Regional blood flow in conscious rats after head-down suspension

Exposure to microgravity in humans causes cardiovascular deconditioning affecting blood pressure, heart rate and vascular responsiveness. This study investigated cardiac output, arterial blood pressure and regional blood flows [radioactive microspheres: ⁵⁷Co, 15.5 (SEM 0.1) μm in diameter] in conscious and freely moving rats subjected to 14 days of simulated microgravity (head-down suspension, HDS) in male Wistar rats: control (horizontally attached, n = 7), suspended for 14 days (n = 8) and suspended/allowed to recover for 10 min (R10min, n = 5) or 24 h (n = 9). Compared to the control group, 14 days of HDS resulted in reduced total peripheral resistance (37%); an increased cardiac index (65%) was associated with no significant change in the mean arterial pressure . There were elevated brain (63%), visceral (>20%), hindlimb (>80%) and forelimb (>215%) muscle blood flows. In the R10min group, the decreased (18%) and the regional blood flows returned to control values. Within 24 h the as well as cardiac index and total peripheral resistance were restored. In conclusion, 14 days of HDS engendered local circulatory changes resulting in transient blood pressure instability during recovery. Accepted: 26 March 1998     

Treadmill exercise suppresses muscle cell apoptosis by increasing nerve growth factor levels and stimulating p-phosphatidylinositol 3-kinase activation in the soleus of diabetic rats

We investigated the effects of treadmill exercise performed regularly for 6 weeks on the levels of nerve growth factor (NGF), tyrosine kinase A and p75 receptors, phosphatidylinositol 3-kinase (PI3-K), mitogen-activated protein kinase/extracellular signal-regulated kinase (Erk) 1,2, cyclic AMP response element-binding protein (CREB), and caspase-3 in the soleus of rats with streptozotocin (STZ)-induced diabetes. Thirty-two male Sprague–Dawley rats were divided into the following four groups: (1) normal control group (NCG; n = 8), (2) normal exercise group (NEG; n = 8), (3) diabetes control group (DCG; n = 8), and (4) diabetes exercise group (DEG; n = 8). Diabetes was induced by intraperitoneal injection of STZ (55 mg/kg dissolved in 0.05 M citrate buffer, pH 4.5). Rats were subjected to treadmill exercise 5 days a week for 6 weeks. The protein level of NGF significantly increased in the NEG and DEG (p < 0.001), whereas the levels of tyrosine kinase A and p75 receptors significantly increased in the NEG (p < 0.001). The levels of t-PI3-K, p-PI3-K, and p-CREB, and the p-CREB/t-CREB ratio significantly increased in the NEG (p < 0.001, respectively). The p-PI3-K/t-PI3-K ratio significantly increased in the DEG (p < 0.001). The p-Erk1/t-Erk1 ratio significantly increased in the NEG (p < 0.001), whereas the p-Erk2/t-Erk2 ratio significantly decreased in the DCG and DEG (p < 0.001). The caspase-3 level significantly increased in the DCG compared with that in the DEG (p < 0.001). These results suggest that treadmill exercise increases NGF levels and accelerates p-PI3-K activation in order to suppress apoptotic cell death in the soleus muscle of diabetic rats.     

Serum and Cerebrospinal Fluid Magnesium Levels, Glasgow Coma Scores, and In-Hospital Mortality in Patients with Acute Stroke

The aim of this study was to determine the relationship between serum and cerebrospinal fluid (CSF) magnesium (Mg⁺²) levels, Glasgow Coma Scores (GCS), and 7-day mortality in acute stroke patients. Patients with acute ischemic or hemorrhagic stroke arriving within the first 3 h of symptoms were included in the study. The control group consisted of healthy volunteers. GCS was determined, and blood and CSF samples were taken in order to establish serum and CSF glucose, Mg⁺², sodium, potassium, calcium, and chlorine levels. Mortality was recorded at 7 days after admission. CSF Mg⁺² in the ischemic infarct group was significantly lower than in the control group (p = 0.006). CSF Mg⁺² in the ischemic infarct patients with a GCS ≤ 8 were significantly lower (p = 0.002) than controls and in ischemic infarct patients with a GCS ≥9. In the ischemic stroke patients, CSF Mg⁺² and GCS were significantly correlated (r = 55, p = 0.031). CSF Mg⁺² levels in ischemic stroke patients who died within 7 days were significantly lower than controls, ischemic stroke patients who survived, and hemorrhagic stroke patients who died (p = 0.002, p = 0.042, and p = 0.005, respectively). Low CSF Mg⁺² levels in patients with acute ischemic stoke at admission predicted a higher 1-week mortality.     

