Undergraduate Students' Knowledge and Practice of Gonorrhea and other Sexually Transmitted Infections.

BACKGROUND: Sexually transmitted infections (STIs) are a major public health issue. Adolescents and youth (15-24 years) are the age groups at the greater risk for acquiring them. Also a large percentage of new STIs occur in this age group with 7000 young people worldwide acquiring the infection every day. Sexually transmitted infections (STIs) are poorly recognized and inadequately treated in Nigeria despite the fact that they constitute a major risk factor for sexual transmission of HIV infection. The shortage of trained human resources is among the most important obstacles to strengthening health systems in low-income countries. OBJECTIVE: This study is to document the knowledge and practice of undergraduate students about gonorrhoea and other STIs as a baseline survey for future intervention work. METHODS: It was a questionnaire-based, cross sectional descriptive study of the knowledge and practice of STIs among students in the seven public tertiary academic institutions in Lagos State using list obtained from the Lagos State Ministry of Education. Thirty (30) students who agreed to be surveyed were conveniently selected from each school. Pre-tested, semi-structured, validated questionnaires were administered and collected back. Data was entered into Microsoft Excel and analysed using EPI Info, SPSS version 15 and Microsoft Excel. Results were considered to be statistically significant if p < 0.05. RESULTS: Majority of the respondents were of the 21 - 25 year age range (48%) and were mainly single (95%), Christian (61%) and Yoruba (81%). About 51% of the respondents had at least good knowledge of gonorrhoea and other STIs. Knowledge about symptoms and transmission was higher than knowledge of prevention, consequences and drugs. Among those that are sexually active 24% do not use condom while 10% reuse condom. Use of both modern and traditional medical practitioners (TMP) was documented among the students. CONCLUSIONS: Awareness programs with key messages about gonorrhoea and other STIs should be developed and circulated widely in tertiary institutions in the state to improve students' practice. Also strategies to embrace TMP for STI management should be evolved.

Pattern and determinants of antiretroviral drug adherence among Nigerian pregnant women.

BACKGROUND: The need for a high level of adherence to antiretroviral drugs has remained a major hurdle to achieving maximal benefit from its use in pregnancy. This study was designed to determine the level of adherence and identify factors that influence adherence during pregnancy. METHOD: This is a cross-sectional study utilizing a semistructured questionnaire. Bivariate and multiple logistic regression models were used to determine factors independently associated with good drug adherence during pregnancy. RESULT: 137 (80.6%) of the interviewed 170 women achieved adherence level of ≥ 95% using 3 day recall. The desire to protect the unborn child was the greatest motivation (51.8%) for good adherence. Fear of being identified as HIV positive (63.6%) was the most common reason for nonadherence. Marital status, disclosure of HIV status, good knowledge of ART, and having a treatment supporter were found to be significantly associated with good adherence at bivariate analysis. However, after controlling for confounders, only HIV status disclosure and having a treatment partner retained their association with good adherence. CONCLUSION: Disclosure of HIV status and having treatment support are associated with good adherence. Maternal desire to protect the child was the greatest motivator for adherence.

Antimalarial prescribing patterns in state hospitals and selected parastatal hospitals in Lagos, Nigeria.

BACKGROUND: Malaria is a curable and preventable disease and it is a major public health problem in Nigeria. Chloroquine was the first line drug in its treatment in Nigeria until recently where the Artemisinin based Combination Therapies (ACTs) are being promoted. Inappropriate prescribing, i.e., the failure to prescribe drugs in accordance with guidelines based on scientific evidence to ensure safe, effective, and economic use, is an irrational drug use behavior. Increased benefits from chloroquine or a slowdown of progression to resistance could be achieved by improving prescribing practice, drug quality, and patient compliance. OBJECTIVE: To determine the antimalarial prescribing pattern and to assess rational prescribing of chloroquine by prescribers in government hospitals and parastatals in Lagos State. METHODS: The study was carried out in all the ten government General Hospitals under Lagos State Hospitals Management Board (now Lagos State Health Service Commission), one parastatal hospital and one oil company clinic, using patient prescriptions. One hundred prescriptions each for adults and children for each month for a period of one year (January to December 2000) were systematically sampled. Where there were fewer than 100 prescriptions in a month, all the prescriptions available were sampled for analysis. RESULTS: Average number of drugs per encounter in all the hospitals was 4.259 +/- 0.009. Average number of injections per encounter was 1.215 +/- 0.009. About 48.5% of all the presriptions had at least one injection while 40.9% of the prescriptions had dipyrone injection. Average drug cost per encounter was N 147.40 +/- 0.765. Percentage of encounters with chloroquine was 82.5% followed by sulphadoxine-pyrimethamine 14.2%. Percentage of prescriptions with correct dose of chloroquine was 47.5% CONCLUSIONS: Polypharmacy exists in all the hospitals. The average number of drugs per encounter for the majority of the hospitals was above 4. Less than half of the prescriptions had the correct dose of chloroquine. This study can serve as a baseline for intervention on irrational prescribing.

