Reach Maximum Size Research Articles

Sequence of perivascular liquid accumulation in liquid-inflated dog lung lobes.

The peribronchovascular interstitium of the lung is a potential space that expands in pulmonary edema with the formation of large liquid cuffs. To study the time course of cuff formation we inflated nine isolated dog lung lobes with liquid to total lung capacity, rapidly froze them in liquid N2 after inflation periods of 1-300 min, then photographed 20 blocks of each lobe at X3 magnification. From the photographs we measured the ratio of cuff area to vessel area for arteries and veins of 0.05-8 mm diam. We found that the cuff-to-vessel area ratio attained a maximum value of 3-4, which was independent of vessel size. However, the first cuffs to reach maximum size were those around vessels of 0.1-0.5 mm diam, whereas cuffs around larger vessels filled more slowly. No cuffs were visible around vessels smaller than 0.1 mm diam. After 45 min cuffs had formed around 99% of all vessels larger than 0.5 mm diam but had formed around only 38% of veins and 91% of arteries of smaller diameter. We simulated the observed rate and pattern of cuff growth using electrical analog models. The filling pattern and model analyses suggest that liquid entered the interstitium from an air space site associated with arteries of approximately 0.1-1.0 mm diam, spread to adjacent sites, and eventually reached the lobe hilum. The estimated perivascular interstitial flow resistance decreased approximately 100-fold with cuff expansion.

SCell-Mediated Immune Response to Shope Fibroma Virus-Induced Tumors in Adult Rabbits<xref ref-type="fn" rid="fn2">2</xref><xref ref-type="fn" rid="fn3">3</xref>

The parameters of cell-mediated immune responses of adult rabbits infected with Shope fibroma virus (SFV) were characterized by measurement of the size of local draining nodes, number of cells per lymph node, mitogen responses of lymphocytes, and kinetics of virus-specific cell-mediated lymphocytotoxicity (CML). In addition, the cytolytic effector population was characterized. After intradermal injections, tumors appeared within 3-4 days, reached maximum size in 10-12 days, and then regressed completely with 24 days. The size of local popliteal lymph nodes, in particular the diffuse cortex (paracortex), and the number of cells per node increased during tumor growth but then declined as the tumor regressed. Maximum specific CML to SFV-infected kidney cell monolayers (RK-13) occurred 10 days after inoculation of SFV and correlated with the initiation of tumor regression. Adult cytotoxic lymphocytes passed through nylon wool, and most of their activity was removed by treatment with antithymocyte globulin plus complement. Cytotoxic T-cells from SFV tumor-bearing rabbits killed only targets infected with SFV and not targets uninfected or infected with vaccinia virus. Therefore, T-cell-mediated virus-specific CML appeared as a major immune effector mechanism that correlated with tumor regression. However, antibody-dependent cell-mediated and NK cytotoxicity were also demonstrable. The presence of different cell-mediated cytotoxic mechanisms suggested a heterogeneity of effector mechanism.

Studies on Genetic and Vaccination-Induced Resistance of Chickens to Lymphoid Tumor Transplants 2. Transmissible Lymphoid Tumor of Olson

Transmissible lymphoid tumor (TLT) was inoculated in wing webs of five-week-old chickens of 6 strains. About half of the chickens of each strain had been vaccinated with turkey herpesvirus (HVT) one week before challenge in the wing web with TLT. Tumors which developed at the site of inoculation usually reached maximum size within 2 weeks and then regressed. In some chickens, however, tumors developed in visceral organs and caused death in the 2nd through 5th weeks postinoculation. Comparisons among strains of chickens in Expt. 1 revealed no differences in mortality. Vaccination with HVT reduced mortality and also the incidence of wing-web tumors (WWT) in all strains of chickens. A lymphoid leukosis virus and a Marek's disease (MD) virus of low virulence were detected in preparations of TLT, and it is suggested that the immunity induced by vaccination may have been directed against tumor antigens associated with MD virus.

Histological Comparison of Cucumber Fruits Developing Parthenocarpically and Following Pollination

1. The development of cucumber fruits of a naturally parthenocarpic variety (Rollison's Telegraph) was studied before and following pollination. The development of megagametophyte, embryo, and seed coats was observed in detail. Tissues of the perianth, stigma, nectary, and neck shriveled within a week after pollination, and a protective periderm formed at the apex of the live tissue beneath. Twenty days after full bloom hardened seed coats contained large well-developed embryos. 2. Development of untreated fruits in which there was no pollination was essentially the same, except for the absence of embryos and endosperm, the disintegration of megagametophytes, and the slightly smaller size of the seed coats. 3. In other cases transverse cuts were made through the lower portion of the floral tube and a 2 per cent mixture of indoleacetic acid in lanolin was applied to the cut surface. 4. When application of the mixture was made 4 days before full bloom, apical tumors were formed, involving tissues of the nectary, floral tube, and neck. These reached maximum size in about 12 days. Neither vascular tissues nor root primordia were differentiated in the tissues of the tumors. Ovules developed to about half normal size, and seed coats became partially hardened. 5. When pure lanolin was applied 4 days before full bloom, death of the apical tissue was greatly retarded and usually no periderm was formed. Ovules developed as in untreated controls. 6. When indoleacetic acid in lanolin was applied at full bloom the apical tissues remained alive but proliferated very little. Ovules were intermediate in size between those of controls and those of fruits given the pre-bloom treatments with indoleacetic acid in lanolin. 7. When pure lanolin was applied at full bloom, development was essentially the same as that of untreated controls. 8. In the unfertilized ovules of parthenocarpic fruits the nucellus generally developed into a massive tissue with a large central cavity. 9. Meiosis and megagametophyte development were not noticeably affected by any of the treatments. 10. In a single instance following premeiotic treatment with indoleacetic acid there was some proliferation of gametophytic tissue.

Gross Morphology and Histology of Developing Fruit of the Apple

1. Gross development and principal tissue changes in the fruit of the apple from 1 month before full bloom throughout the growing season to fruit ripening are figured and discussed, and suggestions are made regarding the methods and the values of measurements of various parts. 2. Interpretation of the apple as five drupelike carpels contained within the fleshy torus or receptacle has seemed to describe the structures observed. 3. The curve of gross development of the entire fruit is nearly a straight line for the early summer variety (Early Harvest), but for each successively later-ripening variety (McIntosh and Rome) the curve flattens as the season progresses. Although perhaps associated with environment, the rate of growth is shown to be a varietal characteristic, in which each successively later-ripening variety has a slower rate. 4. The cartilaginous portion of the carpels develops rapidly for 2-4 weeks after full bloom, reaching maximum size in transverse diameter the earliest of any of the tissues ...