Telangiectatic pacemaker erythema.
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Aged↗
Biomedical subjects
Y C Lin
Publications and source records attributed to Y C Lin.
Effects of seasonal variation in precipitation on estimation of non-point source pollution.
The extent of nonpoint source pollution (NPSP) generated from upstream catchment areas of a reservoir is normally estimated based on a design rainfall. However, rainfall generally varies in different seasons. This seasonal change may significantly influence the estimation of runoff volume and associated NPSP arising within a reservoir watershed. The NPSP management, reservoir operation, and water treatment operation strategies developed based on the estimation will also be altered. This study analyzes the effects of monthly and seasonal variation in precipitation on the estimation of pollution levels from nonpoint sources in a reservoir watershed. The area studied is the Derchi reservoir watershed located in central Taiwan. This watershed is subdivided into twenty-six sub-watersheds, and the Thiessen method is used to determine the rainfall intensity in each sub-watershed. Runoff pattern and NPSP contributions for each sub-watershed are estimated using the AGNPS model. Results show significant seasonal variation in precipitation; estimated NPSP loads likewise vary significantly over time. Seven- to one hundred-fold differences among monthly and seasonal estimations of phosphorus and sediment loads are observed.
Forecasting↗
Effect of rice--glycerol complex medium on the production of Lovastatin by Monascus ruber.
Response surface methodology (RSM) was employed to study the effect of the composition of the rice-glycerol complex medium on the production of lovastatin (Lvs) by the ascomycete Monascus ruber in mixed solid-liquid (or submerged) cultures at 25 degrees C. Four components (rice powder, peptone, glycerol, glucose) were studied to evaluate the approximate polynomial for all dependent variables, explaining their effects on the production of Lvs. The best composition derived from RSM regression was (in g/L) rice powder 34.4, peptone 10.8,, glucose 129, KNO3 8.0, MgSO4.7H2O 4.0 and glycerol 36.4 mL/L. With this composition, the Lvs production was 157 mg/L after 10 d of cultivation. In comparison with glycerol and glucose, the rice powder becomes a more suitable carbon source and represents a great potential for the production of Lvs.
Glucose↗
Characterization of high-sensitivity metal oxide semiconductor field effect transistor dosimeters system and LiF:Mg,Cu,P thermoluminescence dosimeters for use in diagnostic radiology.
Monitoring radiation exposure during diagnostic radiographic procedures has recently become an area of interest. In recent years, the LiF:Mg,Cu,P thermoluminescence dosimeter (TLD-100H) and the highly sensitive metal oxide semiconductor field effect transistor (MOSFET) dosimeter were introduced as good candidates for entrance skin dose measurements in diagnostic radiology. In the present study, the TLD-100H and the MOSFET dosimeters were evaluated for sensitivity, linearity, energy, angular dependence, and post-exposure response. Our results indicate that the TLD-100H dosimeter has excellent linearity within diagnostic energy ranges and its sensitivity variations were under 3% at tube potentials from 40Vp to 125kVp. Good linearity was also observed with the MOSFET dosimeter, but in low-dose regions the values are less reliable and were found to be a function of the tube potentials. Both dosimeters also presented predictable angular dependence in this study. Our findings suggest that the TLD-100H dosimeter is more appropriate for low-dose diagnostic procedures such as chest and skull projections. The MOSFET dosimeter system is valuable for entrance skin dose measurement with lumbar spine projections and certain fluoroscopic procedures.
Calibration↗
Single-neuron analysis of human thalamus in patients with intention tremor and other clinical signs of cerebellar disease.
