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Fulltext Depressant action of an extract of Vernonia cinerea

Muir CK

Med J Malaysia, 1981 Jun;36(2):119-21.
PMID: 7201065

The effect of an aqueous extract of Vernonia cinerea (VX) on mice was determined. It is suggested that VX contains a depressant agent whose primary effect is that of analgesia.

Matched MeSH terms: Reaction Time/drug effects
Cognitive evoked potential (P300): a metric for cerebral concussion

Pratap-Chand R, Sinniah M, Salem FA

Acta Neurol. Scand., 1988 Sep;78(3):185-9.
PMID: 3227804

Cognitive impairment has been reported to occur in minor head injury (concussion). The value of the P300 evoked potential as a measure of cerebral concussion was studied in 20 patients with minor head injury and compared with the data from 20 normal subjects. Significant abnormalities of the P300 latency and amplitude were noted in these patients in the post-concussion period. The abnormalities improved completely on repeat testing. The correlation of the P300 to other parameters of head injury is discussed. The P300 constitutes a simple laboratory test that is sensitive measure of cerebral dysfunction in concussive head injuries.

Matched MeSH terms: Reaction Time/physiology
Chloroquine polymeric membrane electrodes: Development and applications

Saad B, Kanapathy K, Ahmad MN, Hussin AH, Ismail Z

Talanta, 1991 Dec;38(12):1399-402.
PMID: 18965315

Three main types of PVC solvent polymeric membrane ion-selective electrodes for chloroquine are described. They are based on three ion-pairing agents namely dipicrylamine (DPA), tetraphenylborate (TPB) or tetrakis(4-chlorophenyl)borate (TCPB) with either dioctylphenyl phosphonate (DOPP) or trioctyl phosphate (TOP) solvent mediator. All electrodes exhibit Nernstian responses, fast dynamic response times and a wide useful pH range. The best all-round electrode is based on TPB and TOP plasticizing solvent mediators with a limit of detection of 7.1 x 10(-6)M and was utilized for the assay of chloroquine in tablets. Direct potentiometric determinations with either the analyte addition method or the normal calibration method gave results comparable to the official method.

Matched MeSH terms: Reaction Time
A lead(II) ion selective electrode via a metal complex of poly(hydroxamic acid)

Anuar K, Hamdan S

Talanta, 1992 Dec;39(12):1653-6.
PMID: 18965586

A new lead(II) electrode has been constructed with poly(hydroxamic acid) (PHXA) as the active material and silicone rubber as the supporting material. The electrode gave near Nerstian response over the concentration range 4 x 10(-5)-1 x 10(-2)M lead(II). The detection limit of the electrode is approximately 4 x 10(-6)M and the electrode works well in the pH range 4.5-6.0. The response time was 50-120 sec over the whole concentration range and the electrode has a working life of at least 4 weeks. Iron(III) severely poisoned the electrode membrane. Nickel(II) and mercury(II) gave very strong interference compared to copper(II), silver(I), cobalt(II), sodium(I), potassium(I), zinc(II) and cadmium(II) which gave some or little interference. Values determined with atomic absorption (AAS) and a commercial lead(II) electrode were in good agreement with those measured with the lead(II) electrode reported here.

Matched MeSH terms: Reaction Time
Reliability of measurement of muscle fiber conduction velocity using surface EMG

Harba MI, Teng LY

Front Med Biol Eng, 1999;9(1):31-47.
PMID: 10354908

Cross-correlating two surface EMG signals detected at two different locations along the path of flow of action potential enables the measurement of the muscle fiber average conduction velocity in those active motor units monitored by the electrodes. The position of the peak of the cross-correlation function is the time delay between the two signals and hence the velocity may be deduced. The estimated velocity using this technique has been observed previously to depend on the location of the electrodes on the muscle surface. Different locations produced different estimates. In this paper we present a measurement system, analyze its inherent inaccuracies and use it for the purpose of investigating the reliability of measurement of conduction velocity from surface EMG. This system utilizes EMG signals detected at a number of locations on the biceps brachii, when under light tension, to look for any pattern of variations of velocity as a function of location and time. It consists of a multi-electrode unit and a set of eight parallel on-line correlators. The electrode unit and the parallel correlators ensure that these measurements are carried out under the same physical and physiological conditions of the muscle. Further, the same detected signals are used in different measurement configurations to try to understand the reasons behind the observed variations in the estimated velocity. The results obtained seem to suggest that there will always be an unpredictable random component superimposed on the estimated velocity, giving rise to differences between estimates at different locations and differences in estimates with time at the same location. Many factors contribute to this random component, such as the non-homogeneous medium between the muscle fibers and the electrodes, the non-parallel geometry and non-uniform conduction velocity of the fibers, and the physical and physiological conditions of the muscle. While it is not possible to remove this random component completely from the measurement, the user must be aware of its presence and how to reduce its effects.

