Mouse extensor digitorum longus and soleus show distinctive ultrastructural changes induced by veratrine

We investigated whether veratrine (5 μl, 10 ng/kg) injected into the mouse extensor digitorum longus (EDL) (fast-twitch) and soleus (SOL) (slow-twitch) muscles provokes distinctive ultrastructural disturbances 15, 30 and 60 min later. The mitochondria in SOL were affected earlier (within 15 min) than in EDL. Swelling of the sarcoplasmic reticulum terminal cisternae was more marked in EDL than in SOL and caused distortion of sarcomeres so that fragmentation of myofilaments was more pronounced in EDL. Hypercontracted sarcomeres were seen mainly in SOL and veratrine caused infoldings of the sarcolemma only in this muscle. In both muscles, the T-tubules remained unaffected and by 60 min after veratrine most of the above alterations had reverted to normal. Pretreatment with tetrodotoxin prevented the alterations induced by veratrine. This suggests that most of the alterations resulted from the enhanced influx of Na+ into muscle fibers. These results emphasize the importance of considering the type of muscle when studying the action of myotoxic agents.

Períodes de controle de Brachiaria sp e seus reflexos na produtividade de Eucalyptus grandis

A field trial was conduced in Piratininga, São Paulo State, Brazil, from August to 1991 to May 1999, aiming to study the effects of weed interference on the productivity of Eucalyptus grandis W. Hill Ex Maiden. The experimental design was complete randomized blocks with four replications. The treatments consisted of different extensions and times of the weed free period. The weed free periods were divided in two groups. In the first one, the weed free period were from the Eucalyptus planting to 28, 56, 112, 140, 168, 224, 278 and 360 days. In the second group the weed free period began at 0, 28, 56, 112, 140, 168, 224 and 278 days after the planting and finished at 364 days. The main weeds were Brachiaria decumbens and Brachiaria brizantha. The eucalypt plants were strong susceptive at weed interference at 12 months after planting, it was showing PAI of 12 and 6 days, when to consider 2 and 5% reduction on height. Although, to assure crop productivity at Piratininga it was necessary to maintain a weed free period of to 364 and 365 days after planting (PTPI) at 12 months, 194 and 166 days after planting at 24 months, 188 and 130 days after planting at 36 months, 88 and 54 days after planting at 48 months and 155 and 133 days after planting at 78 months, when to consider 2 an 5% reduction on heigth. But, if when to consider the DAP, the PTPI was 242 and 200 days after planting at 24 months, 208 and 153 days after planting at 36 months, 224 and 150 days after planting at 48 months and 134 and 119 days after planting at 78 months. Although when to consider the wood volume it was necessary to keep the weed free from the planting to 153 and 142 days at 36 months after planting, 99 and 91 days at 48 months after planting and 92 and 72 days at 78 months after planting (crop). However, in area to suggest the recuperation the eucalypt plants at weed Interference.

Morphological aspects of muscle regeneration in the Nile tilapia (Oreochromis niloticus)

The aim of our study was to analyze the morphological events in the skeletal muscle of the Nile tilapia (Oreochromis niloticus) after a traumatic lesion. Thirty-two fish were used, on which a small longitudinal incision was made in the muscle. The fish were sacrificed after 7, 14, 21, and 42 days and muscle samples were collected from the lesion and processed for morphological analysis. Muscle regeneration in the tilapia occurred gradually through the analyzed period, possibly due to the proliferation and differentiation of myosatellite cells, which were more morphologically evident 7 and 14 days after lesion.

