Fatal perinatal sarcocystosis in a lamb

A 3-wk-old lamb died because of neurological disease. The predominant microscopic lesions were in the brain and spinal cord and consisted of nonsuppurative encephalomyelitis with severe gliosis throughout the gray and white matter. Immature and mature schizonts, 15.7 x 10.6 microns (8-30 x 6-18 microns), occurred in capillaries and were structurally similar to those of Sarcocystis tenella.     

Hierarchy of cytotoxic T cell clones. II. Intraclonal triggering of lysis by hapten-specific CTL

Cells from clones of anti-hapten murine cytotoxic T lymphocytes (CTL) can act as both target and effector cells, but will not lyse members of the same clone. The effect of haptenation on the cytolytic activity of anti-fluorescein (FL) and anti-trinitrophenol (TNP) CTL clones was examined. Treatment of anti-FL clones with fluorescein isothiocyanate or anti-TNP clones with trinitrobenzene sulphonic acid induces these clones to kill in an antigen-independent fashion. Targets killed by the haptenated CTL included syngeneic and allogeneic B lymphocyte blast cells, P815, YAC-1 and in one case human GM 4072 tumor cells. The importance of CD8 and T cell receptor (TCR) occupancy is demonstrated by the ability to block autotriggering by antibody directed against Ly 2 and the TCR. The results demonstrate that effects other than antigen recognition of the target play a role in the final outcome of effector-target cell interactions and provide a mechanism which could lead to autodestruction and immunosuppression particularly in some types of viral infection.     

Solubility characteristics of Micrococcus lysodeikticus membrane components in detergents and chaotropic salts analyzed by immunoelectrophoresis

In order to evaluate the effectiveness and selectivity of various reagents in the solubilization of bacterial membranes, membranes of Micrococcus lysodeikticus were treated with detergents and chaotropic agents. The composition of the extracts so obtained was analyzed by rocket and two-dimensional immunoelectrophoretic techniques. Recovery of succinate-, malate-, and reduced nicotinamide adenine dinucleotide- (NADH) dehydrogenases, ATPase, succinylated lipomannan and cytochromes in the extracts was measured. Treatment with a variety of non-denaturing detergents produced extracts that were generally qualitatively uniform although quantitative differences were observed. The degree of extraction of various components was correlated with the hydrophile-lipophile balance. Several chaotropic agents were also evaluated as reagents for membrane solubilization. These agents were less effective in extraction of bulk protein, but produced extracts enriched in some membrane components.     

Effect of acute exposure to 3660 m altitude on orthostatic responses and tolerance.

Orthostatic reflexes were examined at 375 m and after 60 min of exposure in a hypobaric chamber at 3660 m using a 20-min 70 degrees head-up tilt (HUT) test. Mean arterial blood pressure, R wave-R wave interval (RRI), and mean cerebral blood flow velocity (MFV) were examined with coarse-graining spectral analysis. Of 14 subjects, 7 at 375 m and 12 at 3660 m were presyncopal. Immediately on arrival to high altitude, breathing frequency and MFV increased, and endtidal PCO2, RRI, RRI complexity, and the parasympathetic nervous system indicator decreased. MFV was similar in HUT at both altitudes. The sympathetic nervous system indicator increased with tilt at 3660 m, whereas parasympathetic nervous system indicator decreased with tilt at both altitudes. Multiple regression analysis of supine variables from either 375 or 3660 m and the time to presyncope at 3660 m indicated that, after 1 h of exposure, increased presyncope at altitude was the result of 1). ineffective peripheral vasoconstriction, despite increased cardiac sympathetic nervous system activity with HUT, and 2). insufficient cerebral perfusion owing to cerebral vasoconstriction as the result of hypoxic hyperventilation-induced hypocapnia.     

Effect of phenolic acids and phenolics from plant cell walls on rumenlike fermentation in consecutive batch culture

Information on the interaction between mixed populations in the rumen and plant phenolics is required to fully elucidate the limitations of phenolic compounds on forage digestibility. The objective of this study was to examine the degradation of Italian ryegrass (Lolium multiflorum L.) hay incubated with mixed ruminal populations in consecutive batch culture (CBC) with or without phenolic acids or phenolic compounds extracted from plant cell walls. Each CBC consisted of a series of 10 cultures (3 replicates per culture) inoculated (10%, vol/vol) in sequence at 48-h intervals with microbial suspension from the previous set of cultures. All cultures were grown on a semidefined medium containing Italian ryegrass hay, and each CBC was initiated with an inoculum from the rumen. Rumenlike fermentation characteristics were maintained in control CBCs by repeated inoculum transfer. Treatment CBCs were transferred as described above, but cultures 5, 6, and 7 were incubated in the presence of trans-p-coumaric, cis-p-coumaric, or trans-ferulic acid or phenolics extracted from the cell walls of maize stem or barley straw. Mean apparent dry matter disappearance in control CBC cultures was 495 mg per g of hay, whereas the presence of phenolics reduced the initial dry matter disappearance by 6.3 to 25.6%. trans-p-Coumaric acid and, to a lesser extent, the phenolics from cell walls of maize stem were the most inhibitory compounds for dry matter disappearance and for the production of volatile fatty acids; trans-p-coumaric acid altered the molar ratio of acetate/propionate/butyrate. The CBC further showed variations in the ability of the rumen microbial population to adapt to phenolic compounds.