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Ionizing radiation doses of 500 to 1500 r resulted in nuclear blistering, gigantism, and cell division arrest of monolayers of strain L. These aberrations were related to dose and duration of the post-irradiation period. Doses from 100 to 2500 r produced effects varying from temporary division arrest to complete division arrest.

1. 1. The ability of colchicine, ATP, DPN, and TPN to protect and resuscitate ultraviolet irradiated cultures of Tetrahymena pyriformis WH-6 was investigated. 2. 2. All chemicals afforded some protection by delaying the onset of clumping and loss of motility. Only DPN- and colchicine-treated organisms were able to divide after receiving an irradiation dose lethal to control cultures. However, DPN could not protect old cultures. 3. 3. The evidence shows that UV-radiation death involves inhibition of DPN metabolism as well as DNA synthesis-related phenomena. 4. 4. Chemoresuscitation of irradiated cultures was not obtained.

The wave function for a free electron in the presence of an atom is considered for the case of the Coulomb potential, a potential which ignores both the effects of electron exchange and core polarization. A sample calculation involving the neutral oxygen atom is carried through. From the single-determinant wave function for the $^{3}P$ ground state of this atom the Coulomb potential is developed, and the important parts of the potential for the $s$- and $d$-wave portions of the free-electron wave function are considered. The relevant Schr\"odinger equations are solved by means of an IBM 704 program which is written so as to be readily adaptable to electrons in the presence of other atoms or ions having electrons through $2p$. In our oxygen example the wave function calculations were carried out for values of the free-electron linear momentum ranging from 0.01 through 0.80 atomic unit.

A severe hypotensive response to parenterally administered reserpine occurred in a patient with mild toxemia of pregnancy. Later, when the effect of the reserpine had diminished considerably, cardiac arrest developed. Some hours after resuscitation, the patient died and was found at necropsy to have fatty metamorphosis of the liver. Acute fatty metamorphosis of the liver in pregnancy is an uncommon lesion. The principal histologic finding was a foamy vacuolar type of fatty change involving the central portion of the liver lobules. Liver disease was unsuspected in this patient because of the absence of jaundice. The possibility of liver disease should be entertained whenever persistent nausea and vomiting develop in the latter part of pregnancy, especially when severe toxemia and pyelonephritis can be excluded.

The effect of radiation (500–1500 R) on the enlargement and size distribution of Strain L cells in monolayer culture was studied. The average cell volume, total culture volume, total cell number and cell size distribution were correlated with the degree of radiation injury and recovery during a 4-day postirradiation (PI) period. Cultures irradiated with 500 R resulted in an inhibition in cell division and giantism followed by recovery, a moderate depression in culture volume, and shifts in cell size distribution toward normal values during the 4-day PI period. Cultures irradiated with 1000 and 1500 R also showed dose-correlated inhibition of cell multiplication and giantism. However, these doses had virtually equivalent effects on total culture volume and cell size distribution. The increase in cell size was directly proportional to the three doses used. Cultures irradiated with 1000 R (on the 4th day PI) showed size changes which reflect a recovery process the cells undergo after the initial enlargement. These data support the view that the factors associated with cell divisior are much more sensitive than those associated with cell growth.

Phase contrast cinemicrographic methods and fixed preparations were used to ascertain the effect of prolonged exposure of strain L cells to Eagle MEM that was gassed with a mixture of 95% O 2 − 5% CO 2 . The results of this study showed that division in synchronous strain L cells is inhibited by exposure to hyper-oxygenated medium when the cells are in early G1. The effect of elevated levels of oxygen delayed the separation of sister cells following mitosis by 4 to 12 h. Nucleolar morphology suggested that oxygen-treated cells may proceed slowly through S phase where they are partially arrested. Some synchronous cells were observed to round up after 3 h exposure to hyper-oxygenated medium. Some cells lysed after rounding up. Asynchronous strain L cells exposed to hyper-oxygenated medium exhibited cytological anomalies such as nuclear blistering, extrusion of nuclear material, multinuclear giant cell formation, and nuclear bridge formation following nuclear division.

1. 1. Development of a technique for selective harvesting of synchronous strain L cells has made possible the study of nucleolar changes during the cell cycle. The pattern of DNA synthesis was determined autoradiographically, and cultures which had been planted for 3, 14 and 19 h were chosen as representative of the G1, S and G2 periods, respectively. Changes in morphology, position, number and size of nucleoli were assessed, both cinematographically and using fixed preparations. 2. 2. The significant reduction in nucleolar number between G1 and mitosis was found to be due largely to fusion. Increase in size resulted from both fusion and synthetic activity within the nucleolus. 3. 3. Irregular morphology of nucleoli, marked association with the nuclear membrane and amoeboid movement were characteristic of nucleoli both in G1 and G2. During S phase nucleoli were oval-shaped and centrallylocated; they exhibited much less movement. 4. 4. The possible significance of these cyclic nucleolar phenomena as related to other nuclear changes during the cell cycle has been discussed.

