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Biomedical subjects

R Benner

Publications and source records attributed to R Benner.

At least 217 records · Page 12Linked to original sources
PubMed1976

Antibody formation in mouse bone marrow. V. The response to the thymus-independent antigen Ecsherichia coli lipopolysaccharide.

The occurrence of plaque-forming cells (PFC) in mouse bone marrow was studied during primary and secondary responses to the thymus-independent antigen Escherichia coli lipopolysaccharide (LPS). Anti-LPS responses were induced by various doses of LPS. During the primary response, doses of 1 and 10 mug LPS intravenously (i.v.) were found to evoke a distinct PFC response in both spleen and bone marrow. The spleen contained the majority of PFC until about 5 days after immunization. During the course of the reaction the number of PFC in the bone marrow rose to a level which equalled or surpassed the level in the spleen. LPS doses of 0-001, 0-01 and 0-1 mug i.v. only induced a PFC response in the spleen. Apparently there is a minimal threshold dose of LPS of about 1 mug for PFC to appear in the bone marrow. The secondary response was studied in mice primed with 1 mug LPS i.v. and boosted with either 0-001, 0-1 or 10 mug LPS i.v. 3 months later. After each dose tested the PFC activity in the spleen was several times higher than during the primary response. As was observed in the primary response doses of 0-001 and 0-1 mug LPS i.v. did not evoke a PFC response in the bone marrow. After boosting with 10 mug of LPS i.v. a significant PFC response was found in spleen, bone marrow, thymus, lymph nodes, Peyer's patches and blood. From about 5 days after the booster injection the number of PFC in the bone marrow exceeded the total number found in all other lymphoid organs. The results are discussed in relation to the bone marrow PFC response to the thymus-dependent antigen sheep red blood cells. To this antigen a clear PFC response in the bone marrow is found only during the secondary response.

Animals↗
PubMedDate not supplied

The effect of cyclophosphamide on B cells and 'background' immunoglobulin-secreting cells in mice.

The influence of cyclophosphamide (CY) was studied on the B-cell compartment of mice. This was done at five different levels: (a) the serum immunoglobulin (Ig) levels; (b) the numbers of 'background' Ig-secreting cells; (c) the incidence of surface Ig+ B cells; (d) the capacity of lipopolysaccharide-reactive B cells to give rise to a polyclonal IgM- and IgG-response in vitro; and (e) the capacity of long-lived memory B cells to give rise to an adoptive anti-sheep red blood cell plaque-forming cell response in vivo. A single injection of 300 mg CY/kg body weight (BW) decreased the numbers of background IgM-, IgG- and IgA-secreting cells in spleen, bone marrow and lymph nodes to minimum values of about 25% of normal at day 7. The incidence of surface Ig+ B cells also gradually decreased after CY treatment. The functional capacity of the B cells, however, was completely abolished one day after a single injection of 300 mg CY/kg BW. This was found for the lipopolysaccharide-reactive B cells, which largely represent newly formed, short-lived B cells as well as for long-lived memory B cells. The decrease of background Ig-secreting cells following a single injection of 300 mg CY/kg BW was followed by a gradual recovery with a substantial overshoot peaking about 40 days after CY injection. After multiple injections of 100 mg CY/kg BW, the minimum values of background Ig-secreting cells in the various lymphoid organs were lower than after a single injection of 300 mg CY/kg BW, but in this case the recovery was not associated with an overshoot reaction. Remarkably, the serum Ig levels were less profoundly affected than the numbers of Ig-secreting cells in the various lymphoid organs.

Animals↗
PubMedDate not supplied

Alloantigen-specific suppressor t cells can also suppress the in vivo immune response to unrelated alloantigens.