Matched MeSH terms: Reaction Time
Rapid urease test in the diagnosis of Helicobacter pylori infection

Rosaida MS, Goh KL

JUMMEC, 2000;5:11-16.

Many tests are available for the diagnosis of H. pylori infection. Broadly they can be divided into invasive- endoscopy biopsy based tests and non-invasive tests. Of the endoscopy biopsy based tests the rapid urease tests (RUT) have been found to be the most convenient, accurate and inexpensive tests and they have therefore been recommended by several consensus panels and working parties as the test of choice during endoscopy. Several RUTS are available; some are commercial: CLO test, Pyloritek, Helicobacter urease test, H. yylori test and others- "homemade". We strongly recommend the "homemade" 1 min rapid urease test using an unbuffered solution as originally described by Arvind et al. This test has been shown to be easy to prepare, inexpensive and accurate on field-testing. Several factors affect the accuracy of the RUT. The larger the size of biopsy samples, the quicker is the postive reaction time. With the CLO test, warming the tests to 37'C has also been shown to hasten the reaction time. The effect of blood on the RUT poses an important problem in testing. It is vitally important to determine the H. yylori status in patients with bleeding peptic ulcers as the recurrence of bleeding has been shown to be markedly reduced or virtually abolished with H. yylori eradication. While the results of studies have not been entirely consistent, it is likely that presence of blood does reduce the sensitivity of the RUT. It is therefore sensible that in patients with bleeding ulcers, the RUT should not be the sole endoscopy biopsy test used and that samples should also be taken for histological examination.

Matched MeSH terms: Reaction Time
Effect of various antagonists on the Channa striatus fillet extract antinociception in mice

Zakaria ZA, Sulaiman MR, Mat Jais AM, Somchit MN

Can J Physiol Pharmacol, 2005 Jul;83(7):635-42.
PMID: 16091789

The effects of an aqueous supernatant of haruan (ASH) (Channa striatus) fillet extract on various antinociception receptor system activities were examined using a mouse abdominal-constriction model. Mice that were pretreated with distilled water, s.c., followed 10 min later by administration of 25%, 50%, and 100% concentration ASH, s.c., produced a significant concentration-dependent antinociceptive activity (p < 0.001). Pretreatment with naloxone (0.3, 1.0, and 3.0 mg/kg body mass), 10 min before ASH administration, failed to block the extract antinociception. Pretreatment of the 100% concentration ASH with mecamylamine (5 mg/kg), pindolol (10 mg/kg), and haloperidol (1 mg/kg) also did not cause any significant change in its antinociception. However, pretreatment with atropine (5 mg/kg), bicuculline (10 mg/kg), phenoxybenzamine (10 mg/kg), and methysergide (5 mg/kg) were found to reverse ASH antinociception. Based on the above findings, the ASH is suggested to contain different types of bioactive compounds that act synergistically on muscarinic, GABAA, alpha-adrenergic, and serotonergic receptor systems to produce the observed antinociception.

Matched MeSH terms: Reaction Time/drug effects
Ambulance services at hospital universiti sains malaysia and hospital kota bharu: a retrospective study of calls

Shah Che Hamzah MS, Ahmad R, Nik Abdul Rahman NH, Pardi KW, Jaafar N, Wan Adnan WA, et al.

