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Biomedical subjects

G Rose

Publications and source records attributed to G Rose.

At least 55 records · Page 3Linked to original sources
PubMed1997

Characteristics and clinical value of an intravenous echo-enhancement agent in evaluation of high-grade internal carotid stenosis.

Although ultrasound is a highly useful tool for clinical diagnosis, it has certain limitations in accurately quantifying internal carotid stenosis or diagnosing internal carotid occlusion. However, these limitations can be overcome by increasing the echogenicity of flowing arterial blood by use of echo-enhancement agents. Two phase III studies assessed the usefulness of the IV transpulmonary echo enhancer Levovist (SH U 508A) in improving characterization and quantification of severe internal carotid stenosis on ultrasound scans. In addition, Levovist-induced enhancement characteristics of the Doppler frequency spectrum have been analyzed. To be included in the study reviewed here, patients had to have a high-grade (> or = 70%) stenosis or occlusion of an internal carotid artery (ICA), as judged by conventional angiography or by standard cervical Doppler ultrasound. Patients were excluded from consideration if they were pregnant or nursing, had a history of galactosemia, or had received an ionic contrast medium within 24 hours before or after the intended administration of Levovist. Written informed consent was obtained from all patients before entry into the study. Of 32 patients (14 women, 18 men, median age 64 yr) who were included in this study, high-grade stenosis was verified in 30 ICA vessels and occlusion was verified in two vessels. After admission into the study, the carotid bifurcation was insonated in all patients using a 7.5-MHz linear array transducer for color Doppler-assisted duplex imaging and a 4-MHz pulsed-wave Doppler for velocity spectrum measurements before and after injection of the echo enhancement agent Levovist. Levovist-induced increases in carotid blood echogenicity began 11 +/- 2 seconds (mean +/- SD) after the start of injection, peaked at 21 +/- 2 dB, and had a half-life of 75 seconds. A fast Fourier transform of the original Doppler velocity spectrum demonstrated Levovist-induced enhancement throughout the entire velocity spectrum, with an increase in ICA blood flow velocity paralleling an increase in reflected ultrasound energy. Quantitative vascular measurements (cross-sectional luminal area reduction and plaque length) obtained before and during echo enhancement were highly correlated (r > 0.90). However, visualization of the entire length of the intrastenotic residual flow lumen, was significantly improved by Levovist enhancement (52% versus 83%; p = 0.01). Levovist considerably increased interpretable data by improving image quality in patients with high-grade carotid stenosis. Furthermore, the significant improvement in visualization of the residual flow lumen suggests that echo-enhancement agents may be most useful in improving the ultrasonography-based diagnosis of internal carotid occlusion.

Blood Flow Velocity↗
PubMed1996

Evaluation of household dust mite exposure and levels of specific IgE and IgG antibodies in asthmatic patients enrolled in a trial of immunotherapy.

BACKGROUND: Monitoring the response to immunotherapy entails understanding exposure to relevant allergens. For the major indoor allergens, this requires sampling of dust from the patient's house. The objectives of this study were to measure indoor allergen levels during a controlled trial of dust mite immunotherapy for asthma and to relate these results to serum antibody levels. METHODS: Eighty-eight asthmatic patients with mite allergy from seven geographic areas in the United States were enrolled in and completed a course of immunotherapy with Dermatophagoides extract or placebo control. Sensitization was evaluated by quantitative measurements of IgG and IgE antibodies. Dust samples were assayed for group I mite (Der p 1 and Der f 1), cat (Fel d 1), and cockroach (Bla g 1) allergens by monoclonal antibody-based ELISA. RESULTS: Over the 4 years of the study, each of the houses had at least one sample that contained more than 2 micrograms of group I mite allergen per gram of dust. Mean mite allergen levels, however, varied over a wide range, from 0.2 microgram/gm or less to more than 50 micrograms/gm. IgE antibodies to mite were present in sera from 78% of the patients, whereas IgE antibodies to cat and cockroach allergens were found in sera from 34% and 11% of patients, respectively. Sixty-four percent of the patients had exposure and sensitization to mite, whereas the comparable figure for each of the other allergens was 5%. CONCLUSIONS: Examination of the results suggested that allergen exposure, relative to a trial of immunotherapy, could be expressed as (1) the maximum level found in the house, (2) the percentage of sites having greater than 2 micrograms/gm, or (3) the mean value at the site with the maximum level. This report provides a background for evaluating the clinical results of immunotherapy in these patients and a model for the way in which sensitization and exposure should be monitored in studies of this kind.

