Motor neuron disease presenting as acute respiratory failure: electrophysiological studies.
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Aged↗
Biomedical subjects
R Chen
Publications and source records attributed to R Chen.
Involvement of the ipsilateral motor cortex in finger movements of different complexities.
Functional imaging and behavioral studies suggest involvement of the ipsilateral hemisphere in hand movements, particularly of the left hand. If this is so, transient disturbance of the motor cortex (M1) with repetitive transcranial magnetic stimulation (rTMS) may affect ipsilateral motor sequences, and the effects may differ on the two sides. We studied 15 right-handed subjects who played a simple and a complex piano sequence for 8 seconds each. Two seconds after the beginning of each sequence, rTMS was delivered to the ipsilateral or contralateral M1, or directed away from the head (control trial). Ipsilateral M1 stimulation on either side induced timing errors in both sequences, and with the complex sequence induced more timing errors in the left hand than in the right hand. Errors of the right hand with both sequences occurred in the stimulation period only, but errors of the left hand with the complex sequence occurred in both the stimulation and poststimulation periods. We conclude that the ipsilateral M1 is involved in fine finger movements. The left hemisphere plays a greater role in timing ipsilateral complex sequences than the right hemisphere and may be more involved in the processing of complex motor programs.
Adult↗
An apoptosis-inducing genotoxin differentiates heterozygotic carriers for Werner helicase mutations from wild-type and homozygous mutants.
Immortalized B lymphocytes from Werner syndrome subjects are shown to be hypersensitive to 4-nitroquinoline-1-oxide (4NQO), supporting earlier work on T lymphocytes. We also show that B cell lines from clinically normal heterozygous carriers exhibit sensitivities to this genotoxic agent, which are intermediate to those of wild-type and homozygous mutants. 4NQO is shown to induce an apoptotic response. These data encourage research on DNA repair with such cell lines and raise the question of an enhanced sensitivity of the relatively prevalent heterozygous carriers to certain environmental genotoxic agents.
4-Nitroquinoline-1-oxide↗
Efficacy and safety of loratadine plus pseudoephedrine in patients with seasonal allergic rhinitis and mild asthma.
BACKGROUND: Antihistamines have been shown to have a variety of therapeutic effects in asthma. Although nasal obstruction may play an important role in modulating lower airway function, no prior trial has used a decongestant in combination with an antihistamine in patients with allergic rhinitis and concomitant asthma. OBJECTIVE: We sought to determine the efficacy and safety of loratadine (5 mg) plus pseudoephedrine (120 mg) (L/P) twice daily in patients with seasonal allergic rhinitis and mild asthma. METHODS: We conducted a randomized, double-blind, placebo-controlled trial of L/P in 193 subjects during the fall allergy season. Nasal and chest symptoms, albuterol use, and peak expiratory flow rates were recorded daily for 6 weeks. Spirometry was measured at baseline and after 1, 2, 4, and 6 weeks of therapy, and health-related quality of life was rated at the beginning and end of the study. RESULTS: Total rhinitis and asthma symptom severity scores were significantly reduced in patients receiving active therapy compared with those receiving placebo throughout the 6-week study. Peak expiratory flow rates improved significantly in patients treated with L/P during weeks 2 through 6 (peak effect [mean +/- SEM]: L/P, 26.23 +/- 4.64 L/min vs placebo, 8.52 +/- 3.53 L/min, p = 0.002) as did FEV1 (peak effect [mean +/- SEM]: L/P, 170 +/- 53 ml vs placebo, 20 +/- 40 ml, p = 0.01) at all clinic visits. In addition, select measures of asthma-specific quality of life improved significantly relative to placebo. CONCLUSIONS: L/P significantly improved nasal and asthma symptoms, pulmonary function, and quality of life in patients with seasonal allergic rhinitis and concomitant mild asthma.
Adolescent↗
Safety of different inter-train intervals for repetitive transcranial magnetic stimulation and recommendations for safe ranges of stimulation parameters.
Induction of a seizure in a normal subject with trains of repetitive transcranial magnetic stimulation (rTMS) applied in close succession suggested that short inter-train intervals, a parameter not considered in our previous safety studies, may not be safe. Here, we evaluate the safety of different inter-train intervals for rTMS in 10 healthy volunteers. Ten rTMS trains at 20 Hz for 1.6 s and a stimulus intensity of 110% of motor threshold (MT) were found to be safe at the inter-train interval of 5 s. However, inter-train intervals of 1 s or less were unsafe for trains of 20 Hz for 1.6 s and stimulus intensities higher than 100% of MT. Based on these results, we propose safety guidelines for inter-train intervals at different stimulus intensities. We also analyzed the stimulus parameters, used in 3 studies, that led to seizures in normal subjects. One seizure was due to short inter-train intervals, one was likely related to intense individual rTMS trains close to the limit of our previous safety recommendations, and one was likely due to a combination of these two factors. To provide an additional safety margin, we suggest reducing the duration for individual rTMS trains by 25% from our previous recommendations. Updated safety tables currently in use at our institution are provided.
