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Biomedical subjects

T Bell

Publications and source records attributed to T Bell.

At least 19 recordsLinked to original sources
PubMed2004

Myocardial necrosis in a captive binturong (Arctictis binturong).

An adult male binturong, Arctictis binturong, which had been anorexic and lethargic for seven days became acutely dyspnoeic and died under anaesthesia. A postmortem examination revealed left ventricular hypertrophy with a thrombus occluding the left ventricular chamber. Histological findings included moderate to severe multifocal, vasculocentric myocardial degeneration and necrosis with fibrosis replacing myocardiocytes. Escherichia coli and Proteus mirabilis were grown on cultures. The animal's serum vitamin E and selenium levels were considered adequate. The aetiology of the chronic myocardial changes could not be determined.

Animals↗
PubMed2002

Recognition of ST elevation by paramedics.

OBJECTIVE: To define the ability of UK paramedics to recognise ST segment elevation using a prehospital 12 lead electrocardiogram (ECG). METHODS: Analysis of the diagnostic ability of seven paramedics 12 months after a two day training course, using interpretation of a 12 lead ECG by two cardiologists as the criterion standard. Comparison of paramedic and A&E SHO diagnosis to determine accuracy, specificity, sensitivity, negative predictive value, and positive predictive value of paramedic interpretation. RESULTS: Paramedics showed a median accuracy of 0.95 (95% CI 0.88 to 0.98), a specificity of 0.91 (95% CI 0.53 to 1.0), a sensitivity of 0.97 (95% CI 0.94 to 0.99), a NPV of 0.77 (95% CI 0.62 to 0.92) and a PPV of 0.99 (95% CI 0.92 to 1.0). This was not significantly different from a group of experienced A&E SHOs. CONCLUSIONS: UK paramedics can recognise ST elevation using a 12 lead ECG. Radio transmission of an ECG may not be necessary to pre-alert the hospital.

Clinical Competence↗
PubMed2001

SCID in Jack Russell terriers: a new animal model of DNA-PKcs deficiency.

We recently described the incidence of a SCID disease in a litter of Jack Russell terriers. In this study, we show that the molecular defect in these animals is faulty V(D)J recombination. Furthermore, we document a complete deficit in DNA-dependent protein kinase activity that can be explained by a marked diminution in the expression of the catalytic subunit DNA-dependent protein kinase catalytic subunit (DNA-PKcs). We conclude that as is the case in C.B-17 SCID mice and in Arabian SCID foals, the defective factor in these SCID puppies is DNA-PKcs. In mice, it has been clearly established that DNA-PKcs deficiency produces an incomplete block in V(D)J recombination, resulting in "leaky" coding joint formation and only a modest defect in signal end ligation. In contrast, DNA-PKcs deficiency in horses profoundly blocks both coding and signal end joining. Here, we show that although DNA-PKcs deficiency in canine lymphocytes results in a block in both coding and signal end joining, the deficit in both is intermediate between that seen in SCID mice and SCID foals. These data demonstrate significant species variation in the absolute necessity for DNA-PKcs during V(D)J recombination. Furthermore, the severity of the V(D)J recombination deficits in these three examples of genetic DNA-PKcs deficiency inversely correlates with the relative DNA-PK enzymatic activity expressed in normal fibroblasts derived from these three species.

Alleles↗
PubMed2001

Forgetting our facts: the role of inhibitory processes in the loss of propositional knowledge.

Seven experiments are reported that show that retrieving facts from long-term memory is accomplished, in part, by inhibitory processes that suppress interfering facts. When asked to repeatedly retrieve a recently learned proposition (e.g., recalling The actor is looking at the tulip, given cues such as Actor looking t__), subjects experienced a recall deficit for related facts (e.g., The actor is looking at the violin) on a recall test administered 15 min later. Importantly, this retrieval-induced forgetting was shown to generalize to other facts in which the inhibited concepts took part (e.g., The teacher is lifting the violin), replicating a finding observed by M. C. Anderson and B. A. Spellman (1995) with categorical stimuli. These findings suggest a critical role for suppression in models of propositional retrieval and implicate the mere retrieval of what we know as a source of forgetting of factual knowledge.

Adult↗
PubMed2001

Can nurses govern in a government agency?

