Biomedical subjects

S J Wang

Publications and source records attributed to S J Wang.

At least 19 recordsLinked to original sources

PubMed2006

A high yield robotic synthesis of 9-(4-[18F]-fluoro-3-hydroxymethylbutyl)guanine ([18F]FHBG) and 9-[3-[18F]fluoro-1-hydroxy-2-propoxy)methyl]guanine([18F] FHPG) for gene expression imaging.

The aim of this study was to develop an automated synthesis of 9-(4-[(18)F]-fluoro-3-hydroxymethylbutyl)guanine ([(18)F]FHBG) and 9-[(3-[(18)F]fluoro-1-hydroxy-2-propoxy)methyl]guanine ([(18)F]FHPG) using a Scanditronix Anatech RB III robotic system. [(18)F]HF was produced via (18)O(p, n)(18)F using a Scanditronix MC17F cyclotron. On average, a typical run produced [(18)F]FHBG and [(18)F]FHPG with an uncorrected radiochemical yield of 19% and 16%, respectively, at end of synthesis (EOS) from irradiation of 95% enriched [(18)O]water. The total synthesis time was 80 min. The retention time of [(18)F]FHBG and [(18)F]FHPG (the radio-peak) was 3.9 and 4.0 min, respectively, which was consistent with the [(19)F]FHBG and [(19)F]FHPG ultraviolet peak. The radiochemical purity was greater than 97%. A robotic, automated method for [(18)F]FHBG and [(18)F]FHPG radiosynthesis is therefore feasible. The radiation burden for the operator can be reduced as much as possible. Sufficient radioactivities of [(18)F]FHBG and [(18)F]FHPG could be obtained for non-invasive monitoring the expression of transfected gene in vivo with positron emission tomography (PET).

Equipment Design↗

PubMed2005

The scaling behavior of the molecular parameters of the hyperbranched polymers made by self-condensing vinyl polymerization.

The hyperbranched polymers can be made by self-condensing vinyl polymerization without gelation transition. The average molecular weights, as well as the average sizes, can reach infinite values as the reaction is quantitatively completed, and the scaling forms of the molecular parameters should exist. In the paper, based on a recursion formula, the scaling form of the number fraction distribution and the number of the n-mers are given analytically as the conversion of double bonds is near 1. The mean square radius of gyration for very large hyperbranched polymers is calculated explicitly to give a scaling exponent. Finally, a scaling relation associated with the fractal dimension and the polydispersity exponent is given clearly.

Journal Article↗

PubMed2005

Optimizing double emulsion process to decrease the burst release of protein from biodegradable polymer microspheres.

The process parameters such as the compositions of inner and outer aqueous phase and emulsification technique of the primary emulsion were optimized to decrease the burst release of BSA from biodegradable polymer microspheres in double emulsion method. It was found that diminished burst release of -14% was achieved for the microspheres produced by formulations, where no phosphate was present in the inner water phase (non-buffered system). Primary emulsion made by probe sonication rather than homogenization or mechanical stirring led to microspheres with insignificant burst effect. Microspheres obtained using 0.1% aqueous Tween 80 solution as the outer aqueous phase, frequently exhibit reduced burst effect of 2.7%. Low microsphere yield (52.1%), however, was observed. Microsphere yield was, therefore, enhanced by addition of additive such as sodium chloride, glucose or mannitol into the outer aqueous phase. Decrease in BSA entrapment was observed in the presence of sodium chloride, but reduction in entrapment efficiency was observed in the case of glucose. Burst release increased from 2.7% to 9.5% or 3.4% as 2.5% sodium chloride or 7.5% glucose was added into the outer aqueous phase respectively. Marked burst release (>20%) was observed in the presence of additive of higher concentration independent of sodium chloride or glucose. As far as surfactant type was concerned, diminished burst was found when PVP or Tween 80 rather than PVA was utilized as the surfactant during microsphere preparation. In addition to PLGA, the copolymers of L-lactide (LLA) and dimethyl trimethylene carbonate (DTC) or trimethylene carbonate (TMC) were also evaluated. Insignificant burst effect was found for the microspheres composed of DTC or TMC copolymers.

