Archive for April, 2011
Posted by James
Organism
The isolate of P aeruginosa used in this study to induce endocarditis has been described in detail elsewhere. The MBC of this strain as determined in cation-supplemented Mueller-Hinton broth for amikacin is 2ug/ml, while that for gentamicin and tobramycin is 1 ug/ml.
Endocarditis
The details of the catheterization and induction of aortic endocarditis in rabbits have been published previously. Briefly, a transcarotid catheter is passed across the aortic valve to induce sterile endocarditis on the leaflet. Pseudomonal endocarditis is produced 24 hours after catheterization by injecting about 10 cfu of saline-washed cells intravenously. Positive blood cultures for P aeruginosa 24 hours after inoculation serve as presumptive evidence of the induction of bacterial endocarditis. In the present study the model of endocarditis was used to assess densities of infected aortic vegetations.
Read the rest of this entry »
Posted by James
Therapeutic outcomes in humans with aortic valve endocarditis remain relatively poor, particularly with virulent valvular pathogens (eg, Staphylococcus aureus and Pseudomonas aeruginosa). Aminoglyco- side-based regimens have not had a major salutary impact on the outcomes of treatment of these latter endocarditides, despite in vitro susceptibilities of these bacterial strains to such agents. This subopti- mal efficacy of aminoglycosides in human endocarditis has suggested potential impairment in either intravegetation penetration or distribution of these agents within cardiac vegetations.
Read the rest of this entry »
Posted by James
Serum total LD was elevated in all three groups of patients and there was much overlapping between the three groups (Fig 4). This enzyme system was not capable of differentiating the groups from one another. These findings agree with our previous experimental results which suggest that LD may be only minimally elevated by acute bowel infarction but other conditions (such as myocardial infarctions or major aortic reconstruction) can cause elevations above the upper limits of normal for this enzyme.
The ratio of LD/LD/2 was quite capable of differentiating patients with AMI from patients with acute bowel infarctions and patients undergoing major AAS (Fig 5). The only patients who had LD,/LD2 ratios greater than 1.00 were those who had electrocardio- graphically proven AMI. None of the patients in the other two groups had this isoenzyme change in any of the serum samples evaluated. Other clinical conditions which can cause this change in LD/LD2 ratio are renal infarction and hemolysis of blood samples. These conditions can be differentiated from acute bowel infarction or myocardial infarction on a clinical basis.
Read the rest of this entry »
Posted by James
Previous experimental studies have shown that mesenteric infarction causes an elevation of serum total С К within the first 24 hours after an infarction. The three isoenzymes of С К also become elevated within that same time period. The majority of the enzyme elevation is CK-MM, with CK-MB and CK- BB being present but being substantially less than the amount of CK-MM present. Clinical evaluation of the CK tracings in the patients that had MES INF showed that these patients had elevations of serum total С К in the first 24 hours as did the patients who had major aortic reconstructions and AMI. All three groups went above the upper limit of normal (100 IU/L) for our laboratory within this time frame. Differentiation between these three groups of patients based on this measurement was not possible.
Read the rest of this entry »
Posted by James
Determination of the serum CK-MB in international units per liter showed that there were minimal elevations in the group of patients that had major aortic reconstruction; however, the groups that had AMI or MES INF showed marked elevations within the first three days after their clinical events (Fig 3). Maximum values for CK-MB (IU/L) were reached approximately 16 to 24 hours after the clinical events in both those groups. There were fairly marked variations in the amount of CK-MB present within these groups. The patients with necrotic bowel and those with myocardial infarctions could not be differentiated one from another based on these measurements alone on day 2 and day 3 following the onset of their clinical events.
Read the rest of this entry »
Posted by James
Patient groups consisted of 15 patients admitted to the coronary care unit who were diagnosed as having an acute transmural myocardial infarction confirmed by serial ECGs. There were 13 patients identified with bowel necrosis. The patients with AMI and those undergoing major aortic reconstructions all had serum samples drawn as noted. Those patients who had bowel necrosis had fewer samples drawn because patients were taken to the operating room or died early in their hospital course as a result of the bowel infarction. Six patients with bowel necrosis had isoenzyme determinations of LD and С К subsequent to their bowel infarctions. Two other patients had advanced so far into their clinical courses of severe bowel infarction that their enzymes were deemed unreliable for isoenzyme analysis. These two patients had profound hypoperfusion syndromes which promoted generalized decrease in perfusion of the entire body with resulting enzyme release from many organs. Only one patient subsequently survived a bowel infarction (Table 1).
Read the rest of this entry »
Posted by James
Three groups of patients were studied. The first consisted of 15 patients who were admitted to the coronary care unit with electrocardiographic evidence of acute transmural myocardial infarctions. These patients had serum samples drawn for isoenzyme analyses every eight hours starting with admission for the first 24 hours of their hospital course. Samples were then drawn daily for five days for isoenzyme analyses of both CK and LD. In the second group, 13 individuals who were to undergo elective aortobifemoral bypass grafts for either occlusive or aneurysmal disease were studied. These patients had normal preoperative ECGs and serum isoenzyme analyses. Postoperatively, serum samples were collected for isoenzyme determinations in the recovery room and twice daily for three days. Samples were subsequently collected daily for an additional five days. During the first two postoperative days, the patients were monitored in the surgical intensive care unit and serial ECGs were performed daily. The third group of patients consisted of eight individuals with suspected bowel infarction. Confirmation of mesenteric infarction was obtained at operation or at autopsy in all cases. Enzyme determinations were drawn preop- eratively and postoperatively at least twice daily until both С К and LD returned to normal. These patients also had daily electrocardiographic monitoring postoperatively to determine whether myocardial infarction had occurred. All blood samples were centrifuged for ten minutes at 3,000 rpm. Serum was extracted from each sample using standard pipettes. Serum total CK and LD were determined by automated spectrophotometry. Isoenzymes were determined using agarose gel electrophoresis. Results for each measurement were tabulated, compiled and graphed. Perceived differences were evaluated by the Wilcoxon rank-sum test to determine whether they were significant between groups. All values reported are values from the normal distribution reflecting an analysis of a one-sided test.
Read the rest of this entry »