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Biomedical subjects

E E Essien

Publications and source records attributed to E E Essien.

At least 19 recordsLinked to original sources
PubMed2001

Asymptomatic malaria parasitaemia in pregnant women at booking in a primary health care facility in a periurban community in Lagos, Nigeria.

Malaria can cause severe disease in pregnancy. We determined asymptomatic parasitaemia in 477 consenting consecutive women during their booking visits to a primary health care facility in a peri-urban area in Lagos State. There were 129 primigravidae and 348 multigravidae, with mean ages of 19.8 +/- 2.4 years (range 16-26 years) and 25.7 +/- 3.7 years (range 19-41 years), respectively. Most of the patients, 77.5% of primigravidae and 73.6% of multigravidae booked in the second trimester. Many (79.1%) of the primigravidae and 81.9% of the multigravidae had not taken any form of antimalaria chemoprophylaxis at the time of booking. Parasitaemia was significantly higher in the primigravidae than in the multigravidae 44.2% vs 33.6% (chi2 = 3.89, P < 0.05). In both primigravidae and multigravidae parasitaemia was highest in the second trimester compared with the two other trimesters (chi2 = 7.92, P < 0.02 and chi2 = 8.54, P < 0.01, respectively). There was no significant difference in parasitaemia among those who had anti-malaria chemoprophylaxis prior to booking and those who did not (P > 0.05). Prevalence of anaemia (PCV < 33%) was high, 73.6% in primigravidae and 69.8% in multigravidae, severe anaemia (PCV < 21%) however, was significantly associated with parasitaemia in the primigravidae (chi2 = 115, P < 0.001). Asymptomatic malaria parasitaemia at booking is high, hence we recommend parasites clearance in all patients at booking.

Adolescent↗
PubMed1991

Effect of repeated semen ejaculation on sperm quality.

The semen quality of 21 Medical students who produced sperm by masturbation has been assessed. The mean density of 21 samples examined on the first day was 64,4 millions per millilitre, while that on the third and fifth day of the study period were 52.2 and 50.7 millilitre respectively. This showed a statistically significant difference between the first and the third samples. Another statistically significant difference (P less than 0.5) was demonstrated in the semen volume of the first and third, and the third and fifth samples respectively. Significant differences were, however, not observed in the motility and morphology changes in the group samples. We therefore conclude that even though repeated semen ejaculations on alternate days do affect the density and volume of the semen, the most important overall effect is not such as to impair the potential fertility of the man who has normal initial sperm characteristics.

Adult↗
PubMed1990

N-oxidation: a possible route of tinidazole metabolism in man.

Treatment of tinidazole with a mixture of hydrogen peroxide and acetic acid, or liver homogenate preparations, yields the N-3 oxide. This was identified by thin-layer chromatographic analysis on silica gel G, Rf 0.6, using ethanol-chloroform-ammonia (50:49:1) as solvent, and by chemical reduction with sulphur dioxide. UV spectrophotometry and high performance liquid chromatography (HPLC) gave an RT of 0.55 min using Pye Unicam apparatus equipped with a UV detector at 330 nm, a reversed-phase RP 18 (10 microns) column which was 12.5 cm long, a mobile phase of methanol-0.005 M KH2PO4 (pH 4) (20:80, v/v) and a flow rate of 2 ml/min. In-vitro metabolic N-oxidation was achieved by incubating the parent drug, tinidazole, with rat liver homogenates fortified with cofactors at 37 degrees C. HPLC analysis of blood and urine samples from healthy volunteer subjects who took a single oral dose of tinidazole showed the presence of an in-vivo N-oxidation metabolite of the drug. The identical physico-chemical characteristics of the synthetic and biologically produced tinidazole N-oxide strongly suggest that tinidazole, a tertiary amine drug, undergoes metabolic N-oxidation.

Adult↗
PubMed1989

Determination of saliva: total plasma chloroquine levels relationship by high performance liquid chromatography.

The use of saliva chloroquine concentrations measurement as a noninvasive technique in the evaluation of the pharmacokinetics of the drug was investigated. Chloroquine concentrations in saliva and plasma were measured in eight healthy volunteers after a single oral dose of two tablets of chloroquine sulfate. The saliva: total plasma concentrations (S/P) ratio was found to be approximately constant in the absorption (0.4 +/- 0.07), distribution (0.47 +/- 0.08), and elimination (0.46 +/- 0.05) phases. Thus, saliva sampling for chloroquine concentrations was found to be a useful noninvasive technique for the estimation of all the pharmacokinetic parameters of the drug and hence, for chloroquine pharmacokinetic studies.

