The association of hypertension with renin-angiotensin system gene polymorphisms in the Lebanese population.

AIM: The study objective was to examine the association of hypertension in the Lebanese population with three renin-angiotensin system gene polymorphisms (RAS): angiotensin-converting enzyme (ACE), angiotensinogen (AGT) and angiotensin-receptor type 1 (AT1R). METHODS: A total of 270 subjects (124 hypertensive vs 146 normotensive) were genotyped for ACE insertion (I)/deletion (D), AGT (M235T), and AT(1)R (A1166C) gene polymorphisms by polymerase chain reaction and restriction fragment length polymorphism. RESULTS: The studied genes showed no deviation from Hardy-Weinberg equilibrium. No association could be reported with the ACE I/D polymorphism, although the D allele frequency was high (77%) in patients. AGT TT genotype prevalence was found to be lower in hypertensive versus normotensive subjects (p<0.0001). AT(1)R CC and AC genotypes were significantly more frequent in hypertensive than normotensive subjects (p<0.0001). CONCLUSION: The first conducted study on the RAS gene polymorphisms in Lebanese hypertensive patients demonstrated a possible association of the AGT T and AT(1)R C alleles with hypertension.

The geographic distribution of the ACE II genotype: a novel finding.

Angiotensin converting enzyme (ACE) gene polymorphism insertion (I) or deletion (D) has been widely studied in different populations, and linked to various functional effects and associated with common diseases. The purpose of the present study was to investigate the relationship between the ACE I/D frequency in different populations and geographic location; ACE I/D allele frequency in the Lebanese population and ACE II genotype contribution to the geographic trend were also identified. Five hundred and seventy healthy volunteers were recruited from the Lebanese population. Genomic DNA was extracted from buccal cells, and amplified by polymerase chain reaction; products were then identified by gel electrophoresis. The frequencies of the different ACE I/D genotypes were determined and tested for Hardy-Weinberg equilibrium (HWE). To assess the relationship between ACE I/D frequency and geographic location, and to identify how the Lebanese population contributes to the geographic trend in ACE I/D frequencies, Eurasian population samples and Asians were incorporated in the analyses from the literature. The frequency of the I allele in the Lebanese population was 27% and the corresponding II genotype was at a frequency of 7.37% (in HWE; P=0.979). The ACE I allele and genotype frequencies show an association with longitude, with frequencies increasing eastwards and westwards from the Middle East.

When does it hurt? Pain during flexible cystoscopy in men.

INTRODUCTION: In this observational study, pain was measured continuously in men undergoing flexible cystoscopy, in order to help to identify which parts of the procedure were the most painful. PATIENTS AND METHODS: Men who were to undergo flexible cystoscopy were recruited. Pain was measured continuously throughout flexible cystoscopy by asking the subject to squeeze a pressure-sensing rubber bulb in proportion to the amount of discomfort experienced giving a score of 0-10. RESULTS: The most painful part of the procedure was as the cystoscope passed through the membranous urethra with a median pain score of 2.82. The initial lidocaine administration gives a median pain score of 0.84. The other parts of the cystoscopy produced median scores of between 0.14 and 0.33. The difference in the pain scores was significant (p = 0.03). There was no statistically significant difference in the pain scores between those who were having their first cystoscopy and those who were having repeat cystoscopy. The subjects' age did not influence the degree of pain experienced. CONCLUSION: This study gives further understanding of how pain is experienced during flexible cystoscopy. It may help explain why previous studies have not reached a clear consensus on the value of lidocaine during flexible cystoscopy.

Effects of age on feeding behavior and chemosensory processing in the pond snail, Lymnaea stagnalis.

This study used behavioral and electrophysiological techniques to examine age-related changes in the feeding behavior and chemosensory processing in the pond snail, Lymnaea stagnalis. Increasing age was associated with a 50% decrease in long-term food consumption. Analysis of short-term sucrose-evoked feeding bouts showed an age-related increase in the number of animals that failed to respond to the stimulus. Of the animals that did respond increasing age was associated with a decrease in the number of sucrose-evoked bites and a increase in the duration of the swallow phase. These changes were observed with both 0.01 and 0.05M sucrose stimuli but were not seen when 0.1M sucrose was used as the stimulus. Electrophysiological analysis of the chemosensory pathway in semi-intact lip-CNS preparations failed to demonstrate a significant change in the neuronal information entering the cerebral ganglia from the lips via the median lip nerve, but did demonstrate an age-related deficit in the neuronal output from the cerebral ganglia. This deficit was also dependent on the sucrose concentration and mirrored the concentration-dependent changes in feeding behavior. In summary, aging appeared to affect central but not peripheral processing of chemosensory information and suggests that this deficit contributes to the age-related changes in feeding behavior.

