Development of oral liquid dosage forms of acetazolamide

Two oral liquid dosage forms of acetazolamide have been developed. Using the solubility profiles, polyethylene glycol 400 (7%, v/v) was used as the solubilizing agent and propylene glycol (53%, v/v) as the cosolvent to keep acetazolamide in solution. Because of the bitter taste of acetazolamide, sweetening agents (simple syrup, sorbitol solution, and artificial sweeteners) and flavors (raspberry, sweet, and menthol) were added to the final formulations. A buffer (either phosphate or citrate) solution was used to maintain a pH value of 4 (pH of maximum stability as reported earlier) to minimize hydrolysis. The final dosage forms were stable for at least 90 days at 37 degrees C (loss of potency of 5%). According to FDA guidelines, a tentative expiry date of 2 years at 25 degrees C is justifiable.     

Levels of metals in hair of young children as an indicator of environmental pollution

In 1982 the levels of lead (Pb), cadmium (Cd), vanadium (V), copper (Cu), and selenium (Se) were determined in hair of 231 four- to five-year-old children. The objective was to explore the feasibility of using metal-in-hair levels in groups of children as an indicator of environmental pollution. The study was carried out in four areas, which were assumed to differ in ambient pollution by metals. A questionnaire on personal data, socioeconomic status, intake of beverages, and life-style was completed by the parents. The metal-in-hair levels covered a large range. The variables pertaining to location together with sex, presence of a garden, and drinking of coffee and/or tea explained 32% of the variance of Pb, 24% of the variance of Cd, and 21% of the variance of V. The total variance explained by all measured questionnaire items was at best 38%. The location was the most important factor. Cu and Se levels did not differ between the locations.     

Haemangioma of the maxillary antrum

Haemangioma of the maxillary sinus is rare. Clinical diagnosis is of utmost importance for its operative treatment and prevention of hazards. A case is reported for its rarity and some unusual features.     

The virD operon of Agrobacterium tumefaciens Ti plasmid encodes a DNA-relaxing enzyme.

The virD locus of Agrobacterium tumefaciens Ti plasmid encodes functions necessary for endonucleolytic cleavage of transferred DNA (T-DNA) prior to its transfer to plant cells. For the overproduction of the VIRD proteins in Escherichia coli a tac-virD operon fusion was constructed. A significant increase in the accumulation of VIRD proteins was observed in a lon protease-deficient E. coli host. The presence of an overlapping open reading frame (ORF) upstream of the VIRD1 coding sequence had a negative effect on VIRD1 production. A preparation containing VIRD proteins catalyzes the conversion of supercoiled (form I) DNA to relaxed (form IV) DNA. This activity is similar to that of a DNA topoisomerase. The relaxation activity lacks DNA sequence specificity, requires magnesium ion, and has no requirement for an energy source. Studies with plasmids that had lost defined DNA segments encompassing various virD coding regions showed that VIRD1 is the DNA-relaxing enzyme. In a density gradient centrifugation experiment, the DNA-relaxing activity sedimented as a 21-kDa polypeptide. Earlier studies of Jayaswal et al. [Jayaswal, R., Veluthambi, K., Gelvin, S. & Slightom, J. (1987) (J. Bacteriol. 169, 5035-5045] have shown that in E. coli VIRD2 alone is not sufficient for endonucleolytic cleavage of T-DNA and requires VIRD1 for its activity.     

Studies on Relative Toxicities of Six Insecticides on Epigeic Earthworm, Perionyx excavatus

The 96 h LC₅₀ values of six insecticides were determined on a non-target epigeic earthworm Perionyx excavatus under laboratory conditions. Cypermethrin was found most toxic to P. excavatus (LC₅₀-0.008 mg/kg), followed by endosulfan (LC₅₀-0.03 mg/kg), carbaryl (LC₅₀-6.07 mg/kg), chlorpyrifos (LC₅₀-7.3 mg/kg), aldicarb (LC₅₀-10.63 mg/kg) and monocrotophos (LC₅₀-13.04 mg/kg). When these LC₅₀ values were compared with their respective recommended agricultural doses, aldicarb and carbaryl appeared more dangerous than other pesticides because of their lower LC₅₀ values than their respective recommended agricultural dose. Mean lethal time to cause 50% mortality at recommended agricultural dose (LT₅₀) also indicated that aldicarb achieved the fastest LT₅₀ (26 h) followed by endosulfan (38 h) and carbaryl (44 h) indicating the danger of these pesticides to P. excavatus.     

Modulation by dietary vitamin E of I-compounds (putative indigenous DNA modifications) in rat liver and kidney

I(indigenous)-compounds are age-related, carcinogen adduct-like, putative indigenous DNA modifications detectable by 32P-postlabeling assay in untreated animals. To investigate the origins of these DNA derivatives, we examined the effects of dietary vitamin E, a natural antioxidant, on I-compounds of rat liver and kidney DNA. Weanling female Sprague-Dawley rats were fed Draper's diets containing 0, 100, 1000, or 10,000 mg/kg alpha-tocopheryl acetate for 6 mo. The DNA from four individual rats of each group was analyzed by a nuclease P1-enhanced version of the 32P-postlabeling assay for DNA adducts. The amount of vitamin E in the liver was measured by high performance liquid chromatography. Rats fed vitamin E-deficient diet (0 mg/kg) showed identical profiles and similar levels of I-compounds as those fed the 100 mg/kg diet. Most I-spots were significantly intensified and one tissue-specific extra spot was found in both liver and kidney DNA of rats fed the 1000 or 10,000 mg/kg vitamin E diet. However, one of the five major I-spots detected in the kidney was weaker in the 1000 and 10,000 mg/kg groups than in the 0 and 100 mg/kg groups. These results show that formation of most I-compounds was not affected by vitamin E-deficient diet, and that long-term feeding of diet containing high levels of vitamin E may cause metabolic alterations leading to an increased formation of DNA-reactive (potentially mutagenic or carcinogenic) electrophiles.     

Design of a bifunctional fusion protein for ovarian cancer drug delivery: single-chain anti-CA125 core-streptavidin fusion protein.

We have developed a universal ovarian cancer cell targeting vehicle that can deliver biotinylated therapeutic drugs. A single-chain antibody variable domain (scFv) that recognizes the CA125 antigen of ovarian cancer cells was fused with a core-streptavidin domain (core-streptavidin-VL-VH and VL-VH-core-streptavidin orientations) using recombinant DNA technology and then expressed in Escherichia coli using the T7 expression system. The bifunctional fusion protein (bfFp) was expressed in a shaker flask culture, extracted from the periplasmic soluble protein, and affinity purified using an IMAC column. The two distinct activities (biotin binding and anti-CA125) of the bfFp were demonstrated using ELISA, Western blot and confocal laser-scanning microscopy (CLSM). The ELISA method utilized human NIH OVCAR-3 cells along with biotinylated bovine serum albumin (B-BSA) or biotinylated liposomes, whereas, the Western blot involved probing with B-BSA. The CLSM study has shown specificity in binding to the OVCAR-3 cell-line. ELISA and Western blot studies have confirmed the bifunctional activity and specificity. In the presence of bfFp, there was enhanced binding of biotinylated antigen and liposome to OVCAR-3 cells. In contrast, the control EMT6 cells, which do not express the CA125 antigen, showed minimal binding of the bfFp. Consequently, bfFp based targeting of biotinylated therapeutic drugs, proteins, liposomes, or nanoparticles could be an alternative, convenient method to deliver effective therapy to ovarian cancer patients. Peritoneal infusion of the bfFp-therapeutic complex could also be effective in locally targeting the most common site of metastatic spread.