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Biomedical subjects

S T Lin

Publications and source records attributed to S T Lin.

At least 19 recordsLinked to original sources
PubMed2006

Light-enhanced electro-optic spectral tuning in annealed proton-exchanged periodically poled lithium niobate channel waveguides.

We report the observation of light-enhanced electro-optic spectral tuning in annealed proton-exchanged, asymmetric domain-duty-cycle periodically poled lithium niobate (PPLN) channel waveguides for second-harmonic generation. The spectral tuning rate was increased rapidly from 0.07 nm/(kV/mm) to a saturated value of 0.32 nm/(kV/mm) in a 30%/70% domain-duty-cycle PPLN waveguide when the fundamental pump power near 1534 nm was increased from 0.6 to 46 mW. The second-harmonic laser power at 767 nm was identified to be the source enhancing the spectral tuning.

Journal Article↗
PubMed2005

Enhanced terahertz-wave parametric generation and oscillation in lithium niobate waveguides at terahertz frequencies.

We observed parametric-generation efficiency of 1.61% from 1064 to 1071 nm and at 162 microm in a 0.5 mm thick, 45 mm long z-cut congruent lithium niobate waveguide with a pump energy of 2.2 mJ and a pump pulse width of 5.8 ns. We also measured an ultralow-threshold intensity of 70 MW/cm2 for a 1064 nm pumped parametric oscillator resonating at 1071 nm and emitting at 162 microm with a 1 mm thick, 45 mm long lithium niobate waveguide.

Journal Article↗
PubMed2003

Limit on the electron neutrino magnetic moment from the kuo-sheng reactor neutrino experiment.

A search of neutrino magnetic moment was carried out at the Kuo-Sheng Nuclear Power Station at a distance of 28 m from the 2.9 GW reactor core. With a high purity germanium detector of mass 1.06 kg surrounded by scintillating NaI(Tl) and CsI(Tl) crystals as anti-Compton detectors, a detection threshold of 5 keV and a background level of 1 kg(-1) keV(-1) day(-1) at 12-60 keV were achieved. Based on 4712 and 1250 h of reactor ON and OFF data, respectively, the limit on the neutrino magnetic moment of mu(nu;(e))<1.3x10(-10)mu(B) at 90% confidence level was derived. An indirect bound of the nu;(e) radiative lifetime of m(3)(nu)tau(nu)>2.8x10(18) eV(3) s can be inferred.

Journal Article↗
PubMed2002

Molecular cloning and sequence analysis of full-length cDNAs encoding new group of Cyn d 1 isoallergens.

BACKGROUND: Cyn d 1, the major allergen of Bermuda grass pollen, contains some acidic/basic isoforms. The N-terminal amino acid sequences of some acidic Cyn d 1 isoforms were found to be different from those of Cyn d 1 cDNA clones identified previously. METHODS: A predicted 17-meric oligonucleotide probe was designed to fish the unidentified isoallergen cDNAs out of BGP cDNA library. The reactive clones were isolated and verified by sequencing. Two of them were expressed in the yeast Pichia pastoris to obtain recombinant Cyn d 1 proteins. RESULTS: All four cDNA clones encode the full-length Cyn d 1 with mature proteins of 244 amino acid residues. A 97-99% identity was found among the deduced amino acids of these four clones while an 86% identity was elicited between the four clones and the ones previously identified. The predicted isoelectric focusing (pI) values of the newly identified Cyn d 1s are acidic while pIs of the previously identified Cyn d 1s are basic. The two recombinant acidic Cyn d 1 proteins possess the epitopes recognized by mouse and rabbit polyclonal anti-Cyn d 1 antibodies, and have human IgE-binding capacity as revealed by immunodot assay. CONCLUSIONS: The present study identified full-length cDNAs encoding new isoallergens of Cyn d 1, and separated Cyn d 1 gene into an acidic group and a basic group.

