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K W Lin

Publications and source records attributed to K W Lin.

14 recordsLinked to original sources
PubMed2005

Ethnobotanical study of medicinal plants used by the Jah Hut peoples in Malaysia.

CONTEXT: An ethnobotanical study was carried out among the Jah Hut people who live in the central part of peninsular Malaysia. MATERIALS AND METHODS: The information on the medicinal plants was obtained from interview with a traditional medicinal man. The traditional uses and remedies were documented. The literature searches were carried out for the evaluation on the current status of investigations on these plants. RESULTS: In this study, we present 16 species of plants, which are commonly used among the Jah Hut people to cure some common diseases. DISCUSSION: This study is important to preserve the knowledge of medicinal plants used by Jah Hut people. The surveys of phytopharmacological literatures of these plants have great pharmacological and ethnobotanical significance.

Ecology↗
PubMed2000

Dietary oxidized oil influences the levels of type 2 T-helper cell-related antibody and inflammatory mediators in mice.

The aim of this present study was to investigate the effect of amount and degree of oxidation of dietary oil on type 2 T-helper cell (TH)-related immune responses. Four groups of BALB/c mice were fed either 50 g soyabean oil/kg (50-S), 50 g oxidized oil/kg (50-O), 150 g soyabean oil/kg (150-S) or 150 g oxidized oil/kg (150-O). After 14 weeks consuming the experimental diets, the mice were immunized with ovalbumin (OVA) plus Al and antigen-specific immunoglobulin (Ig)E, IgG1 and IgG2a, inflammatory mediators such as prostaglandin (PG) E2 and leukotriene (LT)B4 were determined. Higher hepatic microsomal cytochrome P450 was noted in mice fed 150 g oxidized oil/kg compared with those of other groups. OVA-specific IgG1 and IgE were higher in mice fed 150 g oxidized oil/kg compared with those of the other groups. The data suggested the interleukin (IL)-4: interferon (IFN)-gamma ratio was higher in mice fed 50 g dietary oxidized oil/kg compared with that of the 50-S group. The IL-5:IFN-gamma ratios were higher in the 150-S and 150-O groups than in the 50-S and 50-O groups. PGE2 and LTB4 produced by macrophages stimulated by lipopolysaccharide were highest in mice in the 150 g oxidized oil/kg group. The data suggested that an increased intake of oxidized oil might exert an unfavourable effect on the TH2 response involved in allergic disease.

Animals↗
PubMed1999

Identification of core sequences involved in metabolism-dependent nuclear protein binding to the rat insulin-like growth factor I gene.

In the liver, most insulin-like growth factor I (IGF-I) transcripts originate in exon 1, where important cis-regulatory regions are located downstream from the major transcription initiation sites. Within these regions, we have attempted to identify sequences which are involved in the decrease in IGF-I gene transcription associated with diabetes mellitus. The function of different genomic templates was assessed by in vitro transcription, which revealed a consistent 50-80% decrease in the activity of nuclear extracts from streptozotocin-diabetic as compared with normal rats. The disparity in transcriptional activity between normal and diabetic nuclear extracts was reduced with templates containing 11-bp mutations within DNase I protected regions III or V (+42 and +129 bp, respectively, from the major transcription initiation site), but a mutation between regions IV and V had little effect. Within region III, gel mobility shift analysis and methylation interference studies indicated that DNA-protein interactions involve a GCGC core sequence. In region V, gel mobility shift studies and uracil interference analysis revealed interactions involving a TTAT core. While gel mobility shift analysis and transient transfection studies indicate that the GCGC core sequence in region III recognizes C/EBP, the AT-rich sequence in region V is likely to recognize a protein with homeodomain characteristics. Identification of the nuclear factor(s) interacting with regions III and V, downstream from exon 1 initiation sites, will be important for understanding the mechanism of reduced IGF-I gene transcription due to diabetes mellitus.

Animals↗
PubMed1999

[Inhibition of gastric myoelectric activity and gastric motility by microinjection of substance P into dorsal vagal nucleus in rats].

The present investigation showed that microinjection of substance P (SP) into dorsal vagal nucleus inhibited gastric myoelectric fast wave and gastric motility. The effect could be blocked by SP antiserum or SP antagonist [Arg6, D-Trp7,9, N-Me-Phe8]-SP6-11 or vagotomy. Depletion of sympathetic transmitters by reserpine did not affect induction of the inhibition. The results indicate that both exogenous and endogenous SP of dorsal vagal nucleus decrease the gastric myoelectric fast wave and motility, which is mediated by vagus nerve.

Animals↗
PubMed1996

In vitro transcription of the rat insulin-like growth factor-I gene.

