Anti-inflammatory and diuretic effects of the diterpene ent-dihydrotucumanoic acid.

Gymnosperma glutinosum (Spreng) Less (Asteraceae) is a shrub used in traditional medicine for the treatment of inflammatory and renal diseases. The ent-dihydrotucumanoic acid (DTA) is a diterpene obtained from G. glutinosum. This study evaluated the antioxidant, genotoxic, and diuretic properties of DTA, as well as its in vitro and in vivo anti-inflammatory actions. The antioxidant actions of DTA were assessed with the 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), ferric reducing antioxidant power (FRAP), and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) assays, the genotoxic action was assessed with the comet assay, and the diuretic effects of DTA were assessed using metabolic cages. The anti-inflammatory actions were evaluated using primary murine peritoneal macrophages stimulated with LPS and the λ-carrageenan-induced hind paw edema test. DTA lacked antioxidant (IC50 > 25,000 µg/mL) activity in the ABTS, FRAP, and DPPH assays. DTA at 500-1,000 µg/mL showed moderate genotoxicity. In LPS-stimulated macrophages, DTA showed IC50 values of 74.85 µg/mL (TNF-α) and 58.12 µg/mL (NO), whereas the maximum inhibition of IL-6 (24%) and IL-1ß (36%) was recorded at 200 µg/mL. DTA induced in vivo anti-inflammatory effects with ED50 = 124.3 mg/kg. The in vitro anti-inflammatory activity of DTA seems to be associated with the decrease in the release of TNF-α and NO. DTA promoted the excretion of urine (ED50 = 86.9 mg/kg), Na+ (ED50 = 66.7 mg/kg), and K+ (ED50 = 8.6 mg/kg). The coadministration of DTA with L-NAME decreased the urinary excretion shown by DTA alone. Therefore, the diuretic activity is probably associated with the participation of nitric oxide synthase. In conclusion, DTA exerted anti-inflammatory and diuretic effects, but lacked antioxidant effects.

Uso inapropiado de diuréticos: Algunas características no tan conocidas / Diuretic misuse: Some not so well known characteristics

Entre las situaciones asociadas al uso inapropiado de diuréticos se encuentran los intentos por descencer rápidamente de peso, comunes en los desordenes de la alimentación, y los intentos por enmascarar el consumo de otras sustancias, en el caso de las competencias deportivas. El uso sin indicación ni supervisión médica de estos fármacos genera un desbalance electrolítico, que puede manifestarse con hiponatremia, hipocalemia, hipocalcemia e hipomagnesemia, hipercalemia, entre otras alteraciones. El objetivo de este trabajo fue investigar las caracteríscas del uso inapropiado de diuréticos a partir de la casuística del CENATOXA. Se realizó un estudio descriptivo restrospectivo sobre los análisis ingresados al CENATOXA con solicitud de investigación cualitativa de diuréticos en orina, entre los años 2002 y 2016. En dicho período ingresaron al CENATOXA 138 casos, de los cuales el 56 % resultó positivo para algún diurético. Del total de casos con resultado positivo, el 93,5 % fueron mujeres entre 25 y 55 años de edad y predominó la etiología intencional. Los diuréticos mayoritariamente encontrados fueron hidroclorotiazida y furosemida. El perfil de diuréticos hasta el año 2008 (hidroclorotiazida = 68% de los casos positivos) se diferenció del hallado entre 2009 y 2016 (furosemida + hidroclorotiazida = 60% de los casos positivos). Se observó recurrencia en el uso inapropiado en el 8% de los casos. El uso simultáneo de más de un diurético y la recurrencia son factores que pueden contribuir a la aparición de toxicidad. Estos resultados sugieren que el uso inapropiado de diuréticos es una situación que debería ser ob­servada más atentamente para establecer mejor su alcance y sus riesgos.

