BCG-induced granulomatous pulmonary inflammation and splenomegaly in mice: A T-cell-dependent response

When C57BL/6 mice were injected iv with BCG in an oil-in-saline emulsion, they developed intense pulmonary granulomatous inflammation (PGI) and splenomegaly as well as chemotactic activity for macrophages and angiotensin-converting enzyme (ACE) in their lung fluids. PGI, splenomegaly, and levels of chemotactic activity and ACE were markedly reduced in T-cell-deficient “B” mice. The capacity to develop PGI was fully restored and splenomegaly was partially restored in “B” mice by the provision of syngeneic thymocytes, spleen cells, or purified T cells. These results indicate that the full expression of BCG-induced PGI is dependent upon thymus-derived cells and is associated with high levels of chemotactic activity for macrophages and ACE in the lung lavage fluid. Although BCG-induced splenomegaly appears to be T cell dependent, it did not reach its full magnitude in reconstituted “B” mice.     

Trypanosoma musculi: Passive hemagglutination technique to measure antibody in mice

A passive hemagglutination assay was developed to measure Trypanosoma musculi-specific antibody in mice. Indicator-erythrocyte donor mice received 550 rad ⁶⁰Co 24 hr before intraperitoneal injection of 3 × 10⁴T. musculi. T. musculi antigen-coated erythrocytes were obtained from these mice on Day 9 postinfection. T. musculi antigen-coated erythrocytes obtained in this manner were used as indicator erythrocytes in a passive hemagglutination procedure. Serum from hyperimmunized mice (three consecutive infections at 21-day intervals) gave titers as high as 1:1024. Titers of 1:256 and 1:512 were obtained from singly infected mice on Days 18 and 28 postinfection, respectively. In marked contrast, nude mice infected with T. musculi did not produce a detectable agglutinating antibody response. Erythrocytes obtained from either irradiated (550 rad ⁶⁰Co) uninfected mice, nonirradiated infected mice, or normal mice did not agglutinate when combined with any of the sera tested. These data suggest the usefulness of this passive hemagglutination assay for the measurement of antibody to T. musculi in the serum of infected mice.     

Possible link between converting enzyme inhibition and renomedullary interstitial cells

The kidney exerts both prohypertensive and antihypertensive functions. Part of the anti-hypertensive function of the kidney is mediated by the renomedullary interstitial cells (RIC), as an endocrine-type function. Six experimental models of hypertension and their relation to the antihypertensive function of the RIC are discussed. It is proposed that the anti-hypertensive function of the RIC may be deficient by the three mechanisms: 1) absence of the cells (as in the renoprival state); 2) severe damage to the cells (as in partial nephrectomy-salt hypertension of the rat and late malignant hypertension of the rabbit); and 3) constraint of the function of these cells (as in angiotensin-salt hypertension due to a lower salt intake). The constraint may result from excessive angiotensin, either by a direct effect or via a hemodynamic mechanism. The converting enzyme inhibitors (CEI) fail to exert their antihypertensive function when the RIC are absent or damaged. Conversely, the CEI are effective in those models associated with intact RIC. CEI appear to exert their antihypertensive action partly through an effect on RIC.     

Comparative sensitivities of electrophoretic assays for human enzymes

The sensitivities of 26 starch gel electrophoretic enzyme assays have been compared using HeLa human cells and A9 mouse cells grown in vitro.This research was supported by National Institutes of Health Grant No. USPHS GM 09966.     

Social organization of confined male collared lemmings (Dicrostonyx groenlandicus Traill)

This study describes and quantifies the social organization and agonistic behaviour of adult male collared lemmings (Dicrostonyx groenlandicus) in an indoor enclosure. Five groups of four lemmings were observed during separate 8-day tests. Experimental design permitted an increase in group size while density remained constant. When in groups of two, males established stable dominant-subordinate relationships and, when in groups of four, they formed stable non-linear dominance hierarchies. For either group size, frequency of agonistic behaviour declined over time. Habituation, formation of dominance relationships and spatio-temporal partitioning of space are suggested as possible explanations of this decline. Percentage of initial body weight lost during the experiments varied inversely with social rank. Possible causes of this weight loss are discussed. Social relationships in this study are discussed in light of field observations of male lemming home range distribution.     

Assessment of counting efficiencies for labeled protein and other macromolecules in filter disk assays

A several-fold greater counting efficiency is observed for protein labeled with [³H]leucine than for free [³H]leucine using a conventional filter disk assay. A similar, though less marked, effect is noted for ¹⁴C-labeled molecules. These results are comparable to those reported by others for counting efficiencies of labeled DNA and deoxynucleotides and illustrate the generality of this effect with regard to macromolecules and their low-molecular weight precursors. This phenomenon, presumably due to differences in the distribution of large and small molecules within filters, gives rise to errors in the quantitation of macromolecule synthesis if a counting efficiency identical to that of the precursor is assumed to apply. A convenient method for determining counting efficiencies of various molecules bound to filters is presented which eliminates this problem.