Production and shelf stability of multiple-fortified quick-cooking rice as a complementary food.

Rice-based complementary foods normally contain inadequate amounts of several micronutrients, such as iron, calcium, and zinc. This study aimed at improving the quality of commercially produced rice-based complementary foods. The analysis centered on identifying a rice-based complementary food that is safe, stable, sensory acceptable, and economical in terms of fortificants (iron, calcium, zinc, thiamine, folate) and effectively packaged for industrial production and distribution. Product colors were mostly in green-yellow tone and slightly changed to more yellow during storage. Sensory acceptability was affected by changes in odor and rancidity but not in color. Rancidity scores were low in aluminum foil laminated plastic bags (ALU). Lipid oxidation significantly increased during storage, but at a slower rate when sodium citrate and ALU were used. Color differences of raw products were detected but not in the cooked ones. Mineral and vitamin losses during processing were 2% to 11% and 20% to 30%, respectively, but no losses were found during storage. FeSO(4)+ NaFeEDTA added with sodium citrate resulted in the most acceptable product for all packagings. The multiple-fortified quick-cooking rice (MFQCR) developed from this study could be a potentially useful tool for combating micronutrient deficiencies among infants and young children in the countries where rice is the staple food.

A survey of aflatoxin B1 and total aflatoxin contamination in baby food, peanut and corn products sold at retail in Indonesia analysed by ELISA and HPLC.

Aflatoxin contamination has been well known as a world-wide health-threatening problem in tropical countries including Indonesia. This research was undertaken to determine the degree of aflatoxin contamination in different Indonesian foodstuffs. A preliminary survey was carried out to evaluate the level of total aflatoxin (AfT) and aflatoxin B1 (AfB1) contamination of baby foods, peanut products, and corn products, which were purchased from traditional markets and supermarkets in Indonesia during the year 2001-2002. Eighty two peanut products, 12 baby foods products, and 11 corn products from different brands were analysed for AfT and AfB1 using the Enzyme-Linked Immunosorbent Assay (ELISA) method. The results indicate that, of the brands analysed, 35% of the peanut products were contaminated with aflatoxins at various levels (range 5 to 870 µg/kg). Peanut-chilli sauces had the highest percentage of AfT contamination 9/12 (75%), which was followed by traditional snacks 5/11 (45%), peanut butter 4/11 (40%), flour egg coated peanut 6/16 (37%), and peanut cake 3/10 (30%). Fried peanuts and roasted peanut were found to contain aflatoxin at relatively lower percentages of 9% and 8%, respectively. From the 12 analysed baby food samples, on the other hand, no sample was found to be contaminated with aflatoxins. Two of 11 samples (18%) of corn based products were contaminated with AfT, ranging between 5.8 and 12.4 µg/kg. Additionally, 30 selected samples in different concentration ranges were further analysed to verify the correlation between ELISA and HPLC techniques and results were compared.

Differential effect of buffer on the spin trapping of nitric oxide by iron chelates.

Nitric oxide synthase (NOS) generates nitric oxide (NO*) by the oxidation of l-arginine. Spin trapping in combination with electron paramagnetic resonance (EPR) spectroscopy using ferro-chelates is considered one of the best methods to detect NO* in real time and at its site of generation. The spin trapping of NO* from isolated NOS I oxidation of L-arginine by ferro-N-dithiocarboxysarcosine (Fe(DTCS)2) and ferro-N-methyl-d-glucamide dithiocarbamate (Fe(MGD)2) in different buffers was investigated. We detected NO-Fe(DTCS)2, a nitrosyl complex, resulting from the reaction of NO* and Fe(DTCS)2, in phosphate buffer. However, Hepes and Tris buffers did not allow formation of NO-Fe(DTCS)2. Instead, both of these buffers reacted with Fe2+, generating sparingly soluble complexes in the absence of molecular oxygen. Fe(DTCS)2 and Fe(MGD)2 were found to inhibit, to a small degree, NOS I activity with a greater effect observed with Fe(MGD)2. In contrast, Fe(MGD)2 was more efficient at spin trapping NO* from the lipopolysaccharide-activated macrophage cell line RAW264.7 than was Fe(DTCS)2. Data suggested that Fe(DTCS)2 and Fe(MGD)2 are efficient at spin trapping NO* but their maximal efficiency may be affected by experimental conditions.

Involvement of the perferryl complex of nitric oxide synthase in the catalysis of secondary free radical formation.