Adult↗
PubMed1989

Pharmacokinetics of chloroquine and some of its metabolites in healthy volunteers: a single dose study.

Eight healthy volunteers who had not taken chloroquine 2 to 12 months previously participated in a single dose study designed to evaluate the pharmacokinetics of chloroquine and some of its metabolites. Each subject received two tablets of chloroquine sulfate (300 mg base) only. Blood and urine samples were collected just before and periodically after chloroquine administration. These samples were assayed for chloroquine and its N-dealkylated metabolites (monodesethylchloroquine, didesethylchloroquine, 7-chloro-4-aminoquinoline), chloroquine side chain N-oxide and chloroquine di-N-oxide using a high performance liquid chromatographic method. Residual levels of chloroquine and its N-oxidation metabolites were found in all subjects. 7-chloro-4-aminoquinoline was eliminated more slowly (t1/2z = 126.48 +/- 20.13 h) than the other metabolites and the unchanged drug (t1/2z = 106.43 +/- 10.13 h). Also, 7-chloro-4-aminoquinoline had a significantly faster (Student's t-test, P less than 0.05) formation clearance when compared with the other metabolites. The plasma concentration of 7-chloro-4-aminoquinoline was about twice that of the unchanged drug while the plasma concentration of monodesethylchloroquine was about 46% that of the unchanged drug. In order to investigate whether the metabolites were produced from the same binding sites or closely related sites on the cytochrome P-450 system, their formation clearances were correlated. The best correlation (r2 = 0.83) was observed for didesethylchloroquine and monodesethylchloroquine, and a fair correlation (r2 = 0.59) was observed for monodesethylchloroquine and 7-chloro-4-aminoquinoline. Formation clearances of the other metabolites were poorly correlated.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1989

Asymptomatic bacteriuria in pregnant Nigerian patients.

One-thousand out of a total obstetric population of 3,548 patients seen between January and December, 1985, were screened for asymptomatic bacteriuria. During the first trimester, the observed incidence was 5.3 per cent while in the second and third trimesters it was 4.1 and 2.8 per cent, respectively. The overall pick-up rate was 4.0 per cent. The significance of this observation was discussed. Escherichia coli was the predominant causative micro-organism, accounting for 45 per cent of cases. A seven-day sensitive antibiotic therapy eradicated all the positive cases. The qualitative culture method as described in this study is a simple, sensitive and reliable method of screening for bacteriuria in pregnancy, especially as it can be used for identification of the causative organism and its antibiotic sensitivity.

Bacteriuria↗
PubMed1988

Passage of chloroquine into semen.

The passage of chloroquine into semen was investigated in four healthy men following the oral administration of four chloroquine sulphate tablets (600 mg base) to each subject. Chloroquine was found to be excreted into semen with a slow transfer rate constant of 0.0002 min-1, and the semen/plasma ratio based on regression analysis was 0.40 +/- 0.06 (mean +/- s.d.). It is concluded that the passage of chloroquine from plasma to semen occurs by passive diffusion.

Adult↗
PubMed1988

Chloroquine-induced acute dystonic reactions in the presence of metronidazole.

A 30-year-old woman underwent laparotomy and was placed on a seven-day course of metronidazole and ampicillin postoperatively. Chloroquine therapy for malaria was instituted on the sixth day and the patient developed acute dystonic reactions after a single dose. Diphenhydramine therapy before chloroquine administration did not prevent the development of the dystonic reactions. The extrapyramidal symptoms subsided upon diazepam administration and chloroquine withdrawal even though metronidazole therapy was continued. The mechanism of this adverse drug reaction based on the pharmacodynamic interaction between chloroquine and metronidazole is discussed. It is suggested that the combination of pyrimethamine and sulfadoxine be used in place of chloroquine for malaria chemotherapy in patients on metronidazole therapy.

Adult↗
PubMed1987

Chloroquine elimination in humans: effect of low-dose cimetidine.

