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W Lin

Publications and source records attributed to W Lin.

At least 127 records · Page 7Linked to original sources
PubMed1999

Quantitative magnetic resonance imaging in experimental hypercapnia: improvement in the relation between changes in brain R2 and the oxygen saturation of venous blood after correction for changes in cerebral blood volume.

Acute hypercapnia simultaneously induces increases in regional cerebral blood volume (rCBV) and the oxygen saturation of cerebral venous blood (Yv). Changes in both physiologic parameters may influence the changes in R2 (deltaR2) that can be measured in the brain with gradient echo magnetic resonance imaging. The authors examined the effect of incorporating independent measurements of the change in rCBV (deltarCBV) on the fidelity of the relation between deltaR2 and deltaYv in the setting of experimental hypercapnia. A two-dimensional T2-weighted gradient echo sequence was used to measure deltaR2 in the brain parenchyma of anesthetized rats in response to hypercapnia with respect to the control state. In parallel, estimates of rCBV were obtained using a three-dimensional steady-state approach in conjunction with a paramagnetic contrast agent during both control and hypercapnic states so that a deltarCBV could be calculated. Regional CBV values of 2.96 +/- 0.82% and 5.74 +/- 1.21% were obtained during the control and hypercapnic states, respectively, and linear relations between rCBV and CO2 tension in both arterial (r = 0.80) and jugular venous (r = 0.76) blood samples were obtained. When correlating deltaR2 directly with deltaYv, no clear relation was apparent, but a strong linear relation (r = 0.76) was observed when correction for deltarCBV was incorporated into the data analysis. These results are consistent with the current understanding of the mechanisms of blood oxygen level-dependent (BOLD) contrast and underscore the potential importance of taking into account deltarCBV when quantitative estimates of deltaYv from the "BOLD effect" are intended.

Animals↗
PubMed1999

Multiple system atrophy: a sporadic synucleinopathy.

Multiple system atrophy (MSA) is a sporadic neurodegenerative disease characterized clinically by varying degrees of Parkinsonism, cerebellar ataxia and autonomic dysfunction and pathologically by degeneration in the substantia nigra, putamen, olivary nucleus, pontine nuclei and cerebellum. In addition to selective neuronal loss, iron pigment accumulation and gliosis, myelin pathology is increasingly recognized. In affected white matter, myelin displays signs of degeneration and oligodendroglia contain argyrophilic inclusion bodies, so-called glial cytoplasmic inclusions (GCI). GCI are composed of 10-15-nm diameter coated filaments that are immunoreactive for ubiquitin and alpha-synuclein. Similar inclusions are occasionally found in neuronal cell bodies and cell processes in MSA. Given the presence of inclusion bodies composed of synuclein, it is reasonable to assume that biochemical alterations would be detected in synuclein in MSA and indeed this is the case. In MSA synuclein has biophysical properties that suggest increasing insolubility such as sedimentation in dense fractions in sucrose gradients and ready extraction into detergents and formic acid. Surprisingly, these biochemical modifications in synuclein are more widespread in the brain that the obvious pathology and suggest a fundamental molecular characteristic of the disorder. Similar neuronal, and less frequently glial, inclusions are detected in Lewy body disease, where there is also evidence for biophysical alterations in synuclein. Thus, MSA and LBD are both synucleinopathies, and they may comprise different poles of a disease spectrum that includes sporadic disorders as well as genetically determined disorders such as familial Lewy body Parkinsonism.

Humans↗
PubMed1999

Increased-contrast, high-spatial-resolution, diffusion-weighted, spin-echo, echo-planar imaging.

An insertable head gradient coil with a maximum gradient amplitude of 45 mT/m and a rise time of 150 musec along all three major axes was used to collect high-spatial-resolution, single-shot, spin-echo, echo-planar, diffusion-weighted magnetic resonance images with b values ranging from 0 to 2,200 sec/mm2. Improvements in spatial resolution allowed better visualization of large white matter tracts and their relation to adjacent anatomic structures. Excellent contrast and anatomic detail were revealed for most structures in the brain when a sufficient number of acquisitions were collected.

