Applicability of imprints to immuno-ultrastructural studies of lymphoid tissues

In order to evaluate the applicability of imprints to immuno-ultrastructural studies of lymphoid tissues, we compared distribution pattern and morphology of B cells, T cells, T-cell subsets, and follicular dendritic reticulum cells (DRC) at the light and ultrastructural level in imprints and sections of tonsils and lymph nodes. The surface antigenic profile of lymphoid cells was revealed with monoclonal antibodies in an avidin-biotin-peroxidase complex (ABC) method. Distribution of lymphoid cells in coherent areas of imprints recapitulated their disposition in sections of respective lymphoid tissues. Preservation of microanatomical relationships and ultrastructure of lymphoid cells in imprints allowed evaluation of associations and fine structural detail of lymphoid cells. Morphologic configurations of B cells in imprints, confined to round aggregates, were similar to fine structural morphology of B cells in mantle zones (MZ) and germinal centers (GC). Processes of DRCs in imprints formed conformations resembling their meshwork within follicles and mantled lymphoid cells. In imprints and sections, lymphocytes of cytotoxic/suppressor phenotype had a large amount of cytoplasm with many organelles. In contrast, cells of helper/inducer phenotype displayed a high nucleocytoplasmic (N/C) ratio and small numbers of organelles. Thus, imprints represent an easy, fast, and reliable method that lends itself to immunoultrastructural studies of lymphoid tissues.     

Effects of temperature on the development,growth, and survival of larvae and pupae of a north-temperate chrysomelid beetle

Summary Developoment, growth, and survival of larvae and pupae of the red turnip beetle, Entomoscelis americana Brown, were studied in 10 constant and four alternating temperature regimes (10 to 32.5° C), in field-cages, and in natural populations in Manitoba. This beetle has a northtemperate distribution in North America. Larval and pupal development occurs in spring and normally is completed before the end of June. Growth and development occurred at all constant temperatures tested, but survival was low at the extreme temperatures. Therefore, the threshold and upper limit were near 10 and 32.5° C. The developmental times of the sexes did not differ and decreased with temperature, except possibly at 32.5° C. The average weight of adult females increased with temperature up to 32.5° C and those of males up to 25° C. Considering developmental rate, survival, adult weight, and incidence of malformed adults, the optimum temperature was estimated to be near 27.5° C.Development was accelerated significantly (6 to 9%) in alternating regimes with temperatures differing by 10° C, but not in regimes differing by 5 and 15° C. All alternating regimes increased adult weight, 5 to 17% for females and 2 to 10% for males. Field cage studies confirmed the increase in adult weight, but not the acceleration in development.A three-parameter normal function described accurately the relationship between developmental rate and constant temperature. A computer simulation model based on this equation estimated developmental times in field cages to within one to five days. For natural populations the model overestimated the developmental times by five to 16 days. The discrepancies between model estimates and observed developmental times in natural populations apparently were due to the elevation of larval and pupal body temperatures above air temperatures by behavioral thermoregulation. The elevation of body temperature was estimated to be equivalent to the addition of 5 to 6° C to the maximum daily air temperature. The adaptations and responses of this beetle to the cool spring temperatures of the north-temperate region are discussed.Contribution No. 1164, Agriculture Canada, Research Station, Winnipeg, Manitoba, Canada     

Histamine-induced pulmonary edema distal to pulmonary arterial occlusion

Histological studies provide evidence that the bronchial veins are a site of leakage in histamine-induced pulmonary edema, but the physiological importance of this finding is not known. To determine if a lung perfused by only the bronchial arteries could develop pulmonary edema, we infused histamine for 2 h in anesthetized sheep with no pulmonary arterial blood flow to the right lung. In control sheep the postmortem extravascular lung water volume (EVLW) in both the right (occluded) and left (perfused) lung was 3.7 +/- 0.4 ml X g dry lung wt-1. Following histamine infusion, EVLW increased to 4.4 +/- 0.7 ml X g dry lung wt-1 in the right (occluded) lung (P less than 0.01) and to 5.3 +/- 1.0 ml X g dry wt-1 in the left (perfused) lung (P less than 0.01). Biopsies from the right (occluded) lungs scored for the presence of edema showed a significantly higher score in the lungs that received histamine (P less than 0.02). Some leakage from the pulmonary circulation of the right lung, perfused via anastomoses from the bronchial circulation, cannot be excluded but should be modest considering the low pressures in the pulmonary circulation following occlusion of the right pulmonary artery. These data show that perfusion via the pulmonary arteries is not a requirement for the production of histamine-induced pulmonary edema.     

