Elevated levels of erythrocyte-conjugated dienes indicate increased lipid peroxidation in schistosomiasis mansoni patients

Schistosoma mansoni causes liver disease by inducing granulomatous inflammation. This favors formation of reactive oxygen species, including superoxide ions, hydrogen peroxide and hydroxyl radicals all of which may induce lipid peroxidation. We have evaluated lipid peroxidation in 18 patients with hepatosplenic schistosomiasis mansoni previously treated with oxamniquine followed by splenectomy, ligature of the left gastric vein and auto-implantation of spleen tissue, by measuring levels of erythrocyte-conjugated dienes and plasma malondialdehyde (MDA). Age-matched, healthy individuals (N = 18) formed the control group. Erythrocyte-conjugated dienes were extracted with dichloromethane/methanol and quantified by UV spectrophotometry, while plasma MDA was measured by reaction with thiobarbituric acid. Patient erythrocytes contained two times more conjugated dienes than control cells (584.5 ± 67.8 vs 271.7 ± 20.1 µmol/l, P < 0.001), whereas the increase in plasma MDA concentration (about 10%) was not statistically significant. These elevated conjugated dienes in patients infected by S. mansoni suggest increased lipid peroxidation in cell membranes, although this was not evident when a common marker of oxidative stress, plasma MDA, was measured. Nevertheless, these two markers of lipid peroxidation, circulating MDA and erythrocyte-conjugated dienes, correlated significantly in both patient (r = 0.62; P < 0.01) and control (r = 0.57; P < 0.05) groups. Our data show that patients with schistosomiasis have abnormal lipid peroxidation, with elevated erythrocyte-conjugated dienes implying dysfunctional cell membranes, and also imply that this may be attenuated by the redox capacity of antioxidant agents, which prevent accumulation of plasma MDA.

Normal expression of IFN-gammaR in four patients with uncommon mycobacterial infection phenotypes

Several primary immunodeficiency diseases affecting the interleukin 12/interferon gamma (IFN-gamma) pathway have been identified, most of them characterized by recurrent and protracted infections produced by intracellular microorganisms, particularly by several species of mycobacteria. In the present study we analyzed the expression of IFN-gamma receptor (IFN-gammaR) and signal transducer and activator of transcription 1 (STAT-1) in 4 children with Mycobacterium tuberculosis infection of uncommon clinical presentation. These molecules were evaluated by flow cytometry and Western blotting in B cells transformed with Epstein-Barr virus and mutations were scanned by single-strand conformational polymorphisms and DNA sequencing. The expression of IFN-gammaR1 was normal in all 4 patients. The genetic analysis of IFN-gammaR1 and IFN-gammaR2 coding sequences did not reveal any mutation. The expression of the STAT-1 molecule was similar in patients and healthy controls; however, when the phosphorylation of this transcription factor in response to IFN-gamma activation was evaluated by Western blot, a significant lower signal was evident in one patient. These data indicate that there are no alterations in the expression or function of the IFN-gammaR chains in these patients. However, the low level of STAT-1 phosphorylation found in one of these patients might be explained by a defect in one of the molecules involved in the signal transduction pathway after IFN-gamma interacts with its receptor. In the other three patients the inability to eliminate the mycobacteria may be due to a defect in another effector mechanism of the mononuclear phagocytes.

Response to an oral calcium load in nephrolithiasis patients with fluctuating parathyroid hormone and ionized calcium levels