Among the situations associated with diuretics misuse are the attempts to lose weight fast, frequently observed in eating disorders, and the attempts to mask the consumption of other substances, in the case of sports competitions. The use of these drugs with no medical indication or supervision generates an electrolyte imbalance, leading to hyponatremia, hypokalemia, hypocalcemia and hypomagnesemia, hyperkalemia, among other alterations. The objective of this work was to investigate the characteristics of diuretics misuse from the CENATOXA database, where the qualitative investigation of diuretics in urine is per­formed. A descriptive retrospective study was conducted on the cases admitted to the CENATOXA with a request for qualitative diuretic investigation, between 2002 and 2016. During this period, 138 urine samples were received at the CENATOXA and 56% were positive for at least one diuretic. Of all cases with positive results, 93.5% were women between 25 and 55 years of age, and intentional etiology predominated. The most detected diuretics were hydrochlorothiazide and furosemide. The diuretic misuse pattern detected up to 2008 (hydrochlorothiazide = 68% of positive cases) differed from that detected between 2009 and 2016 (furosemide + hydrochlorothiazide = 60% of positive cases). Recurrence in misuse was observed in 8% of the cases. The simul­taneous misuse of more than one diuretic and the recurrence are factors that can contribute to the onset of toxicity. These results suggest that diuretic misuse is a situation that should be observed more closely to better assess its consequences and its risks.

Protection of Hair Cells from Ototoxic Drug-Induced Hearing Loss.

Hair cells are specialized sensory epithelia cells that receive mechanical sound waves and convert them into neural signals for hearing, and these cells can be killed or damaged by ototoxic drugs, including many aminoglycoside antibiotics, platinum-based anticancer agents, and loop diuretics, leading to drug-induced hearing loss. Studies of therapeutic approaches to drug-induced hearing loss have been hampered by the limited understanding of the biological mechanisms that protect and regenerate hair cells. This review briefly discusses some of the most common ototoxic drugs and describes recent research concerning the mechanisms of ototoxic drug-induced hearing loss. It also highlights current developments in potential therapies and explores current clinical treatments for patients with hearing impairments.

Colectomy induces an aldosterone-mediated increase in jejunal glucose uptake in rats.

AIMS: The main function of the colon is water and electrolyte absorption. Total colectomy eliminates this colonic function and may alter the absorptive capacity of the small intestine for nutrients. This study examines the effect of total colectomy on jejunal glucose absorption and investigates the potential role of aldosterone in mediating the alterations in glucose uptake post-colectomy using the aldosterone antagonist spironolactone. MAIN METHODS: Total colectomy with ileo-rectal anastomosis was performed on anesthetized rats. Sham rats were identically handled without colon resection. Two days post-surgery, groups of colectomized rats were injected with either a daily subcutaneous dose of spironolactone or sesame oil for 12days. Body weight changes and food and water intake were measured in all experimental groups. Glucose absorption was measured by in-vivo single pass perfusion in the rat jejunum of control, sham, colectomized, colectomized with spironolactone, and colectomized with sesame oil treatment. Na/K ATPase, SGK1, SGLT1 and GLUT2 expressions were determined in jejunal mucosa in control, colectomized and colectomized/spironolactone injected rats by Western blot analysis. Histological assessment was performed on jejunal sections in control and colectomized groups. KEY FINDINGS: Glucose absorption significantly increased in colectomized rats with an observed increase in Na/K ATPase and SGK1 expression. No significant expression change in SGLT1 and GLUT2 was detected in the jejunum in colectomized rats. Spironolactone, however, significantly decreased the glucose uptake post-colectomy and normalized Na/K ATPase and SGK1 expression. SIGNIFICANCE: Our results suggest that jejunal glucose uptake increases post-colectomy as a possible consequence of an aldosterone-mediated function.

The combined effect of furosemide and propranolol on GSH homeostasis in ACHN renal cells.

OBJECTIVES: Propranolol, a beta-adrenergic blocker, is used in the treatment of a large number of cardiovascular diseases such as hypertension and arrhythmias. Propranolol, in combination with furosemide, is used to treat hypertensive disorders although their side effect profile is not very obvious. In present study, the effects of the drugs furosemide and propranolol were in corporately investigated both on glutathione homeostasis and their antioxidant effect on ACHN cells. METHODS: The cytoxicities and antioxidant effects of these two clinically important drugs on human kidney cell lines were evaluated using MTT following by the determination of glutathione reductase (GR) and glutathione peroxidase (GPx) activities and measuring the level of reduced glutathione (GSH). RESULTS: Propranolol induced a significant cytotoxic effect at 100 µM, while furosemide was cytotoxic at doses of 250 and 1000 µg/ml. A slight increase in GPx and GR activities and GSH level was observed with propranolol and furosemide treatment alone, while the two drugs together caused a significant increase in GPx and GR activities (35% and 42%, respectively) and GSH content (35%) in ACHN cell lysates (p < 0.05). CONCLUSIONS: Our results demonstrate that although high doses of furosemide and propranolol are cytotoxic, co-administration of low doses may improve the antioxidant defense in patients undergoing treatment with these two important drugs.

