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Biomedical subjects

S Y Lin

Publications and source records attributed to S Y Lin.

At least 199 records · Page 11Linked to original sources
PubMed1994

Evidence of possible carcinogenesis during conformational changes in bladder mucosa induced by bladder outlet obstruction.

Fourier transform infrared spectroscopy with attenuated total reflectance technique was applied to determine the mucosa on the surface of the rabbit urinary bladder wall before and after obstruction. Several abnormal spectra related to the hydrogen bonding in nucleic acids of protein, previously found in the colon malignant tissues, appeared in the infrared spectra of the obstructed bladder mucosa, which could not be found in normal bladder mucosa. Urinary bladder outlet obstruction seemed to induce carcinogenesis in the obstructed bladder mucosa by forming several infrared spectral abnormalities.

Animals↗
PubMed1994

Specific A+T-rich repetitive DNA sequences in maxicircles from wildtype Leishmania mexicana amazonensis and variants with DNA amplification.

To explain the low cross-hybridization between kinetoplast DNA maxicircles of Leishmania parasites that show DNA amplification and those of parasites without DNA amplification, we isolated and cloned two maxicircle fragments, one specific to each group of parasites. The cloned fragment from wildtype L. m. amazonensis (MbpW94) and that from an arsenite-resistant variant with DNA amplification (MpbA29) hybridized only to maxicircles from parasites of the group from which the fragment was originally derived. Both fragments were A+T-rich, tandemly repeated, and lacked long conserved open reading frames and transcriptional products. MpbW94 (685 bp) was harbored in a segment of roughly 12 kb in maxicircles of wildtype parasites and of an arsenite-resistant variant without DNA amplification, while MbpA29 (1121 bp) occupied a 6- to 7-kb segment of maxicircle DNA in arsenite- and tunicamycin-resistant variants with DNA amplification. These maxicircle DNA segments appear to resemble previously described maxicircle divergent regions of other kinetoplastids. The presence of these specific sequences allows differentiation between maxicircles of drug-resistant L. m. amazonensis with DNA amplification and those of parasites without DNA amplification and helps explain the low cross-hybridization between maxicircles of the two parasite groups. Furthermore, these sequences allow the study of the kinetics of the changeover of A+T-rich regions of maxicircles during the transition period from one maxicircle type to the other.

Animals↗
PubMed1994

The effect of vesical outlet obstruction on the protein secondary structure of the mucosa and serosa in rabbit bladder wall.

The biochemical composition of physiologically moist mucosa and serosa of rabbit bladder before and after bladder outlet obstruction was determined by means of FT-IR spectroscopy with the ATR method and second-derivative analysis. A predominantly beta-sheet structure was found in the amide I band for mucosa and serosa before and after obstruction, but the random coil structure increased in both obstructed bladder samples. However, the major beta-sheet structure associated with some alpha-helical structure in the amide II band of mucosa and serosa for non-obstructed bladder changed into a predominantly alpha-helical structure after bladder obstruction. The obstructed bladder serosa was more pronounced. The amount of glycoproteins doubled in the obstructed bladder serosa, but did not change in the bladder mucosa.

Animals↗
PubMed1994

Multiple genotypes of mitochondrial DNA within a horse population from a small region in Yunnan Province of China.

mtDNA genotypes of six domestic horses (three adult short horses whose heights are under 1 m and three common domestic horses) from a small region of 15 km2 in Malipo county of Yunnan province of China were investigated by the technique of restriction fragment length polymorphism (RFLP) with 16 restriction endonucleases which recognize 6-bp sequences. An average of 56 fragments for an individual was obtained. Unlike other domestic animals, this population of horses exhibits high mtDNA genetic diversity. Each of the six horses has a specific mtDNA genotype showing a pattern of multiple maternal origins, as suggested by fossil and literature records. We think the population of horses is an amazing seed-resource pool of horses and hence deserves to be paid more attention from the view of conservation genetics. However, it is also remarkable that we did not find any typical mtDNA genetic markers which would discriminate between short horses and common domestic horses.

Animals↗
PubMed1994

Sodium ion binding in the gramicidin A channel. Solid-state NMR studies of the tryptophan residues.