Adult↗
PubMed1999

Detection of changes in lung tissue properties with multiple-indicator dilution.

We evaluated the potential utility of a group of indicators, each of which targets a particular tissue property, as indicators in the multiple-indicator dilution method to detect and to identify abnormalities in lung tissue properties resulting from lung injury models. We measured the pulmonary venous outflow concentration vs. time curves of [14C]diazepam, 3HOH, [14C]phenylethylamine, and a vascular reference indicator following their bolus injection into the pulmonary artery of isolated perfused rabbit lungs under different experimental conditions, resulting in changes in the lung tissue composition. The conditions included granulomatous inflammation, induced by the intravenous injection of complete Freund's adjuvant (CFA), and intratracheal fluid instillation, each of which resulted in similar increases in lung wet weight. Each of these conditions resulted in a unique pattern among the concentration vs. time outflow curves of the indicators studied. The patterns were quantified by using mathematical models describing the pulmonary disposition of each of the indicators studied. A unique model parameter vector was obtained for each condition, demonstrating the ability to detect and to identify changes in lung tissue properties by using the appropriate group of indicators in the multiple-indicator dilution method. One change that was particularly interesting was a CFA-induced change in the disposition of diazepam, suggestive of a substantial increase in peripheral-type benzodiazepine receptors in the inflamed lungs.

Animals↗
PubMed1999

Pulmonary inflammation alters the lung disposition of lipophilic amine indicators.

Many lipophilic amine compounds are rapidly extracted from the blood on passage through the pulmonary circulation. The extent of their extraction in normal lungs depends on their physical-chemical properties, which affect their degree of ionization, lipophilicity, and propensity for interacting with blood and tissue constituents. The hypothesis of the present study was that changes in the tissue composition that occur during pulmonary inflammation would have a differential effect on the pulmonary extraction of lipophilic amines having different properties. If so, measurement of the extraction patterns for a group of lipophilic amines, having different physical-chemical properties, might provide a means for detecting and identifying lung tissue abnormalities. To evaluate this hypothesis, we measured the pulmonary extraction patterns for four lipophilic amines, [(14)C]diazepam, [(3)H]alfentanil, [(14)C]lidocaine, and [(14)C]codeine, along with two hydrophilic compounds, (3)HOH and [(14)C]phenylethylamine, after the bolus injection of these indicators into the pulmonary artery of isolated lungs from normal rabbits and from rabbits with pulmonary inflammation induced by an intravenous injection of complete Freund's adjuvant. The pulmonary extraction patterns, parameterized using a previously developed mathematical model, were, in fact, differentially altered by the inflammatory response. For example, the tissue sequestration rate, k(seq) (ml/s), per unit (3)HOH accessible extravascular lung water volume significantly increased for diazepam and lidocaine, but not for codeine and alfentanil. The results are consistent with the above hypothesis and suggest the potential for using lipophilic amines as indicators for detection and quantification of changes in lung tissue composition associated with lung injury and disease.

Algorithms↗
PubMed1999

Physiological evidence for ionotropic and metabotropic glutamate receptors in rat taste cells.

Monosodium glutamate (MSG) elicits a unique taste in humans called umami. Recent molecular studies suggest that glutamate receptors similar to those in brain are present in taste cells, but their precise role in taste transduction remains to be elucidated. We used giga-seal whole cell recording to examine the effects of MSG and glutamate receptor agonists on membrane properties of taste cells from rat fungiform papillae. MSG (1 mM) induced three subsets of responses in cells voltage-clamped at -80 mV: a decrease in holding current (subset I), an increase in holding current (subset II), and a biphasic response consisting of an increase, followed by a decrease in holding current (subset III). Most subset II glutamate responses were mimicked by the ionotropic glutamate receptor (iGluR) agonist N-methyl-D-aspartate (NMDA). The current was potentiated by glycine and was suppressed by the NMDA receptor antagonist D(-)-2-amino-5-phosphonopentanoic acid (AP5). The group III metabotropic glutamate receptor (mGluR) agonist L-2-amino-4-phosphonobutyric acid (L-AP4) usually mimicked the subset I glutamate response. This hyperpolarizing response was suppressed by the mGluR antagonist (RS)-alpha-cyclopropyl-4-phosphonophenylglycine (CPPG) and by 8-bromo-cAMP, suggesting a role for cAMP in the transduction pathway. In a small subset of taste cells, L-AP4 elicited an increase in holding current, resulting in taste cell depolarization under current clamp. Taken together, our results suggest that NMDA-like receptors and at least two types of group III mGluRs are present in taste receptor cells, and these may be coactivated by MSG. Further studies are required to determine which receptors are located on the apical membrane and how they contribute to the umami taste.

