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Biomedical subjects

J M Lin

Publications and source records attributed to J M Lin.

At least 73 records · Page 4Linked to original sources
PubMed1995

Studies on Taiwan folk medicine, thang-kau-tin (II): Measurement of active oxygen scavenging activity using an ESR technique.

Using an electron spin resonance (ESR) technique, we measured the superoxide radical (O2) and hydroxyl radical (OH) scavenging activity from Mallotus repandus (Willd.) Muell.-Arg., Bauhinia championii Benth., Uncaria hirsuta Haviland and Uncaria rhynchophylla Miquel. O2- and OH were detected as spin adducts of spin traps 5,5-dimethylpyrroline-N-oxide (DMPO). The scavenging potencies of water extracts of crude drugs were evaluated in terms of their ability to reduce the peaks of spin adducts. The extract of B. championii showed the greatest superoxide radical and hydroxyl radical scavenger activity.

Ascorbic Acid↗
PubMed1995

Cerebral embolism from the thrombus in the atrioventricular septal aneurysm.

Atriventricular septal aneurysm is a rare finding. Thrombus within the atrioventricular septal aneurysm has never been reported. Here, we report a girl with sudden-onset hemiparesis. Magnetic resonance imaging of the patient's head revealed a lesion at the right basal ganglion. Cerebral infarction was impressed. A series of examinations was performed to find the source of the cerebral embolism. Transthoracic echocardiography further showed a thrombus in the aneurysm. A subsequent operation revealed a fresh thrombus in the aneurysm. The presence of an anatomic substrate such as this might justify anticoagulation treatment or even surgical intervention before thromboembolism occurs.

Adult↗
PubMed1995

Mitral valve aneurysm and infective endocarditis: report of four cases.

From March 1992 to March 1994, four cases of mitral valve aneurysm were diagnosed at National Taiwan University Hospital. Mitral valve infective endocarditis was documented in three patients, while aortic valve infective endocarditis was found in the other. The diagnosis of mitral valve aneurysm was based on characteristic echocardiographic findings. The mitral valve aneurysms in these four cases were all visualized by transesophageal but not transthoracic echocardiography. At the time of diagnosis, three patients with a history of mitral valve endocarditis had perforated mitral valve aneurysms and severe mitral regurgitation. Although not found before surgery, the remaining patient with a history of aortic valve endocarditis was noted to have an unperforated mitral valve aneurysm one month after aortic valve replacement. All three patients with severe mitral regurgitation underwent mitral valve replacement and the patient with an unperforated mitral valve aneurysm was managed conservatively and obtained a stable clinical condition. In conclusion, mitral valve aneurysm usually appears to be associated with infective endocarditis and transesophageal echocardiography is more helpful in the diagnosis of mitral valve aneurysm than transthoracic echocardiography. Furthermore, unperforated mitral valve aneurysms may be managed conservatively with careful follow-up.

Adult↗
PubMed1994

Left atrial appendage function determined by transesophageal echocardiography in patients with rheumatic mitral valve disease.

Left atrial thrombi have been considered to be the major source of systemic arterial embolization in patients with rheumatic mitral valve disease. Almost half of the left atrial thrombi are found in the left atrial appendage (LAA). To investigate LAA size and LAA contractile function in patients with rheumatic mitral valve disease, transesophageal echocardiographic and Doppler studies were performed in 61 patients. Among them, 46 patients were in atrial fibrillation (group 1), while the other 15 were in sinus rhythm (group 2). Thirty-six patients with nonrheumatic atrial fibrillation were chosen as control to group 1. Another 22 patients with various cardiovascular diseases and sinus rhythm served as control to group 2. When compared to the patients with nonrheumatic atrial fibrillation (control group), group 1 patients tended to have a larger LAA maximal area (9.7 +/- 5.2 vs. 5.9 +/- 2.8 cm2; p < 0.001). LAA ejection fraction and LAA peak emptying velocity were also lower. A significantly higher incidence of LAA spontaneous echo contrast (SEC) and thrombus formation was also found in these patients. Group 2 patients were also found to have a larger LAA maximal area when compared to the control group (8.8 +/- 3.7 vs. 5.2 +/- 3.0 cm2; p < 0.001). LAA ejection fraction and LAA peak emptying velocity were lower in this group, too. A higher incidence of LAA SEC formation was found in these patients with rheumatic mitral valve disease (4/15 vs. 0/22; p = 0.021). There was no significant difference, however, in LAA thrombus formation between group 2 and its control group (1/15 vs. 1/22; p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Usefulness of pulmonary venous flow pattern and maximal mosaic jet area detected by transesophageal echocardiography in assessing the severity of mitral regurgitation.

