Scope of detection and determination of gallium(III) in industrial ground water by square wave anodic stripping voltammetry on bismuth film electrode.

Gallium(III) in ground water may cause human health hazards due to the antineoplastic and antimicrobial activities of gallium. However, the exposure limit of Ga(III) has not been set. This paper demonstrates the scope of employing the square wave anodic stripping voltammetry (SWASV) on bismuth film electrode (BiFE) for selective and sensitive detection of Ga(III) as well as its accurate and precise determination. The key parameters were optimized and the bismuth film morphology was characterized. The performance of BiFE was also compared with that of the mercury film electrode (MFE). The performance of BiFE was also studied for interferences of Zn(II), Cd(II), Tl(I) and Cu(II) ions. Gaussian peak fitting was performed to improve the calibration curve and the fitting process revealed almost similar stripping peak heights as obtained from the experimentally observed data though slight improvement in calibration was obtained from the peak area analysis. A good linear dynamic range (R(2)=0.996) was obtained in the concentration range of 20-100 µg/L with a limit of detection (LOD) of 6.6 µg/L (S/N=3) of Ga(III). A relative standard deviation of 2.9% (n=10) was obtained for 20 µg/L of Ga(III) solution. The practical analytical utility of the method was verified by the determination of Ga(III) in spiked water samples, where 100-105% recovery of Ga(III) was achieved.

Free radical induced damages to rat liver subcellular organelles: inhibition by Andrographis paniculata extract.

Aqueous extract of Andrographis paniculata was examined for antioxidant activity using rat liver subcellular organelles as model systems. The study deals with two important biological oxidative agents, ascorbate-Fe(+2) and AAPH generating hydroxyl and peroxyl radical, respectively. Oxidative damage was examined against the inhibition of membrane peroxidation, protein oxidation and restoration in decreased SOD and catalase activity. The antimutagenic activity of Ap was examined following inhibition in AAPH induced strand breaks in plasmid pBR322 DNA. Extract was a potent scavenger of DPPH, ABTS radicals, exemplified by ESR signals, O2-*, *OH and H2O2, displayed excellent reducing power, FRAP potentials to reduce Fe (III) --> Fe (II) and had considerable amount of phenolics/ flavonoids contents, an effective antioxidant index. The observed antioxidant effect might be primarily due to its high scavenging ability for ROS. Effect was confirmed ex vivo following inhibition in peroxidation, restoration in SOD enzyme, SOD band intensity and protein degradation in Ap fed liver homogenate. Based on these results, it was concluded that the aqueous extract of Andrographis paniculata might emerge as a potent antiradical agent against various pathophysiological oxidants.

Free radical scavenging reactions and antioxidant activity of embelin: biochemical and pulse radiolytic studies.

Embelin (from Embelia ribes) is a component of herbal drugs and possess wide range of medicinal properties. These properties may be, in part, due to scavenging of oxidizing free radicals. In this context, free radical scavenging reactions and antioxidant activity of embelin (2,5-dihydroxy-3-undecyl-1,4-benzoquinone) have been studied. It has been found to scavenge DPPH radical and inhibit hydroxyl radical induced deoxyribose degradation. It has been also found to inhibit lipid peroxidation and restore impaired Mn-superoxide dismutase in rat liver mitochondria. Further, kinetics and mechanism of the reactions of embelin with hydroxyl, one-electron oxidizing, organo-haloperoxyl and thiyl radicals have been studied using nanosecond pulse radiolysis technique. Its redox potential has been also evaluated with cyclic voltammetry. These studies suggest that embelin can act as a competitive antioxidant in physiological conditions.

Immunological response to two hepatitis B vaccines administered in two different schedules.