2-Amino-5-phosphonovalerate↗
PubMed1999

Hemispheric language dominance in children demonstrated by functional magnetic resonance imaging.

The objective of this study was to demonstrate hemispheric language dominance in normal children. Fifteen normal children were evaluated with functional magnetic resonance imaging (MRI) using an age-related silent word spelling paradigm. The data were analyzed with the cross-correlation method, and lateralization indices were calculated in language regions as determined by Talairach coordinates. Activation foci were detected in the left inferior frontal area and were strongly lateralized, with language lateralization indices of 0.74 +/- 0.21 (age 7-12 years, nine subjects), and 0.79 +/- 0.18 (13-18 years, six subjects). The indices were similar to those for adults (0.83 +/- 0.21, four subjects). Our study established that language is strongly lateralized to the left hemisphere in children as young as 7 years of age.

Adolescent↗
PubMed1999

An evaluation of the safety and immunogenicity of a five-component acellular pertussis, diphtheria, and tetanus toxoid vaccine (DTaP) when combined with a Haemophilus influenzae type b-tetanus toxoid conjugate vaccine (PRP-T) in Taiwanese infants.

OBJECTIVE: Immunologic interference particular to the Haemophilus influenzae type b (Hib) response has been observed with previous acellular pertussis-Hib combination vaccines. To test this hypothesis a clinical trial to assess the safety and immunogenicity of a five-component (pertussis toxoid [PT], filamentous hemagglutinin [FHA], pertactin [PRN], and fimbriae 2 and 3 [FIM]), pertussis vaccine combined with diphtheria and tetanus toxoids (DTaP) when given simultaneously with a lyophilized Hib-tetanus toxoid conjugate vaccine (PRP-T) in infants at 2, 4, 6, and 18 months of age was conducted. The study compared two methods of administration: both vaccines combined in a single syringe and administered as a single injection, or both vaccines administered concurrently but at separate sites of injection. METHODS: Healthy 2-month-old infants were enrolled at the National Taiwan University Hospital. DTaP, PRP-T, and oral poliomyelitis vaccine (OPV) were given at 2, 4, 6, and 18 months. Reaction information was collected by telephone 2 days after each vaccination. Serum was collected at 2, 6, 7, 18, and 19 months of age. RESULTS: One hundred thirty-five healthy infants were enrolled in Taiwan, of which 127 (94%) completed the 18-month booster: 68 received the combined vaccine and 67 the separate vaccines. All vaccines were well tolerated. No differences in rates of local and systemic reactions were seen between the two methods of administration. No serious adverse events were reported. Serologic responses were comparable between the groups. Pertussis responses (enzyme-liked immunoabsorbant assay units [EU]/mL) at 7 months were, for combined versus separate, PT (131 vs 105), FHA (116 vs 116), PRN (100 vs 77), and FIM (922 vs 702). At 19 months, pertussis results were, for combined versus separate, PT (216 vs 182), FHA (203 vs 200), PRN (263 vs 197), and FIM (892 vs 732). Only the 7-month PT response in the combined group was significantly higher (combined 131 EU/mL vs separate 105 EU/mL). After the third dose (age 6 months), all subjects achieved serologic serum antibody levels indicative of protection against Hib, diphtheria, tetanus, and poliovirus types 1, 2, and 3. In fact, 96% of children had anti-PRP levels indicative of protection (>/=0.15 microgram/mL) against Hib after only two doses. At 7 months, anti-PRP geometric mean titer values were 11.8 micrograms/mL in the combined group compared with 13.0 micrograms/mL in the separate group. The anti-PRP geometric mean titers after the 18-month booster were 58.5 micrograms/mL in the combined group versus 55.3 micrograms/mL in the separate group. CONCLUSION: The five-component DTaP vaccine may be combined with PRP-T vaccine without clinically significant immunologic interaction when given in a 2-, 4-, 6-, and 18-month schedule.