Tremor that occurs as a result of a cerebellar lesion, cerebellar tremor, is characteristically an intention tremor. Thalamic activity may be related to cerebellar tremor because transmission of some cerebellar efferent signals occurs via the thalamus and cortex to the periphery. We have now studied thalamic neuronal activity in a cerebellar relay nucleus (ventral intermediate-Vim) and a pallidal relay nucleus (ventralis oral posterior-Vop) during thalamotomy in patients with intention tremor and other clinical signs of cerebellar disease (tremor patients). The activity of single neurons and the simultaneous electromyographic (EMG) activity of the contralateral upper extremity in tremor patients performing a pointing task were analyzed by spectral cross-correlation analysis. EMG spectra during intention tremor often showed peaks of activity in the tremor-frequency range (1.9-5.8 Hz). There were significant differences in thalamic neuronal activity between tremor patients and controls. Neurons in Vim and Vop had significantly lower firing rates in tremor patients than in patients undergoing thalamic surgery for pain (pain controls). Other studies have shown that inputs to Vim from the cerebellum are transmitted through excitatory connections. Therefore the present results suggest that tremor in these tremor patients is associated with deafferentation of the thalamus from cerebellar efferent pathways. The thalamic X EMG cross-correlation functions were studied for cells located in Vim and Vop. Neuronal and EMG activity were as likely to be significantly correlated for cells in Vim as for those in Vop. Cells in Vim were more likely to have a phase lag relative to EMG than were cells in Vop. In monkeys, cells in the cerebellar relay nucleus of the thalamus, corresponding to Vim, are reported to lead movement during active oscillations at the wrist. In view of these monkey studies, the present results suggest that cells in Vim are deafferented and have a phase lag relative to tremor that is not found in normal active oscillations. The difference in phase of thalamic spike X EMG activity between Vim and Vop may contribute to tremor because lesions of pallidum or Vop are reported to relieve cerebellar tremor.
Action Potentials↗
Protection against lethal enterovirus 71 infection in newborn mice by passive immunization with subunit VP1 vaccines and inactivated virus.
Enterovirus 71 (EV71), the newest member of Enteroviridae, is notable for its etiological role in epidemics of severe neurological diseases in children. Developing effective vaccines is considered a top choice among all control measures. We compared the inactivated virus vaccine (10 microg protein/mouse) with subunit vaccines--VP1 DNA vaccine (100 microg/mouse) or recombinant VP1 protein (10 microg/mouse)--in its ability to elicit maternal antibody and to provide protection against lethal infection of EV71 in suckling mice. Prior to gestation, all three groups of vaccinated dams possessed similar levels of neutralizing antibody. With a challenge dose of 2300 LD(50) virus/mouse, suckling mice born to dams immunized with inactivated virus showed 80% survival. The subunit vaccines provided protection only at a lower challenge dosage of 230 LD(50) per mouse, with 40% survival for DNA vaccine and 80% survival for VP1 protein. The cytokine profile produced by splenocytes showed a high level of IL-4 in the inactivated virus group, high levels of IFN-gamma and IL-12 in the DNA vaccine group, and high levels of IL-10 and IFN-gamma in the VP1 protein group. Overall, the inactivated virus elicited a much greater magnitude of immune response than the subunit vaccines, including total IgG, all four IgG subtypes, and T-helper-cell responses; these antibodies were shown to be protective against lethal infection when passively transferred to susceptible newborn mice. Our data indicated that inactivated virus is the choice of vaccine preparation capable of fulfilling the demand for effective control, and that VP1 subunit vaccines remain promising vaccine strategies that require further refinement.
Animals↗
Storage effects on bacterial concentration: determination of impinger and filter samples.
Effects of storage on the colony recovery of airborne bacterial samples were evaluated in a laboratory test chamber. Escherichia coli cells and Bacillus subtilis spores were generated by a Collison three-jet nebulizer. Bioaerosol samples were collected by three sampling methods, AGI-30 impingers, Nuclepore filtration and elution methods, and gelatin filters. Effects of storage time was determined by the ratio, Ct/C0, where Ct and C0 were the CFU concentrations of the simultaneously collected samples stored for t and 0 h, respectively. The effect of storage temperature was also studied for AGI-30 samples stored at 25 and 4 degrees C. For impinger samples, it was demonstrated that the bioefficiency of bacterial bioaerosols could survive in the impinger fluid, and even bud more cells at room temperature. In addition, the inhibition effect of refrigerated samples was observed. Therefore, we suggest that samples collected by an impingement method should be refrigerated and processed as soon as possible to avoid the increase of bacterial culturability. Moreover, the effect of storage time on filtration collection for B. subtilis spores was demonstrated to be insignificant. However, E. coli recovery from filters was demonstrated to decrease as storage time increased. It was concluded that the recovery would not decrease during storage if bioefficiencies of the sampling methods were excellent, for example, using filters to collect B. subtilis spores or impingers to collect E. coli cells.
Aerosols↗
Binding and partial denaturing of G-quartet DNA by Cdc13p of Saccharomyces cerevisiae.
