Liquid Chromatographic Method for Determining Capsaicinoids in Capsicums and Their Extractives: Collaborative Study

Sixteen laboratories participated in an AOAC–American Spice Trade Association (ASTA) collaborative study of a liquid chromatographic (LC) method for determining capsaicinoids in capsicums and their extractives. Capsicums are extracted with ethanol by refluxing and then filtered. Capsaicinoids in the filtrate are separated by re- versed-phase LC and detected spectrophotometri� cally with external standard quantitation. Participants analyzed 6 ground capsicum and 3 oleoresin products as 12 samples from a mixed scheme of blind duplicates and Youden matched pairs. Average repeatability and reproducibility standard deviations (sr and sR, respectively) and average relative standard deviations (RSDr and RSDR, respectively) for ground red pepper were as follows: sr, 610 Scoville heat units (SHU); sR, 1730 SHU; RSDr, 1.7%; RSDR, 4.9%. For ground chili peppers, the values were sr, 60 SHU; sR, 160 SHU; RSDr, 4.0%; RSDR, 10.6%. For oleoresin red pepper, the averages were sr, 46820 SHU; sR, 54990 SHU; RSDr, 8.5%; RSDR, 11.2%. The LC method has been adopted first action by AOAC INTERNATIONAL.

Efficient in vivo catheter-based pericardial gene transfer mediated by adenoviral vectors

Adenoviral vectors are promising agents for a number of in vivo gene therapy applications including diseases of the heart and coronary vessels. Efficient intravascular gene transfer to specific sites has been achieved in occluded vessels, but otherwise is hampered by the effect of blood flow on localized vector uptake in the vessel wall. An alternative delivery approach to coronary arteries is the expression of diffusible gene products into the pericardial space surrounding the heart and coronary arteries. However, in vivo pericardial access is comparatively difficult and has been limited to surgical approaches. We hypothesized that efficient adenovirus-mediated gene expression in pericardial lining mesothelium could be achieved by transmyocardial vector delivery to the pericardium. To evaluate this concept, a hollow, helical-tipped penetrating catheter was used to deliver vector-containing fluid directly into the intrapericardial space. The catheter was introduced percutaneously in anesthetized mongrel dogs, advanced into the right ventricle, and the tip passed through the apical right ventricular myocardium under direct radiographic visualization until the open end of the catheter tip resided in the intrapericardial space. Adenoviral vectors expressing either nuclear-localizing beta-galactosidase, cytoplasmic luciferase, or secreted human alpha 1AT reporters (Av1nBg, Av1Lu, or Av1Aa, respectively) were instilled through the catheter into the intrapericardial space. Three days later the animals were sacrificed and reporter gene expression was evaluated in pericardium, epicardium, and multiple other tissues. In animals receiving Av1nBg, beta-galactosidase activity was evident in most of the pericardial lining endothelium, up to 100% in many areas. In animals receiving Av1Lu, luciferase reporter activity was abundant in pericardial tissues, but near-background levels were observed in other organs. In animals receiving Av1Aa, human alpha 1AT was abundant (16-29 mg/ml) in pericardial fluid, but was undetectable in serum. All animals tolerated the procedure well with no electrocardiographic changes and no clinical sequelae. These observations demonstrate highly efficient adenovirus vector delivery and gene transfer and expression in the pericardium and support the feasibility of localized gene therapy via catheter-based pericardial approaches. We suggest that the pericardial sac may serve as a sustained-release protein delivery system for the generation of desired gene products or their metabolites for diffusion into the epicardial region.

