H. pylori predictors and outcomes among adults undergoing upper endoscopy at a Jamaican teaching hospital: A cross-sectional study

BACKGROUND

Recent data on the prevalence of H. pylori infection in Jamaica are lacking. It is postulated that there has been a decline in the prevalence of H. pylori infection and its associated complications. We determined sociodemographic characteristics, prevalence of H. pylori infection and clinical outcomes among adults undergoing esophagogastroduodenoscopy (EGD) and histology at the University Hospital of the West Indies (UHWI) between May 2018 and December 2020.

MATERIALS AND METHODS

A cross-sectional study of patients (≥18 years old), who underwent EGD and histological evaluation for H. pylori infection, was conducted. Associations of H. pylori positivity and gastric cancer with sociodemographic/clinical variables and endoscopic findings were determined by stepwise logistic regression using backward selection. Unadjusted and adjusted odds ratios with related 95% confidence intervals (Cis) were calculated for H. pylori positivity and gastric cancer status.

RESULTS

There were 323 participants (mean age 58.6 ± 17.8 years, 54.2% females). H. pylori prevalence was 22.2% (n = 70 of 315), 5.6% had gastric neoplasia (GN), 15.5% gastric atrophy, 11.4% intestinal metaplasia and 3.7% dysplasia on histology. Mucositis (64.5%), gastric ulcer (14.9%), and duodenal ulcer (13.9%) were the most common endoscopic findings. Participants with peptic ulcer disease (PUD) (unOR = 4.0; p = .017), gastric cancer (unOR = 9.5; p = .003), gastric atrophy (unOR = 12.8; p < .001), and intestinal metaplasia (unOR = 5.0; p < .001) had a significantly higher odds of being H. pylori positive, but after multivariable analyses only gastric atrophy remained significant (aOR = 27.3; p < .001). Participants with mucositis had a significantly lower odds of gastric cancer (unOR 0.1; p = .035) while participants with dysplasia had significantly higher odds (unOR 8.0; p = .042), but these were no longer significant after multivariable analyses (aOR = 0.2; p = .156 and aOR = 18.9; p = .070, respectively).

CONCLUSIONS

Histology based prevalence of H. pylori infection is lower than previously reported in Jamaica. Gastric atrophy is a significant predictor of H. pylori positivity.

Phenomenological-based constitutive modelling of warm deformation behavior of high-Strength lightweight AL-Li alloy sheets

The flow behavior and formability of Al-Li alloys under warm forming conditions are complicated because they depend on several factors, such as the deformation mode, strain, and strain rates. Therefore, characterizing the mechanical response, and deformation behavior of AA2060-T8 sheets under a wide range of temperatures and strain rates is crucial to develop a new thermo-mechanical processing (TMP) route for their wide industrial applications. Furthermore, determining the activation energy (Q) and predicting the flow behaviour of AA2060-T8 sheets under warm forming temperatures is meaningful for characterizing the mechanical response of AA2060-T8 sheets at warm deformation conditions. Thus, in this study, the Arrhenius constitutive model is developed to investigate the influence of strain rate and temperature on the warm deformation behaviour of AA2060-T8 and determine the activation energy (Q) of AA2060-T8, which is a crucial physical parameter to estimate the difficulties of deforming AA2060-T8 sheets under warm forming conditions.

Risk of malignancy in patients with psoriasis: a 15-year nationwide population-based prospective cohort study in Korea

BACKGROUND

The association between psoriasis and risk of malignancy has not been thoroughly evaluated in a large longitudinal cohort of Asian population.

OBJECTIVE

To determine the long-term risk of malignancy in Korean adult patients with psoriasis.

METHODS

We conducted a nationwide population-based prospective cohort study with a 15-year observational period. During the baseline period (1997-2000), total 1 773 786 Korean subjects who received health insurance from the National Health Insurance System were enrolled and 5788 subjects were defined as a psoriasis group. The number of new-onset malignancy was collected during the observational period (2001-2015).

RESULTS

Patients with psoriasis had a higher adjusted hazard ratio (aHR) for development of overall malignancy [aHR 1.08, 95% confidence interval (CI) 1.00-1.18] and gastric cancer (aHR 1.31, 95% CI 1.08-1.58) compared to controls. The risks of non-Hodgkin lymphoma and non-melanoma skin cancer were significantly increased only in patients with psoriasis who received systemic treatments (aHR 2.86, 95% CI 1.07-7.61 and aHR 3.93, 95% CI 1.47-10.47, respectively).

CONCLUSION

Psoriasis is associated with long-term risk for overall malignancy in Koreans, which was primarily driven by the increased risk of gastric cancer.

Targeted Next-Generation Sequencing for Comprehensive Genetic Profiling of Pharmacogenes

Phenotypic differences in drug responses have been associated with known pharmacogenomic loci, but many remain to be characterized. Therefore, we developed next-generation sequencing (NGS) panels to enable broad and unbiased inspection of genes that are involved in pharmacokinetics (PKs) and pharmacodynamics (PDs). These panels feature repetitively optimized probes to capture up to 114 PK/PD-related genes with high coverage (99.6%) and accuracy (99.9%). Sequencing of a Korean cohort (n = 376) with the panels enabled profiling of actionable variants as well as rare variants of unknown functional consequences. Notably, variants that occurred at low frequency were enriched with likely protein-damaging variants and previously unreported variants. Furthermore, in vitro evaluation of four pharmacogenes, including cytochrome P450 2C19 (CYP2C19), confirmed that many of these rare variants have considerable functional impact. The present study suggests that targeted NGS panels are readily applicable platforms to facilitate comprehensive profiling of pharmacogenes, including common but also rare variants that warrant screening for personalized medicine.

6-Shogaol, an active compound of ginger, alleviates allergic dermatitis-like skin lesions via cytokine inhibition by activating the Nrf2 pathway

Allergic dermatitis (AD) clinically presents with skin erythematous plaques, eruption, and elevated serum IgE, and T helper cell type 2 and 1 (Th2 and Th1) cytokine levels. 6-Shogaol [1-(4-hydroxy-methoxyphenyl)-4-decen-one], a pungent compound isolated from ginger, has shown anti-inflammatory effects, but its inhibitory effects on AD are unknown. The aim of this study was to examine whether 6-shogaol inhibits AD-like skin lesions and their underlying mechanism in vivo and in vitro. An AD-like response was induced by tumor necrosis factor-α (TNF-α)+IFN-γ in human keratinocytes or by 2,4-dinitrochlorobenzene (DNCB) in mice. In vivo, 6-shogaol inhibited the development of DNCB-induced AD-like skin lesions and scratching behavior, and showed significant reduction in Th2/1-mediated inflammatory cytokines, IgE, TNF-α, IFN-γ, thymus and activation-regulated chemokine, IL-1, 4, 12, and 13, cyclooxygenase-2, and nitric oxide synthase levels. In vitro, 6-shogaol inhibited reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPKs) signaling, and increased the levels of total glutathione, heme oxygenase-1, and quinone 1 via nuclear factor erythroid 2 related factor 2 (Nrf2) activation. 6-Shogaol can alleviate AD-like skin lesions by inhibiting immune mediators via regulating the ROS/MAPKs/Nrf2 signaling pathway, and may be an effective alternative therapy for AD.

