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M Baltz

Publications and source records attributed to M Baltz.

12 recordsLinked to original sources

The effects of bone plug length and screw diameter on the holding strength of bone-tendon-bone grafts.

The effect of bone plug length and Kurosaka screw (DePuy, Warsaw, IN) diameter on graft holding strength of the bone-tendon-bone construct was determined. Random length porcine bone plugs were assigned to fixation with 7 or 9 mm Kurosaka screws. Peak load to failure was determined. There was a significant decrease in peak load to failure of the 5-mm long bone plugs compared with longer bone plugs. No difference was found between longer lengths of bone plug in either the 7- or 9-mm screw diameter groups. The 9-mm diameter screws significantly increased peak load to failure for both 1- and 2-cm bone plug lengths.

Animals↗

The response to Schistosoma bovis in normal and T-cell deprived mice.

Normal and T-cell deprived mice have been compared in their response to infection with Schistosoma bovis. The deprived mice survived longer than comparably infected, immunologically intact controls, despite an increased longevity of the adult S. bovis worms in the former animals giving rise to higher tissue egg densities. The reduced pathology in deprived mice was due to inhibition of T-cell dependent granuloma formation around tissue-bound schistosome eggs, with concomitantly decreased tissue disruption as evidenced by smaller spleens and lower circulating transaminase concentrations. These observations on S. bovis contrast with the greater morbidity and earlier mortality induced by S. mansoni in T-cell deprived mice, the latter due to an hepatotoxic potential of S. mansoni eggs that is expressed in the absence of the host immune response. The absence of hepatocyte damage around S. bovis eggs in deprived mice indicates that this schistosome lacks such a toxin, and this could explain why during S. bovis infection synthesis of the two acute-phase proteins, complement C3 and serum amyloid P-component (SAP) here seemed less T-dependent than has previously been found during S. mansoni infection of mice. In a time-course experiment the hypergammaglobulinaemia induced by S. bovis, and the specific IgG antibody response against egg antigens were significantly T-cell dependent during the early stages of patency. Similarly, in most experiments assayed once between 9 and 11 weeks after S. bovis infection, deprived mice had significantly reduced hypergammaglobulinaemias, and reduced specific IgM and IgG antibody responses against both worm and egg antigens.

Acute-Phase Proteins↗

Detection of endotoxin in mice by measurement of endotoxin-induced changes in plasma concentrations of zinc and of the acute-phase protein serum amyloid P-component.

Preparations of six bacterial endotoxins reduced plasma concentrations of zinc and increased concentrations of the acute-phase protein serum amyloid P component (SAP) in mice. The changes were sufficiently sensitive to permit use of either response in tests for endotoxin and hence for pyrogenic contamination.

Acute-Phase Proteins↗

Effect of ultraviolet radiation on production of epidermal cell thymocyte-activating factor/interleukin 1 in vivo and in vitro.

UV radiation was found to enhance the release by keratinocytes of epidermal cell thymocyte-activating factor (ETAF), a hormone-like molecule that is physiochemically identical to interleukin 1 (IL-1). This conclusion was supported by the following observations: (i) the keratinocyte cell line PAM 212 retained ETAF/IL-1-producing potential after exposure to UV radiation despite significant loss in cell viability; (ii) epidermal cells from normal and UV radiation-exposed mice were found to produce equivalent amounts of ETAF/IL-1 on a per cell basis with the density of epidermal cells in UV radiation-exposed skin being at least 5-fold above normal values; (iii) under the conditions used, ETAF/IL-1 could be detected in the serum of UV radiation-exposed, but not normal, animals; and (iv) many of the biologic consequences known to be mediated by elevations in ETAF/IL-1--i.e., neutrophilia, elevated levels of complement component 3, serum amyloid P, and plasma fibrinogen--were all observed in animals following a single UV radiation exposure. Animals subjected to chronic UV radiation showed an initial elevation in their levels of acute-phase reactants that returned to normal concentrations within 7 days. This correlates with observations made by others of a "desensitization" to ETAF/IL-1-mediated effects after chronic administration of known exogenous stimulators of inflammatory responses. Further, the UV radiation-induced desensitization took place in spite of demonstrable serum levels of ETAF/IL-1. These results suggest that the mechanism(s) responsible for desensitization is not an inhibition of ETAF/IL-1 synthesis but rather may result from inability of the target cells to perceive this endogenous mediator or to unavailability of serum-associated ETAF/IL-1 for the appropriate targets.

