Search PubMed⌕ Search

Biomedical subjects

R Miller

Publications and source records attributed to R Miller.

At least 55 records · Page 3Linked to original sources
PubMed1999

Incidence rates of first-ever ischemic stroke subtypes among blacks: a population-based study.

BACKGROUND AND PURPOSE: The aim of this study was to determine the incidence rates of ischemic stroke subtypes among blacks. METHODS: Hospitalized and autopsied cases of stroke and transient ischemic attack among the 187 000 blacks in the 5-county region of greater Cincinnati/northern Kentucky From January 1, 1993, through June 30, 1993, were identified. Incidence rates were age- and sex-adjusted to the 1990 US population. Subtype classification was performed after extensive review of all available imaging, laboratory data, clinical information, and past medical history. Case-control comparisons of risk factors were made with age-, race-, and sex-matched control subjects. RESULTS: Annual incidence rates per 100 000 for first-ever ischemic stroke subtypes among blacks were as follows: uncertain cause, 103 (95% confidence interval [CI], 80 to 126); cardioembolic, 56 (95% CI, 40 to 73); small-vessel infarct, 52 (95% CI, 36 to 68); large vessel, 17 (95% CI, 8 to 26); and other causes, 17 (95% CI, 9 to 26). Of the patients diagnosed with an infarct of uncertain cause, 31% underwent echocardiography, 45% underwent carotid ultrasound, and 48% had neither. Compared with age-, race-, and sex- (proportionally) matched control subjects from the greater Cincinnati/northern Kentucky region, the attributable risk of hypertension for all causes of first-ever ischemic stroke is 27% (95% CI, 7 to 43); for diabetes, 21% (95% CI, 11 to 29); and for coronary artery disease, 9% (95% CI, 2 to 16). For small-vessel ischemic stroke, the attributable risk of hypertension is 68% (95% CI, 31 to 85; odds ratio [OR], 5.0), and the attributable risk of diabetes is 30% (95% CI, 10 to 45; OR, 4.4). For cardioembolic stroke, the attributable risk of diabetes is 25% (95% CI, 4 to 41; OR, 3.1). CONCLUSIONS: Stroke of uncertain cause is the most common subtype of ischemic stroke among blacks. Cardioembolic stroke and small-vessel stroke are the most important, identifiable causes of first-ever ischemic stroke among blacks. The incidence rates of cardioembolic and large-vessel stroke are likely underestimated because noninvasive testing of the carotid arteries and echocardiography were not consistently obtained in stroke patients at the 18 regional hospitals. Most small-vessel strokes in blacks can be attributed to hypertension and diabetes.

Black or African American↗
PubMed1999

A regulatory perspective on pharmacokinetic/pharmacodynamic modelling.

We present an integrated summary from statistical and pharmacological perspectives of pharmacokinetic/pharmacodynamic (PK/PD) modelling and its use in drug development and regulation for guiding appropriate dosing. An overview of the technical aspects of PK/PD modelling describes how structural models are constructed and refined using pharmacokinetic and pharmacodynamic principles and how random effects models are used to account for individual differences in desired (and undesired) responses due to patient characteristics. Lastly, we describe applications of PK/PD modelling for the purposes of drug labelling, for resolving a safety concern, and for improving therapeutic monitoring of anaesthetic depth during surgery.

Biometry↗
PubMed1999

Treatment of multiple glomangioma with tuneable dye laser.

BACKGROUND: Multiple glomangiomas are a rare clinical occurrence. In the past, various treatments have been proposed for eradication of these tumours. OBJECTIVE: An alternative and effective therapy for multiple glomangioma is proposed. RESULTS: The effective clinical response of multiple, painful, bluish-black lesions on the soles of the feet and the hands, diagnosed as multiple glomangioma, to flashlamp tuneable dye laser is reported. CONCLUSION: The flashlamp tuneable dye laser is an effective modality in the treatment of multiple glomangioma.

Adult↗
PubMed1999

Screening methods for thyroid hormone disruptors.