Pulmonary venous flow pattern detected by transesophageal echocardiography (TEE) has been reported to be a good marker of mitral regurgitation (MR) severity. In 89 patients with MR detected by TEE, both pulmonary venous flow pattern and maximal mosaic jet area were recorded for evaluating the severity of MR. Cardiac catheterization was performed in all patients for grading the severity of MR. Systolic reversed flow in pulmonary veins was a good marker for angiographic grade 3 or 4 MR with a sensitivity of 97% (33 of 34) and specificity of 95% (52 of 55). Maximal mosaic jet area had a good correlation with the grading of MR (r = 0.79). When a maximal mosaic jet area of > 6 cm2 was used to detect grade 3 or 4 MR, the sensitivity and specificity were lower than those of the systolic reversed flow (sensitivity 82 vs 97%, p = 0.073; specificity 80 vs 95%, p = 0.013). The accuracy of systolic reversed flow was not influenced by the cardiac rhythm or jet eccentricity. However, the sensitivity of maximal mosaic jet area was lower in patients with an eccentric jet than in patients with a central jet (67 vs 95%, p = 0.046). In conclusion, systolic reversed flow in pulmonary veins detected by TEE is better than the maximal mosaic jet area in detecting grade 3 or 4 MR, especially in patients with eccentric jet.

Adolescent↗
PubMed1993

Effects of isothiocyanates on tumorigenesis by benzo[a]pyrene in murine tumor models.

Previous studies have shown that benzyl isothiocyanate (BITC) inhibited lung tumorigenesis induced in A/J mice by benzo[a]pyrene (BaP), but other experiments using a somewhat different protocol demonstrated that phenethyl isothiocyanate (PEITC) had no effect on lung tumorigenesis induced by BaP in this strain. In contrast, PEITC but not BITC had been shown to inhibit lung tumorigenesis induced by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in A/J mice. Therefore, one goal of this study was to directly compare the chemopreventive activities of BITC and PEITC on BaP-induced lung tumorigenesis in A/J mice. In the same experiment we also compared the tumorigenic activities of BaP and NNK. Either BITC or PEITC was administered by gavage 15 min before gavage of BaP. This regimen was carried out three times at 2-week intervals, and the mice were sacrificed 26 weeks after the first treatment. As assessed by tumor multiplicity, BITC but not PEITC significantly inhibited lung tumorigenesis by BaP, whereas PEITC but not BITC significantly inhibited forestomach tumorigenesis. Comparison of the tumorigenic activities of NNK and BaP demonstrated that NNK was about ten times more potent than BaP as a lung tumorigen, while BaP but not NNK induced forestomach tumors. In a second set of experiments we evaluated the effects of isothiocyanates on the mouse skin tumor-initiating activity of BaP. The isothiocyanates tested were BITC, PEITC, 6-phenylhexyl isothiocyanate (PHITC) and a series of isothiocyanates structurally related to polynuclear aromatic hydrocarbons: 9-phenanthryl isothiocyanate (9-PhenITC), 9-phenanthrylmethyl isothiocyanate (9-PhenMeITC), 6-chrysenyl isothiocyanate (6-ChrysITC) and 6-benzo[a]pyrenyl isothiocyanate (6-BaPITC). None of the isothiocyanates inhibited tumor development by BaP, and three of them--PHITC, 9-PhenITC and 9- PhenMeITC--enhanced skin tumor multiplicity. Taken together with available literature data, the results of this study suggest that different isothiocyanates selectively inhibit cytochrome P450 enzymes involved in the metabolic activation or detoxification of BaP and therefore have differing effects on BaP tumorigenesis.

Animals↗
PubMed1993

Mutagenic peroxides in diethyl ether.

