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Biomedical subjects

F Harder

Publications and source records attributed to F Harder.

At least 235 records · Page 13Linked to original sources

[Autologous spongiosa as an antibiotic carrier in the treatment of osteitis].

The treatment of osteomyelitis essentially depends on a bactericidal concentration of antibiotic in bone tissue with an appropriate spectrum. Ciprofloxacin is effective against the main organisms causing osteomyelitis (staphylococcus aureus, pseudomonas aeruginosa) at low MIC. We investigated the concentration of ciprofloxacin in human bone. After a single dose (200 mg ciprofloxacin i.v., preoperatively) the concentration in cortical bone was 6.9 +/- 0.8 mcg/g and 9.7 +/- 0.8 mcg/g in cancellous bone. In any case the concentration of ciprofloxacin exceeded the MIC for staph. aureus and pseudomonas aeruginosa. For the treatment of osteomyelitis we transferred the antibiotic bound to autologous cancellous bone grafts to the site of inflammation after surgical debridement. First clinical results are documented.

Administration, Topical↗

The effect of surgery and anesthetic agents on granulocyte-chemiluminescence in whole blood.

The effect of anesthesia and major abdominal surgery on zymosan-induced chemiluminescence (CL) of neutrophil granulocytes was evaluated. CL was measured in diluted whole blood taken at distinct intervals within the perioperative period. In addition, blood samples from healthy volunteers were supplemented with ether and halothane to investigate the in vitro effect of these agents. The phagocytosis-induced CL was not found to be depressed by anesthesia and surgery. Only at supranarcotic concentrations was CL reduced. Surgery and anesthesia, therefore, do not appear to impair this defense system significantly under the conditions of this investigation.

Abdomen↗

Impaired antipneumococcal antibody production in patients without spleens.

Fifteen splenectomised and 15 normal subjects were studied, in absence of any intentional immunisation, for pokeweed mitogen induced synthesis of antipneumococcal capsular polysaccharide antibodies in vitro by peripheral blood mononuclear cells. Results showed that removal of the spleen had caused a persistent immune deficiency of circulating B cells capable of synthesising IgM antipneumococcal capsular polysaccharide. In vitro synthesis of polyclonal IgM and IgG by peripheral blood mononuclear cells of subjects without spleens was also depressed. These defects were due to an abnormality of the B cell compartment. These data are evidence of the major role of the spleen in the control and production of a consistent part of pokeweed mitogen responsive circulating B cells and add another facet to the complex immune dysfunction of splenectomised subjects. The findings, moreover, may help in understanding the susceptibility of splenectomised people to pneumococcal sepsis and the delayed and impaired antibody response to pneumococcal vaccine.

Adult↗

Beta-adrenergic regulation of the blood lymphocyte phenotype distribution in normal subjects and splenectomized patients.

The beta-adrenergic effect on the release of immunoregulatory cells from the spleen was investigated by physical stress testing (bicycle ergometry up to submaximal work capacity) in 19 normal subjects (15 males, median 21 years) and in 10 male patients splenectomized for trauma (median 29 years). It was repeated in 6 subjects of each group during beta-blockade with 80 mg oxprenolol. Blood samples for leucocyte analysis were taken before and at the end of the test. Leucocyte subpopulations were analyzed in a cytofluorograph after staining of buffy coat cells by direct (B cells) or indirect immunofluorescence with monoclonal antibodies directed against the phenotypes of T- (Leu-1), T helper- (Leu-3a), T suppressor/cytotoxic (Leu-2a) cells and natural killer (OKM1+ lymphocytes) cells. In the controls all leucocyte subsets increased at ergometry, but B-, Leu-2a- and OKM1-cells increased more than Leu-3a cells. During beta-blockade the leucocyte changes reached only 50% of the value without treatment; the B- and Leu-2a cell mobilization was reduced more than the Leu-3a-, OKM1 cell- and monocyte changes. In splenectomized patients the proportional cellular changes were only half of those found in normal subjects, except for the Leu-3a cells which were not released. Beta-blockade during ergometry had no effect on Leu-3a cells, a similar effect on B- and Leu-2a cells as in normal subjects and a stronger effect on granulocytes, monocytes and OKM1 cells than in controls. In conclusion, the B- and Leu-2a cell mobilization from the spleen (50%) was beta-adrenoceptor dependent, while the one from other lymphoid organs was beta-adrenoceptor independent. The strongly spleen dependent Leu-3a cell changes were not beta-adrenoceptor mediated. Granulocyte-, monocyte- and OKM1 cell changes were only partly spleen dependent. The spleen independent changes however were strongly beta-adrenoceptor dependent.

Adolescent↗

Development of a chronic canine model for measurement of absorption by substrate appearance in portal venous blood.

Research in absorption physiology requires animal models which closely resemble the in vivo situation. The description of a new canine model satisfying these requirements is the objective of this report. Dogs were instrumented with indwelling portal vein and carotid artery catheters, a catheter jejunostomy and an electromagnetic flow measuring probe around the portal vein enabling continuous flow recordings. Following intrajejunal infusion of nutritive substrates in the conscious animal, absorption was measured as the product of porto-arterial substrate difference and portal venous flow. The model was validated in five mongrel dogs: (1) Catheters and flow measuring device function over several months. (2) The sensitivity of the method was evaluated following intrajejunal infusion of l-glycine-l-tyrosine and its constituent amino acids. A significant portoarterial concentration difference of both amino acids enabling quantitative measurement of absorption resulted when the peptide was infused at 4 mmoles/hour (20 mM solution, 200 ml/h). (3) Infusion of complete nutritive formulas caused a significant increase in portal venous flow whereas neither saline nor the amino acids or the peptides investigated had a comparable effect. (4) A validation experiment by implantation of a second flow probe distal to the chronically implanted device provided evidence that granulomatous tissue forming around the probe does not alter the accuracy of the flow recording. In summary, this method permits for the first time quantitative measurement of absorption by appearance rates in portal venous blood instead of by disappearance from the intestinal lumen.

Amino Acids↗

EDTA separation and recombination of epithelium and connective tissue of human oral mucosa. Studies of tissue transplants in nude mice.

A possible epithelial-mesenchymal interaction in determining epithelial histologic features of human oral mucosa was examined. The study comprised 74 biopsies of normal buccal mucosa and 54 biopsies of normal palatal mucosa. Epithelium was separated from connective tissue by the use of 1 mM ethylenediamine tetraacetate dihydrate. Self-recombined and cross-recombined epithelial and connective tissues and connective tissue sheets alone were transplanted to subcutaneous sites of nude mice. Histologic examination of cross-recombined palatal epithelium/buccal connective tissue transplants showed a change in keratinization pattern but no major change in number of epithelial cell layers as the result of connective tissue influence. Transplanted sheets of connective tissue after growth for 14 days showed that complete separation of biopsies from buccal mucosa had been obtained. However, palatal mucosa had been incompletely separated as evidenced by re-epithelialization of most of the connective tissue transplants. The consequences of the incomplete palatal epithelium-connective tissue separation are discussed.

Adolescent↗