A shared governance model was implemented within the nursing service of the Durham Veterans Affairs Medical Center in 1997. In 1999, members of the Nursing Quality/Staff Education/Research Council examined facility nurses' perceptions of governance to determine the degree to which the model had been implemented. Results of the study indicate that although imperatives at the organizational level were incompatible with three aspects of shared governance, there were three shared governance dimensions pertaining to basic nursing practice that reached or surpassed governance thresholds. This study highlights the potential of nursing management innovation within highly bureaucratic organizations.

Academic Medical Centers↗
PubMed2001

Evaluation of a model of intervention to create a visually enriched environment.

Within a day resource for people with learning disabilities 'stand-alone' signing training proved ineffectual to sustain lasting change in the formalised gestural behaviours of carers. Consideration was given to setting conditions pre- and post-training and a new model of delivery evolved, designed in partnership with day resource staff. Aims of intervention were to promote the adoption and active use of signing as an aid to communication and move towards a partnership framework which values the role of carers as co-facilitators and lessens dependency on the therapist. This paper describes and evaluates a training model which was found to be successful in translating knowledge into changes in practice and discusses the critical factors which should be built into future interventions.

Caregivers↗
PubMed2001

Biological correlates of acute hypersensitivity events with DAB(389)IL-2 (denileukin diftitox, ONTAK) in cutaneous T-cell lymphoma: decreased frequency and severity with steroid premedication.

DAB(389)IL-2 (denileukin diftitox, ONTAK) is a cytokine-targeted fusion protein that delivers the catalytic domain of diphtheria toxin to lymphoma cells expressing the interleukin-2 receptor (IL-2R). In phase I and phase III studies of DAB(389)IL-2 in patients with cutaneous T-cell lymphoma (CTCL), non-Hodgkin's lymphoma, and Hodgkin's disease in which premedications were limited to diphenhydramine and acetaminophen, acute infusion-related hypersensitivity reactions occurred in 70% of patients and vascular leak syndrome (VLS) in 27%, resulting in discontinuation of therapy in 29% of patients. There was no correlation between the dose or half-life of DAB(389)IL-2 and the occurrence of hypersensitivity events or VLS. To explore whether steroid premedication would improve the tolerability of DAB(389)IL-2, we treated 15 patients with CTCL with either dexamethasone or prednisone prior to each dose of DAB(389)IL-2. The incidence of acute infusion events was significantly decreased, with only three patients experiencing acute infusion events (one grade 4) and only two patients developing clinically apparent VLS. Grade 3 skin rash occurred in two patients and moderately severe asthenia in nine patients. A significantly improved response rate of 60% was noted with the use of steroid premedication compared to prior studies in which steroids were prohibited. We conclude that steroid premedication significantly improves the tolerability of DAB(389)IL-2 without compromising the clinical response.

Adult↗
PubMed2001

Genetic material is present in cadaveric dermis and cadaveric fascia lata.

PURPOSE: We determined whether genetic material is present in the commercially processed cadaveric allografts used in sling surgery. MATERIALS AND METHODS: We evaluated 16 samples from 2 commercial sources of human allograft, including 8 each of freeze-dried gamma irradiated cadaveric fascia lata and acellular cadaveric dermis. Fresh human rectus fascia and sterile saline served as positive and negative controls, respectively. All samples underwent a standard proteinase K/sodium dodecyl sulfate/phenol extraction technique to isolate DNA. Polymerase chain reaction was done to amplify the retrieved DNA material, spectrophotometry to quantify DNA concentration and agarose gel electrophoresis to determine the size of DNA fragments. RESULTS: Of the 16 samples tested from 2 commercial sources of human allograft fascia 14 (87.5%) contained DNA. Mean DNA concentration plus or minus standard error was 258.3 +/- 80.1 and 272.8 +/- 168.8 microg./gm. tissue for cadaveric fascia lata and cadaveric dermis, respectively. Polymerase chain reaction amplified DNA segments of 2,000 bp from 1 of each of the 8 samples of cadaveric fascia lata and cadaveric dermis. CONCLUSIONS: Freeze-dried gamma irradiated cadaveric fascia lata and acellular cadaveric dermis contained intact DNA.

Bioprosthesis↗
PubMed2000

Surface hardness changes induced by O-, Ca- or P-ion implantation into titanium.