Antimalarial Prescribing Patterns in State Hospitals and Selected Parastatal Hospitals in Lagos; Nigeria

Background: Malaria is a curable and preventable disease and it is a major public health problem in Nigeria. Chloroquine was the first line drug in its treatment in Nigeria until recently where the Artemisinin based Combination Therapies (ACTs) are being promoted. Inappropriate prescribing i.e. the failure to prescribe drugs in accordance with guidelines based on scientific evidence to ensure safe; effective; and economic use; is an irrational drug use behavior. Increased benefits from chloroquine or a slowdown of progression to resistance could be achieved by improving prescribing practice; drug quality; and patient compliance. Objective: To determine the antimalarial prescribing pattern and to assess rational prescribing of chloroquine by prescribers in government hospitals and parastatals in Lagos State. Methods: The study was carried out in all the ten government General Hospitals under Lagos State Hospitals Management Board (now Lagos State Health Service Commission); one parastatal hospital and one oil company clinic; using patient prescriptions. One hundred prescriptions each for adults and children for each month for a period of one year ( January to December 2000) were systematically sampled. Where there were fewer than 100 prescriptions in a month; all the prescriptions available were sampled for analysis. Results: Average number of drugs per encounter in all the hospitals was 4.259 + 0.009. Average number of injections per encounter was 1.215 + 0.009. About 48.5of all the presriptions had at least one injection while 40.9of the prescriptions had dipyrone injection. Average drug cost per encounter was N 147.40 + 0.765. Percentage of encounters with chloroquine was 82.5followed by sulphadoxinepyrimethamine 14.2. Percentage of prescriptions with correct dose of chloroquine was 47.5Conclusions: Polypharmacy exists in all the hospitals.The average number of drugs per encounter for the majority of the hospitals was above 4 . Less than half of the prescriptions had the correct dose of chloroquine. This study can serve as a baseline for intervention on irrational prescribing

Drug supply strategies, constraints and prospects in Nigeria.

The study set out to identify the strategies for public drug supply in Nigeria, assess its functionality, and recommend appropriate means to ensure regular availability of safe, efficacious, good quality and affordable essential drugs at public health facilities. The investigation was carried out at the Directorate of Pharmaceutical services, Federal Ministry of Health (F.M.O.H) Abuja and Federal Medical Stores, Oshodi, Lagos. Semi-structured interview was conducted with key informants at the Department of Food & Drugs, Drug procurement unit and Central Medical store using structured questionnaires and direct informants answers. Our study shows that public drug supply in Nigeria is governed by a National Drug Policy (NDP) which was introduced in 1990 and it is yet to be reviewed after ten years. We also identified the Central Medical Store (CMS) system as the current public drug supply strategy in Nigeria. Public drug supply is mainly financed by governments and this is inadequate to ensure sustained availability of essential drugs. The major procurement methods in use are open tender and direct procurement. These methods as presently operated suffer from late order placement, delay in payment and poor supplier lead-time mainly attributable to lateness in payment for previous drug supplies. These have contributed to stock out of essential drugs at public health facilities. Major losses due to expiration and spoilage are recorded at both central and peripheral storage points despite adequacy of storage facilities and personnel. Road transportation was the major mode of drug distribution from central to peripheral storage points and shortage of vehicle was a key factor affecting drug distribution. There was an apparent lack of a functioning drug management information system to effectively coordinate public drug supply and there are no definite systems that monitor and evaluate staff performance. The CMS strategy currently used for public drug supply in Nigeria has not ensured regular availability of essential drugs at public health facilities. Our study suggests that this is more of an administrative failure. Public drug supply in Nigeria is therefore in need of urgent reforms and this could be achieved through the use of an autonomous drug supply agency to assure efficiency and sustainability.

