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.

Pharmacokinetics of mirodenafil, a new erectogenic, and its metabolite, SK3541, in rats: involvement of CYP1A1/2, 2B1/2, 2D subfamily, and 3A1/2 for the metabolism of both mirodenafil and SK3541

PURPOSE

This study was performed to find which types of hepatic CYP isoforms are responsible for the metabolism of mirodenafil (a new erectogenic) and one of its metabolite, SK3541, using various hepatic CYP inducers and inhibitors in rats.

METHODS

Mirodenafil at a dose of 20 mg/kg was administered intravenously to control rats and rats pretreated with various CYP inducers and inhibitors. The disappearance of SK3541 was also measured in vitro hepatic microsomes of rats with and without CYP inducer and inhibitors.

RESULTS

Compared to controls, in rats pretreated with 3-methylcholanthrene, orphenadrine, and dexamethasone (main inducers of CYP1A1/2, 2B1/2, and 3A1/2, respectively), the non-renal clearances (CLNRs) of mirodenafil were significantly faster (by 39.4%, 59.3%, and 63.9%, respectively). However, compared to controls, in rats pretreated with quinine and troleandomycin (main inhibitors of CYP2D subfamily and 3A1/2, respectively), the CLNRs of mirodenafil were significantly slower (by 36.1% and 33.2%, respectively). In rat hepatic microsomes spiked with furafylline, quinine, and troleandomycin (main inhibitors of CYP1A2, 2D subfamily, and 3A1/2, respectively), the intrinsic clearances (CLints) for the disappearance of SK3541 were significantly slower (by 18.4%, 35.3%, and 51.5%, respectively) than controls. Also in rat hepatic microsomes pretreated with orphenadrine (a main inducer of CYP2B1/2), the CLint for the disappearance of SK3541 was significantly faster (by 55.5%) than controls.

CONCLUSIONS

The above data suggest that hepatic CYP1A1/2, 2B1/2, 2D subfamily, and 3A1/2 are involved in the metabolism of both mirodenafil and SK3541 in rats.

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.

Effect of enzyme inducers and inhibitors on the pharmacokinetics of oltipraz in rats

A series of in-vitro and in-vivo experiments, using various inducers and inhibitors of hepatic microsomal cytochrome P450 (CYP) isozymes, was conducted to study oltipraz pharmacokinetics in rats. In in-vivo studies, oltipraz at a dose of 10 mg kg−1 was administered intravenously to rats. In rats pretreated with SKF 525-A (a nonspecific CYP isozyme inhibitor in rats; n = 9), the time-averaged total body clearance (CL) of oltipraz was significantly slower (56.6% decrease) than that in untreated rats (n = 9). This indicated that oltipraz is metabolized via CYP isozymes in rats. Hence, various enzyme inducers or inhibitors were used in in-vitro and in-vivo studies in rats. In rats pretreated with 3-methylcholanthrene (n = 9 and 8 for untreated and treated groups, respectively), phenobarbital (n = 7 and 10 for untreated and treated groups, respectively) or dexamethasone (n = 7 and 12 for untreated and treated groups, respectively) (main inducers of CYP1A1/2, 2B1/2 and 3A1/2 in rats, respectively), the CL values were significantly faster (38.4, 94.4 and 33.6% increase, respectively). In rats pretreated with sulfaphenazole (n = 8 and 9 for untreated and treated groups, respectively), quinine (n = 7 and 9 for untreated and treated groups, respectively) or troleandomycin (n = 8 and 9 for untreated and treated groups, respectively) (main inhibitors of CYP2C11, 2D1 and 3A1/2 in rats, respectively), the CL values were significantly slower (31.0, 27.6 and 36.3% decrease, respectively). The in-vivo results with various enzyme inhibitors correlated well with the in-vitro intrinsic clearance for disappearance of oltipraz (CLint) (n = 5, each). The above data suggested that oltipraz could be metabolized in male rats mainly via CYP1A1/2, 2B1/2, 2C11, 3A1/2 and 2D1.

