Kinetically specific spin-label substrates of liver alcohol dehydrogenase and of liver aldehyde dehydrogenase.
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Alcohol Dehydrogenase↗
Biomedical subjects
E Barth
Publications and source records attributed to E Barth.
Ultrastructural quantitation of mitochondria and myofilaments in cardiac muscle from 10 different animal species including man.
The ultrastructural quantitative composition of normal myocardial cells has been studied in 10 different species: man, dog, pig, cat, rabbit, ferret, guinea-pig, rat, mouse, and bat. Volume densities of mitochondria, myofibrils, and cytoplasm were determined using morphometry. It was found that the content of mitochondria differs in various species ranging between 22.0-37.0%. It is a very specific and constant value for any particular species, the smallest having the highest content. A close correlation exists between the mitochondrial volume density, heart rate and the rate of basal oxygen consumption in any group of animals. The myofibrillar volume density shows no species variability. It was about 60.0% in all species. It is concluded that the mitochondrial volume density is a good indicator of the oxidative capacity of cardiac muscle and that the species specific normal ultrastructural myocyte composition should be a useful baseline in pathophysiological studies of the heart in various animals.
Actin Cytoskeleton↗
Multicentre evaluation of the blood gas-electrolyte-analyser "BGE".
A multicentre evaluation of the blood gas-electrolyte-haematocrit-analyser BGE (Fa. Instrumentation Laboratory), following as far as possible the ECCLS guidelines for multicentre evaluation of blood gas analysers, was performed by three laboratories. The rules of the evaluation protocol were extended to the electrolyte and haematocrit determinations. The BGE proved to be easy to operate and maintain. The stability of the measuring system was good. The within-run imprecision of all electrodes was excellent. The same applies to the between-day imprecision, except for the calcium measurements. The systematic deviation of the gas electrodes was very small. Comparison studies revealed clinically significant deviations only for ionized calcium. Some suggestions for further improvements are made.
Blood Gas Analysis↗
An analysis of polyethylene thickness in modular total knee components.
Polyethylene wear has become an important consideration in total knee arthroplasty. The actual polyethylene thickness of modular tibial components is not widely known and may be critical to long-term survival of implants. The actual polyethylene thickness of eight widely used tibial components was measured and found to vary significantly among manufacturers, even though the combined thickness of metal tray and polyethylene was similar. No component met current recommendations for minimum polyethylene thickness.
Biomechanical Phenomena↗
Fundamental limits of linear filters in the visual processing of two-dimensional signals.
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Humans↗
Animal model for evaluating bone repair with and without adjunctive hyperbaric oxygen therapy (HBO): comparing dose schedules.
The effect of hyperbaric oxygen (HBO) on the healing of standardized metaphyseal defects in the cortices of rat femurs was studied. The question was whether a known total amount of HBO given twice a day (BID) would have a different effect than once a day (QD) treatments. A microvascular casting technique was developed whereby vessel ingrowth at the repair site could be monitored using scanning electron microscopy (SEM). Bone repair morphology was evaluated by light microscopy (LM) and various tissue components were quantified by histomorphometry (HM). Animals were sacrificed 1, 2, 3, or 5 weeks postoperatively. SEM revealed that endosteal bone ingrowth was totally responsible for the repair of the cortical defects. Moreover, endosteal vessel ingrowth did not differ between controls and either group of HBO treated animals. LM displayed enchondral ossification in controls and BID treated animals and a pronounced osteoclastic activity in the latter group throughout the repair process. By contrast the QD treated group healed by primary ossification. Judged by the HM data, QD treatment appeared to accelerate bone repair and vessel ingrowth compared to controls, while BID treatment seemed to retard these processes.
Animals↗
Histologic comparison of ceramic and titanium implants in cats.
This study compared the reparative processes around cylindrical glass-ceramic-coated and pure titanium implants placed in feline femurs. Six weeks after implant placement, bone specimens with inserted implants were prepared for histologic examination including histomorphometric quantification of the relative implant surface areas that were in contact with bone. The glass-ceramic implants were surrounded by a 0.2- to 0.5-mm envelope of fibrous connective tissue [corrected]. By contrast, the major part of the titanium implants (81% +/- 5%) was in direct contact with living lamellar or woven bone. Thus, titanium and glass ceramic evoked different reparative processes when implanted in bone, and only the titanium implants appeared to become osseointegrated.