the response to an oral calcium load test was assessed in 17 hypercalciuric nephrolithiasis patients who presented elevated parathyroid hormone (PTH) irrespective of the ionized calcium (sCa2+) levels. Blood samples were collected at baseline (0 min) and at 60 and 180 min after 1 g calcium load for serum PTH, total calcium, sCa2+, and 1.25(OH)2D3 determinations. According to the sCa2+ level at baseline, patients were classified as normocalcemic (N = 9) or hypercalcemic (N = 8). Six healthy subjects were also evaluated as controls. Bone mineral density was reduced in 14/17 patients. In the normocalcemic group, mean PTH levels at 0, 60 and 180 min (95 ± 76, 56 ± 40, 57 ± 45 pg/ml, respectively) did not differ from the hypercalcemic group (130 ± 75, 68 ± 35, 80 ± 33 pg/ml) but were significantly higher compared to healthy subjects despite a similar elevation in sCa2+ after 60 and 180 min vs baseline in all 3 groups. Mean total calcium and 1.25(OH)2D3 were similar in the 3 groups. Additionally, we observed that 5 of 9 normocalcemic patients presented a significantly higher concentration-time curve for serum PTH (AUC0',60',180') than the other 4 patients and the healthy subjects, suggesting a primary parathyroid dysfunction. These data suggest that the individual response to an oral calcium load test may be a valuable dynamic tool to disclose a subtle primary hyperparathyroidism in patients with high PTH and fluctuating sCa2+ levels, avoiding repeated measurements of both parameters.

Cytokine profile and nitric oxide levels in sera from patients with brucellosis

The aims of this study were to investigate the serum levels of some cytokines [tumor necrosis factor-alpha (TNF-alpha), interleukin 1ß (IL-1ß), IL-2R, IL-6, and IL-8] and nitric oxide (NO) levels in patients with untreated brucellosis and to test the correlation of these parameters with each other. The study was conducted on 67 subjects, 37 patients with brucellosis and 30 healthy individuals with no history of Brucella infection. Brucellosis was identified by a positive blood culture and/or increased Brucella antibodies in serological tests in addition to compatible clinical symptoms. Cytokine profile analysis was performed by the immulite chemiluminescent enzyme immunometric assay whose inter- and intra-assay coefficients of variance were 2.6-3.6 and 4.4-8.5%, respectively. The levels of nitrites/nitrates, which are representative of NO levels, were measured by the Griess method. Patients with brucellosis had significantly elevated serum levels of nitrites/nitrates, IL-2R, IL-6 and IL-8 (mean ± SD, 102.8 ± 23.8 µmol/l, 806.1 ± 58.5 U/ml, 21.1 ± 2.3 pg/ml, and 8.8 ± 1.6 pg/ml, respectively) compared to healthy controls, whereas TNF-alpha and IL-1ß levels were unchanged. No statistically significant correlation was detected between any of the studied cytokine levels and nitrate/nitrite concentrations according to Pearson's linear correlation test. We conclude that only IL-6, IL-8 and IL-2R are elevated in brucellosis and the extent of elevation depends on the severity and clinical pattern of the disease. Moderate elevation in serum NO was comparable to that observed in previous studies. This explains the absence or very rare occurrence of septic shock in brucellosis.

Humoral response to low molecular weight antigens of Mycobacterium tuberculosis by tuberculosis patients and contacts

Much effort has been devoted to the identification of immunologically important antigens of Mycobacterium tuberculosis and to the combination of target antigens to which antibodies from serum of tuberculous patients could react specifically. We searched for IgG antibodies specific for antigens of 45 to 6 kDa obtained after sonication of the well-characterized wild M. tuberculosis strain in order to detect differences in the antibody response to low molecular weight antigens from M. tuberculosis between patients with pulmonary tuberculosis and contacts. Specific IgG antibodies for these antigens were detected by Western blot analysis of 153 serum samples collected from 51 patients with confirmed pulmonary tuberculosis. Three samples were collected from each patient: before therapy, and after 2 and 6 months of treatment. We also analyzed 25 samples obtained from contacts, as well as 30 samples from healthy individuals with known tuberculin status, 50 samples from patients with other lung diseases and 200 samples from healthy blood donors. The positive predictive value for associated IgG reactivity against the 6-kDa and 16-kDa antigens, 6 and 38 kDa, and 16 and 38 kDa was 100% since simultaneous reactivity for these antigens was absent in healthy individuals and individuals with other lung diseases. This association was observed in 67% of the patients, but in only 8% of the contacts. The humoral response against antigens of 16 and 6 kDa seems to be important for the detection of latent tuberculosis since the associated reactivity to these antigens is mainly present in individuals with active disease.