Heart failure alters MyoD and MRF4 expressions in rat skeletal muscle

Heart failure (HF) is characterized by a skeletal muscle myopathy with increased expression of fast myosin heavy chains (MHCs). The skeletal muscle-specific molecular regulatory mechanisms controlling MHC expression during HF have not been described. Myogenic regulatory factors (MRFs), a family of transcriptional factors that control the expression of several skeletal muscle-specific genes, may be related to these alterations. This investigation was undertaken in order to examine potential relationships between MRF mRNA expression and MHC protein isoforms in Wistar rat skeletal muscle with monocrotaline-induced HF. We studied soleus (Sol) and extensor digitorum longus (EDL) muscles from both HF and control Wistar rats. MyoD, myogenin and MRF4 contents were determined using reverse transcription-polymerase chain reaction while MHC isoforms were separated using polyacrylamide gel electrophoresis. Despite no change in MHC composition of Wistar rat skeletal muscles with HF, the mRNA relative expression of MyoD in Sol and EDL muscles and that of MRF4 in Sol muscle were significantly reduced, whereas myogenin was not changed in both muscles. This down-regulation in the mRNA relative expression of MRF4 in Sol was associated with atrophy in response to HF while these alterations were not present in EDL muscle. Taken together, our results show a potential role for MRFs in skeletal muscle myopathy during HF. © 2006 Blackwell Science Ltd.

Levedura íntegra e derivados do seu processamento em rações para tilápia do Nilo: Aspectos hematológicos e histológicos

The effects of inclusion of whole yeast, autolyzed yeast and yeast cell wall on hematological parameters and gut villus perimeter were evaluated in juvenile Nile tilapia, after 80 experimental days. Isoproteic (32.0% DP) and isoenergetic (3200 kcal DE kg -1) practical diets were supplemented with three levels of whole yeast or autolyzed yeast (1.0, 2.0 and 3.0%) and three levels of yeast cell wall (0.1, 0.2 and 0.3%), plus a control diet (with no test microingredients). Red blood cell count, hemoglobin concentration, total plasmatic protein, hematocrit percentage, mean corpuscular volume, mean corpuscular hemoglobin concentration and gut villus perimeter were evaluated. Variations on hematological parameters in animals fed diets with whole yeast; autolyzed yeast and yeast cell wall were observed to be within normal ranges for this species. There was significant influence (p<0.05) of different levels of yeast and derivatives on intestinal villus perimeter. Results showed that experimental period and proposed levels of whole yeast, autolyzed yeast and yeast cell wall do not provide undesirable alterations on standard hematological parameters to Nile tilapia and can be safely used to compound diets for this species. Results also showed that supplement of yeast cell wall provide higher intestinal villus perimeter.

Localização histoquímica de algumas hidrolases no epidídimo do gerbilo

This study mainly showed that alkaline phosphatase expression had been present in the proximal regions of the epididymidis ductus of the gerbil which comprised the initial segment and proximal caput. The reactivities of acid phosphatase and ATPase were strong in the proximal and distal regions of the epididymidis ductus at the level of the apical cytoplasm and epithelium, except at the corpus level, a very thin isthmus located between the caput and cauda epididymidis, and as a general rule a low enzymatic reactive region of the epididymis of gerbil. SDH revealed also low activities in all the regions and regional structures of the duct, except into the luminal content formed by storaged spermatozoa, prior on the cauda level. The enzymes presented in the epididymis were correlated to some histophysiological roles such as the enzymatic mediation of endocytosis, secretion, absorption and active transport concerning to phosphatases and ATPase and a possible mitochondrial role of SDH could occur at the spermatozoa level in which the middle pieces were formed by a great amount of mitochondria.

Morfologia e morfometria dos tipos de fibras do músculo reto abdominal de cadelas (canis familiaris) durante a gestação

