Biomedical subjects

S Y Lin

Publications and source records attributed to S Y Lin.

At least 19 recordsLinked to original sources

PubMed1992

Isolation and solid-state characteristics of a new crystal form of indomethacin.

A new polymorphic crystal form of indomethacin was precipitated from an aqueous solution of indomethacin and beta-cyclodextrin by titration with a 0.5 N HCl aqueous solution. Three polymorphs (alpha, beta, and gamma forms) and a new crystal form were differentiated with thermal analysis, infrared spectroscopy, powder X-ray diffractometry, thin-layer chromatography, elemental analysis, and Fourier transform infrared (FTIR) spectroscopy with a newly developed FTIR microscope equipped with a thermal analyzer. The new crystal polymorph of indomethacin exhibited endo- and exothermic peaks near 102.8 and 104.1 degrees C, respectively, because of phase transitions without weight loss, followed by two additional endothermic peaks at 151 and 158.9 degrees C, because of fusion. The differential scanning calorimetry-FTIR system can be used to examine the correlation between structural change of C = O stretching bands of this new polymorph and its thermal response. The new crystal form contained some gamma-form crystals, determined with an FTIR microscope equipped with a mapping option. Solid-state carbon-13 nuclear magnetic resonance spectra of the polymorphs of indomethacin were also examined.

Calorimetry, Differential Scanning↗

PubMed1992

Protective effects of an oral microencapsulated Mycoplasma hyopneumoniae vaccine against experimental infection in pigs.

Oral microencapsulated Mycoplasma hyopneumoniae vaccines were tested for their ability to prevent mycoplasmal pneumonia in pigs. Eighteen four-week-old specific pathogen free pigs were divided into six groups of three. Each pig of groups 1 to 4 was inoculated intramuscularly with formalin-inactivated M hyopneumoniae in adjuvant and boosted orally 14 days later with four different microencapsulated vaccine microspheres. Group 5 was used as a positive control. All 15 pigs of groups 1 to 5 were challenged at 28 days after the first vaccination by an intratracheal inoculation of pneumonic lung suspension. The three pigs of group 6 were used as a negative control. All four vaccinated groups showed some protection when challenged, but the protection was more solid in pigs boosted with vaccine D (group 4) which contained less porcine serum in the microsphere. The study indicates that oral vaccination with M hyopneumoniae could play a role in prevention and eradication of mycoplasmal pneumonia in the pig.

Administration, Oral↗

PubMed1992

Effect of traditional Chinese herbal medicines on the pharmacokinetics of western drugs in Sprague-Dawley rats of different ages (II): Aminophylline-huan shao tan and aminophylline-pu chung yi chi tang.

The effect of Chinese herbal medicines (Huan Shao Tan and Pu Chung Yi Chi Tang) and western drugs (sodium phenobarbital and cimetidine) on the serum concentration and pharmacokinetic parameters of theophylline and cytochrome P-450 of Sprague-Dawley (SD) rats of three different ages were examined. The older rats without pretreatment with Chinese herbal medicines and western drugs exhibited higher serum theophylline concentration and lower pharmacokinetic parameters of theophylline than middle-aged and younger rats (P < 0.05), but there was no difference in cytochrome P-450 activity among the three different ages of rats. All rats when pretreated with sodium phenobarbital showed lower serum theophylline concentration and higher pharmacokinetics parameters of theophylline. Also, the activity of cytochrome P-450 was higher (P < 0.05). When cimetidine was pre-administered in SD rats of three age groups, all rats exhibited lower serum theophylline concentration and higher pharmacokinetics parameters (P < 0.05), but the activity of cytochrome P-450 remained unchanged (P > 0.05). The results were opposite to other studies, probably because the dose and dosing intervals were different. No single effect occurred on the younger and middle-aged rats after pretreatment with Huan Shao Tan and Pu Chung Yi Chi Tang: their serum theophylline concentration, pharmacokinetics parameters and cytochrome P-450 activity were the same as the control group. However, the older rats after pretreatment with Huan Shao Tan or Pu Chung Yi Chi Tang showed lower serum theophylline concentration and higher pharmacokinetics parameters than the younger and middle-aged rats pretreated with similar Chinese herbal medicines. This indicates that Huan Shao Tan and Pu Chung Yi Chi Tang may perhaps improve the elimination of theophylline in older rats. This might be attributed to the increase in hepatic blood flow or in liver volume, since the activity of cytochrome P-450 was not affected by the administration of Chinese herbal medicines.