Malays J Med Sci, 2005 Jul;12(2):34-42.
PMID: 22605956

This retrospective study attempted to identify the pattern of ambulance calls for the past two years at the Hospital Universiti Sains Malaysia (HUSM) and Hospital Kota Bharu (HKB). This study will provide a simple method of acquiring information related to ambulance response time (ART) and to test whether it met the international standards and needs of the client. Additionally, this paper takes into account the management of emergency calls. This included ambulance response time, which was part of Emergency Medical Services (EMS) episode: onset of ART, which started when details like phone number of the caller, exact location of the incident and the nature of the main complaint had been noted. ART ended when the emergency team arrived at the scene of incident. Information regarding ambulance calls from the record offices of HUSM and HKB was recorded for the year 2001 and 2002, tabulated and analyzed. There was a significant difference in the total number of calls managed by HUSM and HKB in the year 2001. It was noted that 645 calls were managed by HUSM while 1069 calls were recorded at HKB. In the year 2002, however, HUSM led with 613 extra numbers of calls as compare to HKB with 1193 numbers of calls. The pattern of ambulance calls observed is thought to possibly be influenced by social activities like local festivities, school holidays and the seasons. Further, it is observed that no studies were previously undertaken to compare the ART at both the HUSM and HKB to that of the international standards. In fact, a literature review undertaken so far showed no similar studies have been done for the whole Malaysia.

Matched MeSH terms: Reaction Time
An optical biosensor for dichlovos using stacked sol-gel films containing acetylcholinesterase and a lipophilic chromoionophore

Wong FC, Ahmad M, Heng LY, Peng LB

Talanta, 2006 Jun 15;69(4):888-93.
PMID: 18970653 DOI: 10.1016/j.talanta.2005.11.034

An optical biosensor consisting of a chromoionophore (ETH5294) (CM) doped sol-gel film interfaced with another sol-gel film immobilized with acetylcholinesterase (AChE) was employed to detect the insecticide dichlorvos. The main advantage of this optical biosensor is the use of a sol-gel layer with immobilized CM that possesses lipophilic property. The highly lipophilic nature of the CM and its compatibility with the sol-gel matrix has prevented leaching, which is frequently a problem in optical sensor construction based on pH indicator dyes. The immobilization of the indicator and enzyme was simple and need no chemical modification. The CM layer is pH sensitive and detects the pH changes of the acetylcholine chloride (AChCl) substrate when hydrolyzed by AChE layer deposited above. In the absence of the AChE layer, the pH response of the CM layer is linear from pH 6 to 8 (R(2)=0.98, n=3) and it showed no leaching of the lipophilic chromoionophore. When the AChE layer is deposited on top, the optical biosensor responds to AChCl with a linear dynamic range of 40-90mM AChCl (R(2)=0.984, n=6). The response time of the biosensor is 12min. Based on the optimum incubation time of 15min, a linear calibration curve of dichlorvos against the percentage inhibition of AChE was obtained from 0.5 to 7mg/L of dichlorvos (17-85% inhibition, R(2)=0.991, n=9). The detection limit for dichlorvos was 0.5mg/L. The results of the analysis of 1.7-6.0mg/L of dichlorvos using this optical biosensor agreed well with a gas chromatography-mass spectrometry detection method.

Matched MeSH terms: Reaction Time
Development of prototype heterogeneous chitosan membrane using different plasticizer for glutamate sensing

Isa IM, Ab Ghani S

Talanta, 2007 Jan 15;71(1):452-5.
PMID: 19071326 DOI: 10.1016/j.talanta.2006.04.034

This paper describes the preparation of and experimentation undertaken by heterogeneous chitosan membrane as ion selective electrode for glutamate ion. The linearity response was obtained in the range of 1.0x10(-5) to 1.0x10(-1)M with a detection limit of 1.0x10(-6)M. The performance of the electrode was found in the pH range of 4.0-8.0 at temperature 25+/-3 degrees C. The response time was at 5-35s and was useful for a period of more than 4 months. The selectivity values towards some anions indicates good selectivity over a number of interfering anions. No significant improvement of membrane performance over additional of plasticizers such as 2-NPOE, BEHA and DOPP. The electrodes gave sufficient Nernstian responses with the exception of membrane with 2-NPOE.