The U.S. Congress has passed legislation requiring the EPA to implement screening tests for identifying endocrine-disrupting chemicals. A series of workshops was sponsored by the EPA, the Chemical Manufacturers Association, and the World Wildlife Fund; one workshop focused on screens for chemicals that alter thyroid hormone function and homeostasis. Participants at this meeting identified and examined methods to detect alterations in thyroid hormone synthesis, transport, and catabolism. In addition, some methods to detect chemicals that bind to the thyroid hormone receptors acting as either agonists or antagonists were also identified. Screening methods used in mammals as well as other vertebrate classes were examined. There was a general consensus that all known chemicals which interfere with thyroid hormone function and homeostasis act by either inhibiting synthesis, altering serum transport proteins, or by increasing catabolism of thyroid hormones. There are no direct data to support the assertion that certain environmental chemicals bind and activate the thyroid hormone receptors; further research is indicated. In light of this, screening methods should reflect known mechanisms of action. Most methods examined, albeit useful for mechanistic studies, were thought to be too specific and therefore would not be applicable for broad-based screening. Determination of serum thyroid hormone concentrations following chemical exposure in rodents was thought to be a reasonable initial screen. Concurrent histologic evaluation of the thyroid would strengthen this screen. Similar methods in teleosts may be useful as screens, but would require indicators of tissue production of thyroid hormones. The use of tadpole metamorphosis as a screen may also be useful; however, this method requires validation and standardization prior to use as a broad-based screen.

Animals↗
PubMed1999

A phase I single-dose trial of gadolinium texaphyrin (Gd-Tex), a tumor selective radiation sensitizer detectable by magnetic resonance imaging.

Gadolinium Texaphyrin (Gd-Tex) is a radiation sensitizer with a novel mechanism of action that sensitizes both oxic and hypoxic cells, localizes selectively in tumors, and is detectable by magnetic resonance imaging (MRI). This Phase I single-dose trial of Gd-Tex administered concurrently with radiation therapy was carried out to determine the maximally tolerated dose (MTD), dose-limiting toxicities, pharmacokinetics, and biolocalization of Gd-Tex as determined by MRI. Adults with incurable cancers of any histology requiring radiation therapy were eligible. A single i.v. dose of Gd-Tex was followed at least 2 h later by radiation therapy. The Gd-Tex dose was escalated in cohorts of 3 to 5 patients. Thirty-eight patients (median age, 58 years; range, 35-77 years) with incurable cancers of the lung (26), cervix (3), or other solid tumors (9) received a total of 41 single administrations of Gd-Tex. The Gd-Tex dose was escalated from 0.6 to 29.6 mg/kg. Irradiated sites included the thorax, brain, pelvis, bone, soft tissue, and sites of nodal metastases. The MTD was 22.3 mg/kg, determined by reversible acute tubular necrosis as the dose-limiting toxicities. Gd-Tex selectively accumulated in primary and metastatic tumors as demonstrated by MRI. No increase in radiation toxicity to normal tissues was seen. The median half-life of Gd-Tex after single-dose administration is 7.4 h. This study demonstrates that Gd-Tex is well tolerated in doses below the MTD, and that there is selective biolocalization in tumors. The maximum recommended dose for single administrations is 16.7 mg/kg.

Adult↗
PubMed1999

Re-analysis of 2,4-D use and the occurrence of canine malignant lymphoma.

An independent scientific review panel had concerns involving study design, analysis and interpretation of results in a case-control study investigating the relationship between canine malignant lymphoma (CML) and the use of 2,4-D herbicide. To address these concerns, a re-analysis was done to examine 2,4-D use and its association with CML. This case-control study re-analyzed the data using the exposure definition used in the original study, re-analyzed the data using a redefinition of exposure, and conducted a dose-response analysis with the redefined exposure criteria. Our results agreed with the original author's analyses that no effects were found when stratifying by survey method and geographic region, and that there were no significant differences between separated and pooled control groups. However, we did not confirm a dose-response relationship between 2,4-D use and CML. Additionally, the occurrence of CML was not found significantly associated with the use of 2,4-D.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1999

Effects of the Medicare Alzheimer's Disease Demonstration on nursing home entry.

STUDY QUESTION: Did the Medicare Alzheimer's Disease Demonstration, with its goal of improving caregiver outcomes through case management and subsidized community services, affect the nursing home entry rate of treatments with dementia compared to controls? DATA SOURCES: Interviews conducted at baseline and six months thereafter. Measures include date of nursing home entry, client and caregiver health, and income. STUDY DESIGN: The demonstration randomly assigned voluntary applicants into treatment and control groups. Treatment group cases were eligible for case management and for an 80 percent discount on community care benefits, up to about $600 per month. DATA COLLECTION: All cases received baseline and semi-annual assessment interviews for up to three years after enrollment. Analyses are among cases that remained in the demonstration for more than 30 days after enrollment (n = 8,095). PRINCIPAL FINDINGS: The intervention of case management and subsidized community service had no effect on nursing home entry rates for treatments overall, compared to those of controls, and few effects on treatment subgroups, with the exception of one site where it may have increased nursing home entry rates. CONCLUSIONS: Providing case management and subsidized community services with the goal of improving caregiver outcomes may have little effect on nursing home entry rates for people with dementia.

Adult↗
PubMed1999

Comparison of the Bayesian approach and a limited sampling model for the estimation of AUC and Cmax: a computer simulation analysis.

