Hepatitis C virus infection, cryoglobulinemia, and peripheral neuropathy: a case report

Hepatitis C virus (HCV) is essentially hepatotropic but its manifestations can extend beyond the liver. It can be associated with autoimmune diseases, such as mixed cryoglobulinemia, membranoproliferative glomerulonephritis, autoimmune thyroiditis, and lymphoproliferative disorders. The mechanisms that trigger these manifestations are not completely understood. We describe a 48-year-old man with chronic HCV infection (circulating HCV RNA and moderate hepatitis as indicated by liver biopsy), cryoglobulinemia, and sensory and motor peripheral neuropathy. The diagnosis of multineuropathy was confirmed by clinical examination and electromyographic tests. A nerve biopsy revealed an inflammatory infiltrate in the perineurial space and signs of demyelination and axonal degeneration. The patient had no improvement of neurological symptoms with the use of analgesics and neuro-modulators. He was then treated with interferon-alpha (3 million units subcutaneously, 3 times per week) and ribavirin (500 mg orally, twice a day) for 48 weeks. Six months after the end of therapy, the patient had sustained viral response (negative HCV RNA) and remission of neurological symptoms, but cryoglobulins remained positive. A review of the literature on the pathogenesis and treatment of neurological manifestations associated with HCV infection is presented. This report underscores the need for a thorough evaluation of HCV-infected patients because of the possibility of extrahepatic manifestations. Antiviral treatment with interferon and ribavirin can be effective and should be considered in patients with neurological complications associated with HCV infection.

Frequency of CCR5delta32 in Brazilian populations

A sample of 103 randomly chosen healthy individuals from Alegrete, RS, Brazil, was tested for the CCR5delta32 allele, which is known to influence susceptibility to HIV-1 infection. The CCR5delta32 allele was identified by PCR amplification using specific primers flanking the region of deletion, followed by electrophoresis on a 3% agarose gel. The data obtained were compared to those reported for other populations and interpreted in terms of Brazilian history. The individuals studied came from a highly admixed population. Most of them were identified as white (N = 59), while blacks and browns (mulattoes) were N = 13 and N = 31, respectively. The observed frequencies, considering the white, black and brown samples (6.8, 3.8, and 6.4%, respectively), suggest an important European parental contribution, even in populations identified as black and brown. However, in Brazil as a whole, this allele shows gradients indicating a relatively good correlation with the classification based on skin color and other physical traits, used here to define major Brazilian population groups.

Peripheral markers of oxidative stress in chronic mercuric chloride intoxication

The present study was designed to evaluate the time course changes in peripheral markers of oxidative stress in a chronic HgCl2 intoxication model. Twenty male adult Wistar rats were treated subcutaneously daily for 30 days and divided into two groups of 10 animals each: Hg, which received HgCl2 (0.16 mg kg-1 day-1), and control, receiving the same volume of saline solution. Blood was collected at the first, second and fourth weeks of Hg administration to evaluate lipid peroxidation (LPO), total radical trapping antioxidant potential (TRAP), and superoxide dismutase (Cu,Zn-SOD), glutathione peroxidase (GPx), glutathione-S-transferase (GST), and catalase (CAT). HgCl2 administration induced a rise (by 26%) in LPO compared to control (143 ± 10 cps/mg hemoglobin) in the second week and no difference was found at the end of the treatment. At that time, GST and GPx were higher (14 and 24%, respectively) in the Hg group, and Cu,Zn-SOD was lower (54%) compared to control. At the end of the treatment, Cu,Zn-SOD and CAT were higher (43 and 10%, respectively) in the Hg group compared to control (4.6 ± 0.3 U/mg protein; 37 ± 0.9 pmol/mg protein, respectively). TRAP was lower (69%) in the first week compared to control (43.8 ± 1.9 mM Trolox). These data provide evidence that HgCl2 administration is accompanied by systemic oxidative damage in the initial phase of the process, which leads to adaptive changes in the antioxidant reserve, thus decreasing the oxidative injury at the end of 30 days of HgCl2 administration. These results suggest that a preventive treatment with antioxidants would help to avoid oxidative damage in subjects with chronic intoxication.

