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At least 703 records · Page 39Linked to original sources
PubMed1992

High-performance liquid chromatographic method to resolve and determine lipopolysaccharide sub-groups of Escherichia coli endotoxin in isolated perfused rat liver perfusate.

A high-performance liquid chromatographic method was developed for resolving heterogeneous preparations of fluorescently labelled endotoxin derived from Escherichia coli (Serotype 0111:B4) into separate lipopolysaccharide sub-groups. The endotoxin was chromatographed on an analytical gel permeation column using a mobile phase of acetonitrile (20%, v/v) and 100 mM phosphate buffer (pH 7.75). Four fluorescent peaks were resolved, representing sub-groups of markedly different molecular sizes. Three of the four sub-groups contained the core polysaccharide 2-keto-3-deoxyoctonate, confirming that they contained lipopolysaccharide. Fluorescein isothiocyanate (FITC)-labelled endotoxins derived from Vibrio cholerae and Salmonella minnesota chromatographed using the same system eluted with distinctly different patterns of peaks from each other and from E. coli. Extraction of E. coli FITC-endotoxin from a buffer solution using a phenol-diethyl ether method and subsequent chromatography allowed the determination of three of the four fluorescent sub-groups over the concentration range 1-15 micrograms/ml.

Animals↗
PubMed1989

Assessment of regional myocardial perfusion by contrast echocardiography. II. Detection of changes in transmural and subendocardial perfusion during dipyridamole-induced hyperemia in a model of critical coronary stenosis.

Measurements of myocardial contrast (sonicated meglumine diatrizoate) intensity were compared with myocardial flow by radioactive microspheres before and after administration of dipyridamole (0.5 mg/kg body weight intravenously) in 10 open chest dogs with a critical stenosis in the left circumflex coronary artery. Computer measurements of contrast time-intensity curves corrected for background myocardial intensity were made along 12 transmural segments of the left ventricle at mid-papillary level and for the subendocardial and subepicardial half of each segment. After administration of dipyridamole, transmural flow in the control region increased significantly (p less than 0.001), resulting in a dipyridamole/baseline flow ratio (i.e., coronary reserve ratio) of 2.54 +/- 0.95. Similar changes (p less than 0.001) were seen by contrast echocardiography; the coronary reserve ratio was 2.10 +/- 0.60 with use of peak intensity and 3.48 +/- 1.58 with use of area under the time-intensity curve. In contrast, no significant changes were observed in myocardial flow, peak contrast intensity or area under the curve in the ischemic region after dipyridamole. In the control region the ratio of subendocardial to subepicardial flow was similar at baseline and after dipyridamole administration as assessed by microspheres (1.08 +/- 0.24 versus 1.17 +/- 0.25) or by area under the time-intensity curve (1.11 +/- 0.45 versus 1.11 +/- 0.56). In the ischemic region, the subendocardial/subepicardial flow ratio decreased significantly after dipyridamole administration as measured by microspheres (1.15 +/- 0.19 to 0.82 +/- 0.25; p less than 0.001) or by area under the curve (1.10 +/- 0.28 to 0.70 +/- 0.47; p less than 0.01). Thus, myocardial contrast echocardiography appears to be a sensitive technique with which to detect changes in myocardial flow induced by dipyridamole in the various myocardial layers of normal segments as well as of segments supplied by a critically stenotic coronary artery.

Animals↗
PubMed1993

[Perioperative perfusion in children: evaluation of a new perfusion solution].

