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Biomedical subjects

R T Lin

Publications and source records attributed to R T Lin.

At least 19 recordsLinked to original sources
PubMed2006

Emergence of community-associated methicillin-resistant Staphylococcus aureus in Singapore: a further six cases.

INTRODUCTION: The clinical features and molecular epidemiology of further cases of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection in Singapore are described. METHODS: Six cases of CA-MRSA infection that occurred between April and October 2004 are described. The bacterial isolates were tested for the presence of Panton-Valentine leukocidin (PVL) genes and typed via pulsedfield gel electrophoresis, staphylococcal chromosomal cassette mec (SCCmec) and multi-locus sequence typing. The results were compared with that of previously-reported local and international CA-MRSA isolates. RESULTS: There were four cases of cutaneous abscesses and one each of chronic osteomyelitis and endocarditis. CA-MRSA isolates from the last two cases tested negative for PVL genes. Three isolates were identical and related to the Oceanian clone, and one isolate to the predominant Taiwanese clone. The isolate causing osteomyelitis had a novel sequence type. CONCLUSION: CA-MRSA, though uncommon, is being isolated with increasing frequency in Singapore. A predominant clone (ST30- MRSA-IV) seems to be emerging locally.

Adult↗
PubMed2003

Apolipoprotein E in Taiwan Chinese patients with dementia.

To clarify whether Alzheimer's disease (AD) and vascular dementia (VaD) share the same risk factors in Taiwan Chinese patients. Using the criteria of the NINCDS- ADRDA and NINDS-AIREN, 154 AD patients, 30 VaD patients, and 112 controls were enrolled. Their apolipoprotein E (ApoE) genes, extracted from peripheral blood leukocytes, were analyzed. The epsilon4 allele frequency was significantly higher in AD patients than in the control group. The odds ratio of carrying at least one copy of the epsilon4 allele in AD patients is 2.7 compared with control subjects. There was no significant difference between the VaD patients and the control subjects in their ApoE epsilon4 or epsilon2 allele frequency. The present study demonstrates a strong association between the ApoE epsilon4 allele and AD, but not between the ApoE epsilon4 allele and VaD. This suggests that AD and VaD do not share the same pathogenesis and deserve further investigation.

Aged↗
PubMed2000

The recovery potential of central conduction disorder in hypothyroid rats.

In an aim to detect the dysfunction of central nervous system among rats with varied durations of hypothyroidism and to elucidate the recovery potential after thyroxine replacement, a series of BAEP were conducted and compared with age-matched controls. BAEP was performed in five groups of the hypothyroid animals 1, 3, 5, 7, and 9 months after thyroidectomy respectively. Following initial electrophysiological assessment, thyroxine replacement was administered to each group of hypothyroid rats, and BAEP was performed at two month intervals, up to two successive normal studies or six months after the initiation of therapy, whichever came first. Before thyroxine treatment, prolonged I-V interpeak latency was the most consistent abnormal finding in all groups of hypothyroid rats, and longer hypothyroid state correlated well with more severe central conduction disorder. Hearing impairment was also noted among those with long duration of hypothyroidism. After thyroxine replacement, the central conduction dysfunction usually returned to normal if the hypothyroid state was not more than 5 months in duration. However, when hypothyroid state persisted over 7 months or more, there would be an incomplete recovery for central conduction disorder. The present study brings out the concept of 'therapeutic window' in reversing the central nervous dysfunction caused by hypothyroidism in adult rats.

Age Factors↗
PubMed2000

Hypothyroid myopathy-pathological and ultrastructural study.

Seventeen patients with hypothyroid myopathy were studied before and after thyroxine (T4) treatment. The severity of clinical myopathy was assessed with the aid of a modified rating scale. Laboratory findings including thyroid function, serum creatine kinase (CK), and electromyography were assessed at regular time intervals until a final muscle biopsy was performed. The average period of follow-up was 1.8 years. The authors emphasize: 1) in skeletal muscle pathology of hypothyroidism, the fiber atrophy and increased central nuclear counts are evidence of clinical myopathy during thyroxine treatment; 2) in ultrastructural pathology, the abnormal glycogen accumulation accounts largely for clinical severity and its ongoing resolution is parallel to steady amelioration following T4 therapy, while mitochondrial abnormalities are insignificant in clinical correlation and probably become permanent in some cases with prolonged hypothyroidism; and 3) serial needle biopsies of skeletal muscle are impractical for long-term study of hypothyroid myopathy, but they may be reserved for those patients with a sustained myopathic complaints on T4 therapy.