A Review of Pharmacovigilance

Pharmacovigilance supports safe and appropriate use of drugs. Spontaneous reporting of adverse drug reactions (ADRs) is an essential component of pharmacovigilance. However, there is significant underreporting of ADRs. Adverse drug reactions have become a major problem in developing countries. Knowledge of pharmacovigilance could form the basis for interventions aimed at improving reporting rates and decreasing ADRs.

Clinical Factors Associated with Morbidity and Mortality in Patients Admitted with Sickle Cell Disease

OBJECTIVE

To determine the clinical factors associated with the length of hospitalization and mortality in patients with sickle cell disease (SCD).

METHODS

All patients with SCD admitted to the medical wards of the University Hospital of the West Indies, Jamaica, over a five-year period, January 1 to December 31, 2010, were reviewed. Data were extracted from hospital charts and comprised demographic and clinical information, investigations, interventions, duration of stay, pathological data and outcomes.

RESULTS

There were 105 patients reviewed; 84% were genotype Hb SS. Females accounted for 59% and males 41%. Overall mean age was 32.5 years (SD 13.7, range 12-66 years). The mean length of hospitalization was 10.2 days (SD 10.9, range 1-84 days). The main admission diagnoses were painful crisis, acute chest syndrome, severe anaemia, sepsis, hepatic sequestration, congestive cardiac failure and renal failure. The mean value for the following laboratory investigations were: haemoglobin 7.7 g/dL (SD 2.8), total white blood cell count 21.7 x 109/L (SD 14.2), platelet count 320 x 109/L (SD 191.9), blood urea 9.8 mmol/L (SD 11.9) and serum creatinine 198 umol/L (SD 267.9). Medical interventions included: blood transfusions in 20.9%, 55% received antibiotics and 74% received narcotic analgesia. There were 40 deaths with four autopsies done. The mortality rate for SCD was 38%. There were 189 repeat SCD admissions.

CONCLUSION

Sickle cell disease still carries a high morbidity and mortality in patients admitted to hospital. Recurrent admissions are a concern, as they impact on patient's morbidity and quality of life.

Vitamin D levels in Jamaican patients with systemic lupus erythematosus

Vitamin D has important effects on the immune system as it has been shown to exert antiproliferative and relative immunosuppressant effects. Low levels of this hormone may contribute to the immune activation in systemic lupus erythematosus (SLE) and other autoimmune diseases. Serum levels of 25-OH vitamin D were measured in 75 patients with SLE in Jamaica, using an enzyme-linked immunoassay. Correlations with clinical data and disease activity as determined by the BILAG index were determined. Of a total of 75 patients, 33 (44%) had vitamin D sufficiency with mean vitamin D level of 39.45 ng/ml (range, 30.35-58.16). Forty-two (56%) patients had either vitamin D deficiency or insufficiency, 30 (40%) had vitamin D insufficiency, mean 26.36 ng/ml (range, 20.26-29.88), and 12 (16%) had vitamin D deficiency, mean 16.07 ng/ml (range, 7.78-19.90). There was an overall negative relationship between the total disease activity score using the BILAG index and vitamin D levels, and this was influenced primarily by the relationship seen among the vitamin D-deficient subgroup. This was also impacted on by a patient population that was significantly skewed toward low disease activity. The negative association trended toward statistical significance. Vitamin D deficiency is prevalent among patients with SLE in Jamaica. A relationship between low serum levels of vitamin D and SLE activity may occur.

Effects of high positive end-expiratory pressure on haemodynamics and cerebral oxygenation during pneumoperitoneum in the Trendelenburg position

We investigated the effects of 10 cmH2O positive end-expiratory pressure on cerebral haemodynamics and cerebral oxygenation in patients undergoing laparoscopic lower abdominal surgery in the 30° Trendelenburg position during desflurane anaesthesia. Twenty-six patients were enrolled in this study. After anaesthesia induction, pneumoperitoneum was applied in Trendelenburg position. Twenty minutes later, positive end-expiratory pressure was applied. There was no change in regional cerebral oxygen saturation (p = 0.376). Cerebral perfusion pressure decreased significantly over time (p < 0.001) and positive end-expiratory pressure caused a further decrease in cerebral perfusion pressure (p = 0.036). The application of 10 cmH2O positive end-expiratory pressure during pneumoperitoneum in the Trendelenburg position preserved regional cerebral oxygen saturation, but cerebral perfusion pressure decreased significantly due to its secondary haemodynamic effects.

Klippel-Trenaunay syndrome

Klippel-Trenaunay syndrome (KTS) is a rare congenital, vascular disorder affecting one or more limbs. The syndrome is characterized by capillary malformations, soft tissue or bony hypertrophy and varicose veins or venous malformations. We present a case of this disorder in a twelve-year old boy who had an enlarged right lower limb with varicosities. Investigations revealed extensive superficial and deep venous varices, with dilatation of the right common iliac and external iliac veins. Klippel-Trenaunay syndrome should be suspected in a child presenting with capillary haemangioma and an enlarged limb.

ε-Acetamidocaproic acid pharmacokinetics in rats with gastric ulcer or small bowel inflammation

The pharmacokinetics of ϵ-acetamidocaproic acid (AACA) were evaluated after the intravenous and oral administration of an antiulcer agent, zinc acexamate (ZAC) at a dose of 20 mg kg⁻¹ (ion pairing between zinc and AACA) in rats with indomethacin-induced acute gastric ulcer (IAGU) or indomethacin-induced small bowel inflammation (ISBI). In IAGU rats, the area under the curves (AUCs) of AACA were significantly smaller after both the intravenous (551 versus 1270 μg min ml⁻¹) and oral (397 versus 562 μg min ml⁻¹) administration of ZAC than controls, possible due to the significantly faster CL(R) of AACA. In ISBI rats, however, the AUCs of AACA were comparable with controls after both the intravenous and oral administration of ZAC. In IAGU rats, the significantly smaller AUCs of AACA were due to the significantly faster CL(R) (due to the decreased urinary pH by indomethacin treatment) than controls. AACA has a basic secondary amine group. On the other hand, the comparable AUCs of AACA in ISBI rats were due to the comparable CL(R)s between ISBI and control rats. AACA was excreted in the urine via active renal tubular secretion in all rats studied.

Peutz-Jeghers syndrome

Peutz-Jeghers Syndrome (PJS) is an autosomal dominant colonic polyposis syndrome. It is a rare condition but is of importance because of the risk of gastrointestinal as well as extraintestinal malignancies and the high penetrance in the family linkage. There has been no report of this condition in the Caribbean. We report a 32-year old male who presents with a history of rectal bleeding on a background history of having colonic polyps. Colonoscopy revealed multiple large colonic polyps with partial obstruction in the descending colon. The histology revealed hamartomatous Peutz-Jeghers polyps. Peutz-Jeghers Syndrome is an important consideration in a young patient with colonic polyps.