Efecto diurético agudo de los extractos etanólico y acuoso de Ceratopteris pteridoides (Hook) en ratas normales / Acute diuretic effect of ethanolic and aqueous extracts of Ceratopteris pteridoides (Hook) in normal rats

Introducción. Ceratopteris pteridoides es un helecho semiacuático de la familia Parkeriacea, ampliamente utilizado en la medicina popular colombiana como diurético y colelitiásico, sobre el cual no existen reportes científicos que avalen su uso popular como diurético. Objetivo. Evaluar el efecto diurético agudo en dosis única y dosis repetidas a corto plazo, de los extractos etanólico y acuoso de C. pteridoides en un modelo in vivo . Materiales y métodos. El extracto etanólico total fue obtenido por maceración de la planta entera de C. pteridoides con etanol y el extracto acuoso fue obtenido por decocción a 60 °C por 15 minutos. Ambos extractos se sometieron a análisis fitoquímico preliminar y estudio histológico posterior a la administración de los extractos durante ocho días consecutivos (1.000 mg/kg). El efecto diurético se evaluó en ratas Wistar, tratadas con los extractos (500 mg/kg), en forma aguda y en dosis repetidas a corto plazo, cuantificando la eliminación de agua y la excreción renal de sodio y potasio por espectrofotometría de absorción atómica y, de cloruros, por titulación mercurimétrica. Resultados. En el modelo agudo, ambos extractos mostraron un significativo efecto diurético y de excreción renal de sodio y potasio en comparación con el control, mientras que con la administración en dosis repetidas a corto plazo mostraron efecto diurético sin eliminación de electrolitos. El estudio histopatológico no sugirió efectos tóxicos hepáticos o renales. Conclusión. Los resultados demuestran la actividad diurética de C. pteridoides y sustentan el uso popular dado a esta planta como diurético en la costa norte colombiana. Se requieren estudios posteriores que permitan aislar e identificar los compuestos responsables de la actividad y los mecanismos de acción involucrados.

Introduction. Ceratopteris pteridoides is a semiaquatic fern of the Parkeriacea family, widely used in the Colombian folk medicine as a diuretic and cholelithiasic, of which there are no scientific reports that validate its popular use. Objective. To evaluate the acute and short-term repeated-dose diuretic effect of the ethanolic and aqueous extracts of C. pteridoides in an in vivo model. Materials and methods. The total ethanolic extract was obtained by maceration of the whole plant of C. pteridoides with ethanol and the aqueous extract by decoction at 60°C for 15 minutes. Both extracts were evaluated in preliminary phytochemical analysis and histological studies after the administration of the extracts for 8 consecutive days (1000 mg/Kg). The diuretic effect was evaluated using Wistar rats treated with the extracts (500 mg/Kg), using an acute and a short-term repeated-dose model, and quantifying water elimination, sodium and potassium excretion by atomic absorption spectrophotometry, and chloride excretion by mercurimetric titration. Results. In the acute model both extracts showed significant diuretic, natriuretic, and kaliuretic effect compared to the control group. Whereas, a short-term repeated-dose administration showed a diuretic effect without elimination of electrolytes. The histopathologic study did not suggest a toxic effect in liver or kidney. Conclusion. The results represent evidence of the diuretic activity of C. pteridoides and give support the popular use given to this plant in the north coast of Colombia. Further studies are required to isolate and identify the compounds responsible for the activity and the mechanism of action involved.

Nonclinical safety profile of tolvaptan.

