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Biomedical subjects

K Miller

Publications and source records attributed to K Miller.

At least 721 records · Page 40Linked to original sources
PubMedDate not supplied

Adjuvant properties of polysaccharides: effect of iota-carrageenan, pectic acid, pectin, dextran and dextran sulphate on the humoral immune response in the rat.

Iota-carrageenan can both enhance agglutinating antibody responses and trigger reaginic antibody production against a protein associated antigen in rats. The present study investigates the strain specificity of this phenomenon and compares the adjuvanticity of high and low molecular weight iota-carrageenan with a series of structurally distinct polysaccharides (pectin, pectic acid, dextran and dextran sulphate). Using ovalbumin as the test antigen, high molecular weight iota-carrageenan induced a potent ovalbumin specific reaginic antibody response in PVG and Hooded Lister strain rats, an intermediate response in Sprague Dawley rats and a weak response in DA, AO and F344 strain rats. Further studies in PVG rats revealed that the nature and magnitude of the antibody response induced was influenced by the type of polysaccharide carrier used. Thus, whereas, high molecular weight carrageenan enhanced the agglutinating antibody (agglutinin) response and simultaneously elicited de novo reaginic antibody production to co-administered ovalbumin, low molecular weight carrageenan facilitated reaginic antibody production but had no effect on the agglutinin response. Pectin and dextran had no effect on the agglutinin response and failed to elicit reaginic antibody production. Conversely, pectic acid and dextran sulphate enhanced the agglutinin response and elicited a transient reaginic anti-ovalbumin response.

Adjuvants, Immunologic↗
PubMedDate not supplied

Intestinal uptake and immunological effects of carrageenan--current concepts.

Carrageenans are a group of high molecular weight sulphated polygalactans which find extensive use in the food industry as thickening, gelling and protein-suspending agents. Although there is no evidence to suggest that the persorption of small amounts of carrageenans across the intestinal barrier poses an acute toxic hazard, they are known to be biologically active in a number of physiological systems and extended oral administration in laboratory animals has been shown to modify both in vivo and in vitro immune competence. Whereas this effect could be attributed to carrageenan having a selective toxic effect on antigen-processing macrophages, additional studies suggest that macrophages can also influence immune responses by the timed release of immunoregulatory mediators. Evidence in support of this comes from in vitro studies which demonstrate that carrageenan-treated macrophages can, depending on conditions and time of administration, release either stimulatory or inhibitory factors. The former is known to be the immunostimulatory agent interleukin 1 (IL-1). The inhibitory factor, which is produced at an early stage following exposure to non-toxic doses of carrageenans, has yet to be formally identified but it is believed to be a prostaglandin because of its specific mode of action and short biological half-life. At present it is impossible to relate these studies to the human situation. Although it is established that carrageenans can cross the intestinal barrier of experimental animals, there is no evidence to suggest that the limited uptake that may occur in man in any way interferes with normal immune competence. Nevertheless, increased exposure may occur in the neonate during weaning, and adults and children following allergic reactions and episodes of gastrointestinal disease. Further studies under such conditions now seem warranted in order to elucidate the possible immunological consequences which may be associated with enhanced uptake of carrageenans in vulnerable groups.

Animals↗
PubMedDate not supplied

Appropriateness of intravenous cannulation by paramedics: a London study.

INTRODUCTION: The number of patients undergoing intravenous (IV) cannulation by paramedics has increased dramatically over recent years in the UK. Treatment protocols for cannulation in the field are loosely defined. Variation in practice may lead to patients' receiving differential treatment according to customary practice, rather than according to their clinical conditions. OBJECTIVES: To explore variations in practice and assess level of appropriatenesss of IV cannulation by London Ambulance Service (LAS) paramedics; to revise treatment protocols and work toward clinical guidelines, if indicated by study findings. METHODS: Skill usage data were analyzed for all LAS paramedics for 1995-96. All patients who were IV-cannulated and transported to three hospitals by LAS during March 1996 were identified. A panel of accident and emergency (A&E) and prehospital specialists judged each case for appropriateness. RESULTS: Variation during the year was wide, with a range of 1 to 221 (mean 47) patients cannulated per paramedic, although the majority showed some consistency in frequency of skill usage. A sample of 183 cases was reviewed. The majority judged 149 (81.4%) to be appropriate, although there was considerable disagreement between reviewers (kappa = 0.43, p < 0.001). Data suggested that those paramedics who cannulate more frequently cannulated less appropriately during the study period (lowest 30%: 73.9% appropriate; highest 30%: 45.8% appropriate, p = 0.05). CONCLUSION: Despite wide variation between paramedics, the panel judged overall appropriateness of cannulation to be high. The audit advisory group judged that new clinical guidelines might not achieve an improvement in practice and were not supported by study findings. It was recommended that variations be addressed through individual practice review.

Catheterization↗
PubMedDate not supplied

Quantifying uncertainty: calculating interval estimates using quality control results.