Adult↗
PubMed1999

Flap complications associated with lamellar refractive surgery.

PURPOSE: Corneal lamellar refractive surgery for myopia reduces the risk of corneal haze but adds to the risk of flap complications. We retrospectively determined the incidence of flap complications in the initial series of eyes undergoing lamellar refractive surgery by one surgeon. We assessed the incidence of flap complications overall, the trend in these complications during the surgeon's learning curve, and the impact of the complications on best spectacle-corrected visual acuity. METHODS: Charts of the first 1,019 eyes that underwent myopic keratomileusis in situ or laser in situ keratomileusis were reviewed for flap complications and visual outcome. RESULTS: Of the 1,019 eyes, 490 eyes underwent myopic keratomileusis in situ, and 529 eyes underwent laser in situ keratomileusis. Eighty-eight (8.6%) of 1,019 eyes had flap-related complications. Six eyes had two complications. Intraoperative complications included irregular keratectomy in nine eyes (0.9%), incomplete keratectomy in three eyes (0.3%), and a free cap in 10 eyes (1.0%). The incidence of intraoperative complications was six (6.0%) in the first 100 consecutive eyes, 14 (2.3%) in the next 600 consecutive eyes (P = .04, chi-square test), and one (0.3%) in the last 300 eyes (P = .03, chi-square test). Postoperative complications included displaced flaps that required repositioning in 20 eyes (2.0%), folds in the flap that required repositioning in 11 eyes (1.1%), diffuse lamellar keratitis in 18 eyes (1.8%), infectious keratitis in one eye (0.1%), and epithelial ingrowth that required removal in 22 eyes (2.2%). The incidence of flap displacement and folds in 200 eyes in which we irrigated under the flap and allowed it to settle without further manipulation averaged 8.5%, whereas the incidence in other groups of 100 consecutive eyes averaged 0.8% (P < .00001, chi-square test). The incidence of diffuse lamellar keratitis was 0.2% in eyes that had undergone myopic keratomileusis in situ and 3.2% in eyes treated by laser in situ keratomileusis (P = .0003, chi-square test). No eye lost 2 or more lines of best spectacle-corrected visual acuity because of flap complications. CONCLUSION: Flap complications after lamellar refractive surgery are relatively common but rarely lead to a permanent decrease in visual acuity. Physician experience with the microkeratome and with the handling of the corneal flap decreases the incidence of flap complications.

Cornea↗
PubMed1998

Prevalence and subtypes of dementia in southern Taiwan: impact of age, sex, education, and urbanization.

To determine the prevalence and subtypes of dementia in southern Taiwan, a two-phase study consisting of a phase I screening survey using the Mini-Mental Status Examination (MMSE) and a phase II diagnostic examination using the CERAD neuropsychological battery and the neurobehavioral examination was conducted. According to the household records, stratified random sampling by the degree of urbanization of the community was used, and 2915 inhabitants aged 65 and over participated in this study. The ICD-10NA criteria for dementia, NINCDS-ADRDA guidelines for Alzheimer's disease (AD), and NINDS-AIREN criteria for vascular dementia (VaD) were employed. Three hundred and ninety-eight persons who had MMSE scores below the cutoff values were recruited into the phase II study, of whom 108 had dementia. The prevalence rate (PR) of dementia was 3.7%, increasing from 1.3% in people 65-69 years old to 16.5% in people 85 years old and older. The age-standardized PR (ASPR) was 4.0%. AD (58 cases, 53.7%, PR=2.0%, ASPR=2.3%) was the most common cause of dementia, followed by VaD (25 cases, 23.1%, PR=0.9%, ASPR=0.9%), and mixed dementia (eight cases, 7.4%). After adjusting for age, sex and education using logistic regression analysis, aging was a significant risk factor for AD, VaD and total dementia. Female sex and illiteracy were significant risk factors for AD only. We concluded that the prevalence of dementia in Taiwan is lower than in the developed countries, which could be due to a relatively young elderly population and a high mortality from dementia in Taiwan. AD is the leading cause of dementia in Taiwan. Considering the high stroke prevalence, the relatively lower prevalence of VaD in Taiwan deserves further investigation.

