Biomedical subjects

Yao-Chung Chuang

Publications and source records attributed to Yao-Chung Chuang.

At least 19 recordsLinked to original sources

PubMed2006

Effects of rosiglitazone on global ischemia-induced hippocampal injury and expression of mitochondrial uncoupling protein 2.

We investigate the effect of rosiglitazone, a ligand for peroxisome proliferator-activated receptor-gamma (PPARgamma) with anti-inflammatory and anti-oxidative actions, on hippocampal injury and its roles in mitochondrial uncoupling protein 2 (UCP2) expression caused by transient global ischemia (TGI) in rats. Increased UCP2 expression was observed in mitochondria of hippocampal CA1 2-24h after TGI/reperfusion, with maximal expression levels at 6-18h. Administration of rosiglitazone to hippocampus 30min prior to the onset of TGI further enhanced mitochondrial UCP2 expression 2-6h following TGI/reperfusion. Rats subjected to TGI/reperfusion displayed a significant increase in lipid peroxidation, based on increased malondialdehyde (MDA) levels, in hippocampal CA1 mitochondria 2-6 h after reperfusion. Rosiglitazone significantly attenuated TGI/reperfusion-induced lipid peroxidation and suppressed hippocampal CA1 neuronal death based on the surviving neuronal counts. In conclusion, our results provide correlative evidence for the "PPARgamma-->UCP2-->neuroprotection" cascade in ischemic brain injury.

Animals↗

PubMed2006

A common mitochondrial DNA variant and increased body mass index as associated factors for development of type 2 diabetes: Additive effects of genetic and environmental factors.

OBJECTIVE: The suggested correlation between a T-to-C transition at the nucleotide 16189 in mitochondrial DNA (mtDNA) with increasing insulin resistance and adult-onset diabetes mellitus (DM) is debatable. METHODS: Our study examined mtDNA from 462 subjects with type 2 diabetes (T2DM) and 592 normoglycemic controls (non-DM). Each participant's body mass index (BMI), fasting plasma glucose, fasting insulin concentration, insulin resistance index, and beta-cell function were measured. Sequencing for mtDNA, focusing on exploration of the hypervariable polycytosine tract within the control region, was also conducted in all subjects. RESULTS: Prevalence of the mtDNA 16189 variant was significantly different between DM and non-DM subjects (39.2% vs. 30.7% respectively; P = 0.004). Increased incidence of DM was noted in those harboring the 16189 variant compared with those lacking the variant (multivariate odds ratio, 1.38; 95% confidence interval, 1.07-1.80). Moreover, increased BMI was identified as an aggravating factor for development of DM in subjects harboring the variant. Odds ratio determinations yielded 2.14 in overweight and 4.63 in obese subjects harboring the variant in comparison with subjects without (1.83 in overweight and 2.16 in obese subjects). This is consistent with a progressively increased prevalence of the mtDNA 16189 variant in the non-DM groups with higher fasting insulin concentration, insulin resistance index, and beta-cell function (all P(trend) < 0.005). CONCLUSION: The mtDNA 16189 variant can influence development of T2DM. The demonstrated dynamic between the 16189 variant and increased BMI exemplify an additive effect of genetic and environmental factors on the pathogenesis of T2DM.

Adult↗

PubMed2006

Game-related seizures presenting with two types of clinical features.

We evaluated 22 patients with epileptic seizures in which the seizures were triggered by various games or game-related materials. Based on whether spontaneous seizure coexisted or not, these 22 patients were divided into two groups. Ten patients who experienced seizures exclusively while playing or watching specific games were referred to as Group I, while 12 patients that had both game-induced and spontaneous seizures were classified as Group II. The patients in Group I had a middle-age onset (39.1 years) with a male predominance (90%). The electroencephalogram (EEG) or brain magnetic resonance imaging revealed non-specific abnormalities in 60%, and the partial onset seizure was recognized in 30% of patients. Antiepileptic drugs had uncertain benefits in this group. In Group II, patients had a male predominance (67%), with onset during adolescence (16.3 years). Most of them had generalized tonic-clonic seizures, myoclonic seizures, and absences, and 42% showed epileptiform discharge on EEG. These 12 patients were categorized into idiopathic generalized epilepsies. Although photosensitivity was an important factor, higher mental activity seemed to be significant precipitants of seizures in Group II. Antiepileptic drugs were necessary and valproic acid alone or combined with clonazepam was effective in this group. The results showed that game-related seizures are not a unique and homogeneous syndrome and may consist of different mechanisms. Teenage onset, coexistent spontaneous seizure, and associated idiopathic generalized epilepsies were crucial factors in the determination of antiepileptic drug therapy. Moreover, avoiding the related games altogether may be a more productive preventive measure.

