Biomedical subjects
Publications and source records attributed to J M Lin.
Chronic atrial fibrillation can be eliminated by an atrial compartment operation, but additional partition on the right atrium impairs the recovery of right atrial mechanical function. Thus, it is important to appropriately divide the atria for both maintaining sinus rhythm and maximizing atrial mechanical function.
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The use of molecularly imprinted polymer polymerized in capillary for the separation of amino acid enantiomers by electrochromatography is described. The substrate-selective polymers were prepared by using L-phenylalanine anilide as print molecule and methacrylic acid and/or 2-vinylpyridine as the functional monomers, which is believed to interact both ionically and through hydrogen bonding with the print molecule. Several aspects of the polymer preparation were investigated, including the treatment of the inside surface of the capillary, the composition of the polymers and the running conditions of the capillary electrochromatography. Such separation was highly specific and depended on the presence of both the print molecule and the functional monomer in the polymerization mixture. This preliminary report demonstrates a novel and simple method for the development of the capillary electrochromatographic separation of amino acid enantiomers using molecularly imprinted polymer.
The expression of genes encoding conglutin gamma and a leginsulin-like protein has been examined in narrow-leafed lupin, Lupinus angustifolius L. Conglutin gamma is a homologue of basic 7S globulin (Bg), the insulin and leginsulin binding protein from soybean. Accumulation of conglutin gamma mRNA, as assessed by northern assays and reverse-transcription PCR, was tightly regulated both spatially and temporally in lupin plants and was detected almost exclusively in developing seeds. Similar tissue and temporal specificity was demonstrated when 1.8 kb of the promoter region from the conglutin gamma gene was used to drive the expression of a beta-glucuronidase reporter gene in transgenic plants. In stably transformed tobacco the conglutin gamma promoter produced strong, temporally regulated and seed-specific expression of the reporter gene which was localised to the embryo tissues and to a layer of cells adjacent to the seed coat. A truncated 0.29 kb promoter fragment produced much reduced levels of expression and a loss of embryo specificity. Leginsulin-like mRNA was similarly detected in lupins only in developing seeds. The leginsulin-like gene detected in L. angustifolius showed 96% sequence identity to leginsulin from soybean within the 280 bp region amplified from lupin by PCR. The results demonstrate that both components of a Bg-leginsulin putative signal transduction pathway are present in the seeds of lupin.
Interleukin-1 beta (IL-1 beta) is a potent regulator of osteoprogenitor cells and fibroblasts, and is believed to be responsible for the bone loss and connective tissue breakdown that occurs in periodontitis. Decorin, a major small proteoglycan in the periodontium, has been shown as an important mediator of the organization of the pericellular and extracellular matrix. Since the HPLF play a significant role in the regulation of extracellular matrix metabolism, it was important to clarify the causal relationship between cytokines, HPLF and proteoglycans. We investigated the effect of IL-1 beta on decorin gene expression and its functional regulation to elucidate the intracellular mechanism mediating the action of IL-1 beta. Quiescently confluent HPLF cultures were incubated for different treatment periods with various concentrations of IL-1 beta and/or 10(-4) M cycloheximide (Cx) in culture medium supplemented with 1% charcoal-stripped serum for different treatment periods. Northern hybridization analyses, using decorin cDNA probe, showed that IL-1 beta increased the abundance of decorin mRNA in both a dose- and time-dependent manner. Most of the stimulation was blocked by Cx, indicating that the regulation of decorin gene expression by IL-1 beta may be via an indirect pathway, requiring new protein synthesis which regulates the promoter. Gel mobility shift analyses detected the specific DNA binding activity of a nuclear extract of AP-1, but not NF-kappa B, that could bind to the recognition site of decorin gene promoter fragments with the increased abundance in IL-1 beta treatment groups. These results suggest that the increased transcription of decorin gene by HPLF in the presence of IL-1 beta is mediated at least in part through the interaction of AP-1 with the decorin gene promoter.
The free radical scavenging and antihepatotoxic activity from Terminalia catappa was studied. Treatment with T. catappa water extracts showed antihepatotoxic activity against CCl4-induced toxicity in the rat liver that was tested. The crude drug also exhibited anti-oxidant effects in FeCl2-Ascorbic acid induced lipid peroxidation in the rat liver homogenate. Moreover, the superoxide radical scavenger effect of T. catappa was demonstrated using electron spin resonance (ESR) and spintrapping technique. The results indicate that T. catappa possesses good antihepatotoxic activity and superoxide radical scavenger activity.