Titanium or titanium alloys are very attractive biomedical materials. Biocompatible elements of oxygen, calcium and phosphorus were implanted into titanium and changes of surface hardness were measured using an ultra micro indenter (UMIS-2000). A multiple load-partial unload procedure that can reveal a hardness versus depth profile was adopted. Depth profiles of concentration of implanted ions were obtained by SIMS measurement. For O and P implantation, it is observed that the hardness increases with the increases in the dose. O implantation produced the largest increase in hardness, up to 2.2 times higher than the unimplanted titanium. On the other hand, Ca implantation produced only a small increase in the hardness that was independent of the ion dose. The surface oxide layer of a Ca implanted titanium sample was much thicker than the unimplanted samples or those implanted with O and P ions. The depth of maximum hardness increases with increasing energy of implanted ions. The depths of the maximum hardness occur at indentation depths of one-third to one-eighth of the mean ranges of implanted ions.

Journal Article↗
PubMed2000

Choice of antibiotic and risk of colonization with vancomycin-resistant Enterococcus among patients admitted for treatment of community-acquired pneumonia.

A time-series prospective study of patients admitted to the hospital for treatment of community-acquired pneumonia was undertaken to determine vancomycin-resistant enterococcal perianal colonization rates among patients who received ceftriaxone with or without erythromycin versus those who received levofloxacin. A colonization rate of 16% (8/51) was found in the ceftriaxone-erythromycin group versus 0% (0/52) in the levofloxacin group .

Adolescent↗
PubMed1999

Eyelid resurfacing.

BACKGROUND AND OBJECTIVE: Laser resurfacing of eyelids was examined in a series of experiments designed to measure beam parameters, surface temperatures, ablation characteristics, thermal damage, tissue responses and clinical outcomes. These data were collected for the purpose of developing a logical basis for clinical dosimetry. STUDY DESIGN: All experiments were conducted with similar short-pulse CO(2) lasers (TruPulse, Albuquerque, NM) where the beam had been carefully characterized and calibrated. The chronological sequence examined begins with the photophysical laser/tissue interactions during the first few microsec of irradiation and ends with an evaluation of the efficacy of wrinkle reduction nine months after treatment. RESULTS: Eyelid tissue removed by the first and second passes consisted mostly of epidermis with about 38 microm of thermal damage into the papillary dermis. Erythema resolved within four weeks and most patients experienced 70-100% wrinkle reduction by nine months. CONCLUSION: A layer of contracted dermal scar tissue that replaced the thermally challenged zone in the dermis is identified as the substrate for wrinkle reduction. The data support the following dosimetry for periorbital wrinkle reduction: One pass 4-6 J/cm(2) (350-500 mJ into a 3 x 3 mm spot). A second treatment after 9-12 months may be more beneficial than a second pass.

Animals↗
PubMed1999

Helical CT of abdominal trauma.

CT has revolutionized the diagnostic work-up of trauma patients with suspected abdominal injuries. A wide range of intraperitoneal and retroperitoneal organ injuries can be quickly and accurately diagnosed with CT. Today, helical CT technology permits even faster examinations, with improved intravenous contrast opacification of parenchymal organs and vascular structures and reduced CT artifacts caused by patient motion, respiration, and arterial pulsation. Severely injured and potentially unstable patients, who might not have been able to tolerate the long CT examinations of the past, may be quickly evaluated today with helical CT. Accurate diagnosis requires high quality CT examinations that are performed with optimum CT protocols. This article reviews the currently recommended helical CT protocols for evaluating patients with suspected abdominal injuries, and the CT findings when injuries are present.

Abdominal Injuries↗
PubMed1999

Role of motor unit number estimate electromyography in experimental canine laryngeal reinnervation.

Laryngeal electromyography has been used clinically to differentiate neuromuscular pathology from other causes of vocal fold immobility such as arytenoid dislocation, tumor invasion, or cricoarytenoid joint fixation. Electromyography has also been used to predict the prognosis for nerve recovery in laryngeal paralysis. Existing electromyographic techniques either record activity with voluntary motion or study nerve conduction. In this study a new technique, motor unit number estimation, a commercially available quantitative method of electromyographic analysis, is used to study the progress of recovery of vocal fold function after recurrent laryngeal nerve injury. Four dogs underwent transection and immediate reanastomosis of selected branches of the adductor and abductor branches of the recurrent laryngeal nerve on 1 side; the opposite side served as a control. Baseline electromyographic and videolaryngoscopic studies were performed. These measures were then repeated in a longitudinal fashion every 6 weeks after denervation. The motor unit number estimation technique indicated a return of motor unit numbers with time, along with estimates of their size. This was consistent with the expected progress of laryngeal reinnervation. These data and their predictive value for nerve recovery will be discussed.