Animals↗

PubMed2005

Posterior cranial fossa crowdedness is related to age and sex: an magnetic resonance volumetric study.

PURPOSE: To measure 3-dimensional (3D) posterior cranial fossa (PCF) crowdedness and to evaluate the effect of age, sex, and body height on PCF. MATERIAL AND METHODS: Fifty-two healthy volunteers (24 M and 28 F; mean age 55.4 +/- 17.2 years; range 24-82 years) were recruited. Using a semi-automated magnetic resonance technique, we calculated a PCF crowdedness index (CI) as the ratio of hindbrain (HB) volume to PCF volume x 100% and correlated this index with age, sex, body height, and other crowdedness parameters. RESULTS: The mean PCF CI was 93.7 +/- 2.7%. Women had a more crowded PCF than men (95.0+1.7% versus 92.1 +/- 2.7%; P<0.001). PCF CI declined with age for both men (r = -0.61; P=0.002) and women (r = -0.68; P<0.001). The association with age--but not HB volume was maintained after we controlled for sex and body height. On multiple regression, both age and sex accounted for 57.5% of the PCF CI variance. CONCLUSION: Our study shows that PCF CI is associated with age and sex, and can therefore be used as a surrogate to assess hindbrain atrophy in a cross-sectional sample. Moreover, sex- and age-specific normal ranges may be needed to evaluate the PCF CI in clinical practice.

Adult↗

PubMed2005

In vivo tension sustained by fascial sling in pubovaginal sling surgery for female stress urinary incontinence.

PURPOSE: In pubovaginal sling surgery arguments have focused on selecting stronger sling materials, better suturing methods and superior fixation techniques. However, the grounding information prerequisite for these arguments is still lacking, ie the in vivo tension sustained by the sling. We designed this study to obtain this information. MATERIALS AND METHODS: A total of 10 female patients (mean age 65.4 years) underwent pubovaginal sling surgery while under epidural anesthesia. A strip of rectus fascia (2 x 6 cm) was isolated. Each end of the fascia was anchored with a 1-zero Prolene suture (Ethicon, Somerville, New Jersey). The fascial sling was placed over the proximal urethra. Both ends of the prolene (polypropylene) sutures were transferred to the lower abdominal incision and tied on each other. The fascial sling was adjusted just to touch the proximal urethra without elevating it. We hooked the tied polypropylene suture on a digital force gauge to measure the tension sustained by the fascial sling. Patients were instructed to cough, and the tension was measured at different bladder volumes (100, 200, 300, 400 ml) and in 2 positions (horizontal and operative table tilted head-up 20 degrees). Intravesical pressure was monitored with a pressure transducer to ensure adequate cough strength. We also investigated the in vitro length-tension relationship and tensile strength of 3 rectus fascia strips (0.5 x 6 cm) obtained from 3 of these patients. RESULTS: Mean tension +/- SEM sustained by the fascial sling during cough in the horizontal position was 0.046 +/- 0.004, 0.043 +/- 0.006, 0.0475 +/- 0.006 and 0.0485 +/- 0.007 kg at 100, 200, 300 and 400 ml bladder volume, respectively. Bladder volume did not statistically affect the sustained tension. The 20-degree head-up position also did not statistically change the tension sustained. In vitro study showed that the fascia strip could be stretched for a mean of 0.4 cm before sling tension began to increase. A mean load of 2.4 kg broke 0.5 x 6 cm strips. CONCLUSIONS: In the horizontal and mild tilting positions during an increase in intra-abdominal pressure, the fascial sling only sustains minor tension, which is far less than the maximal load needed to break fascial strips. The excellent elasticity of the fascia may dissipate the straining force and partly explains the measured small sustained tension.

Aged↗

PubMed2003

Opposing facilitatory and inhibitory modulation of glutamate release elicited by cAMP production in cerebrocortical nerve terminals (synaptosomes).