The present paper deals with the evaluation of morphological and morphometric alterations of slow-twist (I) and fast-twitch (II) fibers of rectus abdominis muscle of adult female dog during pregestational phase, at 30 and 60 days of pregnancy and at 30 days after the parturition. At the every phases, using the open biopsy technique, muscle samples were collected. The samples were plunged. Histological sections were cut in a microtome. For general morphology, some sections were stained with HE. Subsequent sections were reacted for myofibrillar ATPase (m-ATPase), after alkaline (pH 10.4) and acid (pH 4.4) pre-incubations, in order to identificate type I and II fibers. In the pre-gestational phase, muscle tissue revealed to be composed by fibers with different diameters, presenting polygonal outlines and one or more periphery nuclei. At 30 days of pregnancy, muscle fiber characteristics were similar. At 60 days, in addition to the existence of normal fibers, polymorphic and small diameter fibers were frequent. At 30 days after the parturation, the morphology of muscle fiber were similar to that observed in the pre-gestational phase. In the four phases, type II fiber diameters were lager than type I. The diameters of both fiber types showed a significant reduction in the 30 days phase and a significative increasing at 60 days. The expansion of the abdominal wall during the pregnancy represents a chronic stimulus, induced changes in the morphology and in the fiber type diameters.

Desmoplastic small round cell tumor of the kidney mimicking wilms tumor: A case report and review of the literature

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive, malignant neoplasm usually present with the widespread abdominal serosal involvement and affects mainly adolescents and young adults. When presenting within visceral organs, as kidney, the diagnosis of DSRCT imposes significant difficulties. We present a case of primary DSRCT of the kidney in a 10-year-old boy mimicking clinically and pathologically Wilms tumor. The tumor showed morphologic and immunohistochemical features of DSRCT and the presence of the Ewing sarcoma and Wilm tumor 1 fusion transcripts resulting from the t(11;22) (p13;q12) reciprocal translocation. DSRCT should be considered in the differential diagnosis of Wilm tumor and other small blue-round cell tumors of the kidney. © 2009 by Lippincott Williams & Wilkins.

A comparative study of myocardial function and morphology during fasting/refeeding and food restriction in rats

Background: This study compared the influence of fasting/refeeding cycles and food restriction on rat myocardial performance and morphology. Methods: Sixty-day-old male Wistar rats were submitted to food ad libitum (C), 50% food restriction (R50), and fasting/refeeding cycles (RF) for 12 weeks. Myocardial function was evaluated under baseline conditions and after progressive increase in calcium and isoproterenol. Myocardium ultrastructure was examined in the papillary muscle. Results: Fasting/refeeding cycles maintained rat body weight and left ventricle weight between control and food-restricted rats. Under baseline conditions, the time to peak tension (TPT) was more prolonged in R50 than in RF and C rats. Furthermore, the maximum tension decline rate (-dT/dt) increased less in R50 than in RF with calcium elevation. While the R50 group showed focal changes in many muscle fibers, such as the disorganization or loss of myofilaments, polymorphic mitochondria with disrupted cristae, and irregular appearance or infolding of the plasma membrane, the RF rats displayed few alterations such as loss or disorganization of myofibrils. Conclusion: Food restriction promotes myocardial dysfunction, not observed in RF rats, and higher morphological damage than with fasting/refeeding. The increase in TPT may be attributed possibly to the disorganization and loss of myofibrils; however, the mechanisms responsible for the alteration in -dT/dt in R50 needs to be further clarified. © 2010 Elsevier Inc. All rights reserved.

Numerical correction for the diffuse solar irradiance by the melo-escobedo shadowring measuring method

The present paper deals with numerical corrections factors proposed as a function of the clearness index in order to correct the diffuse solar irradiance measured with the Melo-Escobedo Shadowring Measuring Method (ME shadowring). The global irradiance was measured by an Eppley - PSP pyranometer ; direct normal irradiance by an Eppley-NIP pyrheliometer fitted to a ST-3 sun tracking device and the diffuse irradiance by an Eppley-PSP pyranometer fitted to a ME shadowring. The validations were performed by the MBE and RMSE statistical indicators. The results showed that the numerical correction factors were appropriate to correct the shadowring diffuse irradiance.