OBJECTIVES: To evaluate the antibody response to a plasma derived hepatitis B vaccine containing pre-S and S antigens and a recombinant vaccine containing only S antigen and compare the two vaccines in 0, 1, 2 and 0, 1, 6, schedules METHODS: One hundred fifty nine healthy infants were randomized to receive the vaccines in two different schedules. Anti HBs titers were estimated prior to the vaccination and then one-month following the second and third doses. RESULTS: Both the vaccines produced a high rate of seroconversion and seroprotection. The antibody response was similar with both the vaccines and the 0, 1, 6, schedule induced a significantly higher antibody level than the 0, 1, 2, schedule. CONCLUSION: 0, 1, 6 schedule produces a higher antibody level than 0, 1, 2 schedule though both the schedules have good seroconversion and seroprotection rates with both the vaccines.

Peroxynitrite: a potent oxidizing and nitrating agent.

Nitric oxide (NO*) reacts with superoxide (O2-*) forming peroxynitrite (PXN) (ONOO-), a strong oxidant which reacts with several biomolecules leading to enormous implications in biological process, holds enormous implications for the understanding of free radicals. The ONOO- formation in vivo has significant implications in free radical biology. It exerts a defensive role in large number of pathophysiological reactions and also acts as signaling molecule in activation of several protooncogenes. It decomposes rapidly to an intermediate and reacts with several biomolecules. Evidence for PXN formation in vivo has been obtained immunohistochemically through detection of a characteristic reaction product with protein tyrosine residues and 3-nitrotyrosine. This "biomarker" of PXN formation has now been identified in various pathologies such as Lou Gehrig's disease, Parkinson's disease, cancer, atherosclerosis as well as in biological aging. 3-nitrotyrosine formation has been documented in various tissues, e.g. even in non-diseased embryonic heart during normal development. Therefore, there is a great opportunity in the postgenomic period to understand the interplay of these molecular interactions with biological events such as apoptosis, gene regulation etc. This review deals with biological significance of peroxynitrite, its precursors, reactions with large range of biomolecules, including aminoacids, proteins, lipids, nucleic acids, antioxidants as well as cytotoxic aspects.

Necrotizing myelitis in an immunocompetent child: a case report with review of literature.

A few cases of necrotizing myelitis have been reported in adults since its first description in 1973. No case has been described in the pediatric age group. A 12-year-old boy, who presented with acute flaccid paraplegia, loss of sphincter control and sensory loss showed features suggestive of necrotizing myelitis on magnetic resonance imaging. Investigations carried out could not reveal a specific etiological or pre-disposing factor. No clinical improvement occurred despite the therapy.

An unusual case of biliary atresia.

Intrahepatic biliary cysts are rarely seen in the patients with biliary atresia. We describe a ten-month-old child with biliary atresia in whom the abdominal imaging studies (ultrasonography, computed tomographic scan and magnetic resonance cholangiopancreatography) revealed multiple intrahepatic biliary cysts ('bile lakes'). The child also had intrapulmonary shunting of blood due to pulmonary arteriovenous fistulae, which were demonstrated on contrast-enhanced echocardiography. Both these findings, 'bile lakes' and pulmonary arteriovenous fistulae occur rarely in biliary atresia.

Infantile tremor syndrome and zinc deficiency.

Infantile tremor syndrome is characterized by coarse tremors, mental and physical retardation, light colored brown hair, skin pigmentation and anemia. Amongst the theories proposed for the etilogy of the disorder, the nutritional theory is most accepted. In this case report, we have presented a fourteen-month-old male child with ITS and documented zinc deficiency. Though most of the previous workers have proposed vitamin-B12 deficiency as the etimology for ITS, our report suggests that zinc deficiency could also have a causative role.

Pulmonary arteriovenous malformations.

Pulmonary arteriovenous malformations rarely present in childhood. Two cases are presented in this report. Both the cases presented clinically with cyanosis and clubbing without a cardiac murmur. The second case had cerebral abscess in addition. Both the cases underwent a contrast-enhanced echocardiography which suggested the presence of pulmonary arteriovenous malformations. The first case also underwent 99mTc radionuclide scan and pulmonary angiography. The cases are being reported for their characteristic clinical features and for emphasizing the role of non-invasive modalities like contrast-enhanced echocardiography and radionuclide scan in reaching the diagnosis.