EPA's Great Lakes National Program Office (GLNPO) is leading one of the most extensive studies of a lake ecosystem ever undertaken. The Lake Michigan Mass Balance Study (LMMB Study) is a coordinated effort among state, federal, and academic scientists to monitor tributary and atmospheric pollutant loads, develop source inventories of toxic substances, and evaluate the fate and effects of these pollutants in Lake Michigan. A key objective of the LMMB Study is to construct a mass balance model for several important contaminants in the environment: PCBs, atrazine, mercury, and trans-nonachlor. The mathematical mass balance models will provide a state-of-the-art tool for evaluating management scenarios and options for control of toxics in Lake Michigan. At the outset of the LMMB Study, managers recognized that the data gathered and the model developed from the study would be used extensively by data users responsible for making environmental, economic, and policy decisions. Environmental measurements are never true values and always contain some level of uncertainty. Decision makers, therefore, must recognize and be sufficiently comfortable with the uncertainty associated with data on which their decisions are based. The quality of data gathered in the LMMB was defined, controlled, and assessed through a variety of quality assurance (QA) activities, including QA program planning, development of QA project plans, implementation of a QA workgroup, training, data verification, and implementation of a standardized data reporting format. As part of this QA program, GLNPO has been developing quantitative assessments that define data quality at the data set level. GLNPO also is developing approaches to derive estimated concentration ranges (interval estimates) for specific field sample results (single study results) based on uncertainty. The interval estimates must be used with consideration to their derivation and the types of variability that are and are not included in the interval.

Confidence Intervals↗
PubMedDate not supplied

Fetal metachromatic leukodystrophy: pathology, biochemistry and a study of in vitro enzyme replacement in CNS tissue.

Brain tissue from a fetus with the diagnosis of metachromatic leukodystrophy (MLD) became available at autopsy. Pathologic studies of the CNS showed inclusion bodies within oligodendroglia. The morphology of myelin was normal. Cells and myelin were isolated from the cerebrum; there was an increased level of sulfatide present in both fractions. In vitro studies of enzyme replacement in cultured MLD brain cells indicated that it may be possible to correct the abnormal sulfatide accumulation.

Brain↗
PubMedDate not supplied

Symbion acute ventricular assist device: nursing challenge.

A cardiac patient is rapidly deteriorating and facing imminent death. The medical team decides to insert an experimental ventricular assist device (VAD) to perform the work of the dying heart. How can the critical care nurse best care for a patient with this challenging and unyielding diagnosis?

Assisted Circulation↗
PubMedDate not supplied

Tape recorders: a therapeutic tool in long-term care.

Chronically ill adults were able to alter their behavioral patterns through the use of a tape recorder, which allowed them to gain control of their lives despite their disabilities.

Activities of Daily Living↗
PubMedDate not supplied

A study of the interaction between dirithromycin and astemizole in healthy adults.

The effect of a standard regimen of dirithromycin, a macrolide antibiotic, on the single-dose pharmacokinetics of the H (1) receptor blocker astemizole was evaluated in a sample of 18 healthy young adults (nine males and nine females). The study was conducted in a two-way cross-over fashion after the subjects had been randomly given either dirithromycin (two 250 mg tablets) or placebo (two tablets) every morning for 10 days. On the morning of the fourth dose of either dirithromycin or placebo each subject ingested a single 30-mg oral dose (three 10-mg tablets) of astemizole. The disposition kinetics of both astemizole and its major metabolite, N-desmethylastemizole, were characterized after measuring the concentrations of both analytes in the serum fraction of serial blood samples collected for 14 days after the astemizole dose. In addition, corrected QT (QT(c) ) intervals were estimated from electrocardiogram rhythm strips that were run 24 hours prior to the astemizole dose, 12 hours after the astemizole dose, and after the last treatment (dirithromycin or placebo) dose in both study periods. Pharmacokinetic parameters that were measured for both astemizole and N-desmethylastemizole during each treatment were: C(max), t(max), AUC (0-infinity), CL(oral), half-life, and volume of distribution (V). None of the parameters for N-desmethylastemizole was different when comparing data by ANOVA from the dirithromycin treatment period with that of the placebo treatment period. On the other hand, during dirithromycin treatment astemizole CL(oral) was 34% slower, volume of distribution was 24% larger, and half-life was 84% longer. Generally, all QT ( c ) intervals did not appear to be affected by dirithromycin treatment. The changes in astemizole kinetics could not be attributed to its N-demethylation since the dispositional kinetics of N-desmethylastemizole were unaffected by dirithromycin. Therefore, it is difficult to ascertain the clinical significance of the changes in astemizole kinetics. Since there were no significant differences for mean QT(c) intervals and no effect of dirithromycin treatment on N-desmethylastemizole kinetics, it is unlikely that a standard regimen of dirithromycin would place a patient taking astemizole at an increased risk of torsade de pointes or related ventricular arrhythmias.

Adolescent↗
PubMedDate not supplied

Effects of allocare-givers on fitness of infants and parents in callitrichid primates.