Bioequivalence of pyrantel pamoate dosage forms in healthy human subjects.

Drugs that are largely restricted to the gastro-intestinal tract (GIT) for their therapeutic efficacy and that are not substantially absorbed into the body are usually inadequately studied in terms of systemic bioavailability. The possibility of systemic effects requires that bioavailabilities be studied to ensure against enhanced toxicity resulting from formulation differences. Pyrantel pamoate falls into this category. High-performance liquid chromatography was employed in this study to determine plasma levels of pyrantel in nine healthy human subjects after administration of tablet and suspension dosage forms. Mean peak plasma concentrations of 37.56 +/- 9.37, 35.89 +/- 8.94, and 36.22 +/- 10.10 ng mL-1 were obtained following administration of 750 mg pyrantel pamoate in three different formulations. The mean tmax values were 2.02 +/- 0.12, 2.05 +/- 0.356, and 2.05 +/- 0.339 h respectively for the above dosage forms; the respective AUC0-9 values were 81.01 +/- 12.97, 94.59 +/- 17.18, and 101.47 +/- 19.59 h ng mL-1. There was no statistically significant difference between the bioavailabilities of the dosage forms tested. Large inter-subject variations were observed. One subject experienced abdominal discomfort and one experienced dizziness. It was not possible to clearly correlate individual variations in absorption with the observed adverse effect because the number of incidents was low (two out of 27 treatments).

Role of the endothelium and smooth muscle tone in the dilator response of the rabbit coeliac artery to histamine.

The role of the endothelium and vascular tone was studied on histamine-induced relaxation and contraction of the rabbit coeliac artery. Histamine contracted the tissue via the release of noradrenaline (NA), an action blocked by prazosin and mepyramine but not influenced by endothelial removal. Tachyphylaxis readily developed to histamine-induced contractions. After a moderate tone (40-55%) was induced with NA, histamine relaxed the tissues concentration-dependently. This relaxation was absent when the endothelium was removed indicating that the receptors involved are located on the endothelium. When the tone was increased to 80-85% with NA, relaxation could only be demonstrated after blocking H1-receptors. Removal of the endothelium did not influence this response. The relaxant effect of histamine in both preparations, however, was blocked by metiamide indicating that it is H2-receptor mediated. In the rabbit coeliac artery, endothelial H2-receptors are readily activated at moderate tone while muscular H2-receptors are stimulated at high tone after blocking H1-receptors. The predominance of H2-receptors in this artery may serve the physiological function of vasodilation in the blood vessels of the stomach.

Comparative effects of acetylcholine on the reptilian and mammalian aortae.

Responses of the lizard and the rabbit thoracic aortae to acetylcholine were studied. Acetylcholine (ACh) (10 nM-100 microM), carbachol (10 nM-50 microM) and PGF2 alpha (100 nM-100 microM) produced concentration-dependent contractions of the lizard thoracic aorta (LTA) with rapid tachyphylaxis. On the other hand, acetylcholine and carbachol relaxed the rabbit thoracic aorta (RTA) dose-dependently. There was no tachyphylaxis. Tachyphylaxis in the LTA was prevented by indomethacin (1 microM) or by rubbing the endothelium. Endothelial removal abolished ACh-induced relaxation of the RTA. Relaxation of the RTA and contractions of LTA were blocked by atropine, pirenzepine, acetoxy-N-methyl-piperidine methbromide (4-DAMP) and diltiazem. Removal of the endothelium rendered RTA insensitive to ACh. However, ACh-induced contractions of the LTA were not so influenced by removal of endothelial cells. It is concluded that the lizard thoracic aorta releases a metabolite of arachidonic acid that mediates tachyphylaxis. Relaxation of the RTA after ACh is mediated via the release of endothelium-dependent relaxing factor.