Amyloid↗

Effect of bacterial endotoxin on body temperature, plasma zinc and plasma concentrations of the acute-phase protein serum amyloid p component in mice.

Bacterial endotoxin and lipid A evoked dose-dependent increases in body temperature and plasma SAP concentrations and dose-dependent falls in plasma zinc concentrations in mice. The respective sensitivities of the three variables to lipid A or to whole endotoxin had the relation SAP greater than Zinc much greater than body temperature; zinc and SAP responses were evoked by less than 1 ng lipid A/endotoxin. Pretreatment with indomethacin prevented only the temperature response to lipid A. Pretreatment with dexamethasone did not affect the temperature response but diminished the zinc response and enhanced the SAP response to lipid A.

Amyloid↗

Complexity of cell interactions: analysis using antigens under Ir gene control.

The properties of three I region associated immunoregulatory factors involved in cell interactions are described. These are antigen specific T helper factor, suppressor factor produced by metabolically active T cells and genetically restricted factor, which is produced by macrophages and is involved in T helper cell induction. The use of these factors to analyse cell interactions is discussed.

Animals↗

Down regulation in B lymphocytes: low dose signals.

Picogram quantities of dinitrophenylated (DNP) dextran, a thymus-independent antigen or lipopolysaccharide, a B cell mitogen, signal down B lymphocytes to unresponsiveness. Down signals were detected by a decision test in which signaled lymphocytes were allowed one hour to react to an immunogenic pulse of DNP-dextran. Depletion of T cells or macrophages did not interfere with the generation of down signals. The signaling can proceed entirely at 4 degrees C and it its negative effect is transitory. Down signals which could be detected after 15 min at 37 degrees C were reversed by 60 min. It is suggested that down regulation by low dose antigenic signals provides a means of distinguishing background noise from true antigenic stimuli.

Animals↗

In vitro immunogenicity of trinitrophenylated bacteriophage T4. I. Lack of helper cell cooperation.

A primary immune response was obtained in vitro to trinitrophenylated bacteriophate T4 (TNP-T4) by using normal BALB/c spleen cells challenged in vitro. The primary response was limited to anti-TNP; we failed to find evidence of a primary anti-T4 response in spleen cell cultures challenged with either TNP-T4 or native T4. In vivo priming with the carrier T4 failed to enhance the subsequent in vitro response to TNP-T4 although such priming sometimes caused suppression of the anti-hapten response. The addition of excess free carrier to spleen cell cultures challenged with TNP-T4 failed to suppress the anti-tnp response. Spleen cells treated with anti-theta plus complement were unaffected in their ability to respond to TNP-T4. We conclude that TNP-T4 should be classified among the thymus independent antigens.

Animals↗

The effect of Kurosaka screw divergence on the holding strength of bone-tendon-bone grafts.

Fresh-frozen porcine knees were used to demonstrate the effects of diverging Kurosaka screw placement on linear load to failure in simulated anterior cruciate ligament reconstructions. Screws, placed anteromedially (rear-entry or tibial type) or intraarticularly (endoscopic femoral type) into each tibia, were directed at 0 degree, 15 degrees, or 30 degrees divergence angles relative to a guide wire. Grafts were axially loaded to failure to determine holding strength. Hierarchical analysis of variance was used to analyze differences between tibial side and endoscopic femoral type screw placement and the angles of divergence. Overall, the difference in pullout strength between rear-entry (or tibial side) and endoscopic femoral type fixation was shown to be statistically significant (P < 0.001). Anteromedially placed screws showed a statistically significant decrease in holding strength at 15 degrees and 30 degrees compared with 0 degree of divergence (P < 0.05). Intraarticular screw placement resulted in a statistically significant decrease in holding strength only at 30 degrees of divergence (P < 0.05). This study supports the importance of accurate screw placement within the tibia to ensure optimal interference fixation and suggests that endoscopic screw placement may offer significant added security when there are minor degrees of divergence.

Animals↗