PubMed Health⌕ Search

Biomedical subjects

P N Wang

Publications and source records attributed to P N Wang.

At least 19 recordsLinked to original sources
PubMed2007

Enhancement of intracellular delivery of CdTe quantum dots (QDs) to living cells by Tat conjugation.

Quantum dots (QDs), as novel fluorescence probes, have shown a great potential for bio-molecular labeling and cellular imaging. To stain cellular targets, the sufficient intracellular delivery of QDs is required. In this work the tat, a typical membrane-permeable carrier peptide, was conjugated with thiol-capped CdTe QDs to form CdTe Tat-QDs, and the intracellular deliveries of CdTe QDs or CdTe Tat-QDs were compared in human hepatocellular carcinoma (QGY) cells and human breast cancer (MCF7) cells in vitro by means of confocal laser scanning microscopy. Added into the cell dishes, both QDs and Tat-QDs adhered to the outer leaflet of the plasma membrane of cells within a few minutes, but the binding amount of Tat-QDs was obviously higher than that of QDs. Then both QDs and Tat-QDs can penetrate into cells, and their cellular contents increased with incubation time but both saturated after 3 hours incubation. However the cellular levels of Tat-QDs were higher than those of QDs, with the ratio of 2.1 (+/-0.3) times in QGY cells and 1.5 (+/-0.2) times in MCF7 cells, demonstrating the enhancing effect of Tat conjugation on the intracellular delivery of QDs.

Cadmium↗
PubMed2006

Refractive index measurement for biomaterial samples by total internal reflection.

The refractive index of biological tissue is a fundamental parameter in applications of optical diagnosis and laser treatments. In the present work, the refractive indices and thermo-optic coefficients of some basic biomaterials, such as blood plasma, haemoglobin solution and lipid membrane, were studied by the method of total internal reflection at the wavelengths of 532 and 632.8 nm that are the most frequently used laser wavelengths in the biomedical field. The effects of the sample concentration and the temperature on refractive index were measured, and empirical relationships were summarized, accompanied by a theoretical explanation based on molecular polarization theory. The results provide some fundamental data for the refractive indices of these biomaterials under variant conditions, and also demonstrate that the total internal reflection method is a feasible and reliable way to measure the refractive indices of biological samples.

Biocompatible Materials↗
PubMed2006

Prediction of Alzheimer's disease in mild cognitive impairment: a prospective study in Taiwan.

The relationship between apolipoprotein E (ApoE) and clinical manifestations of mild cognitive impairment (MCI) has not been investigated in non-Caucasian populations. This prospective study was conducted in an ethnic Chinese population to evaluate the correlations of ApoE genotype, cognitive performance, medial temporal structure volumes, and clinical outcome in amnestic MCI. Twenty normal elders, 58 MCI, and 20 mild Alzheimer's disease (AD) patients received neuropsychological, MRI, and ApoE genotype assessments at baseline. Patients with MCI had intermediate cognitive performance and hippocampal volumes between those in normal and AD groups. In each diagnostic group, epsilon4 carriers (E4+) consistently had smaller hippocampal volume than non-carriers (E4-) did. Nineteen MCI subjects (32.7%) converted to AD during the 3-year study period. Compared with MCI non-converters and E4- MCI converters, E4+ MCI converters had the smallest hippocampal volume. However, epsilon4 was not a predictor for AD. Both cognitive performance and hippocampal volume were predictive for progression to AD. However, stepwise Cox regression model integrating both neuropsychological and radiological variables showed that global cognitive performance was the only significant predictor for AD. A poor global cognitive score may be more crucial than a small hippocampal volume in the prediction of AD.

Aged↗
PubMed2005

Cholinesterase inhibitor affects the amyloid precursor protein isoforms in patients with Alzheimer's disease.

