Contribution of wood smoke to in vivo formation of N-nitrosothiazolidine-4-carboxylic acid: initial studies

The effect of administering liquid smoke or smoked food products to rats on in vivo formation of N-nitrosamino acids was investigated. Rats treated by gavage with either cysteine, formaldehyde or nitrite excreted urine containing no detectable levels of N-nitrosothiazolidine-4-carboxylic acid (NTCA). All three precursor compounds were required for NTCA formation. Two liquid smokes, when administered to rats in combination with cysteine and nitrite also produced measurable quantities of NTCA. Ascorbate inhibited in vivo formation of NTCA by approximately 90% when given to rats simultaneously with cysteine, formaldehyde, and nitrite. alpha-Tocopherol was much less effective than ascorbate in blocking NTCA formation. When smoked bacon, smoked Swiss cheese, and chicken barbecued with a sauce containing smoke flavouring were fed to rats along with nitrate, NTCA was again detected in the urine.     

Effects of malnutrition on the erythrocyte fatty acid composition and plasma vitamin E levels of Pakistani children

Abstract Erythrocyte fatty acids and plasma vitamin E concentrations were determined in 47 grade 2 and 21 grade 3 malnourished Pakistani children (ages 4–56 months). Data were compared with those of 26 age- and sex-matched apparently healthy controls. Evaluation with three statistical approaches revealed that both grade 2 and grade 3 malnourished children had decreased erythrocyte ω6 fatty acids and to a lesser extent decreased ω3 fatty acids. These decreases were compensated for by increased ω9 fatty acids. The patients tended to have lower plasma vitamin E concentrations. We conclude that malnourished Pakistani children have low essential fatty acid status, notably those of the ω6 series. The combination of low erythrocyte 22:6ω3 and a low 22:5ω6/22:4ω6 ratio in grade 2 patients suggests low Δ4-desaturation activity, which may be due to impaired peroxisomal β-oxidation.     

Hormone receptors in renal cell carcinoma

Summary We have performed 23 estrogen and 24 progesterone receptor assays on tumor specimens from 26 patients with renal cancer, ten of whom subsequently received hormonal therapy for metastatic disease. Only one of these specimens contained measurable estrogen receptor levels, three contained low, but measurable progesterone receptor levels, and the remaining specimens contained no measurable estrogen or progesterone receptors. None of ten patients with metastases showed evidence of an objective response to hormonal therapy. Our data suggest that few, if any, renal cancers have high titers of estrogen or progesterone receptors, and that those patients whose tumors have low receptor titers are unlikely to respond to hormonal therapy.     

Effect of some organic acid salts of tris(hydroxymethyl)aminomethane in the incubation step on plasma renin activity

The tris(hydroxymethyl)aminomethane salts of the organic acids acetylsalicylic, phenoxyacetic, salicylic, benzoic, acetic, and maleic were used to buffer the pH of plasma between 7.4 and 7.7 in a 1 h incubation step of the procedure for the determination of plasma renin activity. When compared to the plasma renin activity determined with tris(hydroxymethyl)aminomethane hydrochloride or with no buffer, it was found that all of the tris(hydroxymethyl)aminomethane salts of the organic acids studied produced a statistically significant increase in plasma renin activity except the salt of acetic acid when compared to tris(hydroxymethyl)aminomethane hydrochloride. In comparison to tris(hydroxymethyl)aminomethane hydrochloride and unbuffered plasma the organic acid salts and their mean percent difference in plasma renin activity are as follows: tris(hydroxymethyl)aminomethane phenoxyacetate (101%, 105%); tris(hydroxymethyl)aminomethane acetylsalicylate (79%, 115%); tris(hydroxymethyl)aminomethane benzoate (70%, 107%); tris(hydroxymethyl)aminomethane salicylate (64%, 70%); tris(hydroxymethyl)aminomethane maleate (32%, 60%); and tris(hydroxymethyl)aminomethane acetate (?1.6%, 43%).     

Macrophage Cytostasis and T and B Cell Blastogenic Transformation in Mice Treated with Nystatin

Treatment of normal BALB/c mice with nystatin, an amphoteric polyene, activated macrophages to become tumoricidal for MBL-2 lymphoblastic leukemia target cells while augmenting the in vitro blastogenic response of splenic lymphocytes to B and T cell mitogens. These responses were both shown to be highly dose dependent and occurred 6 days following the intraperitoneal injection of nystatin into normal mice. Macrophages from untreated mice did not show similar activity. The significance of these observations and the potential use of nystatin as a pharmacologic agent is discussed.     

Comparison of radionuclide and contrast ventriculography for detection and quantitation of regions of myocardial ischemia in dogs.

Radionuclide and contrast ventriculography were evaluated for their ability to estimate myocardial ischemia. In 14 closed-chest, sedated dogs, a small and larger region of ischemia were produced by inflating balloon occluders on the left anterior descending coronary artery. The systemic arterial pressure, atrial-paced heart rate, global ejection fraction by radionuclide and contrast ventriculography, regional wall-motion abnormalities (as the percentage of abnormally contracting segments), and regional myocardial blood flow (using the microsphere technique) were measured during an initial control period, two separate ischemic periods, and a final control period. The regional ischemic weights based on myocardial blood flow ranged from 0 to 38.5 g and were grouped as zero, small (range 0 to less than 10 g, mean 3.40 g), and large regions of ischemia (greater than 10 g, mean 24.8 g). Regional wall-motion abnormalities were sensitive qualitative indicators of ischemia. Receiver operating characteristic analysis showed that both ventriculographic methods were highly sensitive, specific, and accurate for detecting regional ischemia. Contrast ventriculography was slightly superior for detecting small regions less than 4 g, but the methods were equal for regions greater than 4 g. The arterial pressure and heart rate were unchanged during ischemia. For small regions of ischemia, the global ejection fraction did not fall using either the contrast or radionuclide technique, but it fell significantly when large regions were produced. There was a quantitative relationship between the percentage of abnormally contracting segments and the grams of myocardial ischemia (for radionuclide ventriculography, r = 0.65, P = 0.003, and for contrast ventriculography, r = 0.75, P less than 0.001), but for many small regions of ischemia, wall-motion changes were greater than anticipated, suggesting hypofunction of the continguous normal tissue. This study demonstrated that both radionuclide and contrast ventriculography were quite sensitive and specific for detecting measured amounts of regional ischemia. The functional changes resulting from ischemia are quantitatively related to the extent of regional ischemia, small areas resulting in regional wall motion abnormalities, and large areas producing both reduced global ejection fraction and wall motion changes.