Effect of hepatitis C serology on C-reactive protein in a cohort of Brazilian hemodialysis patients

Hepatitis C (HCV) is not an uncommon feature in hemodialysis (HD) patients and may be a cause of systemic inflammation. Plasma cytokine interleukin-6 (IL-6) is mainly produced by circulating and peripheral cells and induces the hepatic synthesis of C-reactive protein (CRP), which is the main acute phase reactant. The aim of this study was to investigate the influence of HCV on two markers of systemic inflammation, serum CRP and IL-6, in HD patients. The study included 118 HD patients (47% males, age 47 ± 13 years, 9% diabetics) who had been treated by standard HD for at least 6 months. The patients were divided into two groups depending on the presence (HCV+) or absence (HCV-) of serum antibodies against HCV. Serum albumin (S-Alb), plasma high sensitivity CRP (hsCRP), IL-6, and alanine aminotransferase (ALT) were measured and the values were compared with those for 22 healthy controls. Median hsCRP and IL-6 values and hsCRP/IL-6 ratio were: 3.5 vs 2.1 mg/l, P < 0.05; 4.3 vs 0.9 pg/ml, P < 0.0001, and 0.8 vs 2.7, P < 0.0001, for patients and controls, respectively. Age, gender, S-Alb, IL-6 and hsCRP did not differ between the HCV+ and HCV- patients. However, HCV+ patients had higher ALT (29 ± 21 vs 21 ± 25 IU/l) and had been on HD for a longer time (6.1 ± 3.0 vs 4.0 ± 2.0 years, P < 0.0001). Moreover, HCV+ patients had a significantly lower median hsCRP/IL-6 ratio (0.7 vs 0.9, P < 0.05) compared to the HCV- group. The lower hsCRP/IL-6 ratio in HCV+ patients than in HCV- patients suggests that hsCRP may be a less useful marker of inflammation in HCV+ patients and that a different cut-off value for hsCRP for this population of patients on HD may be required to define inflammation.

Hemochromatosis (HFE) gene mutations in Brazilian chronic hemodialysis patients

Patients with chronic renal insufficiency (CRI) have reduced hemoglobin levels, mostly as a result of decreased kidney production of erythropoietin, but the relation between renal insufficiency and the magnitude of hemoglobin reduction has not been well defined. Hereditary hemochromatosis is an inherited disorder of iron metabolism. The importance of the association of hemochromatosis with treatment for anemia among patients with CRI has not been well described. We analyzed the frequency of the C282Y and H63D mutations in the HFE gene in 201 Brazilian individuals with CRI undergoing hemodialysis. The analysis of the effects of HFE mutations on iron metabolism and anemia with biochemical parameters was possible in 118 patients of this study (hemoglobin, hematocrit, ferritin levels, transferrin saturation, and serum iron). A C282Y heterozygous mutation was found in 7/201 (3.4%) and H63D homozygous and heterozygous mutation were found in 2/201 (1.0%) and 46/201 (22.9%), respectively. The allelic frequencies of the HFE mutations (0.017 for C282Y mutation and 0.124 for H63D mutation) did not differ between patients with CRI and healthy controls. Regarding the biochemical parameters, no differences were observed between HFE heterozygous and mutation-negative patients, although ferritin levels were not higher among patients with the H63D mutation (P = 0.08). From what we observed in our study, C282Y/H63D HFE gene mutations are not related to degrees of anemia or iron stores in CRI patients receiving intravenous iron supplementation (P > 0.10). Nevertheless, the present data suggest that the H63D mutation may have an important function as a modulating factor of iron overload in these patients.