Adolescent↗

PubMed2006

Massively multiplayer online role-playing game-induced seizures: a neglected health problem in Internet addiction.

As the Internet has become rapidly and widely integrated into society, Internet addiction has become a growing psychosocial problem. However, epileptic seizure, another out-of-the-ordinary health problem, is often neglected in this regard. Ten patients who experienced epileptic seizures while playing the newest genre of electronic games -- Massively Multiplayer Online Role-Playing Games (MMORPGs) -- were investigated. Patients were predominantly male young adults, and most of the events were generalized tonic-clonic seizures, myoclonic seizures, and absences. These patients should be categorized into idiopathic generalized epilepsies. Even though photosensitivity was an important factor, behavioral and higher mental activities also seemed to be significant seizure precipitants. Results demonstrated that MMORPG-induced seizures were not analogous to the ordinary video game-induced seizures. Significantly, an epileptic seizure warning did not always appear on the websites of MMORPGs and instructions for the software. While the prevalence of MMORPG-induced seizures remains unknown, it may exceed our expectations and impact our society. Not only for clinical neurologists but also for the primary physicians, educators, sociologists, and global online game publishers, there should be an awareness of this special form of reflex seizures in order to provide an appropriate health warning to MMORPG players.

Adolescent↗

PubMed2006

Culture-proven bacterial meningitis in elderly patients in southern Taiwan: clinical characteristics and prognostic factors.

The epidemiologic landscape of causative pathogens and clinical characteristics of bacterial meningitis varies with several clinical factors including preceding/pre-existent medical and/or surgical conditions, modes of contraction, geographic distributions, status of vaccinations, the study time periods and differences among age groups. In order to delineate the epidemiology of bacterial meningitis in senior adults (ages > or =60 y/o) in southern Taiwan, we analyzed the clinical characteristics and therapeutic outcomes of 64 senior adults (42 men and 22 women, aged 60-80 years) with bacterial meningitis collected over a period of 13 years at our hospital. The prognostic factors between fatal and non-fatal groups of patients were compared. Twenty-seven of the 64 patients belonged to a nosocomial infection group, and the other 37 comprised a community-acquired infection group. Sixty percent (39/64) of the patients had a post-neurosurgical state as the most preceding event prior to infection. Liver disease (13) and diabetes mellitus (6) were the most common underlying conditions of the other 25 patients with spontaneous meningitis. Of these 64 patients, Klebsiella (K.) pneumoniae (18), Acinetobacter baumannii (5), Escherichia coli (5), and Enterobacter species (5) were the most commonly implicated Gram-negative pathogens. Staphylococcus (S.) aureus infection was increasing during the study period. The therapeutic results of this group of patients showed a mortality rate of 38% (24/64). The presence of septic shock was the most significant prognostic factor. In conclusion, for this study group, a post-neurosurgical state was the single most important preceding event for senior adults developing bacterial meningitis. Of the implicated pathogens, K. pneumoniae and S. aureus were the most common gram-negative and gram-positive pathogens, respectively. The therapeutic result of this specific group of patients showed a high mortality rate; however, the small case number and possible bias of case selection have limited the analytical conclusions of this study.

Aged↗

PubMed2006

Exercise test in the inter-attack period of thyrotoxic periodic paralysis: a useful diagnostic tool.

Exercise test was reported to be useful for some patients with periodic paralysis. We report here the results of exercise test in three cases of thyrotoxic periodic paralysis, for whom the exercise test was all positive. Exercise test could be one of the diagnostic tools in the "inter-attack" state of the probable cases with thyrotoxic periodic paralysis. However, the case number of this study is small and larger-scale studies may be warranted in the future.