We first outline the theoretical basis for our calculations of the spectral radiance of equilibrium air. The source of and in some cases, possible discrepancies in the input parameters and approximations involved in the calculations are next discussed briefly. In the resultant figures we display (1) the frequency-dependent radiance of the various species individually and summed over all species for various temperatures and densities, (2) the frequency-dependent total radiation as a function of density for a particular temperature, and (3) the constituent and total radiation as a function of temperature for various densities and as a function of density for various temperatures. The temperature range considered was from 3000–9000°K, and the relative density ranged from one-thousandth normal to one hundred times normal.

The effect of cold exposure, epinephrine injection, and a combined cold-epinephrine treatment on the eosinophil level of the turtle, Pseudemys elegans, was studied in order to ascertain information regarding the sensitivity of the endocrine and nervous systems of a poikilotherm to stresses. A low temperature environment produced an eosinopenia; the average fall was 34.8% below the control level. Epinephrine injection resulted in an eosinophilia; the average rise was 37.4% above the control level. Combined treatment with cold and epinephrine resulted in an eosinopenia; the average fall was 32.8% below the control level. It is concluded that the turtle shows an endocrine response to cold stress.

SUMMARY. The effect of surface-active agents on the permeability, survival, and pseudopod formation of the rhizopod, Pelomyxa carolinensis, was studied. Surfactants increased the rate of uptake of Na22 in almost all instances. Tweens which lower surface tension, stimulated or caused pseudopod formation; Tween 80 was the least toxic. The fatty acid component as well as the hydrophile-lipophile balance of the surfactant may influence the rate.

SummaryUrea and ammonia were estimated every day for 14 days in sterile cultures of Colpidium campylum. Qualitative tests for uric acid were also made. Ammonia production increased linearly with age of culture. Urea was produced only during the logarithmic phase of growth. The cause of the disappearance of urea is unknown. No uric acid was present at any time.

Pulsatile perfusion of rabbit hearts with bloodless fluid was performed for 2 to 6 h at normothermic and hypothermic temperatures. All perfused hearts became edematous with the maximum gain in weight occurring at 37°C and the minimum at 5 to 15°C perfusion. Concomitantly, the dry weight fraction of hearts decreased, with the minimum decrease noted at 15°C and the maximum at 37°C perfusion temperature. The DNA content of perfused hearts declined, with the sharpest drop registered at 2-h perfusion and the maximum retention of DNA observed at 25°C. Protein content of myocardium in perfused hearts decreased with the minimum loss observed during 15°C perfusion. In contrast to DNA and protein, the RNA levels were essentially unchanged. It is concluded the pulsatile perfusion within a 15 to 25° temperature range insures maximum retention of myocardial dry weight fraction, DNA, protein and RNA.

http://archive.org/details/astudyofeffectof1094514645 U.S. Coast Guard (U.S.C.G.) author U.S. Navy (U.S.N.) authors.

Publisher Summary This chapter discusses measurement of electron diffusion length by photoluminescence in p-doped GaAs substrates and p-doped epitaxially grown GaAs photocathodes. The knowledge of the diffusion length of electrons in p-doped GaAs photocathodes is of paramount importance in determining the yield of such cathodes. In this study, three aspects of the problem were investigated. Photocathodes were grown epitaxially on various single-crystal GaAs substrates with heavy Zn doping. Several substrates were studied with different surface preparations and their photoluminescence characteristics were compared. Several epitaxially grown films, with different characteristics, were measured while these films were still on the substrate. The effects of the photocathode activation process on these films were studied by measuring photoluminescence before activation and after several activation cycles during which the samples were exposed to high-temperature heat treatment. Luminescent intensities varied over a wide range and other features of the spectra such as half width, band shape, and peak position displayed considerable variations as well. The qualitative conclusion that is drawn from this study is that both intensity and half width increase with increasing doping. This is supported by theory as well, although the relations are a little more involved regarding the half width.

The incorporation of [3H]-5-uridine into cytoplasmic 18S and 28S ribosomal ribonucleic acid (rRNA) was examined in Colcemid-synchronized strain L cells during G1 and S phases of the cell cycle in the presence of 5×10−5 m uridine, which was determined to be the saturating concentration for this system. The data show that in S phase a significant increase occurs in the level of [3H]-5-uridine incorporation into each rRNA species. During a 90-min exposure period, S phase cells incorporate 3.4 times as much [3H]-5-uridine into 18S rRNA and 1.9 times as much into 28S rRNA as do G1 cells. The time required for maturation of the ribosomal RNA species during G1 and during S phase is the same, with 18S rRNA appearing in the cytoplasm in 20 min and 28S rRNA in 40 min.