Joseph A. Watson

Formation of a histidine-peroxide adduct by H2O2 or ionizing radiation on histidine: chemical and microbiological properties.

We find that small amounts of hydrogen peroxide in the presence of histidine strongly inhibit the growth of Salmonella typhimurium in glucose medium (pH 70). Other amino acids and analogues, e.g. imidazole, alanine, and histamine, are relatively or completely inactive under the same conditions. We also find that gamma-irradiated oxygenated solutions of histidine inhibit bacterial growth to an extent proportional to the amount of H2 0 2 produced radiolytically. In the glucose-containing microbiological growth medium (pH 70, t = 37°c), the presence of histidine greatly retards the normal rate of disappearance of added H202. These and other chemical and microbiological observations reported here suggest that histidine and H202 readily form a stable adduct. A histidine-peroxide crystalline adduct has been prepared and chemically characterized (Dirscherl and Mosebach 1954). Subsequently the preparation of other amino-acid-peroxide adducts has been described (Dirscherl and Moersler 1964).

Deposition and Clearance Following Inhalation and Intratracheal Injection of Particles

The pulmonary deposition patterns and the clearance rates of insoluble particles from the lungs of rats were measured during the early post-exposure period following inhalation and intratracheal injection. The data were analyzed by assuming that the pulmonary system consists of a series of compartments and that these compartments are cleared sequentially in time via the trachea. Based on these assumptions, the intratracheal injection technique produced a relatively greater deposition of particles in the lower respiratory tract as compared with inhalation. The clearance kinetics of particles from the lungs were similar for particles deposited in equivalent compartments of the pulmonary system by the two methods of exposure, suggesting that clearance from a given lung compartment is independent of the distribution of particles within that compartment. If this inference is valid, the clearance kinetics obtained following intratracheal injection of particles should not differ from those obtained following inh...

Pulmonary macrophage clearance. The hourly rates of transfer of pulmonary macrophages to the oropharynx of the rat.

Estimates of the number and the cytologic eel! types transferred from the lungs to the oropharynx of rats are derived within a factor of 2 by the combined use of an esophageal sputum-collection procedure and mucolytic digestion technique which utilizes N-acety-L-cysteine (NAC). The hourly clearance of pulmonary phagocytes to the oropharynx was estimated to range between 1.24 × 106; Geometric Standard Deviation (GSD) 1.3 and 2.47 × 106; GSD 1.3.

Organic peroxides and the antibacterial action of irradiated sucrose as affected by catalase.

Sucrose solutions irradiated in the presence or absence of oxygen inhibit the growth of Salmonella typhimurium. The addition of catalase prior to or shortly after inoculation of the organisms into ...

EXPERIMENTAL CARCINOGENESIS. BRONCHIAL INTRAMURAL ADENOCARCINOMAS IN RATS FROM X-RAY IRRADIATION OF THE CHEST.

One hundred eighty‐six rats and 202 hamsters, that survived the respective time periods when the first lung cancer was diagnosed in each species, had been given an exposure of 3000 R or 4000 R of x‐irradiation applied externally to the chest. About 43% of the rats, but only 2% of the hamsters, developed lung cancer. To enhance the prevalence of lung cancer, some of the irradiated animals were injected intratracheally with 9, 10‐dimethyl‐1, 2‐benzanthracene (DMBA). Lung cancer prevalence in irradiated animals injected with DMBA was no higher than that in irradiated animals not so injected. Intratracheal injections of DMBA in nonirradiated rats did not result in tumor production but, in nonirradiated hamsters, DMBA caused a 6% prevalence of lung cancer. The mortality rate of both animal species showed a more than additive effect in animals given the higher x‐ray dosage plus intratracheal injections of either DMBA or iron oxide alone. The lung cancers in the irradiated rats predominantly affected bronchi (86%) and were mostly adenocarcinomas (88%). The cancers were generally intramural and were covered by an intact and normal surface epithelium. Their origin appeared to be from aberrant intramural glands. These glands are not found in the bronchi of germ‐free rats but do occur in bronchi thickened by severe endemic chronic bronchitis.

Upper respiratory tract clearance in rats after thoracic irradiation.

The thoracic region of rats was irradiated to initiate a sequence of histopathological changes in the lungs. The clearance of particles that were injected intratracheally into the lungs was measure...

Abscopal and Direct Effects on Calcium Mobilization, Alkaline Phosphatase Levels, and Dentin Formation following X-Irradiation of either the Rat Incisor or the Thyroid-Parathyroid Region

SYNOPSIS IN INTERLINGUA EFFECTOS INDIRECTE E DIRECTE OBSERVATE IN LE MOBILISATION DE CALCIUM, LE CONCENTRATIONES DE PHOSPHATASE ALCALIN, E LE FORMATION DE DENTINA POST LE IRRADIATION A RADIOS X DE (1) INCISORES o (2) LE AREA THYROIDE-PARATHYROIDE DEL RATTO.—Rattos esseva subjicite a injections intraperitonee de radiocalcium post irradiation e esseva sacrificate a intervallos de 4 dies usque a 32 dies post le irradiation. Le characteristic lesion inducite per irradiation esseva observate in le incisores maxillari post le irradiation directe de iste dentes. Nulle tal lesion esseva producite in le dentes de animales con irradiation del area thyroide-parathyroide in consequentia de un effecto indirecte. Tamen, ambe gruppos experimental manifestava simile alterationes in le mobilisation de calcium del incisores maxillari.

The Changes in Fluorescence of Acridine Orange-Stained Hela Cells During Ultraviolet Illumination

HeLa cells were stained with a 1/12,000 concentration of acridine orange at pH 7.2 for 3 min and the fluorescence emission was measured quantitatively for effects of ultraviolet illumination with durations including intervals between 5 and 210 min. The total photometric fluorescence intensity increased for the first 30 min, then decreased with illumination time. The initial maximum fluorescence intensity occurred at 525 nm and shifted progressively to shorter wavelengths. Fluorescence intensity above 580 nm decreased with increasing duration of illumination time while that below 580 nm showed an initial increase in intensity followed by a gradual fading.