Action Potentials↗

PubMed2005

The significance of seizures and other predictive factors during the acute illness for the long-term outcome after bacterial meningitis.

BACKGROUND: Seizures are important neurological complications of bacterial meningitis, but no information about its epidemiology and the outcomes of seizures after community-acquired bacterial meningitis (CABM) in an adult population have been reported. AIMS: To determine the frequency, clinical relevance, subtypes of seizures during the acute phase of bacterial meningitis, and the long-term outcomes of seizure complicating adult CABM. METHODS: In this 12-year retrospective study, 117 adult patients were identified with culture-proven CABM. A comparison was made between the clinical data of the patients with and without seizures during hospitalization. RESULTS: Thirty-one patients had seizures during CABM, accounting for 27% (31/117) of the episodes. The time interval between the onset of bacterial meningitis and the seizures was 1-21 days (mean, 4 days). Furthermore, 80% (25/31) of the episodes occurred within 24 h of presentation. Ten patients who had seizures progressed to status epilepticus. At follow-up after completing treatment, 10 patients completely recovered and were seizure-free, 19 died of meningitis during the acute stage and the other two progressed to chronic epilepsy. CONCLUSION: A log-rank test demonstrated that the long-term outcome of adult CABM with acute seizures produced worse outcomes than for those who had no seizures, though no difference was noted between focal and generalized seizures. None of our patients without seizures in the acute phase of bacterial meningitis developed late seizures during the follow-up periods. Poor outcome in this study may attribute to neurological complications such as seizure, hydrocephalus, infection itself, or a combination of complications.

Aged↗

PubMed2005

Status epilepticus induced by star fruit intoxication in patients with chronic renal disease.

Star fruit has been reported as containing neurotoxins that often cause severe neurological complications in patients with chronic renal disease. We report two patients with chronic renal failure at a pre-dialyzed stage who developed refractory status epilepticus after ingestion of star fruit. In addition, we review 51 cases in the literature. Among 53 patients, 16 patients presented with epileptic seizures (30%). The mortality rate was as high as 75% in patients with seizures. On the other hand, in patients without seizures, the mortality rate was only 0.03%. There is a poor correlation with the degree of underlying renal function and mortality due to intoxication. We propose that epileptic seizure is significantly associated with poor prognosis, and that status epilepticus is an unpredictable and potentially fatal complication in star fruit intoxication. We advise consultant neurologists that star fruit intoxication must be considered when patients with chronic renal disease present with seizures or other unexplained neurological or psychiatric symptoms. Since no effective treatment has been established, star fruit consumption should be avoided in patients with chronic renal disease, especially in the elderly.

Aged↗

PubMed2005

Adult Streptococcus pneumoniae meningitis in Southern Taiwan: epidemiologic trends and prognostic factors.

The clinical features of 22 adult patients with Streptococcus pneumoniae meningitis, retrospectively collected over a 16-year period, were reviewed. Otopharyngeal infection, haematogenous spread and cranial neurosurgery continue to be the predominant routes of infection. Most patients acquired the infection in the community, and predisposing underlying conditions are common. The proportion of S. pneumoniae meningitis compared to all microorganisms causing meningitis in adults declined dramatically from 17% in the first 8 study years to 4% in the last 8 study years. However, all penicillin-resistant S. pneumoniae strains were found in the second half of the study period, accounting for 25% of these episodes. The overall mortality rates for the first and second halves of the study period were 43% and 63%, respectively. Third-generation cephalosporins were the antibiotics of choice for the treatment of S. pneumoniae meningitis in this study, however, the emergence of resistant strains may create a therapeutic challenge in the future. To avoid treatment failure, early diagnosis, careful monitoring of the clinical course and the choice of appropriate antibiotics according to the in vitro antimicrobial susceptibilities, are necessary.

Adolescent↗

PubMed2005

Post-neurosurgical nosocomial bacterial meningitis in adults: microbiology, clinical features, and outcomes.