Activation of cAMP-protein kinase A (PKA) is widely reported to facilitate synaptic transmission. Here, we examined the presynaptic loci of PKA action using isolated nerve terminals (synaptosoms). The adenylyl cyclase (AC) activator, forskolin, failed to have any effect on 4-aminopyridine (4-AP)-evoked glutamate release, when added alone. However, in the presence of the alkylxanthine, IBMX, forskolin strongly facilitated glutamate release. This potentiation of release was blocked by the PKA inhibitors Rp-cAMPS and H7. Given that IBMX has dual activity, antagonizing adenosine receptors as well as inhibiting cAMP phosphodiesterase, we examined the effect of a selective adenosine A(1) receptor antagonist, 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) and RO20-1724, a specific phosphodiesterase inhibitor. Both unmasked the forskolin-mediated modulation of glutamate release. Conversely, the adenosine analogue, N(6)-cyclohexyladenosine (CHA), reversed the facilitation induced by forskolin+RO20-1724. Adenosine A(1) receptor activation, therefore, appears to curtail cAMP/PKA-induced potentiation of glutamate release. Looking at the targets for cAMP/PKA-mediated potentiation of glutamate release, while synaptosomal excitability was only marginally increased, basal and 4-AP-evoked-increases in [Ca(2+)](c) were substantially enhanced by forskolin+IBMX. Moreover, glutamate release elicited by Ca(2+)-ionophore (ionomycin)-induced Ca(2+)-entry was facilitated by forskolin+IBMX. cAMP/PKA-mediated facilitation of glutamate release may therefore involve modulation of Ca(2+)-entry, as well as downstream events controlling synaptic vesicle recruitment and exocytosis.

Animals↗

PubMed2003

Primary care physician attitudes concerning follow-up of abnormal test results and ambulatory decision support systems.

OBJECTIVES: Failures to follow-up abnormal test results are common in ambulatory care. Information systems could assist providers with abnormal test result tracking, yet little is known about primary care providers attitudes toward outpatient decision support systems. METHODS: A cross-sectional survey of 216 primary care physicians (PCPs) that utilize a single electronic medical record (EMR) without computer-based clinical decision support. RESULTS: The overall response rate was 65% (140/216). Less than one-third of the respondents were satisfied with their current system to manage abnormal laboratory, radiographs, Pap smear, or mammograms results. Only 15% of providers were satisfied with their system to notify patients of abnormal results. Over 90% of respondents felt automated systems to track abnormal test results would be useful. Seventy-nine percent of our respondents believed that they could comply better with guidelines through electronic clinical reminders. CONCLUSIONS: Most PCPs were not satisfied with their methods for tracking abnormal results. Respondents believed that clinical decision support systems (CDSS) would be useful and could improve their ability to track abnormal results.

Adult↗

PubMed2003

Quality of life and menopausal transition for middle-aged women on Kinmen island.

Although it seems reasonable to suggest that most women experience significant changes in quality of life (QOL) during the menopausal period, few researchers have quantified these changes. A total of 1497 women, aged 40-54 years and living on the island of Kinmen, were recruited for this survey. However, 137 were eliminated leaving 1360 for analysis. Women who used hormonal therapy or who had undergone surgically induced menopause were excluded. The subjects with incomplete data or who exhibited mental retardation or severe psychiatric disease were also eliminated. Univariate analysis demonstrated that, in general, QOL scores were poorer for perimenopausal and postmenopausal status. Comparing pre- and postmenopausal women, significant statistical differences were demonstrated for role limitations due to physical and emotional problems, even after adjusting for age, education level, body mass index, menarche, and chronic illness. A strong association was demonstrated between menopausal symptoms and premenstrual syndrome (PMS). Women with menopausal symptoms and PMS had significantly lower scores on all SF-36 dimensions. The results of this study suggest that poorer health status is experienced by peri- and postmenopausal women compared to premenopausal women.

Adult↗

PubMed2003

Targeting of post-ischemic cerebral endothelium in rat by liposomes bearing polyethylene glycol-coupled transferrin.