Short periods of fasting followed by refeeding change the expression of muscle growth-related genes in juvenile Nile tilapia (Oreochromis niloticus)

Muscle growth mechanisms are controlled by molecular pathways that can be affected by fasting and refeeding. In this study, we hypothesized that short period of fasting followed by refeeding would change the expression of muscle growth-related genes in juvenile Nile tilapia (Oreochromis niloticus). The aim of this study was to analyze the expression of MyoD, myogenin and myostatin and the muscle growth characteristics in the white muscle of juvenile Nile tilapia during short period of fasting followed by refeeding. Juvenile fish were divided into three groups: (FC) control, feeding continuously for 42. days, (F5) 5. days of fasting and 37. days of refeeding, and (F10) 10. days of fasting and 32. days of refeeding. At days 5 (D5), 10 (D10), 20 (D20) and 42 (D42), fish (n = 14 per group) were anesthetized and euthanized for morphological, morphometric and gene expression analyses. During the refeeding, fasted fish gained weight continuously and, at the end of the experiment (D42), F5 showed total compensatory mass gain. After 5 and 10. days of fasting, a significant increase in the muscle fiber frequency (class 20) occurred in F5 and F10 compared to FC that showed a high muscle fiber frequency in class 40. At D42, the muscle fiber frequency in class 20 was higher in F5. After 5. days of fasting, MyoD and myogenin gene expressions were lower and myostatin expression levels were higher in F5 and F10 compared to FC; at D42, MyoD, myogenin and myostatin gene expression was similar among all groups. In conclusion, this study showed that short periods of fasting promoted muscle fiber atrophy in the juvenile Nile tilapia and the refeeding caused compensatory mass gain and changed the expression of muscle growth-related genes that promote muscle growth. These fasting and refeeding protocols have proven useful for understanding the effects of alternative warm fish feeding strategies on muscle growth-related genes. © 2013.

NFAT isoforms regulate muscle fiber type transition without altering can during aerobic training

The purpose of this study was to determine whether the aerobic training-induced fiber-type transition in different muscles is associated with alterations in NFAT isoforms gene expression. We hypothesized that the aerobic training-induced fiber-type transition would be mediated by NFATc1-c3 isoforms without altering the CaN expression. Male Wistar rats (80 days old) were divided into a trained group (T; n=8) that underwent an 8-wk swimming endurance training program (5 days/week) and a control group (C; n=8). After the experimental period, the animals were sacrificed, and the soleus (SOL) and plantaris (PL) muscles were collected for morphometrical, histochemical and molecular analyses. Aerobic training induced a type I-to-type IIA fiber transition in the SOL muscle and a type IIB-to-type IIA fiber transition in the PL muscle, which were concomitant with a significant (p<0.05) increase in NFATc1-c3 gene expression in both the SOL and PL muscles. In contrast, the expression levels of calcineurin (CaN) and NFATc4 remained unchanged. Therefore, our results showed that fiber type switching induced by aerobic training is mediated by NFATc1-c3 isoforms without altering the CaN expression. © Georg Thieme Verlag KG Stuttgart. New York.

Influéncia da adubação nitrogenada sobre a interferéncia de plantas daninhas em feijoeiro1

The competition between weeds and bean plants, especially because of nutrients in the environment, is extremely important to minimize potential losses of crop productivity. Thus, the aim of this work was to evaluate the effects of using nitrogen fertilization on the timing and extent of the period before interference (PAI), total period of interference (PTPI) and the critical period of interference control (PCPI) in bean cultivar 'Ruby'. The seeds were sown in the conventional system and the trial was conducted in two areas at the same time, in which the nitrogen fertilization was performed only in one of them. Each area received 14 treatments consisting of two groups: first, the crop was free of interference of weeds from emergence to 10, 20, 30, 40, 50, 60 and 70 days; and the second: the crop remained free of interference from sowing to the same periods described above. The experimental design was randomized blocks with four replications. Raphanus raphanistrum showed greater relative importance in the two areas, mainly due to the accumulation of dry mass, followed by Amaranthus deflexus. There was no difference in diversity and evenness of weed populations in response to the fertilization. In the area without N PAI occurred 18 days after emergence (DAE), and up to 24 DAE PTPI, resulting in PCPI 18 to 24 DAE, this area had 58% of reduction in crop yield. In the area where with nitrogen fertilization, PAI occurred at 38 DAE and PTPI occurred at 19 DAE. In this area there was 56% of reduction in crop yield. The nitrogen fertilization increased crop productivity and favored competitiveness in relation to weeds.

