In-vivo gamma scintigraphic evaluation and determination of a gastro-resistant etodolac tablet in humans.

A gastro-resistant (enteric coated) etodolac tablet dosage form, was evaluated by using in vitro and in vivo methods. In vitro drug release studies have shown that enteric coated tablet dosage form protects the drug from being released under conditions mimicking stomach to small intestine transit. The gastro-intestinal transit of radiolabeled 300 mg enteric coated etodolac tablets in six healthy, fed and fasted state volunteers was monitored using external gamma camera. Dosage form position was reported at several time intervals. Etodolac serum concentrations were determined from serum samples drawn over 420 min following dosing. Differences in gastro-intestinal transit between fed and fasted volunteers had little effect on etodolac bioavailability. AUC, Tmax and C max values were calculated for both types of studies.

Effect of folic acid supplementation on aluminum accumulation in rats.

OBJECTIVE: Exposure to many xenobiotics may cause depletion of folic acid (folate), which is an essential vitamin for humans. Replacement of folate can be effective in protection against some diseases and in partial or total prevention of adverse effects related to xenobiotics. Aluminum (Al) is the most widely distributed metal in the outer crust of the earth. Its toxicity in humans is well known. However, there is no evidence that folate can decrease accumulation of Al to which humans can be exposed in many ways. The aim of the present study was to quantify organ Al accumulation and to evaluate whether there is any protective (or reductive) effect of folic acid on Al accumulation. METHODS: Male Wistar rats were assigned oral Al chloride (200 mg x kg(-1) x d(-1), n = 10, group 1) alone or in combination with folic acid (20 mg x kg(-1) x d(-1), n = 10, group 2) for 8 wk. At the end of the period, bone, kidney, brain, and blood samples were collected, and Al concentrations were determined by electrothermal atomic absorption spectrophotometry. RESULTS: Mean values of Al in the tissue samples from group 1 were higher than those from group 2 (all P < 0.05). No difference was observed in serum Al levels between groups (P > 0.05). CONCLUSION: These results suggest that folate supplementation might be useful to decrease Al accumulation in its main target organs, i.e., bone, kidney, and brain.

Preparation and in vitro evaluation of sustained release tablet formulations of diclofenac sodium.

The effects of formulation variables on the release profile of diclofenac sodium (DS) from hydroxypropylmethyl cellulose (HPMC) and chitosan matrix tablets were studied. DS tablets were prepared by wet granulation and direct compression methods and different ratios of HPMC and chitosan were used. Physical properties of the prepared tablets and targeted commercial sustained release (SR) tablet and the drug release were studied in tablets that were placed in 0.1 M HCl for 1 h and phosphate buffer solution was added to reach pH value of 7.5. In vitro studies showed that 20% HPMC contained SR formulation with direct (dry) compression method is the optimum formulation due to its better targeting profile in terms of release. This formulation also exhibited the best-fitted formulation into the zero order kinetics. The precision and accuracy of the analytical method were also checked. The repeatability and reproducibility of the method were also determined.

Increased vasoconstrictor reactivity and decreased endothelial function in high grade varicocele; functional and morphological study.

The pathophysiology of human varicocele is not fully understood. We investigated vasoconstrictor reactivity, endothelial function and morphological changes in different grades of varicocele to clarify the pathophysiology. Contractile responses to phenylephrine, norepinephrine, serotonin and histamine were determined in isolated human varicose spermatic veins using the organ bath technique. Endothelial function was tested with acetylcholine-induced relaxation after phenylephrine-induced precontraction in the absence and presence of nitric oxide synthase inhibitor, L-NAME, and cyclooxygenase inhibitor, indomethacin. The cyclic guanosine monophosphate (cGMP) level was measured in the spermatic vein and peripheral plasma. Morphological changes were evaluated with light microscopy. Phenylephrine, norepinephrine, serotonin and histamine induced concentration-dependent contractions. The maximum contractions for all of these agents except norepinephrine were significantly higher in grade III than grade I and II (P<0.05). The sensitivity to phenylephrine was significantly higher in grades II and III than in grade I (P<0.05). In the presence of L-NAME and indomethacin, the difference from respective control phenylephrine-induced contractions was higher in grade I and II than grade III. Acetylcholine did not induce stable relaxation but the level of cGMP, which is responsible for the vasorelaxant effect of NO, in veins was lower in grades II and III than grade I (P<0.05). Vessel wall thickness increased in grade II and dilatation developed in grade III when compared to grade I (P<0.05). Our findings suggest that endothelium produces less vasorelaxant which results in the more enhanced effects of vasoconstrictor substances in grade III, indicating that endothelial dysfunction develops at high grades of varicocele.

