Determination of the stable isotope of nitrite flux in the blood of mice by gas chromatography-mass spectrometry with selected ion monitoring

A simple and reliable method for the determination of the stable isotope of nitrite (15NO2) flux in the blood of mice is described. It is based on the reaction of 15NO2 with 1-hydrazinophthalazine in acidic solution to form [15N]tetrazolophthalazine, a stable compound which can be extracted with an organic solvent and then determined by gas chromatography-mass spectrometry with selected ion monitoring using the pentafluorobenzoyl ester of 2,4-dinitro-6-sec.-butylphenol as an internal standard. Amounts of 0.2-10 micrograms of 15NO2 can be determined. The detection limit of 15NO2 was 0.1 microgram/ml. This is a specific method for 15NO2. The procedure for determining 15NO2 in the blood of mice involves extraction with solvent, followed by further clean-up by alumina column chromatography; the detection limit is 0.05 microgram. With the new technique we were able to perform a metabolic fate study of nitrite in the blood of mice following a single oral dose of 15NO2 or the stable isotope of nitrate (15NO3).

[Surgical treatment of abdominal aortic aneurysm in the elderly]

Because of the increasing longevity of man, more elderly patients of abdominal aortic aneurysm are being considered for surgical treatment. It is the purpose of this report to provide the data based on analysis of 23 patients, 70 years of age or older, compared with 26 patients, under 70 years of age, seen at our institution during the last 8-year period so that a rational decision can be made regarding abdominal aortic aneurysm operation in the elderly. Operation in the elderly group (n = 17) and in the younger group (n = 25) was associated with 5.9% and 4.0% operative mortality, respectively. Calculated actuarial survival at 5 years was 69.2% for operated elderly, 0% for non-operated elderly and 57.8% for operated younger groups. Rupture of abdominal aortic aneurysm was a high cause of death (40%) in the non-operated elderly group. Considering operative mortality, long-term survival and natural history of unoperated abdominal aortic aneurysms, our conclusion is that regardless of age of patients and size of aneurysms, operation should be recommended as a general rule for the elderly as for the younger patients.

Gas-liquid chromatographic determination of trace amounts of nitrite in egg, egg white, and egg yolk

A simple, sensitive, and practical method is described for determination of nitrite in egg, egg white, and egg yolk. Egg is deproteinized by adding a mixture of ammonium thiocyanate, mercuric chloride, and zinc acetate, and centrifuged. Nitrite in the supernate is converted to tetrazolophthalazine by reaction with hydralazine in acidic solution and then determined by gas-liquid chromatography with an electron-capture detector (GLC-ECD) and a column of OV-225 on Chromosorb W(HP). Nitrite concentrations from 5 to 50 ng/mL are calculated from peak height; the detection limit is 3 ng/mL extract. Recoveries from eggs, egg whites, and egg yolks ranged from 91.7 to 98.0%. The mean nitrite concentration in 50 egg samples was 0.04 ppm (0.01-0.11 ppm) with a detection limit of 4 ng nitrite/g.

Coarctation of the aorta in early infancy. Left ventricular outflow tract obstruction and its clinical implications

In order to clarify the clinical significance of left ventricular outflow tract obstruction, 11 infants with coarctation of the aorta and ventricular septal defect were subjected to cineangiography (or autopsy) analysis. Three infants without left ventricular outflow tract obstruction were salvaged by aortoplasty using a subclavian flap or a Dacron patch with concomitant pulmonary artery banding. The remaining 8 infants died surgically or nonsurgically, and were confirmed retrospectively to have had left ventricular outflow tract obstruction. It seems worthwhile to stress that the presence of an abnormal muscle bundle in the left ventricle can be demonstrated angiographically, especially by the axial technique. From our present study, though the number of cases examined is limited, we have an impression that left ventricular outflow tract obstruction may be a determining factor with regard to the appropriateness of pulmonary artery banding in the two-stage operation for infantile coarctation associated with a large ventricular septal defect.

Direct communication of the right pulmonary artery with the left atrium in an infant

An 8-month-old Japanese girl with cyanosis and evidence of a round shadow connected with the right cardiac border on the chest X-ray film was diagnosed as a case of direct communication of the right pulmonary artery with the left atrium (RPA-LA communication) following cardiac catheterization and angiocardiography. She had a history of transient congestive heart failure in the early neonatal period. A secundum atrial septal defect and a two-lobed right lung were also present. The patient became asymptomatic after a successful ligation of the anomalous connecting vessel.

Ga-67 scan in patients with intrathoracic esophageal carcinoma planned for surgery

The authors evaluated Ga-67 scan in 68 patients with intrathoracic esophageal carcinoma initially planned for surgery. Of these, 59 patients were staged pathologically or surgically; their Ga-67 scan results correctly predicted the presence of extraesophageal spread and lymph node metastases. Of 38 clinical Stage II patients, 15 (39%) could be Stage III by the results of Ga-67 scan. However, two of four clinical Stage I patients (50%) and 35 of 38 clinical Stage II patients (92%) were eventually pathologic or surgical Stage III. This high conversion rate and the high incidence of Stage III in esophageal carcinoma patients may not justify routine use of Ga-67 scan only for staging. Ga-67 scan, however, was useful for planning radiotherapy, because missing extraesophageal extension or gross metastases from the radiation fields were detected in six patients of 51 so treated. Ga-67 scan has its value in some patients with intrathoracic esophageal carcinoma.

Isolation of soluble immunosuppressive substance(s) from Ehrlich ascites tumor cell nuclei

A potent immunosuppressive principle was isolated in a soluble form from the nuclei of Ehrlich ascites tumor cells. DNA-free preparation, obtained from the purified nuclei by homogenizing in 2M NaCl-5M urea solution and removing the dissociated DNA with LaCl3-precipitation, revealed strong activity to suppress the development of helper thymus-derived lymphocyte activity in mice. Moreover, almost all of the immunosuppressive activity originally found in the nuclear residue fraction after extraction with sodium citrate solution was recovered in 0.25 N HCl extract which mainly contains proteins. The nuclear components of tumor cells were also detected in the body fluid of tumor-bearing animals, as examined by the reactivity with a rabbit antiserum specific for some nuclear component of Ehrlich tumor cells. These results suggest that the immunosuppressive principle in the nuclei of Ehrlich tumor cells is a histone-like substance, and liberated into the body fluid from tumor cell nuclei in the tumor-bearing state.

Antibody production in mice. 3. The suppressive effect of antibody on the initiation of secondary immune response

The suppressive effect of antibody on the secondary immune response was analysed using a technique of memory cell transfer into X-irradiated recipients. The response of memory cells stimulated by antigen-bearing cells was markedly suppressed when antibody was passively administered to recipients and this had its maximal effect when administered simultaneously with the cell transfer. The capacity of memory cells to respond to antigenic stimulation and the capacity of antigen-bearing cells to stimulate memory cells were not directly impaired by the suppressive antibody. The marked suppression was observed only when both memory cells and antigen-bearing cells were present together with antibody. These results suggest that antibody-induced suppression appears to be caused by blocking the effective antigenic stimulus from antigen-bearing cells to memory cells.

Evidence is presented indicating that pre-existing antibody plays a regulatory role in the initiation of the secondary response and also controls the expression of memory.