Age Distribution↗
PubMed1998

Lack of S-adenosylmethionine results in a cell division defect in Escherichia coli.

The enzyme S-adenosylmethionine (SAM) synthetase, the Escherichia coli metK gene product, produces SAM, the cell's major methyl donor. We show here that SAM synthetase activity is induced by leucine and repressed by Lrp, the leucine-responsive regulatory protein. When SAM synthetase activity falls below a certain critical threshold, the cells produce long filaments with regularly distributed nucleoids. Expression of a plasmid-carried metK gene prevents filamentation and restores normal growth to the metK mutant. This indicates that lack of SAM results in a division defect.

Bacterial Proteins↗
PubMed1998

Incidence and subtypes of dementia in southern Taiwan: impact of socio-demographic factors.

OBJECTIVE: To determine the incidence rate (IR) and subtypes of dementia in southern Taiwan. METHODS: From a cohort of 2,915 community inhabitants aged 65 years and over, 2,507 and 2,175 subjects participated in the first- and second-year follow-up surveys, respectively. A two-phase study used the Mini-Mental State Examination in phase I and the Consortium to Establish a Registry of Alzheimer's Disease (CERAD) neuropsychological battery and the neurobehavioral examination in phase II. We applied International Classification of Diseases (ICD)-10NA criteria for dementia, National Institute of Neurological and Communication Disorders and Stroke-Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) guidelines for Alzheimer's disease (AD), and National Institute of Neurological Disorders and Stroke-Association Internationale pour la Recherche et l'Enseignement en Neurosciences (NINDS-AIREN) criteria for vascular dementia (VaD). RESULTS: The annual IR for total dementia was 1.28%, which increased with age from 0.77% for 65- to 74-year-olds to 6.19% for persons aged 85 years or older. AD (25 cases, 41.7%, IR=0.54%) was the most common cause of dementia, followed by VaD (19 cases, 31.7%, IR=0.41%) and mixed dementia (9 cases, 15.0%). After adjusting for sex, increasing age was significantly associated with total dementia and AD (p < 0.01). Illiteracy was associated with a marginally increased risk for total dementia (aRR=1.59, p < 0.1) as was being female for AD (aRR = 1.92, p < 0.1). The 2-year mortality rate was high among the demented (48% in total dementia, 38% in AD, and 60% in VaD). CONCLUSIONS: The age-specific incidence of dementia in Taiwan is approaching that of developed countries and the low prevalence of dementia (especially VaD) may be mainly due to the high mortality. Age was the major risk factor for total dementia and AD. Being female was probably a risk factor for AD, as was illiteracy for total dementia.

Age Distribution↗
PubMed1998

Cranial computed tomography in ischemic stroke patients with and without dementia--a prospective study.

Stroke patients were assessed by brain CT scan, accompanied by demographic and clinical factors to predict the development of dementia following an ischemic episode. Vascular dementia was defined by NINDS-AIREN criteria. From 50 demented and 50 non-demented stroke patients, we analyzed the location of lesion, counted the numbers of lacunae, and semiquantitatively assessed the size of infarction, severity of overall white matter lesions (WML), and degree of brain atrophy. Compared to the non-demented patients, the demented patients: 1) encountered more stroke episodes (p < 0.001); 2) had more lacunae at bilateral basal ganglion (p < 0.001) or thalamus (p < 0.01); and 3) tended to have lesions in left cortex (p < 0.001), particularly a large infarct at the parietal (p < 0.001) or temporal lobe (p < 0.001). Periventricular changes (p < 0.001), subcortical WML (p < 0.001), overall WML (p < 0.001), and brain atrophy (p < 0.05) were also more severe in the demented group. However, no difference existed in demographic factors between the two groups. We concluded that several factors were important in developing dementia following an ischemic stroke, and the order by logistic regression would be: the severity of overall WML, left parietal infarct, and numbers of thalamic lacunae.

