Epidemiology of stomach cancer in Chile--the role of nitrogen fertilizers.

Chile ranks second in the world regarding age-adjusted mortality rates from stomach cancer. Analysis of death rates along its 25 provinces for a 15-year period (1957-1971) shows a peculiar geographic pattern of high and low-risk areas. Three agricultural provinces (Maule, Linares and Nuble, located south of Santiago), population 460,000, show a median rate of 50 x 1 per 100,000.

Aspirin intolerance in chronic childhood asthma: Detected by oral challenge.

Most previously reported individuals with acetylsalicylic acid (aspirin, ASA)-induced asthma have been adults. This study was undertaken to define the prevalence of ASA intolerance among children with intractable asthma. Fifty children (34 boys and 16 girls) ranging in age from 6 to 18 years with extrinsic (atopic) asthma were studied.

Mechanism of cytochrome c peroxidase. O-benzoylhydroxylamine as an analog of hydrogen peroxide.

A number of reagents, some of which are electronic analogs of hydrogen peroxide, will replace it in the reactions of cytochrome c peroxidase. These compounds include N-bromosuccinimide, sodium hypochlorite, and the novel oxidizing agent O-benzoylhydroxylamine. If fragments of the oxidant played a functional role in the structure of the oxidized form of the enzyme, it would be expected that the product formed from O-benzoylhydroxylamine would differ from that formed from hydrogen peroxide.

Effectiveness of isosorbide dinitrate and nitroglycerin in relieving angina pectoris during uninterrupted exercise.

Twenty patients with ischemic heart disease documented by coronary angiograms or ST segment depression in the ECG during treadmill walking, were administered sublingual nitroglycerin 0.3 to 0.6 mg on one occasion and a chewable form of isosorbide dinitrate 5 mg on another occasion during treadmill walking when anginal discomfort was definitely present at a mild degree of intensity.

Reliability of plethysmography, the single breath oxygen test, and spirometry in population studies.

Three thousand five hundred and twenty-eight residents of a census tract in Los Angeles, California underwent pulmonary function testing in a mobile laboratory (the Breathmobile). Tests included respiratory questionnaire, electronic spirometry, the single breath O2 test and body plethysmography. The reliability and sensitivity of the tests performed in the Breathmobile was measured by repeating the same tests and others on a 3% probability sample at the University of California at Los Angeles Pulmonary Function Laboratory.

Lymphocyte tissue culture studies on human heart transplant recipients. I. Screening recipients for serum factors which inhibit the mixed lymphocyte reaction.

The sera of 20 random human heart transplant recipients, drawn before the administration of immunosuppressive medications, were screened for the presence of factors that might inhibit the mixed lymphocyte reaction. The donors for the lymphocyte cultures were unrelated both to one another and to the heart donor and recipient. Inhibition was defined as a reduction of the number of transformed cells produced in vitro to less than one-third of that produced in autologous serum.

Forty-day fever. An epidemic of cytomegalovirus disease in a renal transplant population.

An epidemic of cytomegalovirus disease (CMV) occurred in 38 percent of 34 renal transplant recipients during an 18-month period. A characteristic clinical pattern was noted: 40 days following transplantation, daily fevers recurred for periods of four to six weeks. This fever in conjunction with a diffuse interstitial pneumonitis and impaired hepatic and renal function constituted a diagnostic tetrad.

Lymphocyte culture in solid medium. I. Phytohaemagglutinin stimulation of human blood lymphocytes in chicken plasma clot cultures.

Normal human blood lymphocytes were cultured in chicken plasma clots with a series of PHA-P dilutions. In this situation direct cell-to-cell contact was prevented, and thus a morphological estimate of the actual number of PHA responsive cells was possible in the absence of any cell-to-cell co-operation which might be mediated via cell contact. The distorting effects of transformed cell proliferation on quantification, and of death of the original small lymphocyte population, were similarly obviated.

Use of DNA polymerase I primed by a synthetic oligonucleotide to determine a nucleotide sequence in phage fl DNA.

A sequence of 50 residues in f1 DNA has been determined by the extension of a chemically synthesized octadeoxyribonucleotide by Escherichia coli DNA polymerase I, with radioactive nucleoside triphosphates and f1 DNA template. The polymerized product was synthesized either in the presence of manganese and a mixture of ribo- and deoxyribotriphosphates or in a magnesium-containing reaction with one or more of the four triphosphates absent. The sequence determination depended largely on fractionation of the polymerized products by two-dimensional "homochromatography.

Nucleotide sequences of similar size from the coliphage R17 genome.

A sequence of 33 nucleotides from the coliphage R17 RNA genome was determined. It constitutes the main component of a mixture of fragments that migrate together on electrophoresis in a separation according to molecular weight. Fragments of comparable chain length from 3' end of RNA from coliphage R17, from a region preceding and overlapping the coat-protein cistron ribosome binding site and from the beginning of the A-protein cistron, were also found and characterized.