Adult↗
Role of the ipsilateral motor cortex in voluntary movement.
The ipsilateral primary motor cortex (M1) plays a role in voluntary movement. In our studies, we used repetitive transcranial magnetic stimulation (rTMS) to study the effects of transient disruption of the ipsilateral M1 on the performance of finger sequences in right-handed normal subjects. Stimulation of the M1 ipsilateral to the movement induced timing errors in both simple and complex sequences performed with either hand, but with complex sequences, the effects were more pronounced with the left-sided stimulation. Recent studies in both animals and humans have confirmed the traditional view that ipsilateral projections from M1 to the upper limb are mainly directed to truncal and proximal muscles, with little evidence for direct connections to distal muscles. The ipsilateral motor pathway appears to be an important mechanism for functional recovery after focal brain injury during infancy, but its role in functional recovery for older children and adults has not yet been clearly demonstrated. There is increasing evidence from studies using different methodologies such as rTMS, functional imaging and movement-related cortical potentials, that M1 is involved in ipsilateral hand movements, with greater involvement in more complex tasks and the left hemisphere playing a greater role than the right.
Adult↗
The essential tryptophan residues of pig kidney aminoacylase.
The tryptophan residues in pig kidney aminoacylase (N-acylamino acid amido hydrolase, EC 3.5.1.14) have been modified by N-bromosuccinimide (NBS) at low pH. The modification of eight tryptophan residues as measured by spectrophotometric and spectrofluorimetric methods leads to complete loss of enzymatic activity. The decreases in absorption at 280 nm and fluorescence emission at 337 nm indicate the modification of tryptophan residues. Both the inactivation and tryptophan residual modification are monophasic, first-order reactions. Quantitative treatment of the data (Tsou, C. L., Sci. Sin., 1962, 11, 1535-1558) shows that among the tryptophan residues modified, two are essential for aminoacylase catalytic activity. Kördel and Schneider (Hoppe-Seyler's Physiol. Chem. 1976, 357, 1109-1115) reported that the modification of tryptophan residues led to inactivation of aminoacylase, and suggested that tryptophan residues are essential for enzymatic activity. We have now shown that eight tryptophan residues can be modified by N-bromosuccinimide and that two of them are essential for the catalytic activity of this enzyme.
Amidohydrolases↗
Stimulation over the human supplementary motor area interferes with the organization of future elements in complex motor sequences.
We used high-frequency repetitive transcranial magnetic stimulation (rTMS) to study the role of the mesial frontocentral cortex (including the supplementary motor area) in the organization of sequential finger movements of different complexity in humans. In 15 subjects, rTMS was randomly applied to the scalp overlying the region of the supplementary motor area and over other positions, including the contralateral primary motor cortex (hand area) during the performance of three overlearned finger sequences on an electronic piano. In all trials, rTMS (frequency 15-20 Hz) started 2 s after the first key press and lasted for approximately 2 s. All sequences were metronome-paced at 2 Hz and retrieved from memory. The 'simple' sequence consisted of 16 repeated index finger key presses, the 'scale' sequence of four times four sequential key presses of the little, ring, middle and index fingers, and the 'complex' sequence of a much less systematic and, therefore, more difficult series of 16 key presses. To measure the effects of rTMS interference with regional cortical function, we analysed rTMS-induced accuracy errors in the movement sequences. Stimulation over the supplementary motor area induced accuracy errors only in the complex sequence, while stimulation over the primary motor cortex induced errors in both the complex and scale sequences, and stimulation over other positions (e.g. F3, F4, FCz, P3, P4) did not interfere with sequence performance at all. Stimulation over the supplementary motor area interfered with the organization of subsequent elements in the complex sequence of movements, with error induction occurring approximately 1 s later than with stimulation over the primary motor cortex. Our findings are in keeping with recent results in non-human primates (Tanji J, Shima K. Nature, 1994; 371: 413-6) indicating a critical role of the supplementary motor area in the organization of forthcoming movements in complex motor sequences that are rehearsed from memory and fit into a precise timing plan.