Adolescent↗
PubMed1996

Spinal neostigmine diminishes, but does not abolish, hypotension from spinal bupivacaine in sheep.

Spinal neostigmine causes analgesia in animals and humans and abolishes hypotension from spinal bupivacaine in rats. Since drug distribution and action can vary with the size of the spinal cord, we tested the effects of the maximum tolerated dose of spinal neostigmine alone and with bupivacaine in conscious sheep. Neostigmine alone increased arterial blood pressure by 10%, with a statistically significant increase beginning 30 min after injection. Compared with spinal bupivacaine alone, addition of neostigmine resulted in hypotension of slower onset (15 vs 5 min), shorter duration (45 vs 105 min), and smaller magnitude (-18% +/- 3% vs -37% +/- 6%). Addition of neostigmine did not affect height of sensory block from spinal bupivacaine. These data agree with preliminary clinical reports that spinal neostigmine diminishes, but does not abolish, hypotension from spinal bupivacaine in humans.

Analgesia↗
PubMed1996

How good is intercenter agreement in the identification of embolic signals in carotid artery disease?

BACKGROUND AND PURPOSE: There has been concern regarding the reproducibility of the detection of embolic signals, particularly in patients with carotid artery stenosis in whom the signals are of low intensity. No published studies have examined inter-center agreement in reporting specific embolic signals or the factors responsible for any lack of agreement. We examined reproducibility between two centers in which widely differing proportions of embolic signals have previously been reported in patients with carotid artery stenosis. METHODS: Recordings from the middle cerebral artery of eight patients with ipsilateral carotid artery stenosis in whom embolic signals had been detected during a previously study were independently examined by three experienced observers in one center and by one experienced observer in another center. We calculated agreement within and between centers by estimating the probability that one observer would identify a specific embolic signal if other observers had identified it (a probability of 1 indicates complete agreement). The influence of different characteristics of the embolic signal on the probability of its detection as an embolic signal was determined. RESULTS: A high level of agreement in the identification of specific embolic signals was found. This was similar between all observers (.90), between the three observers in one center (.89), and between observers in the two different centers (.94). The probability of detection was independently related to the relative intensity of the embolic signal (P<.0001). It was less (although significantly) independently related to the position of the embolic signal in the cardiac cycle (P=.02), with signals in systole being more reliably detected. There was no independent relationship between the probability of detection and either the duration of the embolic signal or the velocity at the maximum intensity increase. The use of threshold intensity as a criterion for embolic signal detection increased interobserver agreement but reduced the sensitivity in detecting signals. CONCLUSIONS: The high level of interobserver agreement suggests that the technique is sufficiently reproducible for clinical use.

Blood Flow Velocity↗
PubMed1996

Effects of a health examination programme on quality of life and subjective well-being.

The effects on quality of life and psychological well-being of a health examination programme in a branch of Swedish industry were studied by means of questionnaires in 124 white-collar workers. They were asked to answer two questionnaires, one before and the other one month after the examination (the Nottingham Health Profile (NHP) and the Psychological General Well-being Schedule (PGWB)). Both are well-known and well-documented standard questionnaires used for estimating quality of life and degree of subjective well-being. The answers were compared with those of a control group comprising other white-collar workers in the same industry, of the same sex and age but who did not participate in the health examination and who were asked to complete the same questionnaires twice. The group that had participated in the health examination did not differ generally from the control group with respect to intra-individual differences as studied in the questionnaires on the two occasions. This indicates that no deterioration of quality of life or of psychological well-being was experienced by the participants in the health examination.

Adult↗
PubMed1996

The specificity of autobiographical memory and imageability of the future.

Three studies examined whether the specificity with which people retrieve episodes from their past determines the specificity with which they imagine the future. In the first study, suicidal patients and nondepressed controls generated autobiographical events and possible future events in response to cues. Suicidal subjects' memory and future responses were more generic, and specificity level for the past and the future was significantly correlated for both groups. In the second and third studies, the effect of experimental manipulation of retrieval style was examined by instructing subjects to retrieve specific events or summaries of events from their past (Experiment 2) or by giving high- or low-imageable words to cue memories (Experiment 3). Results showed that induction of a generic retrieval style reduced the specificity of images of the future. It is suggested that the association between memory retrieval and future imaging arises because the intermediate descriptions used in searching autobiographical memory are also used to generate images of possible events in the future.

Adolescent↗
PubMed1996

Allele frequency distributions at seven DNA hypervariable loci in a population sample from Calabria (southern Italy).

