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Biomedical subjects

E Rivera

Publications and source records attributed to E Rivera.

At least 109 records · Page 6Linked to original sources
PubMed1984

Interferon fever: absence of human leukocytic pyrogen response to recombinant alpha-interferon.

A sensitive in vitro assay for generation of human leukocytic pyrogen has been used to study the pathogenesis of fever accompanying administration of human alpha-interferon. Unlike other potent pyrogens, two recombinant interferon preparations tested over a wide concentration range did not stimulate release of leukocytic pyrogen. This result suggests that interferon may cause fever by a novel mechanism not dependent on leukocytic pyrogen.

Animals↗
PubMed1984

A non-haemagglutinating isolate of mink enteritis virus.

A virus was isolated from mink showing clinical and pathological signs of mink enteritis. This virus was identified as mink enteritis virus (MEV) from results of serological tests, determination of its density in CsCl (1.415 g cm-3), and morphology, including size (20 nm in diameter). The isolate was designated MEV-S. In contrast to other known MEV strains, the MEV-S isolate has no haemagglutinating (HA) activity with swine red blood cells (RBCs) at 4 degrees C and pH 6.8. Neither was there any HA at other pH values and temperatures, or when horse, bovine and rhesus monkey RBC's were used.

Animals↗
PubMed1981

Clinical observations on group composition tested by simulated groups in the laboratory.

Examined the effect of the presence of a model (our confederate) on the subsequent success or failure of Ss in 3-person groups to effect a plan of behavioral change with regard to assertion deficits. For half the groups, the model expressed warmth, for half the absence of warmth (coldness). For half of each of these she was successful in effecting her change plan; for half she was not successful. Ss clearly distinguished warm from cold models, but only marginally differentiated successful from failure models. Warmth in the person of the model was found to be a significant determinant of S behavioral change. The results and enthusiastic S participation suggest that this paradigm deserves further study.

Assertiveness↗
PubMed1979

Limulus amebocyte lysate testing of nomral serum albumin (human) in the United States since 1975.

In order to determine the reactivity of Limulus Amebocyte Lysate to albumin products, over 1500 lots of 25% Normal Serum (Human) produced by 12 U.S. licensed manufacturers were tested over the past 4 years. Representative samples of 5% Normal Serum Albumin (Human) and Purified Protein Fraction (human) were also tested with Limulus Amebocyte Lysate. Problems associated with apparent false negative reactions are discussed. Model test protocols are presented that might be useful in determining the degree of false positivity of albumin products. These models could be adopted by blood fractionators to gather validation data to support substitution of the Limulus Amebocyte Lysate test for the rabbit pyrogen test.

Animals↗
PubMed1975

In vitro response of lymphocytes to Micropolyspora faeni extract in cattle.

The in vitro stimulation of small lymphocytes to blast formation, measured by the rate of 3H-thymidine incorporation, was used to study the occurrence of cells sensitive to antigens of Micropolyspora faeni in cattle. M faeni extract induced a significant stimulation index in lymphocytes from the peripheral blood cells of cattle from an endemic area in autumn but rarely in spring. Blood lymphocytes from animals from a non-endemic area tested during the winter period rarely showed a positive reaction or only a relatively weak one. On the other hand, lymph node cells, particularly from bronchial lymph nodes, showed positive results in all investigated animals and even in those from non-endemic areas. In three-months-old calves, positive results were obtained mainly with cells from bronchial lymph nodes. It seems therfore that sensitisation to M faeni antigen is a widespread phenomenon but additional circumstances seem to be required for the clinical manifestation of farmer's lung disease in cattle. The most important factor is probably strong and repeated exposure to the M faeni organism. Whether or not existing reactive lymphocytes against M faeni antigen are directly involved in the pathogenesis of farmer's lung disease in cattle by producing a delayed type reaction remains to be clarified.

Animals↗
PubMed1970

Lecithin Biosynthetic Enzymes of Onion Stem and the Distribution of Phosphorylcholine-Cytidyl Transferase among Cell Fractions.

Enzymatic activities of the cytidine 5'-diphosphate choline pathway for lecithin biosynthesis were demonstrated in homogenates of onion stem (Allium cepa). Choline kinase activity was present in the postmicrosomal supernatant, with less than 3% sedimenting with the particulate fractions. Phosphorylcholine-cytidyl transferase was distributed among all fractions, and phosphorylcholine-glyceride transferase was predominantly found in the particulate fraction.The phosphorylcholine-cytidyl transferase activity of onion stem required a divalent ion (Mg(2+) or Mn(2+)) for activity, was inhibited by Ca(2+), and was specific for cytidine triphosphate, with optimal activity in the range pH 6 to 7. To evaluate the distribution among cell fractions, conditions of pH, cofactors, substrate, and assay were optimized for each fraction. One-third of the transferase activity sedimented with the mitochondria-proplastids fraction, and one-third was in the microsomal supernatant. The dictyosome fraction contained about 10% of the total activity but showed a greater specific activity than the other fractions. Similar results were obtained with homogenates from rat liver, in that purified Golgi apparatus fractions contained the highest phosphorylcholine-cytidyl transferase activity on a protein basis when compared with other cell fractions at pH 7.2.

Journal Article↗