Extracellular calcium dependence of contraction and endothelium-dependent relaxation varies along the length of the aorta and its branches.

Dependence of contraction and endothelium-dependent relaxation of segments of the rabbit aorta and the celiac, superior mesenteric and renal arteries on the presence of calcium in the physiological salt solution in which they were bathed have been studied in vitro. Arteries were tested before and 60 min after removal of Ca++ from the bath solution. Norepinephrine-induced contraction and acetylcholine and A23187-induced relaxation were calcium-dependent in the thoracic and upper abdominal aorta. Contractions were resistant to the effect of calcium removal in segments from the aorta below the origin of the renal artery and from the renal artery itself. The aorta between the superior mesenteric and the renal arteries was intermediate in its dependence. Relaxation of the aorta caudal to the origin of the celiac artery and the renal artery was also resistant. The insertion of an intact everted vessel into an artery whose intima had been inactivated by rubbing restored partially the relaxation to acetylcholine and A23187 in the presence of normal calcium. Vessels that did not relax to acetylcholine after Ca++ exclusion from the bathing solution relaxed when the renal artery was the donor. Donor arteries whose relaxation was sensitive to Ca++ removal did not increase the relaxation response of the renal artery after calcium removal. Diltiazem and D600 reduced the relaxation responses of acetylcholine in the thoracic aorta and enhanced those in the renal artery. It is concluded that there is a transition in the extracellular Ca++ dependence of contraction and endothelium-derived relaxation along the length of the abdominal aorta. Changes in the dependence of contraction occurred more gradually than relaxation.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in postjunctional alpha-adrenoceptors during postnatal growth in rabbit arteries.

The pharmacological characteristics of the postjunctional alpha-adrenoceptors of vascular smooth muscle were studied in ring segments of thoracic aorta, superior mesenteric, and central ear arteries of 4- and 8-week-old, and young adult (12- to 16-week-old) rabbits. Norepinephrine (alpha 1, alpha 2-agonist), phenylephrine (alpha 1-agonist), and UK 14,304-18 (alpha 1-agonist) caused a concentration-dependent contraction of all three arterial segments from 4- and 8-week-old animals. Norepinephrine and phenylephrine but not UK 14,304-18 contracted the young adult thoracic aorta and superior mesenteric artery, whereas all the agonists contracted the central ear artery. The effects of the alpha 1-adrenoceptor antagonists, prazosin and thymoxamine, and the alpha 2-adrenoceptor antagonists, rauwolscine and yohimbine, on these responses were studied. In the 4-week-old rabbits, responses to norepinephrine, phenylephrine, and UK 14,304-18 were reduced by all four antagonists with nominal pA2 values in the range of 7-8.5. The action of the antagonists was competitive. Between 4 and 8 weeks, there was a significant decrease in the pA2 values of rauwolscine against norepinephrine and UK 14,304-18 in the aorta and between rauwolscine and UK 14,304-18 on the superior mesenteric artery. The pA2 values of rauwolscine and yohimbine, but not prazosin and thymoxamine, were lower in the young adult compared with values from the 8-week-old rabbit. In the interpretation of these results, there are two possibilities.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacological characterization of histamine receptors in the rabbit renal artery.

Histamine receptors were characterized pharmacologically in the rabbit renal artery. Histamine concentration-dependent contractions were blocked by chlorpheniramine (pA2 = 8.25 +/- 0.16) and mepyramine (pA2 = 9.80 +/- 0.22). A low concentration of metiamide (0.5 microM) enhanced significantly the effect of histamine. Higher concentrations either had no effect or reduced the contractile response to histamine. Impromidine, dimaprit and, in the presence of chlorpheniramine or mepyramine, histamine (at the concentrations that produced contractions) relaxed the precontracted vessel. The relaxant effect of histamine was quantitatively greater in the presence of mepyramine than it was in the presence of chlorpheniramine. Endothelial removal did not influence the contractile response to histamine but enhanced the relaxation suggesting the presence of histamine receptors mediating contraction in the intima. Relaxation responses to histamine and dimaprit were blocked competitively by cimetidine (pA2 = 6.65 +/- 0.10 and 6.60 +/- 0.05 respectively). It is concluded that there are two types of histamine receptors in the renal artery of the rabbit; H1-receptor mediating contraction and H2-receptor mediating relaxation. Both types of receptors are present in the media: some excitatory receptors may be present in the intima.

