Bullet embolism of pulmonary artery: a case report

The authors report the case of a patient victim of gunshots, with a very rare complication: venous bullet embolism from the left external iliac vein to the lingular segment of the left pulmonary artery. Diagnosis is made with whole-body radiography or computed tomography. Digital angiography is reserved for supplementary diagnosis or to be used as a therapeutic procedure.

Paradoxical increase of exploratory behavior in the elevated plus-maze by rats exposed to two kinds of aversive stimuli

Albino rats were submitted to a 24-h period of social isolation (individual housing) combined with 0, 1, 2 or 3 twenty-four-hour periods of exposure to different vivaria (novelty) and tested in the elevated plus-maze. Results, reported as mean ± SEM for N = 12, show that the time (in seconds) spent in the open arms by rats exposed to novelty for 0, 1, 2 and 3 days was 28.3 ± 4.4, 31.6 ± 3.2, 29.1 ± 3.5 and 25.0 ± 3.3, respectively, when grouped in the same vivarium; 29.6 ± 2.7, 7.6 ± 2.1, 9.6 ± 4.4 and 28.5 ± 3.7 when grouped in different vivaria; 2.9 ± 1.1, 1.8 ± 1.0, 2.7 ± 1.1 and 0 ± 0 when isolated in the same vivarium, and 2.6 ± 1.1, 31.5 ± 8.2, 24.8 ± 4.2 and 0 ± 0 when isolated in different vivaria. The number of entries into the open and closed arms followed a similar trend. This indicates that, separately, both exposure to novelty and isolation are aversive manipulations. Paradoxically, when novelty was combined with a concomitant 24-h period of social isolation prior to testing, the decrease in exploratory behavior caused by either of the two aversive manipulations alone was reverted. These results are indicative that less intense anxiety triggers mechanisms mediating less energetic behavior such as freezing, while higher levels trigger mechanisms mediating more vigorous action, such as flight/fight behavior, since the combination of two aversive situations resulted in more exploratory behavior than with either alone. They are also suggestive of habituation to the effects of novelty, since exposure to it for 3 days produced exploratory behavior similar to that of controls

Paradoxical sleep deprivation increases plasma endothelin levels

The endothelins (ET-1, 2 and 3) constitute a family of 21 amino acid peptides with potent biological activities. ET-1 is one of the most potent endogenous vasoconstrictors so far identified and its increased concentration in plasma appears to be closely related to the pathogenesis of arterial hypertension as well as to obstructive sleep apnea (OSA). OSA patients exhibit repetitive episodes of apnea and hypopnea that result in hypoxia and consecutive arousals. These patients are chronically sleep deprived, which may aggravate the hypertensive features, since literature data show that sleep deprivation results in hypertension both in humans and in animals. Based on the reported relationship between ET-1, hypertension and sleep deprivation consequences, the purpose of the present study was to determine plasma ET concentrations in paradoxical sleep-deprived animals. Male Wistar rats, 3 to 4 months old (N = 10 per group), were deprived of sleep for 24 and 96 h by the platform technique and plasma ET-1/2 was measured by radioimmunoassay. Analysis of plasma revealed that 96 h of sleep deprivation induced a significant increase in ET-1/2 release (6.58 fmol/ml) compared to control (5.07 fmol/ml). These data show that sleep deprivation altered plasma ET-1/2 concentrations, suggesting that such an increase may participate in the genesis of arterial hypertension and cardiorespiratory changes observed after sleep deprivation.

Mechanisms underlying gas exchange alterations in an experimental model of pulmonary embolism