Residence of liquids in the infra-junctional portion of the proximal stomach in patients with gastroesophageal reflux disease

Patients with gastroesophageal reflux disease may have disturbances of gastric motility, which could play a role in the pathophysiology of the disease. Recent studies have suggested that the gastric region just below the gastroesophageal junction may have a distinct physiological behavior. We determined whether patients with gastroesophageal reflux disease have abnormal residence of food in the infra-junctional portion of the stomach after ingesting a liquid nutrient meal. Fasted adult patients with reflux disease (N = 11) and healthy volunteers (N = 10) ingested a liquid meal (320 ml; 437 kcal) labeled with 99m technetium-phytate and their total gastric emptying half-time and regional emptying from the stomach infra-junctional region were determined. In 8 patients, episodes of postprandial acidic reflux to the esophagus were measured for 2 h using pH monitoring. There were no differences between reflux patients and controls regarding total gastric emptying time (median: 68 min; range: 39-123 min vs 65 min and 60-99 min, respectively; P > 0.50). Food residence in the infra-junctional area was similar for patients and controls: 23% (range: 20-30) vs 27% (range: 19-30%; P = 0.28) and emptying from this area paralleled total gastric emptying (Rs = 0.79; P = 0.04). There was no correlation between residence of food in the infra-junctional area and episodes of gastroesophageal reflux (Rs = 0.06; P = 0.88). We conclude that it is unlikely that regional motor disturbances involving the infra-junctional region of the stomach play a relevant role in the pathogenesis of acidic gastroesophageal reflux.

Human T-cell lymphotropic virus type I (HTLV-I) proviral DNA viral load among asymptomatic patients and patients with HTLV-I-associated myelopathy/tropical spastic paraparesis

To evaluate the human T-cell lymphotropic virus type I (HTLV-I) proviral DNA load among asymptomatic HTLV-I-infected carriers and patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), real time PCR using TaqMan probes for the pol gene was performed in two million peripheral blood mononuclear cells (PBMC). The albumin gene was the internal genomic control and MT2 cells were used as positive control. The results are reported as copies/10,000 PBMC, and the detection limit was 10 copies. A total of 89 subjects (44 HAM/TSP and 45 healthy HTLV-I-infected carriers) followed up at the Institute of Infectious Diseases "Emilio Ribas" and in the Neurology Division of Hospital of Clínicas were studied. The asymptomatic HTLV-I-infected carriers had a median number of 271 copies (ranging from 5 to 4756 copies), whereas the HAM/TSP cases presented a median of 679 copies (5-5360 copies) in 10,000 PBMC. Thus, HAM/TSP patients presented a significantly higher HTLV-I proviral DNA load than healthy HTLV-I carriers (P = 0.005, one-way Mann-Whitney test). As observed in other persistent infections, proviral DNA load quantification may be an important tool for monotoring HTLV-I-infected subjects. However, long-term follow-up is necessary to validate this assay in the clinical setting.

Effect of polymorphisms of the MTHFR and APOE genes on susceptibility to diabetes and severity of diabetic retinopathy in Brazilian patients

Diabetes mellitus (DM) is a highly prevalent complex genetic disorder. There has been a worldwide effort in the identification of susceptibility genes for DM and its complications, and the 5-10-methylenetetrahydrofolate reductase (MTHFR) and apolipoprotein-E (APOE) genes have been considered good candidate susceptibility genes to this condition. The objectives of the present study were to determine if the 677T MTHFR and epsilon2/epsilon3/epsilon4 APOE alleles are risk factors for DM and for severity of diabetic retinopathy (DR). A total of 248 individuals were studied: 107 healthy individuals and 141 diabetic patients (46 with type 1 diabetes and 95 with type 2 diabetes), who also had DR (81 with non-proliferative DR and 60 with proliferative DR). The polymorphisms were analyzed by PCR followed by digestion with restriction enzyme or the single-nucleotide primer extension method. No evidence of association between the 677TT genotype of MTHFR gene and DM [cases: TT = 10/95 (10.6%); controls: TT = 14/107 (13%)] or with severity of DR was observed [cases: TT = 5/60 (8.5%); controls: TT = 9/81 (11.1%); P > 0.05]. We also did not find evidence of an association between APOE alleles and proliferative DR (epsilon2, epsilon3 and epsilon4 in cases: 9, 76, and 15%, and in controls: 5, 88, and 12%, respectively) but the carriers of epsilon2 allele were more frequent among patients with type 2 DM and DR than in controls [cases: 15/95 (15.8%); controls: 7/107 (6.5%); P < 0.05]. Therefore, our results suggest that the epsilon2 allele/APOE might be a risk factor for diabetes in the Brazilian population.