The clinical data of 62 adult patients who suffered post-neurosurgical nosocomial bacterial meningitis, retrospectively collected over a 16-year period, were studied. Cases were divided into two groups based on the date of presentation, the first period being 1986-1993 and the second 1994-2001. Fever and progressive consciousness disturbance were the most consistent clinical features - signs that may also be attributed to other postoperative neurosurgical problems. The common pathogens included Staphylococcus aureus, coagulase negative Staphylococcus, Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii. An increase in polymicrobial infections and multi-antibiotic resistance during the second period was identified. In the first half of the study, mortality was 22%, and in the second half 36%. Adult post-neurosurgical nosocomial bacterial meningitis has become an important clinical problem. The choice of appropriate empirical antibiotics is challenging and must be guided by an awareness of the relative frequency of various pathogens and the increasing incidence of resistant strains. Although high mortality rates may, in part, be related to the primary brain pathology, early diagnosis and the timely use of antibiotics based on antimicrobial susceptibility testing are essential for survival.

Adolescent↗

PubMed2005

Mah-Jong-induced epilepsy: a special reflex epilepsy in Chinese society.

We present five patients of epilepsy in which seizures were triggered by playing or watching the traditional Chinese gambling game "Mah-Jong." One patient also experienced seizures while playing a computer version of the Mah-Jong game. This condition appeared to have a predominance of males (80%) and middle-aged onset (39.4 years). Four patients had generalized tonic-clonic seizures and one patient had partial seizures with secondary generalization. No spontaneous seizure occurred in these patients. Three patients had been receiving antiepileptic drug therapy, but without effective control over their seizures. Mah-Jong-induced epilepsy is a very peculiar form of complex reflex epilepsy that involves the higher mental activities. This phenomenon may consist of distinct pathophysiologic mechanisms from other reflex epilepsy induced by thinking and spatial tasks in idiopathic generalized epilepsies. This unusual reflex epilepsy is relatively benign in nature and antiepileptic drug therapy has uncertain benefits. It may be necessary to avoid playing the Mah-Jong game in order to prevent seizures.

Adult↗

PubMed2005

Increased oxidative damage with altered antioxidative status in type 2 diabetic patients harboring the 16189 T to C variant of mitochondrial DNA.

A transition of T to C at nucleotide position 16189 in mitochondrial DNA (mtDNA) has attracted biomedical researchers for its probable correlation with the development of diabetes mellitus in adult life. In diabetes, persistent hyperglycemia may cause high production of free radicals. Reactive oxygen species are thought to play a role in a variety of physiologic and pathophysiologic processes in which increased oxidative stress may play an important role in disease mechanisms. The aim of the present study was to clarify the degree of oxidative damage and plasma antioxidant status in diabetic patients and to see the potential influence of the 16189 variant of mtDNA on the oxidative status in these patients. An indicative parameter of lipid peroxidation, malondialdehyde (MDA), and total free thiols were measured from plasma samples of 165 type 2 diabetic patients with or without this variant and 168 normal subjects. Here we report an increase in the plasma levels of MDA and total thiols in type 2 diabetic patients compared with control subjects. The levels of plasma thiols in diabetic patients with the 16189 variant of mtDNA were not different from those in controls. These results suggest an increase in the oxidative damage and a compensatory higher antioxidative status in patients with type 2 diabetes. Harboring the 16189 mtDNA variant may impair the ability of a cell to respond properly to oxidative stress and oxidative damage.

Antioxidants↗

PubMed2005

Adult Acinetobacter meningitis and its comparison with non-Acinetobacter gram-negative bacterial meningitis.