Aging↗

PubMed1992

Calcium alginate beads as core carriers of 5-aminosalicylic acid.

The utilization of calcium alginate beads as core carriers for delayed dissolution followed by burst release as a potential method of intestinal site specific drug delivery was investigated. 5-Aminosalicylic acid was spray-coated on dried calcium alginate beads and then coated with different percentages of enteric coating polymer and/or sustained-release polymer. Beads coated with more than 6% (w/w) methacrylic copolymer plastisized with dibutyl sebacate and triethyl citrate resisted release in 2-hr acid fluid challenge and allowed immediate dissolution upon transfer to simulated intestinal fluid. With 6% (w/w) methacrylic copolymer on top of 4% (w/w) ethylcellulose polymer, the major portion of drug did not release in 2 hr of acid treatment or the next 3 hr of simulated intestinal fluid treatment. This dosage form provides the possibility to deliver drug to the lower intestinal tract with minimal early release, followed by sustained release in the colon.

Alginates↗

PubMed1992

The effect of high-intensity trunk exercise on bone mineral density of postmenopausal women.

The purpose of this study was to determine the effect of a 1-year trunk resistive exercise program on bone mineral density at the lumbar spine and hip in postmenopausal women. Forty-nine subjects were divided into exercise and control groups. Dual photon absorptiometry was used to measure bone mineral density and the Muscle Examination and Exercise Dosimeter 3000 system was used to assess trunk muscle strength. Resistive exercise target levels for the exercise group were based on the results of the trunk muscle strength tests. The exercise group performed 3 sets of 10 repetitions for each of the sit-up, prone trunk extension, and double leg flexion exercises. The subjects were seen once per month and performed the exercises a minimum of three times per week. The bone mineral density and strength tests were done at baseline, at 6 months and at 12 months. The results of the study showed that 1) the dual photon absorptiometry method and the Muscle Examination and Exercise Dosimeter 3000 system were highly reliable in measuring bone mineral density and trunk muscle strength, respectively; and 2) no significant differences were found between the exercise and control groups at lumbar vertebrae L2, L3, L4, L2-L4, and the femoral neck, Ward's triangle, and trochanteric region of the proximal femur at baseline, 6-month, and 12-month evaluation sessions.

Absorptiometry, Photon↗

PubMed1992

Adsorption and desorption of indomethacin on cellulose-like biopolymers: chitin and chitosan.

The adsorption-desorption effect of cellulose-like biopolymers such as chitin and chitosan, and microcrystalline cellulose on indomethacin was investigated. The adsorptive capacity was ranked in the order: chitosan greater than chitin greater than microcrystalline cellulose. All the adsorption isotherms were found to follow Langmuir and Freundlich equations. However, chitosan-acetate gel powders and chitosan powders with pre-added acetic acid and methanol did not follow these equations, due to gel formations that led to more adsorption of indomethacin on the interlayer space of the gel. The strong adsorption of chitosan might result in difficult desorption of indomethacin.

Carbohydrate Sequence↗

PubMed1992

High prevalence of hepatitis C virus infection in aborigines in Taiwan.