Biochemical and antitumor activity of trimidox, a new inhibitor of ribonucleotide reductase

Trimidox (3,4,5-trihydroxybenzamidoxime), a newly synthesized analog of didox (N,3,4-trihydroxybenzamide) reduced the activity of ribonucleotide reductase (EC 1.17.4.1) in extracts of L1210 cells by 50% (50% growth-inhibitory concentration, IC50) at 5 microM, whereas hydroxyurea, the only ribonucleotide reductase inhibitor in clinical use, exhibited an IC50 of 500 microM. Ribonucleotide reductase activity was also measured in situ by incubating L1210 cells for 24 h with trimidox at 7.5 microM, a concentration that inhibits cell proliferation by 50% (IC50) or at 100 microM for 2 h; these concentrations resulted in a decrease in enzyme activity to 22% and 50% of the control value, respectively. Trimidox and hydroxyurea were cytotoxic to L1210 cells with IC50 values of 7.5 and 50 microM, respectively. Versus ribonucleotide reductase, trimidox and hydroxyurea yielded IC50 values of 12 and 87 microM, respectively. A dose-dependent increase in life span was observed in mice bearing intraperitoneally transplanted L1210 tumors. Trimidox treatment (200 mg/kg; q1dx9) significantly increased the life span of mice bearing L1210 leukemia (by 82% in male mice and 112% in female mice). The anti-tumor activity appeared more pronounced in female mice than in male mice. Viewed in concert, these findings suggest that trimidox is a new and potent inhibitor of ribonucleotide reductase and that it is a promising candidate for the chemotherapy of cancer in humans.

Outcome after very early treatment of dense congenital unilateral cataract

PURPOSE

To evaluate whether very early treatment for congenital unilateral cataract results in better long-term functional outcomes, grating acuity, contrast sensitivity, recognition acuity, and random-dot stereoacuity were evaluated in two groups of children.

METHODS

Grating acuity and contrast sensitivity data were obtained with standard forced-choice protocols. Stereoacuity data were obtained both in a forced-choice laboratory protocol and by the Randot test.

RESULTS

Immediately after treatment, both the very early (1 to 6 weeks; n = 8) and early (2 to 8 months; n = 6) treatment groups showed a 0.3 log unit grating acuity deficit in the aphakic eye. Grating acuity in the early group showed some improvement with age but reached a plateau of 0.75 logMAR at 18 to 24 months; the very early group showed more improvement and reached a plateau of 0.22 logMAR at 37 to 48 months. At 5 to 8 years of age, aphakic eyes of the very early group had significantly better contrast sensitivity and recognition acuity than the aphakic eyes of the early group. Overall, grating acuity deficits during years 2 through 5 were significantly correlated with contrast sensitivity and recognition acuity outcomes measured at 5 to 8 years of age. No deficits in grating acuity, contrast sensitivity, or recognition acuity were found for phakic fellow eyes in either group. Three children in the very early treatment group (37.5%) were orthotropic and demonstrated gross random-dot stereopsis; one child in the early group was orthotropic but none of these children demonstrated random-dot stereopsis.

CONCLUSIONS

These results suggest that treatment initiated at 1 to 6 weeks of age maximizes the opportunity for normal or near-normal visual development of a congenitally cataractous eye with little or no risk to the phakic fellow eye.

Effect of tetranitromethane on the biological activities of botulinum neurotoxin types A, B and E

Botulinum neurotoxin serotypes A, B and E were modified at pH 7.9 with tetranitromethane, a reagent highly specific for tyrosine residues. The type B and E neurotoxins were completely detoxified without significant damage to their serological activities. Under similar modification conditions, the type A neurotoxin was incompletely detoxified with some alteration in its serological reactivity. Modification of only tyrosine residues to nitrotyrosine was evident from amino acid analysis of the acid hydrolysates of the modified proteins. The completely detoxified type B and E neurotoxins, used as toxoid, elicited antibodies in rabbits. The antisera precipitated and neutralized the homologous neurotoxin. The two toxoids, type B and E, were prepared with greater than 99% pure neurotoxins as tested by sodium dodecyl sulfate-polyacrylamide gel electrophoresis whereas the traditional toxoids produced with formaldehyde are very crude preparations of the neurotoxin (approximately 90% impure). Chemical modification using tetranitromethane is more specific than products that form during approximately 7 days of reaction between a protein and formaldehyde. The toxoids produced with tetranitromethane may be considered second-generation toxoids, compared with the first-generation toxoids (crude preparation of neurotoxins detoxified with formaldehyde).