Purification and characterization of human T-lymphocyte-derived erythroid-potentiating activity

The human T-lymphoblast cell line, Mo, secretes a number of lymphokines, including erythroid-potentiating activity (EPA), an important early regulator of erythropoiesis. We report purification of EPA to homogeneity, from serum-free Mo-conditioned medium. Purification was accomplished by sequential concentration, ammonium sulfate precipitation, lentil lectin affinity chromatography, gel filtration, and reverse-phase high-performance liquid chromatography. EPA was assayed by its ability to stimulate the growth of large erythroid colonies (bursts) from normal human peripheral blood. The purified EPA has a molecular weight of 28,000 and appears as a single band when analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing or nonreducing conditions. Purified EPA stimulates the growth of both early and late erythroid precursors from human bone marrow, as well as colony formation by the K562 human erythroleukemia cell line. Purified EPA has no colony-stimulating factor activity nor does it appear to be a structural protein of the human T-cell leukemia virus subtype II which infects the Mo cells.     

The effect of propranolol on whole-body microvibrations during examination stress

Whole-body microvibrations (MV) in three dimensions were measured in 51 volunteers, all medical students, 26 without and 25 with beta-receptor blockade (propranolol), immediately before a practical physiology examination and during the ensuing vacation. Propranolol impeded the increase in MV values in all three axes, significantly those in the z axis (vertical), the differences in MV values between the two measurements being minimal in the beta-receptor blocked group. On the other hand, propranolol enhanced MV in the x axis (anteroposterior) and the y axis (transverse), the y axis difference being significant only in females. Propranolol obviously relieves examination stress: the majority of candidates (52%) felt "quieter" in the examination with than in other similar situations without beta-receptor blockade. Propranolol was, however, without effect on the examination results. The rectified impulse in the z axis when related to body weight (Jz) correlates linearly with the calculated cardiac output. Propranolol, however, reduced cardiac output more than Jz, pointing to a Jz component non-sensitive to beta-receptor blockade. The part played by muscle tonus, mainly reflected in the y axis, thus remains unknown. The large and slow oscillations in the x and y axes, observed particularly in beta-receptor blocked females, might be attributed to diminution in standing ability.     

Complete nucleotide and derived amino acid sequence of cDNA encoding the mitochondrial uncoupling protein of rat brown adipose tissue: lack of a mitochondrial targeting presequence.

A cDNA clone spanning the entire amino acid sequence of the nuclear-encoded uncoupling protein of rat brown adipose tissue mitochondria has been isolated and sequenced. With the exception of the N-terminal methionine the deduced N-terminus of the newly synthesized uncoupling protein is identical to the N-terminal 30 amino acids of the native uncoupling protein as determined by protein sequencing. This proves that the protein contains no N-terminal mitochondrial targeting prepiece and that a targeting region must reside within the amino acid sequence of the mature protein.     

Isolation and Purification of Prodigiosin from Vibrio psychroerythrus

The red pigment of Vibrio psychroerythrus (formerly marine psychrophile NRC 1004) was identified as prodigiosin by comparison of its mass spectrum, absorption spectrum in the visible range, and chromatographic behavior with prodigiosin isolated from Serratia marcescens. The properties of the V. psychroerythrus pigment were clearly distinguishable from five other prodigiosin-like compounds isolated from three different microorganisms.     

ACTIVATION IN VITRO OF RAT LIVER POLYRIBOSOMES

The increase in the incorporation of amino acids into protein in vitro by preparations obtained from protein-fed rats as compared with preparations obtained from carbohydrate-fed rats has been described previously. After molecular sieving through Sephadex G-25 of cell-free preparations, the difference in incorporating activity between the two types of rats was diminished in systems containing ATP, phosphoenolpyruvate, pyruvate kinase, GTP, and a mixture of amino acids. When, after molecular sieving, a mitochondrial (15,000 g) supernatant was incubated for 4 min at 35°C the polysomal pattern of the preparations was unchanged. In the presence of ATP, phosphoenolpyruvate, and pyruvate kinase the polysomal incorporating activity was low and the polysomal pattern was only slightly changed. Addition of GTP increased the activity markedly, and a more pronounced activity was observed when a mixture of amino acids was added as well. As the amino acid incorporation ability increased, monosomes were formed from the polyribosomes. The activity of the polyribosomes was severalfold higher than that of non-Sephadex-treated preparations, indicating an activation of polysomal aggregates which under the usually applied conditions of incubation and prior to molecular sieving show little or insignificant activity. It was possible to activate polyribosomes from carbohydrate-fed and protein-fed rats to almost the same extent.