An altered platelet ratio of amyloid precursor protein (APP) isoforms might be a diagnostic, predictive, or therapeutic marker for Alzheimer's disease (AD). Our purpose was to test the hypothesis that this ratio might serve as a therapeutic marker for AD patients treated with the cholinesterase inhibitor, galantamine. Thirty-nine patients (mean age 76.6 +/- 9.4 years) with AD were treated with galantamine for 12 weeks. Patients were evaluated at baseline, 4 and 12 weeks by cognitive testing along with a determination of their platelet APP isoform ratio. Western blotting was performed to calculate the APP isoform ratio. At the end of the treatment, cognitive scores significantly improved, and the ratio of the high-molecular-weight (130 kDa) isoform to the low-molecular-weight (110-106 kDa) isoforms increased. These results suggest that cholinesterase inhibition might be involved in APP processing.

Aged↗
PubMed2004

Estrogen-metabolizing gene COMT polymorphism synergistic APOE epsilon4 allele increases the risk of Alzheimer disease.

Alzheimer disease (AD) is a polygenic multifactorial disorder. Several studies suggested that the neuroprotective effect of estrogen was based on an APOE-dependent mechanism. The goals of the current study were to determine if the genes involved in estrogen metabolism were linked to the risk of AD and find out if there was an interaction between estrogen-metabolizing gene polymorphisms and the APOE epsilon4 allele in the risk of prevalent AD. We investigated 66 patients with AD and 86 age- and gender-matched normal subjects. The polymorphisms of APOE and estrogen-metabolizing genes CYP17, CYP1A1 and COMT were examined. No association was found between each estrogen-metabolizing gene polymorphism and AD. However, the COMT HH genotype and APOE epsilon4 allele had a synergistic effect on the risk of AD. Taking subjects with epsilon4-epsilon4-/HH- as reference, the risk of developing AD in subjects with one epsilon4 allele (epsilon4+epsilon4-/HH-) was 2.6 (95% confidence interval, CI, 0.7- 9.1); however, the risk in subjects with both HH and one epsilon4 (epsilon4+epsilon4-/HH+) increased to 3.6 (95% CI 1.2-10.6). The subjects with homozygous epsilon4 still had the highest risk in developing AD (odds ratio 6.6, 95% CI 0.6-69.6). The p value of the linear trend test for this regression model was 0.004. It is possible that a high metabolism of estrogen by COMT may have reduced the protective effect of estrogen in AD. Further studies to clarify this interaction may improve our understanding of the generic risks for AD.

Aged↗
PubMed2004

ApoE epsilon4 allele is associated with incidental hallucinations and delusions in patients with AD.

Of 135 patients with Alzheimer disease (AD), 56 without psychiatric symptoms at the first visit were followed for a mean period of 51.9 +/- 10.3 months to identify incident psychiatric symptoms. The hazard ratios of ApoE epsilon4 allele in developing psychiatric symptoms were calculated by Cox regression hazard analyses. The presence of the ApoE epsilon4 allele carried a 19.0-fold risk for developing hallucinations and a 3.4-fold risk for delusions.

Aged↗
PubMed2001

Clonality analysis using X-chromosome inactivation patterns by HUMARA-PCR assay in female controls and patients with idiopathic thrombocytosis in Taiwan.