Between January 1999 and December 2003, 81 cases of single pathogen-related culture-proven Gram-negative adult bacterial meningitis were identified at Chang Gung Memorial Hospital-Kaohsiung. Of these 81 cases, Acinetobacter infection was found in 13 cases. Clinical and laboratory data of these Acinetobacter meningitis patients were studied and were compared with those of other 68 non-Acinetobacter Gram-negative bacterial meningitis (GNBM) patients. Of the 13 implicated Acinetobacter strains, A. baumannii was the most common (12), and the other was A. lwoffii (1). Eleven of these 13 cases were due to a post-neurosurgical infection. The results of the antibiotic susceptibility test of the 13 Acinetobacter strains from cerebrospinal fluid included ceftriaxone, (1/13, 8%), ciprofloaxin (6/13, 46%), ceftazidime (6/13, 46%), cefepime (7/13, 54%), ampicillin-subtactam (7/13, 54%), imipenem (12/13, 92%) and meropenem (12/13, 92%). One strain with pan-drug resistant A. baumannii (PDRAB) emerged in 2003. A statistically significant difference between Acinetobacter meningitis and non-Acinetobacter GNBM included hydrocephalus and ceftazidime-resistance. A mortality rate was 30% (4/13), and 7 of the other 9 survivals had severe neurologic deficits. The emergence of Acinetobacter infections in adult post-neurosurgical infections, multiple antibiotic resistant characteristics, and the emergence of PDRAB strain remained a challenge of the initial management of this specific meningitis. Use of carbapenem, especially meropenem, could be considered as one of the initial empiric antibiotics chosen for the management of adult post-neurosurgical meningitis.

Acinetobacter Infections↗

PubMed2004

Association of the mitochondrial DNA 16189 T to C variant with lacunar cerebral infarction: evidence from a hospital-based case-control study.

A transition of T to C at nucleotide position 16189 in the hypervariable D-loop region of mitochondrial DNA (mtDNA) has attracted research interest for its probable correlation with increasing insulin resistance and development of diabetes mellitus (DM) in adult life. In this article, we present our observations of the positive relationship between this variant and cerebral infarction. Six hundred and one subjects in two groups-one with cerebral infarction (307 cases), the other with no cerebral infarction (294 cases)-were recruited. Their clinical features, fasting blood sugar and insulin levels, and insulin resistance index, were recorded. Patients with cerebral infarction were further categorized into four different subgroups according to the TOAST criteria for stroke classification. The results showed the occurrence of the mtDNA 16189 variant in 34.2% of patients with cerebral infarction and in 26.5% of normal controls. The difference in the occurrence rates between the two groups was statistically significant (P = 0.041). Further studies of the occurrence rate in each stroke subgroup revealed that the variant occurred at the highest frequency in the small vessel subgroup (41.5%). The difference in occurrence rate between this subgroup and the normal controls is highly significant (P = 0.006). These results correlated well with the findings of significantly increased levels of average fasting blood insulin and a higher index of average insulin resistance in the small vessel subgroup of patients harboring this mtDNA variant. Taken together, we suggest that the mtDNA 16189 variant is a predisposing genetic factor for the development of insulin resistance and may be related to various phenotypic expressions in adult life such as development of DM and vascular pathologies involved in stroke and cardiovascular diseases.

Adult↗

PubMed2004

Seizures complicating infantile and childhood bacterial meningitis.

In this study, 116 patients, at least 1 month of age but younger than 5 years, were identified with culture-proven bacterial meningitis. A comparison was made between the clinical data of the patients with and without seizures during hospitalization. Seizures during acute bacterial meningitis accounted for 47% (55/116) of the episodes. Time interval between the onset of bacterial meningitis and that of seizures was 1 to 20 days (mean, 4 days). Twelve of these 55 patients had one or more afebrile seizures after completing the treatment. At follow-up of at least 1 year after completing treatment, 26 patients had good outcomes, whereas the other 29 patients had poor outcomes. A strong correlation between the findings of abnormalities through neuroimaging and the occurrence of seizures during hospitalization was observed. The long-term outcomes of patients with infantile and childhood bacterial meningitis, who had seizures during the acute phase of bacterial meningitis, were worse than the outcomes of those who did not have such seizures. No child developed late seizures unless there were acute seizures. Factors associated with seizures during acute bacterial meningitis include disturbed consciousness on admission, abnormal neuroimaging findings, and low glucose and high concentration of total proteins in cerebrospinal fluid.

Chi-Square Distribution↗

PubMed2004

Tooth-brushing epilepsy with ictal orgasms.