In Taiwan, the epidemiological status of HCV infection is similar to those observed in other areas of the world, with 1.0% prevalence among adult volunteer blood donors and high prevalences among the high risk groups, by the detection of anti-HCV with synthetic peptide antigens. However, unusually high prevalences, 35.1%, 15.8% and 14.2%, were observed among adult populations in three of the five aboriginal communities. No difference in sex specificity was noted. In 37 (75.0%) of the 48 anti-HCV-positive cases, HCV-RNA was detected by reverse transcription polymerase chain reaction (RT-PCR) assay. None of such particular risk factors as tattooing, sexual promiscuity, operation, blood transfusion, nor intravenous drug abuse could be accounted for this high prevalence of HCV infection. No helpful supporting evidence for ethnic specificity was noted, either. Although a possible sexual transmission between spouses was observed, it is unlikely to be the main cause of the high prevalence in these aboriginal communities. We conclude that the unusually high prevalence of HCV infection observed in some aboriginal communities in Taiwan could be ascribed to poor anti-septic medical practice derived from insufficiency of medical personnel and facilities in these communities as compared with the other regions in Taiwan at the time before twenty years ago.

Adolescent↗

PubMed1992

Detection and differentiation of dengue-1 from Japanese encephalitis virus infections by ABC MAC-ELISA.

An IgM antibody capture enzyme linked immunosorbent assay using avidin biotin complex system (ABC MAC-ELISA) was established for the detection and differentiation of dengue-1 and Japanese encephalitis virus infections. The cut-off value of MAC-ELISA was based on the mean value of optical density at 490 nm of seven negative human sera carried along in each assay multiplied by 2.1. The specificity of MAC-ELISA tested on 200 healthy enrolled male serum was 99.5% and 98.0% for dengue-1 and Japanese encephalitis IgM, respectively. Two hundred and sixty-six acute or followed-up dengue serum specimens which were identified to possess dengue-1 virus by virus isolation technique using C6/36 cell line and monoclonal antibody immunofluorescent assay (IFA) were tested by MAC-ELISA for IgM antibodies to dengue-1 and Japanese encephalitis virus infection. The positivity of IgM antibody for serum collected from day 1 to day 7 after onset of the disease was 0.0%, 0.0%, 7.6% 14.2%, 25.0%, and 77.7% by each consecutive day, correspondingly, for those collected from day 8 to two month was 96.7% overall. By comparison the P/N value of dengue-1 IgM to JE IgM, 98.5% and 96.8% of the dengue-1 and Japanese encephalitis suspected serum specimens could be distinguished from each other, respectively. MAC-ELISA is a convenient, rapid, sensitive and specific method for the detection and differentiation of dengue-1 from Japanese encephalitis virus infections.

Antibodies, Viral↗

PubMed1992

Reconstruction of the severely deficient acetabulum with the bipolar prosthesis and allo-autograft.

We reviewed the clinical results and radiographs of four patients who had revision of the acetabular component of a failed total hip arthroplasty with a bipolar socket supplemented by autoallograft to reconstruct massive bony defect. These patients were followed up from twelve to seventeen months. The clinical score was assessed by a modified d'Aubigne's rating score that assigned a maximum of 18 points. The preoperative clinical score ranged from 1 to 5 points (mean: 3.25 points). The postoperative score improved to a range of 13-17 points (mean: 15.25 points). Of the hips examined, nearly all were pain-free. The largest possible bipolar cup was used with solid structural allografting augmented by morseled cancellous autograft. These have been uniformly trouble-free with acetabular reconstitution. Cup migration was minimal or none. The follow-up periods were short and some migration is probably to be anticipated in the future. Although this technique was originally conceived as part of a staged procedure, it seemed as a definitive procedure yielding acceptable results for dealing with a severely deficient acetabulum. Larger series and longer periods of follow-up are demanded to support this assertion.

Acetabulum↗

PubMed1992

Instrumented laxity test for the evaluation of posterior cruciate ligament reconstructed knee.

By making anterior and posterior drawer tests using "Laxity tester" is an objective way to evaluate the resting position of tibia plateau and knee laxity. This study followed up 16 cases of PCL reconstructed or pull-out repaired knees for an average of two years and seven months. A force of 20 1b was applied to evaluate knee laxity at 30 degree and 90 degree knee flexion. From paired t-test, the stability of reconstructed knees was not statistically different from that of control contralateral normal knees. The functional scores measured by the Gillquist scoring system for injured knees after reconstruction were satisfactory. Therefore the restabilized PCL deficient knees by the modified Clancy method or pull-out repair yielded good evaluation scores. The data of contralateral normal knee laxity obtained in this study was used as reference in pre-operative and post-operative evaluation of PCL injured knee.