Effects of stress on catecholamine stores in central and peripheral tissues of long-term socially isolated rats

Both the peripheral sympatho-adrenomedullary and central catecholaminergic systems are activated by various psycho-social and physical stressors. Catecholamine stores in the hypothalamus, hippocampus, adrenal glands, and heart auricles of long-term socially isolated (21 days) and control 3-month-old male Wistar rats, as well as their response to immobilization of all 4 limbs and head fixed for 2 h and cold stress (4ºC, 2 h), were studied. A simultaneous single isotope radioenzymatic assay based on the conversion of catecholamines to the corresponding O-methylated derivatives by catechol-O-methyl-transferase in the presence of S-adenosyl-l-(³H-methyl)-methionine was used. The O-methylated derivatives were oxidized to ³H-vanilline and the radioactivity measured. Social isolation produced depletion of hypothalamic norepinephrine (about 18%) and hippocampal dopamine (about 20%) stores and no changes in peripheral tissues. Immobilization decreased catecholamine stores (approximately 39%) in central and peripheral tissues of control animals. However, in socially isolated rats, these reductions were observed only in the hippocampus and peripheral tissues. Cold did not affect hypothalamic catecholamine stores but reduced hippocampal dopamine (about 20%) as well as norepinephrine stores in peripheral tissues both in control and socially isolated rats, while epinephrine levels were unchanged. Thus, immobilization was more efficient in reducing catecholamine stores in control and chronically isolated rats compared to cold stress. The differences in rearing conditions appear to influence the response of adult animals to additional stress. In addition, the influence of previous exposure to a stressor on catecholaminergic activity in the brainstem depends on both the particular catecholaminergic area studied and the properties of additional acute stress. Therefore, the sensitivity of the catecholaminergic system to habituation appears to be tissue-specific.

Control of attention by a peripheral visual cue depends on whether the target is difficult to discriminate

The influence of a peripheral cue represented by a gray ring on responsivity to a subsequent target varies. When a vertical line inside a ring was a go target and a white small ring inside a ring was a no-go target, reaction time was shorter at the same location relative to a different location. However, no reaction time difference between the two locations occurred when a white cross inside the ring, instead of the white vertical line inside the ring, was the go target. We investigated whether this last finding was due to a forward masking influence of the cue, a requirement of low attention for the discrimination or a lack of attention mobilization by the cue. In Experiment 1, the intensity of the cue was reduced in an attempt to reduce forward masking. In Experiment 2, the vertical line and the cross were presented in the same block of trials so as to be dealt with a common attentional strategy. In Experiments 3 and 4, the no-go target was a 45º rotated cross inside a ring to increase the difficulty of the discrimination. No evidence was obtained that the cross was forward masked by the cue nor that it demanded less attention to be discriminated from the small ring. There was a facilitation of responsivity by the cue when the small ring was replaced by the rotated cross. The results suggest that when the discrimination to be performed is too easy the cue does not mobilize attention.

Spatial and temporal variation in fish populations and assemblages in coastal waters of the northern Baltic Proper

The distribution and traits of fish are of interest both ecologically and socio-economically. In this thesis, phenotypic and structural variation in fish populations and assemblages was studied on multiple spatial and temporal scales in shallow coastal areas in the archipelago of the northern Baltic Proper. In Lumparn basin in Åland Islands, the fish assemblage displayed significant seasonal variation in depth zone distribution. The results indicate that investigating both spatial and temporal variation in small scale is crucial for understanding patterns in fish distribution and community structure in large scale. The local population of Eurasian perch Perca fluviatilis L displayed habitat-specific morphological and dietary variation. Perch in the pelagic zone were on average deeper in their body shape than the littoral ones and fed on fish and benthic invertebrates. The results differ from previous studies conducted in freshwater habitats, where the pelagic perch typically are streamlined in body shape and zooplanktivorous. Stable isotopes of carbon and nitrogen differed between perch with different stomach contents, suggesting differentiation of individual diet preferences. In the study areas Lumparn and Ivarskärsfjärden in Åland Islands and Galtfjärden in Swedish east coast, the development in fish assemblages during the 2000’s indicated a general shift towards higher abundances of small-bodied lower-order consumers, especially cyprinids. For European pikeperch Sander lucioperca L., recent declines in adult fish abundances and high mortalities (Z = 1.06–1.16) were observed, which suggests unsustainably high fishing pressure on pikeperch. Based on the results it can be hypothesized that fishing has reduced the abundances of large predatory fish, which together with bottom-up forcing by eutrophication has allowed the lower-order consumer species to increase in abundances. This thesis contributes to the scientific understanding of aquatic ecosystems with new descriptions on morphological and dietary adaptations in perch in brackish water, and on the seasonal variation in small-scale spatial fish distribution. The results also demonstrate anthropogenic effects on coastal fish communities and underline the urgency of further reducing nutrient inputs and regulating fisheries in the Baltic Sea region.