We report a 41-year-old woman with complex reflex epilepsy in which seizures were induced exclusively by the act of tooth brushing. All the attacks occurred with a specific sensation of sexual arousal and orgasm-like euphoria that were followed by a period of impairment of consciousness. Ictal EEG demonstrated two events of epileptic seizure that were provoked after tooth brushing for 38 and 14 seconds, respectively. The interictal EEG showed epileptiform discharges over the right anterior temporal region and interictal single photon emission computed tomography (SPECT) scan showed relative hypoperfusion in the uncus of right temporal lobe. Brain magnetic resonance imaging (MRI) revealed right hippocampal atrophy. We suggest that tooth-brushing epilepsy, especially with sexual ictal manifestations, may provide insight into the cerebral pathophysiology at the right temporolimbic structure.

Adult↗

PubMed2004

Mitochondrial dysfunction and ultrastructural damage in the hippocampus during kainic acid-induced status epilepticus in the rat.

PURPOSE: Prolonged and continuous epileptic seizure (status epilepticus) results in cellular changes that lead to neuronal damage. We investigated whether these cellular changes entail mitochondrial dysfunction and ultrastructural damage in the hippocampus, by using a kainic acid (KA)-induced experimental status epilepticus model. METHODS: In Sprague-Dawley rats maintained under chloral hydrate anesthesia, KA (0.5 nmol) was microinjected unilaterally into the CA3 subfield of the hippocampus to induce seizure-like hippocampal EEG activity. The activity of key mitochondrial respiratory chain enzymes in the dentate gyrus (DG), or CA1 or CA3 subfield of the hippocampus was measured 30 or 180 min after application of KA. Ultrastructure of mitochondria in those three hippocampal subfields during KA-induced status epilepticus also was examined with electron microscopy. RESULTS: Microinjection of KA into the CA3 subfield of the hippocampus elicited progressive build-up of seizure-like hippocampal EEG activity. Enzyme assay revealed significant depression of the activity of nicotinamide adenine dinucleotide cytochrome c reductase (marker for Complexes I+III) in the DG, or CA1 or CA3 subfields 180 min after KA-elicited temporal lobe status epilepticus. Conversely, the activities of succinate cytochrome c reductase (marker for Complexes II+III) and cytochrome c oxidase (marker for Complex IV) remained unaltered. Discernible mitochondrial ultrastructural damage, varying from swelling to disruption of membrane integrity, also was observed in the hippocampus 180 min after hippocampal application of KA. CONCLUSIONS: Our results demonstrated that dysfunction of Complex I respiratory chain enzyme and mitochondrial ultrastructural damage in the hippocampus are associated with prolonged seizure during experimental temporal lobe status epilepticus.

Animals↗

PubMed2004

Infection of cerebrospinal fluid shunts: causative pathogens, clinical features, and outcomes.

This retrospective chart review describes the clinical features, pathogens, and outcomes of 46 patients with cerebrospinal fluid (CSF) shunt infections collected over 16 years. The overall CSF shunt infection rate was 2.1%, broken down into 1.7 and 9.3% in adult and pediatric groups, respectively. Fever and progressive consciousness disturbance were the most clinical features in the adult patient group, whereas disturbance of consciousness and abdominal symptoms and signs were the two most common clinical features in the pediatric patient group. The most frequently isolated microorganisms were of the Staphylococcus spp., including Staphylococcus aureus and coagulase negative Staphylococcus, which accounted for 47% of the episodes. Furthermore, increases in polymicrobial and Gram-negative bacilli infections were observed in our study. Due to the high proportion of oxacillin-resistant Staphylococcus spp. and polymicrobial infections, we recommend initial empirical antibiotics with both vancomycin and a third-generation cephalosporin for cases in which the causative bacteria has not been identified or for which the results of antimicrobial susceptibility tests are not available. For patients who develop smoldering fevers, progressive disturbed consciousness, seizures, or abdominal fullness after ventriculoperitoneal shunt procedures, CSF shunt infections should be suspected. Although some infections have been managed successfully with antimicrobial therapy alone, the timely use of appropriate antibiotics according to antimicrobial susceptibility testing and the removal of the shunt apparatus are essential for successful treatment.

Adolescent↗