Accumulation of aluminum in rat brain: does it lead to behavioral and electrophysiological changes?

The present study was undertaken to examine possible aluminum (Al) accumulation in the brain of rats and to investigate whether subchronic exposure to the metal leads to behavioral and neurophysiological changes in both treated and control groups. Each of the groups consisted of 10 animals. Aluminum chloride (AlCl3) at a low (50 mg/kg/d) or high (200 mg/kg/d) dose was applied to male Wistar rats by gavage for 8 wk. Al-free water by gavage was given to the control group throughout the experiment. Behavioral effects were evaluated by open-field (OF) motor activity and by acoustic startle response (ASR). Electrophysiological examination was done by recording spontaneous activity and sensory-evoked potentials from the visual, somatosensory, as well as auditory cortex. The Al content of each whole brain was determined by electrothermal atomic absorption spectrophotometry. Subchronic Al exposure slightly caused some changes in the evoked potentials and electrocorticograms and in the OF and ASR performance, but these results were not statistically significant. The brain Al levels of the control and the low and high dose of Al-exposed groups were measured as 0.717+/-0.208 microg/g (wet weight), 0.963+/-0.491 microg/g (wet weight) and 1.816+/-1.157 microg/g (wet weight), respectively.

Neopterin as a new biomarker for the evaluation of occupational exposure to silica.

OBJECTIVES: Silica is one of the most documented workplace contaminants. Long-term occupational exposure to silica is associated with an increased risk for respiratory diseases such as silicosis, tuberculosis, chronic bronchitis, chronic obstructive pulmonary disease and lung cancer. Furthermore, a variety of immune-dysfunction-related diseases has been reported in silicotic individuals. Preliminary studies indicating enhanced levels of autoantibodies and several cytokines reflect an involvement of the immune system in the pathogenesis of silicosis and resulting complications. As an early and valuable biomarker of cellular immunity, neopterin is a low-molecular-mass compound belonging to the class of pteridines. It is produced by guanosine triphosphate via interferon-gamma, following the activation of T cells. The aim of the present study was to observe the alteration of neopterin in silica exposure, and also to show whether screening of neopterin levels may be of use for assessment of occupational exposure to silica. METHODS: In this study, serum and urinary neopterin levels, both in silica-exposed workers ( n=22) and healthy volunteers ( n=20), were investigated by ELISA, spectrophotometry and HPLC techniques. RESULTS: Serum neopterin levels of control and exposed groups were measured as 5.98+ or -0.44 and 7.86+ or -1.97 nmol/l, respectively ( P<0.05). Urinary neopterin levels were also increased in the exposed group: 97.60+ or -41.42 micromol/mol creatinine for controls and 165.59+/-78.20 micromol/mol creatinine for workers ( P<0.05). At the same time, the correlation between urinary neopterin levels, serum neopterin concentration and working years, smoking status, some complaints, and silica status in the working atmosphere were evaluated. CONCLUSIONS: Our findings suggest that the following up of neopterin levels may have diagnostic value in silica-related diseases such as silicosis. Moreover, its biological monitoring should be performed in workplaces for clinical diagnosis and prognosis.

Influence of the delta-aminolevulinic acid dehydratase (ALAD) polymorphism on biomarkers of lead exposure in Turkish storage battery manufacturing workers.

