Antisickling agents: Effects of carbamyl phosphate or cyanate on survival,erythrocytes, and leucocytes in the mouse

Equal mole doses of the anions of disodium carbamyl phosphate (carbamyl P) or sodium cyanate, antisickling agents, have been compared in C57B1 mice. Using 15 mice per group, two groups were given the equivalent ip dose of carbamyl P or cyanate anion (7 mmoles/kg/day) in a divided dose, in the morning and six hours later, for 17–18 days. The control group received sodium chloride (13.8 mmoles of Na⁺ or C1⁻/kg/day). Surviving mice per group were sodium chloride, 15/15; disodium carbamyl P, 14/15; and sodium cyanate, 0/15, all mice died by day 2. Surviving mice appeared normal throughout the study, and no abnormalities were seen at necropsy. The hematologic measurements were the same for sodium chloride or disodium carbamyl P, including hemoglobin, packed cell volume, erythrocyte counts, leucocyte counts, and differential counts. The mean hemoglobin carbamylation was 1.24 (±0.06 SE) moles of valine hydantoin/mole of hemoglobin tetramer in mice receiving disodium carbamyl P for 18 days, sufficient for antisickling activity. The enzymatic degradation of carbamyl P to NH₃, CO₂, and P_i was measured in serial blood samples in additional C57B1 and DBA/2J mice following ip injections of carbamyl P or cyanate. Both NH₃ and P_i increased immediately after giving carbamyl P, but no increase occurred after cyanate administration. Thus enzymatic degradation of carbamyl P occurs in vivo and appears to be an important detoxification mechanism. When equivalent mole doses of anion are administered, disodium carbamyl P is less toxic than sodium cyanate in mice.     

Xeromammographic automatic exposure termination

A method of automatic exposure termination (AET) for xeromammography has been devised, significantly reducing the rate of repeat exposures due to poor choice of manual exposure factors. AET images are of good quality and are reliably produced. The concept of AET is based on the existence of an optimal transmitted exposure to the selenium plate, which is easily determined experimentally. In routine clinical xeromammography, a repeat rate of 20% was eliminated by the use of AET.     

Effects of various periods of cold potassium cardioplegic arrest upon myocardial contractility and metabolism

A maximal “safe” period of cardioplegic arrest has not been documented. Twenty-five dogs were therefore subjected to 1, 2, and 3 hr of potassium cardioplegic arrest (Groups I, II, and III), using 200 ml at 20-min intervals of D₅ 0.2 NS with 20 mEq KCl and 6 mEq NaHCO₃/500 ml at 0–4°C. Results: Myocardial temperature decreased to 13°C after each cardioplegic infusion. Left ventricular pressure volume curves did not decrease significantly in Group I, but did in Group II, from 204 ± 20 mm Hg with 10-ml volume to 140 ± 8 (P < 0.03). Group III decreased from 117 ± 9 with 5-ml volume to 60 ± 3 (P < 0.0004), from 160 ± 11 with 10-ml volume to 108 ± 6 (P < 0.004), and from 181 ± 17 with 15-ml volume to 127 ± 9 (P < 0.03). Cardiac output was less in Group III than in Groups I and II 60 min after bypass [44 ± 10 vs 76 ± 8 ml/min/kg (P < 0.08)]. Myocardial ATP was significantly less in Group III than Group I 15 min after reperfusion and 60 min after bypass, being 2.25 ± 0.35 and 2.95 ± 0.81 vs 5.18 ± 0.85 and 5.68 ± 0.60 μmoles/g (P < 0.05). Myocardial lactate increased from 3.65 to 8.55 ± 0.81 μmoles/g at 60 min of cardioplegia, 9.36 ± 0.67 at 2 hr, and 12.01 ± 2.0 at 3 hr. Myocardial glycogen decreased through the cardioplegic period and remained depressed in Group III 30 min after bypass, being 488 ± 124 mg%, as compared to 901 ± 130 in Group I (P < 0.05). Conclusions: Hearts subjected to 1 and 2 hr of potassium cardioplegia showed relatively little hemodynamic or metabolic derangement, as compared to those subjected to 3 hr of cardioplegia.     

Breast neoplasms: duplex sonographic imaging as an adjunct in diagnosis

Sonographic breast imaging has been useful in the differentiation of cystic from solid masses. It has also been helpful in the characterization of palpable breast masses in the absence of corresponding abnormalities. The authors undertook a prospective study that incorporated pulsed Doppler analysis into sonographic real-time imaging of solid breast masses. Thirty-eight patients were examined. In 12 of the patients there were positive Doppler signals, while in 26 patients there were no Doppler signals. The 12 patients showing positive Doppler signals proved to have infiltrating ductal carcinoma, while the 26 patients with negative Doppler signals proved to have benign breast disorders. Pulsed Doppler analysis as a supplement to sonographic real-time imaging shows promise for the identification of breast carcinoma.