Highly efficient plant regeneration and <Emphasis Type="Italic">in vitro</Emphasis> polyploid induction using hypocotyl explants from diploid mulberry (<Emphasis Type="Italic">Morus multicaulis</Emphasis> Poir.)

Efficient plant regeneration is essential for successful transformation and in vitro polyploidy induction in mulberry. A high frequency (80%) of plant regeneration from hypocotyls occurred under in vitro conditions in mulberry (Morus multicaulis Poir.). We identified three key factors for enhancing successful regeneration based on earlier work: (1) hypocotyl position, (2) the combination and concentration of growth regulators, and (3) the addition of AgNO₃. The highest frequency of shoot regeneration was achieved using hypocotyl segments, which are proximal to apical meristems, and the optimal culture conditions were Murashige and Skoog’s (MS) (Murashige and Skoog, 1962) basal medium supplemented with 3.0 mg l⁻¹ 6-benzylamino purine, 0.3 mg l⁻¹ indole-3-acetic acid, 0.1% polyvinypyrrolidone, and 1.0 mg/l silver nitrate (AgNO₃) under subdued light at 25 ± 2°C. Treating the shoots with 0.2% colchicine (dipping for 72 h) resulted in a 14% tetraploid frequency, whereas a 20% tetraploid frequency resulted from using a 0.25% colchicine (dripping for 5 d) treatment, as determined by chromosome number counts. The diploid plant chromosome number was 28 (2n = 2x = 28) and that of tetraploid plants was 56 (2n = 4x = 56). Regenerated shoots rooted easily in 8–10 d using half-strength basal MS medium with 0.5 mg l⁻¹ indole-3-butyric acid and were successfully established in the soil.     

Effect of Selenium Pre-treatment on Antioxidative Enzymes and Lipid Peroxidation in Cd-exposed Suckling Rats

Since there are no data about the protective role of selenium (Se) against cadmium (Cd)-induced oxidative damage in early life, we studied the effect of Se supplementation on antioxidative enzyme activity and lipid peroxidation (through thiobarbituric acid reactive substances; TBARS) in suckling Wistar rats exposed to Cd. Treated animals received either Se alone for 9 days (8 μmol, i.e., 0.6 mg Se as Na₂SeO₃ kg⁻¹ b.w., daily, orally; Se group), Cd alone for 5 days (8 μmol, i.e., 0.9 mg Cd as CdCl₂ kg⁻¹ b.w., daily, orally; Cd group), or pre-treatment with Se for 4 days and then co-treatment with Cd for the following 5 days (Se + Cd group). Our results showed that selenium supplementation, with and without Cd, increased SOD activity in the brain and kidney, but not in the liver and GSH-Px activity across all tissues compared to control rats receiving distilled water. Relative to the Cd group, Se + Cd group had higher kidney and brain SOD and GSH-Px activity (but not the liver), while in the liver caused increased and in the brain decreased TBARS level. These results suggest that Se stimulates antioxidative enzymes in immature kidney and brain of Cd-exposed rats and could protect against oxidative damage.     

Downregulation of Apoptosis and Modulation of TGF-β1 by Sodium Selenate Prevents Streptozotocin-Induced Diabetic Rat Renal Impairment