The protein Cdc13p binds telomeres in vivo and is essential for the maintenance of the telomeres of Saccharomyces cerevisiae. In addition, Cdc13p is known to bind single-stranded TG(1-3) DNA in vitro. Here we have shown that Cdc13p also binds DNA quadruplex, G-quartet, formed by TG(1-3) DNA. Moreover, the binding of Cdc13p causes a partial denaturing of the G-quartet DNA. Formation of DNA quadruplexes may involve the intermolecular association of TG(1-3) DNA and inhibit the extension of telomeres by telomerase. Thus, our finding suggests that Cdc13p may disrupt telomere association and facilitate telomere replication.
Alkylating Agents↗
Solution structure of a Kunitz-type chymotrypsin inhibitor isolated from the elapid snake Bungarus fasciatus.
Bungarus fasciatus fraction IX (BF9), a chymotrypsin inhibitor, consists of 65 amino acid residues with three disulfide bridges. It was isolated from the snake venom of B. fasciatus by ion-exchange chromatography and belongs to the bovine pancreatic trypsin inhibitor (BPTI)-like superfamily. It showed a dissociation constant of 5.8 x 10(-8) m with alpha-chymotrypsin as measured by a BIAcore binding assay system. The isothermal titration calorimetry revealed a 1:1 binding stoichiometry between this inhibitor and chymotrypsin and apparently no binding with trypsin. We further used CD and NMR to determine the solution structure of this venom-derived chymotrypsin inhibitor. The three-dimensional NMR solution structures of BF9 were determined on the basis of 582 restraints by simulated annealing and energy minimization calculations. The final set of 10 NMR structures was well defined, with average root mean square deviations of 0.47 A for the backbone atoms in the secondary structure regions and 0.86 A for residues The side chains of Phe(23), Tyr(24), Tyr(25), Phe(35), and Phe(47) exhibited many long-range nuclear Overhauser effects and were the principal components of the hydrophobic core in BF9. To gain insight into the structure-function relationships among proteins in the BPTI-like superfamily, we compared the three-dimensional structure of BF9 with three BPTI-like proteins that possess distinct biological functions. These proteins possessed similar secondary structure elements, but the loop regions and beta-turn were different from one another. Based on residues at the functional site of each protein, we suggest that the flexibility, rigidity, and variations of the amino acid residues in both the loop and beta-turn regions are related to their biological functions.
Amino Acid Sequence↗
Analysis of large-volume DNA markers and polymerase chain reaction products by capillary electrophoresis in the presence of electroosmotic flow.
We have demonstrated on-line concentration and separation of DNA in the presence of electroosmotic flow (EOF) using poly(ethylene oxide) (PEO) solutions. After injecting large-volumes DNA samples, PEO solutions entered a capillary filled with 400 mM Tris-borate (TB) buffers by EOF and acted as sieving matrices. DNA fragments stacked between the sample zone and PEO solutions. Because sample matrixes affected PEO adsorption on the capillary wall, leading to changes in EOF, migration time, concentration, and resolving power varied with the injection length. When injecting phiX174 RF DNA-HaeIII digest prepared in 5 mM Tris-HCl buffer, pH 7.0, at 250 V/cm, peak height increased linearly as a function of injection volume up to 0.9 microl (injection time 150 s). The sensitivity improvement was 100-fold compare to that injected at 25 V/cm for 10 s (0.006 microl). When injecting 1.54 microl of GeneScan 1000 ROX, the sensitivity improvement was 265-fold. The sensitivity improvement was 40-fold when injecting 0.17 microl DNA sample containing pBR 322/HaeIII, pBR 328/BglI, and pBR 328/HinfI digests prepared in phosphate-buffered saline. This method allows the analysis of polymerase chain reaction (PCR) products amplified after 17 cycles when injecting 0.32 microl (at 30 cm height for 300 s). The total analysis time was shorter (91.6 min) than that (119.6 min) obtained from injecting PCR products after 32 cycles for 10 s.
Base Sequence↗
The anatomy of the nervous system of the hydrozoan jellyfish, Polyorchis penicillatus, as revealed by a monoclonal antibody.