Adult↗
Indications for measles-mumps-rubella vaccination in a child with prior thrombocytopenia purpura.
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Antibodies, Viral↗
Risk of hospitalization because of aseptic meningitis after measles-mumps-rubella vaccination in one- to two-year-old children: an analysis of the Vaccine Safety Datalink (VSD) Project.
OBJECTIVE: To assess the level of increased risk, if any, of hospitalizations for aseptic meningitis after Jeryl-Lynn mumps strain measles-mumps-rubella (MMR) vaccine in the Vaccine Safety Datalink population. STUDY DESIGN: A possible increased risk of aseptic meningitis 8 to 14 days after receipt of MMR was observed in a preliminary screening analysis of automated data from the Vaccine Safety Datalink (VSD) project Year 2 analysis. To further evaluate this association a retrospective 10-year matched case-control study was undertaken in the four health maintenance organizations (HMOs) in the VSD project. Cases ascertained from a broad scan of the automated data were validated against a standard case definition. Two controls matched on age, sex, HMO and HMO membership were assigned per case. RESULTS: The VSD project involves the cooperative collection of automated vaccination and medical outcome data from four large HMOs that currently have 500,000 children younger than 7 years of age under surveillance. Review of automated screening results from the first 2 years of data revealed a possible increased risk of aseptic meningitis 0 to 14 days after MMR with a relative risk of 3.61 (95% confidence interval, 1.0 to 13.1) although the total number of cases was small. Although the automated data had suggested a possible association of aseptic meningitis with MMR containing the Jeryl-Lynn strain of mumps, review of validated hospitalized cases during the observation period did not reveal evidence of an increased risk of aseptic meningitis after MMR containing the Jeryl-Lynn strain of mumps (odds ratio < 1.0 for all analyses). CONCLUSION: Although it is recognized that hospitalized cases represent a minority of the total cases of aseptic meningitis, it is reassuring that in this evaluation no increased risk of aseptic meningitis after MMR vaccine was found.
Case-Control Studies↗
Glucose-stimulated genes and prospects of gene therapy for type I diabetes.
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Animals↗
Depression of motor cortex excitability by low-frequency transcranial magnetic stimulation.
We studied the effects of low-frequency transcranial magnetic stimulation (TMS) on motor cortex excitability in humans. TMS at 0.1 Hz for 1 hour did not change cortical excitability. Stimulation at 0.9 Hz for 15 minutes (810 pulses), similar to the parameters used to induce long-term depression (LTD) in cortical slice preparations and in vivo animal studies, led to a mean decrease in motor evoked potential (MEP) amplitude of 19.5%. The decrease in cortical excitability lasted for at least 15 minutes after the end of the 0.9 Hz stimulation. The mechanism underlying this decrease in excitability may be similar to LTD. TMS-induced reduction of cortical excitability has potential clinical applications in diseases such as epilepsy and myoclonus. Spread of excitation, which may be a warning sign for seizures, occurred in one subject and was not accompanied by increased MEP amplitude, suggesting that spread of excitation and amplitude changes are different phenomena and also indicating the need for adequate monitoring even with stimulations at low frequencies.
Adult↗
Effects of phenytoin on cortical excitability in humans.
We studied the effects of a loading dose of phenytoin on motor cortex excitability in five healthy volunteers. Phenytoin elevated motor thresholds to transcranial magnetic stimulation (TMS) in all subjects, but had no effects on motor-evoked potential amplitudes, silent period durations, and intracortical excitability tested by paired TMS during rest and voluntary muscle activation. These results are consistent with the hypothesis that blockade of voltage-gated sodium channels decreases membrane excitability and elevates the threshold to TMS, but will not reduce intracortical excitability.
Adult↗
Impaired inhibition in writer's cramp during voluntary muscle activation.
We used paired transcranial magnetic stimulation (TMS) to evaluate inhibitory mechanisms in eight patients with writer's cramp during rest and isometric wrist extension. Both stimuli were 110% of the motor threshold; the interstimulus intervals (ISIs) were 20 to 200 ms in increments of 10 ms. Surface EMG was recorded from wrist extensors. In the symptomatic hemisphere, there was no significant difference in the amplitude of the test (second) motor evoked-potential (MEP) between patients and age-matched controls at rest. However, with voluntary muscle activation, inhibition of the test MEP by the conditioning MEP was significantly less in writer's cramp patients than in controls (p = 0.02). The difference was most prominent at ISIs of 60 to 80 ms in which inhibition is maximum. In the asymptomatic hemisphere, there was no significant difference between patients and controls in both rest and active conditions. The silent period was shorter in patients than controls on the symptomatic side (p = 0.003) but not on the asymptomatic side. We conclude that the inhibitory effects induced by magnetic stimulation are reduced in patients with writer's cramp, but only on the symptomatic side during muscle activation. This may relate to the overflow of muscle activity that characterizes this condition.