A new model for the population pharmacokinetics of didanosine in healthy subjects

Didanosine (ddI) is a component of highly active antiretroviral therapy drug combinations, used especially in resource-limited settings and in zidovudine-resistant patients. The population pharmacokinetics of ddI was evaluated in 48 healthy volunteers enrolled in two bioequivalence studies. These data, along with a set of co-variates, were the subject of a nonlinear mixed-effect modeling analysis using the NONMEM program. A two-compartment model with first order absorption (ADVAN3 TRANS3) was fitted to the serum ddI concentration data. Final pharmacokinetic parameters, expressed as functions of the co-variates gender and creatinine clearance (CL CR), were: oral clearance (CL = 55.1 + 240 x CL CR + 16.6 L/h for males and CL = 55.1 + 240 x CL CR for females), central volume (V2 = 9.8 L), intercompartmental clearance (Q = 40.9 L/h), peripheral volume (V3 = 62.7 + 22.9 L for males and V3 = 62.7 L for females), absorption rate constant (Ka = 1.51/h), and dissolution time of the tablet (D = 0.43 h). The intraindividual (residual) variability expressed as coefficient of variation was 13.0%, whereas the interindividual variability of CL, Q, V3, Ka, and D was 20.1, 75.8, 20.6, 18.9, and 38.2%, respectively. The relatively high (>30%) interindividual variability for some of these parameters, observed under the controlled experimental settings of bioequivalence trials in healthy volunteers, may result from genetic variability of the processes involved in ddI absorption and disposition.

Erythrocyte phosphoglucomutase activity of bipolar I patients currently using lithium or carbamazepine

Lithium has been used for the last five decades to treat bipolar disorder, but the molecular basis of its therapeutic effect is unknown. Phosphoglucomutase is a key enzyme in the metabolism of glycogen. In yeast, rabbit and human HEK293 cells, it is inhibited by lithium in the therapeutic concentration range. We measured the phosphoglucomutase activity in erythrocytes and the inhibitor constant for lithium in a population of healthy subjects and compared them to those of bipolar patients treated with lithium or carbamazepine. The specific activity of phosphoglucomutase measured in vitro in erythrocytes from control subjects presented a normal distribution, with the difference between the lowest and the highest activity being approximately 2-fold (0.53-1.10 nmol mg Hb-1 min-1). Comparison of phosphoglucomutase activity in untreated bipolar patients and control subjects showed no significant difference, whereas comparison between bipolar patients treated with carbamazepine or lithium revealed significantly lower mean values in patients treated with carbamazepine (747.3 ± 27.6 vs 879.5 ± 35.9 pmol mg Hb-1 min-1, respectively). When we studied the concentration of lithium needed to inhibit phosphoglucomutase activity by 50%, a bimodal distribution among the population tested was obtained. The concentration of LiCl needed to inhibit phosphoglucomutase activity by 50% was 0.35 to 1.8 mM in one group of subjects and in the other it was 3 to 4 mM. These results suggest that phosphoglucomutase activity may be significant in patients with bipolar disorder treated with lithium and carbamazepine.