Female↗

PubMed1992

In vitro release, pharmacokinetic and tissue distribution studies of doxorubicin hydrochloride (Adriamycin HCl) encapsulated in lipiodolized w/o emulsions and w/o/w multiple emulsions.

The lipiodolized w/o emulsion or w/o/w multiple emulsion containing Doxorubicin hydrochloride (1; Adriamycin HCl) with different emulsifiers was prepared to evaluate in vitro sustained-release behavior, pharmacokinetic and tissue distribution function in Sprague Dawley (SD) rats. The results of dissolution indicate that the release of 1 was significantly sustained for both emulsions when HCO-60 (polyoxyethylene (60) hydrogenated castor oil) was used as an emulsifier. The serum concentration of 1 was reduced and prolonged for both emulsions with the increase of HCO-60. The C(max) level was lowered and T(max) value was delayed after administration of w/o emulsions with higher HCO-60 concentration. The apparent terminal half-life for 1 released from some emulsions with higher concentration of HCO-60 was 3-folds higher than that of the 1 solution. The clearance of some w/o or w/o/w ADR emulsions also decreased with the increase of HCO-60. Not only the concentration of 1 in heart and kidney decreased significantly after the administration of w/o emulsions with the higher concentration of HCO-60, but also the hepatic concentration of 1 was higher and increased with HCO-60 concentration. The hepatic 1 level became lower after administration of w/o/w multiple emulsions with the increase of HCO-60; however, the concentration of 1 in heart, lung and spleen increased somewhat. The results indicate that lipiodol and HCO-60 seemed to play an important role in the prolongation and selective retention of w/o emulsion or w/o/w multiple emulsion, in vitro and in vivo.

Animals↗

PubMed1992

Oblique sliding metatarsal osteotomy for pressure metatarsalgia.

The transverse arch of the foot is formed by metatarsals which heads lie in a straight line to endure most of the loading of the forefoot. Malalignment of one or more metatarsal heads will result in increased loading and produce local tender plantar callosity. The treatment of pressure metatarsalgia must aim for it's pathomechanic cause, that is, hyper-extension of metatarsophalangeal joint. We have modified the distal metatarsal osteotomy to treat 40 toes in 22 cases. Follow up for an average of 21.3 months (ranging from 18 months to 31 months) indicated 19 cases (86.4%) with satisfactory results. The 3 cases with unsatisfied results were all due to early removal of the pin. Maximum oblige sloping of the osteotomy makes the osteotomy slide more easily and ensures union. Intramedullary pinning and early weight bearing maintain the osteotomic alignment, prevent foot stiffness and allow the distal fragment telescopes to be adequately positioned to prevent over correction which leads to transfer lesion. Compared to other methods, modified metatarsal osteotomy is less invasive, preserves natural structure, is easily performed and easy cared for which leads to effective and stable results.

Adult↗

PubMed1992

Comparisons of different animal skins with human skin in drug percutaneous penetration studies.

The in vitro penetration of theophylline, sodium diclofenac and benzoic acid through artificial cellulose membrane and eight animal skins was investigated. The intact animal skins including stratum corneum (SC) and viable epidermis were taken from frog, snake with or without scales, nude mice, Sprague-Dawley rat, porcine and human prepuce and thigh skin. The results indicated that the penetration was fastest through cellulose membrane and frog skin and slowest through human prepuce and thigh skin. The snake skin with scales slowed down the penetration rate more significantly than the scaled skin. Benzoic acid was the fastest penetrant through all animal skins. The permeable behaviors of sodium diclofenac through SC and intact skin of snake, porcine and human were compared. In porcine, sodium diclofenac penetrated through SC at a rate 33 times higher than through intact skin, but in snake and human skin, the rate through SC was only 2.2 and 1.6 times higher than through intact ones. This implies that both viable epidermis and SC were the major rate limiting barriers in drug penetration. DSC thermograms and IR spectra showed that the SC of snake, porcine and human thigh were very similar in structure and components. The study suggests that snake skin, porcine skin and human prepuce skin could replace the human skin in in vitro drug penetration experiments.