PURPOSE: In the present study, the nonclinical safety profile of tolvaptan was evaluated. METHODS: A series of safety pharmacology and toxicology studies were performed in vitro and in mice, rats, dogs, rabbits and guinea pigs. RESULTS: In safety pharmacological studies, tolvaptan had no adverse effects on the central nervous, somatic nervous, autonomic nervous, smooth muscle, respiratory and cardiovascular, or digestive systems. In general toxicity studies, a single dose of tolvaptan up to 2,000 mg/kg was not lethal in rats and dogs. Tolvaptan did not cause any target organ toxicity in rats after treatment for 26 weeks or in dogs after treatment for 52 weeks at oral doses of up to 1,000 mg/kg/day. The toxicities observed in the present studies were generally attributable to the exaggerated pharmacological action of tolvaptan. In reproductive and developmental toxicity studies in rats, fertility was not affected. Suppressed viability or growth observed in the prenatal and postnatal progeny occurred at the maternally toxic dose of 1,000 mg/kg/day. In rabbits, tolvaptan showed teratogenicity at 1,000 mg/kg/day, a dose that was maternally toxic causing abortion. Tolvaptan was not genotoxic or carcinogenic, and did not induce phototoxicity, antigenicity or immunotoxicity. CONCLUSION: Nonclinical toxicity that precludes the safe administration of tolvaptan to humans was not observed. However, appropriate cautions should be taken in women of childbearing potential.

Effects of NasoPore packing in the middle ear cavity of the guinea pig.

OBJECTIVE: To evaluate the effects of NasoPore after packing of the middle ear in guinea pigs. STUDY DESIGN: A randomized, prospective, controlled animal study. SETTING: University laboratory. SUBJECTS AND METHODS: Forty-one guinea pigs were divided into 3 groups. In group 1(n=12), the middle ears of animals were unilaterally implanted with NasoPore, leaving the contralateral middle ears packed with absorbable gelatin sponge soaked in a solution containing kanamycin and furosemide as an ototoxicity-positive control; group 2 (n = 17) underwent the same experimental protocol as group 1, except the gelatin sponge was unsoaked; in group 3 (n = 12), NasoPore was inserted unilaterally and no packing material was placed into the contralateral ear. Auditory brainstem responses (ABRs) were performed preoperatively and 3 months after the procedure. The surface preparation and scanning electron microscopy (SEM) were assessed 3 months postoperatively, whereas pathology of middle ear was analyzed in 5 samples of group 2. RESULTS: ABR thresholds of the contralateral ear significantly increased in group 1 and were slightly shifted in group 2 compared with the NasoPore-packed and nonpacked ears 3 months postoperatively. The NasoPore-packed middle ears were found to have less fibrosis and inflammation and less thickened bone and tympanic membranes than Gelfoam-packed ears. Surface preparations and SEM showed no ototoxicity in the inner ear of NasoPore-packed ears. CONCLUSION: NasoPore appears to be effective for use in otosurgery. It caused less fibrosis in the middle ear than conventional packing agents and no ototoxicity to the inner ear.

Diuretic activity of squamate mistletoe, Viscum angulatum.

Viscum angulatum Heyne ex DC (Viscaceae) is a leafless hemiparasitic shrub traditionally used in Asian countries for the treatment of hypertension. In the present study, the methanol extract of the whole plant was examined for diuretic activity in rats. The activity was evaluated using parameters such as urine volume after 5, 19, and 24 h and urine sodium, potassium, and chloride concentrations. The extract was further scrutinized for polyphenolic compounds and triterpenoids. The extract demonstrated a significant increase in and dose-dependent effect on urine excretion volume in comparison to the normal group in the tested range of 100-400 mg/kg. The extract demonstrated comparable saluretic and higher natriuretic activity (Na(+)/K(+)) compared to the furosemide treated group. However, the Cl(-)/Na(+) + K(+) ratio, which indicates carbonic anhydrase mediated activity, remained unaffected. HPLC and quantitative analysis of the extract revealed that polyphenolic compounds and the triterpenoid, oleanolic acid, are the major phytochemicals, and are proposed to be responsible for the observed diuretic effect. Oleanolic acid has been reported to possess diuretic activity with significant potassium loss in rats. In contrast to pure oleanolic acid, the extract demonstrated a valuable potassium-sparing effect. This suggests modulation of the diuretic effect of oleanolic acid by polyphenolics present in the extract. The observed dose-dependent potassium-sparing diuretic effect is a hereto unreported property of this plant.