To investigate whether sodium selenate treatment would impact on the onset of diabetic nephropathy, we examined blood glucose, serum biochemical components, and interrelationship between oxidative stress, TGF-β1, and apoptosis in streptozotocin (STZ) induced diabetic rats. Sixty male Wistar rats were divided into six groups. Group I (n = 10), normal control; Group II (n = 10), diabetic control; Group III (n = 10), sodium selenate (16 μmoles/kg) + diabetic; Group IV (n = 10), sodium selenate (32 μmoles/kg) + diabetic; Group V (n = 10), sodium selenate (16 μmoles/kg) control; and Group VI (n = 10), sodium selenate (32 μmoles/kg) control. Sodium selenate was administered via orogastric route for 10 weeks. In the diabetic group, diabetes was induced by single intraperitoneal injection of STZ (50 mg/kg). The levels of blood glucose were estimated and total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, creatinine, urea, and albumin were detected in serum. Antioxidant status was examined by measuring the superoxide dismutase (SOD), catalase, glutathione, and lipid peroxidation in kidney tissues. Histopathological studies were performed in the kidney tissue sections. The expression of TGF-β1 was estimated by the immunohistochemical analysis in kidneys. Apoptotic study in kidney was performed using the TdT-mediated dUTP nick end labeling technique. It was observed that blood glucose, serum, total cholesterol, HDL cholesterol, triglycerides, creatinine, urea, and albumin were significantly higher in diabetic control groups. Diabetic + sodium selenate (16 and 32 μmoles/kg) significantly reduced blood glucose, serum, total cholesterol, HDL cholesterol, triglycerides, creatinine, urea, and albumin levels. Selenium-treated groups significantly increased antioxidant enzyme activities (SOD, catalase, and glutathione) in kidneys of diabetic rats. All enzyme activities of selenium control groups did not differ compared with the normal control. Sodium selenate reduces significantly lipid peroxidation in diabetic rats. Cellular architecture of the diabetic rats was altered whereas sodium selenate administration rectifies the degenerative changes of the kidney. Profound immunopositivity of TGF-β1 was observed in the glomerular and tubulointerstitial cells of diabetic rat kidney. Immunopositivity of TGF-β1 was significantly reduced in both low and high dose of sodium-selenate-treated rats (P < 0.05, P < 0.01). High numbers of apoptotic cells were observed in diabetic rats whereas sodium selenate in both doses significantly reduces the incidence of apoptosis (P < 0.05, P < 0.01). We conclude herein that sodium selenate has the potential to play a significant role in limiting the renal impairment by altering the apoptosis and TGF-β1 in experimental diabetic rats.     

Ranging behaviour and socio-biology of Eurasian otters (Lutra lutra) on lowland mesotrophic river systems

We examined the spatial structure and socio-biology of a native wild population of Eurasian otters (Lutra lutra) on mesotrophic rivers in a mild temperate climate. Radio-tracking of 20 individuals revealed exclusive intra-sexual adult home-ranges. Adult female home-ranges (7.5 km, SD = 1.5 km, n = 7) were inversely related to river width (, F ₆ = 13.5, P = 0.014) and so appeared to be based on food resources. The aquatic area within adult male home-ranges (30.2 ha, SD = 9.5 ha, n = 5) was greater than that within adult female’s (16.8 ha, SD = 7.0 ha) (t ₁₀ = 2.437, P = 0.035), though this result is inconclusive because some males were tracked on oligotrophic rivers. One adult male expanded its range from 10.2 km to 19.3 km within 5 days of the death of the neighbouring male, suggesting that male home-ranges were heavily influenced by conspecifics.     

Hemoglobin Regeneration Efficiency in Anemic Rats: Effects on Bone Mineral Composition and Biomechanical Properties

This study reports the effects of dietary iron (Fe) deficiency and recovery on bone mineral composition and strength in anemic rats submitted to a hemoglobin (Hb) repletion assay. Weanling male Wistar rats were fed a low-Fe diet (12 mg/kg) for 15 days followed by 2 weeks of Fe repletion with diets providing 35 mg Fe/kg as either ferrous sulfate (n = 8) or ferric pyrophosphate (FP; n = 12). At final day of each period (depletion and repletion), Fe-adequate animals were also euthanized. Iron status (blood Hb, Hb Fe pool, Hb regeneration efficiency), tibia mineral concentrations (Ca, Mg, Fe, Cu, and Zn) and biomechanical properties were evaluated. Iron-deficient rats had lower tibia Fe and Mg levels and bone strength when compared to controls. Yield load and resilience were positively related to tibia Mg levels (r = 0.47, P = 0.02 and r = 0.56, P = 0.004, respectively). Iron repletion did not recover tibia Mg concentrations impaired by Fe deficiency. Moreover, bone elastic properties were negatively affected by FP consumption. In conclusion, bone mineral composition and strength were affected by Fe deficiency, whereas dietary Fe source influenced tibia Mg and resistance in the period during which rats were recovering from anemia.     