Dissociated cells from the margin and tentacles of the hydromedusa Polyorchis penicillatus were centrifuged in a Percoll gradient to remove cnidocytes. The resulting formaldehyde-fixed cells were used to inoculate mice to produce monoclonal antibodies. One of the hybridomas, which secreted antibodies against all neurons, was cloned and designated as mAb 5C6. Immunohistochemical labelling with mAb 5C6 of whole-mount preparations and paraffin sections provided a far more complete picture of the organisation of the hydromedusan nervous system than was previously available when using neuronal labelling techniques that restrict labelling to certain neuronal types. Besides confirming anatomical features described in earlier studies these techniques allowed us to discover a number of new structures and to determine connections that were only suspected. Such findings included:1. The discovery of an arch-like connection between the swimming motor neuron network at the apices of the subumbrellar muscle sheets 2. An orthogonal network connecting each pair of radial nerves in each radius 3. Continuity of a central branch of the radial nerve with the radial innervation of the manubrium 4. Details of the sensory neuronal contribution to the microanatomy of the ocelli and cnidocyte batteries 5. Presence of specialised receptor cells in the margin at the bases of tentacles 6. Neurons apparently innervating the radial muscles of the velum 7. Isolated neurons in the peduncle and gonads
Animals↗
Renaturation and stabilization of the telomere-binding activity of Saccharomyces Cdc13(451-693)p by L-arginine.
Production of recombinant proteins can be valuable in studying their biological functions. However, recombinant proteins expressed in Escherichia coli sometimes form undesirable insoluble aggregates. Solubilization and renaturation of these aggregates becomes a problem that one needs to solve. Here we used recombinant Cdc13(451-693)p as example to show the presence of l-arginine during renaturation greatly enhanced the renaturation efficiency. Cdc13p is the single-stranded telomere-binding protein of yeast Saccharomyces cerevisiae. The telomere-binding domain has been mapped within amino acids 451-693 of Cdc13p, Cdc13(451-693)p. Recombinant Cdc13(451-693)p was expressed in E. coli as insoluble protein aggregates. Purification of insoluble Cdc13(451-693)p was achieved by denaturing the protein with 6 M guanidine-HCl and followed by Ni-nitrilotriacetic acid agarose column chromatography. Renaturation of Cdc13(451-693)p to the active form was achieved by dialyzing denatured protein in the presence of l-arginine. Moreover, the presence of l-arginine was also helped in maintaining the telomere-binding activity of Cdc13(451-693)p. Taking together, l-arginine might have a general application in renaturation of insoluble aggregates.
Arginine↗
An efficient synthesis of pyrrolo[2,1-c][1,4]benzodiazepine. Synthesis of the antibiotic DC-81.
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Antibiotics, Antineoplastic↗
Specific binding of single-stranded telomeric DNA by Cdc13p of Saccharomyces cerevisiae.
Cdc13p is a single strand telomere-binding protein of Saccharomyces cerevisiae; its telomere-binding region is within amino acids 451-693, Cdc13(451-693)p. In this study, we used purified Cdc13p and Cdc13(451-693)p to characterize their telomere binding activity. We found that the binding specificity of single-stranded TG(1-3) DNA by these two proteins is similar. However, the affinity of Cdc13(451-693)p to DNA was slightly lower than that of Cdc13p. The binding of telomeric DNA by these two proteins was disrupted at NaCl concentrations higher than 0.3 m, indicating that electrostatic interaction contributed significantly to the binding process. Because both proteins bound to strand TG(1-3) DNA positioned at the 3' end, the 5' end, or in the middle of the oligonucleotide substrates, our results indicated that the location of TG(1-3) in single-stranded DNA does not appear to be important for Cdc13p binding. Moreover, using DNase I footprint analysis, the structure of the telomeric DNA complexes of Cdc13p and Cdc13(451-693)p was analyzed. The DNase I footprints of these two proteins to three different telomeric DNA substrates were virtually identical, indicating that the telomere contact region of Cdc13p is within Cdc13(451-693)p. Together, the binding properties of Cdc13p and its binding domain support the theory that the specific binding of Cdc13p to telomeres is an important feature of telomeres that regulate telomerase access and/or differentiate natural telomeres from broken ends.
Animals↗
Design, synthesis, and biological evaluation of HIV/FIV protease inhibitors incorporating a conformationally constrained macrocycle with a small P3' residue.