To achieve an efficient delivery targeting to post-ischemic cerebral vascular endothelium, PEG-liposome conjugated with transferrin (Tf) (Tf-PEG-liposome) was intravenously administered to the rats after 90 min of transient middle cerebral occlusion. The expression of Tf receptor (TfR) in the cerebral endothelium increased with a peak at 1 day after the reperfusion and returned to the control level by 6 days. The Tf-PEG fluorescence was marginally detectable in sham control brain, but remarkably increased with a peak at 2 days, showing about 70% of TfR positive vascular endothelium double-labeled with Tf-PEG. These results indicate that the Tf-PEG-liposome could be utilized as an efficient drug delivery tool to the brain after stroke.

Animals↗

PubMed2003

Functional improvement by electro-acupuncture after transient middle cerebral artery occlusion in rats.

Functional recovery by the application of electro-acupuncture (EA) on different acupoints was investigated using a transient middle cerebral artery occlusion (MCAO) model in rat. Acupoints were Baihui (D20) plus Renzhong (D26) (MCAO + D group), and Hanyan (G4), Xuanlu (G5), Xuanli (G6), plus Qubin (G7) (MCAP + G group). Animals with EA treatment showed significant functional improvements from 12 days after the reperfusion against those without EA treatment. Among EA treated groups, MCAO + G showed a more significant recovery than MCAO + D. Infarct volume revealed the significant reduction in the EA treated groups especially in MCAO + G at 30 days. Immunohistochemical study showed a remarkable induction of vascular endothelial growth factor (VEGF) in astrocytes of the peri-infarct area at 30 days, more in EA treated groups than in groups treated with MCAO alone. These results suggest that the acupoints applied in this study are effective for the functional recovery, and an enhanced expression of VEGF may play a certain role in recovery process after stroke.

Animals↗

PubMed2002

Enhanced phosphorylation of PTEN in rat brain after transient middle cerebral artery occlusion.

A phosphatase PTEN (phosphatase and tensin homologue deleted on chromosome 10) is a tumor suppressor gene that suppresses cell growth, inhibits cell migration, and induces apoptosis. Phosphorylated form of PTEN (p-PTEN) is a key survival factor relating PI3K-Akt pathway and their downstream effectors. A spatiotemporal profiles of PTEN and p-PTEN expression were immunohistochemically examined after 90 min of transient middle cerebral artery occlusion in rats. In the ischemic core, PTEN progressively decreased by 3 days, whereas a rapid but transient increase of p-PTEN was found with a peak at 1 h after the reperfusion. In contrast, in the ischemic penumbra, PTEN showed a minor change and a gradual but sustained p-PTEN expression was observed in the ischemic penumbra with a peak at 12 h. In addition, the balance of population among strongly, moderately, and weakly stained cells was different between the ischemic core and penumbra at their peak time points. These results suggest an important role of p-PTEN for cell survival after ischemia as an upstream regulator for PI3K-Akt.

Animals↗

PubMed2002

Neuropsychiatric symptoms of Alzheimer's disease differ in Chinese and American patients.

BACKGROUND: The prevalence of Alzheimer's disease is similar across ethnic groups. To our knowledge, no comparison of behavioral symptoms has been addressed. OBJECTIVE: This cross-sectional, retrospective, descriptive study compares neuropsychiatric symptoms of Chinese subjects with Alzheimer's disease (AD) at tertiary care centers in Taiwan and Hong Kong against Caucasian subjects in Los Angeles, California. We compared the frequency and severity of symptoms and caregiver responses to neuropsychiatric symptoms of AD using the Neuropsychiatric Inventory (NPI). We hypothesized that Chinese patients do not seek care unless they have high severity of neuropsychiatric symptoms and that Caucasian Americans do not wait for behavioral disturbances to develop before coming to medical attention. RESULTS: The Caucasian sample had the highest mean educational level and mildest Clinical Dementia Rating (CDR) scale distributions of all four groups. Older age and lower educational levels contributed to higher CDR scale scores, which in turn correlated with higher total NPI scores. Only one of the Chinese samples had a higher frequency of severe neuropsychiatric symptoms than the Caucasian sample. Chinese caregivers reported anxiety and delusions more frequently (58.1%) than Caucasians (37.3% and 39.6%; chi(2), p < 0.01 and p < 0.05, respectively). Caucasians reported appetite changes (47.3%) and apathy (59.2%) more frequently than the Chinese samples (chi(2), p < 0.05 and p < 0.01, respectively). Caregivers at all four centers were distressed by behaviors qualified as severe. CONCLUSION: We found support for our hypothesis, in that Chinese subjects presented during a more severe stage of dementia than American subjects, but the delay in seeking care could not be correlated with significant differences in neuropsychiatric profiles of the demented subjects. Other barriers to dementia care warrant investigation.