A controlled study was carried out in ten healthy, male volunteers (randomly distributed into control and test groups of five subjects each) to determine the effect of low-dose cimetidine on chloroquine elimination. The control group subjects received two tablets of chloroquine sulfate (300-mg base) only, while the test group subjects took 400-mg cimetidine at bedtime for four days prior to chloroquine (two tablets of chloroquine sulfate) administration and throughout the duration of the study. Blood samples, 5 mL, were collected periodically after chloroquine administration. The samples were assayed for chloroquine and monodesethylchloroquine using a combination of thin-layer chromatography and spectrophotometry. Wilcoxon's test for unpaired data at P less than .05 was used to determine if there was any significant difference in the elimination of chloroquine in the test group when compared with the control group. The apparent oral clearance rate of chloroquine was reduced from 0.49 +/- 0.04 L/d/kg in the control group to 0.23 +/- 0.02 L/d/kg in the test group, and the elimination half-life was prolonged from 3.11 days in the control group to 4.62 days in the test group. There was a 47.04% reduction in the AUC0-7d of monodesethylchloroquine, the major metabolite of chloroquine, in the test group when compared with the control group. The apparent volume of distribution at steady state was increased from 0.46 +/- 0.07 L/kg in the control group to 0.72 +/- 0.10 L/kg in the test group. All these changes were statistically significant. The conclusion is that cimetidine impairs the elimination of chloroquine in healthy subjects.

Adult↗
PubMed1987

Chloroquine in human milk.

Simultaneous milk and saliva samples were collected over a seven-day period from five lactating subjects after they had ingested two tablets of chloroquine sulfate (300 mg base). The samples were analyzed for chloroquine content by use of a combination of thin-layer chromatography and spectrophotometry. Regression analysis of two variables subject to error was used to determine the milk:saliva levels relationship. The Student's t test for paired data at .05 level of significance was used to evaluate the relationship between chloroquine levels in milk and saliva. The milk:saliva chloroquine concentrations ratio obtained by regression analysis was 0.89 +/- 0.08 (r = .93; P less than .05), and this compared favorably with the value of 0.99 +/- 0.07 obtained from the ratio of the AUC. There were no significant differences in the Tmax, Cmax, AUC, clearance, and elimination half-life values of chloroquine in milk and saliva (P greater than .05). Milk and saliva appear to be part of the central compartment. The amount of chloroquine estimated to be consumed by a nursling over a 24-hour period is about 0.55% of a 300-mg dose consumed by the mother. The data suggest that milk chloroquine levels can be estimated from saliva levels.

Adult↗
PubMed1987

Metabolic N-oxidation of metronidazole.

Metronidazole when treated at the N-3 nitrogen with a mixture of hydrogen peroxide and acetic acid, or liver homogenate preparations, yields the N-3 oxide as identified by thin-layer chromatographic analysis on silica gel G, RF 0.62 in ethanol-chloroform-ammonia (50:49:1), by chemical reduction with sulphur dioxide, and by ultra-violet spectrophotometry and nuclear magnetic resonance spectroscopy. Incubation of metronidazole at 37 degrees C with rat liver 10,000g supernatant fortified with cofactors gave a product with identical chromatographic and UV spectral data suggesting that metronidazole like other tertiary amine drugs undergoes microsomal N-oxidation.

Animals↗
PubMed1987

Effect of ranitidine on chloroquine disposition.

Ten healthy, male volunteers (aged 19-27 yr; weight 62-67 kg) were randomly distributed into control and test groups of five subjects each in a controlled study on the effect of ranitidine on chloroquine disposition. The control group subjects received two tablets of chloroquine sulfate (300-mg base) only. The test group subjects received ranitidine 250 mg hs for four days prior to the administration of chloroquine sulfate and throughout the sample collection period. Blood samples (5 ml) were collected from the time of the chloroquine administration to the seventh day after drug administration. The samples were analyzed for chloroquine content by a combination of thin-layer chromatography and ultraviolet spectrophotometry. The Wilcoxon test at 0.05 significance level was used to compare the disposition parameters between control and test groups. Ranitidine therapy was associated with no significant alterations in chloroquine oral clearance rate, elimination rate constant, and apparent volume of distribution. Unlike cimetidine, ranitidine does not interact pharmacokinetically with chloroquine. Ranitidine, therefore, may be the H2-receptor antagonist of choice for ulcer patients receiving chloroquine.

Adult↗
PubMed1986

Effects of chloroquine and didesethylchloroquine on rabbit myocardium and mitochondria.

The effects of chloroquine and didesethylchloroquine on the rabbit isolated perfused heart and on calcium binding and accumulating ability of the heart mitochondria were investigated. The drugs produced negative chronotropy, negative inotropy and a decrease in coronary flow rate in the isolated perfused myocardium. Both chloroquine and didesethylchloroquine significantly decreased mitochondrial calcium binding and accumulation. These results suggest that the cardiodepressant actions of chloroquine could be due in part to alterations in the calcium accumulating abilities of the mitochondrial membranes, and that didesethylchloroquine, among other metabolites, does contribute significantly to the total observed effect of chloroquine on the cardiovascular system.

