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Biomedical subjects

D Taylor

Publications and source records attributed to D Taylor.

At least 145 records · Page 8Linked to original sources
PubMed1999

Safe mobilization of normal progenitors in advanced chronic myeloid leukemia with intensive chemotherapy and granulocyte-colony stimulating factor.

Twenty-one patients with advanced chronic myeloid leukemia (late chronic phase (n = 8), accelerated phase (n = 11) and blast crisis (n = 2)) were treated with idarubicin, cytarabine, and etoposide followed by G-CSF and subsequent collection of peripheral blood progenitor cells in the early recovery phase. Treatment was reasonably well tolerated with no deaths or intensive care admissions. Despite the advanced phase of disease and heavy pretreatment with cytotoxics and interferon-alfa, 11 of 21 patients (52%) achieved a cytogenetic response. Of the nine major cytogenetic responses (complete (n = 3) and partial (n = 6)), seven achieved adequate progenitor collections for consideration for autologous transplantation. The only predictor of response was disease duration (P = 0.02). With a median follow-up of 1171 days from treatment it appears unlikely that G-CSF contributed to disease progression. Survival post-IcE was predicted by disease stage (P = 0.0001). Intensive chemotherapy followed by G-CSF allowed adequate yields of predominantly Philadelphia chromosome negative progenitor cells to be obtained from one-third of patients with advanced CML.

Adult↗
PubMed1999

Iatrogenic drug dependence--a problem in intensive care? Case study and literature review.

Use of sedative and analgesic pharmacological agents is a widespread practice in intensive care units (ICUs). Mainly, this involves opioid and benzodiazepine analogues, both known to induce dependence/tolerance states. This paper is based on a clinical scenario in which a patient treated with these agents developed problems when they had been discontinued, and exploration of the extent of such problems generally. The problems range across a wide range of domains and may include physical discomfort, difficulty weaning from respiratory assistance and the drugs, and the problems of short- and long-term psychological distress. Although there may be a recognition that these drugs can typically cause dependence problems, little emphasis has traditionally been given to assessing these problems in ICUs. Yet the ICU may be an area where these drugs are used in high volumes. The recognition, physiology, management and prevention of iatrogenic drug dependence/tolerance in critical care environments is elucidated, with reference to relevant literature.

Analgesics, Opioid↗
PubMed1999

Visual evoked potential evidence of albino-like chiasmal misrouting in a patient with Angelman syndrome with no ocular features of albinism.

An 8-month-old boy with global developmental delay, including visual and hearing inattention, was examined in the ophthalmic clinic. Monocular flash visual evoked potentials demonstrated a crossed asymmetry in scalp distribution, a feature considered to be pathognomic of albinism. Remarkably a foveal reflex was noted in each eye and this patient did not have nystagmus, iris transillumination, nor conspicuously pale fundi. The optic discs appeared normal. He was noted to have very fair skin and hair, with a small head and flat occiput. Cytogenetic studies demonstrated a microdeletion of the maternal chromosome 15q11-q13, and he was diagnosed with Angelman syndrome.

Albinism↗
PubMed1999

Congenital cataract and multisystem disorders.

A knowledge of those syndromes associated with congenital cataract is essential for the paediatric ophthalmologist, as congenital cataracts are manifest in a large number of syndromes. It is important to have the correct diagnosis in such cases, not only for genetic and prognostic information, but also in order to help the parents to understand their child's condition. This paper describes the more common syndromes seen in association with congenital cataract, and emphasises the importance of looking at the whole child and family. We aim to provide a practical clinical guide to the diagnosis of hereditary and non-hereditary syndromes associated with congenital cataract.

Abnormalities, Multiple↗
PubMed1999

Tissue-selective expression of dominant-negative proteins for the regulation of vascular smooth muscle cell proliferation.

