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Biomedical subjects

A F Rahman

Publications and source records attributed to A F Rahman.

At least 19 recordsLinked to original sources
PubMed2003

Trends in inquiries on poisoning: a five-year report from the National Poison Centre, Malaysia.

This report describes inquiries relating to poisoning cases which were received by the National Poison Centre of Malaysia from the years 1996 to 2000. The study utilized data from the NPC report forms. Only data relating to patient contact with a poison or chemical were included in the analysis. The poison centre received an average of 186 poisoning inquiries per year. Doctors remained the highest group of caller to the poison centre throughout the five-year period. Nearly 50% of all inquiries was regarding pesticide poisoning and this trend remained constant during the five-year period. Overall, the findings showed that poisoning inquiries relating to patient care were lower than in Japan and the United States.

Adolescent↗
PubMed2002

Ultrasound measurement of the uterocervical angle before embryo transfer: a prospective controlled study.

BACKGROUND: The study aim was to determine whether moulding the embryo transfer catheter according to the uterocervical angle measured by ultrasound could improve pregnancy and implantation rates. METHODS: Patients were alternately allocated to one of two groups. In the ultrasound-guided group (n = 320), the catheter was moulded according to the uterocervical angle measured by abdominal ultrasound. In controls (n = 320), embryo transfer was performed using the "clinical feel" method. RESULTS: Moulding the embryo transfer catheter according to the uterocervical angle significantly increased clinical pregnancy [(OR = 1.57, 95% CI (1.08-2.27)] and implantation rates [(OR = 1.47, 95% CI (1.10-1.96)] compared with the "clinical feel" method. It also significantly reduced difficult transfers [(OR = 0.25, 95% CI (0.16-0.40)] and blood during transfers [OR = 0.71, 95% CI (0.50-0.99)]. Patients with large angles (>60 degrees ) had significantly lower pregnancy rates compared with those with no angle [OR = 0.36, 95% CI (0.16-0.52)]. CONCLUSIONS: Moulding the embryo transfer catheter according to the uterocervical angle measured by ultrasound increases clinical pregnancy and implantation rates and diminishes the incidence of difficult and bloody transfers.

Catheterization↗
PubMed1997

Therapeutic drug monitoring of gentamicin: a 6-year follow-up audit.

BACKGROUND AND OBJECTIVE: In 1984 a therapeutic drug monitoring (TDM) service was established in Hospital Universiti Sains Malaysia (HUSM) and gentamicin concentrations were measured and used to design optimal regimens for the antibiotic. In this study we report on a 6-year follow-up audit since our first assessment of the service. METHOD: Records of 733 requests for gentamicin monitoring were reviewed. RESULTS: Of the 592 patients involved, 39% were neonates and 42% were adults. Peak gentamicin concentrations were within the therapeutic range in 65% of the patients at first monitoring and 79% of the corresponding trough concentrations were within the non-toxic range. After dosage adjustment, 81% of the peak concentrations were within the therapeutic range and trough concentrations rose to levels regarded as toxic in 7% of patients. In patients with therapeutic peak concentrations at the first monitoring point, the average duration of gentamicin therapy was statistically shorter than in those patients who failed to achieve a therapeutic peak concentration. The distribution of gentamicin peak and trough concentrations in terms of therapeutic ranges were also better than those found in 1990. CONCLUSION: TDM for gentamicin is well accepted in HUSM and its application has contributed to improved gentamicin administration. Furthermore, our physicians are now able to choose more appropriate dosage regimens for their patients because the majority of gentamicin concentrations attained even at the first monitoring were within the therapeutic range.

Adult↗
PubMed1995

Role of GABAergic systems in the development of morphine tolerance in formalin-treated mice.

Since the development of tolerance to morphine antinociception in formalin-treated mice was delayed and diazepam normalized the delay, the involvement of GABAergic systems in the process was investigated. Gamma amino-n-butyric acid (GABA) at 10 mg/kg and the GABAA-receptor agonist muscimol at 0.05 mg/kg, i.p., 30 min before daily morphine injection at 10 mg/kg, s.c. completely reversed the delay in the development of morphine tolerance in the formalin-treated mice. The GABAA antagonist bicuculline at 1 mg/kg and the Cl(-)-channel blocker picrotoxin at 1 mg/kg extinguished the reverse effect of muscimol and GABA, respectively. In contrast, the GABAB antagonist CGP 35348 (3-aminopropane-diethoxymethyl-phosphinic acid) up to 100 mg/kg, i.p. failed to abolish the GABA effect; and baclofen, a GABAB-receptor agonist, at 0.5 and 2 mg/kg, i.p., 30 min before morphine was without effect on the delay. On the other hand, bicuculline was incapable of abolishing the reverse effects of diazepam on the delay of tolerance development; and likewise, the reverse effect of muscimol was not affected by flumazenil. No appreciable influence of these GABA-related compounds was seen on morphine antinociception itself nor the development of tolerance in normal mice. These results suggest that the benzodiazepine-GABAA-Cl- channel complex is involved in the mechanism underlying the delay of the development of morphine tolerance in formalin-treated mice; however, it is deduced that benzodiazepine-receptor and GABAergic systems are not always functionally coupled to each other in the mechanisms.