Pharmacological analysis of the postjunctional alpha-adrenoceptors of the rat anococcygeus muscle and vas deferens.

The alpha-adrenoceptor sub-type of the rat vas deferens was characterized with noradrenaline (alpha-1, alpha-2-agonist), phenylephrine (alpha-1-agonist), prazosin (alpha-1-antagonist) and yohimbine (alpha-2-antagonist) and compared with the results obtained in the rat anococcygeus muscle. In the vas deferens, both prazosin and phentolamine were competitive antagonists of noradrenaline and phenylephrine whereas yohimbine was a non-competitive antagonist irrespective of the concentrations of these antagonists. On the other hand, in the anococcygeus muscle, at low concentrations, prazosin was non-competitive against noradrenaline whilst it was competitive against phenylephrine. Yohimbine behaved as a competitive antagonist of noradrenaline at both low and high concentrations whilst at low concentrations it was non-competitive against phenylephrine. These results suggest a predominance of alpha-1-adrenoceptors in the vas deferens located postjunctionally with a small population of alpha-2-subtype adrenoceptors, whilst the anococcygeus muscle seems to contain relatively more alpha 2-adrenoceptors postjunctionally than the vas deferens.

Tricyclic antidepressants antagonize prostaglandin (PG) E2-induced contractions of the guinea pig ileum and hypomotility in the mouse.

The interactions of PGE2 and 2 tricyclic antidepressants were tested both on the guinea pig ileum and motility in the mouse. PGE2-induced contractions of the guinea pig ileum were irreversibly blocked by amitriptyline and desipramine. Chronic administration of amitriptyline and desipramine blocked PGE2-induced hypomotility in the mouse.

Interactions of 5-hydroxytryptamine and tricyclic antidepressants in the rat stomach strip and the guinea-pig ileum.

The interactions of the tricyclic antidepressants, amitriptyline and desipramine with 5-hydroxytryptamine (5-HT) were studied in the guinea-pig ileum and in the rat stomach strip. The tricyclics blocked the contractile response of the guinea-pig ileum and severely depressed the maximum [amitriptyline greater than desipramine (DMI)], however, they potentiated (DMI greater than amitriptyline) 5-HT-induced contractions of the RSS. The potentiation induced with DMI seems to be a combination of uptake inhibition and some post-receptor sensitization whilst amitriptyline-induced potentiation may be due to the former. Higher concentrations of the tricyclics contract the RSS. These contractions were absent in reserpinized RSS. Reserpinization reduced the potentiation after tricyclics and DMI was unable to enhance maximal concentrations of 5-HT, i.e. the post-receptor effect of DMI seems to have been abolished. It is concluded that whilst the tricyclics may be irreversible antagonists of 5-HT in the guinea-pig ileum, they potentiate the effect of 5-HT in the RSS by uptake inhibition, and, in the case of DMI, some additional post-receptor effect.

Effects of frusemide, ethacrynic acid and chlorothiazide on the portal vein of normotensive and spontaneously hypertensive rats.

The effects of frusemide, ethacrynic acid and chlorothiazide were studied in the Wistar Kyoto (WKY) rats and spontaneously hypertensive rat (SHR) portal veins in vitro. Frusemide produced concentration-dependent contractions of the portal vein from both WKY control and SHR. The WKY were more sensitive (as judged by the EC50) whilst a greater maximal response was generated in the SHR. The contractile response to frusemide in WKY rats was attenuated reversibly by phenoxybenzamine whereas the latter was ineffective in the SHR. Ethacrynic acid produced reductions of the myogenic rhythmic contractions of the portal vein in a concentration-related manner in both WKY and SHR. The inhibitory action of ethacrynic acid was greater in the SHR than in the WKY control rats. The inhibitory action of ethacrynic acid was blocked by propranolol suggesting the involvement of beta adrenoceptors. Chlorothiazide, on its own, had no observable effect on the portal vein. However, it reduced the sensitivity of the vein to noradrenaline and K+. This reduction was greater in the SHR than in the WKY. It is concluded that some of the observed effects of these diuretics may contribute beneficially to their anti-hypertensive actions.