Animals↗
In vitro and in vivo comparative colonization of Staphylococcus aureus and Staphylococcus epidermidis on orthopaedic implant materials.
Clinically, Staphylococcus aureus appears to be the dominant organism associated with infected metal implants, whereas coagulase-negative staphylococcal strains are more frequently isolated from infected polymer implants. We reproduced this trend experimentally in vitro and in vivo. Discs of a titanium alloy, poly(methyl methacrylate) and ultra-high molecular weight polyethylene were exposed to a clinical isolate of Staphylococcus aureus or either of two strains of Staphylococcus epidermidis. Within 1 h Staphylococcus aureus was always the most rapid colonizer regardless of biomaterial. However, after 8 to 24 h, Staphylococcus aureus was present in higher numbers on metal and Staphylococcus epidermidis on polymers. Moreover, the exopolysaccharide produced by Staphylococcus epidermidis appeared to offer an effective protection against host defences in vivo.
Alloys↗
Implant infection.
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Bacterial Infections↗
Effects of extracellular slime produced by Staphylococcus epidermidis on oxidative responses of rabbit alveolar macrophages.
Bacterial slime produced in mass cultures of the RP 12 strain of Staphylococcus epidermidis was extracted with 4 M guanidine-HCl plus 0.05 M sodium acetate and 0.5% CHAPS, concentrated, dialyzed, and subjected to separation on DEAE sephacel columns. Three fractions, I-2A, I-2B, and I-4, were eluted with linear gradients of NaCl. Fractions I-2A and I-2B were alcian blue positive, whereas I-4 was alcian blue negative but the most electronegative fraction. The crude polysaccharide fraction and the three purified fractions were incubated individually for 2.5 or 20 h with normal rabbit alveolar macrophages (AM) to determine their effect on a subsequent PMA-induced oxidative burst. The crude fraction (50-200 micrograms/mL) and I-2B (50-200 micrograms/mL) primed the AM to give approximately a threefold increase in the PMA-induced burst after 2.5 h incubation. In contrast, a 20-h incubation resulted in a 30-40% inhibition of the PMA-induced burst with AM incubated with the same concentrations of the crude, I-2A, or I-2B fractions. Fraction I-4 had no detectable effect. The fractions also were tested to determine if they could elicit an oxidative burst in BCG-immune AM. None of the fractions (up to 500 micrograms/mL) elicited a significant oxidative burst even though BCG-immune AM yielded a PMA-induced burst 100 times that observed with normal resident AM. These data suggest that slime from S. epidermidis can impair the PMA-induced oxidative burst of normal AM during a 20-h incubation period and could explain in part why host defenses are compromised by slime-producing S. epidermidis.
Animals↗
The use of adjunctive hyperbaric oxygen in treatment of orthopedic infections and problem wounds: an overview and case reports.
We summarize indications, contraindications, and therapeutic guidelines for the use of adjunctive hyperbaric oxygen therapy (HBO) in problem wounds and selected orthopaedic infections. Three typical cases that all were successfully treated with HBO are presented: a chronic osteomyelitis which was a sequela to an open tibia fracture, a second- and third-degree burn injury of the entire lower extremity, and a case of chronic osteomyelitis in an insulin-dependent diabetic.
Adult↗
Weight-bearing porous fiber titanium implants in rat tibia: a restricted growth model for comparison of normal and pathological bone repair.