Allergens↗
PubMed1999

Disinfection of hospital waste sludge using hypochlorite and chlorine dioxide.

Hypochlorite and chlorine dioxide were used to disinfect hospital waste-water sludge. Their abilities to inactivate pathogenic micro-organisms were compared. Reductions in indigenous coliform organisms and Pseudomonas aeruginosa were estimated. The results indicate that hypochlorite is a better disinfectant than chlorine dioxide for coliforms. Higher disinfection efficiency was obtained by treating a lower concentration of sludge. In addition, a higher agitation speed gave a higher disinfection efficiency with hypochlorite. The disinfection efficiencies of both disinfectants were higher against settled sludge than against thickened sludge. Therefore, it is recommended that disinfection should be performed on settled sludge rather than in a thickening tank.

Chlorine Compounds↗
PubMed1999

[Stress and dietary salt intake in the pathogenesis of hypertension: role of the renal and sympathetic nervous system].

Using the methods of electrophysiology, biochemistry, radioimmunoassay, and electron microscopy, changes of sympathetic nervous system and renal function in hypertensive SD rats induced by stress and high-salt intake were investigated. The results are as follows: (1) Renal plasma flow (RPF) and urinary sodium excretion obviously increased in salt-loading rats. Stress could result in marked reduction of RPF. (2) Electron micrography showed a dramatic increase in cell and mitochondrial volume in the proximal and distal convoluted tubules of high-salt diet rats. After stress of two weeks, the cells of the tubule became atrophic and mitochondrial volume decreased. (3) The same recovery from the declining renal cortical Na-K-ATPase activity in high-salt diet rats could be observed by maintained stress. (4) Low frequency (0.2-0.9 Hz) of BP variability was higher in stress rats as compared to control. (5) Both plasma renin activity (PRA) and angiotensin II (ANG II) levels increased in stress rats, but the decrease in high-salt diet rats gradually reached the high level of the former in two weeks. (6) Increase of BP, fall in RPF, or augment in PRA and ANG II were not observed in stress rats subjected to bilateral renal denervation. The above results indicate that the renal mechanism mediated by increased renal sympathetic nervous system plays an important role in stress- and salt-induced hypertension pathogenesis.

Animals↗
PubMed1998

Low intensities and 1.3 ratio produce distortion product otoacoustic emissions which are larger in heterozygous (+/dn) than homozygous (+/+) mice.

The f2/f1 frequency ratio of 1.3 in combination with stimulus levels of L1/L2 = 50/60 and 50/50 dB SPL produced a higher level of distortion product otoacoustic emissions (DPOAE) in the heterozygous (+/dn) mice than in the homozygous (+/+) mice. These results suggest that the dn gene carriers have a unique cochlear trait which may be related to the dn gene locus and expressed via a frequency- and intensity-dependent DPOAE function.

Acoustic Stimulation↗
PubMed1998

Quantification of pathogenic micro-organisms in the sludge from treated hospital wastewater.

The sludge from hospital waste treatment facilities is a potential source of infectious organisms. The average numbers of micro-organisms in the sludge of hospital wastewater in Taiwan were as follows: total count 8.1 x 10(7) cfu g-1 (dry weight of sludge), and 1.4 x 10(6), 3.6 x 10(5), 1.6 x 10(5), 2.2 x 10(5) and 5.5 x 10(4) cfu g-1 (dry weight of sludge) for total coliforms, faecal coliforms, faecal streptococci, Pseudomonas aeruginosa and Salmonella spp., respectively. Salmonella spp. were detected in 37% (10 of 27) of the sludges from hospital wastewaters. Therefore, the treatment of such sludge to reduce pathogenic micro-organisms should be considered.

Escherichia coli↗
PubMed1996

Modulatory effects of polycyclic aromatic hydrocarbons on the mutagenicity of 1-nitropyrene: a structure-activity relationship study.

