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Biomedical subjects

J Kaiser

Publications and source records attributed to J Kaiser.

At least 91 records · Page 5Linked to original sources
PubMed2000

Statistical probability mapping reveals high-frequency magnetoencephalographic activity in supplementary motor area during self-paced finger movements.

Investigations of both haemodynamic and electroencephalographic measures of brain activity have demonstrated supplementary motor area (SMA) involvement in self-paced finger movements. In contrast, analysis of magnetoencephalographic (MEG) signals in the time domain has usually failed to detect SMA activity in healthy individuals. We investigated oscillatory MEG activity in 12 normal adults during (a) a self-paced, complex sequence of finger movements and (b) a simple finger opposition task paced externally by tactile stimuli presented to the contralateral thumb. Statistical probability mapping revealed enhanced non-phase-locked spectral amplitudes in the 22-28 Hz range over bilateral frontal cortex during self-paced as compared to externally cued finger movements. This activity may reflect recruitment of cell assemblies in SMA during self-paced, complex movements.

Adult↗
PubMed2000

Role of health communications in Russia's diphtheria immunization program.

As part of a broader program in health communication assistance, project staff from Basic Support for Institutionalizing Child Survival worked with staff from Russia's oblast (regional) public health agencies to design and implement communication activities supporting local diphtheria immunization efforts. Because aggressive community outreach efforts and strong administrative sanctions had already achieved impressive adult coverage rates for first doses of diphtheria toxoid vaccine, communication interventions emphasized the need for second and third doses. Outcomes were assessed through vaccination coverage data and more qualitative measures. In one project site, the increase in adult coverage (two or more doses) was very modest. In a second site, with a stronger communications component, coverage increased significantly (from 20% to 80%). Although it is not possible to disentangle completely the effects of communications from other aspects of oblast immunization programs, these and other outcome data suggest that health communications can play an important role in Russia's ongoing mass immunization efforts.

Adult↗
PubMed2000

Clinical application of laser-induced breakdown spectroscopy to the analysis of teeth and dental materials.

OBJECTIVES: The luminous plasma generated during laser ablation of dental tissue and dental materials has been analyzed to determine qualitative and quantitative elemental composition. BACKGROUND DATA: The use of pulsed lasers for controlled material ablation now is frequently suggested as an alternative to mechanical drilling for the removal of caries and in tooth modification. Spectral analysis of the ablated plasma can be exploited to monitor precisely the laser drilling process in vivo and in real time. METHODS: Teeth samples and dental materials were ablated using pulses from a Nd:YAG laser. The line positions and intensities in the spectra, recorded in real time, were used to identify elements and to determine their relative concentrations. RESULTS: From the spectra of horizontally and vertically cut tooth slices, profiles of elemental distribution were determined; these were used in a range of monitoring applications. We showed that the transition from caries to healthy tooth material could be identified through the decrease in calcium (Ca) and phosphorus (P) concentrations, whereas nonmineralizing elements and organic materials increased in concentration. We also could relate the spatial distribution of elements to their migration or accumulation over time, for example, the migration of aluminium (Al) from dental restorative materials to the tooth matrix. CONCLUSIONS: The plasma existing during laser ablation (in vitro/in vivo) can be analyzed spectrally in real time. From the spectra, one can pinpoint high/low levels of element concentrations within the tooth matrix. Thus, this analysis could be used to monitor the ablation of material during laser dental treatment.

Adult↗
PubMed2000

The thought translation device (TTD) for completely paralyzed patients.

The thought translation device trains locked-in patients to self-regulate slow cortical potentials (SCP's) of their electroencephalogram (EEG). After operant learning of SCP self-control, patients select letters, words or pictograms in a computerized language support program. Results of five respirated, locked-in-patients are described, demonstrating the usefulness of the thought translation device as an alternative communication channel in motivated totally paralyzed patients with amyotrophic lateral sclerosis.

Biofeedback, Psychology↗
PubMed2000

Reduced risk of upper gastrointestinal ulcer complications with celecoxib, a novel COX-2 inhibitor.

OBJECTIVE: The aim of this study was to assess the rate of upper gastrointestinal (UGI) ulcer complications (bleeding, perforation, or gastric outlet obstruction) associated with celecoxib, a specific COX-2 inhibitor, compared with the rate associated with nonspecific, nonsteroidal anti-inflammatory drugs (NSAIDs). METHODS: A pooled analysis was conducted of 14 multicenter, double-blind, randomized, controlled trials (RCTs) and a separate analysis of one long-term open label trial that assessed the efficacy and safety of celecoxib for symptomatic treatment of arthritis. The RCTs enrolled 11,008 patients with osteoarthritis or rheumatoid arthritis treated for 2-24 wk; the long-term open label trial enrolled 5,155 patients receiving celecoxib for a maximum of 2 yr. In the RCTs, patients were randomly assigned to receive placebo (n = 1,864; 208 patient-years), celecoxib 25-400 mg b.i.d. (n = 6,376; 1,020 patient-years), or a comparator NSAID (n = 2,768; 535 patient-years); NSAIDs were naproxen 500 mg b.i.d., diclofenac 50 or 75 mg b.i.d., or ibuprofen 800 mg t.i.d.). In the long-term, open-label trial, patients received celecoxib 100-400 mg b.i.d. for up to 2 yr (n = 5,155; 5,002 patient-years). The principal outcome measure of this analysis was development of a UGI ulcer complication, which was prospectively defined as bleeding, perforation, or gastric outlet obstruction. Ulcer complications were assessed and adjudicated by persons blinded to the patient's treatment assignment or the study in which the patient participated. RESULTS: In the RCTs, UGI ulcer complications occurred in no placebo patients (0 of 1,864 patients), in 2 of 6,376 celecoxib patients (0.03%), and in 9 of 2,768 patients receiving an NSAID (0.33%), corresponding to annual incidences of 0.20% for celecoxib (p > 0.05 vs placebo) and 1.68% for NSAIDs (p = 0.002 vs celecoxib and placebo). In the long-term open-label trial, nine UGI ulcer complications occurred, for an incidence of 0.17% and an annualized incidence of 0.18%. CONCLUSIONS: The incidence of UGI ulcer complications associated with celecoxib was 8-fold lower than with nonspecific NSAIDs. The incidence of ulcer complications observed in celecoxib-treated patients was similar to that in patients receiving placebo in the RCTs, and to that in non-NSAID users reported in the literature.

Adolescent↗
PubMed2000

Strategies to maximize retention of a sample of young adolescents in a longitudinal evaluation of Healthy & Alive!

The authors implemented strategies to maximize cohort retention to avert loss of statistical power and minimize bias in a longitudinal evaluation of a middle school HIV/STD prevention intervention. A retention rate of 80% of the baseline sample (n = 2,975) at six months and 73% at 18 months was achieved despite high reported rates of student mobility and a major system reorganization in one urban district. The strategies increased retention but did not eliminate differences in demographic characteristics and behaviors between the groups of retained and lost students. Results confirm the need to implement retention strategies early and to maintain them throughout data collection. Information from a tracking data base can be used to prioritize students for follow-up to reduce bias from sample loss.

Adolescent↗