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V Sanders

Publications and source records attributed to V Sanders.

24 records · Page 2Linked to original sources
PubMed1976

Acute toxicity of dimethylnitrosamine in the presence of inhibitors of DMN demethylase.

The LD50 of DMN was determined in groups of mice in the presence of inhibitors of DMN demethylase. Piperonyl butoxide, dibutylnitrosamine and nitrososarcosine had no effect on the acute toxicity of DMN. Diethylnitrosamine and DMN were markedly synergistic. All mice treated with 100 mg/kg diethylnitrosamine and 10.7 mg/kg DMN died. These results suggest that DMN demethylase may not be involved in the acute toxicity of DMN.

Animals↗
PubMed1976

Effects of piperonyl butoxide on dimethylnitrosamine metabolism and toxicity in Swiss mice.

The effects of piperonyl butoxide (PB) on the metabolism and toxicity of dimethylnitrosamine (DMN) in Swiss mice were determined. PB, at doses of 10 and 20 mg/kg, inhibited DMN demethylase 45 min after treatment by 18 and 37%. These inhibitory effects were marked 0.5 hr after PB (640 mg/kg) treatment and reached maximal effects at 2 hr when there was 55% inhibition of enzyme activity. The inhibition by PB continued for 24 hr where enzyme activity was suppressed by 35%. At 48 hr after treatment there was stimulation of enzyme activity. Enzyme kinetic determinations showed no change in Km but Vmax decreased from 129 to 49 mumol CH2O/min-g liver. PB (640 mg/kg) inhibited DMN (500 mg/kg; im) mutagenicity in the host-mediated assay, decreasing the mutant frequency by 42%. Paradoxically, PB (640 mg/kg) had no effect on the alkylation of nucleic acids or proteins in mouse liver, kidney, lung, or spleen. In addition, pretreatment with PB (640 mg/kg) had no effect on the LD50 of DMN.

Alkylation↗
PubMedDate not supplied

Radial keratotomy enhancements for residual myopia.

BACKGROUND: A systematic method of performing radial keratotomy enhancements in undercorrected eyes may increase accuracy and predictability and decrease the number of procedures required. A consecutive series of 372 radial keratotomy procedures, including 110 eyes that received enhancements under a systematic protocol, was evaluated. METHODS: Radial keratotomy was performed using the Reliable Keratotomy software, which uses the Thornton nomogram for primary radial keratotomy and provides a systematic method of performing enhancements. RESULTS: Ninety eyes (24%) received one enhancement, 16 eyes (4%) received two enhancements, and four eyes (1%) received three enhancements. Mean final spherical equivalent refraction was -0.44 D (-4.00 to +1.875 D, SD 0.86) for eyes that did not receive enhancements and -0.44 D (-2.50 to +1.00 D, SD 0.61) for eyes that had enhancements. Mean final residual myopia for the entire cohort was -0.44 D (-4.00 to +1.875 D, SD 0.79). At final examination, 242 (65%) eyes had a refraction within +/- 0.5 D and 298 (80%) within +/- 1.00. Among eyes that received enhancements, 75 (68%) had a refraction within +/- 0.50 D, and 89 (81%) within +/- 1.00 D; 40 eyes (36%) had uncorrected visual acuity of 20/20 or better, 99 eyes (90%) 20/40 or better, and all but one eye (99%) 20/80 or better at the final postoperative examination. Among the entire cohort, 130 eyes (35%) had uncorrected visual acuity of 20/20 or better, 312 (84%) had 20/40 or better, and 350 (94%) had 20/80 or better. No eye lost more than one line of spectacle-corrected visual acuity. CONCLUSION: A systematic approach to enhancement of undercorrected eyes after radial keratotomy, combined with accurate surgery, may reduce the need for multiple enhancements as well as the overcorrection rate, and provide improved uncorrected visual acuity.

Adolescent↗