Concentration of water-saturated commercial samples of diethyl ether by a stream of nitrogen yielded an aqueous residue mutagenic in S. typhimurium strains TA100 and TA102, but not TA1535. Reverse phase high-performance liquid chromatography resolved the mixture into 4 UV absorbing peaks, each of which was positive for peroxide and mutagenic in strain TA100 and TA102. One of these was identified as H2O2 based on HPLC retention time and sensitivity to decomposition by catalase, and another as 1-ethoxyethylhydroperoxide, based on its 1H-NMR spectrum. The mutagenic peroxides appeared to be stable in water between pH 3 and 6, but unstable above pH 7; they were less stable in methanol, acetonitrile, and least stable in chloroform, in which they partially decomposed after 24 h at 20 degrees C. Generalization of the results suggests that adverse effects observed in vitro and in vivo with chemicals containing ether linkages that actually have been caused by contaminant peroxides and reactive oxygen compounds.

Chromatography, High Pressure Liquid↗
PubMed1993

Subtractive immunization yields monoclonal antibodies that specifically inhibit metastasis.

Subtractive immunization allowed the isolation and characterization of monoclonal antibodies that specifically inhibit metastasis but not proliferation of highly metastatic human tumor cells. The tolerizing agent cyclophosphamide was used to suppress the immune system in mice to dominant immunodeterminants present on a non-metastatic variant (M-) of the human epidermoid carcinoma cell line (HEp3). Mice were then inoculated with a highly metastatic variant (M+) of HEp3 to enhance an immune response to antigenic determinants present on metastatic cells. Hybridomas were generated and screened by ELISA for differential reactivity to M+ HEp3 over M- HEp3 cells. This experimental approach, termed subtractive immunization (S.I.), was compared to a control immunization protocol, which eliminated the cyclophosphamide treatment. The S.I. protocol resulted in an eight-fold increase in the proportion of mAbs that react with molecules enriched on the surface of the M+ HEp3 cells. Two of the mAbs derived from the S.I. protocol, designated DM12-4 and 1A5, were purified and examined for their effect in a metastasis model system in which chick embryos are transplanted with primary HEp3 tumors. Purified mAbs DM12-4 and 1A5, inoculated i.v. into the embryos, inhibited spontaneous metastasis of HEp3 cells by 86 and 90%, respectively. The mAbs are specifically anti-metastatic in that they have no effect on the growth of HEp3 cells in vitro nor did they inhibit primary tumor growth in vivo. The mAbs recognize M+ HEp3 cell surface molecules of 55 kD and 29 kD, respectively. These data demonstrate that the S.I. protocol can be used for the development of unique mAbs that are reactive with antigenic determinants whose expression is elevated on metastatic human tumor cells and which function mechanistically in the metastatic cascade.

Adenocarcinoma↗
PubMed1993

Evaluation of the anti-inflammatory and liver-protective effects of anoectochilus formosanus, ganoderma lucidum and gynostemma pentaphyllum in rats.

The pharmacological effects of Anoectochilus formosanus, Ganoderma lucidum and Gynostemma pentaphyllum were studied against carrageenan-induced paw edema and CC1(4)-induced hepatotoxicity in rats. The water extracts of G. pentaphyllum and G. lucidum were found to possess significant anti-inflammatory activity against carrageenan induced edema. The administration of Gynostemma pentaphyllum displayed an activity even more potent than indomethacin. In contrast, Anoectochilus formosanus showed a delayed onset of anti-inflammatory activity starting from 4 hrs post carrageenan administration. However, A. formosanus significantly decreased the acute increase in serum GOT and GPT level caused by CC1(4). Histological changes such as necrosis, fatty change, ballooning degeneration, inflammatory infiltration of lymphocytes and Kupffer cells around the central vein were simultaneously improved by the treatment of A. formosanus.

Alanine Transaminase↗
PubMed1992

Methylations of 70,000-Da heat shock proteins in 3T3 cells: alterations by arsenite treatment, by different stages of growth and by virus transformation.