The transcription factors c-myb and c-myc are essential for vascular smooth muscle cell (VSMC) replication and are rapidly induced following mitogenic stimulation of quiescent VSMCs in vitro and in vivo following balloon catheter injury. Consequently, interference with c-myb and c-myc function provides a possible avenue for the prevention of VSMC proliferation associated with intimal hyperplasia. We have carried out studies focused on the inhibition of VSMC proliferation using dominant-negative gene constructs incorporating the DNA-binding domains of the c-myb or c-myc genes fused to the repressor domain of the Drosophila engrailed gene. Transient transfection of rat, rabbit and human vascular SMCs results in a dramatic inhibition of proliferation for at least 72 h after transfection. Furthermore, this inhibition of cellular proliferation was found to be due, at least in part, to the induction of apoptosis. Coupling expression of the chimeric dominant-negative proteins to transcriptional regulatory elements of the human vascular smooth muscle alpha-actin gene allows specific targeting of vascular smooth muscle cells.

Actins↗
PubMed1999

An assessment of the use of intravesical potassium in the diagnosis of interstitial cystitis.

PURPOSE: We evaluated the use of intravesical potassium in the diagnosis of interstitial cystitis. MATERIALS AND METHODS: A blinded test assessment on 39 consecutive subjects attending our urology clinic for the evaluation of symptoms consistent with interstitial cystitis was performed. The pain response to intravesical potassium and water as a control was measured. The response rate was compared to the results of cystoscopy using standard outcome measures associated with diagnostic test assessment. RESULTS: The probability of having interstitial cystitis given a positive intravesical potassium test was 66%. This finding added no new useful information and would not be helpful with clinical decisions as the probability of having interstitial cystitis in this population was already 56% before the test. Similarly, if the test was negative then 46% or nearly half of the subjects were still likely to have interstitial cystitis. Therefore, a negative test would have no ability to rule out disease nor would it be useful in making clinical decisions about how to proceed with evaluation or therapy. Test characteristics were considered poor with a sensitivity of 69.5% and a specificity of 50%. Likelihood ratios (positive 1.39, negative 0.61) also indicated poor inclusion and exclusion capabilities. CONCLUSIONS: The general use of intravesical potassium as a diagnostic test for interstitial cystitis is not validated. The diagnosis of interstitial cystitis must depend on the clinical presentation and endoscopic findings based on National Institutes of Health criteria.

Administration, Intravesical↗
PubMed1999

Ultraviolet radiation-blocking characteristics of contact lenses: relevance to eye protection for psoralen-sensitised patients.

Nine brands of contact lens marketed as "UV protective" were tested for ultraviolet (UV) transmission in order to assess potential suitability for psoralen-sensitised patients. UV-transmission characteristics of hydrated lenses was tested with a Bentham monochromator spectro-radiometer system. All lenses showed minimal transmission loss in the visible band. The performance of the nine lenses was uniform for ultraviolet B radiation with negligible transmission, but showed variation in transmission for ultraviolet A radiation. None of the lenses complied with UV-transmission criteria used previously to assess UV-blocking spectacles. Only two lenses had UV-blocking characteristics which came close to the arbitrary criteria used. The performance of ordinary soft and hard lenses was very similar, with negligible blocking of UV radiation. None of the nine contact lenses marketed as "UV protective" excluded sufficient UVA to comply with criteria in current use to assess UV protection in spectacles for psoralen-sensitised patients. However, the improved UV-blocking characteristics of contact lenses identified in this paper compared to previous studies suggests that such a contact lens will soon become available. Meanwhile, contact lens-wearing systemically sensitised PUVA patients should continue to wear approved spectacles for eye protection whilst photosensitised with psoralen.

Contact Lenses↗
PubMed1999

Predictors of successful extubation in children.

Objective criteria to predict extubation outcome in mechanically ventilated children are not available. Our goal was to study factors associated with extubation success and to evaluate the usefulness of the rapid shallow breathing index (RSBI) and the compliance, resistance, oxygenation, and pressure index (CROP index) in children. Data were prospectively collected on 227 mechanically ventilated children. Patients successfully extubated had significantly better lung compliance (Cdyn: 0.59 +/- 0.91 versus 0.39 +/- 0.14 ml/kg/cm H(2)O), higher Pa(O(2))/FI(O(2)) ratio (382.4 +/- 181.2 versus 279.8 +/- 93.9), and lower Pa(CO(2)) (41.3 +/- 6.7 versus 47.3 +/- 8.5 mm Hg). Spontaneous breathing parameters showed significantly lower respiratory rates (RR) (36.6 +/- 17.9 versus 52.8 +/- 23 breaths/min), larger tidal volumes (VT) (7.3 +/- 2.6 versus 4.9 +/- 1.8 ml/kg), and greater muscle strength (negative inspiratory force [NIF]: 41.8 +/- 15.4 versus 35.1 +/- 12.5 cm H(2)O) in successfully extubated children. Extubation failures had higher RSBIs and lower CROP index values. A RSBI value of </= 8 breaths/ml/kg had a sensitivity of 74% and specificity of 74%, whereas a CROP value of >/= 0.15 ml/kg/breaths/min had a sensitivity of 83% and specificity of 53% for extubation success. Children failing extubation demonstrate abnormalities of respiratory function. The RSBI and CROP index are useful to predict pediatric extubation success.