OBJECTIVE: Analysis of X-chromosome inactivation patterns (XCIPs) is a useful tool in the diagnosis of clonal disorders. The human androgen receptor (HUMARA) locus is especially useful for clonality study. The present study was conducted 1) to determine the heterozygosity rate for HUMARA locus in Taiwanese women, 2) to determine the frequency of excessive skewing in different cell types, and 3) to determine the utility of XCIPs in the differential diagnosis of thrombocytosis. PATIENTS AND METHODS: XCIPs by HUMARA-PCR assay were performed on purified granulocytes and T cells from 73 female patients presenting with idiopathic persistent thrombocytosis (IT), 10 patients with reactive thrombocytosis (RT), and 46 bone marrow samples from female controls. XCIPs of buccal mucosa cells were also compared with those of T cells in 57 patients with IT. The percentage of clonal granulocytes was calculated after correcting for the degree of Lyonization in T cells. RESULTS: The heterozygosity rate for the HUMARA gene was 89.1% in Taiwanese females. The median age of informative IT patients and controls was 59 (18-92) and 58 (19-89), respectively. Excessive skewing (allele ratio <0.33) was more frequent in granulocytes than in T cells in both controls (12/43 vs 9/43, p = 0.080) and IT patients (56/64 vs 25/64, p < 0.001). XCIPs were the same for both buccal mucosa and T cells in 43 patients but were different in 14 patients. Of the 43 informative controls, 31 had a polyclonal pattern; an ambiguous pattern was found in nine; and the remaining three, aged 71, 73, and 80, respectively, had a clonal pattern. A clonal pattern was found in 42 IT patients, a polyclonal pattern in 12, and an ambiguous pattern in 10 of the 64 IT patients. The frequency of clonal, polyclonal, and ambiguous patterns in the 40 IT patients with age < or = 65 was 55.0%, 30.0%, and 15.0%, respectively. None of the IT patients aged >65 had a polyclonal disease. IT patients aged >65 had a significantly higher frequency of clonal pattern (p = 0.030) and a significantly lower frequency of polyclonal pattern (p = 0.002) than those with age <65. Of the eight heterozygous patients with RT, one aged 80 exhibited a clonal pattern, and the remaining seven had a polyclonal pattern. CONCLUSIONS: The present study on Taiwanese females showed a heterozygosity rate of 89.1% for the HUMARA gene. Our results confirmed that IT is a heterogeneous disorder in terms of clonality. Twenty-three percent of IT patients exhibited a greater than 20% difference in allele expression for buccal mucosa and T cells. Presence of a clonal XCIP in young patients with IT can serve as a positive marker for the diagnosis of clonal thrombocytosis, and elderly patients with polyclonal XCIPs are unlikely to have essential thrombocythemia.

Adolescent↗
PubMed2001

Parenteral nutrition support after bone marrow transplantation: comparison of total and partial parenteral nutrition during the early posttransplantation period.

OBJECTIVE: Bone marrow transplantation (BMT) usually is indicated if the patient's malignant disease involves the marrow or if hazard to the normal marrow is the limiting factor in the aggressive treatment of disease. The success of BMT depends on a complete team with all the resources needed to ensure optimal results. Aggressive nutrition support after BMT is very important. Adequate parenteral nutrition, total (TPN) or partial, followed by enteral nutrition according to the patient's gastrointestinal function is the important principle. METHODS: Between 1996 and 2000, 60 patients, 46 male and 14 female, received BMT in Chang Gung Memorial Hospital. Their ages ranged from 6 to 54 y. Standard TPN was used in 40 patients after BMT, and partial parenteral nutrition was used in the remaining 20 patients. TPN was enriched with branched-chain amino acids (BCAA) when the patient's liver functions were impaired, and cyclic TPN was shifted when the patient's liver functions persistently deteriorated. RESULTS: Most patients improved their nutrition status and increased their body weights, especially those receiving TPN. The patients receiving partial parenteral nutrition decreased their visceral proteins significantly during the course of parenteral nutrition. The BCAA-TPN can maintain a patient's visceral protein better than standard TPN. Only two patients expired because of graft rejection and sepsis; their body weights and nutrition status showed deterioration despite aggressive nutrition support. CONCLUSIONS: We conclude that the nutrition support for patients with BMT is related to the success of marrow transplantation. Parenteral nutrition support, especially with TPN, is important because of frequent gastrointestinal dysfunction during the posttransplantational period, and it is better at maintaining the nutrition status and body weights of patients after BMT. An oral diet can be resumed after the patient's gastrointestinal function has improved and it can be tolerated.

Adolescent↗
PubMed2001

Association analysis of the 5-HT6 receptor polymorphism C267T with depression in patients with Alzheimer's disease.