Persistent atrial standstill, characterized by absence of atrial activity on surface and intracavitary electrograms, absence of atrial mechanical activity, and inability to stimulate the atria electrically, is a rare disorder. Left atrial appendage blood flow has been reported to be related to P wave during sinus rhythm or local atrial electrogram during atrial fibrillation. However, distinct and periodical LAA blood flow was demonstrated in a patient with persistent atrial standstill by transesophageal echocardiography.
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Capillary gel electrophoresis (CGE) was successfully applied to the separation of optically active isomers and position isomers by incorporating a suitable cyclodextrin chiral selector in polyacrylamide gel. A commercially available ss-cyclodextrin (ss-CD) was used for enantioselectivity towards o-, m- and p-nitrobenzoic acid, o-, m- and p-hydroxybenzoic acid, o-, m- and p-toluic acid and the optical isomers of dansyl-D,L-leucine and R,S-1,1'-binaphthyl-2,2-dihydrogenphosphate. Especially the effect of organic solvents, such as acetonitrile, methanol, dimethylsulphoxide and others were examined in detail. The resolution varied to some extent with the addition of the organic solvent to the polyacrylamide gel and the running buffer solution. The possible mechanism has also been discussed. In addition, quantitative aspects of the separation of stereoisomers using CGE have been studied, showing that both the resolution and accuracy of the determinations were affected by the ratio of the enantiomers.
We investigated the change of the arterial-coronary sinus lactate difference before and after radiofrequency ablation to assess the influence of radiofrequency ablation on myocardial metabolism. Sixteen patients underwent radiofrequency catheter ablation and blood sampling. The patients were further divided into two groups according to the energy received, group 1 (n = 8) with lower energy and group 2 (n = 8) with higher energy. The postpacing arterial-coronary sinus lactate difference was significantly higher than that 1 min after ablation (0.18 +/- 0.16 vs. -0.08 +/- 0.14 mmol/l, P < 0.01). The mean arterial-coronary sinus lactate difference obtained at 3 min, 5 min and 10 min increased gradually and finally approximated the postpacing lactate difference. The arterial-coronary sinus lactate difference 1 min after ablation of group 2 was significantly lower than that of group 1 (-0.03 +/- 0.14 vs. -0.13 +/- 0.14 mmol/l, P < 0.01). The arterial coronary sinus lactate differences of group 2 obtained at 3 min, 5 min and 10 min were also lower than those of group 1. However, the difference between the two groups decreased with time. This finding suggests that radiofrequency energy has an influence on the myocardial metabolism and higher energy causes more metabolic alteration than lower energy.
4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a tobacco-specific, powerful, organospecific lung carcinogen. 4-Ipomeanol (IPO) is an investigational chemotherapeutic drug with specific toxicity towards the lung. We hypothesized that non-toxic analogs of IPO could be competitive inhibitors of the metabolic activation of NNK. We had shown previously that 4-hydroxy-1-phenyl-1-pentanone (HPP) and 7-hydroxy-1-phenyl-1-octanone (4-HPO) are effectively inhibiting the lung tumor activity of NNK in A/J mice. In these extended studies we have synthesized 11 new analogs of HPP and tested them for their in vitro activities as inhibitors of the metabolism of NNK. The present study demonstrated that the lipophilicity in the molecule is playing an important role for the inhibition of NNK metabolism with pulmonary and hepatic microsomes of A/J mice.
This study shows an increase in LAA flow after PTMV in both normal sinus rhythm and atrial fibrillation. These results suggest that relief of mitral stenosis may not only confer hemodynamic benefits for the improvement of symptoms but also have a favorable influence on future thromboembolism.
The free radical scavenging and antihepatotoxic activity from Ganoderma lucidum, Ganoderma formosanum and Ganoderma neo-japonicum were studied. Treatment with the water extract of Ganoderma lucidum, Ganoderma formosanum and Ganoderma neo-japonicum caused a marked decrease in the CCl4-induced toxicity in rat liver, made evident by their effect on the levels of glutamic oxaloacetic transaminase (GOT) and lactic dehydrogenase (LDH) in the serum. The scavenging potency of the water extracts of the crude drugs was evaluated in terms of their ability to reduce the peaks of spin adducts using electron spin resonance (ESR) spin-trapping techniques. The results indicated that Ganoderma formosanum showed the greatest antihepatotoxic activity and the greatest free radical scavenging activity.