Anastomosis, Surgical↗
PubMed1999

MTHFR (C677T) polymorphisms and stage III colon cancer: response to therapy.

BACKGROUND: Leucovorin and 5-fluorouracil (5-FU) chemotherapeutics are often used as coinhibitors of the thymidylate synthase pathway to thwart the growth of cancer cells in certain types of neoplasms. The metabolism of leucovorin is mediated through the enzyme methylenetetrahydrofolate reductase (MTHFR). A common polymorphism in the MTHFR gene has been reported to be responsible for as much as a 70% reduction in activity of this enzyme when present in the homozygous form. METHODS AND RESULTS: A total of 51 stage III colon cancer patients were identified through our tumor registry. Non-neoplastic, archived tissue was obtained for each patient and subjected to MTHFR C677T PCR-RFLP genotyping. The MTHFR C677T allele was present in 32 patients (28 heterozygotes and 4 homozygotes). The remaining 19 patients carried only the wild-type allele. Overall survival was 42.10% (8/19) for wild types and 43.757% (14/32) for those with at least one C677T allele. Of the four homozygotes identified, three have succumbed to their cancer and one is alive with cancer. CONCLUSIONS: We were unable to demonstrate a survival difference between those stage III colon cancer patients receiving leucovorin therapy that carried the MTHFR C677T allele and those that were wild type for this allele. The results of this study suggest that certain subgroups (ie, homozygotes) of patients may benefit from genotypic analysis of the MTHFR gene.

Alleles↗
PubMed1999

Women's experiences of obtaining emergency contraception: a phenomenological study.

Emergency contraception (EC) has been available since 1984 but has been labelled the 'best kept secret' (Winfield, 1995). Because EC was originally termed 'the morning after pill', many people interpreted this literally and missed an opportunity to use the method. More recent publicity has dropped this term and emphasized that the method is effective up to 72 h after unprotected intercourse or contraceptive failure (Burton & Salvage, 1990). Uptake of EC has steadily increased since 1985 but there is still evidence that younger women in particular are least aware of its existence.

Adolescent↗
PubMed1999

Management of blunt splenic trauma in patients older than 55 years. Southern Connecticut Regional Trauma Quality Assurance Committee.

BACKGROUND: Many experts have suggested that blunt splenic trauma in patients older than 55 years should not be managed by observation because of supposed increased fragility of the spleen and decreased physiologic reserve in elderly patients. We sought to determine the outcome of nonoperative management of blunt splenic trauma in patients older than 55 years. METHODS: For the years 1994 through 1996, data for patients with splenic injury older than 55 years from seven trauma centers in a single state were reviewed. RESULTS: Blunt splenic trauma occurred in 41 patients older than 55 years. Eight patients were excluded from further analysis because of death from massive associated injuries within 24 hours of admission. The remaining 33 patients (mean age, 72+/-10 years) were divided into two groups: immediate exploration (10 patients) and observation (23 patients). Observation of blunt splenic injury failed in 4 of 23 patients (17%). No patient deaths were related to the method of management of the splenic injury. CONCLUSIONS: Observation of the elderly patient with blunt splenic trauma has an acceptable failure rate of 17%.

Age Factors↗
PubMed1998

Desquamin is an epidermal ribonuclease.

Desquamin is a glycoprotein that we have isolated from the upper granular layer and the stratum corneum of human epidermis; it is not ordinarily expressed in submerged cultures, whose terminal differentiation stops short of formation of these layers. The exogenous addition of desquamin to human cultured keratinocytes extended their maturation, and hematoxylin staining indicated a loss of cell nuclei. For confirmation, cultured cells were lysed in situ, and the nuclei were incubated with desquamin for several days, then stained with hematoxylin. Damage to the nuclei was evident: the nuclear inclusions remained intact, while the surrounding basophilic nuclear matrix was degraded. Desquamin was then tested directly for nuclease activity. Ribonuclease activity was determined by incubating desquamin with human epidermal total RNA and monitoring the dose-dependent disappearance of the 28S and 18S ribosomal RNA bands in an agarose/formaldehyde gel. On RNA-containing zymogels, we confirmed the RNase activity to be specific to desquamin. Using synthetic RNA homopolymers, we found the active RNase domains to be limited to cytosine residues. On the contrary, DNA was not degraded by an analogous procedure, even after strand-separation by denaturation.

Cell Adhesion Molecules↗