/year, which still is of the same order as the average annual natural background dose. Moreover, since any of the proposed remedial actions were estimated to cost several million US$ to implement, remediation was not considered justified on the basis of potentially removing a collective dose of 10 man Sv. Doses calculated to marine fauna were insignificant, orders of magnitude below those at which detrimental effects on fauna populations might be expected to occur. Remediation was thus concluded not to be warranted on radiological grounds.

Animals↗
PubMed1999

Crystal structure of cardosin A, a glycosylated and Arg-Gly-Asp-containing aspartic proteinase from the flowers of Cynara cardunculus L.

Aspartic proteinases (AP) have been widely studied within the living world, but so far no plant AP have been structurally characterized. The refined cardosin A crystallographic structure includes two molecules, built up by two glycosylated peptide chains (31 and 15 kDa each). The fold of cardosin A is typical within the AP family. The glycosyl content is described by 19 sugar rings attached to Asn-67 and Asn-257. They are localized on the molecular surface away from the conserved active site and show a new glycan of the plant complex type. A hydrogen bond between Gln-126 and Manbeta4 renders the monosaccharide oxygen O-2 sterically inaccessible to accept a xylosyl residue, therefore explaining the new type of the identified plant glycan. The Arg-Gly-Asp sequence, which has been shown to be involved in recognition of a putative cardosin A receptor, was found in a loop between two beta-strands on the molecular surface opposite the active site cleft. Based on the crystal structure, a possible mechanism whereby cardosin A might be orientated at the cell surface of the style to interact with its putative receptor from pollen is proposed. The biological implications of these findings are also discussed.

Amino Acid Sequence↗
PubMed1999

Predictors of time loss after back injury in nurses.

STUDY DESIGN: A 2-year prospective inception cohort study of back injury in nurses. OBJECTIVES: To determine the extent to which characteristics of nurses, of the injury, and of the workplace predict occurrence and duration of time loss from work after back injury. SUMMARY OF BACKGROUND DATA: During 2 years, 320 nurses incurred 416 back injuries at a large teaching hospital in Winnipeg, Canada. Nurses injured on preselected wards were targeted for early intervention, including provision of modified work, whereas nurses injured on other wards received the usual care. METHODS: Time loss attributable to the back injury during the 6 months after injury was analyzed. Three statistical models were used to examine occurrence of time loss (logistic regression), duration of time loss (Tobit regression), and duration of time loss once an injury incurring time loss had been documented (least-squares regression). RESULTS: In 218 of the 416 injuries, the injured nurse consented to interview. Whereas perceived disability was related to whether a time loss injury would ensue, self-reported pain was strongly related to the duration of time loss once an injury had become a time loss injury. Duration of time loss was reduced by participation in the return-to-work program. Mechanism of injury, specifically injury occurring while lifting patients, resulted in greater time loss. CONCLUSIONS: Focusing on reducing the perception of disability at the time of injury is critical to preventing time loss, but once time loss has occurred, offer of modified work and attention to pain reduction are warranted. The findings add to the evidence that workplace-based intervention programs can be effective in reducing the morbidity resulting from back injury.

Accidents, Occupational↗
PubMed1999

Irradiation with or without misonidazole for patients with stages IIIB and IVA carcinoma of the cervix: final results of RTOG 80-05. Radiation Therapy Oncology Group.