Flow cytometry,with double staining with Nile red and anti-CD3 antibody,to detect phospholipidosis in peripheral blood lymphocytes of rats treated with amiodarone

A flow cytometry method, to monitor peripheral lymphocytes phospholipidosis, has been set up using a single staining with Nile red and double staining with Nile red and anti-CD3 monoclonal antibody. Blood has been collected from rats treated with amiodarone (phospholipidogenic antiarrhythmic drug). By flow cytometer, it is possible to detect phospholipids, using Nile red, a probe for intracellular lipids staining, changing its fluorescence on the stained lipid basis. CD3 antigen has been selected to focus on T cells, to evaluate whether these cells are the target of phospholipidosis amiodarone-dependent. In the study A, Sprague–Dawley rats were treated with three different doses (75, 150, and 300 mg kg⁻¹ day⁻¹) of amiodarone or vehicle alone, for 14 days, followed by 14 days of recovery: Data obtained show that by flow cytometry, with Nile red alone, it is possible to detect a dose- and time-related response of phospholipidosis-positive lymphocytes; a partial recovery is also assessed. In the study B, Sprague–Dawley rats were treated with a single dose (300 mg kg⁻¹ day⁻¹) of amiodarone, for 14 days: Data obtained show that animals treated with amiodarone have a significant increase of phospholipidosis-positive lymphocytes (p = 0.008), in particular of CD3⁺ cells (p = 0.0056). Transmission electron microscopy analysis confirmed data obtained by flow cytometry. This work shows that flow cytometry with Nile red could be a good tool to monitor ex vivo phospholipidosis in lymphocyte cells of animals treated with amiodarone: The phospholipidogenic effect is more evident focusing on CD3⁺ T lymphocytes, thus suggesting that these cells are probably the target of phospholipidosis.     

Plasma Zinc,Copper, and Serum Thyroid Hormones and Insulin Levels After Zinc Supplementation Followed by Placebo in Competitive Athletes

Intense physical activity is associated with biological adaptations involving hormones and trace elements. Zinc supplementation may affect plasma copper concentration, thyroid-stimulating hormone (TSH), thyroid hormones, insulin, and glucose homeostasis, but data in athletes are scarce. The aim of this study was to evaluate in competitive athletes (cyclists, n = 7, 32 ± 8 years) the effect of zinc supplementation (22 mg/day as zinc gluconate) during 30 days, and discontinuation using placebo (maltodextrin) during the following 30 days, on plasma zinc and copper concentrations, serum thyroid hormones, insulin and glucose levels, and HOMA2-IR. Compared to baseline, plasma zinc and Zn:Cu plasma ratio increased, but plasma copper decreased after zinc supplementation (day 30) and discontinuation (day 60) (p < 0.05). Zn supplementation and discontinuation had no effect on TSH, T3, and T4. Fasting serum insulin and HOMA2-IR increased (27% and 47%, respectively) on day 60 compared to baseline (p = 0.03), suggesting a delayed effect of zinc supplementation. Moreover, plasma zinc was positively associated with serum insulin (r = 0.87, p = 0.009) and HOMA2-IR (r = 0.81, p = 0.03) after zinc supplementation (day 30), indicating that supplemental zinc may impair glucose utilization in cyclists.     

In vitro induction of a trisomic of Agave tequilana Weber var. Azul (Agavaceae) by para-fluorophenylalanine treatment

The effect of para-fluorophenylalanine (PFP) on the production of trisomic plants of Agave tequilana Weber var. Azul produced through somatic embryogenesis was investigated. Normal diploid plants with 2n = 2x = 60 were obtained in the control treatment and with 4 mg L⁻¹ PFP exposure, while use of 8 and 12 mg L⁻¹ PFP led to production of trisomics with 2n = 2x = 61. Normal diploid plants showed a bimodal karyotype with five pairs of large chromosomes and 25 pairs of small chromosomes. Trisomic plants also had a bimodal karyotype with a group of three chromosomes in position five of the chromosome set. More than 13 homologous chromosome pairs exhibited structural changes. Differences in chromosome arm ratio (long arm/short arm) were also found in eight chromosome pairs; all these aberrations in the chromosome complement of trisomic plants were probably caused by inversions, deletions, and/or duplications produced by high concentrations of PFP. The gross chromosome structural changes and the presence of a single extra chromosome could have been induced by the effect of PFP on the mitotic spindle by inducing nondisjunction of sister chromatids, resulting in hyperploids (2n + x) and hypoploids (2n − x). Flow cytometric analysis of nuclear DNA content was performed using nuclei isolated from young leaves of normal and trisomic plants. The 2C DNA content of 8.635 pg (1Cx = 4,223 Mbp of trisomic plants was different (p < 0.001) than that of normal plants (2C DNA = 8.389 pg (1Cx = 4,102 Mbp). The difference in genome size was correlated with the large structural changes in the trisomic plant genomes.     