Aged↗
PubMed1998

A study of central and peripheral nerve conduction in patients with primary hypothyroidism: the effects of thyroxine replacement.

Somato-Sensory Evoked Potential (SSEP) and Peripheral Nerve Conduction (PNC) studies were performed in twenty patients with primary hypothyroidism to elucidate the changes of central and peripheral nervous systems in hypothyroid state and the effects of thyroxine replacement. Before thyroxine replacement therapy, eleven patients had significantly delayed SSEP (prolonged latencies of N9, N13, or N20), and only three patients had prolonged central conduction time (between N13 and N20). PNC abnormalities with decreased conduction velocity and diminished amplitudes were found in fourteen patients. After thyroxine treatment, both SSEP and PNC studies demonstrated significant improvement and paralleled the clinical neurological amelioration. The central and peripheral conduction velocities returned to normal limits, while the abnormality in amplitude still persisted. There were also discrepancies between SSEP and PNC studies in both the abnormality pattern and the recovery potential. Our observations may suggest: firstly, both the SSEP and PNC studies may be useful, alternative tools in monitoring the neurological disorders in hypothyroidism; and secondly, the pathogenesis of central and peripheral nervous dysfunction in hypothyroidism may be via different mechanisms.

Adult↗
PubMed1998

[A central nerve conduction study in hypothyroidism: before and after thyroxine replacement].

Employing a Nicolet CA 100 machine, 20 patients of primary hypothyroidism were selected for electrophysiological studies, including somato-sensory evoked potential (SSEP), brainstem auditory evoked potential (BAEP), and visual evoked potential (VEP), to assess the central nerve conduction before and after administration of the thyroid hormone. Before thyroxine replacement therapy, the latencies of N9, N13, and N20 in SSEP showed significant delay, while the central conduction time (CCT) merely had a tendency of prolongation. In BAEP, the peak and interpeak latencies delayed significantly. Additionally, the latency and amplitude of VEP also had significant difference between patients and controls. After thyroxine replacement, the SSEP, BAEP, and VEP studies revealed significant improvement, in correlation with clinical amelioration. In conclusion, the central nerve conduction would be affected in primary hypothyroidism and the improvement was usually the case, reflecting the clinical recovery after appropriate treatment. The electrophysiological study provides an objective method for monitoring the function of central nervous system in hypothyroidism before and after thyroxine treatment.

Adult↗
PubMed1997

Effectiveness of low-dose ASA in prevention of secondary ischemic stroke, the ASA Study Group in Taiwan.

This randomized double-blind controlled study was carried out to investigate the effect of 100 mg acetylsalicylic acid (ASA) per day on the secondary prevention of ischemic stroke. Patients who suffered a first ischemic stroke from 13 participating hospitals were enrolled. They were independent or only partially dependent in activities of daily living and all had received brain CT for diagnosis. Eligible patients were randomly allocated to the 100 mg ASA or the nicametate citrate (a vasodilator) groups, and trial medications were started within three to six weeks after the onset of stroke. The primary end point was cerebral reinfarction, and intracranial hemorrhage was classified as an adverse event. Four hundred and sixty-six patients participated in this study; and 222 cases (136 males and 86 females) were allocated to the ASA group while 244 cases (150 males and 94 females) were assigned to the nicametate group. No significant difference in baseline characteristics between the two groups was observed. Cerebral reinfarction developed 6.3% (14/222) in the ASA group and 11.9% (29/244) in the nicametate group. According to the Cox's proportional hazards model, the estimated risk ratio (ASA group vs. nicametate group) was 0.538, with a 95% confidence interval of 0.284-1.019. The result was of borderline statistical significance. The risk for cerebral reinfarction was reduced by almost 50% among those who took 100 mg ASA versus those who took nicametate.