Matched MeSH terms: Reaction Time
Amino acid and fatty acid composition of an aqueous extract of Channa striatus (Haruan) that exhibits antinociceptive activity

Zakaria ZA, Mat Jais AM, Goh YM, Sulaiman MR, Somchit MN

Clin Exp Pharmacol Physiol, 2007 Mar;34(3):198-204.
PMID: 17250639

1. The present study was performed in order to determine the amino acid and fatty acid composition of an aqueous extract of the freshwater fish Channa striatus, obtained by soaking (1:2, w/v) fresh fillets overnight in a chloroform:methanol (2:1, v/v) solvent, to elucidate the mechanism responsible for its antinociceptive activity and to clarify the relationship between the presence of the amino and fatty acids and the expected activity. 2. The aqueous extract was found to contain all amino acids with the major amino acids glycine, alanine, lysine, aspartic acid and proline making up 35.77 +/- 0.58, 10.19 +/- 1.27, 9.44 +/- 0.56, 8.53 +/- 1.15 and 6.86 +/- 0.78% of the total protein, respectively. 3. In addition, the aqueous extract was found to have a high palmitic acid (C16:0) content, which contributed approximately 35.93 +/- 0.63% to total fatty acids. The other major fatty acids in the aqueous extract were oleic acid (C18:1), stearic acid (C18:0), linoleic acid (C18:2) and arachidonic acid (C20:4), contributing 22.96 +/- 0.40, 15.31 +/- 0.33, 11.45 +/- 0.31 and 7.44 +/- 0.83% of total fatty acids, respectively. 4. Furthermore, the aqueous extract was demonstrated to possess concentration-dependent antinociceptive activity, as expected, when assessed using the abdominal constriction test in mice. 5. It is concluded that the aqueous extract of C. striatus contains all the important amino acids, but only some of the important fatty acids, which are suggested to play a key role in the observed antinociceptive activity of the extract, as well as in the traditionally claimed wound healing properties of the extract.

Matched MeSH terms: Reaction Time/drug effects
An Optical Biosensor based on Immobilization of Laccase and MBTH in Stacked Films for the Detection of Catechol

Abdullah J, Ahmad M, Heng LY, Karuppiah N, Sidek H

Sensors (Basel), 2007 Oct 11;7(10):2238-2250.
PMID: 28903224 DOI: 10.3390/s7102238

The fabrication of an optical biosensor by using stacked films where 3-methyl-2-benzothiazolinone hydrazone (MBTH) was immobilized in a hybrid nafion/sol-gelsilicate film and laccase in a chitosan film for the detection of phenolic compounds wasdescribed. Quinone and/or phenoxy radical product from the enzymatic oxidation ofphenolic compounds was allowed to couple with MBTH to form a colored azo-dye productfor spectrophometric detection. The biosensor demonstrated a linear response to catecholconcentration range of 0.5-8.0 mM with detection limit of 0.33 mM and response time of10 min. The reproducibility of the fabricated biosensor was good with RSD value of 5.3 %(n = 8) and stable for at least 2 months. The use of the hybrid materials of nafion/sol-gelsilicate to immobilize laccase has altered the selectivity of the enzyme to various phenoliccompounds such as catechol, guaicol, o-cresol and m-cresol when compared to the non-immobilized enzyme. When immobilized in this hybrid film, the biosensor response onlyto catechol and not other phenolic compounds investigated. Immobilization in this hybridmaterial has enable the biosensor to be more selective to catechol compared with the non-immobilized enzyme. This shows that by a careful selection of different immobilizationmatrices, the selectivity of an enzyme can be modified to yield a biosensor with goodselectivity towards certain targeted analytes.

Matched MeSH terms: Reaction Time
Fulltext Cardiopulmonary resuscitation : the short comings in Malaysia

Sheng CK, Zakaria MI, Rahman NH, Jaalam K, Adnan WA

Malays J Med Sci, 2008 Jan;15(1):49-51.
PMID: 22589616

This short review explores the current status of cardiopulmonary resuscitation in Malaysia and highlights some of the factors that have a negative impact on its rate of success. Absence of a unifying body such as a national resuscitation council results in non-uniformity in the practice and teaching of cardiopulmonary resuscitation. In the out-of-hospital setting, there is the lack of basic skills and knowledge in performing bystander cardiopulmonary resuscitation as well as using an automated external defibrillator among the Malaysian public. The ambulance response time is also a significant negative factor. In the in-hospital setting, often times, resuscitation is first attended by junior doctors or nurses lacking in the skill and experience needed. Resuscitation trolleys were often inadequately equipped.

