Search PubMed⌕ Search

Biomedical subjects

A Syrota

Publications and source records attributed to A Syrota.

At least 163 records · Page 9Linked to original sources
PubMed1981

Significance of intra- and extrahepatic portasystemic shunting in survival of cirrhotic patients.

Survival and incidence of hemorrhage and encephalopathy were studied in 121 medically managed cirrhotic patients according to the type of naturally occurring portasystemic shunting. Three types of shunting were distinguishable using scintillation splenoportography, a method whereby morphological and hemodynamic data on portal and hepatic circulation were obtained by external detection. The three patterns were: (1) extrahepatic shunting with partial splenic blood flow diversion, (2) spontaneous total splenic blood flow diversion, and (3) intrahepatic shunting corresponding to portohepatic communications with a diameter larger than 10 mum. The probability of 4-year survival was much lower in case of portasystemic shunting (18%) than in its absence (73%, P less than 0.01). Patients with intrahepatic shunting had a survival rate not significantly different from that of patients with extrahepatic shunting. However, they had the highest incidence of hemorrhage (71%), and hemorrhage was not due to rupture of esophageal varices. The highest incidence of encephalopathy was seen in patients with total splenic blood diversion (40%), but it was not significantly different from that of other cirrhotic patients. No group of patients can be significantly identified as a high-risk group.

Humans↗
PubMed1981

11C-L-methionine for evaluation of pancreatic exocrine function.

Pancreatic uptake of a natural amino acid, L-methionine, was measured in 58 patients using a scintillation camera. This was possible by labelling L-methionine with 11C, a short-lived isotope produced in a cyclotron. Time-activity-curves obtained in areas of interest selected over the pancreas in 25 normal subjects and in 14 alcoholic patients showed a plateau or a slight increase of activity with time. In contrast, in 19 patients with chronic pancreatitis an initial increase in radioactivity was followed by a decrease for 10 to 20 minutes and then by a plateau. The ratio of the height of the plateau at the 50th minute to the height of the peak was 0.74 +/- 0.21 in these patients, whereas it was 0.96 +/- 0.09 in the other subjects (P less than 0.001). This result was compared with direct measurements of 11C radioactivity and of amylase and bicarbonate in duodenal aspirate. The median amount of 11C incorporated into protein at the 70th minute was 53% of total activity in the control group, 28% in alcoholic patients, and only 3% in chronic pancreatitis, the differences between these values were highly significant. The absence of a peak of radioactivity in the duodenal juice, and the existence of a correlation between total 11C output and amylase output suggested that there was no release of protein in the duodenum in chronic pancreatitis. These results also suggested that the peak observed by external detection could be due to amino acid back-diffusion from the pancreas into the blood. External detection with 11C-L-methionine could be used for the assessment of pancreatic dysfunction in man.

Adult↗
PubMed1981

Pulmonary extraction of C-11 chlorpromazine, measured by residue detection in man.

Uptake of C-11 chlorpromazine (CPZ) was measured to evaluate the nonrespiratory function of lung in patients. A multiple-indicator dilution technique was used with external detection. Following intravenous bolus injection of C-11 CPZ, with In-113m transferrin as an intravascular reference molecule, counts were recorded with a scintillation camera using two energy windows. The residue functions, R(t), for C-11 CPZ and In-113m transferrin were plotted against time for selected areas of interest, and the CPZ area-weighted extraction, E(t), was computed for the same areas every 250 msec using the formula: E(t) = [RT(t) - RR(t)]/[1 - RR(t)], where RT and RR are the normalized residue functions for CPZ and transferrin, respectively. The initial extraction was 90 +/- 5% in four normal subjects and 64 +/- 7% in six patients with chronic obstructive lung disease (C.O.L.D.), these values being significantly different (p less than 0.001). The large initial extraction of CPZ in a single passage through the pulmonary vasculature resulted from a fixation to membranes, due to its high liposolubility. The lower extraction seen in patients with C.O.L.D. was explained by weaker fixation to lung tissue.

Binding Sites↗
PubMed1979

[A fast transient osmotic method. Simultaneous in vivo determination of the reflexion coefficient and of the permeability/filtration coefficient ratio of the pulmonary capillary endothelium in the dog].