The effects of callitrichid primate helpers (allocare-givers other than an infant's father) on the survival, reproduction or behavior of infants and parents are reviewed, using both published studies and data from free-ranging golden lion tamarins (Leontopithecus rosalia). Three lines of evidence suggest that helpers may increase their own inclusive fitness: (1) The number of adult males acting as helpers in free-ranging groups is correlated with the number of surviving infants in 3 callitrichid species. However, the lack of a negative correlation with number of infants dying suggests that activities other than direct infant care (e.g. territory defense) may be more important, especially in newly formed groups. (2) In 2 species, captive groups with helpers carry infants for longer periods of time than do groups without helpers. Whether such differences would translate into meaningful survival differences in free-ranging groups is unclear. (3) Helpers reduce the energetic burden of parents by reducing the amount of time they spend transporting or provisioning infants in at least 4 species. Reproductive males are more likely than reproductive females to benefit from the presence of helpers, reducing their investment in infant care activities as the number of helpers in the group increases. In free-ranging golden lion tamarins, the reproductive tenure of males, but not females, increases with the number of helpers in the group, suggesting that a reduction in energetic investment may translate into increased survival. 'Decisions' made by helpers to participate in infant transport are weighed against competing needs for foraging, vigilance, territory defense and, in some cases, prospecting for breeding opportunities. Given this complexity, a sophisticated model may be required to answer the question of how helpers 'decide' to participate in infant care versus other activities.

Animals↗
PubMedDate not supplied

Incomplete recovery of chicken distortion product otoacoustic emissions following acoustic overstimulation.

Distortion product otoacoustic emissions (DPOAEs) were measured in chickens before and after exposure to a 525-Hz pure tone (120 dB SPL, 48 h). The exposure caused extensive hair cell loss and destroyed the tectorial membrane along the abneural edge of the basilar papilla in the low-to-mid-frequency region of the cochlea. Although the lesion was restricted, DPOAEs were greatly depressed at all frequencies immediately after the exposure. The high-frequency DPOAEs gradually recovered to preexposure values after the exposure; however, there was little or no improvement in DPOAEs at test frequencies equal to or slightly above the exposure frequency even after 16 weeks of recovery. By 28 days of recovery, the previously damaged region of the basilar papilla had been repopulated by hair cells and the lower honeycomb layer of the tectorial membrane had regenerated, but not the upper fibrous layer. The upper fibrous layer of the tectorial membrane was still missing after 16 weeks of recovery and the region of damage corresponded closely to the frequency regions where the DPOAEs were depressed.

Acoustic Stimulation↗
PubMedDate not supplied

Mechanical complications from insertion of subclavian venous feeding catheters: comparison of de novo percutaneous venipuncture to change of catheter over guidewire.

Since a percutaneous catheter insertion into the subclavian vein can be tedious, time consuming, and risky, we have compared the morbidity of 137 de novo subclavian catheter insertions to that of 93 reinsertions over guidewire. Mechanical complications were significantly higher (p less than 0.03) in those with catheter insertions (8.8%) than in those with the guidewire insertions (2.2%). These included pneumothorax (4), arterial puncture (4), catheter-size bleed (3), and hemothorax (1) in the catheter insertion group and local bleeding (1) and hydrothorax (1) in the guidewire insertion group. The difference in complications between methods is probably inherent in the techniques. Operator experience was not a factor: 55% of the physicians in each group had previously done less than 26 subclavian venous catheterizations. Preliminary analysis indicates that the infection rate, as determined by semiquantitative, cultures, is the same in each group. When considering the equal potential for infection, we conclude that change over a guidewire is an acceptable alternative to contralateral de novo percutaneous subclavian venipuncture for feeding catheter insertion. In view of fewer mechanical complications and greater ease of insertion, change of subclavian feeding catheters by guidewire is probably the method of choice.

Arteries↗
PubMedDate not supplied

Use of the health history as a psychiatric screening tool.

BACKGROUND: Numerous studies indicate that most mental health services are provided in the primary care medical setting and that problems exist with misdiagnoses and lack of recognition of mental health disorders. The purpose of our investigation was to determine whether patient responses on a typical medical health history form could be used to predict depression or anxiety. METHODS: New adult patients at a university community family practice clinic were surveyed during a 6-month period. Study patients completed a health history form and standardized inventories of anxiety and depression. RESULTS: The study sample included 187 patients. Positive responses to mood-related symptoms reported on the health history best predicted anxiety and depression. Nonmood symptoms were also significant, although not as powerful, predictors of these disorders. A significant relation existed between total number of positive symptoms and psychiatric diagnoses, which continued when mood symptoms were removed from the analyses. Results were used to develop physical, nonmood primary care symptom profiles that could be used to screen for anxiety and depression. CONCLUSION: Providing physicians the means to improve mental health diagnostics can help advance patient care and health care system outcomes.

Adult↗
PubMedDate not supplied

A performance test to accompany ophthalmic examination in the young school age child: the "draw a bicycle" test.

A performance test is proposed as an addition to the routine eye examination of the child performing poorly in school. Performance on the "draw a bicycle test" has a strong correlation with academic performance among children in grades one through three. Poor performance on the "draw a bicycle test" by children who have otherwise normal eye findings implicates a non ocular cause for the poor academic performance. Since the results of this simple test are immediately visible and readily understood by an attending parent, the ophthalmologist's role in counseling the parents against further ocular investigation and therapy is apparent.

Child↗