BACKGROUND: The relationship between delta-aminolevulinic acid dehydratase polymorphism (ALAD) and biomarkers of exposure was investigated in Turkish lead workers in this study. METHODS: Seventy two male lead battery manufacturing workers were selected for the study. Blood lead (BPb) and urinary lead (UPb) concentrations were determined by atomic absorption spectrometry. Erythrocyte ALAD activity and urinary 5-aminolevulinic acid (UALA) were measured spectrophotometrically. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used to determine the genotype of the ALAD gene. RESULTS: In total, 51 workers (70.8%) had the ALAD 1-1 genotype, whereas 21 workers (29.2%) had the ALAD 1-2 genotype. No significant relationships were found between the two genotypes and BPb, UPb, and ALAD activity. ALAD1 homozygotes showed significantly higher levels of UALA in comparison with those ALAD2 carriers. CONCLUSIONS: ALAD 1-1 individuals might be an increased risk compared to ALAD2 carriers to disturbance in heme biosynthetic pathway in high lead exposure.

Pharmacologic characterization of contractile serotonergic receptors in human isolated mesenteric artery.

The 5-hydroxytryptamine (5-HT) receptors mediating contraction in human isolated mesenteric arteries were characterized. Endothelium-denuded human isolated mesenteric arteries were used. 5-HT induced concentration-dependent contractions in mesenteric arteries (Emax, 127.37 +/- 7.61% of 80 mM KCl maximal contraction; pD2, 6.73 +/- 0.09 [-logEC50]). Sumatriptan, a selective 5-HT1B/1D receptor agonist, induced concentration-dependent contractions in some of the arteries (Emax, 61.82 +/- 10.04%; pD2, 6.56 +/- 0.21, n = 9) but not in the others (Emax < 5%, n = 13), suggesting that functional 5-HT1B/1D receptors exist in some but not in all mesenteric arteries. GR127935 (a selective 5-HT1B/1D receptor antagonist, 3 nM) inhibited sumatriptan-induced contractions in arteries in which sumatriptan responses were strong in an insurmountable manner. GR127935 (10 nM) also inhibited 5-HT responses and shifted the concentration-response curve of 5-HT to the right significantly (p < 0.05; pD2s were 6.54 +/- 0.18 and 5.93 +/- 0.11 in the presence of vehicle and GR127935, respectively). Ketanserin (0.01-1 microM) competitively antagonized 5-HT responses in human mesenteric arteries: pA2 value was 8.40 +/- 0.25 (slope of Schild regression, 1.43 +/- 0.18; r2, 0.98). Tropisetron (5-HT3 receptor antagonist) and prazosin (alpha1-adrenoceptor antagonist) did not affect the contractions induced by 5-HT. These results suggest that 5-HT2A and 5-HT1B/1D receptors, but not 5-HT3 and alpha1-adrenoceptors, are involved in the 5-HT-induced contractions in human isolated mesenteric arteries. Sumatriptan-induced and 5-HT1B/1D receptor-mediated responses vary greatly among patients.

Increased oxidative stress and hypozincemia in male obesity.

OBJECTIVES: Antioxidants protect an organism from the detrimental effects of free radicals via scavenging or inhibiting their formation. Alterations in the levels of antioxidants and several essential trace elements in the plasma and various tissues of ob/ob mice have been reported previously. The aim of this study was to investigate oxidative status and trace elements in obese individuals. DESIGN AND METHODS: Seventy-six obese men (body mass index (BMI) > 30 kg/m(2)) and 24 healthy, age-matched male control volunteers were enrolled in the study. Fasting plasma insulin, glucose, triglyceride (TG), total cholesterol, VLDL, and HDL levels, erythrocyte glutathione peroxidase (GSH-Px) and copper zinc-superoxide dismutase (CuZn-SOD) activities, and erythrocyte thiobarbituric acid reactive substances (TBARS) levels were measured in both groups. Erythrocyte copper (Cu), zinc (Zn) and iron (Fe) levels were also measured. RESULTS: We found that the mean Cu and Fe levels in obese individuals were not significantly different than those in the control group, whereas the mean Zn levels were significantly lower than those of the control group (p = 0.023). The mean erythrocyte CuZn-SOD and GSH-Px levels in obese individuals were significantly lower than those in controls (p = 0.001) whereas erythrocyte TBARS levels were significantly higher (p = 0.001) than those of the control group. CONCLUSION: We conclude that male obesity is associated with defective antioxidant status and hypozincemia, which may have implications in the development of obesity related health problems.