Genotype and allele frequencies at seven Variable Number of Tandem Repeats (VNTR) loci currently used for forensic purposes have been estimated in a population sample from Calabria (south Italy). DNA target regions relevant to four microsatellites (THO.1; REN.4; D12S67; DYS19) and three minisatellites (D1S80; 3'APOB; TPO.10) were amplified by Polymerase Chain Reaction (PCR) and analysed by electrophoresis and ethidium bromide or silver staining. For all loci, the observed genotypes were found to be in agreement with those expected by the Hardy-Weinberg equilibrium. Data on allele frequencies were in line with those found in sample groups from northern or central Italy, tested for some of the above polymorphisms.

Adolescent↗
PubMed1995

The influence of flavor and color on drink identification by children and adults.

This study investigated how color and flavor influences drink identification by children and adults. The children ranged in age from 2 to 18 years of age. Each subject tasted four drinks that differed in color and flavor. Each drink had an atypical color-flavor pairing (e.g., brown-pineapple) or a typical pairing (e.g., brown-chocolate). After tasting each drink, the subject chose which of four flavor names identified the drink. For the atypical drinks, the selection of color-associated names (e.g., chocolate for a brown drink) decreased, and the selection of flavor-associated names increased with age from the preschoolers to the adults. For the typical drinks, the selection of the correct name was greater than 80% for all ages. These results suggest that drink identification becomes more influenced by flavor as children get older because of an increase in the ability of children to focus on flavor as their perceptual-attentional skills mature.

Adolescent↗
PubMed1995

Cooperative effects of neuronal ensembles.

Electrophysiological properties of neurons as the basic cellular elements of the central nervous system and their synaptic connections are well characterized down to a molecular level. However, the behavior of complex noisy networks formed by these constituents usually cannot simply be derived from the knowledge of its microscopic parameters. As a consequence, cooperative phenomena based on the interaction of neurons were postulated. This is a report on a study of global network spike activity as a function of synaptic interaction. We performed experiments in dissociated cultured hippocampal neurons and, for comparison, simulations of a mathematical model closely related to electrophysiology. Numeric analyses revealed that at a critical level of synaptic connectivity the firing behavior undergoes a phase transition. This cooperative effect depends crucially on the interaction of numerous cells and cannot be attributed to the spike threshold of individual neurons. In the experiment a drastic increase in the firing level was observed upon increase of synaptic efficacy by lowering of the extracellular magnesium concentration, which is compatible with our theoretical predictions. This "on-off" phenomenon demonstrates that even in small neuronal ensembles collective behavior can emerge which is not explained by the characteristics of single neurons.

Animals↗
PubMed1995

Quantitative assessment of exposure to dog (Can f 1) and cat (Fel d 1) allergens: relation to sensitization and asthma among children living in Los Alamos, New Mexico.

BACKGROUND: Our objective was to identify the allergens associated with asthma among schoolchildren in an area of the United States where dust mite growth is expected to be poor. Los Alamos, N.M., was chosen because it has low rainfall and is at high altitude (7200 feet) making it very dry. One hundred eleven children (12 to 14 years old) from the middle school who had been previously classified according to bronchial hyperreactivity to histamine (BHR) were studied. METHODS: Sera were assayed for IgE antibodies to mite, cat, dog, cockroach, Russian thistle, and grass pollen, with both CAP system fluoroimmunoassay (Kabi Pharmacia, Uppsala, Sweden) and conventional RAST. Allergens were measured in dust samples from 108 homes with two-site assays for mite (Der p 1 and Der f 1), cat (Fel d 1), dog (Can f 1), and cockroach (Bla g 2). RESULTS: Concentrations of dog and cat allergens were elevated in almost all houses with pets but were also high in a significant proportion of the houses without pets. Levels of mite allergen were less than 2 micrograms/gm in 95% of the houses, and cockroach was undetectable in all but two of the houses. Among the 21 with BHR who had symptoms, 67% had IgE antibody to dog and 62% had IgE antibody to cat. For these allergens IgE antibody was strongly associated with asthma (p < 0.001). By contrast, the presence of IgE antibody to mite, cockroach, or grass pollen was not significantly associated with asthma. CONCLUSION: The high prevalence of IgE antibody to cat and dog allergens among these children is in keeping with the presence of cat and/or dog allergen in most of the houses. Furthermore, sensitization (as judged by IgE antibodies) to cat and dog allergens was strongly associated with asthma. On the other hand, no clear relationship was found between sensitization or symptoms and the current level of allergen in individual houses. The results show that in this mite-and cockroach-free environment sensitization to domestic animals was the most significant association with asthma.

