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Biomedical subjects

G Hohlbach

Publications and source records attributed to G Hohlbach.

67 records · Page 4Linked to original sources
PubMed1985

Changes in acid-base status, lactate concentration and purine metabolites during reconstructive aortic surgery.

Hypoxanthine has been proposed as a better indicator of hypoxic damage than acid-base status or lactate. Acid-base status, lactate and purine metabolites were therefore measured in 17 patients undergoing aortic surgery. Blood samples were taken systemically just before aortic clamping and after declamping, and from the femoral vein after declamping. The systemic hypoxanthine levels increased threefold after declamping, due to 20 times higher hypoxanthine concentration in the femoral vein. The percentage changes in concentration of hypoxanthine correlated well (r = 0.85) with the aorta-clamping time. The changes in acid-base status and lactate levels were erratic and showed no correlation with the duration of the ischemic period.

Acid-Base Equilibrium↗
PubMed1983

[Validity of different methods for reducing tension of anastomoses following circular resection of the trachea].

In 23 corpses different methods to decrease tension over tracheal anastomosis after circular resection were investigated. Starting tracheal resection underneath the first tracheal ring and employing forward flection of the head, cervico-mediastinal mobilization, dissection of the lung hilus, supra-hyoidal larynx mobilization, and implantation of the left main bronchus into the bronchus intermedius, 78% of the whole trachea could be resected. Resecting the thoracic trachea from the level of its bifurcation in direction to the larynx and employing all methods for mobilization the maximum length of resection decreased by 20%, since larynx mobilization and hilus dissection had no effect.

Biomechanical Phenomena↗
PubMed1983

[Changes of the acid-base status, serum lactate concentration and purine metabolism in reconstructive arterial surgery].

Hypoxic damages are normally determined by acid-base status as well as lactate and pyruvate levels. Since several other illnesses lead also to raised levels of these parameter, they are not specific for tissue hypoxia. In animal experiments it was shown that purine metabolites, especially hypoxanthine, are a very exact indicator for hypoxia. To test its validity in clinical situations the changes in acid-base status, lactate, pyruvate and purine metabolism were measured in 17 patients undergoing reconstructive aortic surgery. Blood samples were taken just before and after declamping of the aorta systemically and from the femoral vein. After declamping especially the systemic hypoxanthine levels increased 3 fold, due to a 20 times higher hypoxanthine concentration in the femoralis vein. The concentration changes of hypoxanthine in percent correlated very good with the aorta clamping time (R = 0,85). The changes in acid-base status and lactate levels were erratic and showed no correlation with the duration of ischemic period. Systemic hypoxanthine concentrations are a more specific and reliable parameter for hypoxic damages.

Acid-Base Equilibrium↗
PubMedDate not supplied

[Experimental results of cartilage abrasion with an excimer laser. Histologic and electron microscopy studies].

Experiments carried out with cadaver cartilage from the tibiaplateau were performed using an excimer-laser to demonstrate its use for cartilage removal. Laser applications resulted in a cartilage ablation depending on energy density and the number of applied pulses. Observations made using scanning electron-microscopy showed the influence of the pulse rate on the surface structure. Transmission-electron-microscopical investigation showed the existence of a superficially altered layer with a depth of approx. 6 microns. On the basis of the results obtained, the conclusion can be reached that application of excimer-lasers for cartilage removal in a view of future endoscopic surgery could become a valuable alternative to the existing methods in the therapy of osteoarthritis.

Cartilage, Articular↗
PubMedDate not supplied

Laparoscopic fluorometry: a new minimally invasive tool for investigation of the intestinal microcirculation.

The aim of this study was to develop and establish a new system of laparoscopic fluorometry for the purpose of investigating the intestinal microcirculation. In 25 pigs (German Landrace, 16-25 kg body weight), ischemia was established in two segments (A, irreversible; B, reversible ischemia; C, internal control) of the small intestine by a laparoscopic technique. Microcirculation in the segments was assessed by laparoscopy at a second-look operation 24 h later by means of the fluorescence system Endoscan. The fluorescence of the three bowel segments was measured by arbitrary dye fluorescence units (DFU) 15 min after starting reperfusion, before and after injection of sodium fluorescein (NaFlu, 0.25 mg/kg body weight). The dividing line between viable and nonviable bowel tissue was established from the inflow and outflow rates of NaFlu with the aid of ROC (receiver operating characteristic) curves. The specificity and sensitivity of the new method were evaluated by correlating the results with the viability of each intestinal segment as predicted by three laparoscopically experienced surgeons and by histological examination. By means of the calculated separation sharpness (fluorescence index at 2 min >0.5, outflow factor of NaFlu at 10 min >20%), the overall predictions of intestinal viability in all 25 animals achieved a sensitivity of 93.5% and a specificity of 94.1% by laparoscopic fluorometry, versus a sensitivity of 70.8% and a specificity of 87.5% for the prediction of bowel viability by ordinary laparoscopic technique. Used as an adjunct to conventional laparoscopy, laparoscopic fluorometry brought significant gains in sensitivity and specificity in the distinction between reversible and irreversible intestinal ischemia.

Animals↗