Airway Resistance↗
PubMed1999

Talking trash: the economic and environmental issues of landfills.

The U.S. per-capita figure for garbage production has topped four pounds per person per day, and that amount is rising at roughly 5% per year. In the past, municipal solid waste was sent to the nearest local landfill or incinerator. But in 1988, the U.S. Environmental Protection Agency instituted the first federal standards for landfills, designed to make them safer. Over 10,000 small municipal landfills have since been consolidated into an estimated 3,500 newer, safer landfills, some of which are "megafills" that can handle up to 10,000 tons of waste a day. The new landfills are outfitted to prevent air and water pollution and limit the spread of disease by scavengers. Although the new landfills provide better controls against air and water pollution as well as an alternate source of municipal income, they are not entirely problem-free. Some experts believe the new landfill technology has not been properly tested and will therefore not provide protection in the long run. Others feel that poorer, less well-informed communities are targeted as sites for new landfills. In addition, many people that live near megafills, which may draw garbarge from several states, are unhappy about the noise, truck traffic, odors, and pests caused by the facilities.

Economics↗
PubMed1999

Long-term interferon-alpha 2A does not induce sustained hematologic remission in younger patients with essential thrombocythemia.

The ability of Interferon alpha (alpha-IFN) to alter the natural history of essential thrombocythemia (ET) and induce sustained hematologic remission would provide further impetus to consider this agent in younger patients with this disease and may influence the decision to commence treatment in asymptomatic patients. This study has failed to demonstrate any sustained hematologic remissions after cessation of long-term (2 years) alpha-IFN administration in a group of 34 female patients with a median age of 41 years (range 14-68) who were considered at intermediate to high risk of thrombotic complications. In the twenty-one patients completing two years of therapy, 13 (62%) had complete hematological responses (CHR; platelet count <400 x 10(9)/L), 7 (33%) partial hematological responses (PHR; platelet count 400-600 x 10(9)/L) and no thrombotic or hemorrhagic complications occurred. In all patients who discontinued alpha-IFN at 2 years, platelet counts rose above the normal range within 1-4 months and the majority required reinstitution of some form of therapy. The inability of long-term alpha-IFN to induce sustained, unmaintained hematologic remission argues strongly against any significant effect on the neoplastic clone at the doses used in this study. This study does, however, confirm the efficacy of long-term alpha-IFN in younger female patients with ET, a group not previously well represented in clinical trials of the agent.

Adolescent↗
PubMed1999

The effect of nefazodone on clozapine plasma concentrations.

The cytochrome enzyme p4503A4 (CYP3A4) is thought to play a major part in the human metabolism of clozapine. Nefazodone is a potent and specific in-vivo inhibitor of CYP3A4. We co-administered nefazodone and clozapine in six patients and found that mean clozapine levels rose by 4% of baseline and norclozapine levels by 16%. Based on these observations, it is inferred that inhibition of CYP3A4 in vivo has minimal effects on clozapine metabolism. Nefazodone appears to be safe when co-administered with clozapine.

Adult↗
PubMed1999

Application of mixed models to assess exposures monitored by construction workers during hot processes.

