Biomedical subjects

Shunwei Li

Publications and source records attributed to Shunwei Li.

8 recordsLinked to original sources

PubMed2005

Distinctive conflict processes associated with different stimulus presentation patterns: an event-related potential study.

Twelve subjects were asked to perform visual stimulus presentation tasks. Two figures were presented either simultaneously or sequentially. They were either in congruity (same shapes) or in conflict (different shapes) with each other. Conflicting stimulus pairs presented sequentially evoked a negative event-related component with a fronto-central and bilateral posterior scalp distribution, referred to as N270. In contrast, stimuli displayed simultaneously elicited a N220 with fronto-central prominence, irrespective of whether they were in conflict or in congruity. The results suggest that the N270 may be associated with the processing of a conflict with working memory information whereas the N220 might reflect the detection and evaluation of attention to visual information in the human brain.

Adult↗

PubMed2005

Respiratory complaints in Chinese: cultural and diagnostic specificities.

STUDY OBJECTIVES: We investigated the qualitative components of a wide range of Chinese descriptors of dyspnea and associated symptoms, and their relevance for clinical diagnosis. MEASUREMENTS: Sixty-one spontaneously reported descriptors were elicited in Chinese patients to make a symptom checklist, which was administered to new groups of patients with different cardiopulmonary diseases, to patients with medically unexplained dyspnea and to healthy subjects. RESULTS: Test-retest reliability was satisfactory for most of the descriptors. A principal component analysis on 61 descriptors yielded the following eight factors: dyspnea-effort of breathing; dyspnea-affective aspect; wheezing; anxiety; tingling; palpitation; coughing and sputum; and dying experience. Although the descriptors of dyspnea-effort of breathing resembled Western wordings and were shared by patients with a variety of diseases, the descriptors of dyspnea-affective aspect appeared to be more culturally specific and were primarily linked to the diagnosis of medically unexplained dyspnea, whereas wheezing was specifically linked to asthma. CONCLUSIONS: Three factors of breathlessness were found in Chinese. The descriptors of dyspnea-effort of breathing and wheezing appear to be similar to Western descriptors, whereas the dyspnea-affective aspect seems to bear cultural specificity.

Adolescent↗

PubMed2004

Assessment of the therapeutic activity of a combination of almitrine and raubasine on functional rehabilitation following ischaemic stroke.

BACKGROUND AND OBJECTIVES: Stroke is a major cause of disability. Certain experimental studies have suggested that a combination of almitrine + raubasine (Duxil) increases the supply of oxygen to cerebral tissues and may be beneficial in post-stroke rehabilitation. This multicentre clinical study was carried out in order to assess the efficacy of this combination on poststroke rehabilitation. METHODS: The trial was a randomised, double-blind, placebo-controlled study. Patients that had experienced an ischaemic cerebrovascular accident (confirmed by CT scan) were included 4-6 weeks after the acute onset and received randomised treatment of either almitrine + raubasine or placebo 2 tablets daily for 3 months. Before treatment, there was a 2-week washout period for stopping all other drugs, except for antihypertensive and antidiabetic drugs. We assessed the patients by Barthel Index (BI), Neurological Functional Deficit Scores (NFDS), and Hasagawa Dementia Scales (HDS) each month after treatment. RESULTS: A total of 83 patients were entered into the study and data were available for 74. Of these, 38 patients received almitrine + raubasine and 36 received placebo. The baseline characteristics were comparable between both groups. Almitrine + raubasine was significantly more effective than placebo at increasing BI at 1, 2 or 3 months (14.6 +/- 13.8 versus 3.3 +/- 13.2, p = 0.01; 19.3 +/- 13.6 versus 8.8 +/- 14.0, p = 0.02; 22.6 +/- 14.7 versus 10.7 +/- 17.0, p = 0.02 respectively) and reducing NFDS at 1 month (3.6 +/- 3.2 versus 1.9 +/- 3.5, p = 0.034) after treatment. More almitrine + raubasine-treated patients' NFDS had improved compared with placebo-treated patients at 2 and 3 months (97 versus 78%, p = 0.013; 100 versus 86%, p = 0.023 respectively). Compared with pretreatment, there was a strong tendency towards an improvement of HDS with almitrine + raubasine. The number of adverse events reported was low for the almitrine + raubasine-treated group and the placebo group and all events were mild, of short duration and resolved without treatment. Almitrine + raubasine had no clinically significant effect on blood pressure, heart rate or other laboratory tests. CONCLUSION: The results indicate that almitrine + raubasine can accelerate neurological function recovery after stroke to some degree and is well tolerated.

Aged↗

PubMed2003

Event-related potential N270, a negative component to identification of conflicting information following memory retrieval.

OBJECTIVE: N270, an endogenous ERP component of conflict effect, was evoked in previous studies with S1-S2 paradigm. The present experiment is designed to confirm the speculation that this conflict-related negativity could also be elicited by stimulus probes having conflict with a memorized item in a visual post-retrieval comparison task. METHODS: A Sternberg probe-matching paradigm was modified in the present study. The stimuli consisted of a memory set of 3 different items (simple figures) and a retrieval set of 3 probe figures. Subjects matched each probe to its corresponding item in the memory set. The tasks were designed with different conflict loads of no-conflict, low-conflict and high-conflict in the probe retrieval test. RESULTS: Probes of no-conflict elicited a major positive going component, P300, with bilateral parietal distribution. Probes of low- and high-conflict evoked N270, while N430 was elicited only in high-conflict condition. N270 was more negative in high-conflict condition than in low-conflict condition. The N270 was right hemispheric prominent in the low-conflict task and remarkably distributed over the right prefrontal areas. On the other hand, both N270 and N430 were distributed bilaterally on the scalp in the high-conflict task. CONCLUSIONS: The present results demonstrate that the N270 is an index to the conflict identification, while the N430 of the high-conflict task reflects the processing for complex conflicts following probe retrieval. These negativities are related to the processing of conflicts.