Propofol sedation in patients undergoing colonoscopy in Jamaica

BACKGROUND

Propofol sedation is increasingly used for colonoscopy and may be associated with increased satisfaction and efficiency in diagnostic and therapeutic endoscopy. However propofol has a relatively narrow therapeutic window as it frequently produces deep sedation, and can precipitate respiratory depression.

AIM

To determine the efficacy, safety and patient satisfaction with propofol sedation in patients undergoing colonoscopy at the University Hospital of the West Indies (UHWI).

METHODS

Patients undergoing outpatient colonoscopy at the UHWI who were sedated with propofol were studied. Boluses of 10 - 20 mg of propofol at intervals of 2 - 5 minutes, as needed for adequate sedation, were administered after initial induction. Continuous monitoring of the pulse rate, and oxygen saturation were performed and the blood pressure checked every 2 - 5 minutes. All patients received supplemental oxygen (4 L/min). The following observations were recorded: the endoscopist recorded the ease of the procedure, the anaesthetist recorded the comfort of the patient throughout the procedure and at the time of discharge, and the patient stated the degree of satisfaction with the procedure. Any unusual events were recorded.

RESULTS

Sixty consecutive patients sedated with propofol were studied. There were 28 (46.7%) males, with a mean age of 58.3 years and 32 (53.3%) females, with mean age of 59.5 years. Most were normal healthy patients (56.6%). Comorbid illnesses were present in 43.4%, with hypertension being most common (23.3%). All patients were classified as ASA class 1 and 2. The average dose of propofol used was 180 mg (range 50 - 355 mg). The mean duration of colonoscopy was 19.5 minutes. The mean recovery period (able to stand) was 29.6 minutes. There were no documented cases of significant hypotension, bradycardia, or hypoxaemia during the procedure. Transient apnoeic episodes during the initial stages of sedation occurred in 12 (20%) patients. The majority of patients (91.7%) rated the experience as being extremely good or excellent. The majority could not recall the actual colonoscopy and there were minimal subjective reports of nausea or discomfort during the procedure.

CONCLUSIONS

Propofol sedation was associated with quick recovery and excellent satisfaction by patients and is a suitable alternative for sedation for colonoscopy in Jamaica.

Upper gastrointestinal bleeding: a Jamaican perspective

BACKGROUND

Upper gastrointestinal bleeding (UGIB) remains one of the most common clinical life-threatening emergencies which is associated with a high morbidity, mortality and medical care costs.

OBJECTIVES

This study reviews the clinical features, management and outcomes of patients with UGIB seen at the University Hospital of the West Indies (UHWI), Jamaica, between January 2006 and December 2008.

METHODS

Patients with UGIB admitted to the medical wards of the UHWI, Jamaica, between January 2006 and December 2008 were reviewed. Consecutive patients admitted with a confirmed diagnosis of UGIB were selected for analysis. Data collected included age, gender presenting complaints, risk factors, clinical features and management. Endoscopic findings, treatment and outcomes were also reviewed.

RESULTS

There were 104 patients, with a mean age of 55 years, admitted with UGIB. There were significantly more men than women (73 vs 31). Retching and vomiting were the most common presenting complaints followed by melaena and haemetemesis. Non-steroidal anti-inflammatory drug use was present in 28% of patients. Overall, 80% of patients had upper GI endoscopy (EGD) and 40% were done within 24 hours of admission. The median time for performing EGD was 24 hours (mean 46 hours). The leading causes of UGIB were duodenal ulcer (28%), erosive gastritis (20%) and gastric ulcer (13%). Proton pump inhibitors (PPI) were given to 95 (91%) patients intravenously. Blood transfusion was given to 40% of patients. The mortality was 5.7%, rebleeding occured in 4.8% of patients and 5% underwent surgery. The average duration of hospital stay was 6.6 days.

CONCLUSION

Upper gastrointestinal bleeding was more common in men of middle age in this study. Proton pump inhibitors were used in most patients. The overall mortality of 5.7% is similar to other series. Early EGD and use of endoscopic therapy may lead to a decrease in mortality in high risk patients.

Effect of Replens vaginal moisturiser on latex rubber condoms: a comparison with oil and water based preparations

The effect of Replens vaginal moisturiser on the tensile properties of latex rubber condoms was compared with that of baby oil, K-Y jelly, Nystan cream and Duracreme. The tensile strength and elongation at break of test pieces cut from condoms were measured after immersion in each of the test products for five minutes. The tensile properties of the latex was unaffected after treatment with Replens. K-Y jelly, Duracreme and Replens produced similar results.

Association of ABCB1 polymorphisms with the efficacy of ondansetron for postoperative nausea and vomiting

We investigated whether the 2677G>T/A and 3435C>T polymorphisms of adenosine triphosphate-binding cassette subfamily B member 1 (ABCB1) affect the efficacy of ondansetron to prevent postoperative nausea and vomiting. One hundred and ninety-eight patients undergoing general anaesthesia were enrolled. Thirty minutes before the end of surgery, 0.1 mg.kg⁻¹ ondansetron was administered intravenously. The incidence of postoperative nausea and vomiting was compared between genotypes in the 2677G>T/A and 3435C>T polymorphisms of ABCB1. The incidence of postoperative nausea and vomiting was lower in patients with the 2677TT genotype (TT vs Non-TT = 25.9% vs 53.0%, p = 0.01) and 3435TT genotype (CC + CT vs TT = 52.6% vs 21.7%, p = 0.01) during the first 2 h after surgery. There were no significant differences in the incidence of postoperative nausea and vomiting between the different genotype groupings during period between 2 and 24 h after surgery. In conclusion, ABCB1 genotypes may be a clinical predictor of responsiveness for ondansetron.

Pharmacokinetic interaction between itraconazole and metformin in rats: competitive inhibition of metabolism of each drug by each other via hepatic and intestinal CYP3A1/2

BACKGROUND AND PURPOSE

Fungal infection is prevalent in patients with diabetes mellitus. Thus, we investigated whether a pharmacokinetic interaction occurs between the anti-fungal agent itraconazole and the anti-glycaemic drug metformin, as both drugs are commonly administered together to diabetic patients and are metabolized via hepatic CYP3A subfamily in rats.

EXPERIMENTAL APPROACH

Itraconazole (20 mg·kg(-1)) and metformin (100 mg·kg(-1)) were simultaneously administered i.v. and p.o. to rats. Concentrations (I) of each drug in the liver and intestine, maximum velocity (V(max)), Michaelis-Menten constant (K(m)) and intrinsic clearance (CL(int) ) for the disappearance of each drug, apparent inhibition constant (K(i) ) and [I]/K(i) ratios of each drug in the liver and intestine were determined. Also the metabolism of each drug in rat and human CYPs was measured in vitro.

