Identification of rounded atelectasis in workers exposed to asbestos by contrast helical computed tomography

Rounded atelectasis (RA) is a benign and unusual form of subpleural lung collapse that has been described mostly in asbestos-exposed workers. This form of atelectasis manifests as a lung nodule and can be confused with bronchogenic carcinoma upon conventional radiologic examination. The objective of the present study was to evaluate the variation in contrast uptake in computed tomography for the identification of asbestos-related RA in Brazil. Between January 1998 and December 2000, high-resolution computed tomography (HRCT) was performed in 1658 asbestos-exposed workers. The diagnosis was made in nine patients based on a history of prior asbestos exposure, the presence of characteristic (HRCT) findings and lesions unchanged in size over 2 years or more. In three of them the diagnosis was confirmed during surgery. The dynamic contrast enhancement study was modified to evaluate nodules and pulmonary masses. All nine patients with RA received iodide contrast according to weight. The average enhancement after iodide contrast was infused, reported as Hounsfield units (HU), increased from 62.5 ± 9.7 to 125.4 ± 20.7 (P < 0.05), with a mean enhancement of 62.5 ± 19.7 (range 40 to 89) and with a uniform dense opacification. In conclusion, in this study all patients with RA showed contrast enhancement with uniform dense opacification. The main clinical implication of this finding is that this procedure does not permit differentiation between RA and malignant pulmonary neoplasm.

The opossum Didelphis virginiana as a synanthropic reservoir of Trypanosoma cruzi in Dzidzilché, Yucatán, México

In México, the role of mammals in the transmission cycle of Trypanosoma cruzi is poorly known. In the State of Yucatán, an endemic area of Chagas disease, both Didelphis virginiana and D. marsupialis occur sympatrically. However, until now, only the former species had been found infected with T. cruzi. To evaluate the role of D. virginiana in a peridomestic transmission, nine periods of capture-recapture were performed around the village of Dzidzilché, Yucatán. The sex, age, reproductive status, location, and presence of infection with T. cruzi were recorded for each opossum. The chromosome morphology was used to identify the opossum species. T. cruzi was identified by the presence of pseudocysts of amastigotes in cardiac muscle fibers of Balb/c mice inoculated with strains isolated from opossums. However, xenodiagnosis was the best diagnostic method. Triatoma dimidiata, the vector, were collected in and around the opossums' nests, and human dwellings; and were checked for T. cruzi. From 102 blood samples of D. virginiana examined 55 (53.9%) were positive to T. cruzi, the only two D. marsupialis captured were negative. Significant differences were found between infection, and both sex and reproductive condition. Eight out of 14 triatomines collected in peridomestic nests (57.1%), and 32 of 197 captured inside houses (16.3%) were found infected, suggesting a peridomestic transmission. The statistically high abundance of infected opossums and triatomines during the dry season (March to May) suggested the existence of a seasonality in the peridomestic transmission of T. cruzi in Dzidzilché.

Skin morphology of the mutant hairless USP mouse

The morphology of the skin of the mutant hairless USP mouse was studied by histological, histochemical and immunohistochemical methods and compared to the skin of BALB/c mice. Representative sections of the dorsal skin from mice of both strains aged 18 days, and 1, 3, 6, and 8 months were studied. Sections stained with hematoxylin and eosin showed cystic formations called utricles and dermal cysts in the dermis that increased in size and number during growth. Skin thickness increased significantly at 8 months. Sections stained with picrosirius and examined with polarized light, displayed different colors, suggesting different thicknesses of dermal collagen fibers (probably types I and III). Weigert, Verhoeff and resorcin-fuchsin stains revealed fibers of the elastic system. The PAS and Alcian blue methods revealed neutral and acid glycosaminoglycans in the skin ground substance of both mouse strains. Immunohistochemical staining for fibronectin and laminin did not show differences between the mutant and BALB/c mice. Mast cells stained by the Gomori method and macrophages positive for HAM 56 antibodies were observed in both mouse strains. Except for the presence of enlarged cysts in the hairless strain, no qualitative differences were found during development of the skin of BALB/c and the mutant hairless mice.