Gramicidin A analogs, labeled with 13C in the backbone carbonyl groups and the C-2 indole carbons of the tryptophan-11 and tryptophan-13 residues, were synthesized using t-Boc-protected amino acids. The purified analogs were incorporated into phosphatidylcholine bilayers at a 1:15 molar ratio and macroscopically aligned between glass coverslips. The orientations of the labeled groups within the channel were investigated using solid-state NMR and the effect of a monovalent ion (Na+) on the orientation of these groups determined. The presence of sodium ions did not perturb the 13C spectra of the tryptophan carbonyl groups. These results contrast with earlier results in which the Leu-10, Leu-12, and Leu-14 carbonyl groups were found to be significantly affected by the presence of sodium ions and imply that the tryptophan carbonyl groups are not directly involved in ion binding. The channel form of gramicidin A has been demonstrated to be the right-handed form of the beta 6.3 helix: consequently, the tryptophan carbonyls would be directed away from the entrance to the channel and take part in internal hydrogen bonding, so that the presence of cations in the channel would have less effect than on the outer leucine residues. Sodium ions also had no effect on the C-2 indole resonance of the tryptophan side chains. However, a small change was observed in Trp-11 when the ether lipid, ditetradecylphosphatidylcholine, was substituted for the ester lipid, dimyristoylphosphatidylcholine, indicating some sensitivity of the gramicidin side chains to the surrounding lipid.

Amino Acid Sequence↗
PubMed1994

A 300 kilobase interval genetic map of rice including 883 expressed sequences.

We have constructed a high resolution rice genetic map containing 1,383 DNA markers at an average interval of 300 kilobases (kb). The markers, distributed along 1,575 cM on 12 linkage groups, comprise 883 cDNAs, 265 genomic DNAs, 147 randomly amplified polymorphic DNAs (RAPD) and 88 other DNAs. cDNAs were derived from rice root and callus, analysed by single-run sequencing and searched for similarities with known proteins. Nearly 260 rice genes are newly identified and mapped, and genomic DNA and cloned RAPD fragments were also sequenced to generate STSs. Our map is the first significant gene expression map in plants. It is also the densest genetic map available in plants and the first to be backed up comprehensively by clone sequence data.

Chromosome Mapping↗
PubMed1994

Transformation of IR spectra of the human lens capsule due to traumatic lens subluxation and correlation with the excised and dried lens capsule under different treatments.

Transformation of the secondary conformational structure of the human lens capsule after traumatic lens subluxation in a patient was investigated by Fourier transform infrared (FT-IR) microscopic spectrometry. The result was compared with the IR spectra of type IV collagen in crystalline state, solid film and aqueous solution and those of the excised and dried lens capsule under compression or treated with ethyl alcohol. The results indicate that the IR spectra of the intact human lens capsule after traumatic lens subluxation were the same as those of the rabbit lens capsule, except in the 1,100-1,000 cm-1 proteoglycan region, but were different from those of type IV collagen aqueous solution at the amide I and II bands and the proteoglycan region, although type IV collagen is a predominant component of lens capsule. Two new peaks at 1,054 and 1,023 cm-1 appeared on the IR spectra of the intact human lens capsule and on those of type IV collagen in crystalline state and solid film after compression but not in normal rabbit lens capsule and native type IV collagen. It was also found that all the IR spectra of the excised and dried lens capsule were similar to those of native type IV collagen in crystalline state and solid film.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Determination of cadmium and lead in raw milk by graphite furnace atomic absorption spectrophotometer.

A simple, uncontaminated method was described for graphite furnace atomic absorption spectrophotometry used for determination of Cd and Pb in milk serum prepared by spontaneous souring. Samples of raw milk were collected from the bulk holding tanks of 107 dairy farms in six counties in Taiwan. Raw milk samples were placed at room temperature (28 degrees C) for 48 h, to allow the pH to decrease below 4.6 and the casein and fat to precipitate. Milk serum was filtered and then directly injected into a graphite tube. The standard addition method was employed, and .1% phosphoric acid was the matrix modifier. During ashing, a 15-s oxygen influx prevented charcoal accumulation on the graphite tube. The mean recoveries of Cd and Pb from three added concentrations were 93.7% and 94.5%, respectively. The analyzed Cd and Pb concentrations in milk powder using this method were close to the certified values. The mean Cd and Pb contents obtained from 107 samples were .044 ng/ml, ranging from .021 to .173, and 2.03 ng/ml, ranging from .98 to 4.45, respectively. There were no significant differences among the six counties.

Animals↗
PubMed1994

[Complications and management of percutaneous central venous access catheter].