KEY RESULTS

After simultaneous administration of both drugs, either i.v. or p.o., the total area under the plasma concentration-time curve from time zero to infinity (AUC)s of itraconazole and metformin were significantly greater than that of either drug administered alone. The metabolism of itraconazole and metformin was significantly inhibited by each other via CYP3A1 and 3A2 in rat and 3A4 in human microsomes.

CONCLUSIONS AND IMPLICATIONS

The significantly greater AUCs of itraconazole and metformin after i.v. administration of both drugs are probably due to competitive inhibition of the metabolism of each drug by each other via hepatic CYP3A1/2. Whereas after oral administration of both drugs, the significantly greater AUCs of each drug administered together than that of either drug alone is mainly due to competitive inhibition of intestinal metabolism of each drug by each other via intestinal CYP3A1/2.

Pharmacokinetics of sildenafil and its metabolite, N-desmethylsildenafil, in rats with liver cirrhosis and diabetes mellitus, alone and in combination

Pharmacokinetics of sildenafil and its metabolite, N-desmethylsildenafil, in humans and rats with liver cirrhosis (LC) and diabetes mellitus (DM), alone and in combination (LCD) did not seem to be reported. Sildenafil was administered intravenously (10 mg/kg) and orally (20 mg/kg) to control, LC, DM, and LCD rats. Expression of intestinal CYP isozymes in those rats was also measured. In LC, DM, and LCD rats, the areas under the curve (AUCs) of intravenous sildenafil were significantly greater (by 195%, 54.2%, and 127%, respectively) than controls. In LC and LCD rats, AUCs of oral sildenafil were significantly greater (3010% and 2030%, respectively) than controls. In LC, DM, and LCD rats, significantly greater AUCs of intravenous sildenafil were due to the slower hepatic extraction of sildenafil (because of decrease in the protein expression of hepatic CYP2C11 and 3A subfamily in LC and LCD rats, and CYP2C11 in DM rats). In LC and LCD rats, greater magnitude of increase in AUCs of oral sildenafil than those after the intravenous administration could be mainly due to the decrease in the intestinal extraction of sildenafil (because of decrease in the protein expression of intestinal CYP2C11 in LC and LCD rats).

Pregnenolone sulfate enhances spontaneous glutamate release by inducing presynaptic Ca2+-induced Ca2+ release

Pregnenolone sulfate (PS) acts as an excitatory neuromodulator and has a variety of neuropharmacological actions, such as memory enhancement and convulsant effects. In the present study, we investigated the effect of PS on glutamatergic spontaneous excitatory postsynaptic currents (sEPSCs) in acutely isolated dentate gyrus (DG) hilar neurons by use of a conventional whole-cell patch-clamp technique. PS significantly increased sEPSC frequency in a concentration-dependent manner without affecting the current amplitude, suggesting that PS acts presynaptically to increase the probability of spontaneous glutamate release. However, known molecular targets of PS, such as α7 nicotinic ACh, NMDA, σ1 receptors and voltage-dependent Ca(2+) channels, were not responsible for the PS-induced increase in sEPSC frequency. In contrast, the PS-induced increase in sEPSC frequency was completely occluded in a Ca(2+)-free external solution, and was significantly reduced by either the depletion of presynaptic Ca(2+) stores or the blockade of ryanodine receptors, suggesting that PS elicits Ca(2+)-induced Ca(2+) release (CICR) within glutamatergic nerve terminals. In addition, the PS-induced increase in sEPSC frequency was completely occluded by transient receptor potential (TRP) channel blockers. These data suggest that PS increases spontaneous glutamate release onto acutely isolated hilar neurons via presynaptic CICR, which was triggered by the influx of Ca(2+) through presynaptic TRP channels. The PS-induced modulation of excitatory transmission onto hilar neurons could have a broad impact on the excitability of hilar neurons and affect the pathophysiological functions mediated by the hippocampus.

Characterization of liver metastases: the efficacy of biphasic magnetic resonance imaging with ferucarbotran-enhancement

AIM

To retrospectively evaluate the efficacy of biphasic magnetic resonance imaging (MRI) of the liver with ferucarbotran-enhancement for the characterization of hepatic metastases.

MATERIALS AND METHODS

Thirty-six patients underwent MRI of the liver with separate acquisition of double-contrast enhancement consisting of gadolinium and ferucarbotran. A total of 106 focal hepatic lesions (51 metastases, 31 cysts, 23 haemangiomas, and one eosinophilic abscess) were included. Two sets of MRI were analysed: (1) ferucarbotran set: ferucarbotran-enhanced T1-weighted (T1W) dynamic imaging combined with ferucarbotran-enhanced T2*-weighted (T2*W) delayed imaging and (2) double set: gadolinium-enhanced T1W dynamic imaging combined with ferucarbotran-enhanced T2*W delayed imaging. The diagnostic accuracy of the two sets was evaluated using alternative free-response receiver operating characteristic curve analysis. Sensitivity and specificity were compared using the McNemar test. The enhancement pattern of focal hepatic lesions was analysed on gadolinium and ferucarbotran-enhanced T1W dynamic imaging.

RESULTS

There was no significant difference in the accuracy of characterizing hepatic metastases between the two sets. Sensitivity and specificity were not significantly different between the sets (p>0.05). Peripheral rim enhancement was exhibited in 57% of metastatic lesions on ferucarbotran-enhanced T1W dynamic imaging. The majority (96%) of hepatic haemangiomas demonstrated typical peripheral nodular enhancement with progression on ferucarbotran-enhanced T1W dynamic imaging and were easily differentiated from metastases.

CONCLUSION

Biphasic MRI of the liver with ferucarbotran-enhancement alone provided comparable diagnostic efficacy to double-contrast MRI for the characterization of hepatic metastases.

The prevalence of Helicobacter pylori infection in patients undergoing upper gastrointestinal endoscopy in the Turks and Caicos Islands

BACKGROUND

Helicobacter pylori infection remains a common problem and previous studies in the Caribbean revealed infection in over 50% of patients undergoing upper endoscopy.

OBJECTIVE

The present study determined the prevalence of H pylori infection in patients undergoing upper gastrointestinal endoscopy in the Turks and Caicos Islands over a two- year interval.

METHODS

All patients with upper gastrointestinal symptoms requiring endoscopy were evaluated clinically and H pylori testing performed histologically.

RESULTS

There were 57 patients (21 males, 36 females) with a mean age of 43 years. Twenty-six patients presented with gastroesophageal reflux, 17 with upper abdominal pain, 10 with dyspepsia and 4 with upper gastrointestinal bleeding. H pylori infection was present in 24 patients (42%) and negative in 33 (58%). Upper gastrointestinal endoscopy was normal in 27 patients, 13 (54%) were H pylori positive and 14 (43%) negative. Antral gastritis was present in 13 patients, 7 (54%) were H pylori positive and 6 (46%) negative. Duodenal ulcer was present in 6 (33% H pylori positive) and gastric ulcer in 5 patients (40% H pylori positive). Distal oesophagitis was present in 5 patients (all negative for H pylori) and gastric carcinoma in 1 (H pylori positive).

