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Biomedical subjects

M Anderson

Publications and source records attributed to M Anderson.

At least 541 records · Page 30Linked to original sources
PubMedDate not supplied

Sulbactam/ampicillin: in vitro spectrum, potency, and activity in models of acute infection.

More than 90% of community hospital-isolated strains of Staphylococcus (including methicillin-resistant isolates), Streptococcus, Haemophilus, Neisseria, Branhamella, Bacteroides, Escherichia coli, Klebsiella, Enterobacter aerogenes, Proteus, and Acinetobacter calcoaceticus were inhibited by the sulbactam/ampicillin (1:2) combination at concentrations of 8 micrograms/16 micrograms per ml. The peak serum level from a 15-min infusion of 1 g/2 g of sulbactam/ampicillin is more than seven times this 90% end point. Excellent bactericidal activity was demonstrated against ampicillin-resistant isolates. Ampicillin-resistant strains did not develop resistance to sulbactam/ampicillin when they were serially transferred in the presence of sublethal concentrations of the combination. In mice the combination was active against a variety of acute, fatal infections produced by ampicillin-resistant bacterial isolates, including methicillin-resistant strains of Staphylococcus aureus and mixed anaerobes. The in vitro and in vivo properties of sulbactam/ampicillin, coupled with its reliable pharmacokinetic performance, appear to make the combination ideally suited for the treatment of polymicrobial (aerobe-anaerobe) infections.

Acute Disease↗
PubMedDate not supplied

Prazosin first-pass metabolism and hepatic extraction in the dog.

The short half-life, low plasma concentrations, and extensive biotransformation of prazosin suggest that it might be subject to extensive first-pass metabolism. Bioavailability, disposition, and hepatic extraction were studied in the dog. In conscious dogs whole blood prazosin concentrations were measured after oral and intravenous administration of the drug. Anesthetized dogs were used to measure prazosin concentrations in arterial and hepatic venous blood samples drawn simultaneously. The bioavailability of prazosin was 0.38 +/- 0.11. In anesthetized dogs the hepatic extraction of prazosin was 0.47 +/- 0.08 for a predicted availability of 0.53 +/- 0.08. Pharmacokinetic parameters were similar in conscious and anesthetized animals. Following intravenous administration to conscious dogs, prazosin concentrations in whole blood declined with a fast half-life of 3.9 +/- 1.74 min and a slow half-life of 153 +/- 24 min, the volume of distribution at steady state being 48.6 +/- 15.3 liters in dogs (mean weight, 22.6 kg). We conclude that prazosin availability following oral administration is low and that first-pass hepatic metabolism is largely responsible for this. A one-compartment model adequately describes prazosin pharmacokinetics in the dog.

Animals↗
PubMedDate not supplied

Detection of approximal caries in 5-year-old Swedish children.

The aim was to assess how accurately some commonly used risk factors/risk markers (predictors) for caries development could identify children with and without approximal caries as judged from bitewing radiography. Two hundred and sixty-seven consecutive 5-year-old children from two Swedish cities participated. Three experienced dentists examined the children. The predictors were the overall dmfs (decayed, missing and filled surfaces) value (canines and molars), the number of occlusal dmfs, the frequency of intake of between-meal sugary products, visible plaque on free smooth surfaces of second primary molars, toothbrushing habits and (before bitewing examination) an overall judgement by the examining dentist. The mean dmfs value without bitewing examination was 0.40 (SD = 1.22). Twelve percent of the children had at least one dentin lesion and 33% at least one enamel lesion that were detected from bitewing examination only. The gain from adding bitewing examination to clinical examination amounted to a mean of 1.2 approximal enamel and/or dentin lesions. The ability to correctly identify children with approximal caries from the predictors was limited; sensitivity ranged from 0.27 to 0.75 and specificity ranged from 0.41 to 0.93. The single best predictor was the dentist's overall judgement with an average precision of 73%; average sensitivity for the presence of enamel and dentin lesions was 0.48 and for the presence of dentin lesions 0.66. The rest of the predictors added little to the predictive power. It is concluded that 33% of the 5-year-olds, representing a low caries prevalence population, benefited from bitewing examination. The ability to identify these children from the predictors was, however, limited.

