Simultaneous determination of gemcitabine and its metabolite in human plasma by high-performance liquid chromatography

Gemcitabine (dFdC) is a pyrimidine antimetabolite with broad spectrum activity against tumors. In this paper, a normal-phase high-performance liquid chromatographic method was developed for the determination of the parent drug (dFdC) and its metabolite (dFdU) in human plasma. The described sample preparation procedure for determination of dFdC and dFdU is rapid, sensitive, reproducible and simple. The linear regression equations obtained by least square regression method, were area under the curve=0.0371 concentration (ng ml(-1))+192.53 and 1.05.10(-4) concentration (ng ml(-1))-1.2693 for dFdC and dFdU, respectively. The assay for dFdC and dFdU described in the present report has been applied to plasma samples from a bladder cancer patient.     

Impact of Helicobacter pylori on the development of vitamin B12 deficiency in the absence of gastric atrophy

Background. Cobalamin (vitamin B₁₂) deficiency is associated with Helicobacter pylori infection. This study examined how serum vitamin B₁₂ levels relate to gastric mucosa H. pylori density and histology, and to hematological findings in patients with minimal or no gastric atrophy. A second aim was to confirm that H. pylori eradication therapy increases serum B₁₂. Materials and Methods. Biopsies of the gastric mucosa from a population of dyspeptic patients were graded for level of chronic inflammation, neutrophil activity, atrophy, and H. pylori density. A total of 145 H. pylori‐infected patients with minimal or no atrophy were included in the study. Serum cobalamin level, hemoglobin level, and mean corpuscular volume were measured in the 145 patients before eradication therapy, and in 65 of the subjects after treatment. The hematologic findings before and after eradication therapy and correlations between serum vitamin B₁₂ level and histologic parameters, hematologic findings, and patient age were statistically analyzed. Results. There was no significant correlation between serum cobalamin level and patient age. Before treatment all the histopathological scores were inversely correlated with serum vitamin B₁₂ level (p < .01) on univariate analysis. Only H. pylori density was significantly associated with B₁₂ level on multivariate analysis. Serum hemoglobin and cobalamin levels were significantly increased after treatment, regardless of H. pylori eradication status (p < .001). Conclusion. The findings provide strong evidence that H. pylori infection is associated with cobalamin deficiency, and show that this is true even in patients with nonulcer dyspepsia and minimal or no gastric atrophy.     

Comparison of two methods (microscopy and enzyme-linked immunosorbent assay) for the diagnosis of amebiasis

Diagnosis of amebiasis is usually performed on a clinical basis alone in most endemic countries having limited economic resources. This epidemiological study was conducted using modern diagnostic tests for amebiasis in the southeastern region of Turkey, an endemic area for amebiasis. The population of this study included patients with symptomatic diarrhea/dysentery attending both Yuzuncu Yil University, Van and Harran University, Sanliurfa, Turkey. A total of 380 stool specimens were collected and examined for Entamoeba by light microscopy (fresh, lugol, and trichrome staining) and stool antigen detection based- enzyme-linked immunosorbent assay (EIA) test (TechLab Entamoeba histolytica II). 24% (91/380) of stool specimens were positive for E. histolytica/Entamoeba dispar trophozoites/cysts microscopically using trichrome staining. 13% (51/380) of the stool specimens were found to be positive for E. histolytica by the EIA test, including 15% (14/91) of microscopy (+) stool specimens and 13% (37/289) of microscopy (-) stool specimens. Enteric parasites were common in these populations with 66% (251/380) of the study population harboring more than one parasite. In addition to the 13% (51/380) of patients determined to have E. histolytica by EIA, eighty-six patients (22.6%) had Blastocystis hominis, 54 (14.2%) Entamoeba coli, 44 (11.5%) Giardia lamblia, 16 (4.2%) Chilomastix mesnili, 15 (3.9%) Iodamoeba bütschlii, 12 (3.1%) Hymenolepis nana, 9 (2.3%) Endolimax nana, 9 (2.3%) Dientamoeba fragilis, and 8 (2.1%) had Ascaris lumbricoides. We concluded that E. histolytica infection was found in 13% of the patients presenting with diarrhea in Van and Sanliurfa Turkey.     

Effects of high dose retinoic acid on TGF-β2 expression during pancreatic organogenesis

Summary The aim of this study was to investigate the effects of excess all-trans retinoic acid, a vitamin A metabolite, on pancreatic organogenesis and TGF-β2 expression during prenatal development in rats.First group of animals used as control while a single dose of 60 mg/kg all-trans retinoic acid was ingested by the mothers, at day 8 of gestation (before the neurulation period) in group II and at day 12 of gestation (after the neurulation period) in group III, and all embryos were sacrificed at day 18 of gestation. TGF-β2 expression was detected in the capsule, acini and Langerhans islets in the control group. In the pancreas of group II, dilatation and congestion of interlobular vessels were observed. Langerhans islet structures were completely absent. Moreover acinar TGF-β2 immune reactivity was not determined. In group III, acinar expression of TGF-β2 in acid was similar to that in the controls but their Langerhans islets TGF-β2 immune reactivity was significantly less than the controls.In view of the present findings we suggest that TGF-β2 plays important role in pancreatic morphogenesis and administration of excess all-trans retinoic acid before neurulation inhibit TGF-β2 expression disrupted pancreatic morphogenesis particularly Langerhans islets. However, its administration after neurulation had less adverse affect on pancreatic organogenesis and TGF-β2 immune reactivity.     