CONCLUSION

In patients with dyspepsia, 60% were positive for H pylori. H pylori infection was common in the patients in this study with gastrointestinal symptoms. However, the prevalence in endoscopic patients and peptic ulcer disease is lower than in other reports from the Caribbean.

Juvenile polyposis syndrome

Juvenile polyposis syndrome (JPS) is rare and is present when there are multiple juvenile polyps in the gastrointestinal tract, usually the colon. The importance of this condition is the association with the development of colorectal and upper gastrointestinal cancer at a young age. We report the case of a 21-year old male with a two-year history of intermittent rectal bleeding and anal protrusion. Colonoscopy revealed multiple pedunculated cherry red polyps mainly in the left colon. Histology confirmed juvenile polyps. Juvenile polyposis syndrome should be considered in young patients with colonic symptoms, especially rectal bleeding. It is important to distinguish between patients with JPS and patients with an isolated harmatomatous juvenile polyp.

Prevalence of needlestick injuries and other high risk exposures among healthcare workers in Jamaica

OBJECTIVE

To assess the prevalence of needlestick injuries (NSIs) and other high risk exposures among healthcare workers at two hospitals in Jamaica.

METHODS

Employing a cross-sectional study design, medical personnel (physicians, nurses) at two hospitals in Jamaica, were studied, utilizing a structured questionnaire consisting of 14 items to collect data on needle stick injuries and other injuries.

RESULTS

There were 67 needlestick injuries in 47 persons. Of those sustaining an injury, 52% of physicians and 40% of nurses had NSIs. Re-capping needles accounted for 21% of injuries, various minor procedures, 21%, injury during surgery, 19.4% and taking blood, 12%. In those sustaining NSIs, 47% were reported and 26% of reported cases received counselling. Appropriate blood tests were performed on 34% and post-exposure prophylaxis (PEP) for HIV was administered to 30%. Hollow bore needles caused 47.8% of injuries, 25.4% occurred with suture needles and 19.4% with intravenous branulas. Other occupational exposure was reported by 31%, including blood on hands and other body parts 39%, blood to face and eyes, 18%, splashed with liquor, 18%, splashed with bloody fluid, 11% and contact with vomitus and urine in eye, 4%.

CONCLUSION

Needlestick injuries and other high risk exposures were high; incident reporting and post exposure management were inadequate. A comprehensive programme to address factors that contribute to the occurrence of NSIs and other occupational exposures is urgently needed.

Febrile neutropaenia in cancer patients

BACKGROUNDS

Febrile neutropaenia is a common complication of chemotherapy in cancer patients. Empirical antibiotic regimes are based on the epidemiological characteristics of bacterial isolates globally and locally.

METHOD

This study retrospectively reviewed all cases of febrile neutropaenia in patients with confirmed cancer admitted at the University Hospital of the West Indies in the four-year period between, January 1, 2003 and December 31, 2006 and who received chemotherapy. Cases were identified from blood culture records and hospital charts which were reviewed to determine the aetiological agents causing bacteraemia, their antimicrobial susceptibilities and clinicalfeatures. These cases were compared with non-neutropaenic cancer patients admitted with fever.

RESULTS

A total of 197 febrile episodes in cancer patients were reviewed. Thirty-seven per cent had febrile neutropaenia while 62% were non-neutropaenic. Acute myeloid leukaemia was the most common haematological malignancy and the most common solid tumour was breast cancer. Twenty-six per cent of patients had a positive blood culture. In febrile neutropaenic patients, Escherichia coli was the most common organism isolated followed by coagulase-negative staphylococci while in non-neutropaenic patients, coagulase-negative staphylococci was most common. Acinetobacter infections was prominent in non-neutropaenic patients but absent in neutropaenic patients. More than one organism was cultured in 9 neutropaenic and 18 non-neutropaenic patients. Mortality was 10.8% in neutropaenic and 24.4% in non-neutropaenic patients.

CONCLUSION

Gram-negative organisms are the predominant isolates in febrile neutropaenic episodes in this cohort of patients. Non-neutropaenic patients had an increased mortality with an increase in Acinetobacter infections and multiple isolates.

Knowledge and practice of occupational infection control among healthcare workers in Jamaica

OBJECTIVE

To assess the knowledge, compliance and practice among healthcare workers of occupational infection control at two hospitals in Jamaica.

METHODS

Employing a cross-sectional study design, medical personnel (physicians and nurses) at two hospitals in Jamaica, were studied, utilizing a structured questionnaire consisting of 14 items to collect the data.

RESULTS

Participants considered the following fluids, not blood stained, high risk for HIV transmission: breast milk (79%), saliva (14%), urine (27%), pleural fluid (53%), CSF (55%), synovial fluid (37%), faeces (27%), peritoneal fluid (53%) and vomitus (21%). The respondents estimated the risk of transmission of infection after a needlestick injury from a patient with: HIV, mean 22.5%, HB, 34% and HCV, 26%. Needles for drawing blood were identified as having the highest risk for transmission of infections in 63%. The following precautions were adhered to all the time: wearing gloves (38%), not re-sheathing needles (22%), not passing needles directly to others (70%), properly disposing of sharps (86%) and regarding patients' blood and other high risk fluid as potentially infected (62%). Post exposure, 43% indicated bleeding/squeezing the NSI site as the initial first-aid procedure, washing with soap and water (29%) and irrigating the area with water (20%).

CONCLUSIONS

Healthcare workers are aware of the risk of transmission of infection, however compliance with universal precautions was inadequate. An improvement in knowledge and practice with clear guidelines are needed and a comprehensive programme to educate HCWs regarding compliance with universal precautions is urgently required.

Pharmacokinetics of oltipraz in diabetic rats with liver cirrhosis

BACKGROUND AND PURPOSE

The incidence of diabetes mellitus is increased in patients with liver cirrhosis. Oltipraz is currently in trials to treat patients with liver fibrosis and cirrhosis induced by chronic hepatitis types B and C and is primarily metabolized via hepatic cytochrome P450 isozymes CYP1A1/2, 2B1/2, 2C11, 2D1 and 3A1/2 in rats. We have studied the influence of diabetes mellitus on pharmacokinetics of oltipraz and on expression of hepatic, CYP1A, 2B1/2, 2C11, 2D and 3A in rats with experimental liver cirrhosis.

EXPERIMENTAL APPROACH

Oltipraz was given intravenously (10 mg x kg(-1)) or orally (30 mg x kg(-1)) to rats with liver cirrhosis induced by N-dimethylnitrosamine (LC rats) or with diabetes, induced by streptozotocin (DM rats) or to rats with both liver cirrhosis and diabetes (LCD rats) and to control rats, and pharmacokinetic variables measured. Protein expression of hepatic CYP1A, 2B1/2, 2C11, 2D and 3A was measured using Western blot analysis.

KEY RESULTS

After i.v. or p.o. administration of oltipraz to LC and DM rats, the AUC was significantly greater and smaller, respectively, than that in control rats. In LCD rats, the AUC was that of LC and DM rats (partially restored towards control rats). Compared with control rats, the protein expression of hepatic CYP1A increased, that of CYP2C11 and 3A decreased, but that of CYP2B1/2 and 2D was not altered in LCD rats.