Effects of chronic heart disease on skeletal muscle fiber size

Size changes in muscle fibers of subjects with chronic heart disease (CHD) have been reported, although a consensus has not been achieved. The aims of the present study were to investigate a possible association between CHD and fiber size changes in the brachial biceps compared to subjects without heart disease. Forty-six muscle samples were obtained in autopsies of individuals (13 to 84 years) without neuromuscular disorders, 19 (10 males and 9 females) with, and 27 (14 males and 13 females) without CHD. In all cases muscle sections were stained with hematoxylin and eosin and processed for the visualization of myofibrillar ATPase activity. The lesser diameter of type 1 and type 2 fibers was obtained tracing their outlines (at least 150 fibers of each type per sample) onto an image analyzer connected to a computer. The results were analyzed statistically comparing males and females with and without CHD. Type 1 fiber mean lesser diameters were 51.51 and 54.52 µm in males (normal range 34-71 µm) and 45.65 and 55.42 µm in females (normal range 34-65 µm) without and with CHD, respectively; type 2 fibers measured 54.31, 58.23, 41.15, and 49.57 µm, respectively (normal range 36-79 µm for males and 32-59 µm for females). No significant difference in fiber size was detected in 24 males with and without CHD, while in 22 females there was a significant increase in size in those with cardiomyopathy. We concluded that CHD does not determine significant changes in fiber size. However, in females, there is some hypertrophy which, despite within normal range, may reflect morphologic heterogeneity of the sample, or the daily life activities in the upper limbs as a compensatory mechanism to fatigability that affect predominantly the lower limbs in subjects with CHD.

Functional mapping of the cardiorespiratory effects of dorsal and median raphe nuclei in the rat

The dorsal (DRN) and median (MRN) raphe nuclei are important sources of serotonergic innervation to the forebrain, projecting to sites involved in cardiovascular regulation. These nuclei have been mapped using electrical stimulation, which has the limitation of stimulating fibers of passage. The present study maps these areas with chemical stimulation, investigating their influence on cardiorespiratory parameters. Urethane-anesthetized (1.2 g/kg, iv) male Wistar rats (280-300 g) were instrumented for pulsatile and mean blood pressure (MBP), heart rate, renal nerve activity, and respiratory frequency recordings. Microinjections of L-glutamate (0.18 M, 50-100 nl with 1% Pontamine Sky Blue) were performed within the DRN or the MRN with glass micropipettes. At the end of the experiments the sites of microinjection were identified. The majority of sites within the MRN (86.1%) and DRN (85.4%) evoked pressor responses when stimulated (DRN: deltaMBP = +14.7 ± 1.2; MRN: deltaMBP = +13.6 ± 1.3 mmHg). The changes in renal nerve activity and respiratory rate caused by L-glutamate were +45 ± 11 and +42 ± 9% (DRN; P < 0.05%), +40 ± 10 and +29 ± 7% (MRN, P < 0.05), respectively. No significant changes were observed in saline-microinjected animals. This study shows that: a) the blood pressure increases previously observed by electrical stimulation within the raphe are due to activation of local neurons, b) this pressor effect is due to sympathoexcitation because the stimulation increased renal sympathetic activity but did not produce tachycardia, and c) the stimulation of cell bodies in these nuclei also increases the respiratory rate.

Effect of gallium-arsenide laser, gallium-aluminum-arsenide laser and healing ointment on cutaneous wound healing in Wistar rats

This study determined the effects of gallium-aluminum-arsenide laser (GaAlAs), gallium-arsenide laser (GaAs) and Dersani® healing ointment on skin wounds in Wistar rats. The parameters analyzed were: type I and III collagen fiber concentrations as well as the rate of wound closure. Five wounds, 12 mm in diameter, were made on the animals’ backs. The depth of the surgical incision was controlled by removing the epithelial tissue until the dorsal muscular fascia was exposed. The animals were anesthetized with ketamine and xylazine via intraperitoneal injection. The rats were randomly divided into five groups of 6 animals each, according to the treatment received. Group 1 (L4): GaAs laser (4 J/cm²); group 2 (L30): GaAlAs laser (30 J/cm²); group 3 (L60): GaAlAs laser (60 J/cm²); group 4 (D): Dersani® ointment; group 5 (control): 0.9% saline. The applications were made daily over a period of 20 days. Tissue fragments were stained with picrosirius to distinguish type I collagen from type III collagen. The collagen fibers were photo-documented and analyzed using the Quantum software based on the primary color spectrum (red, yellow and blue). Significant results for wound closing rate were obtained for group 1 (L4), 7.37 mm/day. The highest concentration of type III collagen fibers was observed in group 2 (L30; 37.80 ± 7.10%), which differed from control (29.86 ± 5.15%) on the 20th day of treatment. The type I collagen fibers of group 1 (L4; 2.67 ± 2.23%) and group 2 (L30; 2.87 ± 2.40%) differed significantly from control (1.77 ± 2.97%) on the 20th day of the experiment.