Analgesics, Opioid↗
PubMed1994

Pharmacokinetics of phenytoin in routine clinic patients in Malaysia.

We estimated individual and population Michaelis-Menten pharmacokinetic parameters for phenytoin (DPH) in epileptic patients attending our neurology clinic using the computer programme. OPT. Our results agreed well with literature values but were lower than those we obtained earlier in a smaller number of patients. The Km was independent of age, weight and sex but there was a weak, correlation between Vm and body weight. We conclude that the use of population Vm and Km in normograms could lead to errors in DPH dose estimations as they correlated very poorly with patient characteristics. OPT was easy to use and sufficiently accurate for deriving dose estimates in routine patients. Its use would enable practitioners to generate their patients' own parameters for use in individual dosage adjustments. The estimates can subsequently be updated as more data become available.

Adolescent↗
PubMed1994

Involvement of pain associated anxiety in the development of morphine tolerance in formalin treated mice.

The mechanism underlying the previous findings that the development of antinociceptive tolerance to morphine was significantly delayed in the presence of inflammatory pain induced by formalin was examined. Measurements of the pain threshold at different time intervals have shown that pain lasts around one week in the formalin treated mice. A single dose of indomethacin (10 mg/kg) or aspirin (400 mg/kg), 30 min before formalin injection, and daily 400 mg/kg of aspirin had no effects on the pain threshold or swelling, and it also did not affect the delay of morphine tolerance development. Daily administration of diazepam, 1 mg/kg, 1 hr before morphine injection completely abolished the delay. This effect was antagonized by 2 mg/kg of flumazenil, administered 15 min before diazepam injection. These results suggest that pain-associated anxiety participates in the delay of morphine tolerance development and consequently the benzodiazepine-receptor complex plays a role in the development of morphine tolerance during a painful state.

Animals↗
PubMed1994

Morphine dependence with or without tolerance in formalin-treated mice: further evidence for the dissociation.

Pain associated-anxiety induced by formalin, which resulted in a significant delay in the development of tolerance to morphine antinociception, failed to prevent the development of physical dependence as evidenced by naloxone challenge. Dependence also developed in mice rendered tolerant to morphine. Thus, the development of morphine dependence was observed in the absence and presence of tolerance to morphine antinociception; Our results further confirm the dissociation of opioid tolerance and dependence in the animal model of experimental pain/anxiety.

Analgesia↗
PubMed1993

Estimation of population pharmacokinetics for carbamazepine in Malaysian patients using the OPT computer program.

We used OPT to estimate individual and population pharmacokinetics for carbamazepine (CBZ) in Malaysian epileptic patients attending our Neurology Clinic. We noted that plasma CBZ concentrations and clearances correlated poorly with daily doses and body weights respectively but we found the values for clearance, volumes of distribution, elimination rate constants and half lives to be in good agreement with earlier reports. We conclude that OPT is a simple yet useful program to derive individual and population pharmacokinetic parameters for CBZ for use in dosage adjustments. We also conclude that although the Malaysian population do not differ substantially in handling CBZ, available data for the pharmacokinetic parameters must be used cautiously in applying it to the therapeutic drug monitoring for CBZ in our patients.

Adolescent↗
PubMed1993

Development of tolerance to morphine antinociception in mice treated with nociceptive stimulants.

We have examined whether or not the presence of pain can block the development of tolerance to morphine antinociception in mice. A single injection of formalin or Freund complete adjuvant into the dorsal part of one side of the hind paw resulted in a significant swelling of the treated paw which lasted more than 5 days. In formalin-treated animals that received the initial morphine 2 hr after the stimulant, the development of tolerance to morphine was delayed without affecting morphine antinociception when the effect was measured daily by the tail-pinch (TP) method but not by the tail-flick (TF) method. However, the stimulant suppressed tolerance development even in the TF method unless the daily measurement was undertaken. When morphine injection was started from 5 days after the formalin injection, tolerance developed in a pattern similar to that in the control animals. On the other hand, treatment with Freund adjuvant did not affect the development of tolerance measured by both the TP and TF methods, with or without daily measurement of antinociception. When acetic acid was used as a stimulant, daily morphine was administered before or after the acetic acid injection, in the presence or absence of pain, tolerance developed to the same extent as in the control group, regardless of the time of morphine injection. Thus, our results suggest that the development of tolerance to narcotics may be modified by various factors, such as the type and intensity of nociception; and they also suggest that different results may be produced depending on the test method.

Acetates↗
PubMed1990

Michaelis-Menten pharmacokinetics of phenytoin in adult Malaysian patients.

We reviewed our data from 122 records of patients taking phenytoin for the treatment of various types of epilepsy and selected 15 (age range 10-43 years old) who were on phenytoin alone to calculate Michaelis-Menten pharmacokinetic parameters. The average Vm and Km for this age group was found to be 8.45 mg/kg/day and 6.72 mg/litre, respectively. Km was independent of age and weight. Vm correlated well with weight but there was no relationship with age.

