Phosphorylation of casein and lysozyme by phosphorus oxychloride.
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Caseins↗
Biomedical subjects
G Matheis
Publications and source records attributed to G Matheis.
Complications of port-access cardiac surgery.
Port-Access cardiac surgery is a recent technology that is undergoing rapid development. The learning curve associated with this technique is a challenge even for the skilled and experienced cardiac surgeon. Mainly because of femoral cannulation, the use of guidewires, and working through small incisions, Port-Access cardiac surgery contains certain pitfalls that are clearly associated with the technology involved. These pitfalls currently require troubleshooting, but as the technology progresses, this may become less of an issue. Communicating these pitfalls to others is important to help others to avoid or better manage complications and to contribute to improving the technology of Port-Access techniques.
Cardiac Surgical Procedures↗
Studies of reperfusion injury in skeletal muscle: preserved cellular viability after extended periods of warm ischemia.
Four hours of complete normothermic ischemia in the rat hindlimb has been thought to produce extensive and irreversible damage and no possibility of salvage by reperfusion. This study tests the hypothesis that, in contrast to conventional wisdom, the cellular integrity is preserved after 4 hours of complete warm ischemia and control of the initial reperfusion can restore immediate contractility in these limbs. Ninety-two rat hindlimbs were isolated and 26 of the 92 did not undergo ischemia or reperfusion and served as controls. Sixty-six limbs were subjected to 4 hours of complete warm ischemia; of those 34 were assessed after the ischemic period without reperfusion and 32 were reperfused after the ischemic period. Nineteen hindlimbs were reperfused with Krebs-Henseleit buffer at a pressure of 100 mmHg to simulate embolectomy (uncontrolled reperfusion). In 13 legs a modified reperfusate at a pressure of 60 mmHg was used during the initial 30 minutes followed by an additional 30 minutes of reperfusion with 100 mmHg using Krebs-Henseleit buffer (controlled reperfusion). At the end of each experimental protocol, limbs were assessed by the following methods: muscle contraction, water content, volume, high energy phosphate content, muscle pH, effluent pH, mitochondrial function, ultrastructure, flow, and creatinkinase activity in the effluent. Data are expressed as mean +/- SEM. Significant differences were defined as probabilities for each test of p less than 0.05. Four hours of complete warm ischemia resulted in a severe reduction of adenosine triphosphate (4.0 +/- 0.8 vs 27.1 +/- 6.7 mumol/gm protein, p less than 0.001) and no contractions could be stimulated (0.0 +/- 0.0% CC). Muscle pH fell to 6.3 +/- 0.1 (p less than 0.001), and ultrastructural damage occurred (score 3.3 +/- 0.4 vs 0.8 +/- 0.1, p less than 0.002). However, there was only a slight increase in water content of the soleus muscle (78.7 +/- 0.2% vs 74.8 +/- 1.1%, p less than 0.05) without increase in limb volume (103.6 +/- 0.6% CV). In addition mitochondrial function was preserved well: mitochondrial oxidative phosphorylation capacity remained at 94% of control levels, ST3 at 93%, and ADP/O at 100% of control. Most importantly, controlled reperfusion restored immediate contractility in all limbs and was superior in all parameters investigated compared to uncontrolled reperfusion. These data support our inference that necrosis of skeletal muscle does not invariably occur after four hours of complete warm ischemia and suggest that muscle salvage by controlled reperfusion is possible after at least 4 hours of warm ischemia.
Adenosine Triphosphate↗
Extended donor criteria for heart transplantation.
The shortage of ideal donor hearts had led to an increasing number of would-be heart transplant recipients who die while on the waiting list. Therefore analogous to kidney and liver transplantation, an extension of the classical donor criteria became necessary, especially for high-urgency recipients. In a series of 121 orthotopic heart transplantations in 117 patients with a 1-year survival of 77%, the criteria for the selection of donor hearts have been gradually extended. Hearts from donors over 40 years of age but not exceeding 50 years were accepted without coronary angiography for 25 patients. There was no immediate graft failure, and the mean postoperative left ventricular ejection fraction, as assessed by radionuclide ventriculography, was normal. The incidence of late postoperative graft atherosclerosis was slightly but not significantly higher. Donor hearts with severe chest trauma, including bilateral hemothorax, rib fractures, and aortic hematoma were accepted for 11 patients. Immediate graft function was normal in all organs. In seven donors the body weight difference was more than 20%. Three patients with smaller grafts with more than 30% body weight difference had a highly complicated postoperative condition. In one patient acute graft failure was reversible with the administration of high dosages of catecholamines. In the other two patients, however, retransplantation was required because of irreversible failure. Episodes of hypotension that did not exceed 30 minutes had no substantial influence on postoperative graft function. The 1-year survival of recipients with donor grafts not complying with standard criteria was not significantly worse than the survival of patients whose grafts were selected according to the standard (76% versus 79%).(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Distribution of lung preservation solutions in parenchyma and airways: influence of atelectasis and route of delivery.
BACKGROUND: Bronchial healing remains one of the dominant issues in lung transplantation. Among other factors the quality of airway protection during lung procurement may contribute to improve bronchial healing. METHODS: Thirty-three pigs were divided into four groups: controls (n = 6), those receiving antegrade delivery of Euro-Collins solution with (n = 4) and without prostacyclin (n = 9), and those receiving retrograde delivery of Euro-Collins solution (n = 14). In addition, the atelectatic and nonatelectatic regions of the lungs from all groups were compared. After preparation and cannulation, cardioplegic solution and Euro-Collins solution for lung preservation were given simultaneously. After removal of the heart the double-lung bloc was harvested. During each experiment lungs were assessed by the following methods: dye-labeled microspheres for total and regional lung perfusion, tissue water content, pulmonary artery, left atrial and left ventricular pressures, cardiac output, lung temperature, and microscopic examination. Data were expressed as mean +/- standard error of the mean. RESULTS AND CONCLUSIONS: Our data show that (1) injection of modified dye-labeled microspheres is a useful method to determine absolute flow in lung parenchyma and airways, (2) determination of tissue water content is a simple and reproducible method to investigate the distribution of hyperosmolar lung preservation solutions, (3) atelectasis leads to a significant maldistribution of lung preservation solutions regardless of the route of delivery (0.7 +/- 0.2 versus 6.5 +/- 1.0 ml/min/gm lung wet weight, p = 0.0001) and a severe increase in water content (80.6% +/- 0.4% versus 79.0% +/- 0.5%, p = 0.024), (4) prostacyclin added to the pulmonary artery flush solution results in only a slight improvement in the distribution, and (5) retrograde delivery of Euro-Collins solution through the left atrium is technically feasible and seems to improve flow to the airways even without the addition of prostacyclin.
Animals↗