Diphtheria↗
PubMed1999

Desensitization and resensitization of lutropin receptors expressed in transfected Y-1 adrenal cells.

Stimulation of gonadal cells by lutropins such as human chorionic gonadotropin (hCG) is often transient and followed by down-regulation and/or desensitization of lutropin receptors (LHR). Here we describe desensitization/resensitization of LHR in Y-1 adrenal cell lines (termed Y-1L) expressing a rat cDNA lacking most 5' and 3' LHR untranslated regions under the control of a metallothionein promoter. Using a simple morphological assay in which stimulated cells are round and unstimulated cells are flat, we identified clones that rounded and remained round and others that became insensitive to lutropin stimulation and reverted to their flat appearance within 2-4 h. Flattened cells were insensitive to further hormonal stimulation but rounded after treatments with cholera toxin, forskolin, or cyclic AMP, showing that loss of responsiveness was associated with an early step in signal transduction, not loss of rounding potential. Removing the lutropin stimulus for at least 90-120 min reversed hormone insensitivity, even in the presence of the protein synthesis inhibitor puromycin. The number of surface bound receptors did not change during a cycle of rounding/flattening and hCG bound to rounded or flattened cells was replaced equally by radioiodinated hCG during incubations at 4 degrees C. Thus, desensitization/resensitization of LHR in Y-1L cells occurred in the absence of new receptor synthesis, receptor degradation, or receptor recycling. These observations suggest that LHR desensitization/resensitization in Y-1L cells was closely coupled to receptor occupancy and that this cell line may be useful for identifying factors that modulate the activities of occupied receptors.

Adrenal Glands↗
PubMed1999

Echoplanar diffusion-weighted imaging in neonates and infants with suspected hypoxic-ischemic injury: correlation with patient outcome.

OBJECTIVE: Our objective was to examine the effectiveness of echoplanar diffusion-weighted (DW) imaging in detecting CNS ischemia in neonates and infants and to determine how well the imaging findings using this technique correlate with short-term neurologic deficit. MATERIALS AND METHODS: Echoplanar DW images, turbo T2-weighted images, and fluid-attenuated inversion recovery (FLAIR) sequences were obtained in a clinically defined cohort of 26 consecutive neonates and infants with suspected hypoxic-ischemic injury. Echoplanar DW imaging was performed with the diffusion gradient in the slice-select direction: b value, 1200 sec/mm2; matrix, 128 x 128, interpolated to 256 x 256. Four scans (4 sec per scan) were obtained and averaged to optimize the signal-to-noise ratio. Most patients were not sedated (n = 19). Abnormalities seen on DW imaging were correlated with clinical findings at short-term follow-up and compared with findings on FLAIR and turbo T2-weighted images. RESULTS: Short-term clinical follow-up showed neurologic deficit in 10 (83%) of 12 patients with DW images with abnormal findings, and no neurologic sequelae in 12 (86%) of 14 patients with DW images with normal findings. Echoplanar DW images revealed a greater extent of and a larger number of abnormalities compared with FLAIR or turbo T2-weighted images in 11 (92%) of 12 patients with DW images with abnormal findings. CONCLUSION: Echoplanar DW imaging reveals abnormalities poorly depicted on turbo T2-weighted and FLAIR images in neonates and infants with clinically suspected hypoxic-ischemic injury. DW imaging may be able to identify which patients are likely to develop at least short-term neurologic deficits and may afford the best early evaluation of short-term neurologic prognosis in these patients.

Brain↗
PubMed1999

MR high-resolution blood oxygenation level-dependent venography of occult (low-flow) vascular lesions.