A significant increase of 267C allele of the 5-HT(6) receptor gene has been reported in patients with Alzheimer's disease (AD). Because a deficit in serotonergic neurotransmission is involved in major depression, we tried to find out whether 267C allele is associated with depressive disorders in AD. A psychiatrist interviewed all AD patients and their caregivers for evidence of depression using a Chinese version of the Standard Clinical Interview for DSM-III-R. The difference in the 5-HT(6) genotype or allele distributions between the AD patients with depressive disorders (n = 25) and those without (n = 120) was not significant.

Aged↗
PubMed2001

[Spectroscopic study on the high voltage fast pulsed discharge of nitrogen, ammonia or their mixture].

The emission spectra from the pulsed discharge plasma of nitrogen, ammonia or their mixture were measured. In the discharge of pure nitrogen gas, as the pressure increased, the discharge volume decreased and more dissociation of nitrogen molecules occurred due to the higher energy density. In the discharge of ammonia, N,N+ and NH+ were observed, but no NH2 and NH3 were detected, indicating that ammonia, which has the lower dissociation and ionization energies as compared to nitrogen, was highly dissociated. The discharge of the mixture of N2 and NH3 was also studied. The dependence of the dissociation of nitrogen on the ratio of nitrogen to ammonia was investigated by emission spectra. The optimal ratio for nitrogen dissociation was obtained. The advantage of using the mixture of nitrogen and ammonia in the synthesis of nitrides was discussed.

Ammonia↗
PubMed2000

Effects of estrogen on cognition, mood, and cerebral blood flow in AD: a controlled study.

OBJECTIVE: To examine the effects of estrogen therapy on cognition, mood, and cerebral blood flow in patients with AD. BACKGROUND: Some studies have suggested estrogen may be effective in the treatment of AD. However, most of these studies were not controlled adequately. METHODS: Fifty female AD patients were recruited in a randomized, double-blind, placebo-controlled 12-week trial. Each member of the estrogen-treated group received conjugated estrogen (Premarin) 1.25 mg/day. The primary outcome measures were the Cognitive Ability Screening Instrument (CASI), Clinical Dementia Rating (CDR), and Clinician Interview-Based Impression of Change (CIBIC-plus). The secondary outcome measures were Behavioral Pathology in Alzheimer's Disease (BEHAVE-AD), Hamilton Anxiety Rating Scale (HARS), Hamilton Depression Rating Scale (HDRS), and 99mTc hexamethylpropylene amine oxime SPECT of the brain. RESULTS: No meaningful differences were found between the outcome measures (CASI, CDR, CIBIC-plus, BEHAVE-AD, HARS, HDRS, and cerebral blood flow) taken from the estrogen-treated group and those from the control group. CONCLUSION: A 1.25-mg/day dose of Premarin administered for 12 consecutive weeks does not produce a meaningful effect on cognitive performance, dementia severity, behavior, mood, and cerebral perfusion in female AD patients. Because estrogen therapy has been suspected of yielding adverse effects, and its therapeutic effectiveness is in doubt, additional evaluation of its role in AD treatment ought to be conducted.

Affect↗
PubMed2000

Chronic daily headache in Chinese elderly: prevalence, risk factors, and biannual follow-up.