Matched MeSH terms: Reaction Time
Effects of Gold Nanoparticles on the Response of Phenol Biosensor Containing Photocurable Membrane with Tyrosinase

Sharina AH, Lee YH, Musa A

Sensors (Basel), 2008 Oct 16;8(10):6407-6416.
PMID: 27873876

The role of incorporation of gold nanoparticles (50-130 nm in diameter) into a series of photocurable methacrylic-acrylic based biosensor membranes containing tyrosinase on the response for phenol detection was investigated. Membranes with different hydrophilicities were prepared from 2-hydroxyethyl methacrylate and n-butyl acrylate via direct photocuring. A range of gold nanoparticles concentrations from 0.01 to 0.5 % (w/w) was incorporated into these membranes during the photocuring process. The addition of gold nanoparticles to the biosensor membrane led to improvement in the response time by a reduction of approximately 5 folds to give response times of 5-10 s. The linear response range of the phenol biosensor was also extended from 24 to 90 mM of phenol. The hydrophilicities of the membrane matrices demonstrated strong influence on the biosensor response and appeared to control the effect of the gold nanoparticles. For less hydrophilic methacrylic-acrylic membranes, the addition of gold nanoparticles led to a poorer sensitivity and detection limit of the biosensor towards phenol. Therefore, for the application of gold nanoparticles in the enhancement of a phenol biosensor response, the nanoparticles should be immobilized in a hydrophilic matrix rather than a hydrophobic material.

Matched MeSH terms: Reaction Time
Normal motor nerve conduction studies using surface electrode recording from the supraspinatus, infraspinatus, deltoid, and biceps

Buschbacher RM, Weir SK, Bentley JG, Cottrell E

PM R, 2009 Feb;1(2):101-6.
PMID: 19627883 DOI: 10.1016/j.pmrj.2008.08.002

Proximal peripheral nerve conduction studies can provide useful information to the clinician. The difficulty of measuring the length of the proximal nerve as well as a frequent inability to stimulate at 2 points along the nerve adds a challenge to the use of electrodiagnosis for this purpose. The purpose of this article is to present normal values for the suprascapular, axillary, and musculocutaneous nerves using surface electrodes while accounting for side-to-side variability.

Matched MeSH terms: Reaction Time
Spatial memory performance of Wistar rats exposed to mobile phone

Narayanan SN, Kumar RS, Potu BK, Nayak S, Mailankot M

Clinics (Sao Paulo), 2009;64(3):231-4.
PMID: 19330250

INTRODUCTION: With the tremendous increase in number of mobile phone users world wide, the possible risks of this technology have become a serious concern.
OBJECTIVE: We tested the effects of mobile phone exposure on spatial memory performance.
MATERIALS AND METHODS: Male Wistar rats (10-12 weeks old) were exposed to 50 missed calls/day for 4 weeks from a GSM (900/1800 MHz) mobile phone in vibratory mode (no ring tone). After the experimental period, the animals were tested for spatial memory performance using the Morris water maze test.
RESULTS: Both phone exposed and control animals showed a significant decrease in escape time with training. Phone exposed animals had significantly (approximately 3 times) higher mean latency to reach the target quadrant and spent significantly (approximately 2 times) less time in the target quadrant than age- and sex-matched controls.
CONCLUSION: Mobile phone exposure affected the acquisition of learned responses in Wistar rats. This in turn points to the poor spatial navigation and the object place configurations of the phone-exposed animals.

Matched MeSH terms: Reaction Time
Antinociceptive activity of the essential oil of Zingiber zerumbet

Sulaiman MR, Tengku Mohamad TA, Shaik Mossadeq WM, Moin S, Yusof M, Mokhtar AF, et al.