Aged↗
PubMed1997

A longitudinal study of central and peripheral nerve conduction in hypothyroid rats.

In order to detect the dysfunction of central and peripheral nervous systems among rats with varied duration of hypothyroidism and to elucidate the pattern of recovery after thyroxine replacement, a series of BAEP and PNCS (Peripheral Nerve Conduction Study) were conducted and compared with age-matched controls. BAEP and PNCS were performed in three groups of hypothyroid animals 1, 3 and 5 months after thyroidectomy, respectively. Following initial electrophysiological assessment, thyroxine replacement was administered to each group of hypothyroid rats, and BAEP and PNCS were performed at two month intervals, up to two successive normal studies, or six months after the initiation of therapy, whichever came first. For BAEP, prolonged I-V interpeak latency was the most consistent abnormal finding in all groups of hypothyroid rats, and longer hypothyroid states correlated well with more severe central conduction disorder. Nevertheless, these abnormalities usually returned to normal after thyroxine replacement if the duration of hypothyroidism was less than 5 months. Regarding PNCS, all groups of thyroidectomized rats showed normal conduction before and after thyroxine therapy. The present study indicates that, in rats: (1) the peripheral nervous system seems to be more resistant to hypothyroidism than the central nervous system, or (2) the pathogenesis of central and peripheral nerve dysfunction in hypothyroid rats may occur through different mechanisms.

Age Factors↗
PubMed1997

The psychiatric manifestation of Creutzfeldt-Jakob disease.

Creutzfeldt-Jakob disease (CJD) is considered to be very rare in the population, and the psychiatric manifestation of the disease even rarer with only one report in the past few years in Taiwan. To clarify whether the psychiatric manifestation of CJD is really rare or whether it is neglected in Taiwan, the authors reviewed the discharge notes of patients who had been admitted to a neurological unit in the past 15 years and conducted a chart review of the patients of CJD supported by the clinical courses, EEG finding and brain biopsies. An inquiry was made by telephoning their families to follow up their condition after discharge. Five of the 8 cases with CJD had psychiatric symptoms including changes of mood, thought, behavior and perception during their course of illness. Four cases had been sent to the psychiatric unit and received treatment under several kinds of psychiatric diagnoses. Two patients had been admitted to the psychiatric unit and one had received electroconvulsive treatment. Two of the patients had been suspected to be the victims of neuroleptic malignant syndrome. It is likely that it is psychiatrists who will meet CJD patients first in the early stages of disease. CJD should be kept in mind and EEGs with detailed neurological checkups should be completed, if the cognitive functions of the patients with unusual neurological symptoms deteriorate quickly and their psychiatric symptoms fail to respond to any treatment.

Aged↗
PubMed1996

Three-dimensional statistical analysis of sulcal variability in the human brain.

Morphometric variance of the human brain is qualitatively observable in surface features of the cortex. Statistical analysis of sulcal geometry will facilitate multisubject atlasing, neurosurgical studies, and multimodality brain mapping applications. This investigation describes the variability in location and geometry of five sulci surveyed in each hemisphere of six postmortem human brains placed within the Talairach stereotaxic grid. The sulci were modeled as complex internal surfaces in the brain. Heterogeneous profiles of three-dimensional (3D) variation were quantified locally within individual sulci. Whole human heads, sectioned at 50 micrometer, were digitally photographed and high-resolution 3D data volumes were reconstructed. The parieto-occipital sulcus, the anterior and posterior rami of the calcarine sulcus, the cingulate and marginal sulci, and the supracallosal sulcus were delineated manually on sagittally resampled sections. Sulcal outlines were reparameterized for surface comparisons. Statistics of 3D variation for arbitrary points on each surface were calculated locally from the standardized individual data. Additional measures of surface area, extent in three dimensions, surface curvature, and fractal dimension were used to characterize variations in sulcal geometry. Paralimbic sulci exhibited a greater degree of anterior-posterior variability than vertical variability. Occipital sulci displayed the reverse trend. Both trends were consistent with developmental growth patterns. Points on the occipital sulci displayed a profile of variability highly correlated with their 3D distance from the posterior commissure. Surface curvature was greater for the arched paralimbic sulci than for those bounding occipital gyri in each hemisphere. On the other hand, fractal dimension measures were remarkably similar for all sulci examined, and no significant hemispheric asymmetries were found for any of the selected spatial and geometric parameters. Implications of cortical morphometric variability for multisubject comparisons and brain mapping applications are discussed.

