Increase In Size Of Nodes Research Articles

Cellular events in the lymph node and lung of mice with influenza. Consequences of depleting CD4+ T cells.

The cellularity of the mediastinal lymph nodes of mice infected intranasally with a high dose of an H3N2 influenza A virus increases massively within 5 days. All classes of lymphocytes are involved. A similar, but much smaller, expansion in cell numbers occurs after exposure to a comparable dilution of normal chick allantoic fluid. In the control group, this increase in lymph node size is totally prevented by the in vivo depletion of CD4+ T cells whereas there is only a 50% reduction in the virus-infected mice. The lymphocyte component of the cellular exudate in the lungs of infected mice is dominated by activated, CD8+ T cells, which are also prevalent in the mediastinal lymph nodes. Elimination of the CD4+ subset does not greatly diminish the severity of this inflammatory process. The CD4-depleted mice clear the virus from the lung, and there is little effect on the frequency of virus-specific, cytotoxic T lymphocyte precursors in either the lymph node or the lung. Substantial involvement of CD4+ T cells is not essential for the development of effective cell-mediated immunity in mice with influenza.

Enhancing effects of carbon tetrachloride in mouse hepatocarcinogenesis

The enhancing effects of 4 or 8 necrogenic doses of carbon tetrachloride (CCl 4) on hepatocarcinogenesis were studied in female B6C3F1 mice previously treated with a single dose of N-nitroso- N-diethylamine (NDEA) at 7 days of age. The CCl 4 treatments were given every other week and started either after weaning or at 18–26 weeks of age, and the animals were observed until 36 weeks of age. The number and size of hepatocellular nodules were then scored and analysed. Hepatocellular nodules were not observed in mice receiving either 4 or 8 CCl 4 treatments without NDEA initiation. Both 4 and 8 CCl 4 treatments promoted NDEA-initiated hepatocarcinogenesis, increasing nodule size but not nodule frequency. Eight CCl 4 doses were more effective than 4 and gave the greatest increase in nodule size when administered from 18 to 32 weeks of age. In an additional experiment, 3 mice bearing hepatocellular nodules induced by a single infantile NDEA treatment were administered CCl 4 once and killed 52 h later. Nine neoplastic nodules were examined and found to be resistant to the CCl 4 induced necrosis, although cells in the nodules were actively dividing at the same rate as in the regenerating surrounding normal liver parenchyma. The ability of a few necrogenic CCl 4 doses to enhance hepatocarcinogenesis may be related to a differential cytotoxicity on neoplastic and normal hepatocytes and to a similar mitogenic stimulus on both cell types.

Lymphographic and Echographic Findings in Angioimmunoblastic Lymphadenopathy

Four patients with angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) had lymphograms that did not show a consistent radiographic pattern. Instead, a spectrum of radiologic changes ranging from a moderate increase in lymph node size with slight "foaminess" to total nonopacification was observed. One patient with this disorder had gray-scale echograms that showed enlarged anechoic lymph nodes. The findings in this small group of patients with AILD are indistinguishable from the radiologic and echographic changes seen in malignant lymphoma.

Observations on "reactive (follicular) hyperplasia" as encountered in repeat lymphography in the lymphomas.

A phenomenon encountered in some patients undergoing repeat lymphography is described, which consists of an interval substantial increase in size and granularity of the opacified lymph nodes on the repeat study when compared to the initial study. These findings are diffuse and symmetrical, with the exception that they do not involve previously irradiated lymph node groups. This increase in lymph node size and coarsening of internal architecture is caused by a non-specific lymph node reactive follicular hyperplasia. Such findings on repeat lymphography should not be mistaken for relapsing disease occurring in previously normal lymph nodes, but rather should be recognized as simply representing a non-specific lymph node reactive hyperplasia.

EXTREME ALTERATION OF THE NUCLEOCYTOPLASMIC RATIO IN STENTOR COERULEUS.