Glanzmann's thrombasthenia.

Glanzmann's thrombasthenia (GT) is an uncommon cause of bleeding in children. We diagnosed two siblings as having GT on the basis of flow cytometric studies. Both had cutaneous bleedings and epistaxis since early childhood. Hematological investigations revealed prolonged bleeding time and a normal platelet count. Both the patients had absence of aggregation of platelets with the agonist adenosine diphosphate. Absence of the GPIIb/IIIa receptor was confirmed by flow cytometry. A short review of the disorder is presented.

Thyroiditis as a presenting feature of mumps.

Thyroiditis complicating mumps is rare and occurs 1 week after the parotitis. A 9-year-old boy with a history of contact with a case of mumps presented with thyroid swelling. Thyroid scan showed a diffusely reduced uptake. The aspiration cytology showed lymphocytic thyroiditis. Thyroid function tests were normal and antithyroid antibodies were absent. Parotitis occurred 12 days after the onset of thyroiditis.

Chlorophyllin as an effective antioxidant against membrane damage in vitro and ex vivo.

Chlorophyllin (CHL), the sodium-copper salt and the water-soluble analogue of the ubiquitous green pigment chlorophyll, has been attributed to have several beneficial properties. Its antioxidant ability, however, has not been examined in detail. Using rat liver mitochondria as model system and various sources for the generation of reactive oxygen species (ROS) we have examined the membrane-protective properties of CHL both under in vitro and ex vivo conditions. Oxidative damage to proteins was assessed as inactivation of the enzymes, cytochrome c oxidase and succinic dehydrogenase besides formation of protein carbonyls. Damage to membrane lipids was measured by formation of lipid hydroperoxides and thiobarbituric acid reactive substances. The effect of this compound on the antioxidant defense system was studied by estimating the level of glutathione and superoxide dismutase. ROS were generated by gamma-radiation, photosensitization, ascorbate-Fe(2+), NADPH-ADP-Fe(3+) and the peroxyl radical generating agent, azobis-amidopropane hydrochloride. Our results show that CHL is highly effective in protecting mitochondria, even at a low concentration of 10 microM. The antioxidant ability, at equimolar concentration, was more than that observed with ascorbic acid, glutathione, mannitol and tert-butanol. When CHL was fed to mice at a dose of 1% in drinking water, there was a significant reduction in the potential for oxidative damage in cell suspensions from liver, brain and testis. To examine the possible mechanisms responsible for the observed antioxidant ability we have studied the reaction of CHL with the potent ROS in the form of hydroxyl radical and singlet oxygen. The compound shows a fairly high rate constant with singlet oxygen, in the order of 1.3x10(8) M(-1) s(-1). In conclusion, our studies showed that CHL is a highly effective antioxidant, capable of protecting mitochondria against oxidative damage induced by various ROS.

Differential modification by caffeine of oxygen-dependent and independent effects of gamma-irradiation on rat liver mitochondria.

PURPOSE: Following the demonstration that caffeine effectively competes with oxygen for electrons and also scavenges hydroxyl radicals and singlet oxygen, the differential modification of oxygen-dependent and independent effects of gamma-radiation by caffeine in membranes was examined, using rat liver mitochondria as a model system. MATERIALS AND METHODS: Mitochondria were isolated from the livers of Wistar rats and exposed to gamma-radiation in the dose range of 45-600 Gy (dose rate 15 Gy/min) in the presence or absence of caffeine. To examine the 'oxygen effect', post-irradiation incubation was carried out in the presence of oxygen or nitrogen in buffers saturated with the respective gases. Membrane damage was examined as lipid peroxidation (assessed as formation of thiobarbituric acid-reactive substances (TBARS), lipid hydroperoxides (LOOH) and conjugated dienes (CD), protein oxidation, depletion of protein thiols, superoxide dismutase or glutathione. RESULTS: Lipid peroxidation increased as a function of radiation dose, from 45 to 600 Gv. Post-irradiation incubation of mitochondria under nitrogen decreased the response, while incubation under oxygen saturation enhanced it significantly. The presence of caffeine during radiation exposure inhibited lipid peroxidation significantly as a function of concentration, in the range of 5 microM to 4 mM. The inhibition was highest with 4 mM of caffeine. Under oxic conditions, inhibition at 1 mM was significantly more than under anoxia. Anoxia was either ineffective or marginally increased peroxidation in the presence of caffeine. A similar observation was obtained when membrane damage was assessed as protein oxidation. Radiation-induced depletion of protein thiols was greatly enhanced by oxygen saturation and this was completely prevented by caffeine. This compound also protected against the radiation-induced loss of the antioxidant glutathione and the enzyme superoxide dismutase. CONCLUSIONS: The results suggest that caffeine effectively protected membranes against the oxic component of damage but may not do so for the anoxic component.

