Acute dacryocystitis: another clinical manifestation of sporotrichosis

Sporotrichosis associated with exposure to domestic cats is hyperendemic in Rio deJaneiro, Brazil. A review of the clinical records at our institute revealed fourpatients with clinical signs of dacryocystitis and a positive conjunctival culturefor Sporothrix who were diagnosed with Sporothrixdacryocystitis. Three patients were children (< 13 years of age) and one patientwas an adult. Two patients reported contact with a cat that had sporotrichosis.Dacryocystitis was associated with nodular, ulcerated lesions on the face of onepatient and with granulomatous conjunctivitis in two patients; however, thiscondition manifested as an isolated disease in another patient. All of the patientswere cured of the fungal infections, but three patients had chronic dacryocystitisand one patient developed a cutaneous fistula. Sporotrichosis is usually a benigndisease, but may cause severe complications when the eye and the adnexa are affected.Physicians, especially ophthalmologists in endemic areas, should be aware of theophthalmological manifestations and complications of sporotrichosis.     

Superoxide dismutase, catalase and glutathione peroxidase activities in the lymphoid organs and skeletal muscles of rats treated with dexamethasone

The effect of dexamethasone (a synthetic glucocorticoid) on the activity of antioxidant enzymes (superoxide dismutase (SOD), catalase and glutathione peroxidase) of the lymphoid organs (mesenteric lymph nodes (MLN), spleen and thymus) was investigated. For comparison with non-immune tissues, skeletal muscles (soleus and gastrocnemius (GC) were also studied. As an indication of the occurrence of lipid peroxidation, the content of thiobarbituric acid reactant substances (TBARs) was also determined. Dexamethasone treatment decreased the TBARs content of the lymphoid organs and raised it in the GC and soleus muscles. The activity of Cu/Zn-SOD was reduced in all tissues. However, the activity of Mn-SOD was decreased in the MLN and soleus muscle only. The activity of catalase was reduced in the MLN and thymus and raised in the spleen and GC and soleus muscles. The imposed treatment raised the activity of GPX in the MLN, thymus and spleen and reduced it in GC and soleus muscles. These data led us to postulate that the mechanism for the therapeutic effect of glucocorticoids as antiinflammatory and immunosuppressive agents might include modification of antioxidant enzyme activities.     

Diet‐induced obesity impairs AKT signalling in the retina and causes retinal degeneration

Retinopathy, a common complication of diabetes, is characterized by an unbalanced production of nitric oxide (NO), a process regulated by nitric oxide synthase (NOS). We hypothesized that retinopathy might stem from changes in the insulin receptor substrate (IRS)/PI3K/AKT pathway and/or expression of NOS isoforms. Thus, we analysed the morphology and apoptosis index in retinas of obese rats in whom insulin resistance had been induced by a high‐fat diet (HFD). Immunoblotting analysis revealed that the retinal tissue of HFD rats had lower levels of AKT₁, eNOS and nNOS protein than those of samples taken from control animals. Furthermore, immunohistochemical analyses indicated higher levels of iNOS and 4‐hydroxynonenal and a larger number of apoptotic nuclei in HFD rats. Finally, both the inner and outer retinal layers of HFD rats were thinner than those in their control counterparts. When considered alongside previous results, these patterns suggest two major ways in which HFD might impact animals: direct activity of ingested fatty acids and/or via insulin‐resistance‐induced changes in intracellular pathways. We discuss these possibilities in further detail and advocate the use of this animal model for further understanding relationships between retinopathy, metabolic syndrome and type 2 diabetes. Copyright © 2012 John Wiley & Sons, Ltd.     

Acute exercise boosts cell proliferation and the heat shock response in lymphocytes: correlation with cytokine production and extracellular-to-intracellular HSP70 ratio

Exercise stimulates immune responses, but the appropriate “doses” for such achievements are unsettled. Conversely, in metabolic tissues, exercise improves the heat shock (HS) response, a universal cytoprotective response to proteostasis challenges that are centred on the expression of the 70-kDa family of intracellular heat shock proteins (iHSP70), which are anti-inflammatory. Concurrently, exercise triggers the export of HSP70 towards the extracellular milieu (eHSP70), where they work as pro-inflammatory cytokines. As the HS response is severely compromised in chronic degenerative diseases of inflammatory nature, we wondered whether acute exercise bouts of different intensities could alter the HS response of lymphocytes from secondary lymphoid organs and whether this would be related to immunoinflammatory responses. Adult male Wistar rats swam for 20 min at low, moderate, high or strenuous intensities as per an overload in tail base. Controls remained at rest under the same conditions. Afterwards, mesenteric lymph node lymphocytes were assessed for the potency of the HS response (42 °C for 2 h), NF-κB binding activity, mitogen-stimulated proliferation and cytokine production. Exercise stimulated cell proliferation in an “inverted-U” fashion peaking at moderate load, which was paralleled by suppression of NF-κB activation and nuclear location, and followed by enhanced HS response in relation to non-exercised animals. Comparative levels of eHSP70 to iHSP70 (H-index) matched IL-2/IL-10 ratios. We conclude that exercise, in a workload-dependent way, stimulates immunoinflammatory performance of lymphocytes of tissues far from the circulation and this is associated with H-index of stress response, which is useful to assess training status and immunosurveillance balance.     