OBJECTIVES: To compare two limited sampling methods (Bayesian and the limited sampling model) for the estimation of AUC and Cmax following a single oral dose of a hypothetical drug. METHODS: The plasma concentration vs time data sets for 50 subjects using a linear one- or two-compartment pharmacokinetic model were generated by simulation. The limited sampling model (LSM) was developed using samples from 10 subjects using one or two time points. The simulated plasma concentrations were also used for Bayesian evaluation. Bayesian analysis was performed on Non-Mem and mean pharmacokinetic parameters used for simulation were assumed as population pharmacokinetic parameters. In addition a test drug was also used to compare the predicted AUC and Cmax for the two approaches. RESULTS: Both methods were validated in 40 subjects for the hypothetical drug and in 12 subjects for the test drug. Both methods provided good estimates of AUC and Cmax. CONCLUSION: The results indicate that the LSM is similar to the Bayesian method and may be used in lieu of the Bayesian approach in estimating AUC and Cmax using one or two samples in clinical settings without detailed pharmacokinetic studies.

Area Under Curve↗
PubMed1999

Presentation of ALS to the otolaryngologist/head and neck surgeon: getting to the neurologist.

Patients with early symptoms of bulbar amyotrophic lateral sclerosis (ALS) are usually referred to the otolaryngologist without a diagnosis. Careful examination of the speech quality and a physical exam, including the vocal cords, should be undertaken. The emotional state of the patient should be considered, and a diagnosis should not be offered before a neurologic consultation has been obtained. Patients with late symptoms of bulbar ALS almost always present with both significant speech and swallowing abnormalities. Evaluation can be difficult because many abnormalities are found on examination. Advanced progression of symptoms is a clear indication for rapid referral to a neurologist if a diagnosis has not already been made. Supportive and symptomatic care should be offered to the patient immediately. The University of Washington Neuromuscular Clinic for Speech and Swallowing Disorders has seen 600 new neurologic patients since 1986, 211 of whom were ALS patients. The introduction of percutaneous gastrostomy has greatly changed the management of ALS patients, and 75 patients have undergone this procedure (32% because of inadequate swallowing, 68% for declining vital capacity). Medical management to improve symptoms may be indicated before surgery. Surgical options for patients with late salivary presentation are uncommon and include removal of the submaxillary glands, tracheostomy, and laryngeal or salivary diversion procedures. Laryngectomy or laryngeal diversion procedures are only very rarely indicated. Although tracheostomy usually interferes with swallowing and worsens aspiration, it may rarely be indicated in patients with late airway presentation for glottic narrowing or artificial respiratory support. Symptomatic management of patients with bulbar ALS is usually best undertaken by a multidisciplinary clinic that can provide a physically and psychologically supportive environment.

Aged↗
PubMed1999

A programmable rules engine to provide clinical decision support using HTML forms.

The authors have developed a simple method for specifying rules to be applied to information on HTML forms. This approach allows clinical experts, who lack the programming expertise needed to write CGI scripts, to construct and maintain domain-specific knowledge and ordering capabilities within WizOrder, the order-entry and decision support system used at Vanderbilt Hospital. The clinical knowledge base maintainers use HTML editors to create forms and spreadsheet programs for rule entry. A test environment has been developed which uses Netscape to display forms; the production environment displays forms using an embedded browser.

Artificial Intelligence↗
PubMed1999

Phase-specific psychosocial interventions for first-episode schizophrenia.

Phase-specific psychosocial interventions for first-episode schizophrenia are outlined and described using examples from clinical practice with 68 patients. These interventions are based on the unique aspects of the first episode and patients' clinical states. Although schizophrenia may run an uneven and often unpredictable course, most patients experience three distinct phases: (1) the acute phase, (2) the healing phase, and (3) the maintenance phase. The timeliness of phase-specific interventions is crucial in helping both patients and families understand the illness, evaluate options, accept treatment, and adjust to changes in functioning and expectations.

Acute Disease↗
PubMed1999

A phase II trial of docetaxel (Taxotere) in hormone-refractory prostate cancer: correlation of antitumor effect to phosphorylation of Bcl-2.

Twenty-one patients with hormone refractory prostate cancer were enrolled to receive single-agent docetaxel (Taxotere; Rhône-Poulenc Rorer, Collegeville, PA) 75 mg/m2 intravenously every 21 days. Six patients consented to biopsies of the prostate tumor before and following the first cycle of chemotherapy and 11 patients underwent periodic blood collection for isolation of the mononuclear cell fraction. The toxicities of treatment were moderate but included eight episodes of grade III and two episodes of grade IV nonhematologic toxicity as well as seven episodes of grade III and 11 episodes of grade IV hematologic toxicity (primarily neutropenia, including four episodes of febrile neutropenia). An objective response of more than 50% reduction in prostate-specific antigen was observed in seven patients (38%) and more than half of the patients with symptomatic disease at the initiation of therapy had improvements on treatment. Radiographic or scintigraphic evidence of tumor regression was observed in six patients. Nine patients experienced a prolonged period of stable disease on treatment (median, six cycles). Tumor specimens are currently being analyzed for bcl-2 expression and phosphorylation. The current series confirms the substantial single-agent activity of docetaxel in hormone refractory prostate cancer and may help to further elucidate its mechanism of action at the molecular level.