Animals↗
PubMed1985

Metronidazole-induced myocardial depression: chemical and pharmacological studies on the role of calcium in-vitro.

The interaction of metronidazole with calcium to form a water-soluble complex has been studied by titration with ethylenediaminetetraacetate (EDTA), direct current and pulse polarographic reduction steps of the nitro-group at pH 5 and 7, and by ultraviolet absorption. Stoichiometric calculations, X-ray powder diffraction pattern of the synthesized metronidazole-calcium complex, and molecular ion peak at m/z 381 in the mass spectrum of this product, showed that a 2:1 complex is formed. The interaction of metronidazole with calcium on myocardial contractile performance of guinea-pig electrically-driven isolated left atria in physiological solution was also examined. Metronidazole induced a sustained, concentration-dependent depression of the tension that was reversed by changing the bathing fluid to physiological solution, and/or by adding excess calcium ion. The drug-induced negative inotropic response was antagonized competitively by increasing calcium ion in the bath, whereas noradrenaline antagonized metronidazole-induced negative inotropic responses non-competitively. Addition of the metronidazole-calcium complex to the bath did not affect normal myocardial contractile performance. The results show that metronidazole produces a direct negative inotropic effect on isolated atrial muscles by interfering with Ca2+, and by preventing Ca2+ function in the events leading to contractile activity of atrial muscles.

Animals↗
PubMed1984

Residual chloroquine and metabolites in man as a sequel of previous chloroquine medications: a urinary excretion study and its significance.

In malaria-endemic areas like Nigeria, chloroquine is used frequently and extensively in the management of attacks. In this investigation urine samples of six different adult subjects showed a significantly wide range of excretion of total chloroquine and metabolites (10.01 to 0.021 mg) in 12 h due to residual levels of the drug in the subjects as a function of time of last medication with the drug. Two subjects representing extreme users of the drug--a naive subject and a frequent user--were given 300 mg of chloroquine each and the excretion rate profile monitored for 24 h. The first-time user of chloroquine showed a typical cumulative excretion pattern with total excretion of 16 mg while the frequent user showed a bimodal cumulative excretion curve with the second phase tending to a higher plateau effect and a total excretion of 21 mg in 24 h. These different levels of total excretion could be attributed to the influence of protein binding and tissue accumulation of the drug in the frequent user, and a second-phase excretion related to release of some bound chloroquine and metabolites. These effects are considered in relation to accumulation of chloroquine in the body resulting from frequent medication with the drug. Information regarding the time of last medication, and residual levels of chloroquine and metabolites is necessary for instituting the appropriate therapeutic regimen. The assay techniques involving single selective solvent extraction, thin-layer chromatography and spectrophotometric measurements, have been found adequately quantitative, simple and quick for use in routine clinical laboratory investigation.

Adult↗
PubMed1983

Complete heart block in chronic chloroquine poisoning.

Complete heart block of recent onset is reported and is attributed to chronic chloroquine abuse. Total blood chloroquine was more than two times higher in this patient than in 4 patients following therapeutic doses of chloroquine, and chloroquine basic metabolites were also proportionally higher in this patient's blood.

Chloroquine↗
PubMed1982

Chloroquine and its metabolites in human cord blood, neonatal blood, and urine after maternal medication.

Chloroquine, its N-dealkylated metabolites, and chloroquine N-oxides were detected in the urine of pregnant women who were receiving chloroquine medication whereas chloroquine and its nonpolar metabolites, desethyl- and didesethylchloroquine and 7-chloro-4-aminoquinoline, have been found in the neonates' urine, blood, and cord blood. We used thin-layer chromatography to separate chloroquine and its metabolites after their extraction from biological fluids. These compounds were identified by comparing their chromatographic and ultraviolet spectrophotometric characteristics with those of reference compounds. That chloroquine and its relatively nonpolar metabolites (including one without the alkyl side-chain, 7-chloro-4-aminoquinoline) cross the placenta is demonstrated by the presence of these compounds in the cord blood, neonatal systemic blood, and neonatal urine. The selective transfer of the compounds in the cord blood, neonatal system blood, and neonatal urine. The selective transfer of the compounds across the placenta and the clinical implications of these findings are discussed.

Chloroquine↗