Aged↗

PubMed2002

Effect of neuropsychiatric symptoms of Alzheimer's disease on Chinese and American caregivers.

BACKGROUND: In Chinese culture, extended family support, acceptance of age-related cognitive changes and filial tradition of caring for elders may decrease caregiver burden and distress in the context of dementia. OBJECTIVE: To study cross-regional and cross-cultural differences in symptom-related caregiver distress due to the behavioral problems of Chinese and American patients with Alzheimer's disease. METHOD: Caregivers of patients with Alzheimer's disease at Taipei Veterans General Hospital, Taiwan (n = 89), Chinese University of Hong Kong (n = 31) and the UCLA Alzheimer's Disease Research Center, Los Angeles, California (n = 169) reported the neuropsychiatric symptoms of patients and their corresponding distress on the Neuropsychiatric Inventory. RESULT: Presence or absence of distress due to the neuropsychiatric symptoms of the patients with Alzheimer's disease was assessed. The three centers differed significantly in the proportions of caregivers with distress caused by depression (p < 0.05) and apathy (p < 0.001). UCLA had higher proportions of caregivers with depression-related distress than Taipei. UCLA caregivers were also more stressed by apathy than caregivers in Taipei and Hong Kong. Logistic regression further supported the findings that depression-related and apathy-related caregiver distress differed between Chinese and American caregivers (p < 0.05). CONCLUSIONS: The results were surprising, in that American and Chinese (Taipei and Hong Kong) caregivers exhibited similar distress or lack of distress in response to delusions, hallucinations, agitation, anxiety, euphoria, disinhibition, irritability, aberrant motor behavior, sleep and appetite symptoms of Alzheimer's disease patients. Chinese caregivers were less affected by depression and apathy in patients with Alzheimer's disease than Caucasian caregivers.

Aged↗

PubMed2002

Effects of cisapride on oesophageal transit of solids in patients with progressive systemic sclerosis.

In most patients with progressive systemic sclerosis (PSS) the oesophagus is affected. Reflux symptoms are most frequent, whilst dysphagia also occurs. Cisapride, a prokinetic agent, may enhance motility along the gastrointestinal tract. The effects of cisapride on oesophageal transit were evaluated in 12 PSS patient using a solid-phase radionuclide oesophageal transit study. Each PSS patient was given cisapride 10 mg or placebo orally three times a day in a random, double-blind, crossover fashion. The results show that cisapride does not seem to have any impact on oesophageal transit in patients with PSS.

Administration, Oral↗

PubMed2002

The level of IgA antibodies to human umbilical vein endothelial cells can be enhanced by TNF-alpha treatment in children with Henoch-Schönlein purpura.

Anti-endothelial cell antibodies (AECA) have been found to play an important role in many vascular disorders. In order to determine the presence of AECA in children with Henoch-Schönlein purpura (HSP), and to elucidate the pathogenic and clinical value of their measurement in this disease, AECA were detected by immunofluorescence staining and a human umbilical vein endothelial cell (HUVEC)-based enzyme-linked immunosorbent assay (ELISA) in 20 children with HSP, 10 children with juvenile rheumatoid arthritis (JRA) without vasculitis and 10 normal healthy children. Antibodies against another endothelial cells, human dermal microvascular endothelial cells (HMVEC-d) were also detected by cell-based ELISA. In some experiments, we compared the binding activity of antibodies to HUVEC with and without tumour necrosis factor-alpha (TNF-alpha) or interleukin-1 (IL-1) pretreatment. Patients with acute onset of HSP had higher serum levels of IgA antibodies, both against HUVEC and against HMVEC-d, than healthy controls (P = 0.001, P = 0.008, respectively). Forty-five per cent of patients had positive IgA AECA to HUVEC, and 35% had positive IgA AECA to HMVEC-d. The titres of IgA antibodies to HUVEC paralleled the disease activity. After TNF-alpha treatment, the values of IgA AECA to HUVEC in HSP patients were significantly increased (P = 0.02). For IgG and IgM AECA, there was no difference between HSP patients and controls (P = 0.51, P = 0.91). Ten JRA children without vasculitis had no detectable IgG, IgM or IgA AECA activity. The results of this study showed that children with HSP had IgA AECA, which were enhanced by TNF-alpha treatment. Although the role of these antibodies is not clear, IgA AECA provide another immunological clue for the understanding of HSP.