Adolescent↗
PubMed1995

Someone who cares--patients' experiences concerning health examinations.

The aim of this inquiry was to gain an understanding of laymen's experiences and opinions about general health check-ups. Medical experts often draw attention to unwanted effects, especially the risk of creating worry and of recommending and even giving unnecessary medical treatment. By using a qualitative research method with unstructured interviews we wanted to explore the participants' conceptions of health, their expectations before and their perceived benefits after health checks and whether the check-up gave rise to negative feelings. The participants held broad views on health and, possibly as a consequence, also great expectations of health check-ups. Consequences of the check-ups were that examinees felt encouraged to change their life style, had learnt to handle risk factors for disease, and after some time, reported feeling better. The individual attention and care, which in general did not differ from other caring situations described in the literature, was highlighted as an important factor for a positive result. Worries afterwards either did not exist or could be rationalized by knowing the causes of abnormalities and receiving guidance from the medical staff.

Adult↗
PubMed1995

Cerebral microembolism and the risk of ischemia in asymptomatic high-grade internal carotid artery stenosis.

BACKGROUND AND PURPOSE: Previous work has shown that cerebral microembolism detected with transcranial Doppler sonography distal to internal carotid artery stenosis occurs more frequently in recently symptomatic compared with asymptomatic patients. It has remained unclear whether cerebral microembolism also indicates a higher risk of future cerebral or retinal ischemia. SUMMARY OF REPORT: Sixty-four asymptomatic patients with unilateral 70% to 90% internal carotid artery stenosis were investigated prospectively (mean follow-up, 72 weeks). Five patients developed ischemic symptoms attributable to the stenosis (transient ischemic attack, 2 patients; stroke, 3 patients). A microembolic rate of > or = 2 per hour in the ipsilateral middle cerebral artery was associated with a substantially increased risk of developing ischemia of the corresponding carotid territory (odds ratio, 31; 95% confidence interval, 3 to 302; P = .005). CONCLUSIONS: This prospective pilot study suggests that cerebral microembolism detected with transcranial Doppler sonography may define a high-risk subgroup among patients with asymptomatic high-grade internal carotid artery stenosis.

Aged↗
PubMed1995

Cheyne-Stokes respiration in ischemic stroke.

We monitored breathing pattern and arterial oxygen saturation in 32 conscious patients with acute ischemic stroke. Seventeen (53%) had Cheyne-Stokes respiration with concomitant drops in oxygen saturation, unrelated to infarct location. The ventilatory disturbance promptly reversed after intravenous theophylline ethylenediamine or oxygen inhalation. The therapy is a simple way of improving arterial oxygenation in a large subgroup of patients with acute ischemic stroke.

Adult↗
PubMed1994

Alcohol and blood pressure: the INTERSALT study.

OBJECTIVES: To assess the relation between alcohol intake and blood pressure in men and women and in men at younger and older ages; to examine the influence of amount and pattern of alcohol consumption, as well as of acute effects, taking into account body mass index, smoking, and urinary sodium and potassium excretion. DESIGN: Subjects reported alcohol consumption for each of seven days before standardised blood pressure measurement, and whether they had consumed any alcohol in the 24 hours before measurement. SETTING: 50 centres worldwide. SUBJECTS: 4844 men and 4837 women aged 20-59. MAIN OUTCOME MEASURES: Effect of alcohol on blood pressure estimated by taking a weighted average of regression coefficients from centres. Acute effect assessed by examining mean differences in blood pressure of non-drinkers and of heavy drinkers who had and had not consumed alcohol in the 24 hours before measurement. Effect of pattern of consumption assessed by examining mean differences in blood pressure of non-drinkers compared with drinkers (i) whose intake was concentrated in fewer days or who were drinking more frequently, and (ii) whose alcohol intake varied little over the seven days or varied more substantially, as indicated by the standard deviation of daily consumption. RESULTS: Of the 48 centres in which some people reported consuming at least 300 ml/week of alcohol, 35 had positive regression coefficients linking heavy alcohol consumption to blood pressure. Overall, alcohol consumption was associated with blood pressure, significantly at the highest intake. After account was taken of key confounders, men who drank 300-499 ml alcohol/week had systolic/diastolic blood pressure on average 2.7/1.6 mmHg higher than non-drinkers, and men who drank > or = 500 ml alcohol/week had pressures of 4.6/3.0 mmHg higher. For women, heavy drinkers (> or = 300 ml/week) had blood pressures higher by 3.9/3.1 mmHg than non-drinkers. Heavy drinking and blood pressure were strongly associated in both sexes, and in men at both younger (20-39 years) and older (40-59 years) ages. In men who were heavy drinkers, episodic drinkers (those with great variation in daily alcohol consumption) had greater differences in blood pressure compared with non-drinkers than did regular drinkers of relatively constant amounts. CONCLUSION: The significant relation of heavy drinking (3-4 or more drinks/day) to blood pressure, observed in both men and women, and in younger and older men, was independent of and added to the effect on blood pressure of body mass index and urinary excretion of sodium and potassium. The findings indicate the usefulness of targeting those at high risk as well as the general population to reduce the adverse effects of alcohol on blood pressure.