Adolescent↗
PubMed1989

Chronic colitis after Aeromonas infection.

Three patients with an acute colitis in which the only pathogen detected was either Aeromonas hydrophila or A sobria progressed to a chronic phase after the infection had been eliminated by antibiotic treatment in two and had resolved spontaneously in the third. The final diagnosis in each case was ulcerative colitis. Two of the patients have responded to anti-inflammatory medication but one has required panproctocolectomy. The sequence of symptoms and observations in these cases, as well as in others from the literature involving more familiar pathogens, suggests that bacterial infection may contribute to the development of chronic colitis. This supposition could be tested by extending the follow up of patients with acute infective colitis in a prospective multicentre trial.

Adult↗
PubMed1984

Monoclonal antibody against a cryptic carbohydrate antigen of murine and human lymphocytes. I. Antigen expression in non-cryptic or unsubstituted form on certain murine lymphomas, on a spontaneous murine mammary carcinoma, and on several human adenocarcinomas.

This paper describes an IgM monoclonal antibody (49H.8) which was produced following immunization of BALB/c mice with human neuraminidase-treated erythrocytes (NE-RBC). 49H.8 reacts with NE-RBC, neuraminidase-treated T lymphocytes (NE-T) and NE B lymphocytes of both human and murine origin. Little or no reactivity with untreated T or B cells could be detected. Thus the 49H.8 antigen is "cryptic" in most normal lymphocytes of both humans and mice. In contrast, the 49H.8 antigen was detected in non-cryptic or unsubstituted form on many non-treated murine lymphomas of both B- and T-cell origin, on the spontaneous murine mammary carcinoma, TA3-HA and on several human adenocarcinomas. The 49H.8 antigen appears to be related to the previously described 49H.24 antigen as shown by sugar inhibition experiments. 49H.24 reacts most strongly with the synthetic disaccharide (betaGa1 (I leads to 3)alpha Ga1NAc) but not at all with beta Ga1(I leads to 3)beta Ga1Nac. 49H.24 does not react with any of the murine or human tumors tested. 49H.8 reacts with both the alpha and beta forms of the disaccharide but reacts most strongly with phenyl-beta-galactoside-containing compounds. In contrast, phenyl-alpha-galactoside-containing compounds produced no reaction. The natural determinant detected by this antibody was not determined but various possibilities are considered. 49H.8 was used to detect antigen apparently shed from growing TA3-Ha cells into the serum and ascites of tumor-bearing mice. These observations suggest that the 49H.8 monoclonal antibody will be valuable as a specific reagent for a common tumor-associated antigen shared by certain murine and human tumors, and as a means of assaying shed tumor antigen in circulation as in the TA3-Ha mammary adenocarcinoma model.

Adenocarcinoma↗
PubMed1982

Hybridomas specific for carbohydrates; synthetic human blood group antigens for the production, selection, and characterization of monoclonal typing reagents.

A general method for the production of carbohydrate-specific hybridoma antibodies is illustrated by generation of monoclonal antibody to the antigenic determinant of human blood group B. This trisaccharide determinant was chemically synthesized and covalently coupled to bovine serum albumin and human blood group O red cells. Soluble protein antigen and the 'artificial' B red cells were used to immunize BALB/c mice before fusion of spleen cells with the Sp2/0 plasmacytoma cell line. ELISA screening of putative hybrids for B-specific binding activity was facilitated by the availability of a second synthetic conjugate, B-horse hemoglobin. IgM-producing clones were identified by class-specific ELISA reagents and by hemagglutination assay. In this way, clones suitable for blood typing were rapidly identified. The precise antigenic specificity and Ig class of such monoclonal antibodies were defined by inhibition of precipitation and by gel filtration. Hybridoma antibodies were obtained from two separate fusion experiments. One of these, clone 3E-4, was of the IgM class and possessed a binding site that was completely satisfied (100% inhibition) by the trisaccharide determinant of the B blood group. This antibody is shown to be suitable for use in blood typing.

ABO Blood-Group System↗
PubMed1982

A monoclonal antibody specific for the Thomsen-Friedenreich cryptic T antigen.

A monoclonal antibody (49H.24) is described that was made after immunization of BALB/c mice with human neuraminidase-treated erythrocytes (NE-RBC). 49H.24 is an IgM and reacts with NE-RBC but not untreated, normal human RBC. As little as 100 pg of antibody protein produced detectable direct agglutination of, or binding to, NE-RBC. The fine specificity of 49H.24 was determined by using a series of synthetic sugar haptens as inhibitors of agglutination or binding of 49H.24 to NE-RBC. Only synthetic T hapten (beta Gal(1 leads to 3)alpha GalNAc) produced complete inhibition of agglutination or binding, and no inhibition was produced by several other closely related haptens. Synthetic T hapten-coated silica beads (Synsorb) were used to affinity purify 49H.24. Affinity-purified antibody was radiolabeled with 125I and used in a sensitive competition assay to detect natural T antigen associated with cell membranes or in soluble form. The potential use of this or similar monoclonal antibodies as probes for an important human tumor marker is discussed.

Animals↗