Benzo[a]pyrene (B[a]P) is able to inhibit the mutagenicity of 1-nitropyrene (1-NP) through the reduction of nitroreductase activity and formation of adducts with DNA. The relationships between the chemical structure of 9 polycyclic aromatic hydrocarbons (PAHs) and antagonistic effects on the 1-NP-induced mutation were evaluated by the binary mixtures of 1-NP and PAHs with Salmonella typhimurium TA98 in the absence of S9 mix. Remarkably different antagonistic effects of 9 PAHs on the mutagenicity of 1-NP were observed. Among the tested PAHs, coronene demonstrates the most antagonistic potential followed by benzo[g,h,i]perylene (B[g,h,i]P), benzo[e]pyrene (B[e]P), dibenzo[a,h]pyrene (DB[a,h]P), benzo[a]pyrene (B[a]P) and pyrene. Naphthalene, anthracene, and chrysene had only minor inhibitory activity on the 1-NP mutagenicity. The modifying effects of PAHs on the nitroreductase activity of TA98 strains in the presence of 1-NP were further examined from the production of 1-AP. The statistical analytical data showed that the inhibitory effect of PAHs on the mutagenicity of 1-NP significantly correlated with their effects on the nitroreductase activity (r = -0.69, p < 0.05). In addition, the formation of 1-NP-DNA adducts of the binary mixtures of 1-NP and PAH was determined by the 32P-postlabeling method. The results indicated that the modulatory effects of PAHs on the formation of 1-NP-DNA adducts were correlated well with their antagonistic activity (r = -0.91, P < 0.01). From the above results, the relationships between the chemical structure of PAHs and the antagonistic effects on the 1-NP mutagenicity were revealed by the surface area and electronic parameters of PAHs. The planar molecular area of PAHs was more convincingly correlated with the antagonistic effect on the mutagenicity of 1-NP (r = -0.81, p < 0.01) than that with the difference in energy, delta E, between EHOMO and ELUMO (r = 0.69, p < 0.05). According to the above, two possible mechanisms are involved in the interactive effect of the binary mixtures: (1) a higher binding affinity with nitroreductase for PAHs having a large planar surface area; and (2) a high energy of interaction between 1-NP and PAHs with a low delta E might decrease the nitroreductive capability.

Antimutagenic Agents↗
PubMed1995

Unexplained gradual-onset Q wave patterns. A case series from the Framingham Study.

Original cohort members of the Framingham Study were studied to determine prognosis associated with unexplained (gradual-onset) Q wave patterns detected on routine electrocardiograms (ECGs). Biennial ECGs were obtained on subjects beginning in 1948. The index ECG was read independently and then serially in relation to all previous tracings for evidence of myocardial infarction. Proportional hazards modeling was used to assess the risk for outcomes in those with unexplained (gradual-onset) Q wave patterns compared with subjects with unrecognized myocardial infarcts (abrupt-onset Q waves) and compared with referent subjects. Unexplained Q wave patterns developed in 53 men and 39 women. Subjects with unexplained Q wave patterns had less than 40% of the risk for myocardial infarction or coronary death as compared with those with unrecognized myocardial infarction after adjusting for risk factors (hazard ratio, 0.38; 95% confidence interval, 0.19, 0.78; P = .008) and a trend toward a lower risk for overall mortality (adjusted hazard ratio, 0.73; 95% confidence interval, 0.46, 1.16; P = .18). Risks for myocardial infarction or coronary death and overall mortality were similar in subjects with unexplained Q wave patterns and referent subjects in the fully adjusted models. Detection of prominent Q waves on an ECG requires comparison with prior tracings to differentiate the unexplained Q wave pattern from the unrecognized infarct, conditions that have significantly different prognostic implications.

Aged↗
PubMed1994

Characterization of the mutagen 2-amino-3-methylimidazo[4,5-f]quinoline prepared from a 2-methylpyridine/creatinine/acetylformaldehyde model system.