The aim of the present study was to determine the ventilation/perfusion ratio that contributes to hypoxemia in pulmonary embolism by analyzing blood gases and volumetric capnography in a model of experimental acute pulmonary embolism. Pulmonary embolization with autologous blood clots was induced in seven pigs weighing 24.00 ± 0.6 kg, anesthetized and mechanically ventilated. Significant changes occurred from baseline to 20 min after embolization, such as reduction in oxygen partial pressures in arterial blood (from 87.71 ± 8.64 to 39.14 ± 6.77 mmHg) and alveolar air (from 92.97 ± 2.14 to 63.91 ± 8.27 mmHg). The effective alveolar ventilation exhibited a significant reduction (from 199.62 ± 42.01 to 84.34 ± 44.13) consistent with the fall in alveolar gas volume that effectively participated in gas exchange. The relation between the alveolar ventilation that effectively participated in gas exchange and cardiac output (V Aeff/Q ratio) also presented a significant reduction after embolization (from 0.96 ± 0.34 to 0.33 ± 0.17 fraction). The carbon dioxide partial pressure increased significantly in arterial blood (from 37.51 ± 1.71 to 60.76 ± 6.62 mmHg), but decreased significantly in exhaled air at the end of the respiratory cycle (from 35.57 ± 1.22 to 23.15 ± 8.24 mmHg). Exhaled air at the end of the respiratory cycle returned to baseline values 40 min after embolism. The arterial to alveolar carbon dioxide gradient increased significantly (from 1.94 ± 1.36 to 37.61 ± 12.79 mmHg), as also did the calculated alveolar (from 56.38 ± 22.47 to 178.09 ± 37.46 mL) and physiological (from 0.37 ± 0.05 to 0.75 ± 0.10 fraction) dead spaces. Based on our data, we conclude that the severe arterial hypoxemia observed in this experimental model may be attributed to the reduction of the V Aeff/Q ratio. We were also able to demonstrate that V Aeff/Q progressively improves after embolization, a fact attributed to the alveolar ventilation redistribution induced by hypocapnic bronchoconstriction.

Effect of sildenafil (Viagra®) on the genital reflexes of paradoxical sleep-deprived male rats

Since there is evidence that paradoxical sleep deprivation (PSD) elicits penile erection (PE) and ejaculation (EJ), and that the erectile response of rats is mediated by nitric oxide, the present study sought to extend the latter finding by assessing the effects of sildenafil on the genital reflexes of male Wistar rats subjected to PSD. We also determined the influence of sildenafil on hormone concentrations. In the first experiment, sildenafil at doses ranging from 0.08 to 0.32 mg/kg was administered intraperitoneally to rats that had been deprived of sleep for 4 days and to home cage controls (N = 8-10/group). The frequency of PE and EJ was measured for 60 min. PSD alone induced PE in 50% of the animals; however, a single injection of sildenafil did not significantly increase the percentage of rats displaying PE compared to PSD-saline or to home cage groups. PSD alone also induced spontaneous EJ, but this response was not potentiated by sildenafil in the dose range tested. Testosterone concentrations were significantly lower in PSD rats (137 ± 22 ng/dL) than in controls (365 ± 38 ng/dL), whereas progesterone (0.9 ± 0.1 vs 5.4 ± 1 ng/mL) and plasma dopamine (103.4 ± 30 vs 262.6 ± 77 pg/mL) increased. These changes did not occur after sildenafil treatment. The data show that although sildenafil did not alter the frequency of genital reflexes, it antagonized hormonal (testosterone and progesterone) and plasma dopamine changes induced by PSD. The stimulation of the genital reflexes by sildenafil did not result in potentiating effects in PSD rats.

Effects of cocaine, methamphetamine and modafinil challenge on sleep rebound after paradoxical sleep deprivation in rats

Sleep loss is both common and critically relevant to our society and might lead to the abuse of psychostimulants such as amphetamines, cocaine and modafinil. Since psychoactive substance abuse often occurs within a scenario of sleep deficit, the purpose of this investigation was to compare the sleep patterns of rats challenged with cocaine (7 mg/kg, ip), methamphetamine (7 mg/kg, ip), or modafinil (100 mg/kg, ip) subsequent to paradoxical sleep deprivation (PSD) for 96 h. Our results show that, immediately after 96 h of PSD, rats (10 per group) that were injected with a psychostimulant presented lower percentages of paradoxical sleep compared to those injected with saline (P < 0.01). Regarding slow wave sleep (SWS), rats injected with psychostimulants after PSD presented a late rebound (on the second night subsequent to the injection) in the percentage of this phase of sleep when compared to PSD rats injected with saline (P < 0.05). In addition, the current study has produced evidence of the characteristic effect of each drug on sleep architecture. Home cage control rats injected with modafinil and methamphetamine showed a reduction in SWS compared with the saline group. Methamphetamine affected sleep patterns most, since it significantly reduced paradoxical sleep, SWS and sleep efficiency before and after PSD compared to control (P < 0.05). Cocaine was the psychostimulant causing the least changes in sleep pattern in relation to those observed after saline injection. Therefore, our results suggest that abuse of these psychostimulants in a PSD paradigm aggravates their impact on sleep patterns.