A new intravenous solution (B66) containing 0.9% dextrose in water for infusion therapy in infants and children was assessed. Forty-one children, aged between 6 months and 11 years, scheduled for elective non haemorrhagic surgery, were randomly assigned to two groups: children in group I (n = 22) were given 1% dextrose in lactated Ringer's solution (RLG1), and those in group II (n = 19) the commercially available solution B66 (0.9% dextrose in lactated Ringer's solution). The fluids were administered throughout the study with volumetric infusion pumps (IVAC 541). The infusion rate was adapted to children's weight and age. Blood samples for blood glucose, sodium and protein concentration assessments were obtained at induction (T0), on arrival in the recovery room (T1), than 30 and 60 min later (T2 and T3). Preoperative blood glucose concentrations were within the normal range for all children except for two, who had asymptomatic hypoglycaemia (2.2 and 2.3 mmol.l-1). Postoperative blood glucose concentrations were higher in both groups. This increase was significantly greater in the RLG1 group than in the B66 group. The highest mean figures at T1 were 6.8 +/- 1.5 mmol.l-1 and 5.2 +/- 1.0 mmol.l-1 in the RLG1 and B66 groups respectively. Total protein levels decreased postoperatively significantly in both groups. Preoperative age-related differences in total protein concentrations were also observed postoperatively. Sodium concentrations remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose↗
PubMed1977

[Renal perfusion during experimental hyper-acute rejection. 133-xenon perfusion compared with microscopy and angiography (author's transl)].

Twenty-two cat kidneys and 11 pig kidneys were incorporated into canine circulatory systems. The delayed hyper-acute and hyper-acute rejections produced by these models were studied with respect to blood flow and blood distribution with an intra-arterial 133-xenon wash-out technique at intervals of 7-30 minutes until the death of the kidney at 40 minutes to twelve hours. In addition, magnification angiograms and serial cortical biopsies were obtained for continuous histological study of the rejection phenomenon. At the beginning of the rejection process, there is a reduction in blood-flow through the cortex. During delayed hyper-acute rejection, cortical flow could no longer be demonstrated 180 minutes after the period of flow maximum. After A.L.G. treatment of dogs, rejection could be delayed for ten to twelve hours. Magnification angiograms showed characteristic changes consisting of irregular segmental and interlobar arteries, occlusion of small cortical vessels and focal contrast accumulation in the renal cortex. The changes in blood-flow and blood distribution measured with 133-xenon and the vascular findings on the angiogram could be correlated with the microscopic findings. Serial estimations of blood flow and blood distribution with the xenon blood wash-out technique permit differentiation between shock kidney and rejection following renal transplantation.

Acute Disease↗
PubMed2006

Early post-stress pulmonary uptake of 99mTc tetrofosmin during exercise (SPECT) myocardial perfusion imaging: correlation with haemodynamic, perfusion and function parameters.

OBJECTIVE: To test the association of early post-stress lung/heart ratio (LHR) of 99mTc tetrofosmin radioactivity with gated-SPECT findings and angiographic results. METHODS: We studied 158 consecutive patients, with stress/rest 99mTc tetrofosmin myocardial SPECT and coronary angiography. Rest scans were obtained as gated SPECT and the left ventricular ejection fraction and end diastolic volume were calculated. To evaluate myocardial ischaemia, we calculated the summed stress score, summed rest score and summed difference score indices. For the LHR calculation, we acquired an anterior image, 4-6 min after radiotracer injection at stress; LHR was defined as mean counts/pixel in the lung region of interest divided by the mean counts/pixel in the myocardial region of interest. RESULTS: An early post-stress LHR value of 0.500 was defined as the upper normal limit. The most significant correlation (P<0.001) was observed among early post-stress LHR, summed stress score and the number of stenosed vessels. The incidence of multi-vessel coronary artery disease in the subgroup of patients with increased values of early post-stress LHR, was significantly higher than in the normal group (81% vs. 42%, P<0.001). There was a significant difference (P<0.001) of the early post-stress LHR value between patients with normal coronary arteries or one-vessel disease and patients with multi-vessel disease. Early post-stress LHR was an independent predictor of multi-vessel coronary artery disease (coefficient 1.85, SD 0.16, P<0.001), with an incremental value for its identification. CONCLUSIONS: Our results suggest that early post-stress 99mTc tetrofosmin LHR appears to be a useful index of extensive myocardial ischaemia dysfunction and multi-vessel coronary artery disease.

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