Strain differences in the anxiolytic effects of losartan in the mouse.

Anxiolytic effects of the angiotensin AT(1) receptor antagonist losartan were studied in the elevated plus maze (EPM) and the light/dark test (LDT) in different mouse strains as were responses to angiotensin II and acetylcholine in isolated ascending colon. There were no significant strain differences in behaviour on the EPM, and diazepam was anxiolytic in C57BL/6, DBA/2 and BKW mice. Losartan was anxiolytic in BKW only. In the LDT, there were significant strain differences, with BKW mice exhibiting greatest anxiety-like behaviour; losartan was ineffective in this test. In vitro responses to angiotensin II and acetylcholine were significantly smaller in BKW than in C57BL/6 and DBA/2. These results indicate that the mouse strain exhibiting least angiotensin receptor function is the most responsive to the anxiolytic effects, suggesting a possible relationship between angiotensin receptor function and anxiolytic response to losartan.

Cytotoxicity and teratogenicity of chlorhexidine diacetate released from hollow nylon fibres.

Intra-uterine contraceptive devices are associated with an increased incidence of pelvic infections, possible due to the introduction of vaginal bacteria into the uterus at insertion. One potential means to overcome this problem is the use of a device which releases the antimicrobial agent chlorhexidine although such an approach carries with it the risk of adverse effects on the endometrium and, possibly, teratogenic effects. Cultured monolayers of endometrial cells were used to assess the cytotoxicity of both chlorhexidine and chlorhexidine-releasing devices. The results indicated that the agent is toxic at concentrations of 1 microg mL(-1) and that the devices potentiated the toxicity. When the devices were tested in a guinea-pig model, endometrial damage was seen only at the high dose of chlorhexidine, suggesting that there is greater distribution of chlorhexidine in-vivo. Assessment of the teratogenic effects of chlorhexidine in rat embryonic limb bud tissue cells in-vitro showed that the foetal cells were highly susceptible to the toxic effects of chlorhexidine, but that there was no evidence of teratogenicity. Overall, the findings suggest that chlorhexidine-releasing devices may be a safe means of reducing infections related to intra-uterine devices, but that the chlorhexidine may have a toxic effect on foetal cells.

Use of chlorhexidine-releasing nylon fibres to reduce device-related uterine infections.

Implantation of intrauterine devices (IUDs) is associated with an increased incidence of uterine infection, probably as a result of vaginal bacteria entering the uterus at the time of insertion. To reduce the incidence of IUD-related infections, the incorporation of antimicrobial agents into the tail of the device was studied. Chlorhexidine was shown to be released from within nylon hollow fibres at a rate of approximately 114 microg x day(-1) for 10 days. This rate of release was sufficient to exhibit a biocidal effect on bacteria embedded within a mucus gel in vitro. When these devices were implanted transcervically into the guinea-pig uterus they significantly reduced the extent of uterine bacterial contamination within 24 h. These findings indicate that chlorhexidine-releasing devices are potentially useful in the reduction of device-related infections.

Evidence of a possible role of altered angiotensin function in the treatment, but not etiology, of depression.

BACKGROUND: Angiotensin-converting enzyme inhibitors are reportedly effective in the treatment of depression; furthermore, antidepressants decrease angiotensin function. It appears therefore that reduced angiotensin function may be important in the treatment of depression. The aims of this study were to elucidate the actions of antidepressants on angiotensin receptors; to investigate the antidepressant potential of an angiotensin antagonist; and to study angiotensin receptors in depressed puerperal women. METHODS: The effects of antidepressant drugs on angiotensin receptors and the relationship between mood and platelet receptors in puerperal women were investigated using radioligand binding. The antidepressant potential of the angiotensin antagonist losartan was assessed using the mouse forced swim test. RESULTS: Desipramine, but neither fluoxetine nor tranylcypromine, displaced angiotensin from its receptor; however, there was no significant relationship between receptor number and depressed mood. In the forced swim test losartan was shown to possess antidepressant like activity. CONCLUSIONS: These findings indicate that antidepressants differ in the mechanism by which they reduce angiotensin function, but the link between antidepressants and angiotensin is reiterated by the demonstration that losartan possesses antidepressant like activity. There is, however, no evidence of abnormal angiotensin receptors in women with depressed mood postpartum.

A standard strain of human ocular keratocytes.

The ability of an injured cornea to regenerate from deep tissue trauma is largely due to wound healing processes mediated by the surviving stromal keratocytes. Despite the importance of the wound healing process, and the ease with which keratocytes can be grown in tissue culture, a standardised strain of the cells has never been made available. Accordingly, this study reports a strain of human embryonic keratocytes, designated EK1.BR as a research tool for the ophthalmic community. EK1.BR has been characterised with respect to life-span, fraction of dividing cells and maintenance of a keratocyte phenotype in culture. It is hoped that these cells will prove useful in the in vitro study of stromal wound healing and the characterisation of keratocyte gene expression.