Child, Preschool↗
PubMedDate not supplied

Concurrent fluorescence in situ hybridization and immunocytochemistry for the detection of chromosome aberrations in exfoliated bronchial epithelial cells.

OBJECTIVE: A procedure was developed to allow concurrent detection of chromosome aberrations and identification of bronchial epithelial cells. STUDY DESIGN: Fluorescence in situ hybridization for chromosome 7 and immunocytochemistry for cytokeratin were performed on exfoliated bronchial epithelial cells in a sputum sample from a cancer patient. RESULTS: The Spectrum Orange-labeled alpha satellite probe for chromosome 7 produced red fluorescence, nuclei were counterstained with 4,6-diamidino-2-phenylindole (blue), and cytokeratin was visualized using a fluorescein isothiocyanate (FITC)-conjugated secondary antibody (green). CONCLUSION: This procedure allowed the rapid identification of airway epithelial cells with numerical chromosome aberrations in this sample. Ultimately, this procedure could increase the sensitivity and specificity of sputum cytology as a laboratory diagnostic tool for the early detection of lung cancer.

Antibodies, Monoclonal↗
PubMedDate not supplied

Saccomanno smear slides and Megafunnel slides for sputum specimens. A comparison.

OBJECTIVE: To compare Megafunnel slides to standard Saccomanno smear slides of sputum specimens and evaluate the use of Megafunnel slides for retrospective studies. STUDY DESIGN: Papanicolaou-stained Saccomanno smear and Megafunnel slides (Shandon Lipshaw, Inc., Shandon Inc., Pittsburgh, Pennsylvania, U.S.A.) of 65 clinical sputum specimens from 51 patients were compared for cellular morphology, staining, background and cytologic diagnosis. Recovery of diagnostic cells was quantitated using 10 of these specimens. Megafunnel slides prepared from the clinical sputum samples were immunocytochemically stained. Diagnostic cells were quantitated both before removal from 64 archived Saccomanno smear slides and after placement of these cells onto 238 Megafunnel slides. RESULTS: Saccomanno smear slides and Megafunnel slides of clinical specimens were similar in morphology, background, staining, diagnosis and cell recovery. Megafunnel slides were superior for multiple immunocytochemical stains. The production of multiple Megafunnel slides from archival smear slides provided a method of performing numerous retrospective studies. CONCLUSION: Megafunnel slides compared favorably to Saccomanno smear slides in the quality of specimens but are more expensive and labor intensive to prepare. However, the reduction in screening time by cytotechnologists may be advantageous. Additionally, their potential use for immunocytochemistry, fluorescence in situ hybridization, or other special clinical and research analyses is very promising.

Antibodies↗
PubMedDate not supplied

Middle cerebral artery occlusion with migraine.

A seven-year-old boy with migraine and a family history of hemiplegic migraine is described who, during an exacerbation, developed dysphasia and right hemiparesis. A CT scan showed a hypodense left cerebral lesion. Angiography revealed occlusion of the left middle cerebral artery at its origin. This represents the youngest case of stroke with migraine and, to our knowledge, is the first case report of angiogram-documented middle cerebral occlusion associated with migraine.

Cerebral Angiography↗
PubMedDate not supplied

Vascular access in cystic fibrosis--does size matter?

UNLABELLED: Vascular access is an important part of patient management in cystic fibrosis. In most instances, vascular access is straightforward. However, a single bad experience with venepuncture has a lasting impact. Clinical experience suggested that for some individuals a smaller, shorter intravenous catheter (Leaderflex 22G, 0.7 mm 8.0 cm, Vygon) might be a suitable alternative to standard vascular access via a standard long-line (2 Fr or 3 Fr Nutriline, Vygon). METHODS: Between September 2002 and May 2004 we offered a free, fully informed choice between a standard 30 cm long line or a shorter (8 cm) Leaderflex line and audited this change in practice. RESULTS: A total of 56 lines were inserted over the study period. Data were available for 54 of these (22 Leaderflex and 32 standard long lines). Mean and median line survival was omparable. Leaderflex lines survived for a mean of 12.2 days and median of 14 days. Standard long lines survived for a mean of 12.6 days and median of 14 days. DISCUSSION: Leaderflex lines offer a well-tolerated alternative to standard long lines for the administration of a 14-day course of intravenous antibiotics. Their reduced size and cost offer advantages to patients and doctors.