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.

Prevalence of peripheral arterial occlusive disease in patients referred to a tertiary care hospital in Salvador, Bahia, Brazil, for coronary angiography

The presence of peripheral arterial occlusive disease increases the morbidity and mortality of patients with coronary artery disease. The objective of the present study was to calculate the prevalence of peripheral arterial occlusive disease in patients referred for coronary angiography. This prevalence study was carried out at the Hemodynamics Unit of Hospital Santa Isabel, Salvador, Brazil, from December 2004 to April 2005. After approval by the Ethics Committee of the hospital, 397 patients with angiographic signs of coronary artery disease were enrolled. Diagnosis of peripheral arterial occlusive disease was made using the ankle-brachial blood pressure index (£0.90). Statistical analyses were performed using the z test and a level of significance of a = 5%, 95%CI, the chi-square test and t-test, and multiple logistic regression analysis. The prevalence of peripheral arterial occlusive disease was 34.3% (95%CI: 29.4-38.9). Mean age was 65.7 ± 9.4 years for patients with peripheral arterial occlusive disease, and 60.3 ± 9.8 years for patients without peripheral arterial occlusive disease (P = 0.0000003). The prevalence of peripheral arterial occlusive disease was 1.57 times greater in patients with hypertension (P = 0.007) and 2.91 times greater in patients with coronary stenosis ³50% (P = 0.002). Illiterate patients and those with little education had a 44% higher chance of presenting peripheral arterial occlusive disease probably as a result of public health prevention policies of limited effectiveness. The prevalence of peripheral arterial occlusive disease in patients referred to a tertiary care hospital in Salvador, Bahia, for coronary angiography, was 34.3%.

Vascular complications of black patients with type 2 diabetes mellitus in Southern Brazil

Ethnicity has been shown to be associated with micro- and macrovascular complications of diabetes in European and North American populations. We analyzed the contribution of ethnicity to the prevalence of micro- and macrovascular complications in Brazilian subjects with type 2 diabetes attending the national public health system. Data from 1810 subjects with type 2 diabetes (1512 whites and 298 blacks) were analyzed cross-sectionally. The rates of ischemic heart disease, peripheral vascular disease, stroke, distal sensory neuropathy, and diabetic retinopathy were assessed according to self-reported ethnicity using multiple logistic regression models. Compared to whites, black subjects [odds ratio = 1.72 (95%CI = 1.14-2.6)] were more likely to have ischemic heart disease when data were adjusted for age, sex, fasting plasma glucose, HDL cholesterol, hypertension, smoking habit, and serum creatinine. Blacks were also more likely to have end-stage renal disease [3.2 (1.7-6.0)] and proliferative diabetic retinopathy [1.9 (1.1-3.2)] compared to whites when data were adjusted for age, sex, fasting plasma glucose, HDL cholesterol, hypertension, and smoking habit. The rates of peripheral vascular disease, stroke and distal sensory neuropathy did not differ between groups. The higher rates of ischemic heart disease, end-stage renal disease and proliferative diabetic retinopathy in black rather than in white Brazilians were not explained by differences in conventional risk factors. Identifying which aspects of ethnicity confer a higher risk for these complications in black patients is crucial in order to understand why such differences exist and to develop more effective strategies to reduce the onset and progression of these complications.

Antinociception synergy between the peripheral and spinal sites of the heme oxygenase-carbon monoxide pathway

We have shown that the peripheral and spinal cord heme oxygenase (HO)-carbon monoxide (CO)-soluble guanylate cyclase-cGMP pathways play an important role in antinociception in the rat experimental formalin model. Our objective was to determine if there is synergism between peripheral (paw) and spinal HO-CO pathways in nociception. Rats were handled and adapted to the experimental environment for a few days before the formalin test, in which 50 µL of a 1% formalin was injected subcutaneously into the dorsal surface of the right hind paw. The animals were then observed for 1 h and the frequency of flinching behavior was taken to represent the nociceptive response. Thirty minutes before the test, rats were pretreated with intrathecal injections of the HO inhibitor, zinc deuteroporphyrin 2,4-bis glycol (ZnDPBG) or heme-lysinate, which is a substrate of the HO pathway. The paw treatments took place 20 min before the test. Low doses of ZnDPBG did not increase nociception, while a low heme-lysinate dose did not change flinching behavior after paw or spinal injections. Combined subactive spinal (50 nmol) and peripheral (40 nmol) low doses of ZnDPBG induced hypernociception (increase of 80% in the first and 25% in the second phase flinching), whereas combined spinal-peripheral heme-lysinate (50 and 30 nmol) led to second phase antinociception (40% reduction in flinching). These findings suggest a synergy between the peripheral and spinal HO-CO pathways. Local activation of the HO system probably regulates the nociception initiation in peripheral tissue and participates in buffering the emerging nociceptive signals at the peripheral and spinal sites of action. In short, an antinociceptive synergy exists between peripheral and spinal HO pathways, which may reduce the doses required and side effects.