The development of in vitro biocompatibility tests for the evaluation of intraocular biomaterials.

Recent developments in ocular implant technology require the in vitro evaluation of ocular compatibility in early stage development programs. This requires an understanding and appreciation of the biological interactions which occur in the ocular environment and their relevance with respect to the clinical complications associated with surgical implantation of devices. This paper describes the development of a series of clinically reflective in vitro assays for assessing the potential ocular compatibility of novel intraocular lens materials. Staphylococcus epidermidis attachment, fibrinogen adsorption, mouse embryo fibroblast 3T3 adhesion and proliferation, primary rabbit lens cell adhesion, human peripheral blood macrophage adhesion and granulocyte activation tests were employed to evaluate two widely used intraocular biomaterials poly(methyl methacrylate) (PMMA) and silicone, and a novel biomimetic phosphorylcholine-based coating (PC). The performance of these materials in the in vitro assays was compared to their ability to reduce postoperative inflammation in vivo in a rabbit model. The results demonstrated that the in vitro assays described here are predictive of in vivo ocular compatibility. These assays offer a more relevant means of assessing the ocular compatibility of biomaterials than those presently required by the authorities for regulatory approval of medical devices and implants.

In vitro cytotoxicity and teratogenicity of norethisterone and levonorgestrel released from hollow nylon monofilaments.

Direct delivery of progestogens to the uterus may be of use in the treatment of dysfunctional uterine bleeding and the sequelae of the menopause as it has the potential to overcome the problems of systemic administration. This study characterised the release of norethisterone and levonorgestrel into an aqueous medium from hollow nylon fibres with dimensions suitable for easy insertion through the post-menopausal cervix. Cell culture techniques were used to assess potential cytotoxic and teratogenic effects. The results demonstrated that the hollow fibres released norethisterone and levonorgestrel at mean rates of 0.5 and 0.6 micrograms/day over 14 days, respectively. There were indications, however, that both steroids were toxic to endometrial cells at concentrations of approximately 5 micrograms/ml, and both drugs showed signs of potential teratogenicity at 10 micrograms/ml. Delivery of the same doses of norethisterone using the hollow fibres reduced the effects on the endometrial and fetal cells. Delivery of levonorgestrel from the hollow fibres had no effect on the endometrial cell toxicity but potentiated the effects on the fetal cells. These results suggest that the hollow nylon fibres may be of use for the delivery of norethisterone to the uterus but that they are inappropriate for the delivery of levonorgestrel.

Reduction of responses to angiotensin II by antidepressant drugs.

The effects of the antidepressant drugs desipramine, fluoxetine and tranylcypromine and the non-antidepressant control cocaine on angiotensin II function were determined in vivo by use of angiotensin-induced drinking in rats and in vitro using contractile responses of the rat uterus. The results of the drinking studies showed that the three antidepressants, but not cocaine, reduced the dipsogenic effects of angiotensin II. In vitro, all of the drugs reduced the effects of not only angiotensin but also acetylcholine and oxytocin on the uterus. The inhibition appeared to be non-competitive in all cases. These results indicate that the antidepressant drugs reduced the activity of angiotensin II, albeit non-selectively, and suggest that the previously reported effects of antidepressants on isoprenaline-induced drinking in rats reflect an action on angiotensin activity rather than a reduction of beta-adrenoceptor activity as previously suggested.

The effects of transcervical monofilament insertion on the microbial status of the uterus in guinea-pigs.

The monofilament marker tail attached to intra-uterine contraceptive devices (IUCDs) has been implicated in the development of pelvic infection because it acts as a substrate for bacterial adhesion, and facilitates the transmission of vaginal bacteria into the uterus. A guinea-pig model was used to investigate the role of transcervical monofilaments in the transmission of vaginal bacteria into the uterus. By 21 days the degree of uterine contamination was significantly lower than after 24 h (P < 0.05), but was still significantly greater than control values (P < 0.01). Coating the monofilaments with poly (2-hydroxyethyl-methacrylate) (polyHEMA) had no effect on uterine bacterial counts at 24 h. After 21 days, however, contamination within the uteri fitted with polyHEMA-coated monofilaments had significantly increased from levels observed at 24 h (P < 0.01). These counts were also significantly greater than those recorded for the uncoated and control groups at the same time interval. In animals fitted with monofilaments, in which chlorhexidine had been incorporated into the polyHEMA coating, the level of uterine contamination after 24 h was significantly lower than that observed with uncoated threads at the same time interval (P < 0.02). After 21 days there was no significant difference between uterine bacterial counts from the chlorhexidine group and control animals. It is concluded that the use of such drug-loaded monofilaments offers the potential to minimize infections associated with the transcervical insertion of IUCDs.