Thermodynamic variables characterizing the transport of water and urea across Dog pulmonary capillary membrane were obtained in vivo by means of a pulse transient osmotic method. Results were inconsistent with the hypothesis of a homoporous membrane. When data were interpreted in terms of an exclusive water channel and of a shared pore pathway, the value of the pore reflexion coefficient was close to zero for urea.

Animals↗
PubMed1979

[A fast osmotic transition method for the study of pulmonary transcapillary exchange: theoretical model].

A theoretical model allowed the simultaneous determination of the reflexion coefficients of capillary membrane to small hydrophilic molecules and of the ratios of their permeability to filtration coefficient. This was applied to dilution curves obtained after injection of a hypertonic solution containing a vascular tracer. The calculated variables did not depend on the capillary exchange surface area.

Capillaries↗
PubMed1979

[11C]methionine pancreatic scanning with positron emission computed tomography.

By the use of [11C]methionine and positron computed tomography (PCT), images of the pancreas were obtained in 32 patients. The injection of between 10 and 20 mCi of this product enables four to six transverse sections to be obtained. Seventeen of the patients studied had no exocrine pancreatic disease, and in all these cases the pancreas was clearly visible. In four cases of pancreatic carcinoma and one of retroperitoneal tumor, there were abnormalities visible. In five cases of chronic pancreatitis, no pancreatic uptake was observed. In a sixth case, concentration was visible, but only in the head of the pancreas. One case of acute pancreatitis, which showed no concentration during the acute phase, returned to normal after recovery. When visible, the pancreas was easily located and distinguishable from the intestinal image, except in two cases that were uninterpretable for technical reasons. No false positive or negative was observed, but a differential diagnosis between cancer and pancreatitis was impossible.

Carbon Radioisotopes↗
PubMed1978

Infinite dilution conductimetry of plasma and urine: correlation with osmolality.

The infinite dilution conductivity (IDC) of plasma and urine allows a measurement of the electrolyte content in small samples (5 to 15 microliter). The method was compared to the corrected osmolality (II'p) measured by the freezing-point depression. A linear correlation existed between II'p and the IDC: for plasma: II'p = 13.10 sigma o,p + 37.00 (n = 46 and r = 0.9949) for urine: II'u = 12.75 sigma o,u + 16.56 (n = 85 and r = 0.9504). The measurement of the IDC does not depend on protein concentration and can be used instead of the osmometer methods to determine the total plasma and urine electrolyte content.

Blood Physiological Phenomena↗
PubMed1976

Scintillation splenoportography: hemodynamic and morphological study of the portal circulation.

The intrasplenic injection of 99mTc-labeled albumin microspheres, followed 30 sec later by an injection of 99mTc-labeled red blood cells with recording of the progression of the two tracers, were performed in 110 patients. This also enabled the plotting of activity versus time curves on splenic, hepatic, cardiac, and pulmonary areas of interest, there by giving access to several hemodynamic variables. Scintillation image demonstrated splenoportal obstruction in 8 cases. Intrahepatic obstruction with reflux via collaterals were observed in 53 cases, 14 with umbilical reflux. In 13 cases, the patency of surgical portacaval anastomoses were verified. The splenoportal blood flow velocity was not significantly different in patients with cirrhosis (V = 10.1 cm per sec +/- 3.0 SD) and in normal subjects (V = 13.2 cm per sec +/- 5.8 SD). The fraction of shunted splenic flow in the case of cirrhosis varied from 0 to 100%; there was no relationship between this percentage and the seriousness of the clinical status. In 3 cases, the presence of intrahepatic shunts was detected. There was a very significant difference between mean transit time (MTT) of red blood cells in patients with cirrhosis (t = 12.2 sec +/- 4.4 SD) and those without cirrhosis (t = 19.9 sec +/- 3.7 SD). Among patients with cirrhosis, those with a history of jaundice had a shorter MTT than those without such a history. On the other hand, the MTT was not significantly different whether the patients with cirrhosis had or did not have hemorrhage, ascites or encephalopathy. There was a positive correlation (P less than 0.01) between MTT and plasma albumin concentration,and between MTT and prothrombin (P less than 0.01). Finally, there was a high negative correlation (P less than 0.001) between MTT and total serum bilirubin. Scintillation splenoportography is a useful technique for assessing hepatic hemodynamics and for demonstrating abnormalities of the intrahepatic circulation.

Blood Flow Velocity↗