OBJECTIVE: To investigate the prevalence, risk factors, and prognosis of chronic daily headache (CDH) in a population of elderly Chinese subjects. METHODS: A community-based survey of registered residents > or =65 years old (n = 2,003) in two townships of Kinmen Island in 1993. A neurologist used a structured questionnaire and clinical interview to make the diagnosis of headache. Subjects who had headaches > or =15 days/month for > or =6 months in the previous year were considered to have CDH. CDH was further classified into chronic tension-type headache (CTTH), CDH with migrainous features (CDH/MF), and other CDH. Person-to-person biannual follow-up of the subjects with CDH was done in June 1995 and August 1997. RESULTS: A total of 1,533 people (77%) participated in our prevalence study. Sixty subjects (3.9%) fulfilled the criteria for CDH, with a higher prevalence in women (F/M: 5.6%/1.8%, p < 0.001). Of these subjects, 42 (70%) had CTTH, 15 (25%) had CDH/MF, and 3 (5%) had other CDH. Only 23% of those with CDH had consulted physicians for their headaches in the previous year. Multivariate logistic regression revealed the significant risk factors for CDH to be analgesic overuse (OR = 79), a history of migraine (OR = 6.6), and a Geriatric Depression Scale-Short Form score of > or =8 (OR = 2.6). The follow-up results in 1995 and 1997 showed that about two-thirds of the subjects still had CDH. Analgesic overuse (relative risk = 1.6) in 1993 was a significant predictor of persistent CDH at follow-up. CONCLUSIONS: A total of 3.9% of this elderly population had CDH, with CTTH being the most common subtype. Almost two-thirds of those with CDH had persistent frequent headaches at follow-up. Analgesic overuse was a significant predictor of a poor outcome.

Aged↗
PubMed2000

Subjective memory complaint in relation to cognitive performance and depression: a longitudinal study of a rural Chinese population.

OBJECTIVES: To examine the associations of subjective memory complaint (SMC) in old age with (a) objective test performance, (b) past and subsequent cognitive decline, and (c) depression. DESIGN: A group of community residents were examined twice during a 3-year period. SETTING: Two townships on a rural Chinese islet. PARTICIPANTS: A total of 543 men and women aged 65 years and older. MEASUREMENTS: During each examination, neurologists interviewed and examined all participants for dementia and asked the question, "Do you have trouble with your memory?" In addition, research assistants administered (a) the Cognitive Abilities Screening Instrument (CASI) to assess cognitive abilities, including long-term memory (LTM) and short-term memory (STM), and (b) the Geriatric Depression Scale-Short Version (GDS-S) to assess symptoms of depression. RESULTS: At each examination, almost half of the subjects acknowledged having trouble with their memory (the SMC+ group). At both examinations, the SMC+ group scored significantly lower on the CASI and significantly higher on the GDS-S than the SMC- group. However, the presence of SMC was not associated with faster cognitive decline over the past or subsequent 3 years. There were no consistent associations between SMC and the demographic variables of age, gender, and education at the two examinations. Logistic regression analysis showed that SMC was associated with poorer memory test scores after controlling for gender, age, education, and depression. CONCLUSIONS: SMC was associated with poorer objective memory performance even after controlling the effect of depression and demographic data, but SMC did not predict faster cognitive decline or dementia over 3 years.

Aged↗
PubMed2000

Immunoglobulin D multiple myeloma.

BACKGROUND: Immunoglobulin D (IgD) multiple myeloma (MM) is rare, accounting for less than 2% of all patients with MM in Western countries. In Taiwan, the frequency and clinicopathologic features of IgD MM have not yet been reported. METHODS: The clinicopathologic features and treatment outcome of patients with IgD MM diagnosed between January 1, 1982, and December 31, 1998, in Chang Gung Memorial Hospital were retrospectively reviewed. Nineteen patients with IgD MM were diagnosed. Of those patients, the medical records of 16 were available for review. RESULTS: Most of the patients were male (11/16) with a median age of 59 years. The most common presenting features included bone pain (56%), gastrointestinal discomfort (38%), general malaise (38%), and body weight loss (25%). The majority of patients had cytopenia (88%), renal function impairment (75%), hypercalcemia (63%), hyperuricemia (69%), elevated beta 2-microglobulin levels (86%), and Bence Jones proteinuria (92%). Serum protein electrophoresis showed an M-peak in 9 cases (9/12), whereas immunoelectrophoresis or immunofixation identified an IgD monoclonal gammopathy in all 16 patients. All of the M-proteins were of a lambda-light chain type. The IgD level ranged between 584 and 129,000 IU/ml (normal, < 100 IU/ml). All the patients had stage III disease except one (stage I). Four patients were still alive at the time of this analysis. The median survival time was 12 months. Infection was the leading cause of death (50%). CONCLUSION: The present series showed that IgD MM had aggressive clinical features, male predominance, a high frequency of renal function impairment, high incidence of M-protein undetected by serum protein electrophoresis, a predilection for lambda-light chains, and a short period of survival.