A new technique for detecting vascular malformations, high-resolution BOLD venography (HRBV), is described. This technique relies on the BOLD principle for detecting deoxygenated blood in low-flow malformations. HRBV images are acquired using a modified 3D gradient-echo with voxel volumes of 0.5 x 0.5 x 2 mm3. The magnitude data are masked with the phase images to enhance visibility of the venous structures and are displayed using the minimum intensity projection. Preliminary results for 10 patients show that HRBV is more sensitive in detecting cavernomas than is T2-weighted imaging, and lesions that are presumed to be telangiectasias are detected only with this technique.

Brain↗
PubMed1999

Congenital choledochal cyst with pancreatitis.

OBJECTIVE: To understand the relationship among congenital choledochal cyst, anomalous junction of pancreaticobiliary duct (AJPBD) and pancreatitis. METHODS: 25 children with choledochal cyst treated in our hospital were included in this study. Their ages ranged from 2 months to 14 years. Intraoperative cholangiography was performed in 24 children. Pancreatic samples obtained from the head and body of the pancreas at operation were observed under light and electron microscope. Serum amylase was analyzed one week before and after operation respectively. Bile amylase in the cyst and gallbladder was measured at operation. RESULTS: The incidence of AJPBD was 70%. Inflammatory cell infiltration and fibrous hyperplasia were seen in the pancreatic specimens of 5 children, of whom 4 had AJPBD. No ultrastructural changes were found in 2 children without AJPBD, while different changes were seen in 6 with AJPBD, including those showing no pathological changes under light microscope. All the changes became more severe as the age of the patient increased. The bile and serum amylase levels were higher in children with AJPBD than those without AJPBD (P < 0.05). CONCLUSION: Congenital choledochal cyst has a close relationship with AJPBD and pancreatitis. Pancreatic pathological changes have a long and chronic course from ultrastructural changes to macroscopic changes for the developing of pancreatitis.

Adolescent↗
PubMed1999

[Diagnosis and surgical treatment of idiopathic slow transit constipation].

OBJECTIVE: To investigate the pathogenesis, the diagnostic criteria, and the therapeutic method of idiopathic slow transit constipation. METHODS: History recording, bowel transit, anorectal dynamic, electromyography of the pelvic floor and defecography were performed before subtotal or total colectomy for severe constipation resistant to conservative treatment. RESULTS: The natural stool frequency was decreased and the time of bowel transit was delayed. The rectal sensation and the ability to reflect inhibition of the pelvic floor when attempting to defecate were damaged significantly compared with normal controls. pathological findings showed that the argyrophilic neurons in the myentenic and submucous plexus reduced quantitatively. All the patients were followed up for an average of 32.2 months. Satisfactory functional outcome was obtained in 91.8% of the patients receiving the operation. CONCLUSIONS: The severe damage colon transit function is due to the impairement of the myentenic and submucous plexus of the colon. It causes vary. The diagnosis of the disease is dependent on the typical clinic features and the bowel transit test. The symptoms of constipation could be relieved effectively by removal of the pathologic colon.

Adolescent↗
PubMed1999

[Antagonistic effects of metallothionein on genetic damage caused by gamma-rays and mitomycin C].

OBJECTIVE: To study the antagonistic effects of metallothionein (Zn-MT)on genetic damage caused by gamma-rays and mitomycin C (MMC) in the liver of rabbits. METHODS: Micronucleus test and DNA strand breaks were determined in vitro and in vivo with single-cell gel electrophoresis assay to observe the effects of Zn-MT on the micronucleus formation and cleavage of DNA chain before and after gamma-rays radiation and MMC treatment. RESULTS: A dose of 664 microg/kg of Zn-MT could inhibit micronucleus formation in the bone marrow of the mice induced by 5 Gy gamma-rays radiation (P < 0.05). Concentrations of 10 and 50 microg/ml Zn-MT could antagonize the increase in bimicronucleus frequency in g12 cells induced by 1 and 3 Gy gamma-rays radiation and 0.3 microg/ml MMC treatment (P < 0.05 or P < 0.01). A dose of 50 microg/ml Zn-MT could reduce the DNA single strand breaks caused by 1 Gy gamma-rays radiation, but without statistical significance (P > 0.05). CONCLUSION: Zn-MT could antagonize the genetic damage to certain extent in the liver of the rabbits caused by gamma-rays radiation and MMC treatment.