Acute toxicity and diuretic studies of the roots of Asparagus racemosus willd in rats / Toxicidad aguda y estudios diuréticos del espárrago racemoso willd en ratas

OBJECTIVE: Asparagusracemosus Willd has been used as diuretic in Ayurveda but has not been validated by a suitable experimental model. Hence the present study was undertaken. MATERIALS AND METHODS: The study was carried out with an aqueous extract of the roots of Asparagus racemosus utilizing three doses viz 800 mg/kg, 1600 mg/kg and 3200 mg/kg for its diuretic activity in comparison with standard drug (furosemide) and control (normal saline) rats after doing acute toxicity study. RESULTS: Acute toxicity study showed no fatality even with the highest dose and the diuretic study revealed significant diuretic activity (p < 0.05) in the dose of 3200 mg/kg. CONCLUSION: Asparagus racemosus showed diuretic activity at a 3200 mg/kg dose without acute toxicity.

OBJETIVO: El espárrago racemoso Willd ha sido usado como diurético en ayurveda pero no ha sido validado mediante un modelo experimental conveniente. De ahí la razón para emprender el presente estudio. MATERIALES Y MÉTODOS: El estudio fue realizado con extracto acuoso de raíces de espárrago racemoso, utilizando tres dosis, a saber, 800 mg/kg, 1600 mg/kg y 3200 mg/kg para analizar su actividad diurética, comparándolo con el medicamento estándar (furosemida), y ratas de control (solución salina normal) después de hacer un estudio de toxicidad aguda. RESULTADOS: El estudio de toxicidad aguda no mostró fatalidad, incluso con la dosis más alta, y el estudio del diurético reveló una actividad diurética significativa (p < 0.05) con la dosis de 3200 mg/kg. CONCLUSIÓN: El espárrago racemoso mostró actividad diurética en una dosis de 3200 mg/kg sin toxicidad aguda.

Computational models for drug inhibition of the human apical sodium-dependent bile acid transporter.

The human apical sodium-dependent bile acid transporter (ASBT; SLC10A2) is the primary mechanism for intestinal bile acid reabsorption. In the colon, secondary bile acids increase the risk of cancer. Therefore, drugs that inhibit ASBT have the potential to increase the risk of colon cancer. The objectives of this study were to identify FDA-approved drugs that inhibit ASBT and to derive computational models for ASBT inhibition. Inhibition was evaluated using ASBT-MDCK monolayers and taurocholate as the model substrate. Computational modeling employed a HipHop qualitative approach, a Hypogen quantitative approach, and a modified Laplacian Bayesian modeling method using 2D descriptors. Initially, 30 compounds were screened for ASBT inhibition. A qualitative pharmacophore was developed using the most potent 11 compounds and applied to search a drug database, yielding 58 hits. Additional compounds were tested, and their K(i) values were measured. A 3D-QSAR and a Bayesian model were developed using 38 molecules. The quantitative pharmacophore consisted of one hydrogen bond acceptor, three hydrophobic features, and five excluded volumes. Each model was further validated with two external test sets of 30 and 19 molecules. Validation analysis showed both models exhibited good predictability in determining whether a drug is a potent or nonpotent ASBT inhibitor. The Bayesian model correctly ranked the most active compounds. In summary, using a combined in vitro and computational approach, we found that many FDA-approved drugs from diverse classes, such as the dihydropyridine calcium channel blockers and HMG CoA-reductase inhibitors, are ASBT inhibitors.

Amiloride derivatives induce apoptosis by depleting ER Ca(2+) stores in vascular endothelial cells.