Although the liver is the major source of circulating insulin-like growth factor-I (IGF-I), relatively little is known about the regulation of IGF-I gene transcription in this tissue. Since transcripts are initiated largely in exon 1, we established an in vitro transcription system to evaluate activation of transcription via the major exon 1 initiation site. Transcription of a G-free cassette reporter was directed by rat IGF-I genomic fragments, and the adenovirus major late promoter was used as an internal control. Tissue specificity was demonstrated by a 60-90% decrease in transcripts with spleen extracts as compared with liver. 54 base pairs (bp) of upstream sequence were sufficient to direct IGF-I gene transcription, and activity increased 5-fold with 300 bp of upstream sequence. DNase I footprinting revealed four protected regions between -300 and -60 bp; binding was confirmed by gel shift analysis, and tissue specificity was demonstrated by reduced shifts with spleen extracts. The necessity of transcription factor binding to such sites was established by competition analysis, which revealed a specific decrease in IGF-I transcription in the presence of a competing fragment. Use of this in vitro transcription system should permit analysis of the function of individual transcription factors involved in regulation of IGF-I gene expression.

Animals↗
PubMed1996

[Inhibitory effect of substance P of caudate nucleus on gastric motility via substantia nigra and dorsal vagal nucleus mediated by vagus nerve].

Effects of lesion of bilateral hypothalamus (LH), substantia nigra and dorsal vagal nucleus as well as their efferent pathway on the inhibition of gastric myoelectric fast wave and gastric motility due to injection of substance P (SP) to caudate nucleus were studied in rats. The experimental results showed that this induced inhibition was independent of the presence of intact LH but abolished by lesioning substantia nigra, dorsal vagal nucleus or vagus nerve. Depletion of sympathetic transmitter by reserpine did not affect the occurrence of the inhibition. Thus, it appears that the gastric inhibitory effect of caudate nucleus SP is mediated via substantia nigra and dorsal vagal nucleus to vagus nerve.

Animals↗
PubMed1995

Transcriptional regulation of the rat insulin-like growth factor-I gene involves metabolism-dependent binding of nuclear proteins to a downstream region.

Insulin-like growth factor-I (IGF-I) gene transcription is mediated largely via exon 1. In an initial search for regulatory regions, rat hepatocytes were transfected with IGF-I constructs. Since omission of downstream sequences led to reduced expression, we then used in vitro transcription to evaluate potential metabolic regulation via downstream regions. With templates including 219 base pairs of downstream sequence, transcriptional activity was reduced 70-90% with hepatic nuclear extracts from diabetic versus normal rats. However, activity was comparable with templates lacking downstream sequences. The downstream region contained six DNase I footprints, and templates with deletion of either region III or V no longer provided reduced transcriptional activity with nuclear extracts from diabetic rats. Nuclear protein binding to regions III and V appeared to be metabolically regulated, as shown by reduced DNase I protection and activity in gel mobility shift assays with nuclear extracts from diabetic rats. Southwestern blotting probes corresponding to regions III and V recognized a approximately 65-kDa nuclear factor present at reduced levels in diabetic rats. These findings indicate that a downstream region in exon 1 may be important for both IGF-I expression and metabolic regulation. Altered concentration or activity of a transcription factor(s) binding to this region may contribute to reduced IGF-I gene transcription associated with diabetes mellitus.

Animals↗
PubMed1995

[Participation of dopamine on the muscarinergic inhibitory effect of substance P on gastric myoelectric activity and motility].

Our previous study showed that microinjection of substance P (SP) into caudate nucleus inhibits gastric myoelectric fast wave and gastric motility, an effect mediated by muscarinic receptor. The present investigation showed that this effects of SP could be blocked by coinjected SP antiserum or SP antagonist [Arg6, D-Trip7,9, MePhe8]-SP6-11 or D2 dopamine antagonist haloperidol. In addition, microinjection of dopamine (DA) into caudate nucleus could also inhibit gastric fast wave and motility, an effect again being blockable by coinjected DA antagonist haloperidol or atropine. Thus, it appears that the muscarinergic inhibitory effect of SP on gastric fast wave and motility is mediated by D2 dopamine receptor.

Animals↗
PubMed1994

[Effect and its mechanism of substance P on contractile activity of isolated antral muscle strips of rat].

The present study was aimed at investigating the effect of substance P (SP) on the contractile activity of isolated antral muscle strips of rat and its underlying mechanism. Isolated strips were incubated in an organ bath into which SP was added with or without pretreatment of some antagonists or inhibitors. The results were as follows: (1) SP increased the contractile amplitude of the strips in a dose-dependent manner from 8 x 10(-11) to 8 x 10(-7) mol. At 4 x 10(-8) mol the amplitude was increased by 160.9 +/- 23.0%, while the automaticity of the strips was not affected. (2) This effect of SP could be partially inhibited by hexamethonium (ganglionic blocker), cyproheptadine (blocker of 5-HT2 receptor), diphenhydramine (blocker of H1 receptor), or aminophylline (inhibitor of phosphodiesterase), but not by atropine, propranolol, phentolamine, haloperidol, or naloxone. These results suggested that SP might be a non-cholinergic excitatory transmitter. Its spasmogenic action might be mediated by activating 5-HT neurons, which elicited release of histamine or directly acted on muscle cells.

