Voltammetric Quality Control of Bioactive Additives: Determination of B<Subscript>1</Subscript>, B<Subscript>2</Subscript>, C,E Vitamins and Quercetin

Rapid voltammetric procedures for the determination of water-soluble vitamins C, B₁, and B₂, fat-soluble vitamin E (α-tocopherol acetate), and quercetin in bioactive food additives have been developed. The systematic error (i.e., correctness) of the proposed procedures was evaluated using certified reference materials and the additive recovery tests, which gave the following limiting metrological characteristics: relative error, 25 %; reproducibility, 28 %; convergence, 22 %. The full analysis time (with sample preparation) did not exceed 2 hours. Voltammetric determinations under optimum conditions can be performed in the automated regime controlled by a computer according to the specially developed software.__________Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 39, No. 3, pp. 54 – 56, March, 2005.     

Inhibitory effect of phospholipase A2 isolated from Crotalus durissus terrificus venom on macrophage function

Recent work demonstrated that crotoxin, the main toxin of Crotalus durissus terrificus venom, inhibits macrophage spreading and phagocytic activities. The crotoxin molecule is composed of two subunits, an acidic non-toxic and non-enzymatic polypeptide named crotapotin and a weakly toxic basic phospholipase A₂ (PLA₂). In the present work, the active subunit responsible for the inhibitory effect of crotoxin on macrophage function was investigated. Peritoneal macrophages harvested from naive rats were used. Crotapotin (2.12, 3.75, or 8.37 nM/ml), added for 2 h to the medium of peritoneal cell incubation, did not modify the spreading and phagocytic activities of these cells. On the other hand, the PLA₂ (1.43, 2.86, or 6.43 nM/ml) subunit caused a significant reduction (30, 33, and 35%, respectively) of the spreading activity. The PLA₂ also inhibited the phagocytosis of opsonised zymosan, opsonised sheep erythrocytes, and Candida albicans, indicating that this inhibitory effect is not dependent on the type of receptor involved in the phagocytosis process. The inhibitory effect of PLA₂ was not due to loss of cell membrane integrity, since macrophage viability was higher than 95%. These findings indicate that the inhibitory effect of crotoxin on macrophage spreading and phagocytic activities is caused by the phospholipase A₂ subunit.     

Comparison of assays for determination of peptide content for lyophilized thymalfasin*

Abstract: Precise determination of the peptide content in drug substance samples depends highly upon the particular peptide compound and methodology used. Four independent methods were evaluated and compared to determine which would produce the best experimental precision for analysis of thymalfasin (thymosin α‐1). Four different methods were evaluated including elemental analysis (CHN), quantitative amino acid analysis (AAA), high‐performance liquid chromatography (HPLC), and Kjeldahl. This study demonstrates that the AAA method is highly variable in one laboratory while quite precise in another laboratory. Similarly, HPLC results depended on the laboratory conducting the study with more precise values obtained under cGMP. On the contrary, the CHN method yielded highly precise [i.e. <2% coefficient of variation (CV)] values. As precise knowledge of protein content is fundamental for the compounding of final pharmaceutical product of a specific potency, the CHN analysis is recommended for peptide content determination of the drug substance thymalfasin.     

Asthma inhalers and subsurface enamel demineralisation: an in situ pilot study.

AIM: The purpose of this pilot study was to identify the subsurface enamel demineralising potential of two possible acidogenic lactose-based powders and their corresponding generic pump inhalers. METHODS: Ten healthy non-asthmatic adults participated in a 5- leg randomised crossover study including a 10% sucrose control. A twice-daily 400 microg dose of inhaler was applied in vitro to a demineralised enamel slab on the buccal flange of a mandibular removable appliance before in situ placement for 14 days each. Lesion parameters were determined using transverse microradiography and digitised image analysis. RESULTS: Minimal demineralisation occurred with sucrose, both pump and one powder inhaler. The remaining powder was associated with remineralisation (p = 0.29). Overall, mean lesion depth increased (p = 0.12). CONCLUSION: Asthma inhalers failed to demonstrate a significant acidogenic/cariogenic effect.     

Toll-like receptor signaling inhibits structural development of the distal fetal mouse lung.

We tested the hypothesis that innate immune signaling in utero could disrupt the structural development of the fetal lung, contributing to the pathogenesis of bronchopulmonary dysplasia. Injection of Escherichia coli lipopolysaccharide (LPS) into the amniotic fluid of E15 BALB/cJ mice increased the luminal volume density of fetal mouse lungs at embryonic day (E) 17 and E18. LPS also increased luminal volume and decreased distal lung branching in fetal mouse lung explants. This effect required NF-kappaB activation and functional Toll-Like Receptor 4. Airway branching may require fibronectin-dependent epithelial-mesenchymal interactions, representing a potential target for innate immune signaling. Anti-fibronectin antibodies and LPS both blocked distal lung branching. By immunofluorescence, fibronectin localized to the clefts between newly formed airways but was restricted to peripheral mesenchymal cells in LPS-exposed explants. These data suggest that LPS may alter the expression pattern of mesenchymal fibronectin, potentially disrupting epithelial-mesenchymal interactions and inhibiting distal airway branching and alveolarization. This mechanism may link innate immune signaling with defects in structural development of the fetal lung.     

Olfactory neuroblastoma mimicking primary intracranial neoplasm

A case of esthesioneuroblastoma with an unusual clinical and radiographic presentation is reported. The presenting symptoms as well as the computed tomographic examination were compatible with a primary intracranial mass.     

Susceptibility of upper-genital tract isolates from women with pelvic inflammatory disease to ampicillin, cefpodoxime, metronidazole, and doxycycline

The antibiotics that are recommended for treatment of pelvic inflammatory disease (PID) in the outpatient setting are efficacious against Neisseria gonorrhoeae and Chlamydia trachomatis. The susceptibility of non-sexually transmitted pathogens to these agents has not been well studied. The mean inhibitory concentrations of ampicillin, cefpodoxime, metronidazole, and doxycycline were determined for 137 upper-genital tract isolates from 84 women with confirmed PID. Antibiotic resistance was noted in 16%, 9%, 93%, and 72% of the facultative and 0%, 11%, 10%, and 56% of the anaerobic bacteria when tested against ampicillin, cefpodoxime, metronidazole, and doxycycline, respectively. The authors conclude that doxycycline is limited to coverage of Chlamydia and that a single dose of another antibiotic may not be adequate to eradicate the non-sexually transmitted disease pathogens from the upper-genital tract. Additional clinical and microbiologic studies are needed to determine whether the current outpatient antibiotic regimens provide optimal coverage for the non-sexually transmitted pathogens that are associated with PID.     

Radiographic appearance of artificially prepared periapical lesions confined to cancellous bone

Summary. Twenty artificial periapical lesions confined to cancellous bone were prepared at the apices of first and second mandibular molars of human cadavers. The lesions emphasized removal of the lamina dura and preparation of a 'halo' lesion surrounding the root apex, plus the addition of a simulated sclerotic border. Radiographs taken before and after creation of the lesions were scored by three examiners for detectable lesions Cross-sections of the lesions were assessed for the extent of bone destruction. Periapical lesions confined to cancellous bone were detected in 80 per cent of cases, and the presence of a sclerotic border tended to enhance visualization, although not in all cases. Intentional cortical involvement also improved detection of lesions. The anatomical features of the periapical area appear to promote the visualization of lesions which might not be detected in other locations.