The interaction between lipopolysaccharide (LPS) and rat erythrocyte membranes was studied in vitro. The incubation of erythrocytes with LPS isolated from E. coli (J5 mutant) resulted in a decrease in membrane fluidity as determined by spin-label, electron spin resonance, and in the inhibition of Na+, K+-ATPase activity without remarkable alteration of the membrane lipid composition. The generation of hydroxy radicals was detected by spin-trap, electron spin resonance in the erythrocyte/LPS incubation medium. We suggest that changes in the dynamic properties of erythrocyte membranes were mediated by LPS itself and not indirectly by changes in the membrane lipid composition.
A novel method for the microquantitative simultaneous determination of lactate and pyruvate in blood plasma and urine is described. The principle of the assay is to determine lactate after its enzymatic conversion to pyruvate followed by the derivatization of the latter into fluorescent 2-hydroxy-3-methylquinoxaline (QXL) and determination of it by reversed-phase high-performance liquid chromatography (HPLC). The complete conversion reaction mixture was optimized, preincubated with lactate dehydrogenase for 5min at 37°C, and deproteinized by the tungstic acid precipitation method. The supernatant was subjected to derivatization into QXL and then analyzed by HPLC. The present method is accurate and reproducible, and lactate can be measured up to 1, 200nmol in the conversion mixture. We also confirmed that the method is applicable for use in the clinical diagnosis of patients with acidemia, giving results in reasonably good agreement with those obtained by other conventional methods.
It is well known that there is present in hemolyzed serum a factor that interferes with the radioimmunoassay for detection of skeletal muscle carbonic anhydrase III (CA-III) in serum. This inhibitory factor cross-reacts with muscle anti-CA-III antibody and its level increases in parallel with the degree of hemolysis. In order to identify this factor, we purified the factor from a hemolysate of human erythrocytes, characterized it, compared it with known carbonic anhydrase isozymes from erythrocytes and with CA-III from skeletal muscle. We concluded that the factor was biochemically and immunochemically identical to CA-III from skeletal muscle. Calculation indicated the factor to represent about 1% of the total enzymes in human erythrocytes.
In an animal model of aging, the accelerated senescence-prone (SAM-P/1) mouse, we found the deposition of lipofuscin and elastic fibers in the skin of 12-month-old animals of this strain. The deposition was most remarkable in the dorsal neck and head skin. Taking into account our previous data that the lipid peroxide level in the dorsal neck and head skin significantly increases prior to the appearance of the age-related signs in these areas of the skin, we propose that the increased lipid peroxides would cause the deposition of not only lipofuscin but also elastic fibers in the skin of SAM-P/1 mouse.
Epinephrine and norepinephrine, when either formed a complex with iron, were able to induce lipid peroxidation in rat liver microsomes. The microsomal lipid peroxidation induced by them was NADPH-dependent. Adrenochrome, an oxidation product of epinephrine, was also able to induce microsomal lipid peroxidation in the presence of iron, but in this case it was mainly NADPH-independent. Catecholamines can be deleterious to biological systems, if they form complexes with iron and thus induce lipid peroxidation to some extent.
The present study comprised 22 normal subjects and 30 bilharzial patients. The patients were categorized into groups I, II, and III according to the stage of liver affection and the absence or presence of ascitis. Total plasma alkaline phosphatase (AP) was assayed by use of the substrate naphthyl phosphate, and the liver isoenzyme activity of AP was also investigated after treatment of the plasma with L-phenylalanine, which inhibits the AP fraction of intestinal origin (LPSAP). The activity measured in the presence of L-phenylalanine thus represents that attributable to plasma AP of liver origin. Respective mean activities of 47 and 41 and 78 and 72 units/liter were obtained for total and AP isoenzyme of liver origin in the plasma of normal and bilharzial patients with hepatosplenomegaly and ascitis (group III), respectively. The liver fraction represented 87.2 and 92.3% of total plasma AP among normal and bilharzial patients (group III), respectively.
In this study, serum and ascites total protein, albumin, lactate dehydrogenase, alkaline phosphatase, gamma-glutamyl-transpeptidase enzyme activities, and serum and plasma fibronectin levels were determined in patients with cirrhosis (n=39) and in those with different types of malignancies (n=23). In malignant ascites, ascitic fluid protein levels were increased 3.3 times when compared with the levels in the cirrhotic ascites. The levels of the ascitic fluid lactate dehydrogenase compared with the serum levels were found to be significantly different (p<0.001). In cirrhotic and malignant ascites, alkaline phosphatase values were 21±16units/liter and 75±71units/liter, respectively (p<0.001). Fibronectin concentrations of the patients with malignancy were increased 2 times as compared with those of cirrhotic patients (p<0.001). The correlations between ascitic fluid fibronectin levels and total protein levels were found to be moderately significant. These results suggest that fibronectin levels together with the protein levels, lactate dehydrogenase, alkaline phosphatase, and gamma-glutamyl-transpeptidase enzyme activities may be used for the differential diagnosis of ascites.
This study aimed at clarifying the relationship between iron status and atherogenic lipid profile in normal and chronic rheumatic heart as well as congenital heart defect children. The study included 31 children, 16 cases with chronic rheumatic heart disease (10 males and 6 females) and 6 with congenital heart disease. Nine children with normal hearts were taken as the control. Serum iron and total iron binding capacity were higher in both chronic rheumatic and congenital heart disease children than in the controls; but the increase was only significant in the second case. Serum low-density lipoprotein cholesterol (LDL-ch) and high-density lipoprotein-cholesterol (HDL-ch) were not significantly changed in either disease. In relation to sex, no significant changes were noticed in iron status of chronic rheumatic heart children. Serum LDL-ch and LDL-ch to HDL-ch ratio were significantly higher in females than in males. A correlation study was also done between lipid profile and iron status.
This study examined the physical status (72 males and 69 females) and serum distribution of lipids, protein, and Ca (60 males and 57 females) of people aged 1 to 72 years living in southeastern Nepal. The mean values of height and weight increased with age to adolescence and were the same for both sexes in childhood. Males were taller than females above the 15-19-year age group. There were large weight differences among individuals, with adult males tending to be heavier than adult females. The average body mass index increased with age (r=0.72, p<0.001), and there were no significant differences between the sexes. The levels of body mass index were positively correlated with weight (r=0.92, p<0.001) and with serum levels of cholesterol and triglycerides (r=0.43, and r=0.38, p<0.001, respectively). The levels of serum lipids were about the same for both sexes in childhood and tended to be higher for males than for females in adulthood. Serum levels of cholesterol, phospholipids, and total lipids were positively correlated with age (r=0.46, r=0.36, and r=0.37, p<0.001, respectively). A direct relationship was found between the levels of cholesterol and triglycerides (r=0.46, p<0.001). The mean levels of protein and Ca in serum were similar for both sexes for all ages examined (7.82 and 8.02g/100ml for protein and 10.6 and 10.3mg/100ml for Ca, for males and females, respectively). The protein levels showed a correlation with Ca (r=0.30, p<0.001). Based on the above findings, we conclude that the Nepalese tend to have higher serum levels of TG and to have serum protein and Ca levels similar to what is considered the normal range for inhabitants of developed countries.