Planta Med, 2010 Feb;76(2):107-12.
PMID: 19637111 DOI: 10.1055/s-0029-1185950

In the present study, the rhizome essential oil from Zingiber zerumbet (Zingiberaceae) was evaluated for antinociceptive activity using chemical and thermal models of nociception, namely, the acetic acid-induced abdominal writhing test, the hot-plate test and the formalin-induced paw licking test. It was demonstrated that intraperitoneal administration of the essential oil of Z. zerumbet (EOZZ) at the doses of 30, 100 and 300 mg/kg produced significant dose-dependent inhibition of acetic acid-induced abdominal writhing, comparable to that of obtained with acetylsalicylic acid (100 mg/kg). At the same doses, the EOZZ produced significant dose-dependent increases in the latency time in the hot-plate test with respect to controls, and in the formalin-induced paw licking test, the EOZZ also significantly reduced the painful stimulus in both neurogenic and inflammatory phase of the test. In addition, the antinociceptive effect of the EOZZ in the formalin-induced paw licking test as well as hot-plate test was reversed by the nonselective opioid receptor antagonist, naloxone suggesting that the opioid system was involved in its analgesic mechanism of action. On the basis of these data, we concluded that the EOZZ possessed both central and peripheral antinociceptive activities which justifying its popular folkloric use to relieve some pain conditions.

Matched MeSH terms: Reaction Time/drug effects
Antinociceptive activity of a synthetic chalcone, flavokawin B on chemical and thermal models of nociception in mice

Mohamad AS, Akhtar MN, Zakaria ZA, Perimal EK, Khalid S, Mohd PA, et al.

Eur J Pharmacol, 2010 Nov 25;647(1-3):103-9.
PMID: 20826146 DOI: 10.1016/j.ejphar.2010.08.030

The present study examined the potential antinociceptive activity of flavokawin B (6'-hydroxy-2',4'-dimethoxychalcone), a synthetic chalcone using chemical- and thermal-induced nociception models in mice. It was demonstrated that flavokawin B (FKB; 0.3, 1, 3 and 10 mg/kg) administered via both oral (p.o.) and intraperitoneal (i.p.) routes produced significant and dose-dependent inhibition in the abdominal constrictions induced by acetic acid, with the i.p. route producing antinociception of approximately 7-fold more potent than the p.o. route. It was also demonstrated that FKB produced significant inhibition in the two phases of the formalin-induced paw licking test. In addition, the same treatment of flavokawin B (FKB) exhibited significant inhibition of the neurogenic nociceptive induced by intraplantar injections of glutamate and capsaicin. Likewise, this compound also induced a significant increase in the response latency period to thermal stimuli in the hot plate test and its antinociceptive effect was not related to muscle relaxant or sedative action. Moreover, the antinociception effect of the FKB in the formalin-induced paw licking test and the hot plate test was not affected by pretreatment of non-selective opioid receptor antagonist, naloxone. The present results indicate that FKB produced pronounced antinociception effect against both chemical and thermal models of pain in mice that exhibited both peripheral and central analgesic activity.

Matched MeSH terms: Reaction Time/drug effects
Extraction of dynamic features from hand drawn data for the identification of children with handwriting difficulty

Khalid PI, Yunus J, Adnan R

Res Dev Disabil, 2010 Jan-Feb;31(1):256-62.
PMID: 19854613 DOI: 10.1016/j.ridd.2009.09.009

Studies have shown that differences between children with and without handwriting difficulties lie not only in the written product (static data) but also in dynamic data of handwriting process. Since writing system varies among countries and individuals, this study was conducted to determine the feasibility of using quantitative outcome measures of children's drawing to identify children who are at risk of handwriting difficulties. A sample of 143 first graders of a normal primary school was investigated regarding their handwriting ability. The children were divided into two groups: test and control. Ten children from test group and 40 children from control group were individually tested for their Visual Motor Integration skills. Analysis on dynamic data indicated significant differences between the two groups in temporal and spatial measures of the drawing task performance. Thus, kinematic analysis of children's drawing is feasible to provide performance characteristic of handwriting ability, supporting its use in screening for handwriting difficulty.

Matched MeSH terms: Reaction Time
Motorcyclist rear brake simple perception-response times in rear-end collision situations

Davoodi SR, Hamid H, Arintono S, Muniandy R, Faezi SF

Traffic Inj Prev, 2011 Apr;12(2):174-9.
PMID: 21469025 DOI: 10.1080/15389588.2010.533314

The purpose of this study was to determine the baseline motorcycle riders' perception-response times (PRTs) in an expected object braking task and to determine the significant difference between PRTs of older and younger riders.

Matched MeSH terms: Reaction Time*

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