Effects of the rate and composition of fluid replacement on the pharmacokinetics and pharmacodynamics of intravenous torasemide

The effects of differences in the rate and composition of intravenous fluid replacement for urine loss on the pharmacokinetics and pharmacodynamics of torasemide were evaluated in rabbits. Each rabbit received 2-h constant intravenous infusion of 1 mg kg−1 torasemide with 0% replacement (treatment 1, n = 6), 50% replacement (treatment 2, n = 9), 100% replacement with lactated Ringer's solution (treatment 3, n = 8), and 100% replacement with 5% dextrose in water (treatment 4, n = 6). Total body (4.53, 5.72, 10.0 and 4.45 mL min−1 kg−1 for treatments 1–4, respectively) and renal clearance (1.44, 1.87, 6.78 and 1.72 mL min−1 kg−1) of torasemide, and total amount of unchanged torasemide excreted in 8-h urine (Ae 0–8 h: 694, 780, 1310 and 1040 μg) in treatment 3 were considerably faster and greater compared with treatments 1, 2 and 4. Although the difference in Ae 0–8 h between treatments 1 and 3 was only 88.8%, the diuretic and/or natriuretic effects of torasemide were markedly different among the four treatments. For example, the mean 8-h urine output was 101, 185, 808 and 589 mL for treatments 1–4, respectively, and the corresponding values for sodium excretion were 10.1, 20.6, 89.2 and 29.9 mmol, and for chloride excretion were 14.5, 27.9, 94.0 and 37.2 mmol. Although full fluid replacement was used in both treatments 3 and 4, the 8-h diuretic, natriuretic and chloruretic effects in treatment 3 were significantly greater compared with treatment 4, indicating the importance of the composition of fluid replacement. Both treatments 1 and 4 received no sodium replacement, however, the 8-h diuretic, natriuretic and chloruretic effects were significantly greater in treatment 4 compared with treatment 1, indicating the importance of rate of fluid replacement for the diuretic effects. Therefore, the 8-h diuretic, natriuretic and chloruretic effects were significantly greater in treatment 3 compared with treatments 1, 2 and 4, indicating the importance of full fluid and electrolyte replacement. Some implications for the bioequivalence evaluation of dosage forms of torasemide are discussed.

Pharmacokinetic interaction between oltipraz and dimethyl-4,4‘-dimethoxy-5,6,5′,6’-dimethylene dioxybiphenyl-2,2′-dicarboxylate (DDB) after single intravenous and oral administration to rats

The aim of this study was to report the pharmacokinetic interaction between oltipraz (50 mg kg−1) and dimethyl-4,4′-dimethoxy-5,6,5′,6′-dimethylene dioxybiphenyl-2,2′-dicarboxylate (DDB, 10 mg kg−1) after single intravenous and oral administration to rats. After intravenous administration of oltipraz plus DDB, the area under the plasma concentration–time curve from time zero to time infinity (AUC) of oltipraz was significantly greater (1440 vs 1740 μg min mL−1) than that after oltipraz alone. This was not due to slower clearances of oltipraz after oltipraz plus DDB since the total body, renal and nonrenal clearances were comparable between the two groups of rats. It could be due to a decrease in tissue binding of oltipraz by DDB. The apparent volume of distribution at steady state (Vdss) of DDB was significantly smaller (7060 vs 4650 mL kg−1) than after oltipraz alone. After oral administration of oltipraz plus DDB, the AUC of olitpraz was also significantly greater (479 vs 583 μg min mL−1) than that after oltipraz alone. This was not due to increased absorption of oltipraz from the rat gastrointestinal tract after oltipraz plus DDB but again could be due to a decrease in Vdss of oltipraz by DDB. However, after both intravenous and oral administration, the pharmacokinetic parameters of DDB were comparable between DDB alone and DDB plus oltipraz, indicating that oltipraz did not greatly affect the pharmacokinetics of DDB in rats.

Pharmacokinetic interaction between 5-[2-propyloxy-5-(1-methyl-2-pyrollidinylethylamidosulfonyl)phenyl]-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo (4,3-d) pyrimidine-7-one (DA-8159) and nitroglycerin in rats