SYNOPSIS. Nucleocytoplasmic relationships were explored by producing the extreme alterations in proportion of macronucleus to cytoplasm for which the ciliate Stentor coeruleus is uniquely suitable. Cytoplasmic volumes were varied from about 40 to 6000 times the nuclear volume, as compared with a normal range of approximately 126 to 387. 1. Neither gross reduction nor great excess of the nuclear complement stimulate or inhibit cell division; for division never promptly ensued nor were giant cells or dwarf lines produced. Previous studies(5) have shown that lesser variations in nucleocytoplasmic proportions also have none of these consequences. 2. Hypernucleation produces no noticeable accelerating effect on cell re‐differentiation (oral regeneration), ciliary activity (swimming and feeding), or growth and multiplication. 3. Overnucleation is adjusted by extensive fusion of macronuclear nodes (reducing nuclear surface area) and by gradual resorption of some of the nucleus. 4. Nucleus maximally reduced to one node in normal and greater amounts of cytoplasm almost always results in delays of 2 to 15 times the usual preparatory period for regeneration as well as diminished feeding and impaired digestion, and acts as a stimulus to reorganization—confirming Schwartz(27). In hyponucleates there is a compensatory increase in nodal number following regeneration, reorganization (or division), but only after oral primordium formation—again confirming Schwartz. At least two such formations (regeneration followed by reorganization or division) are required for recovery of a nuclear complement of normal proportions, and this very probably represents a true increase in macronuclear substance as well as in number of nodes.6. In division the number of macronuclear nodes is approximately doubled, such that each fission product begins with about the same number as the parent cell, but the new nodes are generally smaller. Whether, during interfission, a regular increase in size of nodes and the addition, at most, of 3 new nodes represents a real increase in nuclear substance is questionable in view of the fact that isolated single nodes remain as such for days without increase until oral primordium development. Cytosomal events may be said to give the stimulus to renodulation and possibly also to macronuclear growth as they do for micronuclear growth in mitosis.7. When the nucleus is maximally reduced, the single node may be resorbed and no oral regeneration occurs. Alternatively, the macronuclear bead supports delayed regeneration but fails, temporarily or permanently, to increase itself. Less commonly, neither oral nor nuclear regeneration occurs though the single node persists. All indicate a statistical probability of some injury to a reduced nucleus when in an excess of cytoplasm. 8. Early oral primordia are resorbed in regenerators (and dividers and reorganizers) when the macronucleus is reduced to one node, but the single node which could not support continued regeneration is nevertheless sufficient for subsequent re‐regeneration. 9. At most the oral primordium can develop 3 steps further (more often 2, sometimes none) after complete enucleation. Hence there is little storage of nuclear support. Stage‐5 anlagen, still without visible trace of mouth‐parts, can develop fully, suggesting there is little synthesis of materials in later development but largely morphogenetic movements of invagination and translocation in completion of the feeding organelles.10. Enucleated stentors can feed quite well at first but not at all later. All indications are that they are incapable of digesting food organisms. Mononodal stentors fare somewhat better and recover normal function as they regenerate the nuclear chain. Enucleates die on the average sooner than starved nucleate controls, but there is considerable overlap in survival times.Some inferences from these findings are discussed. In experiments with other concerns, a sufficient amount of macronucleus should be used or retained, else the disproportion becomes a factor in itself.

Contrast radiographic demonstration of a lymph node metastasis.

INFORMATION on the number and extent of metastases—particularly early metastases prior to treatment or surgical exposure of malignant tumors—has always been desired. In our present state of knowledge, metastatic tumor in lymph nodes is diagnosed clinically by a considerable increase in node size, by the enlarged nodes exerting pressure on adjacent structures, or by lymphedema. In each of these instances, metastases can be assumed to be extensive and the prognosis generally unfavorable. Contrast lymphography offers some hope for solution to the problem of early diagnosis of metastases in the intact patient. Tjernberg 1 first demonstrated artificially implanted tumor in the nodes of rabbits. Fischer and Zimmerman 2 produced simulated metastases and clearly demonstrated discrete filling defects in otherwise normal popliteal nodes of dogs. From these animal experiments, the possibility of demonstrating discrete node metastases has gained support. We are presenting a case of a metastasis in a lymph node

Biochemical Nitrogen Fixation Studies. I. Evidence for Limited Oxygen Supply Within the Nodule

Respiration studies were undertaken with a view to obtaining fundamental information concerning the metabolic processes of legume nodules, inasmuch as the knowledge gained should facilitate investigation of the process of nitrogen fixation. The results obtained by standard manometric procedures with detached nodules from eight species of legumes may be summarized as follows: 1. The rates of respiration of nodules maintained in various oxygen-nitrogen mixtures increased as the oxygen percentage increased. The QO2 values varied between 0.62 and 6.25 with an average of about 2.2 in air, and were about 2.4 times as great in pure oxygen, with maxima for the eight species varying between 4.3 for soybean and 8.9 for hairy vetch. 2. The respiratory quotients increased with increase in size of nodule and with decrease in concentration of oxygen. In air the values varied between 1.0 and 2.0, depending largely on the size of the nodules. In pure oxygen, excluding very large nodules, the values averaged 1.03. 3. The addition of glucose to the nutrient medium produced a mean increase in QO2 of about 12 per cent in air and 14 per cent in 100 per cent oxygen. It increased the R.Q. at the lower concentrations of oxygen but not appreciably in pure oxygen. 4. These results with detached nodules are interpreted as indicating that with most nodules maintained in air, or with large nodules at oxygen concentrations even as high as 100 per cent, the interior of the nodules is under anaerobic or partially anaerobic conditions. The evidence further indicates that under natural conditions in the soil the oxygen supply inside most nodules is also limited. 5. Crushed nodules gave higher QO2 values when maintained in air than did whole nodules, but usually lower values than whole nodules in pure oxygen. This method of increasing the aeration of the inner cells of the nodules was not very satisfactory. 6. The nodules of all the species showed rather similar responses, the variations between species being not much greater than that within species.