Aged↗
PubMed1999

Stop the carts.

Nurses and pharmacists at the University of Utah Hospitals & Clinics successfully implement an automated medication distribution system to cut costs, and find they also create measurable process improvements.

Clinical Pharmacy Information Systems↗
PubMed1998

Surface Behavior of Spread Sodium Eicosanyl Sulfate Monolayers.

The surface behavior of spread sodium eicosanyl sulfate monolayers is characterized by determining the dilational moduli from different pi/A isotherms and from surface stress relaxation experiments in the short-time range (<10 min). The elasticities derived from the pi/A isotherms differ depending on the experimental conditions. The quasi-equilibrium isotherm displays a plateau in the range of coexistence of the condensed and the expanded phases and strong increases caused by the formation of a solid-like phase. In contrast, nonequilibrium pi/A isotherms yield effective elasticities showing a maximum within the phase coexistence range. The formation of a solid phase cannot be detected because of the onset of monolayer collapse. Different stress relaxation experiments were carried out for monolayer compression and dilation using transient drop volume jumps. Depending on the experimental run, these experiments lead to consistent and complementary results with those derived from pi/A isotherms under comparable conditions. The stress recoveries yield a relaxation time, a dilation viscosity, and a parameter characterizing the homogeneity of the relaxation process. The stress relaxation is interpreted accounting for both the nonequilibrium between the monolayer and the bulk phase and the nonequilibrium within the monolayer. The influence of alkylsulfate hydrolysis on the presented results was checked. It was found that within the time scale of the experiments no influence of hydrolysis could be detected. Copyright 1998 Academic Press.

Journal Article↗
PubMed1998

The 1.1 A resolution crystal structure of [Tyr15]EpI, a novel alpha-conotoxin from Conus episcopatus, solved by direct methods.

Conotoxins are valuable probes of receptors and ion channels because of their small size and highly selective activity. alpha-Conotoxin EpI, a 16-residue peptide from the mollusk-hunting Conus episcopatus, has the amino acid sequence GCCSDPRCNMNNPDY(SO3H)C-NH2 and appears to be an extremely potent and selective inhibitor of the alpha3beta2 and alpha3beta4 neuronal subtypes of the nicotinic acetylcholine receptor (nAChR). The desulfated form of EpI ([Tyr15]EpI) has a potency and selectivity for the nAChR receptor similar to those of EpI. Here we describe the crystal structure of [Tyr15]EpI solved at a resolution of 1.1 A using SnB. The asymmetric unit has a total of 284 non-hydrogen atoms, making this one of the largest structures solved de novo by direct methods. The [Tyr15]EpI structure brings to six the number of alpha-conotoxin structures that have been determined to date. Four of these, [Tyr15]EpI, PnIA, PnIB, and MII, have an alpha4/7 cysteine framework and are selective for the neuronal subtype of the nAChR. The structure of [Tyr15]EpI has the same backbone fold as the other alpha4/7-conotoxin structures, supporting the notion that this conotoxin cysteine framework and spacing give rise to a conserved fold. The surface charge distribution of [Tyr15]EpI is similar to that of PnIA and PnIB but is likely to be different from that of MII, suggesting that [Tyr15]EpI and MII may have different binding modes for the same receptor subtype.

Amino Acid Sequence↗
PubMed1998

The Shake-and-Bake structure determination of triclinic lysozyme.

The crystal structure of triclinic lysozyme, comprised of 1,001 non-H protein atoms and approximately 200 bound water molecules, has been determined ab initio (using native data alone) by the "Shake-and-Bake" method by using the computer program SnB. This is the largest structure determined so far by the SnB program. Initial experiments, using default SnB parameters derived from studies of smaller molecules, were unsuccessful. In fact, such experiments produced electron density maps dominated by a single large peak. This problem was overcome by considering the choice of protocol used during the parameter-shift phase refinement. When each phase was subjected to a single shift of +/-157.5 degrees during each SnB cycle, an unusually high percentage of random trials (approximately 22%) yielded correct solutions within 750 cycles. This success rate is higher than that typically observed, even for much smaller structures.

Crystallography, X-Ray↗