The pharmacokinetic interaction between 5-[2-propyloxy-5-(1-methyl-2-pyrollidinylethylamidosulfonyl)phenyl]-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo (4,3-d)pyrimidine-7-one (DA-8159), a new erectogenic, and nitroglycerin has been evaluated in rats. Male Sprague-Dawley rats received DA-8159 (30 mgkg−1) as a single intravenous or oral dose with the simultaneous single intravenous administration of nitroglycerin (2.5 mgkg−1). After simultaneous intravenous administration, the total area under the plasma concentration-time curve from time zero to time infinity (AUCinf) of DA-8159 (746 vs 457 μg min mL−1) was found to be significantly greater than with DA-8159 alone. Also, after simultaneous intravenous administration total body clearance (CL) (40.2 vs 65.6 mL min−1 kg−1), renal clearance (CLR) (1.65 vs 5.11 mL min−1 kg−1), and nonrenal clearance (CLNR) (38.3 vs 60.2 mL min−1 kg−1) of DA-8159 were significantly slower compared with DA-8159 alone. The slower CLNR of DA-8159 could have been due to the inhibition of the metabolism of DA-8159 by nitroglycerin, since DA-8159 is metabolized via CYP3A1/2 in rats and nitroglycerin inhibits CYP3A1/2 in rats. The slower CLR of DA-8159 could have been due to the urine flow rate-dependent CLR of DA-8159 in rats. After the simultaneous intravenous administration of nitroglycerin and DA-8159, the AUCinf of nitroglycerin was significantly smaller (635 vs 960 μg min mL−1), which could have been due to the cardiac output-dependent CL of nitroglycerin. However, after the oral administration of DA-8159, the pharmacokinetic parameters of DA-8159 with and without the intravenous administration of nitroglycerin became comparable. This was not due to the decrease in nitroglycerin's gastrointestinal absorption of DA-8159, but could have been due to changes in nitroglycerin's intestinal first-pass effect of DA-8159. Human studies are required to determine the administration time of DA-8159 when nitroglycerin is concomitantly taken.

Effects of protein-calorie malnutrition on the pharmacokinetics of DA-7867, a new oxazolidinone, in rats

The pharmacokinetic parameters of DA-7867, a new oxazolidinone, were compared after intravenous and oral administration at a dose of 10mg kg−1 to control rats and rats with protein-calorie malnutrition (rats with PCM). After intravenous administration of 10mg kg−1 DA-7867 to rats, metabolism of the drug was not considerable and after 14 days approximately 85.0% of the dose was recovered as unchanged drug from urine and faeces. After intravenous administration to rats with PCM, the area under the plasma concentration-time curve from time zero to time infinity (AUC) was significantly smaller (10800 vs 6990μg min mL−1) compared with control rats. This may have been due to significantly faster total body clearance (CL, 0.930 vs 1.44mL min−1 kg−1). The faster CL in PCM rats could have been due to significantly faster non-renal clearance (0.842 vs 1.39mL min−1 kg−1 due to significantly greater gastrointestinal (including biliary) excretion; the amount of unchanged DA-7867 recovered from the entire gastrointestinal tract at 24h was significantly greater (1.19 vs 4.28% of intravenous dose)) because the renal clearance was significantly slower in PCM rats (0.0874 vs 0.0553mL min−1 kg−1). After oral administration to PCM rats, the AUC was significantly smaller compared with control rats (7900 vs 4310μgmin mL−1). This could have been due to a decrease in absorption from the gastrointestinal tract.

Efficacy of sauchinone as a novel AMPK-activating lignan for preventing iron-induced oxidative stress and liver injury

Iron-overload disorders cause hepatocyte injury and inflammation by oxidative stress, possibly leading to liver fibrosis and hepatocellular carcinoma. This study investigated the efficacy of sauchinone, a bioactive lignan, in preventing iron-induced liver injury and explored the mechanism of sauchinone's activity. To create iron overload, mice were injected with phenylhydrazine, and the effects on hepatic iron and histopathology were assessed. Phenylhydrazine treatment promoted liver iron accumulation and ferritin expression, causing hepatocyte death and increased plasma arachidonic acid (AA). Sauchinone attenuated liver injury (EC(50)=10 mg/kg) and activated AMPK in mice. Treatment of hepatocytes with iron and AA simulated iron overload conditions: iron + AA synergistically amplified cytotoxicity, increasing H(2)O(2) and the mitochondrial permeability transition. Sauchinone protected hepatocytes from iron + AA-induced cytotoxicity, preventing the induction of mitochondrial dysfunction and apoptosis (EC(50)=1 microM), similar to the result using metformin. Sauchinone treatment activated LKB1, which led to AMPK activation: these events contributed to cell survival. Evidence of cytoprotection by LKB1 and AMPK activation was revealed in the reversal of sauchinone's restoration of the mitochondrial membrane potential by either dominant negative mutant AMPKalpha or chemical inhibitor. In conclusion, sauchinone protects the liver from toxicity induced by iron accumulation, and sauchinone's effects may be mediated by LKB1-dependent AMPK activation.

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.