Combined effects of cadmium and nickel on testicular xenobiotic metabolizing enzymes in rats.

When male rats were given a single dose of cadmium (Cd) (3.58 mg CdCl2 x H2O/kg, i.p.) 72 hr prior to sacrifice, the testicular 7-ethoxyresorufin O-deethylase (EROD) and glutathione S-transferase (GST) activities toward the substrates 1-chloro-2,4-dinitrobenzene (CDNB), 1,2-dichloro-4-nitrobenzene (DCNB), ethacrynic acid (EAA), 1,2-epoxy-3-(p-nitrophenoxy)-propane (EPNP), and cumene hydroperoxide (CHPx) decreased significantly as compared to controls. Cd also inhibited reduced glutathione (GSH) level while increasing the lipid peroxidation (LP) level significantly. When the animals were given a single dose of nickel (Ni) (59.5 mg NiCl2 x 6H2O/kg, i.p.) 16 hr prior to sacrifice, significant decreases were observed in EROD and GST activities toward CDNB, EAA, EPNP, and CHPx, and GSH level. No significant alterations were noted in DCNB GST activity and LP level by Ni. For the combined treatment, rats received the single dose of Ni 56 hr after the single dose of Cd and were killed 16 hr later. In these animals, lesser depressions were observed on EROD activity and LP level than those of Cd alone. The combination of metals significantly inhibited GST activities and GSH level but not to a greater degree than noted by Cd or Ni alone. Plasma testosterone levels of Cd-, Ni-, and combination-treated rats decreased significantly compared to controls. The strongest depression was achieved by Cd alone. Cd, both alone and in combination with Ni, increased the tissue Ni uptake significantly. Ni, however, did not produce such an effect on the tissue uptake of Cd in either case. Cd treatment caused interstitial edema and coagulation necrosis in seminiferous tubules and also caused fibrinoidal necrosis in vascular endothelium. Ni treatment did not produce any pathological testicular alterations compared to controls. Combined treatment produced fewer pathological alterations (i.e., only interstitial edema) than that of Cd treatment. These results reveal that the combination of Cd and Ni does nothave a synergistic effect on testicular xenobiotic metabolizing enzymes, and in contrast, Ni has an ameliorating effect on pathological disturbances caused by Cd alone in the rat testis.

The interaction between IL-1beta and morphine: possible mechanism of the deficiency of morphine-induced analgesia in diabetic mice.

It is known that diabetic mice are less sensitive to the analgesic effect of morphine. Some factor(s) derived from mononuclear cells, e.g. interleukin-1beta (IL-1beta), may be responsible for the diminished analgesic effect of morphine in diabetic mice. Therefore, we examined direct effects of IL-1beta, intracerebroventricularly (i.c.v.), on morphine-induced analgesia, subcutaneously (s.c.), in diabetic and control mice by using the tail-flick test. Morphine at doses of 1, 2 and 5 mg/kg (s.c.) produced dose-dependent analgesia in diabetic and control mice but diabetic mice were less sensitive to the analgesic effect of morphine when compared to the controls. IL-1beta at a dose of 0.1 ng/mouse produced analgesia in control mice but not in diabetics, whereas IL-1beta at a dose of 10 ng/mouse produced a hyperalgesic effect both in diabetic and control mice. IL-1beta at a dose of 1 ng/mouse has neither an analgesic nor a hyperalgesic effect in control and diabetic mice. Administration of a neutral (neither analgesic nor hyperalgesic) dose of IL-1beta, 1 ng/mouse (i.c.v.), just prior to administration of morphine (s.c.) abolished the analgesic effect of morphine at doses of 1, 2 and 5 mg/kg in control mice and the analgesic effect of morphine became similar to that in diabetics. The diminished analgesic effect of morphine in diabetes was attenuated further with IL-1beta at a dose of 1 ng/mouse (i.c.v.). These results suggest that the decreased analgesic effect of morphine in diabetes may be related to IL-1beta.