We have characterized the basic amino acid methylation of three members of the 70,000-Da heat shock protein superfamily, hsp68, hsc70, and BiP, in Balb/c 3T3 cells. It appears that a lysyl residue is the only methylation site in BiP and that both lysyl and arginyl residues are methylated in hsp68 and hsc70. In all cases, epsilon-N-trimethyllysine is the predominant methyllysine species. Both NG-monomethylarginine and NG,NG-dimethylarginine are identified as the methylarginine species. The stoichiometry of the methylation is indirectly determined by using the amount of actin methylation as a reference. Three, four, and four methyl groups are incorporated into lysyl residues of hsp68, hsc70, and BiP, respectively. The level of lysyl methylation in hsc70 remains unchanged under different growth conditions. On the other hand, the arginyl methylation in hsc70 varies considerably. In confluent Balb/c 3T3 cells, there are 1.8 and 1.3 methyl groups in dimethylarginine and monomethyl-arginine, respectively. In nonconfluent cells, the amount of monomethylarginine is similar to that in confluent cells, but dimethylarginine is not detectable. Furthermore, in both confluent and nonconfluent cells, the level of monomethylarginine is reduced 5- to 10-fold after arsenite treatment. However, in 3T3 cells transformed by Rous sarcoma virus (SR-RSV 3T3 cells), the level of arginine methylation is constitutively lower and cannot be reduced further by arsenite.

3T3 Cells↗
PubMed1992

Studies on folk medicine "thang-kau-tin" from Taiwan. (I). The anti-inflammatory and liver-protective effect.

Five species of crude drugs are used as "Thang-kau-tin" on Taiwan market: (1) the stem of Mallotus repandus (Willd.) Muell.-Arg, (2) the stem and root of M. repandus (Willd.) Muell.-Arg, (3) the stem of Bauhinia championii Benth, (4) the stem with hooks of Uncaria hirsuta Haviland and (5) the stem with hooks of U. rhynchophylla Miquel. To clarify the effect of these crude drugs as anti-inflammatory and liver-protective agents, studies were conducted on water extracts of these five crude drugs. The statistical analysis (ANOVA) indicated that the stem of M. repandus showed the best anti-inflammatory activity against the paw edema induced by carrageenan. Nevertheless, the acute increase of GOT and GPT levels caused by CCl4 were markedly decreased by the treatment of M. repandus (stem), B. championii and U. hirsuta as a recipe group. The pathological changes around the central vein including fatty change, ballooning degeneration, cell necrosis, the increase in lymphocytes and Kupffer cells were improved by the treatment with the group of crude drugs as mentioned above.

Alanine Transaminase↗
PubMed1992

The pharmacological and pathological studies on Taiwan folk medicine (VIII): The anti-inflammatory and liver protective effects of "mu-mien".

The bark, xylem of stem, and root of (1) Bombax malabarica DC. and (2) Ceiba pentandra GAERTN. are marked as "Mu-mien" in Taiwan. In order to clarify the pharmacological effects of these three parts, anti-inflammatory and liver protective effect were evaluated with carrageenan-induced paw edema and CCl4-induced hepatotoxicity in rats. The statistical analysis (ANOVA) shows that all of the treatment used exhibited significant anti-inflammatory activity against carrageenan-induced edema. Furthermore, the administration of root and xylem of stem of B. malabarica showed the activity even better than indomethacin group did. However, only three used parts of B. malabarica significantly alleviated liver injury induced by CCl4. Meanwhile, the histological changes in rat hepatic tissues such as fatty change, ballooning degeneration, cell necrosis, lymphocytes and Kupffer cells were also observed.

Animals↗
PubMed1992

[The role of total gastrectomy in the management of gastrinoma syndrome].

Total gastrectomy used to be considered as a standard operation in the surgical treatment for gastrinoma syndrome. Although this end organ resection is a good palliation, to cure this ulcerogenic disease, gastrinoma resection is preferred. It remains a question if a total gastrectomy is necessary when a gastrinoma is found and resected. In a period of 12 years, nine out of 17 patients with gastrinoma syndrome were surgically treated. Fifteen gastrinomas were removed without histologic evidence of malignancy. Total gastrectomy was added in three, Whipple's operation was done in one and tumor resection alone in five. Serial examination of the resected stomach didn't find any gastrinoma. Eight gastrinomas of seven patients were found located in the pancreas, duodenum and lymph nodes within the gastrinoma triangle. These patients except one were followed up for six months to five years (mean 32 months). One died of post-operative hepatic failure, and one died of hypophysectomy for a co-existent huge prolactinoma (MEN I) four years later. Cure of the disease in terms of normal fasting serum gastrin levels, symptom free without medication, endoscopic evidence of healed ulcer, and a negative conversion of secretin provocative test was found in 2/3 of the patients with additional total gastrectomy, and 4/6 of the others. All cured patients had their gastrinomas located in the gastrinoma triangle, and six of the seven (85.7%) patients with gastrinomas in the triangle were cured. It is our conclusion that total gastrectomy was retrospectively unnecessary in most of the patients with gastrinomas in the gastrinoma triangle. Staged operations should be planned.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Effects of subgingival antimicrobial irrigation in chronic periodontitis--clinical observation].