Particulate exposures were assessed among construction workers engaged in hot processes in four jobs (boilermakers, ironworkers, pipefitters and welder-fitters) at nine sites in the U.S. After being trained by occupational hygienists, the workers obtained shift-long personal samples at each site for total particulates (TP). Selected samples were also assayed for manganese (Mn), nickel (Ni), and chromium (Cr). Workers provided information about process- and task-related covariates that were present on the days of monitoring. Data were investigated with mixed-model regression analyses that designated the jobs and covariates as fixed effects and the worker and error terms as random effects. Results indicated that the within-worker variance components, but not the between-worker variance components, could be pooled among jobs. Mean air levels for a given agent varied by roughly six to 100 fold among the jobs, with boilermakers and ironworkers experiencing much higher levels of TP and Mn than pipefitters and welder-fitters. Limited data also suggested that welder-fitters were exposed to greater levels of Ni and Cr than pipefitters. Sufficient sample sizes were available to evaluate the effects of covariates upon exposures to TP and Mn. As expected, processes involving more than 50% hot work led to substantially higher levels of TP and Mn than those involving shorter durations of hot work. Local-exhaust or mechanical ventilation reduced exposure to TP (but not Mn) by as much as 44%, and shielded or manual arc welding increased exposure to Mn (but not TP) by about 80%. Parameters estimated with these mixed models were used to calculate probabilities that workers were exposed at levels above U.S. occupational exposure limits (OELs). Regarding TP and Mn, these calculations suggested that 26-95% of exposures to boilermakers and pipefitters and 2-13% of exposures to pipefitters and welder-fitters exceeded the current Threshold Limit Values. Among welder-fitters, limited data also pointed to probabilities of 2-50% for exceeding particular OELs for Ni and Cr. Using the significance of the estimated random-worker effects as a gauge for the uniformity of exposure within a job, administrative or engineering changes appear appropriate for reducing exposures to boilermakers and ironworkers, while individual personal environments should be investigated for pipefitters and welder-fitters.

Hot Temperature↗
PubMed1999

Implementing a nurse information system in a nurse-managed primary care practice: a process in progress.

As part of a larger project, a nurse-managed primary care clinic (Valencia Pediatric and Family Practice) sought to implement a nursing information system for the purposes of (1) patient record keeping, (2) capturing advanced practice nursing interventions and outcomes and transforming them into standardized language, (3) project data management, and (4) evaluating advanced practice nursing care thereby improving and standardizing quality of care. This article represents the background information for selection of a data management system and early experiences of implementation.

Database Management Systems↗
PubMed1999

Clinical Experience with Intermittent Androgen Suppression in Prostate Cancer: Minimum of 3 Years' Follow-Up.

This report reviews the long-term follow-up of a prospective Phase II evaluation of intermittent androgen suppression in the treatment of prostate cancer. A total of 87 patients have been entered in this protocol. At the time of this report, 50 men have been followed for a minimum of 3 years. Treatment was initiated with combined androgen blockade and continued for at least 6 months until a serum PSA nadir was observed. Medication was then withheld until the serum PSA increased to mean values between 10 and 20 ng/mL. This cycle of treatment and no treatment was repeated until the regulation of PSA became androgen independent. The total time in the study ranges from 40 to 126 months, with a mean of 65.5 months. The off-treatment period in the first cycle for the men with long-term follow-up was associated with an improvement in the sense of well-being and recovery of libido and potency in men who reported normal or near-normal sexual function before the start of therapy. The average time off therapy (percentage time off therapy) for cycles 1, 2, 3, and 4 was 15 months (54%), 10 months (48%), 8 months (45%), and 7 months (40%), respectively. The study group included 9 patients treated because of a rising PSA concentration after radiation therapy for locally advanced cancer. These patients have been off therapy for an average of 22 and 13 months in treatment cycles 1 and 2, respectively. Six patients with rising PSA values after radical prostatectomy and with follow-up exceeding 36 months have been off therapy for an average of 19 and 11 months in treatment cycles 1 and 2, respectively. Of the 87 patients, 23 have had their disease progress to androgen independence at a median of 32 months of treatment, and 13 have died cancer-specific deaths at a median of 48 months. Prostate cancer is amenable to control by intermittent androgen suppression. This approach affords an improved quality of life when the patient is off therapy, with reduced toxicity and costs. Phase II trials suggest that there is not a negative impact on patient outcome. Randomized protocols are currently in progress to determine whether survival is affected in a beneficial or adverse way by such treatment in men with locally recurrent or metastatic cancer.

Journal Article↗