A mixture of 2-methylpyridine, creatinine and aldehydes was heated in diethylene glycol containing 5% water for 1 h at 140 degrees C. The mutagenic compounds were purified by XAD-2 column chromatography, acid/base partition, blue cotton treatment, thin layer chromatography and HPLC. The active substances purified from each step were monitored by their mutagenicity with Salmonella typhimurium TA98 in the presence of S9 mix. Among the mutagens collected, 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) was isolated from HPLC, and was identified by its UV and mass spectrum using a photodiode array detector and mass spectrometry. Our findings appear to be the first experimental evidence to substantiate the hypothetical pathway for the formation of IQ mutagens from a heated model system consisting of a pyridine or pyrazine derivative, an aldehyde and creatinine or creatine.

Biotransformation↗
PubMed1994

Development of bioabsorbable glass fibres.

Calcium-iron phosphate glasses with an iron oxide content ranging from 5 wt.% to 22 wt.% were prepared to investigate the effect of iron oxide on the properties of the glass. It was found that the dissolution rate, the fibre strength and the glass transition temperature were strongly affected by iron oxide. The glass dissolution rate exhibited a 50-fold reduction while the fibre strength doubled when the iron oxide content was increased from 5 wt.% to 22 wt.%. The phosphate glass containing 22 wt.% of iron oxide had a dissolution rate of about 5 micrograms/(cm2 day). The fibres drawn from this glass also exhibited the highest tensile strength over 1000 MPa. A cortical bone plug method was used to assess the biocompatibility of the glasses with the hard and soft tissues. The tissues surrounding the samples showed no inflammation at 9 wk.

Animals↗
PubMed1993

Cranial computed tomography in children with acute lymphoblastic leukemia after prophylactic treatment with cranial radiation therapy and intrathecal methotrexate.

BACKGROUND AND METHODS: Thirty-one children with acute lymphoblastic leukemia (ALL) who had received cranial radiation therapy (CrRT) and five concomitant doses of intrathecal methotrexate (IT MTX) for central nervous system prophylaxis (CNSP) and who had an event-free survival exceeding 5 years had cranial computed tomography (Cr CT) examination. The fractional dose for 21 of them was 1.5 Gy. The interval between the completion of CNSP and the time of Cr CT ranged from 5 to 8.5 years, with a median of 5 years 2 months. RESULTS: Unlike the previous reports in the literature that 9-77% of children with ALL who had received Cr RT 18 Gy and IT MTX as CNSP had CT scan abnormalities, in this study no patient had CT scan abnormalities. CONCLUSIONS: Our results might be attributable to the fractional dose of Cr RT being adequate, the IT chemotherapy being suitable, and the systemic chemotherapy not being intensive.

Brain↗
PubMed1993

Health status of patients with childhood acute lymphoblastic leukemia in continuous complete remission for over five years. The Taiwan Children's Cancer Study Group.

Ninety-seven patients with childhood acute lymphoblastic leukemia (ALL) have achieved complete continuous first remission for more than five years. They were treated by Taiwan Children's Cancer Study Group protocol 821 or protocol 842. Their present health status was evaluated using blood counts, immunology, a psychiatric analysis and growth parameters. Hemoglobin and platelet counts rose quickly to the normal range after complete remission was achieved, then remained at low normal throughout the course. The leukocyte counts responded immediately to chemotherapy, usually recovering to about 5,000/uL, then gradually increasing after completion of chemotherapy. The absolute neutrophil counts were at a low normal level during chemotherapy, then gradually recovered to the normal level after chemotherapy was completed. Immunologic investigation after completion of chemotherapy showed that the subsets of lymphocytes were nearly all in the normal range for the 38 patients tested. On the other hand, in 17 patients tested for T-cell function, it was found that 29.4% had low natural killer (NK) cell cytotoxicity, 11.8% had an abnormal phytohemagglutinin (PHA) test and all had abnormally low IL-2 production (in vitro). There were 29 patients who had psychiatric analyses; the full IQ was borderline in 10.3%. The primary or middle school academic scores of 55 patients were reported; 15% of them belonged to the lower one-third of the class. Height was assessed by the standard deviation score from the mean for 58 patients. The differences were statistically insignificant; however, there were six patients whose growth curves crossed over their initial percentile line.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1993

Hematuria due to nutcracker phenomenon of left renal vein: report of a case.