High prevalence of the GSTM3*A/B polymorphism in sub-Sarahan African populations

A 3-bp insertion/deletion polymorphism in intron 6 of GSTM3 (rs1799735, GSTM3*A/*B) affects the activity of the phase 2 xenobiotic metabolizing enzyme GSTM3 and has been associated with increased cancer risk. The GSTM3*B allele is rare or absent in Southeast Asians, occurs in 5-20% of Europeans but was detected in 80% of Bantu from South Africa. The wide genetic diversity among Africans led us to investigate whether the high frequency of GSTM3*B prevailed in other sub-Saharan African populations. In 168 healthy individuals from Angola, Mozambique and the São Tomé e Príncipe islands, the GSTM3*B allele was three times more frequent (0.74-0.78) than the GSTM3*A allele (0.22-0.26), with no significant differences in allele frequency across the three groups. We combined these data with previously published results to carry out a multidimensional scaling analysis, which provided a visualization of the worldwide population affinities based on the GSTM3 *A/*B polymorphism.

Effect of TNF-α production inhibitors on the production of pro-inflammatory cytokines by peripheral blood mononuclear cells from HTLV-1-infected individuals

Human T lymphotropic virus type 1 (HTLV-1) is the causal agent of myelopathy/tropical spastic paraparesis (HAM/TSP), a disease mediated by the immune response. HTLV-1 induces a spontaneous proliferation and production of pro-inflammatory cytokines by T cells, and increasing interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) levels are potentially involved in tissue damage in diseases related to HTLV-1. This exaggerated immune response is also due to an inability of the natural regulatory mechanisms to down-modulate the immune response in this group of patients. TNF-α inhibitors reduce inflammation and have been shown to improve chronic inflammatory diseases in clinical trials. The aim of this study was to evaluate the ability of pentoxifylline, forskolin, rolipram, and thalidomide to decrease in vitro production of TNF-α and IFN-γ in cells of HTLV-1-infected subjects. Participants of the study included 19 patients with HAM/TSP (mean age, 53 ± 11; male:female ratio, 1:1) and 18 HTLV-1 carriers (mean age, 47 ± 11; male:female ratio, 1:2.6). Cytokines were determined by ELISA in supernatants of mononuclear cell cultures. Pentoxifylline inhibited TNF-α and IFN-γ synthesis with the minimum dose used (50 µM). The results with forskolin were similar to those observed with pentoxifylline. The doses of rolipram used were 0.01-1 µM and the best inhibition of TNF-α production was achieved with 1 µM and for IFN-γ production it was 0.01 µM. The minimum dose of thalidomide used (1 µM) inhibited TNF-α production but thalidomide did not inhibit IFN-γ production even when the maximum dose (50 µM) was used. All drugs had an in vitro inhibitory effect on TNF-α production and, with the exception of thalidomide, all of them also decreased IFN-γ production.

Cardiovascular effects of the intracerebroventricular injection of adrenomedullin: roles of the peripheral vasopressin and central cholinergic systems

Our objective was to investigate in conscious Sprague-Dawley (6-8 weeks, 250-300 g) female rats (N = 7 in each group) the effects of intracerebroventricularly (icv) injected adrenomedullin (ADM) on blood pressure and heart rate (HR), and to determine if ADM and calcitonin gene-related peptide (CGRP) receptors, peripheral V1 receptors or the central cholinergic system play roles in these cardiovascular effects. Blood pressure and HR were observed before and for 30 min following drug injections. The following results were obtained: 1) icv ADM (750 ng/10 µL) caused an increase in both blood pressure and HR (DMAP = 11.8 ± 2.3 mmHg and ΔHR = 39.7 ± 4.8 bpm). 2) Pretreatment with a CGRP receptor antagonist (CGRP8-37) and ADM receptor antagonist (ADM22-52) blocked the effect of central ADM on blood pressure and HR. 3) The nicotinic receptor antagonist mecamylamine (25 µg/10 µL, icv) and the muscarinic receptor antagonist atropine (5 µg/10 µL, icv) prevented the stimulating effect of ADM on blood pressure. The effect of ADM on HR was blocked only by atropine (5 µg/10 µL, icv). 4) The V1 receptor antagonist [β-mercapto-β-β-cyclopentamethylenepropionyl¹, O-me-Tyr²,Arg8]-vasopressin (V2255; 10 µg/kg), that was applied intravenously, prevented the effect of ADM on blood pressure and HR. This is the first study reporting the role of specific ADM and CGRP receptors, especially the role of nicotinic and muscarinic central cholinergic receptors and the role of peripheral V1 receptors in the increasing effects of icv ADM on blood pressure and HR.