CONCLUSIONS AND IMPLICATIONS

In rats with diabetes and liver cirrhosis, the AUC of oltipraz was partially restored towards that of control rats.

Epibulbar complex choristoma and hemimegalencephaly in linear sebaceous naevus syndrome

Epidermal naevus syndrome is a group of congenital syndromes comprising epidermal naevi associated with a variety of developmental abnormalities of the ocular, nervous, skeletal, cardiovascular and urogenital systems. We describe a case of an 8-month-old boy with a brown alopecic plaque on his face and scalp and a vascularized epibulbar mass involving the entire cornea, which had been present since birth. Histopathological examination identified sebaceous naevus in combination with complex choristoma. Magnetic resonance imaging of the brain showed hemimegalencephaly.

A national survey on the practice and outcomes of mechanical ventilation in Korean intensive care units

A study was undertaken to describe the practice and outcomes of mechanical ventilation throughout Korea. This prospective cohort study was conducted over a three-month period enrolling patients (n = 519) who received mechanical ventilation for more than 72 hours in 21 university hospital intensive care units throughout Korea. The most common indication for mechanical ventilation was acute respiratory failure. The most common cause of acute-on-chronic respiratory failure was tuberculous lung disease. The most common initial mode for ventilation was volume-controlled ventilation. The mean tidal volume of acute respiratory distress syndrome patients was 7.6 ml/kg of the predicted body weight and the mean positive end-expiratory pressure was 9.4 cmH20. The weaning success rate at 28 days was 50.3%. Pressure support and the T-piece were most commonly used as initial and final weaning modes respectively. Preventive measures against deep vein thrombosis during mechanical ventilation were performed more frequently in intensive care units with full-time critical care physicians than those without such physicians. Multivariate analysis showed that the APACHE II score, indication for mechanical ventilation, respiratory rate at 72 hours, enteral feeding and prophylaxis of deep vein thrombosis were prognostic factors for survival. In Korean intensive care units, tuberculous lung disease remains an important cause for mechanical ventilation. The practice of mechanical ventilation in Korean intensive care units in general appeared to comply with the current international recommendations with regard to lung protection and weaning. However, intensive care units lacking critical care physicians seemed to be adopting fewer ancillary measures, such as deep vein thrombosis prophylaxis.

Interaction between udenafil and tamsulosin in rats: non-competitive inhibition of tamsulosin metabolism by udenafil via hepatic CYP3A1/2

BACKGROUND AND PURPOSE

Orthostatic hypotension has been observed when PDE 5 (cGMP-specific phosphodiesterase type 5) inhibitors are co-administered with alpha-adrenoceptor antagonists. Here we assessed the pharmacokinetic and haemodynamic interactions between udenafil and tamsulosin in rats, as both drugs are metabolized via rat hepatic cytochrome P450 3A1/2.

EXPERIMENTAL APPROACH

Interactions between the two drugs were evaluated in rats after simultaneous 1 or 15 min i.v. infusion or after p.o. administration of udenafil (30 mg x kg(-1)) and/or tamsulosin (1 mg x kg(-1)). In vitro metabolism of tamsulosin with udenafil was measured to obtain the inhibition constant (K(i)) and [I]/K(i) ratio of udenafil.

KEY RESULTS

The total area under the plasma concentration-time curve from time zero to time infinity (AUC)s (or AUC(0-4 h)) of tamsulosin were significantly greater after 15 min of i.v. infusion or after oral administration with udenafil, compared with tamsulosin alone. The hepatic first-pass metabolism of tamsulosin was inhibited by udenafil, and the inhibition in vitro was in a non-competitive mode. The arterial systolic blood pressure was significantly lower at 5, 10 and 60 min after oral co-administration of the drugs.

CONCLUSIONS AND IMPLICATIONS

The significantly greater AUC of tamsulosin after i.v. and p.o. administration of both drugs may be attributable to non-competitive inhibition of cytochrome P450 3A1/2-mediated hepatic tamsulosin metabolism by udenafil. The inhibition was also observed in human liver S9 fractions, suggesting that a reassessment of the oral dosage of tamsulosin is necessary when udenafil and tamsulosin are co-administered to patients with benign prostatic hyperplasia.

Estimating the market for tuberculosis drugs in industrialized and developing nations

BACKGROUND

The successful introduction of new drugs into low- and middle-income countries requires an understanding of the existing market size and market dynamics for the therapeutic area of interest. The drug markets in these countries are, however, less well understood than those in high-income countries.

METHODS

The global market for tuberculosis (TB) drugs was estimated by studying in detail six high-burden countries and four high-income countries, followed by extrapolation. Data were derived from existing pharmaceutical audit databases and interviews with government officials, medical staff and suppliers.

RESULTS

The use of qualitative inputs to inform the collection of quantitative information, notably to identify where the major flows of TB drugs are located, allowed a confident estimate of the global market for first-line TB drugs. Final ranges were US$261-316 million or US$310-418 million, depending on whether case notification rates or incidence were used for extrapolations.

CONCLUSIONS

An estimation of the global TB drug market is made more reliable by a qualitative understanding of TB drug distribution pathways, which differ greatly among countries. The understanding of this structure in key high-burden countries provides the basis for a simpler update of the market estimate in the future.

Acetaminophen overdose in Jamaica

Acetaminophen is a dose dependent hepatotoxin which is frequently associated with intentional self-harm. Forty-nine cases of parasuicide attempts involving paracetamol only or in combination with another drug were treated at the UHWI, Jamaica, between 1994-2004. The majority were women (84%) and the mean age was 23 years. Acetaminophen was the only agent ingested in 71% of cases; 29% involved an additional drug. Patients presented an average of 6.5 hours after ingestion (range 1-45 hours). Serum transaminases were elevated in 18% of cases and N-acetylcysteine (NAC) therapy given in 55%. The mean duration of hospitalization was three days. One patient developed liver failure and there were no deaths. Education of the public and medical profession is needed to increase awareness of the potential toxic effects of acetaminophen overdose. N-acetylcysteine therapy should be given early in suspected cases.

Heterogeneity in the processing defect of SLC26A4 mutants

BACKGROUND

Mutations in the SLC26A4 gene are responsible for Pendred syndrome and non-syndromic hearing loss (DFNB4). This study analysed non-synonymous SLC26A4 mutations newly identified in East Asians, as well as three common mutations in Caucasians, to characterise their molecular pathogenic mechanisms and to explore the possibility of rescuing their processing defects.

METHODS

A total of 11 non-synonymous disease associated mutations were generated and their effects on protein processing and on ion transporting activities were examined.