Presynaptic alpha-receptor control of adrenergic transmitter release in blood vessels.

The presynaptic alpha-adrenergic receptor control of transmitter release in vascular tissues is discussed. A model of adrenergic innervation of the vascular bed is proposed based on ultrastructural and histochemical evidence. Evidence is presented to support the concept of intermittent or periodic release of norepinephrine (NE) from the varicosity. Intermittency combined with a mechanism such as presynaptic control to ensure spatial distribution of release sites, along with a slow effector response and recovery, results in a smooth, generalized change in tone and an overall economy of transmitter. The effective concentration of NE around the presynaptic membrane is maintained for considerably less than 0.1 s. It is argued that the transient presence of transmitter in the synapse combined with intermittency of release does not favor accumulation of transmitter at the cleft at physiological frequencies or desensitization of presynaptic receptors. In addition, intermittency provides an explanation for why exogenous NE is more effective presynaptically in influencing release than endogenous NE. The importance of cleft width in presynaptic control of transmitter release, the possible complications caused by facilitation, and resolution of some apparent problems with the presynaptic hypothesis are also discussed.

Are there alpha-adrenoceptors in the young chick atria?

The effect of noradrenaline and isoprenaline were studied in the 15-day old chick atria. Noradrenaline increased both the rate and force of atrial contractions whilst isoprenaline only slightly increased force at very high concentrations. The increase in force after noradrenaline and isoprenaline was reduced by phentolamine, an alpha-adrenoceptor antagonist. The beta-antagonist, propranolol and the cardioselective beta 1-adrenoceptor antagonist, atenolol, did not reduce the positive inotropy. Noradrenaline-induced positive chronotropy was, however, resistant to both alpha- and beta-adrenoceptor blockade. It is concluded that the force of contraction of the chick atria may be alpha-adrenoceptor-mediated whilst the rate seems to be mediated by a mechanism sensitive to noradrenaline but insensitive to alpha- and beta-adrenoceptor blockade.

Fasting reduces the responses of the rat vas deferens to sympathomimetics.

The effect of fasting, L-DOPA pretreatment and high glucose medium on the response of the rat vas deferens to sympathomimetics was studied in vitro. The contractile responses of the rat isolated vas deferens were reduced by fasting, the effect being significant after 24-hr fast with noradrenaline and tyramine, after a 48-hr fast with dopamine, and after a 72-hr fast with methoxamine. Treatment with L-DOPA for 7 days before sacrifice abolished the effect of a 24-hr fast in reducing responses to noradrenaline and tyramine, and the response to methoxamine after a 72-hr fast was enhanced. Doubling the concentration of glucose in the solution bathing the isolated vas deferens from rats fasted for 24 hr increased the responses to noradrenaline and tyramine. It is concluded that fasting reduces the responses of the rat vas deferens to sympathomimetics whilst L-DOPA pretreatment and high glucose restore and/or enhance the responses.

Comparative effects of noradrenaline and serotonin in a central and a peripheral artery in vitro.

A comparative study was done on a central and a peripheral artery of the rabbit with noradrenaline, serotonin and K+ in vitro. The aorta was more sensitive to NA than to 5-HT whilst the cerebral artery responded better to 5-HT. In both vessels, K+ produced similar responses. The alpha-adrenoceptor antagonist, phentolamine, and the tryptaminergic receptor antagonists, methysergide and cyproheptadine reduced, competitively, the effects of the agonists. There was no significant difference in the degree of antagonism between the cerebral artery and the thoracic aorta. Potassium-induced contractions were also reversibly reduced by phentolamine but not by 5-HT antagonists. There was no cross-tolerance between 5-HT and noradrenaline and K+ in these arteries. These results indicate that there are differences in the sensitivities of these vessels to the vasoconstrictors. This is interesting in view of the fact that 5-HT has often been implicated in migraine, a central phenomenon.