An experimental model in rats for comparison of bone repair under normal and pathological conditions is described. The low cost of rats and the simple surgical procedure used allow large-scale studies. Although clinical implications must be interpreted with care, our model may prove useful in the attempt to understand how various drugs and metabolic disorders may affect bone healing. We used porous fiber titanium implants to replace a segment of the right proximal tibia in rats. The void space to be filled with bone represented a known and constant volume allowing a direct comparison between differently treated groups. Selected parameters for bone ingrowth could be expressed in terms of growth curves as a function of time, using a mathematical equation for restricted growth. The following parameters for quantity and quality of the ingrown bone were monitored: micromoles calcium as parameter for amount; calcium/hydroxyproline molar ratio for extent of mineralization; calcium/phosphorus molar ratio for maturity of minerals; and ultimate bending stress for strength of the bone-implant interface. With this model we have studied the effect that cis-platinum, an anticancer drug that is used in the treatment of osteogenic sarcoma, has on bone repair.
Animals↗
Staphylococcal adhesion to collagen in intra-articular sepsis.
Ultrastructural studies of the cartilaginous articular surfaces of human and rabbit joints have shown that cartilage is the target substratum for adhesion by Staphylococcus aureus, leading to intra-articular sepsis. Transmission and scanning electron microscope studies demonstrated bacteria in intimate contact with acellular cartilage matrix surfaces, particularly with collagen fibres. Certain strains of Staphylococcus aureus used in these experiments reveal a high binding capacity to collagen that is derived from a cartilage matrix. These studies indicate that the pathogenesis of intra-articular sepsis is based on the ability of certain strains of staphylococci to bind preferentially to a cartilage matrix.
Animals↗
Comparison of bone reactions to coated tricalcium phosphate and pure titanium dental implants in the canine iliac crest.
Titanium and TCP-coated implants were compared after insertion in the canine iliac crest. Observation time was 14 wk. Evaluation included pull-out tests, energy dispersive X-ray analysis, and histologic examination of in situ, undemineralized implants. The TCP-coated implants were more firmly attached to bone than were the titanium implants. The calcium/phosphorus ratios around the titanium implants were higher than around the TCP-coated implants. Both types of implants were closely surrounded by bone after a 14-wk implantation.
Animals↗
Chemiluminescent responses of macrophages exposed to biomaterials: a biocompatibility screening test.
Chemiluminescence (CL) response of alveolar macrophages (AM) exposed to either phagocytosable or nonphagocytosable particles of polymethylmethacrylate (PMMA) or titanium in vitro was monitored. The results were correlated to known in vivo bone tissue compatibility of the materials. Moreover, the quantity and morphology of adherent AM on titanium and PMMA disks were assessed using scanning electron microscopy (SEM). Our results with PMMA indicated that a high CL response to phagocytosable as well as nonphagocytosable particles of the biomaterial in question, correlated with poor bone tissue compatibility. By contrast, a low CL response to phagocytosable particles and no response to nonphagocytosable particles correlated with a satisfactory bone tissue compatibility, as in the case of titanium. SEM showed 48% more AM adherent to PMMA than titanium per unit area. Also, the percentage of cells with membrane damage was three times higher on PMMA than on titanium. It appears that the CL response of AM exposed to biomaterials in vitro thus can be used as an easy to do screening test for potential orthopaedic implant materials before in vivo tests are considered.
Animals↗
Effects of acetylsalicylic acid on intramuscular bone matrix implants and composite grafts in rats.
Antigen-extracted, autolyzed, demineralized bone matrix and bone matrix combined with isogeneic bone marrow (i.e., a composite graft) were placed in the musculature of young male rats. The influence of acetylsalicylic acid (ASA) on the osteogenic potential of these bone-inducing materials was studied during an 18-day period. ASA (150 mg/kg/12 h) was used to obtain anti-inflammatory serum levels comparable with those in humans. Resorption of the implanted matrix and new formation of bone were quantified using collagen- and mineral-tracing radioisotopes and collagen and calcium analyses. The matrix implants showed a slow tissue turnover and produced only small amounts of new bone, with no significant differences between ASA-treated and control rats. However, during the last 24 h of the study the ASA-treated implants had a significantly hampered rate of new bone formation. The tissue turnover and new bone yield, as well as the rate of new bone formation, increased in the control composite grafts but not in the ASA-treated composite grafts. Thus, the results indicate an inhibitory effect of ASA on the bone-forming capacity of bone marrow.
Animals↗
[Seasonal variations in the incidence of acute anterior uveitis].
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Acute Disease↗