RESULTS

Most of the mutations caused retention of the SLC26A4 gene product (pendrin) in the intracellular region, while wild-type pendrin reached the plasma membrane. Accordingly, these mutations abolished complex glycosylation and Cl(-)/HCO(3)(-) exchange activities of pendrin. However, significant heterogeneity in the processing of mutant pendrin molecules was observed. Each mutant protein exhibited a different cellular localisation, a different degree of N-glycosylation, and a different degree of sensitivity to the treatments that rescue processing defects. For example, H723R-pendrin, the most common mutation in East Asians, was mostly expressed in endoplasmic reticulum (ER), and its defects in protein processing and ion transporting activities were restored considerably by low temperature incubation. On the other hand, L236P-pendrin, the most common mutation in Caucasians, was mainly in the centrosomal region and was temperature insensitive.

CONCLUSION

These results indicate that the processing of pendrin mutant protein is determined by mutant specific mechanisms, and that a mutant specific method would be required to rescue the conformational defects of each folding mutant.

Pharmacokinetic interaction between DA-8159, a new erectogenic, and metformin in rats: competitive inhibition of metabolism via hepatic CYP3A1/2

BACKGROUND AND PURPOSE

Erectile dysfunction is highly prevalent in diabetic patients and PDE V inhibitors are effective and safe for the treatment of erectile dysfunction in men with diabetes. Therefore, in this study we investigated whether a pharmacokinetic interaction occurs between DA-8159 and metformin, as both drugs are metabolized via hepatic CYP3A1/2 in rats.

EXPERIMENTAL APPROACH

DA-8159 (30 mg kg(-1)) and metformin (100 mg kg(-1)), both separately and together, were administered to rats either intravenously or orally. The V (max), K (m), CL(int), apparent inhibition constants (K (i)), [I]/K (i) and concentrations of each drug in the liver and intestine were then measured.

KEY RESULTS

After i.v. administration of both drugs simultaneously, the AUC of DA-8159 and metformin was significantly greater (21.2 and 33.9% increase for DA-8159 and metformin, respectively) than that of each drug alone. After p.o. administration of the drugs, the AUC of metformin was also significantly greater (20.7% increase) in the presence of DA-8159 than in its absence. However, the AUC of DA-8159 was similar in the absence and presence of metformin.

CONCLUSIONS AND IMPLICATIONS

The significantly greater AUC of metformin and DA-8159 after i.v. administration of both drugs and of metformin after p.o. administration of both drugs is probably due to competitive inhibition for the metabolism of these drugs via hepatic CYP3A1/2. However, the similar AUCs of DA-8159 in the absence and presence of metformin, after p.o. administration, indicates that the dose of metformin used was insufficient to inhibit the hepatic and intestinal metabolism of DA-8159.

Steatohepatitis due to antiretroviral therapy

Jamaica has recorded the largest increase in the rate of HIV/AIDS infection in the English-speaking Caribbean since 1985. Treatment has significantly improved recently with approximately 50% availability of antiretrovirals (ARVs) to patients. The incidence of drug induced hepatotoxicity is not well known for most ARV drugs and few studies have assessed adverse drug effects in clinical practice. A patient with HIV on highly active antiretroviral therapy (HAART) presented with a one year history of progressive abdominal distension. Abdominal examination revealed a 17 cm, smooth, non-tender liver with a rounded edge; 12 cm of which was below the right costal margin. Liver enzymes were grossly abnormal. The liver biopsy revealed parenchymal distortion by fibrosis with macrovesicular fatty change and Mallory's hyaline in keeping with steatohepatitis. Follow-up studies after discontinuation of stavudine revealed that the liver enzymes improved within four months. Physicians should be mindful of the hepatotoxic potential of ARVs and monitor liver enzymes in HIV-infected patients on therapy.

Molecular and functional expression of anion exchangers in cultured normal human nasal epithelial cells

Aims

Anions have an important role in the regulation of airway surface liquid (ASL) volume, viscosity and pH. However, functional localization and regulation of anion exchangers (AEs) have not been clearly described. The aim of this study was to investigate the regulation of AE mRNA expression level in accordance with mucociliary differentiation and the functional expression of AEs cultured normal human nasal epithelial (NHNE) cells.

Methods

Nasal mucosal specimens from three patients are obtained and serially cultured cells are subjected to morphological examinations, RT-PCR, Western blot analysis and immunocytochemistry. AE activity is assessed by pHi measurements.

Results

Expression of ciliated cells on the apical membrane and expression of MUC5AC, a marker of mucous differentiation, increased with time. AE2 and SLC26A4 mRNA expression decreased as mucociliary differentiation progressed, and AE4, SLC26A7 and SLC26A8 mRNA expression increased on the 14th and 28th day after confluence. Accordingly, AE4 protein expression also progressively increased. AE activity in 100 mm K⁺ buffer solutions was nearly twofold higher than that in 5 mm K⁺ buffer solutions. Moreover, only luminal AE activity increased about fourfold over the control in the presence of 5 μm forskolin. In the presence of 100 μm adenosine-5′-triphosphate (ATP) which evokes intracellular calcium signalling through activation of purinergic receptors, only luminal AE activity was again significantly increased. On the other hand, 500 μm 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS), an inhibitor of most SLC4 and SLC26AE isoforms, nearly abolished AE activity in both luminal and basolateral membranes. We found that AE activity was affected by intracellular cAMP and calcium signalling in the luminal membrane and was DIDS-sensitive in both membranes of cultured NHNE cells.

Conclusion

Our findings through molecular and functional studies using cultured NHNE cells suggest that AEs may have an important role in the regulation of ASL.

Influence of OATP1B1 genotype on the pharmacokinetics of rosuvastatin in Koreans

This study was carried out to determine whether polymorphisms of organic anion-transporting polypeptide 1B1 (OATP1B1) have an effect on rosuvastatin pharmacokinetics in Koreans. Among 200 subjects genotyped for OATP1B1 c.388A>G, and c.521T>C, 30 subjects were selected for the rosuvastatin pharmacokinetic study. The area under the concentration-time curve for 0 to infinity (AUC(0-infinity)) of rosuvastatin for group 1 (*1a/*1a, *1a/*1b, *1b/*1b), group 2 (*1a/*15, *1b/*15), and group 3 (*15/*15) were 111+/-49.3, 126+/-45.2, and 191+/-31.0 ng h/ml, respectively, with significant differences among the three groups (P=0.0429) and between *15/*15 and the other groups (P=0.0181). The maximum plasma concentration (Cmax) also showed a significant difference between *15/*15 and the other groups (P=0.0181). There were no significant differences in rosuvastatin-lactone pharmacokinetics among the three groups. The pharmacokinetic exposure of rosuvastatin was higher in the OATP1B1*15/*15 subjects than the others, suggesting a potential association between the OATP1B1 genetic polymorphisms and altered rosuvastatin pharmacokinetics in Korean populations.

Pharmacokinetic and pharmacodynamic consequences of inhibition of terazosin metabolism via CYP3A1 and/or 3A2 by DA-8159, an erectogenic, in rats

BACKGROUND AND PURPOSE

Recently, orthostatic hypotension was observed in patients with benign prostatic hyperplasia who are taking vardenafil (a PDE 5 inhibitor) and terazosin (a long acting alpha blocker). Therefore, this study was performed with DA-8159 (a long acting PDE 5 inhibitor) and terazosin in rats to find whether or not pharmacokinetic and pharmacodynamic interactions between the two drugs were observed.