Aged↗
PubMed1996

Indoor burning coal air pollution and lung cancer--a case-control study in Fuzhou, China.

A case-control study on risk factors for lung cancer was carried out in Fuzhou, China. One-hundred and two newly-diagnosed primary lung cancer cases in urban Fuzhou (78 male and 24 female cases) were matched with 306 population-based controls. The primary histological types were adenocarcinomas (57 cases, 55.9%) and squamous cell carcinomas (39 cases, 38.2%). Controls were obtained from the general population by random, stratified sampling and consisted of noncancer cases matched for sex, ethnicity and age. Cases and controls were interviewed by trained professionals using a standardized questionnaire. Information was obtained on: smoking habits, living conditions, history of respiratory diseases, air pollution, and 40 other variables. The data were evaluated by conditional logistic regression analysis. The major risk factors for lung adenocarcinoma were: indoor air pollution from burning coal, chronic bronchitis, and high economic income. The risk factors for lung squamous cell carcinoma were: amount of cigarettes smoked per day, "deep inhalation", a history of exposure to environmental tobacco smoke (ETS) before 20 years of age, burning coal indoors, and high economic income. The results showed that the major risk factors for lung cancer in Fuzhou were: burning coal indoors, smoking, exposure to ETS before 20 years of age, chronic bronchitis, and high economic income. Cigarette smoking significantly increased the risk of lung squamous cell carcinoma, but had no significant association with the risk of lung adenocarcinoma. In summary, our research supports the hypothesis that smoking and indoor air pollution are the major risk factors for lung cancer in Fuzhou. Burning coal indoors and smoking were associated with lung cancer mortality in a major city in southern China.

Adult↗
PubMed1996

Prevalence of dementia in an urban area in taiwan.

This two-stage epidemiologic study was to investigate the prevalence and types of dementia among elderly people in the Saa-Min district of Kaohsiung City in Taiwan. In stage one, the Chinese Mini-Mental Status Examination (CMMSE) and Blessed Dementia Rating Scale were employed. In stage two, a comprehensive neurobehavioral examination and neuropsychologic tests were administered by neurologists and neuropsychologists. Dementia was defined by DSM-III-R criteria. The National Institute of Neurological and Communication Disorders and Stroke-Alzheimer's Disease and Related Disorders Association guidelines for Alzheimer's disease (AD) and the National Institute of Neurological Disorder and Stroke-Association international pour la Recherche et l'Enseignement en Neurosciences criteria for vascular dementia (VaD) were applied. A total of 1,016 randomly selected elderly people participated in phase one: 131 people with CMMSE below cutoff values participated in phase two, of whom 45 were confirmed to have a form of dementia. The prevalence of dementia in this sample was 4.4% (3.2% in men and 5.8% in women): 2.0% for those 65 to 74 years old, 8.3% for those 75 to 84 and 24.4% for those > or = 85 years old; 6.0% for those who were illiterate, 3.3% for those who attended grade-school; and 2.8% for those who finished junior-high-school. AD (22 cases, 48.9%) was the most common cause of dementia, followed by VaD (11 cases, 24.4%) and mixed dementia (MIX: 5 cases, 11.1%). Old age and being female were significant high risk factors for AD. Medical history indicated that stroke and hypertension were significant risk factors for VaD. A relatively high prevalence of dementia was observed in this study, probably because we assessed neurobehavior in great detail. Although AD was the leading cause of dementia in the present population sample. VaD and MIX also comprised an important proportion, reflecting the high prevalence of stroke in Taiwan. Older women had high risk for AD, not for VaD; and those with a history of stroke and hypertension had high risk for VaD, not for AD.

Aged↗