Antioxidant properties of Asparagus racemosus against damage induced by gamma-radiation in rat liver mitochondria.

The possible antioxidant effects of crude extract and a purified aqueous fraction of Asparagus racemosus against membrane damage induced by the free radicals generated during gamma-radiation were examined in rat liver mitochondria. gamma-Radiation, in the dose range of 75-900 Gy, induced lipid peroxidation as assessed by the formation of thiobarbituric acid reactive substances (TBARS) and lipid hydroperoxides (LOOH). Using an effective dose of 450 Gy, antioxidant effects of A. racemosus extract were studied against oxidative damage in terms of protection against lipid peroxidation, protein oxidation, depletion of protein thiols and the levels of the antioxidant enzyme, superoxide dismutase. An active fraction consisting of polysaccharides (termed as P3) was effective even at a low concentration of 10 microg/ml. Both the crude extract as well as the P3 fraction significantly inhibited lipid peroxidation and protein oxidation. The antioxidant effect of P3 fraction was more pronounced against lipid peroxidation, as assessed by TBARS formation, while that of the crude extract was more effective in inhibiting protein oxidation. Both the crude extract and P3 fraction also partly protects against radiation-induced loss of protein thiols and inactivation of superoxide dismutase. The inhibitory effects of these active principles, at the concentration of 10 microg/ml, are comparable to that of the established antioxidants glutathione and ascorbic acid. Hence our results indicate that extracts from A. racemosus have potent antioxidant properties in vitro in mitochondrial membranes of rat liver.

Vanillin as an antioxidant in rat liver mitochondria: inhibition of protein oxidation and lipid peroxidation induced by photosensitization.

Using rat liver mitochondria, as model systems, we have examined the ability of the natural compound and the food-flavoring agent, vanillin to protect membranes against oxidative damage induced by photosensitization at concentrations normally used in food preparations. Vanillin, at a concentration of 2.5 mmol/L, has afforded significant protection against protein oxidation and lipid peroxidation in hepatic mitochondria induced by photosensitization with methylene blue plus light. The effect observed was both time- and concentration-dependent. The inhibitory effect is similar to ascorbic acid and the singlet oxygen quencher, diazabicyclo[2.2.2]octane (DABCO) but less effective than sodium azide and glutathione. Examination of possible mechanisms responsible for the observed protection, showed that vanillin has a significant ability to quench singlet oxygen (1O2), a reactive species responsible for damage induced during photosensitization by Type II mechanism. Hence, this flavoring compound, due to its antioxidant ability, may have potential to prevent oxidative damage to membranes in mammalian tissues and thereby the ensuing diseased states.

Chloroquine induced parkinsonism.

A case of parkinsonism is reported in a 5-years-old male child following prolonged use of chloroquine. The patient presented with reduced spontaneous movements and speech with an expressionless face and a parkinsonian gait but no tremors. His investigations including CT scan brain, CSF study and serum ceruloplasmin were normal. Chloroquine was discontinued and the patient was started on oral trihexyphenidyl. The patient showed gradual recovery and the drug was successfully withdrawn. The toxic manifestations were only transient and reversible.