N-terminal-pro-brain natriuretic peptide, but not brain natriuretic peptide, is increased in patients with severe obesity

Elevated body mass index (BMI) has been reported as a risk factor for heart failure. Prevention of heart failure through identification and management of risk factors and preclinical phases of the disease is a priority. Levels of natriuretic peptides as well as activity of their receptors have been found altered in obese persons with some conflicting results. We investigated cardiac involvement in severely obese patients by determining N-terminal-pro-brain natriuretic peptide (NT-proBNP) and brain natriuretic peptide (BNP) and attempting to correlate the levels of these peptides in serum and plasma, respectively, with BMI, duration of obesity, waist circumference, and echocardiographic parameters. Thirty-three patients with severe obesity (mean BMI: 46.39 kg/m², mean age: 39 years) were studied. The control group contained 30 healthy age-matched individuals (BMI: <25 kg/m², mean age: 43 years). The t-test and Spearman correlation were used for statistical analysis. Log-NT-proBNP was significantly higher (P = 0.003) in obese patients (mean 1.67, 95% CI: 1.50-1.83 log pg/mL) compared to controls (mean: 1.32, 95% CI: 1.17-1.47 log pg/mL). The Log-NT-proBNP concentration correlated with duration of obesity (r = 0.339, P < 0.004). No difference was detected in the Log-BNP concentration (P = 0.63) of obese patients (mean: 0.73, 95% CI: 0.46-1.00 log pg/mL) compared to controls (mean: 0.66, 95% CI: 0.51-0.81 log pg/mL). NT-proBNP, but not BNP, is increased in severely obese patients and its concentration in serum is correlated with duration of obesity. NT-proBNP may be useful as an early diagnostic tool for the detection of cardiac burden due to severe obesity.

Effect of metabolic control on interferon-gamma and interleukin-10 production by peripheral blood mononuclear cells from type 1 and type 2 diabetic patients

The objective of the present study was to evaluate the production of cytokines, interferon-g (INF-g) and interleukin-10 (IL-10), in cultures of peripheral blood mononuclear cells (PBMC) from type 1 and type 2 diabetic patients and to correlate it with inadequate and adequate metabolic control. We studied 11 type 1 and 13 type 2 diabetic patients and 21 healthy individuals divided into two groups (N = 11 and 10) paired by sex and age with type 1 and type 2 diabetic patients. The PBMC cultures were stimulated with concanavalin-A to measure INF-g and IL-10 supernatant concentration by ELISA. For patients with inadequate metabolic control, the cultures were performed on the first day of hospitalization and again after intensive treatment to achieve adequate control. INF-g levels in the supernatants of type 1 diabetic patient cultures were higher compared to type 2 diabetic patients with adequate metabolic control (P < 0.001). Additionally, INF-g and IL-10 tended to increase the liberation of PBMC from type 1 and 2 diabetic patients with adequate metabolic control (P = 0.009 and 0.09, respectively). The increased levels of INF-g and IL-10 released from PBMC of type 1 and 2 diabetic patients with adequate metabolic control suggest that diabetic control improves the capacity of activation and maintenance of the immune response, reducing the susceptibility to infections.

Lipolysis of emulsion models of triglyceride-rich lipoproteins is altered in male patients with abdominal aorta aneurysm

Disorders of the lipid metabolism may play a role in the genesis of abdominal aorta aneurysm. The present study examined the intravascular catabolism of chylomicrons, the lipoproteins that carry the dietary lipids absorbed by the intestine in the circulation in patients with abdominal aorta aneurysm. Thirteen male patients (72 ± 5 years) with abdominal aorta aneurysm with normal plasma lipid profile and 13 healthy male control subjects (73 ± 5 years) participated in the study. The method of chylomicron-like emulsions was used to evaluate this metabolism. The emulsion labeled with 14C-cholesteryl oleate and ³H-triolein was injected intravenously in both groups. Blood samples were taken at regular intervals over 60 min to determine the decay curves. The fractional clearance rate (FCR) of the radioactive labels was calculated by compartmental analysis. The FCR of the emulsion with ³H-triolein was smaller in the aortic aneurysm patients than in controls (0.025 ± 0.017 vs 0.039 ± 0.019 min-1; P < 0.05), but the FCR of14C-cholesteryl oleate of both groups did not differ. In conclusion, as indicated by the triglyceride FCR, chylomicron lipolysis is diminished in male patients with aortic aneurysm, whereas the remnant removal which is traced by the cholesteryl oleate FCR is not altered. The results suggest that defects in the chylomicron metabolism may represent a risk factor for development of abdominal aortic aneurysm.