Regulation of adiponectin gene expression in adipose tissue by thyroid hormones

Available experimental data suggest that adiponectin and thyroid hormones have biological interaction in vivo. However, the effects of thyroid hormones on adipose adiponectin gene expression in thyroid dysfunction are unclear. We induced hyper- (HYPER) and hypothyroidism (HYPO) by daily administration of a 12 mg/l of levothyroxine and 250 mg/l of methimazole in drinking water of rats, respectively, for 42 days. The white adipose tissues and serum sample were taken on days 15, 28, 42 and also 2 weeks after treatment cessation. Analysis of adiponectin gene expression was performed by real-time PCR and 2^−ΔΔct method. The levels of adipose tissue adiponectin mRNA in the HYPO rats were decreased during the 6-week treatment when compared to control rats (<0.05) and were increased significantly 2 weeks after HYPO cessation (P < 0.05). This decline in adiponectin gene expression occurred in parallel with a decrease in T3, T4, fT3 and fT4 concentrations (P < 0.05). In opposite to HYPO rats, adipose adiponectin gene expression was increased in HYPER rats during the 6-week treatment in parallel with an increase the thyroid hormones concentrations (P < 0.05), and its expression was decreased 2 weeks after HYPER cessation (P < 0.05). Adiponectin gene expression levels showed significant negative correlations with concentrations of LDL (HYPO; r = −0.806, P = 0.001 and HYPER; r = −0.749, P = 0.002), triglyceride (HYPO; r = −0.825, P = 0.001 and HYPER; r = −0.824, P = 0.001) and significant positive correlations with concentrations of glucose (HYPO; r = 0.674, P = 0.004 and HYPER; r = 0.866, P = 0.001) and HDL (HYPO; r = 0.755, P = 0.001 and HYPER; r = 0.839, P = 0.001). The current study provides evidence that adiponectin gene expression in adipose tissue is regulated by thyroid hormones at the translation level and that lipid and carbohydrate disturbances in a patient with thyroid dysfunction may be, in part, due to adiponectin gene expression changes.     

Changes in Serum Zinc Levels Associated with Giardiasis and Dietary Zinc Intake in Mice

The association of giardiasis with the malabsorption of zinc remains controversial. This study investigated changes in serum zinc levels in Giardia-infected mice subjected to different dietary zinc regimens. Thirty-five mice (strain C₃H/H_eJ) were randomly categorized into two groups. The first group was inoculated with 5 × 10⁶ Giardia trophozoites (n = 18), and the second group remained Giardia free (n = 17). Each group (Giardia infected and Giardia free) was randomly classified into three subgroups and given low (9 mg Zn/kg), normal (33 mg Zn/kg), and high levels (288 mg Zn/kg) of dietary zinc over a 2-week period for acclimation. Fourteen days post-Giardia infection, all of the mice were euthanized and blood samples were collected. The number of trophozoites was quantified (hematocytometer), and serum zinc levels were determined via atomic absorption spectrophotometry. Significant increases in the median weights were only found in the Giardia-free mice (p < 0.05). A higher final median weight was found in the Giardia-free group when compared with that of the Giardia-infected group given low dietary zinc (p = 0.013). In the Giardia-infected group with low dietary zinc, the geometric mean of trophozoites was 3,498 ± 101 (SE) per milliliter. The Giardia-infected group had lower serum zinc levels than did the Giardia-free group with the high dietary zinc regimens (p < 0.05). Our results are consistent with studies among human populations, but further studies are required to elucidate the actual mechanism governing the zinc–giardiasis interaction.     

