Activity of cholinesterases and adenosine deaminase in blood and serum of rats experimentally infected with Trypanosoma cruzi.

This study aimed to evaluate the activity of cholinesterases and adenosine deaminase (ADA) in blood and serum of rats infected with Trypanosoma cruzi. Twelve adult rats were used in the experiment divided into two uniform groups. Rodents from group A (control group) were non-infected and animals from group B served as infected, receiving intraperitoneally 3·3×10(7) trypomastigotes/each. Blood collection was performed at days 60 and 120 post-infection (PI) in order to evaluate the hemogram, blood activity of acetylcholinesterase, and serum butyrylcholinesterase and ADA activities. Hematological parameters did not differ between groups. A significant increase (P<0·05) of acetylcholinesterase activity was observed in blood while butyrylcholinesterase had a significant reduction (P<0·01) in serum of infected rats at days 60 and 120 PI. ADA activity in serum showed an inhibition in infected animals when compared to non-infected at day 120 PI. Based on these results, it is possible to conclude that the activity of cholinesterases and ADA were changed in animals infected with T. cruzi. The possible causes of these alterations will be discussed in this paper.

Activity of ectonucleotidases and adenosine deaminase in rats exposed to cigarette smoke.

Cigarette smoke is a complex mixture of various toxic substances that are capable of initiating oxidative damage and promoting blood platelet alterations. In this study, we investigated the activities of the ectoenzymes NTPDase (ectonucleoside triphosphate diphosphohydrolase, CD39) and 5'-nucleotidase (CD73) in platelets as well as adenosine deaminase (ADA) in the plasma of rats exposed to aged and diluted sidestream smoke during 4 weeks. The rats were divided into two groups: I (control) and II (exposed to smoke). After the exposure period, blood was collected and the platelets and plasma were separated for enzymatic assay. The results demonstrated that NTPDase (with ATP as substrate) and 5'-nucleotidase (AMP as substrate) activities were significantly higher in group II (p < 0.05) as compared to group I, while no significant difference was observed for NTPDase with ADP as substrate. The ADA activity was significantly reduced in group II (p < 0.05) as compared with group I. Platelet aggregation was significantly increased in group II (p < 0.05) as compared with group I. We suggest that these alterations in the activity of enzymes from the purinergic system are associated with an increase in platelet aggregation. However, our study has demonstrated that the organism tries to compensate for this enhanced aggregation by increasing hydrolysis of AMP and reducing hydrolysis of adenosine, a potent inhibitor of aggregation and an important modulator of vascular tone.

Atorvastatin increases HDL cholesterol in hypercholesterolemic patients. Evidence of a relationship with baseline HDL cholesterol.

BACKGROUND AND AIM: It has been reported that atorvastatin increases high-density lipoprotein cholesterol (HDL-C) more in patients with low than in those with high baseline HDL-C levels. This may have a biological explanation, but also suggests a statistical artifact known as the regression to the mean. METHODS AND RESULTS: Atorvastatin 10 mg/day led to a 4% increase in HDL-C after two months in 67/121 patients with hypercholesterolemia (55%), who had lower baseline HDL-C levels than the patients in whom HDL-C did not increase. In the patients with baseline HDL-C below the median, HDL-C significantly increased whereas no change was observed in patients with baseline HDL-C above the median. The correlation coefficient between pre- and post-treatment HDL-C was 0.84, thus suggesting a regression to the mean. However, the regression artifact did not entirely explain the increase in HDL-C in patients with low baseline HDL-C or the lack of an increase in those with high baseline HDL-C. The adjusted mean increase was 5.4% in patients with low pretreatment HDL-C, and 2.4% in the patients with high pretreatment HDL-C. Multiple regression analysis with the changes in HDL-C as the dependent variable showed that baseline HDL-C and the changes in serum triglycerides independently contributed to the change in HDL-C levels. CONCLUSIONS: Atorvastatin 10 mg/day increases HDL-C more in patients with low pretreatment HDL-C levels, an effect that seems to be related to the hypotriglyceridemic activity of the drug.

Effects of low doses of simvastatin and atorvastatin on high-density lipoprotein cholesterol levels in patients with hypercholesterolemia.