Extensive impact of saturated fatty acids on metabolic and cardiovascular profile in rats with diet-induced obesity: A canonical analysis

Background: Although hypercaloric interventions are associated with nutritional, endocrine, metabolic, and cardiovascular disorders in obesity experiments, a rational distinction between the effects of excess adiposity and the individual roles of dietary macronutrients in relation to these disturbances has not previously been studied. This investigation analyzed the correlation between ingested macronutrients (including sucrose and saturated and unsaturated fatty acids) plus body adiposity and metabolic, hormonal, and cardiovascular effects in rats with diet-induced obesity. Methods: Normotensive Wistar-Kyoto rats were submitted to Control (CD; 3.2 Kcal/g) and Hypercaloric (HD; 4.6 Kcal/g) diets for 20 weeks followed by nutritional evaluation involving body weight and adiposity measurement. Metabolic and hormonal parameters included glycemia, insulin, insulin resistance, and leptin. Cardiovascular analysis included systolic blood pressure profile, echocardiography, morphometric study of myocardial morphology, and myosin heavy chain (MHC) protein expression. Canonical correlation analysis was used to evaluate the relationships between dietary macronutrients plus adiposity and metabolic, hormonal, and cardiovascular parameters. Results: Although final group body weights did not differ, HD presented higher adiposity than CD. Diet induced hyperglycemia while insulin and leptin levels remained unchanged. In a cardiovascular context, systolic blood pressure increased with time only in HD. Additionally, in vivo echocardiography revealed cardiac hypertrophy and improved systolic performance in HD compared to CD; and while cardiomyocyte size was unchanged by diet, nuclear volume and collagen interstitial fraction both increased in HD. Also HD exhibited higher relative β-MHC content and β/α-MHC ratio than their Control counterparts. Importantly, body adiposity was weakly associated with cardiovascular effects, as saturated fatty acid intake was directly associated with most cardiac remodeling measurements while unsaturated lipid consumption was inversely correlated with these effects. Conclusion: Hypercaloric diet was associated with glycemic metabolism and systolic blood pressure disorders and cardiac remodeling. These effects directly and inversely correlated with saturated and unsaturated lipid consumption, respectively. © 2013 Oliveira Junior et al.; licensee BioMed Central Ltd.

Expression of genes related to quality of Longissimus dorsi muscle meat in Nellore (Bos indicus) and Canchim (5/8 Bos taurus×3/8 Bos indicus) cattle

This study was performed to compare CAPN1, CAPN2, CAST, TG, DGAT1 and LEP gene expressions and correlate them with meat quality traits in two genetic groups (Nellore and Canchim) in order to assess their expression profile and use their expression profile as genetic markers. We analyzed 30 young bulls (1. year old), 15 of each genetic group. Samples of the Longissimus dorsi muscle were collected for analysis of: total lipids (TL) and meat tenderness measured as Warner-Bratzler shear force (SF) and myofibrillar fragmentation (MFI) at day of slaughter and 7. days of aging. Gene expression profiles were obtained via RT-qPCR. TL and MFI showed differences between breeds, higher MFI in Canchim and higher TL in Nellore. Calpains showed no differential expression between groups, as did DGAT1, TG, and LEP. CAST was expressed more in the Nellore cattle. The only significant within-breed correlation (0.79) between gene expression and meat traits was found for DGAT1 and MFI in Canchim breed. Although the number of animals used in this study was small, the results indicate that the increased expression of CAST in Nellore may reflect tougher meat, but the lack of correlations with the meat traits indicates it is not a promising genetic marker. © 2013 Elsevier Ltd.