Adult↗
PubMed1999

ApoE genotype in relation to AD and cholesterol: a study of 2,326 Chinese adults.

OBJECTIVE: To calculate the frequencies of apolipoprotein E (apoE) alleles in a large Chinese community sample and to compare the serum cholesterol levels of epsilon2, epsilon3, and epsilon4 carriers. BACKGROUND: In comparison with Western populations, a lower frequency of the apoE epsilon4 allele among the Chinese has been proposed as one factor for the lower prevalence of AD found in Chinese populations, but there are insufficient Chinese data on epsilon4 frequency that are based on large community samples. In addition, although Western studies have repeatedly found a lower cholesterol level in epsilon2 carriers and a higher cholesterol level in epsilon4 carriers in comparison with epsilon3 homozygotes, two Chinese studies have yielded inconsistent findings between them. METHODS: During the incidence phase of an epidemiologic survey of several neurologic disorders in a Chinese community, the authors took blood samples from 2,326 participants to determine the apoE genotypes and to measure cholesterol levels. RESULTS: The allelic frequencies of epsilon2, epsilon3, and epsilon4 were 11.8%, 76.4%, and 11.8% among 17 AD patients, and 7.8%, 84.1%, and 8.1% for the entire sample. The mean cholesterol level of the epsilon2 carriers was significantly lower, and that of the epsilon4 carriers significantly higher, than that of the epsilon3 homozygotes. CONCLUSIONS: The obtained epsilon4 rate of 8.1% is lower than most of the Western findings, and this may account in part for the lower prevalence of AD found among the Chinese. The associations between the apoE genotype and serum cholesterol level are similar between Chinese and white populations.

Aged↗
PubMed1999

Ossification of the posterior longitudinal ligament of the spine. A case-control risk factor study.

STUDY DESIGN: A case-control study. OBJECTIVES: To determine the risk factors for ossification of the posterior longitudinal ligament (OPLL) of the spine. SUMMARY OF BACKGROUND DATA: Previous epidemiologic studies conducted in Japan showed consuming vegetable protein and salt was a risk factor for OPLL. Dietary habits of the Taiwanese and Japanese people are similar. Whether the similar dietary habits play an important role in the high prevalence of OPLL in Taiwan was of interest. METHODS: A case-control study was conducted in a tertiary teaching hospital. The study included 98 consecutive cervical spine patients with OPLL, with 98 age-matched patients with cervical spondylosis serving as control subjects. Radiologic examinations, clinical interviews, physical examinations, and risk factor questionnaires were administered to all the participants. RESULTS: Compared with incidence in the control patients, the frequency of the ossification of the anterior longitudinal ligaments was significantly higher in OPLL patients with OPLL (31% vs. 19%; P = 0.049), but there was no difference in incidence of ossification of the ligamentum flavum (13.3% vs. 16.3%; P = 0.546). More OPLL patients preferred a high-salt diet (OPLL/CS, no:somewhat:yes = 23/38:18/25:57/35;, X2 for trend = 6.3; P = 0.001) and pickled foods (OPLL/CS, no:somewhat:yes = 39/56:11/11:48/31; X2 for trend = 6.7; P = 0.0099). Fewer patients with OPLL consumed meat daily (63% vs. 79%; P = 0.018). High-salt diet (odds ratio = 2.62) and daily meat intake (odds ratio = 0.39) showed persistent association with OPLL in a multivariate logistic regression. CONCLUSIONS: The similar dietary habits, particularly a high-salt and low meat intakes, may partially explain the high prevalence of OPLL in Taiwan and Japan. Modifying dietary habits may help prevent this disease, especially in those high-risk populations.

Aged↗