The recently developed method of percutaneous subclavian implantation of an indwelling central venous catheter provides convenient access for patients requiring long-term intravenous therapy. To evaluate, clinical complications and its management, we reviewed 145 implanted central venous systems in 135 patients during a 7 month period. The implantation failed in two patients due to difficult subclavian punctures. The major complications were pinch-off sign observed in 5 patients, inflammation in 6 patients (4.2%), and subclavian vein thrombosis in 7 patients, and other miscellaneous complications in 7 patients. It was revealed the pressure between the clavicle and first rib attributed to "pinch-off sign", which could be avoided by a lateral subclavian vein approach. Meticulous disinfection before use of the system is advised since most infections was derived from the injection site. We also suggest the the catheter should be placed at the lower part of the superior vena cava because the development of thrombosis is highly poelated. Seven patients required removal of the system, however, all patients with complications had good Port A function adequate management or revision operation. Percutaneous subclavian implantation of indwelling central venous catheter is safe and reliable.

Adolescent↗
PubMed1994

Lower tibial osteotomy for osteoarthritis of the ankle.

Ankle arthrodesis is still the treatment of choice for most disabling arthritic ankles. But in spite of its popularity, ankle arthrodesis has many disadvantages, including long immobilization, a high pseudoarthrosis rate, and load shift with increased stress on neighboring joints of ankle. Lower tibial osteotomy is one of the methods which attempts to halt ankle arthritis in the intermediate stage and trying to prevent ankle arthroadesis. From Aug. 1989, we performed 8 operations of lower tibial osteotomy in our hospital on intermediate arthritic ankle which included 4 post-traumatic ankle arthritis and 4 ankle osteoarthritis. The patient's ages ranged from 21y/o to 72y/o with an average of 41.6y/o. The mean time of followed up was 31.7 months. The patients were evaluated by the ankle functional scale preoperatively and during their followed up. The average preoperative functional score was 49.6 and the last follow up score was 88.5 which is increasing year by year. Significant improvement occurred in function and pain relief and there was improvement of ankle motion in most patients except one. Complications included late infection in 1 patient and implant failure with subsequent revision surgery due to overcorrection in 1 patient. No nonunion was noted. Although our series was small, we had encouraging short-term results. We believe lower tibial osteotomy, by pressure redistribution on the joint surface, is an alternative for the treatment of ankle osteoarthritis and may save or delay arthritic ankle from the fate of fusion.

Adult↗
PubMed1994

Monoclonal antibodies specific for ohmefentanyl.

Ohmefentanyl (Ohm, N[1-(beta-hydroxy-beta-phenylethyl)-3-methyl-4- piperidyl]-N-phenylpro-pronamide), designed and synthesized by our laboratory, is a highly selective mu receptor agonist. After somatic cell fusion between splenocytes of BALB c mice, immunized by Ohm-BSA conjugate and NS-1 myeloma cells, 2 lines of hybridoma (D2 and F4) secreting monoclonal anti-Ohm antibodies (MAb) were obtained. Saturation and competition experiments showed that MAb-D2 and MAb-F4 bound to Ohm-BSA with high affinity and high specificity. Using radioligand binding assay and bioassay, we also found that MAb-D2 and MAb-F4 inhibited [3H] Ohm binding to rat brain opioid receptors in a dose-dependent manner and antagonized the effect of Ohm on the contraction of guinea pig ileum induced by electric field stimulation. These results suggested that MAb-D2 and MAb-F4 were 2 monoclonal antibodies specific for Ohm and could be useful as functional antagonists of Ohm.

Animals↗
PubMed1994

Hallux valgus: soft tissue procedure versus bony procedure.

Hallux valgus is one of the most common fore-foot problem in civilized populations. 49 feet of 33 cases, 8 males and 25 females with an average age of 50 years old, were treated surgically from 1987 to 1992 for hallux valgus and followed up for an average of 47.8 months, comprising 20 feet with McBride's soft tissue procedure and 29 feet of Mitchell metatarsal osteotomy. The clinical criteria for follow up included pain relief, cosmetic out look, shoe wearing comfort, metatarsophalangeal motion etc. 87.5% of the cases in the McBride's group and 95% of the cases in the Mitchell group were satisfied with the clinical results. The immediate post-operative metatarsophalangeal (MP) angle and intermetatarsal (IM) angle were both well corrected, but there was a significantly higher recurrence rate of hallux valgus in the group with the McBride's procedure (P < 0.05). One case in the McBride's group had the complication of hallux varus and one case from the Mitchell group had delayed union. The Mitchell bony procedure has a more stable result compared to the McBride's soft tissue procedure for the correction of moderate hallux valgus, and the modified Mitchell osteotomy is less invasive, easier to perform, easier to care for, and has more satisfactory long-term results.

Adolescent↗
PubMed1994

Perinatal characteristics of low birthweight infants in postdate pregnancies.