BACKGROUND AND PURPOSE: Amiloride derivatives are blockers of the Na(+)/H(+) exchanger (NHE) and at micromolar concentrations have protective effects on cardiac and brain ischaemia/reperfusion injury but at higher concentrations also induce apoptosis. Here, we aimed to elucidate the mechanism related to this cytotoxic action. EXPERIMENTAL APPROACH: We quantified the expression of genes associated with endoplasmic reticulum (ER) stress and measured changes in luminal ER Ca(2+) concentration ([Ca(2+)](ER)) with a 'cameleon' indicator, D1ER. KEY RESULTS: Amiloride derivatives induced apoptosis in vascular endothelial cells, an effect that increased at alkaline extracellular pH. The potency order for cytotoxicity was 5-(N,N-hexamethylene)-amiloride (HMA) > 5-(N-methyl-N-isobutyl) amiloride > 5-(N-ethyl-N-isopropyl) amiloride (EIPA) >> amiloride. HMA dose-dependently increased the transcription of the ER stress genes GADD153 and GADD34 and rapidly depleted [Ca(2+)](ER), mimicking the effects of the sarco/endoplasmic reticulum ATPase (SERCA) inhibitor thapsigargin. The NHE1-specific inhibitor HOE 694 inhibited NHE activity by 87% but did not alter [Ca(2+)](ER). The decrease in [Ca(2+)](ER) evoked by amiloride derivatives was also observed in HeLa cells and was mirrored by an increase in cytosolic Ca(2+) concentration. CONCLUSIONS AND IMPLICATIONS: Amiloride derivatives disrupt ER and cytosolic Ca(2+) homeostasis by a mechanism unrelated to NHE inhibition, most likely by interfering with the activity of SERCA. We propose that ER Ca(2+) depletion and subsequent ER stress provide a rationale framework for the apoptotic effects of amiloride derivatives.

Hepatocytes isolated from preneoplastic rat livers are resistant to ethacrynic acid cytotoxicity.

Glutathione S-transferases (GSTs) are involved in the detoxification of xenobiotics, such as several cytostatic drugs, through conjugation with glutathione (GSH). Pi class GST (GST P) liver expression is associated with preneoplastic and neoplastic development and contributes with the drug-resistance phenotype. Ethacrynic acid (EA) is an inhibitor of rat and human GSTs. In addition, causes lipid peroxidation in isolated rat hepatocytes. Therefore, we decided to evaluate the role of the GST/GSH system in isolated hepatocytes from preneoplastic rat livers (IP) in the presence of EA and determine the cytotoxicity of the drug. Our results showed a resistance to the toxic effects of EA since viability and cellular integrity values were significantly higher than control. Initial levels of thiobarbituric acid reactive substances (TBARS) in IP hepatocytes were significantly higher than control and the presence of EA did not change TBARS levels. A diminution in intracellular total GSH was observed by treating with EA isolated hepatocytes from both groups. However, the initial total GSH levels were higher in IP hepatocytes than in control. Immunoblotting analysis showed the presence of GST P in IP animals only. Although alpha and mu class isoenzymes levels were decreased in IP hepatocytes, total GST activity was 1.5-fold higher than in control. In addition, multidrug-resistance protein 2 (Mrp2) showed fivefold decreased levels in IP hepatocytes. In conclusion, increased total GSH, decreased Mrp2 levels and the presence of GST P could be critical factors involved in the resistance of IP hepatocytes to the toxicity of EA.

Cell death after co-administration of cisplatin and ethacrynic acid.

Ethacrynic acid (EA) significantly enhances the ototoxic effects of cisplatin. To gain insights into the mechanisms underlying Cis/EA ototoxicity, cochleas were labeled with several apoptotic markers. Cis/EA treatment caused extensive outer hair cell (OHC) and inner hair cell (IHC) damage; OHC lesions decreased from the base towards apex of the cochlea whereas the IHC lesion was relatively constant (25-60%) along the length of the cochlea. Propidium iodide labeled OHC nuclei appeared relatively normal at 6h post-treatment, were condensed and fragmented at 12h post-treatment and were frequently missing 48 h post-treatment. Initiator caspase 8, associated with membrane death receptors, and TRADD, a protein that recruits caspase 8, were present in OHC at 6h post-treatment. Caspase 8 labeling increased from 6 to 24h, but was largely absent at 48 h post-treatment. Executioner caspase 3 and caspase 6, which lie downstream of caspase 8, were expressed in OHC 12-24h post-treatment. Initiator caspase 9, associated with mitochondrial damage, was only expressed at low levels at 48 h post-treatment. These results suggest that the rapid onset of Cis/EA induced programmed cell death is initiated by membrane death receptors associated with TRADD and caspase 8.