BACKGROUND: Simvastatin 40 to 80 mg/d has been found to increase high-density lipoprotein cholesterol (HDL-C) levels significantly more than atorvastatin at equipotent doses (ie, 20-80 mg/d). Data on the effects of lower doses of the 2 drugs on HDL-C levels are conflicting. OBJECTIVE: The purpose of this study was to investigate the effects of simvastatin 20 mg/d and atorvastatin 10 mg/d on HDL-C levels in patients with hypercholesterolemia. METHODS: Patients with primary hypercholesterolemia (total cholesterol [TC] >250 mg/dL) who were not taking any lipid-lowering agents and who were following a low-fat diet were randomized to receive 1 of 2 treatments: simvastatin 20 mg/d or atorvastatin 10 mg/d. Serum TC, triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and HDL-C levels were measured using standard methods after 2 months of therapy. In a secondary analysis, lipids and lipoprotein cholesterol were measured after 1 year in patients who continued treatment. RESULTS: Of the 240 patients enrolled (108 men and 132 women; age range, 23-77 years, mean [SEM] 56.7 [0.69]), 235 completed the study. After 2 months of therapy, TC, LDL-C, and serum TG levels decreased significantly versus baseline in both groups (P < 0.001), with no significant differences between treatment groups. HDL-C levels increased by 9.0% (P < 0.001 vs baseline) in the simvastatin group and by 4.3% (P < 0.02) in the atorvastatin group. The difference between the 2 groups in the percentage increase in HDL-C was statistically significant (P < 0.05). In 113 patients who continued treatment, HDL-C levels at 1 year were still significantly higher than baseline levels in the simvastatin group (6.3%, P = 0.034), but not in the atorvastatin group (2.8%, P = 0.587). CONCLUSIONS: The findings from this study suggest that the HDL-C-increasing effect of simvastatin 20 mg is significantly greater than that of atorvastatin 10 mg. Since increasing HDL-C levels is thought to lower the risk for atherosclerosis and coronary heart disease, these results warrant further investigation.

Serum lipoprotein profile in patients with cancer. A comparison with non-cancer subjects.

The association of cancer with low serum total cholesterol is well established. Less clear is the relationship of cancer with the cholesterol distribution among the different lipoprotein classes. Conflicting results have been reported on low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and serum triglyceride levels in different types of tumor. Total serum cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, and serum triglycerides were analyzed in 530 patients with newly diagnosed cancer (97 with hematological malignancies, 92 with tumor of the lung, 108 of the upper digestive system, 103 of colon, 32 of breast, and 98 of the genitourinary system) and in 415 non-cancer subjects. Anthropometric (body mass index) and biochemical (serum albumin) indices of nutritional status were also determined in all subjects. Total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, serum albumin, and body mass index were significantly lower in cancer than in non cancer-subjects. The lowest values of total cholesterol, low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol were recorded in patients with hematological malignancies and the highest in patients with breast tumor. All the cancer groups, with the exception of women with breast cancer, showed significantly lower total cholesterol, low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol than age- and sex-matched non-cancer subjects. Multiple regression analysis with low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, and triglycerides as dependent variables and sex, age, body mass index, albumin, and cancer (dummy variable) as independent variables, showed that cancer was independently associated with low levels of low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol and with high values of serum triglycerides. Total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, serum triglycerides, body mass index and serum albumin were significantly lower in patients with metastatic than in patients with non-metastatic solid tumor. The significant difference in low-density lipoprotein-cholesterol and serum triglycerides between patients with metastatic and non-metastatic cancer was lost when lipoprotein cholesterol and serum triglyceride levels were adjusted for nutritional variables. The lipid profile in cancer patients is characterized by low low-density lipoprotein-cholesterol, low high-density lipoprotein-cholesterol and relatively high serum triglycerides. The abnormality is a common feature of both hematological and solid tumors and is not entirely explained by poor nutrition.

Lowering effects of four different statins on serum triglyceride level.

OBJECTIVES: The main effect of statins is the decrease of serum level of low-density lipoprotein (LDL) cholesterol, due to the inhibition of intracellular cholesterol biosynthesis which brings about an upregulation of LDL receptors. A minor effect is the decrease of serum triglycerides. The present study was undertaken to verify whether all statins are effective in reducing serum triglycerides and whether their effect on triglycerides is related to the LDL cholesterol lowering activity. METHODS: Of 197 hypercholesterolaemic patients on stable low-fat low-cholesterol diet, 49 were put on atorvastatin 10 mg per day, 48 on fluvastatin 40 mg per day, 50 on pravastatin 20 mg per day and 50 on simvastatin 10 mg per day. RESULTS: After 2 months, mean percentage change in serum triglycerides and LDL cholesterol resulted to be significantly different among the four treatment groups, whereas the ratio between the percentage decrease in serum triglycerides and that of LDL cholesterol (Deltatriglyceride/DeltaLDL cholesterol ratio) was not significantly different. Only baseline serum triglycerides resulted to be significantly associated with Deltatriglycerides/DeltaLDL cholesterol ratio. All statins are then effective in decreasing triglyceride levels. CONCLUSION: The lack of a significant difference in Deltatriglycerides/DeltaLDL cholesterol ratio among the treatment groups suggests that the more effective the statin is in decreasing LDL cholesterol, the more it will also be in decreasing serum triglycerides.