Animals↗
PubMed1994

[Inhibition of gastric myoelectric activity and gastric motility induced by microinjection of substance P into caudate nucleus in mouse].

Changes of gastric myoelectric fast wave, slow wave and gastric motility were studied after microinjection of substance P or ACh into caudate nucleus in an attempt to find the interaction between the two substances. Gastric myoelectric activity and motility were recorded by a RM-6200 four channel recorder and then delivered to a IBM-PC computer for analysis. After microinjection of SP or ACh into caudate nucleus, the gastric myoelectric fast wave and gastric motility were significantly suppressed, while the slow wave was not significantly changed.

Animals↗
PubMed1992

Microcomputer-aided system for electrocardiograms and blood pressure analysis during drug-induced transient periods.

In the current experiments, we have developed a microcomputer-aided system for amplitude and duration parameter analysis of electrocardiogram (ECG) and blood pressure (BP) waveforms during the drug-induced transient period. Both ECG and BP are monitored, amplified and recorded using standard techniques. For studying the parameter variation trend, the time course of each parameter was produced. Based on these requirements, the present system combined data acquisition, data selection, data analysis, graph plotting and some experimental techniques to meet the need. Generalized human ECG and arterial BP waveforms were used in this system to expand its usable ranges. From the time course graph plotting, the variation trend of each parameter during each drug-induced transient period was obtained thereafter. The main advantages of this system include: (1) transient analysis--the system is suitable for complete and precise parameter analysis of human and animal ECG and BP in the drug-induced transient period; (2) ease of construction--the simplified hardware interface and IBM PC-AT compatible system make this system easy to be constructed; (3) ease of operation--modular data acquisition, processing and analysis procedures make this system easy to be operated; (4) high expansion potential--the modular hardware interface and modular software procedure make this system easy to be expanded; (5) wide utility--the system can be applied to any other research areas which involve the parameter analysis of ECG and BP.

Animals↗
PubMed1992

Effects of adrenoceptor agonists and antagonists on cardiovascular functional parameters in rats.

The effects of intravenous administration of adrenoceptor agonists and antagonists on electrocardiographic or blood pressure (BP) functional parameters were assessed in urethane-anesthetized rats. The responses of cardiovascular functional parameters produced by these drugs included: (1) isoproterenol decreased the duration of a whole BP cycle (Wd), duration of the diastolic wave (Dd), peak amplitude of the systolic wave (SYa), amplitude of the diastolic notch (DNa), amplitude of the diastolic wave (DWa), pulse pressure (dp) and mean arterial pressure (mp) but increased the heart rate (HR) accompanied by prolonged R-R (RR) or P-P interval (PP) (2) propranolol decreased SYa, DNa, dp, mp, HR, the amplitude of the P wave (Pa) and amplitude of the S wave (Sa) but increased the duration of the QRS wave, P-R interval, duration of the R wave (Rd) and duration of the P wave (Pd); (3) adrenaline decreased HR (accompanied by prolonged RR and PP), Rd, Pa and amplitude of the T wave (Ta) but increased Pd, Wd, Dd, DNA, the time interval between aortic valve opening and closure (Dw), dp, mp, amplitude of the Q wave and amplitude of the R wave (Ra); (4) noradrenaline decreased HR (accompanied by prolonged RR and PP) and Pa but increased Wd, Pd, SYa, DNa, Dw, dp, mp, Ra and Ta; (5) phenylephrine decreased HR (accompanied by prolonged RR and PP) and Pa but increased Wd, Dd, DNa, mp and Ra; (6) phentolamine decreased SYa, DNa, DWa, Dw, dp and mp. This study illustrates the utility of the automated electrocardiogram (ECG) and BP analysis system for investigation of adrenoceptor agonists and antagonists. The use of this methodology not only reproduced most of cardiovascular functional parameter effects produced by these drugs using the conventional methodology but also realizes some new information about the drug-induced ECG or BP waveform effects.

Adrenergic alpha-Agonists↗
PubMed1991

[Effect of bile salt in duodenum on gastric myoelectric activity and motility of mouse with a preliminary study of its neuromechanism].

Changes of gastric myoelectric fast wave, slow wave and gastric motility were studied after intraduodenal infusion of sodium taurocholate (ST) in an attempt to search the concerned neuromechanism. Frequency and total amplitude of the fast wave and slow wave of gastric myoelectric activity and of gastric contractile wave were recorded every five minutes before and after intraduodenal infusion of ST under the background action of various drugs. The frequency and amplitude were expressed in percentage change of the respective premedication value. After intraduodenal infusion of ST (n = 10) the frequency and the amplitude of fast wave and gastric contractile wave were suppressed. Blocking anesthesia of celiac plexus, reserpinization and intravenous infusion of carbachol could eliminate the inhibition induced by ST, which could be partly eliminated by intravenous infusion of propranolol but not affected by phentolamine at all. The results demonstrate that intraduodenal infusion of bile salt suppresses the fast wave of gastric myoelectric activity and gastric motility, most probably controlled by efferent sympathetic adrenergic fibres through beta-receptor.

Animals↗