One week prior to the establishment of baseline records, 144 sites with a probing pocket depth of 5-7 mm in 13 periodontitis patients were treated with plaque control and root planning. Sites with periodontitis involvement in each patient were divided, by split mouth design, into 4 quadrants. Each quadrant was irrigated subgingivally with either 0.05% metronidazole or 0.05% ornidazole, or 0.2% chorhexidine, or 0.9% normal saline (control) once every 2-3 days for 4 weeks. The plaque index, sulcus bleeding index, probable pocket depth and gingival index were assessed at the baseline and at 4 weeks, 8 weeks and 12 weeks following initial preparation. All 4 clinical parameters in the ornidazole treated group showed significant improvement as compared with baseline values, but the improvements were not maintained to the end of the study. Except for improvement in the sulcus bleeding index and the gingival index in the ornidazole group, which was superior to that of the metronidazole group at the 4th week, there were no significant differences in other parameters between the ornidazole, metronidazole and chlorhexidine groups at the irrigation sites. From these data we can tentatively conclude that subgingival irrigation with ornidazole in deep pockets is more effective than metronidazole or chlorhexidine in nonsurgical periodontal therapy.

Adult↗
PubMed1989

Manganese induced parkinsonism: an outbreak due to an unrepaired ventilation control system in a ferromanganese smelter.

Several cases of parkinsonism were found in a ferromanganese smelter after the ventilation system had broken down and had not been repaired for eight months in 1985. To determine the aetiology and prevalence of parkinsonism, 132 workers were submitted to thorough medical examination and estimated air concentrations of carbon monoxide and manganese at different worksites. Only six of eight workers performing electrode fixation or welding during 1985 developed parkinsonism. They were exposed for 30 minutes each day, seven days a week, to high concentrations of air manganese (greater than 28.8 mg/m3). There was a consistent trend between the index of exposure to manganese and signs and symptoms exhibited by extrapyramidal systems. After repair of the ventilation system, the air concentration of manganese during electrode fixation and welding decreased to less than 4.4 mg/m3; furthermore, no new cases of parkinsonism have been observed. Workers with parkinsonism recovered partially after removal from original worksites and treatment with levodopa. It is concluded that the outbreak resulted from exposure to high concentrations of manganese fumes through the breakdown of the ventilation system.

Adult↗
PubMed1988

Occupational asthma due to toluene diisocyanate among velcro-like tape manufacturers.

During September-November, 1985, four employees of a factory were seen at the occupational clinic complaining of cough, shortness of breath, and wheezing. All four worked in the same area of the factory where an adhesive containing toluene diisocyanate (TDI) was applied to velcro-like tape during manufacturing. To confirm the diagnosis of TDI-induced asthma and determine the prevalence among workers, 38 workers were interviewed and examined (84%) in the factory. Air samples were also taken from several areas in the factory to determine the TDI concentration. For analysis, the factory was divided into three areas based on the concentration of TDI: low (0.012 +/- 0.002 ppm), medium (0.021 +/- 0.006 ppm), and high (0.047 +/- 0.054 ppm). The distribution of workers with symptoms of asthmatic bronchitis was highly associated with TDI concentration (p less than 0.001). After stopping work for a period of 10 days, workers in areas with a high concentration of TDI showed marked improvement in pulmonary function tests (PFTs). After isolation of the exposure site, improvement of the ventilation system, and substitution of the TDI with less volatile diphenylmethane diisocyanate (MDI), air concentration of isocyanates was usually below 0.007 ppm. Three of the four clinically overt asthma cases went back to work without any difficulty. The PFTs of affected workers showed a significant improvement 5 months later. We conclude that TDI was responsible for the occupational asthma among velcro-like tape manufacturers and that the TDI-induced impairment of pulmonary functions was at least partially reversible.

Adhesives↗