Animals↗
PubMed1999

[Studies on DNA single strand breaks induced by sodium nitroprusside-nitric oxide donor].

OBJECTIVE: To study the effect of sodium nitroprusside (SNP), a nitric oxide (NO) donor, on DNA single strand breaks (SSBs). METHODS: A modified method was used to isolate and prepare the single cell suspension from the organs of mice. Alkaline single-cell gel electrophoresis (SCGE) was performed to examine DNA damage of the cells treated by SNP in vivo and in vitro. RESULTS: Treatment with 0.5 - 2.0 micromol/ml of SNP with S(9) for 1 h induced a concentration-dependent increase in DNA SSBs in g12 cells. Significant increase in DNA migration and comet frequency in the spleen, thymus and peritoneal macrophage were induced after intraperitoneal injection of SNP at a dose of 0.67 - 6.0 mg/kg. No obvious increase in DNA single strand breaks was observed in the liver, kidney and lung of the mice with same treatment. CONCLUSION: DNA SSBs could be induced by NO in some cells in vivo and in vitro. There was difference in sensitivity of various organs in the mice to NO. Cells of spleen and thymus and macrophage may be the important target cells of NO.

Animals↗
PubMed1999

[Expression and significance of basic fibroblast growth factor in ovarian epithelial neoplasm].

OBJECTIVE: To determine the effect of basic fibroblast growth factor (bFGF) on the biological behaviour of ovarian epithelial neoplasm. METHODS: Ten cases of normal ovarian tissues and eighty cases of ovarian epithelial tumor tissues were detected by immunohistochemical methods. Mias-2000 Picture Analysis System was used to study the relationship of bFGF expression intensity and microvessel count, FIGO stage, pathological grade and classification of ovarian epithelial neoplasm. RESULTS: 1. Expression of bFGF was mainly in cytoplasm and nucleus in several cells of borderline and malignant tumor. 2. The expression intensity of bFGF was closely related to the malignant degree of ovarian epithelial neoplasm. The density of bFGF expression was (3.35 +/- 3.52)% in normal ovarian epithelium, (19.25 +/- 21.73)% in benign tumor, (33.78 +/- 10.86)% in borderline tumor and (48.18 +/- 12.93)% in malignant tumor. The results indicated that bFGF might play an important role in carcinogenesis of ovarian epithelial neoplasm. 3. The expression intensity of bFGF was increased with the FIGO stage of ovarian tumor. 4. The expression intensity of bFGF was increased accompanying with the decrease of differentiation degree in ovian neoplasm. 5. In borderline tumor, expression intensity of bFGF in serous cystadenoma was significantly higher than in mucinous cystadenoma, which indicated bFGF might be an important factor in canceration of ovarian epithelial neoplasm. CONCLUSION: bFGF may play important roles in carcinogenesis, development, invasion and metastasis of ovarian epithelial neoplasm.

Cystadenoma, Mucinous↗
PubMed1999

[A gas chromatographic method to decrease the detection limit of trace benzene in CS2 extract].

A method to decrease the detection limit of trace benzene in CS2 extract from coastal water by gas chromatography has been studied. A direct injection port (Shimadzu WBI-17) and a 2 m x 2 mm i.d. column packed with Chromosorb W(AW-DMCS) coated with 10% SE-30 was used. It is simpler and has low detection limit, small sample amount and high repeatability. The experiment showed that the trace water in the organic phase and the too small purge flow of the direct injection port could cause serious tailing of CS2 peak. There was an optimum value of the purge flow (purge flow/total flow = 5%). The minimum detectable limit of benzene was 4 micrograms/L. The repeatability (RSD) was better than 6% and the average recovery was 96.7%.

Benzene↗