BACKGROUND: Early literature discussed postdate pregnancy in relation to difficult delivery of mothers with an excessively large fetus; more recent reports imply that the risk of perinatal death exists especially for the small, growth-retarded fetus. However there is little in the literature concerning low birthweight infants in postdate pregnancies. METHODS: A 6-year retrospective review of 135 low birthweight infants with 40 or more weeks' gestation was conducted. Among the subjects, 19 cases had a gestational age greater than 42 weeks (Group 1), 26 cases, between 41 and 42 weeks (Group 2), and 90 cases, between 40 and 41 weeks (Group 3). Assess was made of the outcomes of low birthweight infants in postdate pregnancies, comparing Group 1 with Group 2 and Group 3. RESULTS: Group 1 infants had significantly higher rates of chromosomal (21.1%) and congenital (31.6%) abnormalities and perinatal mortality (21.1%) than either Group 2 or Group 3 infants. Also, in Group 1 there were two cases of polyhydramnios and they both had abnormal karyotypes. CONCLUSIONS: The outcome of low birthweight infants in postdate pregnancies appears to be worse than predicted. This finding could offer for managing the cases which have a high frequency of abnormal karyotype (21.1%), especially when combined with polyhydramnios.

Adult↗
PubMed1994

["Pinch-off sign" and spontaneous fracture of an implanted central venous catheter: report of a case].

Percutaneous subclavian implantation of an indwelling central venous catheter is an easy technique and provides convenient venous access for long-term intravenous therapy. Although rarely reported, spontaneous fracture of the catheter is an ominous complication which requires a prompt diagnosis and urgent treatment. We present a case of "pinch-off sign" resulting in a spontaneous fracture of an indwelling central venous catheter. A 49-year-old female breast cancer patient was admitted and Port-A-Cath was implanted for chemotherapy. Immediately after the implantation, fluid infusion and blood withdrawal was smooth until clinical "pinch-off sign" developed 3 weeks later. Chest X ray revealed no abnormal findings. Extravasation of antineoplastic drugs was noted 113 days after operation. Fracture of the indwelling catheter was found at the clavicle-rib junction. The fractured fragment was removed with a transvenous snare under fluoroscope. There was no hemodynamic derangement during the peri-operative period. Microscopy studies suggested that intermittent pressure on the catheter between the clavicle and the first rib may be responsible. The catheter wore on the medial side ue to a tearing and scissoring effect associated with free shoulder joint movement exerted additional forces on this wearing point which led to catheter fracture. The relationship between the spontaneous catheter fracture and "pinch-off sign" is reviewed. Our suggestions are: (1) By avoiding the traditional cannulation of the median subclavian vein, the lateral subclavian vein, infraclavicular axillary vein or internal jugular vein should be better routes for implantation. (2) Chest X ray (anterior-posterior and lateral view) should be examined routinely 3 weeks after the operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Catheterization, Central Venous↗
PubMed1994

[Effect of ultrasonic extracting on the extraction rate of baicalin].

The method of extracting baicalin from Scutellaria baicalensis by ultrasound is studied. Compared with that of the decocting process which is usually used in medical industry, the method does not need to heat the medicine and can reduce the extraction time and raise the extraction rate.

Drugs, Chinese Herbal↗
PubMed1994

Precipitation profile of the intravenous induction agents.

To investigate the formation of precipitation between various intravenous agents, we cross-matched the anesthetic agents commonly used in the induction phase. Thiopentone and thiamylal precipitated in combination with non-depolarizing muscle relaxants, lidocaine, morphine, and meperidine. Ketamine and etomidate were naive to these agents. Crystalloidal solutions, such as lactated Ringer, normal saline, and dextrose solution did not contribute to the formation of precipitate. In conclusion, our study indicates that intravenous line must be irrigated before and after thiopentone and/or thiamylal. In order to prevent precipitate formation, mixtures of various drugs should be avoided until in vitro assay is done.

Anesthesia, Intravenous↗
PubMed1994

Recovery from propofol anesthesia: a quantitative electroencephalographic analysis.

Four numerical descriptors (median frequency, spectral edge frequency-95%, total power, and delta-ratio) derived from the computer-processed electroencephalogram (Neurometrics Lifescan) were analyzed for their ability to predict imminent arousal from total intravenous anesthesia with propofol. Fifteen patients undergoing minor surgical procedures without intubation were enrolled in the study. Arousal was defined as eye opening in response to verbal stimuli. During emergence from propofol, there were no significant changes among the descriptors except the delta-ratio. Significant change of delta-ratio occurred 210 seconds before patients' arousal and thereafter. An increase of delta-ratio value indicates that patients shifted from anesthetic to arousal state. It is concluded that the degree of delta-ratio change may be used for predicting patients' arousal from propofol anesthesia.

Adult↗