Tienilic acid enhances hyperbilirubinemia in Eisai hyperbilirubinuria rats through hepatic multidrug resistance-associated protein 3 and heme oxygenase-1 induction.

We demonstrated that tienilic acid, a diuretic drug withdrawn from the market because of hepatic failure, enhanced hyperbilirubinemia in Eisai hyperbilirubinuria rats (EHBR) with a defect of canalicular multidrug resistance-associated protein 2 (Mrp2). In contrast, no remarkable changes were noted in Sprague-Dawley (SD) rats, the parent strain for EHBR. To investigate a mechanism underlying this enhanced hyperbilirubinemia, we focused on comprehensive effects of tienilic acid on clinicopathological aspects and expression of hepatic transporters. Other than eventual hyperbilirubinemia with slightly increased biliary bilirubin, a single oral treatment of EHBR with tienilic acid at 300 mg/kg caused no changes in serum alanine aminotransferase and alkaline phosphatase, bile flow rate and biliary bile acid secretion, or hepatic morphology. In analyses of mRNA expression of the hepatic transporters, elevated Mrp3 expression in EHBR correlated with an increase in serum total bilirubin, suggesting increased bilirubin transport from the liver into the peripheral blood flow. Hepatic heme oxygenase-1 (Ho-1) mRNA, a stress-induced isoform of the rate-limiting enzyme in the catabolism of heme to bilirubin, was markedly upregulated in EHBR at the same dose at which increased serum bilirubin was seen. A time-course study revealed that marked induction of Ho-1 occurred earlier than that of Mrp3, followed by an increase in serum bilirubin. These results suggest that hepatic Mrp3 and Ho-1 may contribute to tienilic acid-enhanced hyperbilirubinemia in EHBR by inducing increased bilirubin transport from the liver into the blood stream, preceded by potentiation of bilirubin formation in the liver.

Hearing health and care: the need for improved hearing loss prevention and hearing conservation practices.

Hearing loss affects 31 million Americans, particularly veterans who were exposed to harmful levels of noise during military functions. Many veterans also receive treatment with ototoxic medications, which may exacerbate preexisting hearing loss. Thus, hearing loss is the most common and tinnitus the third most common service-connected disability among veterans. Poor implementation of hearing protection programs and a lack of audiometric testing during medical treatment leave veterans vulnerable to unrecognized and untreated hearing loss until speech communication is impaired. Individualized audiometric testing techniques, including assessment of high frequencies, can be used in clinical and occupational settings to detect early hearing loss. Antioxidants also may alleviate cochlear damage caused by noise and ototoxicity. Ultimately, hearing loss prevention requires education on reducing occupational and recreational noise exposure and counseling on the risks and options available to patients. Technological advances will improve monitoring, allow better noise engineering controls, and lead to more effective hearing protection.

Effect of spironolactone on cisplatin-induced nephrotoxicity in rabbits.

The effects of a single interaperitoneal dose of cisplatin (6.5 mg kg day(-1)), oral doses of spironolactone (20.0 mg kg day(-1)) for 5 days or the combined treatment (spironolactone+cisplatin) on the kidney function and liver function parameters, as well as the serum, liver and kidney cortical lipid contents were studied. The serum urea and creatinine concentrations (measured as kidney function parameters) were not altered by spironolactone treatment, but were significantly (P<0.001) elevated by cisplatin administration. However, animals exposed to both spironolactone+cisplatin revealed drastic increases in the serum creatinine and urea concentrations amounting to about four- and twofold those of cisplatin-alone treated animals, respectively. The histological examination of slides of kidneys from animals exposed to the combined drugs exhibited more extensive necrosis in the tubules compared to those from animals treated with cisplatin alone. Non of the drug treatments had any effects on the serum alanine transaminase (ALT) and aspartate transaminase (AST) levels (measured as liver function parameters) or liver protein content or hepatic alkaline phosphatase (ALP) activity. The histological examination also revealed apparently normal livers in all experimental groups. The cisplatin-induced nephrotoxicity was accompanied by hypercholesterolaemia and hyperphospholipidaemia, whereas spironolactone showed a hypocholesterolaemic effect. The concomitant treatment with both cisplatin and spironolactone significantly (P<0.05) raised the serum triacylglycerol (TAG) concentration compared to the cisplatin-alone-treated group. Both spironolactone and cisplatin administered separately or jointly caused accumulation of cholesterol and TAG in the kidney cortex with significant depletion of the liver cholesterol content. The present results indicated that spironolactone aggravates the cisplatin-induced nephrotoxicity in the rabbit.