Participation of the cholinergic system in the ethanol-induced suppression of paradoxical sleep in rats

Sleep disturbance is among the many consequences of ethanol abuse in both humans and rodents. Ethanol consumption can reduce REM or paradoxical sleep (PS) in humans and rats, respectively. The first aim of this study was to develop an animal model of ethanol-induced PS suppression. This model administered intragastrically (by gavage) to male Wistar rats (3 months old, 200-250 g) 0.5 to 3.5 g/kg ethanol. The 3.5 g/kg dose of ethanol suppressed the PS stage compared with the vehicle group (distilled water) during the first 2-h interval (0-2 h; 1.3 vs 10.2; P < 0.001). The second aim of this study was to investigate the mechanisms by which ethanol suppresses PS. We examined the effects of cholinergic drug pretreatment. The cholinergic system was chosen because of the involvement of cholinergic neurotransmitters in regulating the sleep-wake cycle. A second set of animals was pretreated with 2.5, 5.0, and 10 mg/kg pilocarpine (cholinergic agonist) or atropine (cholinergic antagonist). These drugs were administered 1 h prior to ethanol (3.5 g/kg) or vehicle. Treatment with atropine prior to vehicle or ethanol produced a statistically significant decrease in PS, whereas pilocarpine had no effect on minutes of PS. Although the mechanism by which ethanol induces PS suppression is not fully understood, these data suggest that the cholinergic system is not the only system involved in this interaction.

Paradoxical effect of a pequi oil-rich diet on the development of atherosclerosis: balance between antioxidant and hyperlipidemic properties

Pequi is the fruit of Caryocar brasiliense and its oil has a high concentration of monounsaturated and saturated fatty acids, which are anti- and pro-atherogenic agents, respectively, and of carotenoids, which give it antioxidant properties. Our objective was to study the effect of the intake of a cholesterol-rich diet supplemented with pequi oil, compared to the same diet containing soybean oil, on atherosclerosis development, and oxidative stress in atherosclerosis-susceptible LDL receptor-deficient mice (LDLr-/-, C57BL/6-background). Female mice were fed a cholesterol-rich diet containing 7% soybean oil (Soybean group, N = 12) or 7% pequi oil (Pequi group, N = 12) for 6 weeks. The Pequi group presented a more atherogenic lipid profile and more advanced atherosclerotic lesions in the aortic root compared to the Soybean group. However, the Pequi group presented a less advanced lesion in the aorta than the Soybean group and showed lower lipid peroxidation (Soybean group: 50.2 ± 7.1; Pequi group: 30.0 ± 4.8 µmol MDA/mg protein) and anti-oxidized LDL autoantibodies (Soybean group: 35.7 ± 9.4; Pequi group: 15.6 ± 3.7 arbitrary units). Peritoneal macrophages from the Pequi group stimulated with zymosan showed a reduction in the release of reactive oxygen species compared to the Soybean group. Our data suggest that a pequi oil-rich diet slows atherogenesis in the initial stages, possibly due to its antioxidant activity. However, the increase of serum cholesterol induces a more prominent LDL migration toward the intimae of arteries, increasing the advanced atherosclerotic plaque. In conclusion, pequi oil associated with an atherogenic diet worsens the lipid profile and accelerates the formation of advanced atherosclerotic lesions despite its antioxidant action.

EFFECTS OF VITAMIN C SUPPLEMENTATION ON THE CHRONIC PHASE OF CHAGAS DISEASE

Introduction:In order to examine the effectiveness of vitamin C (ascorbic acid) in combating the oxidative insult caused by Trypanosoma cruzi during the development of the chronic phase of Chagas disease, Swiss mice were infected intraperitoneally with 5.0 × 104 trypomastigotes of T. cruzi QM1strain.Methods:Mice were given supplements of two different doses of vitamin C for 180 days. Levels of lipid oxidation (as indicated by thiobarbituric acid reactive substances-TBARS), total peroxide, vitamin C, and reduced glutathione were measured in the plasma, TBARS, total peroxide and vitamin C were measured in the myocardium and histopathologic analysis was undertaken in heart, colon and skeletal muscle.Results:Animals that received a dose equivalent to 500 mg of vitamin C daily showed increased production of ROS in plasma and myocardium and a greater degree of inflammation and necrosis in skeletal muscles than those that received a lower dose or no vitamin C whatsoever.Conclusion:Although some research has shown the antioxidant effect of vitamin C, the results showed that animals subject to a 500 mg dose of vitamin C showed greater tissue damage in the chronic phase of Chagas disease, probably due to the paradoxical actions of the substance, which in this pathology, will have acted as a pro-oxidant or pro-inflammatory.