Alterations in psychosocial health of people affected by asbestos poisoning

OBJECTIVE To analyze the state of psychosocial and mental health of professionals affected by asbestos.METHODS A cross-sectional study was conducted with 110 professionals working in the Ferrolterra region of Spain, who were affected by asbestos poisoning. This group was compared with a group of 70 shipyard workers with no manifestation of work-related diseases. All the participants were male with a mean age of 67 years. This study was conducted in 2013, between January and June, and used the SCL-90 questionnaire by Derogatis as its primary measure for research. This questionnaire consists of 9 variables that measure psychosomatic symptoms. In addition, an overall index of psychosomatic gravity was calculated. The participants were also asked two questions concerning their overall perception of feeling good. Data were analyzed by ANOVA and logistic regression.RESULTS Participants affected by asbestos poisoning showed high occurrence rates of psychological health variables such as somatization, obsessive-compulsive, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid ideation, psychoticism, and global severity index.CONCLUSIONS Social interaction as a differentiating factor between workers affected by work-related chronic syndromes as compared to healthy participants will possibly aid in the development of intervention programs by improving the social network of affected individuals.

Quantitative analysis of collagen and elastic fibers in the transversalis fascia in direct and indirect inguinal hernia

PURPOSE: Our previous studies demonstrated structural and quantitative age-related changes of the elastic fibers in transversalis fascia, which may play a role in inguinal hernia formation. To verify whether there were differences in the extracellular matrix between direct and indirect inguinal hernia, we studied the amount of collagen and elastic fibers in the transversalis fascia of 36 male patients with indirect inguinal hernia and 21 with direct inguinal hernia. MATERIAL AND METHODS: Transversalis fascia fragments were obtained during surgical intervention and underwent histological quantitative analysis of collagen by colorimetry and analysis of elastic fibers by histomorphometry. RESULTS: We demonstrated significantly lower amounts of collagen and higher amounts of elastic fibers in transversalis fascia from patients with direct inguinal hernia compared to indirect inguinal hernia patients. The transversalis fascia from direct inguinal hernia patients showed structural changes of the mature and elaunin elastic fibers, which are responsible for elasticity, and lower density of oxytalan elastic fibers, which are responsible for resistance. These changes promoted loss of resiliency of the transversalis fascia. CONCLUSION: These results improve our understanding of the participation of the extracellular matrix in the genesis of direct inguinal hernia, suggesting a relationship with genetic defects of the elastic fiber and collagen synthesis.

Catheter ablation of atriofascicular Mahaim fibers guided by the activation potential

OBJECTIVE: To determine whether recording of the activation potential may be used as an isolated criterion to guide catheter ablation of atriofascicular Mahaim fibers. METHODS: We studied 6 patients (5 females, mean age of 26±7.3 years) with paroxysmal tachycardias with a wide QRS complex, whose electrophysiological study diagnosed atriofascicular Mahaim fibers. Mapping and catheter ablation were performed in sinus rhythm, guided only by the recording of the activation potential of the fiber. RESULTS: Efficacy in ablation was achieved in all patients. The fibers were located in the right lateral region of the tricuspid ring in 3 patients, right posterolateral region in 2, and right anterolateral region in 1. A mean of 5.3±3 radiofrequency applications was performed. The mean fluoroscopy time was 46.6±25 minutes, and the mean duration of the procedure was 178.6±108 minutes. No complication occurred. In a mean 20-month follow-up, all patients were asymptomatic and receiving no antiarrhythmic drugs. CONCLUSION: Catheter ablation of Mahaim fibers may be performed with good safety and efficacy by mapping the activation potential of the tricuspid ring in sinus rhythm.

Production and quality of cotton fibers in relation to solar radiation

The present paper refers to a research work carried out at the Dept. of Agriculture and Horticulture of ESALQ, University of São Paulo, in Piracicaba, State of São Paulo (latitude 22º42'S, longitude 47º33' WG and altitude 546 m). Sowing at different times and using artificial cover, an attempt was made to evaluate the behavior of cultivar IAC 17 of cotton (Gossypium hirsutum L.) as to production and quality of fiber relating to incident solar radiation. Incident solar radiation, as well as insolation during the trial period, were tabulated and compared with yelds and agricultural and technological characters of fibers. The treatment under cover showed a mean level of incident solar radiation equivalent to less than 20% of that at clear sky, causing a decrease in cotton production and in the agricultural and technological characters of fibers.

Synthesis and characterization of activated carbon fibers from Kevlar

Kevlar [poly (p-phenilylene terephtalamide)], was used as a precursor in the preparation of activated carbon fibers. For this intention, physical and chemical activations were carried out. Activated fibers were physically prepared from the carbonization of the Kevlar and its later activation with CO2 and steam of water, by the other hand; the chemically activated fibers were obtained by means of the impregnation of the material with phosphoric acid and their later carbonization. Different conditions were used and preliminary analyses of the precursor were taken into account (TGA-DTA / IR). The resulting fibers were characterized by N2 (77K) adsorption, infrared spectroscopy, SEM, and immersion calorimetry. Yields and Burn off were also evaluated. The results shows that if you want to synthesize activated carbon fibers from Kevlar strong conditions respect to the commonly used such as water steam, high phosphoric acid concentrations and methods of impregnation are the ones who allows the development of optimal surface areas and pore volumes.