The effect of combined administration of cadmium and furosemide on auditory function in the rat.

A number of heavy metals have been associated with toxic effects to the peripheral or central auditory system. These include lead, arsenic, mercury, platinum and organic tin compounds. In addition, the ototoxic effects of some metals may be potentiated by other factors. However, the auditory effects of cadmium have not previously been reported. The purpose of the present study was to investigate the potential ototoxic effects of cadmium from an acute dosage, and its potentiation by furosemide. Auditory brainstem response (ABR) thresholds were measured in adult Sprague-Dawley rats. Rats received either cadmium chloride (5 mg/kg, i.p.) followed by saline (4 ml/kg, i.p.). cadmium chloride followed by furosemide (200 mg/kg, i.p.), or furosemide alone. Follow-up ABRs were carried out 7 days post-treatment and threshold changes were compared between each treatment group. No significant threshold change was seen for the cadmium chloride plus saline treated or the furosemide treated animals. However, significant threshold elevations were observed in animals receiving cadmium chloride plus furosemide. In addition, scanning electron microscopy revealed extensive hair cell loss in animals treated with cadmium chloride and furosemide. Although functional auditory changes were not seen after the administration of cadmium alone, the potentiation of threshold changes by furosemide suggests that cadmium may be ototoxic under certain conditions.

Study of the photochemical and in vitro phototoxicity of chlortalidone [2-chloro-5-(1-hydroxy-3-oxo-1-isoindolinyl)benzene sulfonamide].

The photodegradation process of the phototoxic diuretic drug chlorthalidone was studied. The products of its photolysis under UV-B were isolated and identified. Chlorthalidone was found to be active when examined by photohemolysis on human erythrocytes, but not in the presence of the isolated photoproducts. Inhibition of the photohemolysis process induced by chlorthalidone on addition of reduced glutathione (GSH) or ascorbic acid suggests the involvement of radicals species. The inhibition with 1,4-diazabycyclo [2.2.2] octane (DABCO), sodium azide (NaN3) sowie 2,5-dimethylfuran proof the participation of singlet oxygen (1O2) in this process.

Immunosuppressive and cytotoxic effects of furosemide on human peripheral blood mononuclear cells.

BACKGROUND: We have previously shown that children with mild asthma have a modest improvement in their pulmonary function tests after aerosolized furosemide. The mechanism of action is not known. The observation that furosemide possesses a similar profile of protection as sodium cromoglycate and nedocromil sodium suggests that furosemide may inhibit mediator production and release. OBJECTIVE: We studied the in vitro effects of furosemide on cytokine release from normal human peripheral blood mononuclear cells (PBMC) induced by E. coli lipopolysaccharide (LPS). METHODS: Peripheral blood mononuclear cells were isolated by density gradient centrifugation, stimulated with LPS and incubated at 37 degrees C with varying concentrations of furosemide, hydrocortisone, sodium cromoglycate, and nedocromil sodium for 24 hours. Supernatants were extracted and study for levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and interleukin-8 (IL-8). Intracellular IL-6 and TNF-alpha concentrations were also measured by cell cytometry. Cell viability was examined using XTT cell proliferation test and-measuring the release of lactate dehydrogenase (LDH). RESULTS: There was a significant reduction in levels of TNF-alpha and IL-6 at a furosemide concentration of 0.5 x 10(-2) M and a reduction in IL-8 levels at 10(-2) M. This inhibition was comparable to that found with equivalent molar concentrations of hydrocortisone. These findings were also confirmed with measurements of intracellular IL-6 and TNF-alpha by cell cytometry. High concentration of furosemide at 10(-2) M caused significant cellular cytotoxicity. CONCLUSION: These data suggest that furosemide may exhibit an anti-inflammatory effect. Specifically, the addition of furosemide resulted in decreased production of cytokines. This effect may be due to an immunosuppressive activity on monocytes as well as a direct cytotoxic effect at high furosemide concentrations.