Delayed-type hypersensitivity (DTH) to both major histocompatibility complex (H-2) and non-H-2-coded antigens can be induced by subcutaneous immunization with allogeneic lymphoid cells in the mouse. While subcutaneous immunization with allogeneic cells preferentially induces DTH reactivity, intravenous immunization, especially with irradiated allogeneic cells, induces a state of suppression. Suppression is manifest both in direct host-versus-graft (HvG) assays and under graft-versus-host (GvH) conditions, where spleen cells of suppressed mice are used to reconstitute irradiated allogeneic hosts. The suppression is mediated by T cells. We have now studied the specificity of the suppressive effect by subcutaneous immunization of 'suppressed' mice with a combination of alloantigens comprising the antigen(s) used to induce the suppressor T cells as well as unrelated alloantigens. We report here that reaction against the third party alloantigens was effectively suppressed, provided these antigens were presented in combination with the antigen(s) that had induced the suppressor T cells. Both sets of alloantigens do not need to be physically associated.

Animals↗
PubMedDate not supplied

Exfoliative dermatitis due to immunologically confirmed carbamazepine hypersensitivity.

A 6-year-old Caucasian girl experienced a generalized erythematous skin rash during carbamazepine therapy. Over the next four days the eruption worsened into erythroderma with fever and generalized lymphadenopathy. Routine laboratory studies revealed increased serum levels of liver enzymes and eosinophilia. Immunologic reactivity to the anticonvulsant carbamazepine and its analogs was investigated both in vivo and in vitro by patch tests and lymphocyte proliferation assays, respectively.

Alanine Transaminase↗
PubMedDate not supplied

Characterization and origin of dissolved organic carbon in Yegua ground water in Brazos County, Texas.

Dissolved organic carbon (DOC) concentrations in five shallow (< 20 m) and three deeper wells (27 to 30 m) in the Eocene Yegua Formation (Brazos County in east-central Texas) ranged from 92 to 500 microns. Characterization of high, intermediate, and low molecular weight DOC fractions (HMW > 3000 amu, IMW 1000 to 3000 amu, and LMW 500 to 1000 amu) and combined neutral sugar analyses provide information on organic matter sources in the Yegua aquifers. Combined neutral sugars ranged in concentration from 0.6 to 2.7 mumol/L and comprised 0.8% to 6.7% of DOC in ground water. Glucose was the most abundant neutral sugar, followed by xylose and galactose, arabinose, mannose, rhamnose, and fucose. These combined neutral sugars were more diagenetically altered in shallow, oxic ground water as indicated by high mole % fucose + rhamnose and low neutral sugar yield. The precursors for neutral sugars are most probably angiosperm leaves, which show a similar distribution pattern of neutral sugars. Ground water DOC was depleted in 13C relative to soil-zone organic matter (OM) (-16@1000 to -19@1000). The delta 13C values of bulk DOC and HMW DOC ranged from -24@1000 to -32@1000, whereas LMW and IMW DOC ranged from -32@1000 to -34@1000 and -16@1000 to -28@1000, respectively. This variability in delta 13C values is probably related to microbial processes and selective preservation of OM. Carbon isotope analyses in bulk and different molecular weight DOC fractions imply a predominantly C3 OM source and a low contribution of soil-zone OM to DOC.

Carbon↗
PubMedDate not supplied

Stories from the front lines.

When expert nurses are freed to practice nursing in the way they know is good, with others who care about positive patient outcomes, in a supportive environment, they will want to stay in that work setting and that setting will attract others of like mind. How to begin? With storytelling.

Anecdotes as Topic↗
PubMedDate not supplied

The involvement of T1 and T2 lymphocytes in primary and secondary delayed type hypersensitivity responsiveness.

The contribution of short-lived and long-lived T lymphocytes (T1 and T2 lymphocytes respectively) to primary and secondary delayed type hypersensitivity (DTH) responsiveness was studied by means of thymectomy of adult mice (ATx) with sheep red blood cells as the antigen. Within one month after ATx a fall of the primary and secondary DTH responsiveness was found of 20% and 50% respectively. This reduction can be attributed to the loss of short-lived T cells. ATx 8 months prior to the administration of the priming dose caused a decrease of the primary and the secondary DTH responsiveness of about 50% and 65% respectively. These data suggest that both the short-lived T1 and the long-lived T2 precursor cells account for the occurrence of (1) cells mediating the primary DTH response and (2) memory cells responsible for the secondary DTH response. The contribution of both populations of precursor cells in primary and secondary DTH responsiveness appeared to be only proportionally different.

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