PURPOSE: The purpose of this study was to evaluate tumor response, progression-free survival, local tumor control, patterns of relapse, and toxicity in patients with Stages IIIb and IVa squamous cell carcinoma of the uterine cervix treated with irradiation or irradiation and misonidazole. This is a report of the final results of the study. METHODS: This study was a prospective randomized Phase III trial performed by the Radiation Therapy Oncology Group (RTOG). Between August 1980 and November 1984, 120 patients with Stages IIIb and IVa squamous cell carcinoma of the cervix were randomized to receive either standard irradiation or standard irradiation and misonidazole. Irradiation consisted of 46 Gy to the pelvis plus a 10 Gy parametrial boost followed by intracavitary brachytherapy or external irradiation boost to the primary tumor. Misonidazole was administered at 400 mg/m2 daily, 2-4 h before irradiation. Patients in the 2 treatment groups were evenly distributed by stage, Karnofsky Performance Status, and positive para-aortic lymph nodes. RESULTS: Sixty-one patients were treated with irradiation alone, and 59 patients received irradiation and misonidazole. Complete response in the pelvis occurred in 44 (75%) of those treated with irradiation and in 38 (64%) of those treated with irradiation and misonidazole. The progression-free survivals were 22% at 5 years for the control group, and 29% at 5 years for the misonidazole group. At the time of last follow-up, 18 patients in the control arm were free of disease, and in the experimental arm, 19 were free of disease. The patterns of failure for those treated with irradiation alone were local-only in 9 patients, distant-only in 8 patients, and local and distant in 11 patients. The patterns of failure for those receiving irradiation and misonidazole were local-only in 3 patients, distant-only in 8 patients, and local and distant in 8 patients. The maximum toxicity experienced per patient was grade 3 in 18%, grade 4 in 8%, and no grade 5 toxicity for those treated with irradiation alone compared to 8%, 2%, and 2%, respectively, for the experimental arm. CONCLUSION: There were no statistically significant differences in pelvic response, disease-free survivals, patterns of failure, or toxicity for the irradiation alone group or for the irradiation and misonidazole group as administered in this study for patients with Stages IIIb and IVa squamous cell carcinoma of the uterine cervix.

Adult↗
PubMed1999

Human platelets exclusively bind oxidized low density lipoprotein showing no specificity for acetylated low density lipoprotein.

The widely studied macrophage scavenger receptor system is known to bind both acetylated low density lipoprotein and oxidized low density lipoprotein. Although only the latter ligand has been shown to occur in vivo, acetylated low density lipoprotein is often used to evaluate the contribution of scavenger receptors to different (patho)physiologic processes, assuming that all existing subtypes of scavenger receptors recognise both lipoproteins. In the present work, we identify human platelets as the first natural cell type to bind oxidized low density lipoprotein without showing specificity for acetylated low density lipoprotein. Consequently, platelets possess exclusive receptor(s) for oxidized low density lipoprotein distinct from the 'classical' scavenger receptor AI/AII. From the data presented in this work, we conclude that the class B scavenger receptor CD36 (GPIV) is responsible for this exclusive oxidized low density lipoprotein binding.

Animals↗
PubMed1999

Three-dimensional imaging by deconvolution microscopy.

Deconvolution is a computational method used to reduce out-of-focus fluorescence in three-dimensional (3D) microscope images. It can be applied in principle to any type of microscope image but has most often been used to improve images from conventional fluorescence microscopes. Compared to other forms of 3D light microscopy, like confocal microscopy, the advantage of deconvolution microscopy is that it can be accomplished at very low light levels, thus enabling multiple focal-plane imaging of light-sensitive living specimens over long time periods. Here we discuss the principles of deconvolution microscopy, describe different computational approaches for deconvolution, and discuss interpretation of deconvolved images with a particular emphasis on what artifacts may arise.

Artifacts↗
PubMed1999

Increased apoptosis of Huntington disease lymphoblasts associated with repeat length-dependent mitochondrial depolarization.

Huntington disease (HD) is a genetically dominant condition caused by expanded CAG repeats coding for glutamine in the HD gene product huntingtin. Although HD symptoms reflect preferential neuronal death in specific brain regions, huntingtin is expressed in almost all tissues, so abnormalities outside the brain might be expected. Although involvement of nuclei and mitochondria in HD pathophysiology has been suggested, specific intracellular defects that might elicit cell death have been unclear. Mitochondria dysfunction is reported in HD brains; mitochondria are organelles that regulates apoptotic cell death. We now report that lymphoblasts derived from HD patients showed increased stress-induced apoptotic cell death associated with caspase-3 activation. When subjected to stress, HD lymphoblasts also manifested a considerable increase in mitochondrial depolarization correlated with increased glutamine repeats.

Adolescent↗
PubMed1999

Present and future possibilities for defining a phenotype for specific language impairment.

This brief report summarizes a workshop that was held at the National Institutes of Health in April 1998. The goal of the workshop was to further the development of a definition for the phenotype of specific language impairment (SLI). The report includes a discussion of research recommendations that will refine our current views of the definition of the SLI phenotype and sets out priority areas that are in need of further study to help advance understanding of this complex language-based disorder.

Forecasting↗