A series of norstatine-based HIV/FIV protease inhibitors incorporating a 15-membered macrocycle as a mimic of the tripeptide (Ala-Val-Phe), a motif with a small P3' residue elective against the FIV protease and the drug-resistant HIV proteases, has been synthesized. It was found that the macrocycle is important to the overall activity of the inhibitors. Certain inhibitors were developed expressing low nanomolar inhibitory activity against the HIV/FIV proteases and they are also effective against some drug-resistant as well as TL3-resistant HIV proteases.
Amino Acid Motifs↗
Maximization of injection volumes for DNA analysis in capillary electrophoresis.
We report concentration and separation of DNA in the presence of electroosmotic flow (EOF) using poly(ethylene oxide) (PEO) solution. DNA fragments migrating against EOF stacked between the sample zone and PEO solution. To maximize the injection volume, several factors, such as concentrations of Tris-borate (TB) buffer and PEO solution, capillary size, and matrix, were carefully evaluated. The use of 25 mM TB buffers, pH 10.0, containing suitable amounts (less than 10 mM) of salts, such as sodium chloride, sodium phosphate, and sodium acetate, to prepare DNA is essential for the concentration of large-volume samples. In the presence of salts, the peaks also became sharper and the fluorescence intensity of DNA complexes increased. Using 2.5% PEO and a 150 microm capillary filled with 400 mM TB buffer, pH 10.0, up to 5 microL DNA samples (phiX 174 RF DNA-HaeIII digest or the mixture of pBR 322/HaeIII, pBR 328/Bg/I, and pBR 328/HinfI digests) have been analyzed, resulting in more than 400-fold improvements in the sensitivity compared to that by conventional injections (ca. 36 nL). Moreover, this method allows the analysis of 3.5 microL PCR products amplified after 17 cycles without any sample pretreatment.
Buffers↗
Separation of dsDNA in the presence of electroosmotic flow under discontinuous conditions.
Separations of phiX-174/HaeIII DNA restriction fragments have been performed in the presence of electroosmotic flow (EOF) using five different polymer solutions, including linear polyacrylamide (LPA), poly(ethylene oxide) (PEO), hydroxypropylcellulose (HPC), hydroxyethylcellulose (HEC), and agarose. During the separation, polymer solutions entered the capillary by EOF. When using LPA solutions, bulk EOF is small due to adsorption on the capillary wall. On the other hand, separation is faster and better for the large DNA fragments (> 872 base pairs, bp) using derivative celluloses and PEO solutions. Several approaches to optimum resolution and speed by controlling EOF and/or altering electrophoretic mobility of DNA have been developed, including (i) stepwise changes of ethidium bromide (0.5-5 microg/mL), (ii) voltage programming (125-375 V/cm), (iii) use of mixed polymer solutions, and (iv) use of high concentrations of Tris-borate (TB) buffers. The DNA fragments ranging from 434 to 653 bp that were not separated using 2% PEO (8,000,000) under isocratic conditions have been completely resolved by either stepwise changes of ethidium bromide or voltage programming. Compared to PEO solutions, mixed polymer solutions prepared from PEO and HEC provide higher resolving power. Using a capillary filled with 600 mM TB buffers, pH 10.0, high-speed (< 15 min) separation of DNA (pBR 322/HaeIII digest, pBR 328/ Bg/l digest and pBR 328/Hinfl digest) has been achieved in 1.5% PEO.
Bacteriophage phi X 174↗
Production of Acinetobacter radioresistens lipase with repeated batch culture in presence of nonwoven fabric.
Cultivation of Acinetobacter radioresistens on n-hexadecane for lipase production was investigated with repeated batch culture in the presence of a hydrophobic nonwoven fabric. Lipase production followed the growth-associated model, and the repeated batch culture could achieve both high enzyme yield and increased volumetric productivity. The fabric was shown to be able to disperse n-hexadecane, to adsorb the unused hydrocarbon, and to retain bioemulsifiers excreted from the cells; therefore, it enhanced cell growth and, in turn, lipase production. In the repeated batch culture in the absence of the fabric, lipase yield and volumetric productivity were found to be 21 U/mL and 875 U/L. h, respectively. However, if the fabric was equipped in the fermentor, lipase yield and volumetric productivity increased to 30 U/mL and 2500 U/L. h, respectively. The lipase production profile could be further improved by raising the amount of nitrogen source and, as a result, a lipase yield of 54 U/mL and a volumetric productivity of 2250 U/L. h were obtained. In this study we assess the beneficial effects of nonwoven fabric on lipase production.
Acinetobacter↗