Neuronal nitric oxide synthase (NOS I) has been shown to generate nitric oxide (NO*) and superoxide (O(2)* during enzymatic cycling, and the ratio of each free radical is dependent upon the concentration of L-arginine. Using spin trapping and electron paramagnetic resonance spectroscopy, we detected alpha-hydroxyethyl radical (CH(3)*CHOH), produced during the NOS I metabolism of ethanol (EtOH). The generation of CH(3)*CHOH by NOS I was found to be Ca(2+)/calmodulin dependent. Superoxide dismutase prevented CH(3)*CHOH formation in the absence of L-arginine. However, in the presence of L-arginine, the production of CH(3)*CHOH was independent of O(2)* but dependent upon the concentration of L-arginine. Formation of CH(3)*CHOH was inhibited by substituting D-arginine for L-arginine, or inclusion of the NOS inhibitors N(G)-nitro-L-arginine methyl ester, N(G)-monomethyl-L-arginine and the heme blocker, sodium cyanide. The addition of potassium hydrogen persulfate to NOS I, generating the perferryl complex (NOS-[Fe(5+)=O](3+)) in the absence of oxygen and Ca(2+)/calmodulin, and EtOH resulted in the formation of CH(3)*CHOH. NOS I was found to produce the corresponding alpha-hydroxyalkyl radical from 1-propanol and 2-propanol, but not from 2-methyl-2-propanol. Data demonstrated that the perferryl complex of NOS I in the presence of L-arginine was responsible for catalyses of these secondary reactions.

Role of paraquat in the uncoupling of nitric oxide synthase.

Nitric oxide synthase (NOS) oxidizes L-arginine to NO(&z.ccirf;) and L-citrulline. Recent studies have shown that this enzyme can also generate O(2)(&z.ccirf;-) during its enzymatic cycling. Herein, we used spin trapping and electron paramagnetic resonance (EPR) spectroscopy to investigate the impact paraquat has on the transport of electrons through purified neuronal NOS (NOS I). In a concentration-dependent manner, ranging from 10-100 microM of paraquat, paraquat free radical was observed under anaerobic conditions. This demonstrates that NOS shunts electrons to paraquat, thereby uncoupling this enzyme. This resulted in enhanced production of O(2)(&z.ccirf;-) at the expense of NO(&z.ccirf;). Experiments demonstrated that the reductase domain is the site of paraquat-mediated uncoupling of NOS.

Stable expression of varied levels of inducible nitric oxide synthase in primary cultures of endothelial cells.

Nitric oxide (NO*), generated by nitric oxide synthase (NOS II) from immunostimulated cells during infection, plays an important role in host immune defense against microbial invasion. The impact of different rates of NO* production on host cell function has not been defined. Herein, we describe the development of a method to express varied levels of murine NOS II in bovine pulmonary artery endothelial cells. A retroviral vector (pMFGSNOS) encoding NOS II was used to transduce primary cultures of endothelial cells. Bovine endothelial cells were susceptible to this transduction and up to 18% of the cells expressed immunodetectable murine NOS II. The NOS II-transduced endothelial cells were cultured on the three-dimensional matrix, Gelfoam, for 8-10 days. Stable expression of NOS II was assessed by measuring nitrite accumulation in media every 2 days. By day 10, endothelial cells on Gelfoam were found to secrete NO* at a rate exceeding 1.0 microM/h/10(6) cells, concomitant with an enhanced level of NOS II activity. Argininosuccinate synthetase, a key enzyme in the metabolism of l-citrulline to l-arginine, increased as well, perhaps in response to dimunition of the intracellular arginine pool corresponding to the observed high output of NO*. In spite of the continuous flux of NO*, endothelial cell viability was not effected. This system provides the opportunity to assess the impact of different levels of sustained NO* production on endothelial cell physiology.

Spin trapping of nitric oxide by ferro-chelates: kinetic and in vivo pharmacokinetic studies.

Biologically generated nitric oxide appears to play a pivotal role in the control of a diverse series of physiologic functions. Iron-chelates and low-frequency EPR spectroscopy have been used to verify in vivo production of nitric oxide. The interpretation of in vivo identification of nitric oxide localized at the site of evolution in real time is complicated by the varied kinetics of secretion. The quantitative efficiency of the spectroscopic measurement, so important in understanding the physiology of nitric oxide, remains elusive. The development of a more stable iron-chelate will help better define nitric oxide physiology. In this report, we present data comparing the commonly used ferro-di(N-methyl-D-glucamine-dithiocarbamate) (Fe2+(MGD)2) and the novel chelate ferro-di(N-(dithiocarboxy)sarcosine) (Fe2+(DTCS)2) quantifying the in vitro and in vivo stability of the corresponding spin trapped adducts, NO-Fe(MGD)2 and NO-Fe(DTCS)2. Finally, very low frequency EPR spectroscopy has been used to evaluate the pharmacokinetics of NO-Fe(MGD)2 and NO-Fe(DTCS)2 in mice in real time.