Animals↗

PubMed1991

Extragonadal and poor risk nonseminomatous germ cell tumors. Survival and prognostic features.

One hundred forty-nine patients with poor risk nonseminomatous germ cell tumors (NSGCT) treated between 1975 and 1988 were studied. Patients were considered poor risk if they had an extragonadal primary site or testicular NSGCT with low predicted probability of achieving a complete response (CR). Primary sites were the testis (99 patients), retroperitoneum (18 patients), and mediastinum (32 patients). Patients with mediastinal NSGCT had lower human chorionic gonadotropin (HCG) (P less than 0.0001) and lactate dehydrogenase (LDH) levels (P less than 0.0001), and more frequent yolk sac elements (P = 0.002). CR rates were 38% for mediastinal, 61% for retroperitoneal, and 38% for testicular primary sites. Mediastinal NSGCT patients more frequently required resection of residual malignancy to attain a CR (6 of 12). Mediastinal NSGCT had the worst event-free survival (P = 0.02). Cox regression analysis identified brain or liver metastases as the most important predictor of event-free survival in poor risk patients. Retroperitoneal NSGCT often have a poor outcome due to advanced presentation, but the likelihood of a CR to therapy can be predicted using criteria applicable to testicular primary tumors. Therefore, not all retroperitoneal NSGCT are poor risk, and retroperitoneal tumors are probably of occult testicular origin. Mediastinal NSGCT have distinct clinical and pathologic features, do not respond as well to chemotherapy, relapse more frequently, and have the worst survival. The likelihood of a CR cannot be predicted using criteria developed for primary testicular tumors, suggesting that mediastinal primary NSGCT is a distinct clinical entity.

Abdominal Neoplasms↗

PubMed1991

The effect of plasticizers on compatibility, mechanical properties, and adhesion strength of drug-free Eudragit E films.

The use of plasticizers to affect the properties of drug-free, self-adhesive Eudragit E-100 films with higher transparency was tested for possible transdermal drug delivery. Triacetin was found to be an effective first plasticizer for Eudragit E-100 polymer. In order to improve the flexibility and adhesiveness of Eudragit E-100 film plasticized with triacetin, a more flexible and adhesive, secondary plasticizer was added. Plasticizer-polymer compatibility was evaluated by measuring transparency, surface topography, and solubility. Secondary plasticizers with a low molecular weight and a solubility parameter similar to that of Eudragit E-100 polymer and triacetin were compatible. Further, a lower molecular weight or higher concentration of the secondary plasticizers might lead to greater plasticizing action, reduce tensile strength, and increase film elongation, independent of the hydrophilicity of the plasticizer. The adhesive strength of Eudragit E-100 film under a 180 degrees peel test was also affected by the molecular weight and solubility parameter of the secondary plasticizers used. The results indicate that PEG 200, propylene glycol, diethyl phthalate, and oleic acid can serve as a secondary plasticizer to improve the transparency, flexibility, and adhesion of Eudragit E-100 film.

Acrylic Resins↗

PubMed1991

Tablet formulation study of spray-dried sodium diclofenac enteric-coated microcapsules.