The effects of antibiotics and steroids on the carriage of vaginal bacteria into the uterus during insertion of intra-uterine monofilaments in the guinea-pig.

The effects of systemic norethisterone acetate and oxytetracycline hydrochloride on the levels of vaginal microorganisms found in the uterus after the insertion of transcervical, intra-uterine monofilaments in the guinea-pig were determined. The results indicated that bacteria were transferred to the uterus from the vagina during the insertion process and, in the presence of an intra-uterine substrate, persisted for up to 6 months. Daily treatment with norethisterone acetate or oxytetracycline hydrochloride whilst the monofilament was in-situ failed to reduce the bacterial numbers in the uterus. Similarly, daily treatment with oxytetracycline hydrochloride for the 5 days before monofilament insertion had no effect on these bacteria.

Uterine contamination in the guinea pig following transcervical uterine monofilament insertion.

The effects of transcervical, intrauterine monofilaments on guinea pig uterine microflora were determined. The results indicated that bacteria were transferred to the uterus during the insertion process, although in sham control animals these bacteria were eradicated within 10 days. In the presence of an intrauterine substrate the bacteria within the uterus persisted for up to 6 months. Electron micrographs showed that bacteria were adhered to the monofilament within a biofilm, although some bacteria were planktonic.

Effects of steroid hormones and immunosuppressant drugs on defences against uterine microbial contamination in the rat.

This study used rats as a mammalian model to investigate the effects of steroid hormones and immunosuppressant drugs on uterine microflora. It was shown that prednisolone acetate predisposed to uterine contamination unlike oestradiol, ciclosporin and cyclophosphamide. It therefore appears that the leucocyte component of the immune system does not normally play a role in preventing bacterial colonization of the uterus and that prednisolone is producing its effect via some other mechanism, possibly an effect on cervical mucus.

Predisposition to uterine microbial contamination in the guinea-pig following administration of mucolytic drugs and steroid hormones.

Using guinea-pigs as a mammalian model, the effects of bromhexine hydrochloride, ethinyloestradiol, norethisterone acetate and prednisolone acetate on uterine microbial status were determined. Those drugs known to decrease mucus viscoelasticity predisposed to the entry of vaginal bacteria into the uterus, probably due to reduction of the cervical mucus barrier. Norethisterone acetate, which increases cervical mucus viscoelasticity, reduced these effects. The effects produced by the steroid hormones were independent of their immunosuppressive effects. The results also suggest that prednisolone acetate may exert oestrogen-like actions on cervical mucus.

Reduction of salbutamol-induced drinking by putative and proven antidepressants.

Salbutamol-induced drinking was determined in rats after 4 days of twice daily treatment with the conventional and putative antidepressants desipramine, clenbuterol or salbutamol. Drinking was also determined 21 h after a single dose of the abovementioned drugs. Both chronic and acute administration of the drugs resulted in a significant reduction in the salbutamol-induced fluid intake. The results suggest that these drugs decrease beta 2-adrenoceptor activity, but that repeated administration is not a prerequisite for the effect.

Effect of ethamsylate on carrageenan-induced rat paw oedema: a comparison with indomethacin.

1. Ethamsylate (diethylammonium 2,5-dihydroxybenzene sulfonate, Dicynene), a systemic haemostatic agent with an unknown mechanism of action, was tested for anti-inflammatory activity using the carrageenan-induced rat paw oedema test. 2. Ethamsylate was shown to be an effective anti-inflammatory agent with a time course and amplitude of effect similar to that of indomethacin, although the potency was only about 4% of that for indomethacin. 3. When ethamsylate and indomethacin were co-administered they did not show additive effects, suggesting that they do not share a common mode of action. It is proposed that ethamsylate, like indomethacin, may inhibit prostaglandin synthesis. Ulceration produced by indomethacin, it is suggested that it may prove to be a useful addition to, or replacement for, indomethacin in the treatment of inflammatory disorders.

Marketing issues in continuing medical education.

Marketing is an important component of continuing medical education (CME). However, marketing is more than the identification of methods to recover costs of delivering programming. It focuses on meeting the needs and desires of physician participants, identifying an appropriate location, satisfying the goals of a sponsoring institution, and making an effect on the quality of care given by receivers and deliverers of CME. This paper discusses these issues as well as describes results of a survey designed to gather opinions on CME activities from alumni of training programs of a large, referral-based, multispecialty group practice. The data suggest that CME programs should be targeted to certain specialty groups as determined by field of training rather than practice specialty. Physicians' preferences for CME activities held at resort settings should be considered. Finally, participation in CME may itself be a marketing tool for a sponsoring institution to increase referrals.