Drug susceptibility testing of Mycobacterium tuberculosis by the broth microdilution method with 7H9 broth

In this study, we have evaluated the broth microdilution method (BMM) for susceptibility testing of Mycobacterium tuberculosis. A total of 43 clinical isolates of M. tuberculosis and H37Rv as a control strain were studied. All isolates were tested by the proportion method and the BMM for isoniazid (INH), rifampicin (RIF), streptomycin (STR), and ethambutol (ETM). The proportion method was carried out according to the National Committee for Clinical Laboratory Standards (NCCLS) on L?wenstein-Jensen (LJ) medium. The BMM was carried out using 7H9 broth with 96 well-plates. All strains were tested at 3.2-0.05 micro g/ml, 16-0.25 micro g/ml, 32-0.5 micro g/ml, and 32-0.5 micro g/ml concentrations for INH, RIF, STR, and ETM, respectively. When the BMM was compared with the proportion method, sensitivity was 100, 100, 96.9, and 90.2%, while specificity was 100, 85.7, 90.9, and 100% for INH, RIF, STR, and ETM, respectively. The plates were examined 7, 10, 14, and 21 days after incubation. The majority of the result were obtained at 14th days after incubation, while the proportion method result were ended in 21-28 days. According to our results, it may be suggested that the BMM is suitable for early determining of multidrug-resistance-M. tuberculosis strains in developed or developing countries.     

Antioxidant system activation in prostate cancer

The activities of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) and the levels of copper, zinc, and malondialdehyde were determined in 21 age-, sex-, and body-mass-index-matched prostate cancer patients; 50 patients diagnosed with benign prostatic obstruction (BPO) were compared to 50 healthy male subjects acting as controls. The patients were divided into two groups depending on the stage of the disease (group 1 [organ-confined] and group II [advanced disease]) and into three subgroups according to differentiation criteria: subgroup A (n=5, Gleason sum 2–4, well differentiated); subgroup B (n=9, Gleason sum 5–7, moderately differentiated), and subgroup C (n=7, Gleason sum 8–10, poorly differentiated). The MDA levels were higher and the antioxidant activity and Zn levels lower in the prostate cancer groups than in the healthy control and BPO groups. These results confirm the value of therapies aimed at increasing the antioxidant capacity and encourage the use of plasma and erythrocyte Zn levels in the differential diagnosis of BPO and prostate cancer. The MDA levels can be used in the diagnosis and follow-up of prostate cancer.     

Protective effects of intraperitoneal vitamin C, aprotinin and melatonin administration on retinal edema during experimental uveitis in the guinea pig

A considerable amount of clinical and experimental evidence exists suggesting the involvement of reactive oxygen substances (ROS) in the aetiology of uveitis. The activated phagocytic system of polymorphonuclear leucocytes in uveitis is involved in the generation of ROS. In addition to their direct free radical scavenging action, aprotinin, melatonin and vitamin C are known to protect against oedema formation and can preserve plasma membrane fluidity and free radical production. Histological changes in the retina that occur during uveitis are not well explained. The purpose of this study was to determine whether vitamin C, aprotinin and melatonin can protect the retina from damage accompanying experimental uveitis (EU). Thirty adult male guinea pigs were divided into five groups of six animals each. The first group was used as control. The right eyes of groups 2, 3, 4 and 5 received an intravitreal injection of bovine serum albumin for induction of experimental uveitis. At the same time and also on the consecutive third day, groups 3, 4 and 5 received intraperitoneal injections of vitamin C (ascorbic acid, 100 mg kg(-1) body wt), aprotinin (20,000 kIU kg(-1) body wt) and melatonin (10 mg kg(-1) body wt), respectively. The animals were killed on the sixth day. The average thickness of the retina and inner plexiform layer for each eye was measured in sagittal section near the optic nerve and expressed in microns. The thickness of the retina and inner plexiform layer in the control group was significantly (p < 0.01) lower than in the group EU as compared with the group EU plus vitamin C, group EU plus aprotinin, group EU plus melatonin (p < 0.05). The thicknesses of the retina and inner plexiform layer in group EU plus vitamin C, group EU plus aprotinin and group EU plus melatonin were significantly (p < 0.01) lower than that in the group EU. The difference in thickness of the retina and inner plexiform layer among the groups 3, 4 and 5 was not significant (p > 0.05). In conclusion, this study demonstrated that oedematous effects of EU on the retina were reduced by the administration of intraperitoneal vitamin C, aprotinin and melatonin, i.e. these antioxidants had significant protective effects on the retina of guinea pigs against oedematous damage in EU. However, the reductive effect of vitamin C on EU was greater than that of aprotinin and melatonin. The intraperitoneal vitamin C, aprotinin and melatonin supplementations may strengthen the antioxidant defence system because of decreased ROS, and these agents may play a role in treating uveitis.     

Toxicity of gold nanoparticles functionalized with cationic and anionic side chains

The structure and properties of gold nanoparticles make them useful for a wide array of biological application. Toxicity, however, has been observed at high concentrations using these systems. MTT, hemolysis, and bacterial viability assays were used to explore differential toxicity among the cell types used, using 2 nm core particles. These studies show that cationic particles are moderately toxic, whereas anionic particles are quite nontoxic. Concentration-dependent lysis mediated by initial electrostatic binding was observed in dye release studies using lipid vesicles, providing the probable mechanism for observed toxicity with the cationic MMPCs.