Fish oil supplementation for two generations increases insulin sensitivity in rats

We investigated the effect of fish oil supplementation for two consecutive generations on insulin sensitivity in rats. After the nursing period (21 days), female rats from the same prole were divided into two groups: (a) control group and (b) fish oil group. Female rats were supplemented with water (control) or fish oil at 1 g/kg body weight as a single bolus for 3 months. After this period, female rats were mated with male Wistar rats fed on a balanced chow diet (not supplemented). Female rats continued to receive supplementation throughout gestation and lactation periods. The same treatment was performed for the next two generations (G1 and G2). At 75 days of age, male offspring from G1 and G2 generations from both groups were used in the experiments. G1 rats did not present any difference with control rats. However, G2 rats presented reduction in glycemia and lipidemia and improvement in in vivo insulin sensitivity (model assessment of insulin resistance, insulin tolerance test) as well as in vitro insulin sensitivity in soleus muscle (glucose uptake and metabolism). This effect was associated with increased insulin-stimulated p38 MAP kinase phosphorylation and lower n-6/n-3 fatty acid ratio, but not with activation of proteins from insulin signaling (IR, IRS-1 and Akt). Global DNA methylation was decreased in liver but not in soleus muscle. These results suggest that long-term fish oil supplementation improves insulin sensitivity in association with increased insulin-stimulated p38 activation and decreased n-6:n-3 ratio in skeletal muscle and decreased global DNA methylation in liver.     

Glucose and glutamine utilization by rat lymphocytes, monocytes and neutrophils in culture: a comparative study

Glucose and glutamine utilization and production of glutamate and lactate were determined for up to 48 h in lymphocytes, monocytes and neutrophils cultured in medium rich in metabolites and vitamins. Glucose was utilized by the three cell types in culture in the following order: neutrophils > monocytes > lymphocytes, whereas lactate was produced in the order: monocytes > neutrophils > lymphocytes. The consumption of glucose followed the activity of glucose-6-phosphate dehydrogenase but it was not related to hexokinase activity. Glutamine was consumed by the three leukocyte types in culture as follows: neutrophils > lymphocytes > or = monocytes. The consumption of glutamine was not fully related to the activity of phosphate-dependent glutaminase. The production of glutamate was not remarkably different among the three cell types. For comparison, glutamine and glucose utilization and glutamate and lactate production were also evaluated using 1-h incubated leukocytes. Under this condition, only glucose or glutamine was added to the medium. Glucose was utilized as follows: neutrophils > monocytes > lymphocytes, whereas lactate was produced in the following order: monocytes > or = neutrophils > lymphocytes. Glutamine was consumed as follows: neutrophils > lymphocytes > monocytes, whereas glutamate was produced as follows: neutrophils > or = monocytes = lymphocytes. The ratio of the amount of glucose/glutamine consumed by 1-h incubated cells was 0.5 for neutrophils, 1.5 for monocytes, and 0.3 for lymphocytes. However, the three cell types cultured for 48 h utilized glucose to a much higher degree than glutamine. The ratio of the amount of glucose/glutamine utilized by the cultured cells was 8.9 for neutrophils, 16.4 for monocytes, and 6.7 for lymphocytes. These observations support the proposition that glutamine is required in much higher amounts than glucose to accomplish the total metabolic requirement of leukocytes. Under conditions closer to physiological when the availability of a variety of metabolites and vitamins is not restricted, glucose is the preferred substrate for lymphocytes, monocytes and neutrophils.     

Heavy Metals in Hair of Wild Canids from the Brazilian Cerrado

In this study, we aimed to assess whether free-ranging wild canids are exposed to heavy metals in one of the most developed and populated regions of Brazil. Hair of 26 wild canids (maned wolves Chrysocyon brachyurus, crab-eating foxes Cerdocyon thous, and hoary foxes Lycalopex vetulus) from the Cerrado biome in Southeast Brazil were analyzed by spectrophotometry to detect cadmium, chromium, and lead, and also the essential copper, iron, manganese, and zinc traces. All samples showed traces of copper, iron, manganese, and zinc. Non-essential lead was detected in 57% (2.35 ± 0.99 mg/kg), and chromium in 88% (2.98 ± 1.56 mg/kg) of samples. Cadmium traces (detection limit 0.8 mg/kg) were not found. Crab-eating foxes had more copper, iron, and manganese in hair than maned wolves. Correlations among element levels differed between maned wolves and crab-eating foxes. Concentrations of chromium and lead were outstandingly higher than in wild canids from other areas. Addressing the causes of such levels and the impacts of the heavy metal pollution in Neotropical ecosystems is urgent for animal health and conservation purposes. We argue that heavy metal pollution should be considered as dangerous threats to wildlife health in Brazil and recommend hair sampling as a biomonitoring tool for heavy metals in Neotropical terrestrial mammals.     

Time-dependent effects of fatty acids on skeletal muscle metabolism

Increased plasma levels of free fatty acids (FFA) occur in states of insulin resistance such as type 2 diabetes mellitus, obesity, and metabolic syndrome. These high levels of plasma FFA seem to play an important role for the development of insulin resistance but the mechanisms involved are not known. We demonstrated that acute exposure to FFA (1 h) in rat incubated skeletal muscle leads to an increase in the insulin-stimulated glycogen synthesis and glucose oxidation. In conditions of prolonged exposure to FFA, however, the insulin-stimulated glucose uptake and metabolism is impaired in skeletal muscle. In this review, we discuss the differences between the effects of acute and prolonged exposure to FFA on skeletal muscle glucose metabolism and the possible mechanisms involved in the FFA-induced insulin resistance.