The nutcracker phenomenon refers to compression of the left renal vein between the aorta and the superior mesenteric artery, which leads to painless intermittent gross hematuria. An 11-year-old girl presented with a two-year history of recurrent painless hematuria. Physical examination and routine laboratory examinations were noncontributory. Renal ultrasonographic study, selective left renal angiography and retrograde left renal venography showed evidence of compression of the left renal vein where it crossed between the aorta and the superior mesenteric artery. A needle biopsy of the right kidney revealed no abnormal histologic change. These results led to a diagnosis of the nutcracker phenomenon; to the best of our knowledge, this may be the first case reported in Taiwan. Herein, we present our experience with this case and discuss the diagnostic options.

Angiography, Digital Subtraction↗
PubMed1993

Treatment of childhood acute lymphoblastic leukemia with protocol TCL-842 in Taiwan: the Taiwan Children's Cancer Study Group.

From March 1984 to May 1988, 212 children with acute lymphoblastic leukemia were enrolled on Protocol TCL-842. In all, 68 patients were classified as standard risk (SR), 56 as intermediate risk (IR), and 88 as high risk (HR) groups. Remission induction for all three groups consisted of vincristine (VCR), prednisolone (PRED) and L-asparaginase (L-Asp). One consolidation course with cyclophosphamide (CP) and cytarabine (AraC) was used for the SR and IR groups, and two courses were given to patients in the HR group. Central nervous system prophylaxis was randomized using either cranial irradiation 18 Gy + 5 intrathecal methotrexate (IT MTX) or triple IT with maintenance. Reinforcement cycles were employed periodically during maintenance therapy (basically 6-mercaptopurine+MTX) and varied among the three groups. Four-week oral PRED every 16 weeks was the sole reinforcement agent for SR. Two-week VCR+dexamethasone (DEX)+adriamycin CP cycles were used to reinforce IR and HR at different intervals. Five third-form cycles with VCR+DEX+AraC were used only for HR. Treatment was discontinued after three years in patients who achieved continuous complete remissions (CCR). Eight patients died during the induction phase and eight failed to achieve complete remission (CR). The CR rate for SR was 97%, for IR was 98% and for HR was 83.3%; the overall rate was 91.8%. As of 30 June 1991, 33 patients had dropped out, 12 had died during remission, and 52 had relapsed. Twenty-eight SR, 26 IR, and 29 HR patients remained in CCR with a median follow-up duration of 66 months (38-88 months).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Transient myeloproliferative disorder and acute myeloid leukemia: study of six neonatal cases with long-term follow-up.

Six neonates with hematological and clinical pictures indistinguishable from acute myeloid leukemia were studied. Two patients had Down syndrome and three others had either +21 or i(21q) chromosomal abnormalities in their blood cells at presentation. Granulocyte-macrophage colony-forming unit assays performed in bone marrow and peripheral blood mononuclear cells revealed abnormal growth patterns in two patients; both died of progressive disease of acute myeloid leukemia. All the other four neonates with normal in vitro cell growth pattern had spontaneous remission within 7 months. Of these four patients, one remains well and in remission for 8 years and the other three developed acute myeloid leukemia at the ages of 15, 32 and 19 months, respectively. We conclude that the in vitro cell growth pattern is helpful to distinguish transient myeloproliferative disorder from congenital acute myeloid leukemia and that patients with the former condition are at risk to develop acute myeloid leukemia subsequently.

Acute Disease↗