The effect of simvastatin on HDL cholesterol in hyperlipidemic patients. Evidence of a relationship with the changes in serum triglyceride level.

The main effect of simvastatin is the decrease of serum cholesterol due to the reduction of LDL. A decrease of serum triglycerides and an increase of HDL-C are commonly observed during the treatment. The reduction of triglycerides is accounted for by the increased catabolism of apo B-containing lipoproteins whereas the mechanisms bringing about the increase of HDL-C are still unknown. We treated 318 patients with primary hyperlipidemia (227 with phenotype IIa and 91 with phenotype IIb) with simvastatin 10 mg a day and after 6 weeks we found a mean 3% increase in HDL-C. HDL-C increased only in about half of the patients and the patients in whom HDL-C increased had baseline higher serum triglycerides and had a greater hypotriglyceridemic response than patients in whom HDL-C did not increase. Accordingly, HDL-C increased in type IIb patients who experienced a greater change in triglycerides than type IIa patients, in whom HDL-C did not increase significantly. Apo A-I levels did not change and apo A-I/HDL-C ratio significantly decreased. At a daily dose of 40 mg, administered to 51 treatment-resistant patients, simvastatin produced a marginally greater decrease in serum cholesterol and LDL-C, but not in serum triglycerides and HDL-C, than at the daily dose of 10 mg. An increase in HDL-C was associated with a reduction in serum triglycerides. The decrease in apo A-I/HDL-C ratio suggests that the increase in HDL-C after simvastatin must be regarded as an enrichment of the cholesterol core of HDL particles. The effect is likely to be due to the decrease of the serum concentration of VLDL bringing about a reduction of cholesterol transfer from apo A-I to apo B-containing lipoproteins.

Serum cholesterol levels in patients with cancer. Relationship with nutritional status.

Epidemiological surveys indicate an inverse relationship between cancer occurrence and serum cholesterol. Low serum cholesterol might be either a risk factor for cancer or the effect of factors associated with cancer itself, such as biological properties of malignant cells, tumor mass, and poor nutritional status. We have measured serum cholesterol in 975 selected patients admitted to our hospital; 496 (272 males, 224 females) had solid tumors and 479 (253 males, 226 females) had non-neoplastic diseases. Serum cholesterol was positively correlated with body mass index, serum albumin, hemoglobin, and cholinesterase in both cancer and non-cancer subjects. Cholesterol was significantly lower in cancer patients than in age- and sex-matched non-cancer subjects. After adjustment for nutritional variables (analysis of covariance), the difference in cholesterol level between cancer and non-cancer subjects lost statistical significance in all but patients with tumors of the upper gastrointestinal tract. No difference was found in adjusted mean serum cholesterol between cancer patients subdivided according to the extension of the tumor was defined by the TNM system. In patients with solid tumors, serum cholesterol seems to be more related to the nutritional status than the presence and extension of cancer.

Effects of bezafibrate and of 2 HMG-CoA reductase inhibitors on lipoprotein (a) level in hypercholesterolemic patients.

Lp(a) level is relatively stable in each individual and is mainly under genetic control. Attempts made to lower Lp(a) with pharmacological means gave conflicting results. In order to further evaluate the effect of hypocholesterolemic drugs on Lp(a) level, 66 patients with primary hypercholesterolemia were selected. The vast majority of the patients had Lp(a) concentration at the low end of the range of distribution, 7 had undetectable Lp(a) levels and only 2 had Lp(a) higher than 30 mg/dl. No relationship was found between Lp(a) level and serum and lipoprotein lipids. In 12 patients serum cholesterol was well controlled by diet alone and the patients continued the diet for up to 8 months. The other patients were randomly subdivided into 3 groups of therapy. The first group received slow release bezafibrate 400 mg once a day, the second one pravastatin 20 mg once a day and the third one simvastatin 10-40 mg once a day. Drug therapy lasted for 8 months. At the end of the period, 22 of 29 patients treated with the 2 HMG-CoA reductase inhibitors had Lp(a) higher than baseline. The difference was statistically significant in both groups of patients. No significant change in Lp(a) was observed in diet and in bezafibrate group. Serum and LDL cholesterol significantly decreased in all the 3 drug groups. The increase in Lp(a) after the 2 HMG-CoA reductase was small enough to have negligible effects on cardiovascular risk, but raises the problem of the role of LDL receptor in the catabolism of Lp(a).