Clinical decisions and controlled studies in regard to hypertension have long emphasized the casual diastolic blood pressure (DBP). The influence of superimposition of high systolic blood pressure (SBP) on the target organ damage has been less studied. To assess the role of isolated diastolic hypertension without interference of superimposition of systolic hypertension, 171 subjects with normal blood pressure, isolated diastolic hypertension (SBP < 140 and DBP > or = 90 mmHg) isolated systolic hypertension (SBP > or = 140 and DBP < 90 mmHg) or combined hypertension (SBP > or = 140 and DBP > or = 90 mmHg) determined by mean 24-h ambulatory blood pressure were compared in relation to target organ damage including ECG abnormality related to hypertension, cardiac enlargement by chest X-ray, proteinuria and retinopathy. The incidence of target organ damage was lower in subjects with normal BP than in the other three groups. The incidence of target organ damage was almost significantly higher in patients with isolated systolic hypertension than in those with isolated diastolic hypertension. No significant difference in the incidence of complications existed between patients with isolated systolic and combined hypertension. These findings demonstrate that the severity of hypertensive complications is more closely related to mean ambulatory SBP than mean ambulatory DBP. The level of systolic BP is important for predicting the severity of target organ damage in patients with high diastolic BP, because there is a significant difference in the incidence of target organ damage between isolated diastolic hypertension and combined hypertension.
The active oxygen species scavenging potencies of Mallotus repandus (Willd.) Muell.-Arg. extracts were evaluated by the electron spin resonance (ESR) spin-trapping technique. Superoxide radical (O2.-) and hydroxyl radical (OH.) were supplied enzymatically from hypoxanthine-xanthine oxidase (HPX-XOD) reaction and hydrogen peroxide-ferrous sulfate (Fenton reaction), respectively, to the assay system. The ethyl acetate fraction of Mallotus repandus (stem) showed the greatest superoxide radical scavenger activity and the n-hexane fraction of Mallotus repandus (stem as well as root) the greatest hydroxyl radical scavenger activity.
We examined the mammary carcinogenicity in CD rats of anti-2,3-dihydroxy-1,10b-epoxy-10b,1,2,3-tetrahydro-fluoranthene (FDE), a genotoxic metabolite of the environmental pollutant fluoranthene. FDE (2 mumol or 10 mumol) in 0.1 ml dimethyl sulfoxide (DMSO) was injected beneath each of the three left thoracic nipples of groups of 20 rats each, with 0.1 ml DMSO alone being injected under the right nipples. On the next day, the procedure was repeated for the three inguinal nipples on each side. anti-3,4-Dihydroxy-1,2-epoxy-1,2,3,4-tetrahydrobenzo[c]-phenanthrene (BcPDE, 2 mumol per nipple) was used as a positive control and DMSO alone as a negative control. Tumor development was assessed weekly by palpation and the experiment was terminated after 41 weeks. Eighty five percent of the rats in each of the FDE treated groups developed histologically confirmed mammary tumors, compared to 11% in the DMSO treated animals (P < 0.01). Most tumors were on the left side. The lower dose of FDE induced a significant number of adenomas while the higher dose induced significant incidences of both adenomas and adenocarcinomas compared to controls. BcPDE was a powerful mammary carcinogen, confirming our previous observation. The results of this study demonstrate the carcinogenicity of FDE to the CD rat mammary gland. Since FDE is a potentially transportable human metabolite of fluoranthene, its possible role as an etiologic factor in breast cancer deserves further study.
In blunt multiple trauma (MT) with head injury (HI) patients, it is difficult to decide whether to proceed with immediate laparotomy or craniotomy. In August 1989, abdominal ultrasonography (US) using a simple US scoring system was introduced for MT and HI patients as an initial rapid screening procedure. In MT and HI patients with a US score > or = 3 (n = 14), urgent laparotomy was the procedure of first choice. However, immediate head CT scan, then emergency craniotomy, may be justified in hemodynamically stable MT and HI patients with a US score < 3 (n = 98). Appropriate decision making can be applied to decide which procedure is most exigent.