Journal Article↗
PubMedDate not supplied

Cardiovascular safety of second-generation antihistamines.

Reports of serious cardiac arrhythmia associated with some second-generation antihistamines have prompted concern for their prescription. This article reviews the nature of the adverse events reported and concludes that the blockade of potassium channels, particularly the subtype responsible for the rapid component of the delayed rectifier current (IKr), is largely responsible for such adverse cardiac events. Consequently, antihistamines with little or no interaction with these channels are expected to have the greatest safety margin. The main cardiac arrhythmia of concern is that of torsades de pointes, a potentially fatal phenomenon characterized by prolonged ventricular depolarization that manifests as a prolonged QT interval and polymorphic ventricular tachycardia, with twisting of the QRS complexes. Based on pre-clinical and clinical evidence, it appears that loratadine, cetirizine, and fexofenadine are safe from cardiac arrhythmia via the IKr channel, whereas astemizole and terfenadine have a propensity to cause ventricular tachyarrhythmias.

Animals↗
PubMedDate not supplied

Human tracheobronchial deposition and effect of two cholinergic aerosols.

The effects of two methacholine aerosols with mass median diameters congruent to 7 and 3 microns were measured in 10 healthy subjects. The concentrations of the two aerosols were increased until forced expiratory volume in 1 s (FEV1) decreased with about 20%. Pulmonary fraction (FEV1, FVC, FEV25-75%, FEF75-85%, R(aw), and phase III of single breath O2 test) and deposition of 3.6-microns radiolabeled Teflon particles were studied before and after bronchial challenge with the two aerosols. Output from the nebulizers and size distribution were measured and from these data and from data on deposition of Teflon particles from this and seven earlier studies the doses of the two methacholine aerosols to the tracheobronchial region were calculated. The changes in all pulmonary function parameters and deposition of 3.6-microns particles were similar for the two aerosols. The calculated dose for the aerosol with the large particles was 3-4 times higher than that with the smaller particles. The results indicate greater effect of a certain dose to the tracheobronchial part of the lung if the mass is spread on many small particles than on fewer large ones.

Adult↗
PubMedDate not supplied

Human deposition and clearance of 6-micron particles inhaled with an extremely low flow rate.

In human experimental data, tracheobronchial deposition reaches its maximum for particles of about 6 microns inhaled at 0.5 L/s. The purpose of the present study was to investigate if tracheobronchial deposition of 6-microns particles could be increased, especially in the smaller bronchi, using an extremely slow inhalation rate. Six healthy nonsmokers inhaled monodisperse 6-microns (aerodynamic diameter) Teflon particles labeled with 111In at 0.04 L/s. Radioactivity in mouth and throat, lung, and stomach was measured immediately after inhalation by profile scanning and in the lung also after 24, 48, 72, and 96 h. There was a substantial clearance between 24 and 72 h; around 20% of the total clearance occurred between 24 and 72 h. This is in contrast to earlier studies in which only around 1% of 6-microns particles inhaled at 0.5 L/s cleared between 24 and 72 h. This indicates a markedly higher deposition in the smaller bronchi at 0.04 L/s than at 0.5 L/s. The total tracheobronchial deposition was 50%, compared to about 30% when particles were inhaled at 0.5 L/s. These findings could be therapeutic use. They also implicate the possibility of developing a diagnostic model that can separate between bronchial reactivity in large and small bronchi.

Adult↗
PubMedDate not supplied

Retention of particles inhaled in boli with and without induced bronchoconstriction.

