Association of hypomagnesemia with inferior survival in a phase III, randomized study of cetuximab plus best supportive care versus best supportive care alone: NCIC CTG/AGITG CO.17.

BACKGROUND: Cetuximab-induced hypomagnesemia has been associated with improved clinical outcomes in advanced colorectal cancer (CRC). We explored this relationship from a randomized clinical trial of cetuximab plus best supportive care (BSC) versus BSC alone in patients with pretreated advanced CRC. PATIENTS AND METHODS: Day 28 hypomagnesemia grade (0 versus ≥1) and percent reduction (<20% versus ≥20%) of Mg from baseline was correlated with outcome. RESULTS: The median percentage Mg reduction at day 28 was 10% (-42.4% to 63.0%) for cetuximab (N = 260) versus 0% (-21.1% to 25%) for BSC (N = 251) [P < 0.0001]. Grade ≥1 hypomagnesemia and ≥20% reduction from baseline at day 28 were associated with worse overall survival (OS) [hazard ratio, HR 1.61 (95% CI 1.12-2.33), P = 0.01 and 2.08 (95% CI 1.32-3.29), P = 0.002, respectively] in multivariate analysis including grade of rash (0-1 versus 2+). Dyspnea (grade ≥3) was more common in patients with ≥20% versus < 20% Mg reduction (68% versus 45%; P = 0.02) and grade 3/4 anorexia were higher in patients with grade ≥1 hypomagnesemia (81% versus 63%; P = 0.02). CONCLUSIONS: In contrast to prior reports, cetuximab-induced hypomagnesemia was associated with poor OS, even after adjustment for grade of rash.

Effect of feeding polyunsaturated fatty acids with a low vitamin E diet on blood levels of tocopherol in men performing hard physical labor.

A diet made low in vitamin E by elimination of foods considered good sources of the vitamin was fed for 13 months to two groups of men engaged in strenuous labor. With a daily average dietary intake of about 9.4 mg of total tocopherols, a progressive decline in blood levels of tocopherol from 1.42 to 0.81 mg/100 ml was observed in the five control subjects. The test group of 30 men received a daily supplement of tocopherol-stripped safflower oil containing 88 g of polyunsaturated fatty acids and 2.3 mg of tocopherols. Average blood plasma levels of tocopherol in this group dropped rapidly from an initial value of 1.01 to about 0.5 mg/100 ml within 5 months and remained relatively stable thereafter. No muscular weakness or other physical symptoms were reported.

Stability of vitamin C (ascorbic acid) in tablets.

Stability of ascorbic acid (vitamin C) in various tablet formulations and the nature and extent of formation of decomposition products (dehydroascorbic acid, diketogulonic acid, and oxalic acid) were determined under normal conditions of storage and in simulated use tests. IR spectrophotometric, colorimetric, fluorometric, titrimetric, polarographic, and chromatographic methods were applied. Recent implications concerning the instability of ascorbic acid in tablets and the potentially harmful nature of the breakdown products are shown to be unfounded. Under normal storage conditions, commerical-type ascorbic acid tablets are stable for over 5 years (greater than 95% potency retention). The amounts of all three breakdown products formed under the various storage conditions constitute a small percentage of the ascorbic acid content and pose no dietary hazard. IR spectroscopy was inadequate as a quantitative method for evaluating ascorbic acid potency in tablet formulations. The official titration methods and TLC, colorimetric, and polarographic determinations correlate well and define accurately the stability of ascorbic acid in these dosage forms.

Spectrophotometric determination of sodium nitroprusside and its photodegradation products.

A specific spectrophotometric method of analysis for sodium nitroprusside was developed utilizing the molar absorptivity values at the maxima appearing in the electronic spectrum at 394 and 498 nm that may be attributed to metal d leading to pi* NO transitions. These measurements appear to be indicative of the unaltered nitroferricyanide complex. A reaction sequence is postulated for aqueous solutions of nitroprusside exposed to normal artificial light. Evidence suggests that one species in the sequence is nitroferricyanide in a higher energy state but with the nitrosyl moiety still present in the coordination sphere, which exhibits an increased molar absorptivity at 394 nm. The molar absorptivity at the 498-nm maximum remains unchanged. Corroborating polarographic data are presented.

Computing with words.

Computing with words is defined, in this paper, to be a symbolic generalization of fuzzy logic, which admits self-reference. It entails the randomization of declarative knowledge, which yields procedural knowledge. Such randomization can occur at two levels. First is termed weak randomization, which is essentially a domain-general pattern-matching operation. Second is termed strong randomization, which entails the application of one rule set to the semantics of another-possibly including itself. Strong randomization rests on top of weak randomization. Strong randomization is essentially a heuristic process. It is fully scalable, since it can in theory map out its own needed heuristics for evermore efficient search-including segmentation of the knowledge base. It is proven that strong learning must be knowledge-based, if effective. Computing with words does not preclude the use of predicate functions or procedural attachments. Also, the paradigm for computing with words does not directly compete with that for fuzzy logic. Rather, it serves to augment the utility of fuzzy logic through symbolic randomization. A countably infinite number of domain-specific logics or knowledge-based methods for randomization exist.

Improvement of faculty teaching performance in a department of obstetrics and gynecology by student evaluation.

The primary purpose of a faculty evaluation program is to upgrade the over-all quality of teaching and to identify the strengths and weaknesses of the individual teacher. Effective medical educators can thereby be suitably identified by objective and subjective criteria. Improvement of faculty teaching performance enhances student learning and can improve recruitment into our discipline.