Sodium diclofenac enteric-coated microcapsules were prepared by a spray-drying technique with Eudragit L 30D as enteric-coating material. The spray-dried powder, mixed with neocel or flo-starch, or the mixture of neocel and flo-starch (weight ratio, 1:1) was directly compressed into a tablet. The micromeritic properties of the spray-dried powder and the mixed powder for tableting were investigated. The flowability of the spray-dried powder was poor but improved after incorporating the excipients. The release rates of sodium diclofenac from the spray-dried powder, the mixed powder before tableting, and the tablets were determined in 0.1 N HCl solution, pH 6.8, phosphate buffer solution, distilled water, and pH-changed medium. The results indicated that the spray-dried powder, the mixed powder before tableting, and the tablets all exhibited enteric-coated release properties; these powders and tablets showed some resistance to stimulated gastric acid and then released drug more rapidly in pH 6.8 buffer solution. The weight ratio of neocel to flo-starch plays an important role in controlling the release of sodium diclofenac from enteric tablets. The 1:1 weight ratio of neocel to flo-starch was more suitable for designing the microdispersed sodium diclofenac enteric-coated tablets.

Acrylates↗

PubMed1991

Renal nerves and the natriuresis following unilateral renal exclusion in the rat.

Both acute unilateral nephrectomy (AUN) and acute ureteral pressure elevation (UPE) stimulate sodium excretion (UNaV) from the contralateral kidney, a response which in each case is interrupted by prior denervation of either kidney. Yet the natriuresis after AUN is known to be related to an increase in the plasma concentration of a gamma-melanocyte stimulating hormone (gamma-MSH)-like peptide. In anesthetized rats, sham AUN had no effect on contralateral UNaV, and plasma immunoreactive (IR) gamma-MSH concentration was 10.6 +/- 3.0 (SD) fmol/ml. In rats with intact renal innervation, UNaV more than doubled after AUN (P less than 0.001), and IR-gamma-MSH was increased to 14.9 +/- 4.6 fmol/ml (P less than 0.025). Unilateral renal denervation led to the expected increase in ipsilateral and decrease in contralateral UNaV, and neither sham AUN nor AUN of the denervated of innervated kidney influenced UNaV. In all three of these groups, IR-gamma-MSH concentration was reduced below the sham or post-AUN values seen in rats with innervated kidneys, to 4.9 +/- 3.3, 3.8 +/- 3.4, and 2.8 +/- 3.5 fmol/ml, respectively (P less than 0.001 for all). These results suggested that removal of renal afferent nerve input by renal denervation lowered basal IR-gamma-MSH activity and prevented the stimulated level normally seen after AUN. To examine the effect of stimulating afferent renal nerve activity, we carried out UPE, a maneuver known to increase ipsilateral afferent renal nerve traffic through activation of renal mechanoreceptors, as well as cause a natriuresis from the contralateral kidney.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Effect of traditional Chinese herbal medicines on the pharmacokinetics of western drugs in SD rats of different ages. I. Aminophylline-Tin chuan Tang and aminophylline-Hsiao Ching Long Tang.

The effect of the traditional Chinese herbal medicines (Tin Chuan Tang and Hsiao Ching Long Tang) on the serum concentrations and pharmacokinetics of aminophylline was examined in three different ages of SD rats. Each traditional Chinese herbal medicine was orally preadministered to SD rats for one week and then aminophylline was administered intravenously. The serum concentrations and pharmacokinetic parameters of theophylline were estimated by a two-compartment open model. The liver isolated after the last blood sampling was homogenized and the activity of hepatic cytochrome p-450 was determined. Significant difference was found in some pharmacokinetic parameters of theophylline such as K10, t 1/2, Cl and Vd for three different ages of SD rats without pretreatment with Chinese herbal drugs (p less than 0.05). However, pretreatment with Tin Chuan Tang or Hsiao Ching Long Tang did not affect the pharmacokinetic parameters of theophylline in three different ages of SD rats (p greater than 0.05). We also found that there was no correlation between age and activity of cytochrome p-450 of SD rats (p greater than 0.05). The decline in some pharmacokinetic parameters of theophylline in the elderly rats perhaps might be attributed to the decrease in hepatic blood flow and liver volume. It is concluded that there was no drug interaction between theophylline and Tin Chuan Tang or Hsiao Ching Long Tang in the different ages of SD rats.

Age Factors↗