PARACOCCIDIOIDOMYCOSIS TREATMENT

SUMMARYConsidered to be an emerging endemic mycosis in Latin America, paracoccidioidomycosis is characterized by a chronic course and involvement of multiple organs in immunocompromised hosts. Infection sequelae are mainly related to pulmonary and adrenal insufficiency. The host-parasite interaction results in different expressions of the immune response depending on parasite pathogenicity, fungal load and genetic characteristics of the host. A few controlled and case series reports have shown that azoles and fast-acting sulfa derivatives are useful treatment alternatives in milder forms of the disease. For moderate/severe cases, more prolonged treatments or even parenteral routes are required especially when there is involvement of the digestive tract mucosa, resulting in poor drug absorption. Although comparative studies have reported that shorter treatment regimens with itraconazole are able to induce cure in chronically-infected patients, there are still treatment challenges such as the need for more controlled studies involving acute cases, the search for new drugs and combinations, and the search for compounds capable of modulating the immune response in severe cases as well as the paradoxical reactions.

Fatal pulmonary thromboembolism in gastrectomy intraoperative procedures by gastric adenocarcinoma: case report

The case of a patient with gastric adenocarcinoma with indication for gastrectomy is reported. The surgery took place without complications. A palliative, subtotal gastrectomy was performed after para-aortic lymph nodes compromised by neoplasm were found, which was confirmed by pathological exam of frozen sections carried out during the intervention. At the end of the gastroenteroanastomosis procedure, the patient began to show intense bradycardia: 38 beats per minute (bpm), arterial hypotension, changes in the electrocardiogram's waveform (upper unlevelling of segment ST), and cardiac arrest. Resuscitation maneuvers were performed with temporary success. Subsequently, the patient had another circulatory breakdown and again was recovered. Finally, the third cardiac arrest proved to be irreversible, and the intra-operative death occurred. Necropsy showed massive pulmonary embolism. The medical literature has recommended heparinization of patients, in an attempt to avoid pulmonary thromboembolism following major surgical interventions. However, in the present case, heparinization would have been insufficient to prevent death. This case indicates that it is necessary to develop preoperative propedeutics for diagnosing the presence of venous thrombi with potential to migrate, causing pulmonary thromboembolism (PTE). If such thrombi could be detected, preventative measures, such as filter installation in the Cava vein could be undertaken.

Unusual abdominal tumors with intracardiac extension. Two cases with successful surgical resection

Abdominal tumors that can grow through vascular lumen and spread to the right heart are rare. Although these tumors have different histologic aspects, they may cause similar abdominal and cardiac symptoms and are a serious risk factor for pulmonary embolism and sudden death when they reach the right atrium and tricuspid valve. The best treatment is radical surgical resection of the entire tumor using cardiopulmonary bypass with or without deep hypothermia and total circulatory arrest. We report the cases of two patients, the first with leiomyosarcoma of the inferior vena cava and the other with intravenous leiomyomatosis of the uterus that showed intravascular growth up to right atrium and ventricle, who underwent successful radical resection in a one-stage procedure with the use of cardiopulmonary bypass. We discuss the clinical and histologic aspects and imaging diagnosis and review the literature.

Widespread hematogenous metastases and Trousseau's syndrome in gastric adenocarcinoma

A case of widespread hematogenous metastases and Trousseau's syndrome is reported in a 40 year-old white housewife with gastric cancer, presenting subdural hematoma, ecchymoses, epistaxis, stomach and uterine bleeding. After undergoing hematoma drainage, she was unsuccessfully treated with platelets, red blood cells, plasma cryoprecipitate transfusions, and antibiotics. Necropsy disclosed gastric ring-signet adenocarcinoma invading the serous layer, with massive disseminated intravascular coagulation and systemic neoplastic embolism. Multiple old and recent hyaline (rich in fibrin and platelets) microthrombi, and tumor emboli were observed in the bone marrow, meninges, liver, lungs, kidneys, lymph nodes, adrenals, thyroid, heart, pancreas, and ovaries (Krukenberg tumor).

Atrial infarction is a unique and often unrecognized clinical entity

A patient with heart failure and acute atrial fibrillation received the final diagnosis of atrial infarction associated with ventricular infarction based on clinical findings of ischemia in association with atrial fibrillation and heart failure (mechanisms probably involved: contractile dysfunction and loss of atrial contribution). Although a transesophageal echocardiography, which could refine the diagnosis of anatomic abnormalities, was not performed, all evidence led to the diagnosis of atrial involvement. Electrocardiographic findings were consistent with Liu's major criterion 3. Therapy with digitalis, quinidine and angiotensin-converting enzyme inhibitors was chosen, as the patient had acute pulmonary edema. The use of beta-blockers and verapamil was restricted. No other complications, such as thrombo-embolism or atrial rupture, were noted.