Adult↗
MMR2 immunization at 4 to 5 years and 10 to 12 years of age: a comparison of adverse clinical events after immunization in the Vaccine Safety Datalink project. The Vaccine Safety Datalink Team.
BACKGROUND: The Advisory Committee on Immunization Practices recommends a second dose of measles, mumps, and rubella vaccine (MMR2) at age 4 to 5 years of age, whereas the American Academy of Pediatrics suggests MMR2 immunization at age 11 to 12 years of age. Because there is little information on whether the rate of adverse reactions to MMR2 immunization varies among these two age groups, we took advantage of differing immunization policies at two large HMOs to compare the frequency of clinical events after, and possibly related to, MMR2 immunization. METHODS: Information was collected on clinical events plausibly associated to MMR immunization (seizures, pyrexia, malaise/fatigue, nervous/musculoskeletal symptoms, rash, edema, induration/ecchymoses, lymphadenopathy, thrombocytopenia, aseptic meningitis, and joint pain) in two cohorts. At three facilities at Northern California Kaiser (Oakland, CA), 8514 children received MMR2 immunization at age 4 to 6 years of age; at Group Health Cooperative (Seattle, WA) 18 036 children received MMR2 immunization at age 10 to 12 years of age. To account for age-related differences in health care use, within each HMO, clinical events in a 30-day period after immunization were compared with a 30-day period before vaccination. RESULTS: Children 10 to 12 years of age were 50% more likely to have a clinical event after MMR2 immunization than in the period before immunization (odds ratio, 1.45; 95% confidence interval: 1.00,2.10). Children 4 to 6 years of age were less likely to have a visit for an event after immunization compared with the period before immunization (odds ratio, 0.64; 95% confidence interval: 0.40,1.01). CONCLUSIONS: These results suggest that the risk for clinical events after MMR2 immunizations is greater in the 10- to 12-year age group.
Adolescent↗
Immunization tracking systems: experience of the CDC Vaccine Safety Datalink sites.
Recognizing the potential of large databases within HMOs for the evaluation of vaccine safety, the Centers for Disease Control and Prevention (CDC) funded the Vaccine Safety Datalink project, linking outcome and vaccine exposure information at Group Health Cooperative of Puget Sound, Kaiser Permanente Northwest, Kaiser Permanente Medical Care Program Northern California, and Southern California Kaiser Permanente. Integral to the Vaccine Safety Datalink Project was the development of Immunization Tracking Systems at each site; this report describes the effort required to establish these tracking systems. Essential requirements are the methods used to insure data quality and to educate system users. Tracking systems can be a valuable means for assessing vaccine coverage, evaluating barriers to complete immunization, and studying the effectiveness of interventions design to improve immunization coverage. Finally, we report on recent efforts to link HMO Immunization Tracking Systems with developing regional tracking systems.
California↗
[10-year epidemiological study on rheumatic diseases in Shantou area].
22,049 adults were surveyed in a ten-year epidemiological study. The frequency of common rheumatic symptoms in Shantou population was much lower than that in northern China. The prevalence of ankylosing spondylitis, rheumatoid arthritis, osteoarthritis, osteoporosis and gout was 0.20%-0.32%, 0.20%-0.26%, 8.3%-10.8%, 12.4% and 0.15%-0.17% respectively. The frequency of HLA-B27 was 4.1% among general population and 90.6% in ankylosing spondylitis. The most commonly involved sites of osteoarthritis were lumbar spine, neck, and knee; but hands and hip were rarely involved. 85% subjects under investigation were found to be short of calcium intake. The differences between the north and the south of China in the prevalence of rheumatic symptoms may be related to the diversities in consciousness of seeking medical advice, reduction of bone content, climate and ergonomics.
Adult↗
Treatment of apoplectic hemiplegia by digital acupoint pressure--a report of 42 cases.
Forty-two cases of apoplectic hemiplegia treated by digital acupoint pressure (DAP) therapy are briefly reported in this paper. This results were: basic cure in 10 cases (23.8%), marked effect in 17 cases (40.5%) and effect in 11 cases (26.2%). The total effective rate reached 90.5%. This therapy has several advantages, such as simple and convenient operation, low cost, reliable results and so on.
Acupressure↗