Impaired regeneration of dystrophin-deficient muscle fibers is caused by exhaustion of myogenic cells

Duchenne muscular dystrophy is one of the most devastating myopathies. Muscle fibers undergo necrosis and lose their ability to regenerate, and this may be related to increased interstitial fibrosis or the exhaustion of satellite cells. In this study, we used mdx mice, an animal model of Duchenne muscular dystrophy, to assess whether muscle fibers lose their ability to regenerate after repeated cycles of degeneration-regeneration and to establish the role of interstitial fibrosis or exhaustion of satellite cells in this process. Repeated degenerative-regenerative cycles were induced by the injection of bupivacaine (33 mg/kg), a myotoxic agent. Bupivacaine was injected weekly into the right tibialis anterior muscle of male, 8-week-old mdx (N = 20) and C57Bl/10 (control, N = 10) mice for 20 and 50 weeks. Three weeks after the last injection, the mice were killed and the proportion of regenerated fibers was counted and reported as a fibrosis index. Twenty weekly bupivacaine injections did not change the ability of mdx muscle to regenerate. However, after 50 weekly bupivacaine injections, there was a significant decrease in the regenerative response. There was no correlation between the inability to regenerate and the increase in interstitial fibrosis. These results show that after prolonged repeated cycles of degeneration-regeneration, mdx muscle loses its ability to regenerate because of the exhaustion of satellite cells, rather than because of an increase in interstitial fibrosis. This finding may be relevant to cell and gene therapy in the treatment of Duchenne muscular dystrophy.

Changes in types of muscle fibers induced by transcutaneous electrical stimulation of the diaphragm of rats

The objective of the present study was to assess the effect of transcutaneous electrical diaphragmatic stimulation (TEDS) on different types of diaphragm muscle fibers. Male Wistar rats (8-12 weeks old) were divided into 2 experimental groups (N = 8 in each group): 1) control, 2) animals submitted to TEDS [frequency = 50 Hz; T ON/T OFF (contraction/relaxation time) = 2/2 s; pulse duration = 0.4 ms, intensity = 5 mA with a 1 mA increase every 3 min for 20 min] for 7 days. After completing this treatment period, the I, IIA, IIB, and IID diaphragm muscle fibers were identified using the mATPase technique. Statistical analysis consisted of the normality, homoscedasticity and t-tests (P < 0.05). There was a 19.6% (P < 0.05) reduction in the number of type I fibers and a 49.7% increase (P < 0.05) in type IID fibers in the TEDS group compared with the control group. An important result of the present study was that electrical stimulation with surface electrodes was efficient in altering the distribution of fibers in diaphragm muscle. This therapeutic resource could be used in the treatment of respiratory muscle alterations.

Three days of intermittent stretching after muscle disuse alters the proteins involved in force transmission in muscle fibers in weanling rats

The aim of this study was to determine the effects of intermittent passive manual stretching on various proteins involved in force transmission in skeletal muscle. Female Wistar weanling rats were randomly assigned to 5 groups: 2 control groups containing 21- and 30-day-old rats that received neither immobilization nor stretching, and 3 test groups that received 1) passive stretching over 3 days, 2) immobilization for 7 days and then passive stretching over 3 days, or 3) immobilization for 7 days. Maximal plantar flexion in the right hind limb was imposed, and the stretching protocol of 10 repetitions of 30 s stretches was applied. The soleus muscles were harvested and processed for HE and picrosirius staining; immunohistochemical analysis of collagen types I, III, IV, desmin, and vimentin; and immunofluorescence labeling of dystrophin and CD68. The numbers of desmin- and vimentin-positive cells were significantly decreased compared with those in the control following immobilization, regardless of whether stretching was applied (P<0.05). In addition, the semi-quantitative analysis showed that collagen type I was increased and type IV was decreased in the immobilized animals, regardless of whether the stretching protocol was applied. In conclusion, the largest changes in response to stretching were observed in muscles that had been previously immobilized, and the stretching protocol applied here did not mitigate the immobilization-induced muscle changes. Muscle disuse adversely affected several proteins involved in the transmission of forces between the intracellular and extracellular compartments. Thus, the 3-day rehabilitation period tested here did not provide sufficient time for the muscles to recover from the disuse maladaptations in animals undergoing postnatal development.