Protein turnover, amino acid requirements and recommendations for athletes and active populations

Skeletal muscle is the major deposit of protein molecules. As for any cell or tissue, total muscle protein reflects a dynamic turnover between net protein synthesis and degradation. Noninvasive and invasive techniques have been applied to determine amino acid catabolism and muscle protein building at rest, during exercise and during the recovery period after a single experiment or training sessions. Stable isotopic tracers (13C-lysine, 15N-glycine, ²H5-phenylalanine) and arteriovenous differences have been used in studies of skeletal muscle and collagen tissues under resting and exercise conditions. There are different fractional synthesis rates in skeletal muscle and tendon tissues, but there is no major difference between collagen and myofibrillar protein synthesis. Strenuous exercise provokes increased proteolysis and decreased protein synthesis, the opposite occurring during the recovery period. Individuals who exercise respond differently when resistance and endurance types of contractions are compared. Endurance exercise induces a greater oxidative capacity (enzymes) compared to resistance exercise, which induces fiber hypertrophy (myofibrils). Nitrogen balance (difference between protein intake and protein degradation) for athletes is usually balanced when the intake of protein reaches 1.2 g·kg-1·day-1 compared to 0.8 g·kg-1·day-1 in resting individuals. Muscular activities promote a cascade of signals leading to the stimulation of eukaryotic initiation of myofibrillar protein synthesis. As suggested in several publications, a bolus of 15-20 g protein (from skimmed milk or whey proteins) and carbohydrate (± 30 g maltodextrine) drinks is needed immediately after stopping exercise to stimulate muscle protein and tendon collagen turnover within 1 h.

Participation of cannabinoid receptors in peripheral nociception induced by some NSAIDs

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been used extensively to control inflammatory pain. Several peripheral antinociceptive mechanisms have been described, such as opioid system and NO/cGMP/KATP pathway activation. There is evidence that the cannabinoid system can also contribute to the in vivo pharmacological effects of ibuprofen and indomethacin. However, there is no evidence of the involvement of the endocannabinoid system in the peripheral antinociception induced by NSAIDs. Thus, the aim of this study was to investigate the participation of the endocannabinoid system in the peripheral antinociceptive effect of NSAIDs. All experiments were performed on male Wistar rats (160-200 g; N = 4 per group). Hyperalgesia was induced by a subcutaneous intraplantar (ipl) injection of prostaglandin E2 (PGE2, 2 μg/paw) in the rat’s hindpaw and measured by the paw pressure test 3 h after injection. The weight in grams required to elicit a nociceptive response, paw flexion, was determined as the nociceptive threshold. The hyperalgesia was calculated as the difference between the measurements made before and after PGE2, which induced hyperalgesia (mean = 83.3 ± 4.505 g). AM-251 (80 μg/paw) and AM-630 (100 μg/paw) were used as CB1 and CB2 cannabinoid receptor antagonists, respectively. Ipl injection of 40 μg dipyrone (mean = 5.825 ± 2.842 g), 20 μg diclofenac (mean = 4.825 ± 3.850 g) and 40 μg indomethacin (mean = 6.650 ± 3.611 g) elicited a local peripheral antinociceptive effect. This effect was not antagonized by ipl CB1 cannabinoid antagonist to dipyrone (mean = 5.00 ± 0.9815 g), diclofenac (mean = 2.50 ± 0.8337 g) and indomethacin (mean = 6.650 ± 4.069 g) or CB2 cannabinoid antagonist to dipyrone (mean = 1.050 ± 6.436 g), diclofenac (mean = 6.675 ± 1.368 g) and indomethacin (mean = 2.85 ± 5.01 g). Thus, cannabinoid receptors do not seem to be involved in the peripheral antinociceptive mechanism of the NSAIDs dipyrone, diclofenac and indomethacin.