Estimation of cardiovascular risk: total cholesterol versus lipoprotein profile.

The complete lipoprotein profile is thought to give more information about the individual risk of coronary heart disease than total cholesterol alone. Although total cholesterol has a low sensitivity in the correct assessment of the risk of coronary heart disease, it may be of value in screening programs because of its low cost. In this study of 5,335 subjects, total cholesterol gave a different assessment of coronary heart disease risk (United States National Cholesterol Education Program guidelines) in 25% of subjects than the complete lipoprotein profile. Differences in risk assignment were mainly accounted for by high- and low-density lipoprotein-cholesterol (Friedewald equation). The calculated low-density lipoprotein-cholesterol was highly correlated with the value measured with a mixed ultracentrifugation and precipitation procedure. However, calculated values gave estimates of coronary heart disease risk which were 20% different from those from measure values. In 200 subjects in whom the lipoprotein profile was assessed three times in 1 year, the total cholesterol low-density lipoprotein-cholesterol varied by more than 30 mg/dl (0.78 mmol/l) in 52% and 50%, respectively, triglycerides by more than 30 mg/dl (0.34 mmol/l) in 75%, and high-density lipoprotein-cholesterol by more than 15 mg/dl (0.39 mmol/l) in 34%. Compared with the mean of the measurements, the single measurement of total cholesterol misclassified 48% of subjects, low-density lipoprotein-cholesterol 60%, high-density lipoprotein-cholesterol 12%, and 28%. We conclude that total cholesterol alone may be misleading in the assignment of coronary heart disease risk. Calculation of low-density lipoprotein-cholesterol, although less accurate than desirable, is the only way of evaluating this in clinical practice.(ABSTRACT TRUNCATED AT 250 WORDS)

[Generalized and persistent lymphadenopathy in drug addicts: clinical and epidemiological aspects]. / Linfoadenopatia generalizzata e persistente in tossicodipendenti: aspetti clinici ed epidemiologici.

Persistent unexplained lymphadenopathy with intermittent fever, weight loss, night sweats and malaise was observed in the period from March 1983 to April 1984 in 66 intravenous drug addicts living in Milan. A high percent of these subjects showed cellular immunity alterations, with significant decrease of total lymphocyte count (p less than 0.001) and of OKT4+ cells (percent and absolute number) (p less than 0.001) OKT8+ cells were augmented in percent, but not in absolute count. OKT4/OKT8 cell ratio were inverted, with significant reduction versus the healthy controls (p less than 0.001). IgG mean concentrations were significantly higher than the normal (p less than 0.001). Anergy or hypoergy to recall skin testing were evidenced in 58/66 patients. Cases of persistent unexplained lymphadenopathy associated with abnormalities of cellular immunity are considered as a possible prodrom of AIDS and were frequently observed in high risk populations. The occurrence of this clinical syndrome in a urban area may be premonitory of further progression to the epidemic. It will be necessary to assess whether this clinical and immunological picture will result in some of these patients in full blown acquired immunodeficiency syndrome.

Transient symptomatic cryoglobulinemia in gram-negative bacteria infections.

Mixed polyclonal cryoglobulinemia was observed in seven patients suffering from severe gram-negative bacterial infections and/or septicaemias and presenting with arthralgia and purpuric manifestations on admission. Cryoglobulins disappeared after recovery from infection in all of them and were never found during a longterm follow-up. In our opinion, gram-negative bacteria may induce the synthesis of cryoglobulins via a non-specific T-independent B-cell stimulation triggered by cell-wall lipopolysaccharides. This kind of infections, especially if chronic or relapsing, might play a role in the aetiology of some so-called essential mixed cryoglobulinemias.

Cryoglobulinaemia in a patient with Proteus mirabilis sepsis.

Mixed polyclonal cryoglobulinaemia was evidenced in a 49-year-old woman admitted to our hospital because of Proteus mirabilis sepsis associated with polyarthralgia and purpuric manifestations on the lower limbs. Cryoglobulins and circulating immune complexes decreased during the second week of illness and disappeared after recovery. CH50, C3 and properdin factor B, which were low during the early phase of the illness, returned to normal; C4 was normal throughout. The rapid clearance of cryoglobulins and immune complexes and the restoration of a normal complement profile might all be explained by the gradual elimination of P. mirabilis due to chemotherapeutic treatment.