Adult↗

PubMed2002

[Neurology].

Explore the source record for details and available documents.

Alzheimer Disease↗

PubMed2002

[Insulin-like growth factor-I and cognitive function in patients with obstructive sleep apnea syndrome].

OBJECTIVE: To explore the possible biochemical mechanism of cognitive impairment in patients with obstructive sleep apnea syndrome (OSAS). METHODS: Polysomnography was administered to thirty-six patients with OSAS and eighteen education and BMI-matched controls, all males aged 40 approximately 49 for 8.5 hours at night. Early next morning blood was drawn and serum insulin-like growth factor-I (IGF-I) was determined by immunoradiometric assay. Then neuropsychological tests of visual regeneration, digital symbol, comprehensive memory and digital span were conducted. RESULTS: The quality of sleep in the patients with OSAS was significantly worse than that of the controls. The score of visual regeneration in the patients with OSAS was 8.4 +/- 2.7, significantly lower than that in control group (11.6 +/- 1.4, P < 0.01). The score of digital symbol in patients with OSAS was 36.92 +/- 8.31, significantly lower than that in the controls (47.8 +/- 6.8, P < 0.01). The serum IGF-I level of the patients with OSAS was: 127.2 +/- 87.0 ng/ml, significantly lower than that of the controls (194.03 ng/ml +/- 77.31 ng/ml, P < 0.05). The IGF-I level was significantly positively correlated with the scores of visual regeneration test (r = 0.381, P < 0.05) and digital symbol test (r = 0.330, P < 0.05), lowest SaO(2) (r = 0.371, P < 0.05), mean SaO(2) (r = 0.333, P < 0.05) and REM sleep duration (r = 0.598, P < 0.01). CONCLUSION: Decrease of serum IGF-I level may play a role in the cognitive impairment in patients with OSAS. Nocturnal hypoxemia and REM sleep deprivation may be the reason of the decrease of the serum IGF-I level in patients with OSAS.

Adult↗

PubMed2002

Early detection of cognitive impairment in patients with obstructive sleep apnea syndrome: an event-related potential study.

Event-related potentials (ERPs) were recorded to visual stimuli in a task that required matching the shape and serial position of the probes against previously memorized items. The effects of hypoxia on ERP were investigated in 24 patients with obstructive sleep apnea syndrome (OSAS) and a matched control group. N2b-late positive-going (LPC) components were elicited by probes that identically matched the memorized items (no-conflict condition). In contrast, N270-LPC and N270-N430-LPC components were elicited by probes having low-conflict and high-conflict with the memory set. Conflict ERP effect decreased in mild, while both no-conflict and conflict ERP effects decreased in amplitude in severe OSAS patients. Conflict ERPs associated with processing of conflicting information are more vulnerable than no-conflict ERPs to hypoxic cerebral damage.

Adult↗

PubMed2002

[Hyperhomocysteine, methylenetetrahydrofolate reductase gene, and other risk factors in ischemic stroke].

OBJECTIVE: To investigate the relation between plasma homocysteine (Hcy) and cerebral ischemic diseases and that between polymorphism of methylenetetrahydrofolate reductase (MTHFR) gene and cerebral ischemic diseases. METHODS: The plasma homocysteine (Hcy) and genetic polymorphism of MTHFR among forty-nine cases with ischemic cerebral diseases, including 25 with acute cerebral infarction (CI) and 25 with transient ischemic attacks (TIA), were investigated. Fifty-five age- and sex-matched healthy persons were used as controls. All the subjects underwent brain CT, carotid duplex, transcranial Doppler examination, plasma Vitamin B(12) and folic acid examination, besides examination of plasma Hcy and nucleotide 677 MTHFR genotypes. The effects of age, liver function, renal function, smoking, drinking, plasma vitamin B(12), and folic acid were analyzed. RESULTS: The mean plasma Hcy was significantly higher in the CI group and TIA group (17.4 +/- 7.6 micromol/L and 16.6 +/- 5.2 micromol/L) compared with that in the control group (12.6 +/- 5.2 micromol/L, P < 0.01). The odds ratio was 3.26 (95% CI, 1.05 approximately 10.09, P < 0.01). The Hcy concentration was significantly higher in persons with T/T genotype than in those with C/C or CT. There was no significant difference of frequency of mutant alleles (T) in site 677 of MTHFR gene and in frequency of homozygote T/T among the patients and controls (52.0% vs. 44.0%, P < 0.05 and 26% vs. 20.0%, P > 0.05). The difference of Hcy was significant between those being T/T homozygotic and those not being T/T homozygotic in different groups. There was no statistical correlation between plasma Hcy level and extra- and intracranial stenosis of cerebral artery. Increase of BUN and smoking were significantly correlated with increase of Hcy (P < 0.05). The concentrations of plasma Vitamin B(12) and folic acid were significantly correlated with that of Hcy. CONCLUSION: Homozygote of mutant MTHFR gene C677T causes hyperhomocystinemia. There is a significantly association between hyperhomocystinemia and ischemic cerebrovascular disease. The frequency of mutation in MTHFR genotype is higher in Chinese than in Caucasians. In addition to gene mutation, renal function and smoking are related to increase of plasma Hcy. No correlation between genotype of MTHFR and stroke is found.

Asian People↗