Adult↗
PubMed1994

The assessment of biological age: a report from the Department of Environment Study.

Indicators of ageing were measured in 397 male and 130 female London Civil Servants aged from 37 to 58 years of age. Grey hair, skin inelasticity, and arcus senilis were strongly and independently related to chronological age. Also independently related were serum albumin (negatively related in both sexes), baldness, serum creatinine, systolic blood pressure, serum calcium (negatively) and ESR in men, and serum cholesterol in women. Chronological age was regressed on the above variables for men and women separately to provide regression equations. Biological age for an individual was calculated by entering his or her results and calculating the residuals. Biological age in those who stopped smoking tended to be younger than chronological age by an average of 12-13 months in men and 1-4 months in women. Men and women who had never smoked had higher biological than actual ages but not after adjusting for regression dilution bias. Men who currently smoked had higher biological ages of 2-3 months but not women smokers (4-6 months lower). Similarly, men of lower employment grades had an average biological age 13 months older and women 8 months, compared with higher employment grades. These differences between employment grade appeared to be due to ESR, arcus senilis, systolic blood pressure and serum cholesterol. These four measurements may be markers of biological rather than chronological age, and the value of attempting to measure biological age is discussed.

Adult↗
PubMed1994

Chemical treatment of carpets to reduce allergen: a detailed study of the effects of tannic acid on indoor allergens.

Tannic acid (TA), a protein-denaturing agent, has been reported to reduce allergen levels in house dust and is marketed for that purpose as 1% and 3% solutions. We investigated the effects of TA on dust allergens by using monoclonal antibody-based ELISAs for mite (Der p I, Der f I, and group II) and cat (Fel d I) allergens. Initial studies confirmed that TA reduced allergen levels in carpet dust. However, when dust samples from treated carpets are extracted in saline solution, residual TA redissolves and may interfere with the assessment of allergens. In the laboratory, concentrations of TA as low as 0.1% inhibited the assays, but this effect may be prevented by addition of 5% bovine serum albumin (BSA). After treatment of dust samples in the laboratory with 3% TA, the apparent reductions in Der p I and Der f I levels were 89% and 96%, respectively, but when the samples were extracted in 5% BSA the reductions were 74% and 92%. Similar effects were seen with dust samples from carpets treated with TA. In an extreme case in which a carpet had been repeatedly treated with TA, the apparent concentration of Der p I was < 0.05 microgram/gm without BSA and 2.1 and 8.4 microgram/gm when extracted in the presence of 1% and 5% BSA, respectively. Our testing of the ability of TA to denature Fel d I demonstrated an 80% reduction in allergen, but only in samples with an initial concentration of less than 200 micrograms Fel d I/gm dust.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollution, Indoor↗
PubMed1994

Real-time identification of cerebral microemboli with US feature detection by a neural network.

PURPOSE: Abnormal transcranial Doppler ultrasonographic (US) signals indicating cerebral microembolism have characteristic but complex features. The authors wanted to assess the agreement among human observers and test the feasibility of an automated detection system. MATERIALS AND METHODS: Automated on-line detection of cerebral microemboli was accomplished by employing real-time overlapping Fourier transform and artificial neural network technology. By using long-term transcranial Doppler US recordings of the middle cerebral artery in consecutive cerebrovascular and cardiac patients, the method was evaluated in a clinical setting. RESULTS: The proportion of specific agreement (ps) among four experienced investigators identifying cerebral microemboli was high (mean ps, 0.91). Agreement among the neural network and the human observers was only slightly less (mean ps, 0.77). CONCLUSION: The technique allows highly reliable on-line evaluation of transcranial Doppler US recordings across multiple centers. It obviates time-consuming analyses by human observers.

Humans↗