Adolescent↗

PubMed2002

A transcultural study of agitation in dementia.

Agitation is one of the most troublesome behaviors in demented patients. It is etiologically heterogeneous and has varied associated behaviors. To explore the transcultural differences in the manifestation of agitation, we evaluated 50 consecutive Alzheimer's disease (AD) patients in three countries (Taiwan, Italy, and the United States) using the Neuropsychiatric Inventory (NPI) and the Mini-Mental State Examination (MMSE). In a focused analysis, only patients with composite NPI scores > 2 for agitation were selected, with similar levels of disease severity as measured by the MMSE, from the three groups (n = 15 per group) to evaluate culturally specific correlates of agitation. Agitated Taiwanese had significantly more hallucinations than either Italian or American patients. Agitated Italian patients had significantly more apathy than both Taiwanese and American patients. Cultural factors may influence the manifestation of agitation more than a common underlying neuropathology. Management strategies targeting unique behavioral instigators of agitation may be specific for different ethnic groups.

Aged↗

PubMed2002

Enhanced expression of phospho-Akt by electro-acupuncture in normal rat brain.

Electro-acupuncture (EA) is an effective curative method for various diseases in oriental medicine. To investigate a detailed molecular mechanism of EA stimulation, an induction of phospho-Akt (p-Akt) was examined in normal adult rat brain after 60 min of EA with acupoints of Baihui (D20) and Renzhong (D26). In the sham control brain, strong neuronal p-Akt expression was found in ventral posterolateral thalamic nucleus (VPL) and medial habenular nuclei (MHb), but moderate to weak in cortex, caudate, CA1 sector and dentate gyrus of hippocampus, and ventral posteromedial thalamic nucleus. EA stimulation generally enhanced and sustained p-Akt expression for at least 24 h especially in the regions listed above, except VPL and MHb where no apparent change was found. Western blot analysis of p-Akt confirmed the enhanced signal intensity after EA at 8 and 24 h. These results suggest that the EA on D20 and D26 acupoints activates the survival Akt signal pathway, which may be maintaining the neural functions such as cell survival and memory formation in normal brain.

Animals↗

PubMed2001

The Kinmen women-health investigation (KIWI): a menopausal study of a population aged 40-54.

OBJECTIVES: This paper aims to report the methodology of a study of a cohort of middle-aged women in Taiwan, their age at menopause, and related factors and prevalence of menopausal symptoms, and to examine the relationships between symptoms and sociodemographic variables. METHODS: An epidemiological study of neuropsychological change during the menopausal transition among Chinese women aged 40-54 years old on the islet of Kinmen. RESULTS: Of a targeted population of 2256 individuals, 1497 (66%) participated in the study. The mean age at menarche was 15.6 years and that at menopause was 48 years. The hormone use rate at the time of study was 23% in surgical menopausal women, and 9% were past users. After excluding surgical menopausal and premenopausal women, 6% reported a current use of estrogen replacement therapy and 6% were past users. The most frequently reported discomforts for those women aged >45 were troubled sleep, backaches, and joint pain. Four symptom clusters: musculoskeletal, non-specific somatic complaints, urogenital, and vasomotor, were identified. After adjustment for age, the urogenital and vasomotor symptoms were significantly associated with menopausal status. CONCLUSIONS: The age at menopause did not differ much from Western studies, but the menopausal symptoms, especially the vasomotor symptoms, were much lower in our study population. Nevertheless, vasomotor symptoms were still significantly associated with menopausal status.

Adult↗