EXPERIMENTAL APPROACH

Pharmacokinetic and pharmacodynamic (changes in blood pressure) interactions between DA-8159 and terazosin were evaluated after simultaneous i.v. and p.o. administration of DA-8159 (30 mg kg(-1)) and terazosin (5 mg kg(-1)) to male Sprague-Dawley rats.

KEY RESULTS

After simultaneous i.v. and p.o. administration of terazosin and DA-8159, the total area under the plasma concentration-time curve from time zero to time infinity (AUC) of terazosin became significantly greater (57.4 and 75.4% increase for i.v. and p.o. administration, respectively) than those of without DA-8159. The blood pressure dropping effect was considerable after simultaneous p.o. administration of DA-8159 and terazosin compared with each drug alone.

CONCLUSIONS AND IMPLICATIONS

The significantly greater AUC of terazosin after both simultaneous i.v. and p.o. administration of both drugs could be due to the hepatic (both i.v. and p.o.) and intestinal (p.o.) inhibition of the metabolism of terazosin via CYP3A1 and/or 3A2 by DA-8159, since both DA-8159 and terazosin are metabolized via CYP3A1 and/or 3A2 in rats. The blood pressure lowering effect after simultaneous p.o. administration of both drugs could be due to significant increase in plasma concentrations of terazosin.

Effects of enzyme inducers and inhibitors on the pharmacokinetics of metformin in rats: involvement of CYP2C11, 2D1 and 3A1/2 for the metabolism of metformin

BACKGROUND AND PURPOSE

The types of hepatic microsomal cytochrome P450 (CYP) isozymes responsible for the metabolism of metformin in humans and rats have not been published to date. Therefore, a series of experiments using various inducers and inhibitors of CYP isozymes was conducted to find out what types of CYP isozymes are involved in the metabolism of metformin in rats.

EXPERIMENTAL APPROACH

Metformin at a dose of 100 mg kg(-1) was administered intravenously to rats. The rats were pretreated with CYP inducers such as 3-methylcholanthrene, orphenadrine, isoniazid, and dexamethasone (major inducers of CYP1A1/2, 2B1/2, 2E1, and 3A1/2, respectively, in rats), or CYP inhibitors such as SKF-525 (a non-specific inhibitor of CYP isozymes), and sulfaphenazole, quinine, and troleandomycin (major inhibitors of CYP2C11, 2D1, and 3A1/2, respectively, in rats). The time-averaged non-renal clearance (CLNR) of metformin was compared with that of controls.

KEY RESULTS

In rats pretreated with dexamethasone, the CLNR was significantly faster (57% increase) than for the controls. In rats pretreated with SKF-525-A, sulfaphenazole, quinine, and troleandomycin, the CLNR was significantly slower (24.3, 62.9, 77.6, and 78.7% decrease, respectively) than for the controls. However, the CLNR values did not significantly different in the rats pretreated with 3-methylencholanthrene, orphenadrine, and isoniazid compared with the controls.

CONCLUSIONS AND IMPLICATIONS

Our data suggest that metformin was metabolized mainly via CYP2C11, 2D1, and 3A1/2 in rats. This result could contribute to understanding of the possible changes in metformin pharmacokinetics in disease models where CYP2C11 and/or 3A1/2 are altered.

RNA polymerase I-mediated protein-coding gene expression in Trypanosoma brucei

Protein-coding genes are transcribed by RNA polymerise (pol) II in all eukaryotes analyzed to date, with the exception of the protozoan Trypanosoma brucei, where pol I can mediate expression of chloramphenicol acetyl transferase (CAT) and neomycin phosphotransferase (neo) reporter genes. The addition of the capped 39-nucleotide (nt) mini-exon to the pre-messenger RNA (mRNA) by trans-splicing in T. brucei has presumably led to the uncoupling of the requirement for production of mRNA by pol II. Here Hui-min Chung, Mary G-S. Lee and Lex Van der Ploeg review the evidence that supports the notion that pol I also transcribes a subset of naturally occurring protein-coding genes in T. brucei.

Antibiotic sensitivity of Helicobacter pylori in Jamaica

Helicobacter pylori infection is one of the commonest chronic infections worldwide. Eradication regimes usually contain two antibiotics, however resistance is increasing and this decreases treatment success. This study reports on the sensitivity and resistance of H pylori to several antibiotics in patients undergoing upper gastrointestinal endoscopy in Jamaica. The rapid urease test (CLO) was positive in 128 (38%) of 336 patients. Fifty patients (39%; 50/128) with positive CLO tests had positive cultures for H pylori. Two-thirds (32/48) of islolates were sensitive to metronidazole and one-third (16/48) were resistant. Ninety-seven per cent of isolates (31/32) were sensitive to erythromycin. The sensitivity for clarithromycin was 92% (11/12) with one isolate (8%) resistant. All strains of H pylori (48/48) were sensitive to ampicillin and amoxicillin - clavulanate. Metronidazole resistance is present in one-third of H pylori isolates and resistance to macrolides is relatively low in Jamaican patients. It is important to monitor antibiotic resistance in order to provide clinicians with data on the most appropriate and cost effective eradication regimes for H pylori.

Glutathione depletion is a major determinant of inhaled naphthalene respiratory toxicity and naphthalene metabolism in mice

Naphthalene (NA) is metabolized to highly reactive intermediates that are primarily detoxified by conjugation to glutathione (GSH). Intraperitoneal administration of naphthalene causes substantial loss of both hepatic and respiratory GSH, yet only respiratory tissues are injured in mice. The liver supplies GSH to other organs via the circulation, making it unclear whether respiratory GSH losses reflect in situ respiratory depletion or decreased hepatic supply. To address this concern, mice were exposed to naphthalene by inhalation (1.5-15 ppm; 2-4 h), thereby bypassing first-pass hepatic involvement. GSH levels and histopathology were monitored during the first 24 h after exposure. Half of the mice were given the GSH depletor diethylmaleate (DEM) 1 hour before naphthalene exposure. Lung and nasal GSH levels rapidly decreased (50-90%) in mice exposed to 15 ppm naphthalene, with cell necrosis throughout the respiratory tract becoming evident several hours later. Conversely, 1.5 ppm naphthalene caused moderate GSH loss and only injured the nasal olfactory epithelium. Neither naphthalene concentration depleted hepatic GSH. Animals pretreated with DEM showed significant GSH loss and injury in nasal and intrapulmonary airway epithelium at both naphthalene concentrations. DEM treatment, perhaps by causing significant GSH loss, decreased water-soluble naphthalene metabolite formation by 48% yet increased NA-protein adducts 193%. We conclude that (1) GSH depletion occurs in airways independent of hepatic function; (2) sufficient GSH is not supplied by the liver to maintain respiratory GSH pools, or to prevent injury from inhaled naphthalene; and (3) GSH loss precedes injury and increases protein adduct formation.