Large lung retentions (up to 50%) of particles < or = 4 microns inhaled with a bolus technique at a penetration depth less than dead space have been reported to occur after 24 h. This retention may be due to retarded clearance of particles deposited in the airways of the tracheobronchial tract; an alternative explanation could be that particles are deposited in the alveolar region. The purpose of the present study was to confirm the occurrence of retained fractions and to study the influence of a cholinergic drug, which is assumed to give a more central particle deposition, on these retentions in human lungs after shallow aerosol bolus inhalation. Twelve healthy subjects inhaled, with a bolus technique, monodisperse Teflon particles (2.4 microns geometric diameter, 3.5 microns aerodynamic diameter), labeled with 111In. The volumetric lung depth of the inspired bolus was around 60 mL and flow rate was about 300 mL/s. Six subjects inhaled the test particles after a provocation with a cholinergic aerosol, which induced a threefold increase in airway resistance. The other six subjects inhaled a cholinergic aerosol after inhalation of the test particles or inhaled no cholinergic aerosol at all. Radioactivity in the body was measured after 0.5, 24, 48, and 72 h with a whole-body scanner with three 127 x 101-mm Nal detectors. The investigation confirmed results obtained earlier by a group in Frankfurt claiming that great retentions occur after 24 h. The retentions tended to be lower in the group receiving a bronchoconstricting drug before the bolus inhalations. There was a significant lung clearance of particles between 24 and 72 h, in contrast to the findings in earlier studies in healthy subjects and asthmatics who inhaled Teflon particles in large volumes. On the other hand, the clearance agreed well with the clearance in healthy subjects with extensive deposition of Teflon particles in the small ciliated airways, obtained by means of an extremely low inhalation flow rate. The results suggest that a considerable fraction of the particles in the bolus inhalation have been deposited in small ciliated airways in which the mucociliary transport is less efficient or in the alveolar region.

Administration, Inhalation↗
PubMedDate not supplied

Human bronchiolar deposition and retention of 6-, 8- and 10-micrograms particles.

Three groups, each consisting of 6 healthy subjects, inhaled, respectively, 6-micrograms (aerodynamic diameter), 8-micrograms, and 10-micrograms Teflon particles, labeled with indium-111. The particles were inhaled at an extremely low flow rate, 0.05 L/s. Lung retention was measured after 0, 24, 48, and 72 h. Two models were used to calculate particle deposition in the lungs in the various generations: the Karolinska Institute model (KI model) and the University of Southampton model (US model). From the experimental clearance data and the theoretical deposition data, it was calculated that the average retention after 24 h was around 100% for particles deposited in generations 13-16 (ciliated bronchioles) and around 20% in generations 0-12 (both large and small ciliated airways). In these calculations, it was assumed that the retained fractions were independent of particle size. The depositions in the bronchial region (generations 0-8), bronchiolar region (generations 9-15 or 9-16), and the alveolar region were calculated using the two models and compared with the recent ICRP model. On the whole, the three models agreed fairly well.

Administration, Inhalation↗
PubMedDate not supplied

Hypertropia following trochlear trauma.

Hypertropia following trauma to the trochlea is rare. The more widely recognized response of the trochlea to trauma is hypotropia or acquired Brown syndrome. We observed three cases of hypertropia following penetrating trauma to the trochlea. Each had computerized tomography and/or magnetic resonance imaging to assist in the understanding of the mechanism of the observed superior oblique dysfunction. The clinical course of these cases was variable. Awareness of the damaged trochlea's capacity to respond as a hypertropic as well as a hypotropic syndrome will allow for improved management of these unusual patients.

Adolescent↗
PubMedDate not supplied

Storytelling as a teaching-learning tool with RN students.

The Registered Nurse student returning to school brings both a knowledge base and experiences that lend themselves to enriching the learning environment. These experiences have helped to develop the practical knowledge and expertise that is evident in their practice. When these experiences are shared in the form of stories, they provide a mechanism for transformation within the learner. This study focused on the use of storytelling in teaching and empowering RN students to become involved in their own learning and fostering critical reflection. The RN students in this study represented a diverse ethnic/racial group. As a result, students were challenged to understand and manage cultural diversity and value cultural differences. The use of storytelling engaged students in reflective thinking, writing, and learning activities that identified assumptions, alternative ways of thinking, teaching, and practicing nursing.

Cultural Diversity↗