Defensive Role of Quercetin Against Imbalances of Calcium,Sodium, and Potassium in Galactosemic Cataract

Galactosemic cataracts are characterized by electrolyte disturbances resulting in osmotic imbalance and loss of transparency. We have studied the defensive role of quercetin, a bioflavonoid, against the alterations of calcium (Ca²⁺), sodium (Na⁺), and potassium (K⁺) concentrations in galactose-induced cataract in a rodent model. The experimental study was conducted on weanling male Wistar rats with an average body weight of 34 ± 0.9 g. Different groups received normal stock AIN 93 diet (group A, n = 8), AIN 93 diet with 30% galactose (group B, n = 8), and AIN 93 diet with 30% galactose + quercetin at 400 mg/100 g diet (group C, n = 8). Aldose reductase activity and protein content and concentrations of Ca²⁺, Na+, and K⁺ were determined in normal and cataractous lenses. Treatment with quercetin resulted in a significant decrease in Na⁺ and Ca²⁺ and aldose reductase levels and an increase in K⁺ and protein levels in galactosemic cataractous lenses. These results imply that inclusion of quercetin contributes to lens transparency through the maintenance of characteristic osmotic ion equilibrium and protein levels of the lens.     

Oral Iron Treatment Has a Positive Effect on Iron Metabolism in Elite Soccer Players

The purpose of this study was to assess the effects of oral iron supplementation on hematological and iron metabolism in elite soccer players. Thirty-five members of the Real Zaragoza SAD soccer team took part in this study: group A (GA, n = 24; Spanish Premier League) took an oral iron supplement of 80 mg day⁻¹ for 3 weeks, and group B (GB, n = 11; Spanish Third Division League) did not receive any supplementation. In GA, the parameters were measured before and after giving the iron supplements, while in GB, measurements were only made at the time of collecting the second set of data from GA. After supplementation, GA showed an increase in serum iron (SI) (P < 0.05), serum ferritin (Ftn) (P < 0.01), and transferrin saturation (Sat) (P < 0.01) with respect to the basal values. In addition, GA showed higher values of hematocrit (P < 0.01), mean corpuscular volume (P < 0.01), Ftn (P < 0.01), and Sat (P < 0.01) than GB. No significant differences were found in any other parameters. More specifically, a higher percentage of players had Ftn levels above upper limits in GA vs. GB (P < 0.05), and GB had a higher incidence of Ftn below lower limits with respect to subjects in GA (P < 0.01). Further, after treatment, 58.3% of GA had >800 mg of SI, while all players in GB presented levels below the lower limits. In conclusion, iron supplementation with 80 mg·day⁻¹ for 3 weeks, before the start of the soccer season, can be recommended for elite soccer players.     

Role of a Tetraethylammonium-Sensitive Component of Potassium Currents in High-Frequency Tonic Impulsation Generated by Rat Retinal Ganglion Cells

Using the voltage/current clamp technique in the whole-cell configuration, we studied the role of the highly tetraethylammonium (TEA) -sensitive component of integral potassium current in the generation of high-frequency tonic impulsation by rat retinal ganglion cells (RGCs). Application of 0.5 mM TEA led to a decrease in the frequency of evoked tonic impulsation by RGCs by 63% (from 55 ± 10 sec^–1 in the control to 26 ± 5 sec^–1 in the presence of the blocker; n = 11). In this case, the duration of single action potentials at the level of 50% their amplitude increased by 64% (from 1.1 ± 0.1 to 1.8 ± 0.1 msec; n = 11), the rate of repolarization decreased by 54% (from −101 ± 9 to −46 ± 5 mV/msec; n = 11), and the amplitude of afterhyperpolarization dropped by 62% (from −16 ± 2 to −6 ± 2 mV; n = 11). Upon the action of 0.5 mM TEA, the amplitude of the integral potassium current in RGCs decreased; the current component sensitive to the above blocker was equal to 0.41 ± 0.05 nA (n = 6), while the respective value in the control was 1.62 ± 0.14 nA (n = 12). Thus, a moderate (on average, by 25%) decrease in the amplitude of the above potassium current significantly influenced the characteristics of impulse activity generated by RGCs. The TEA-sensitive component of the current was similar to the Kv3.1/Kv3.2 potassium current described earlier. The obtained data are indicative of the key role of the highly TEA-sensitive component of the potassium current (passed probably via Kv3.1/Kv3 channels) in high-frequency tonic activity generated by RGCs.     

Muscle damage induced by running training during recovery from hindlimb suspension: the effect of dantrolene sodium

We examined the extent of morphological alterations and the myosin heavy chain (MHC) distribution in the rat soleus muscle after a 4-week period of spontaneous recovery or retraining after hindlimb suspension (HS). Moreover, we tested the hypothesis that dantrolene sodium, which affects the flux of calcium over the sarcoplasmic reticulum membrane, was able to attenuate muscle damage. Three groups of rats were submitted to 3 weeks of HS, followed by either 4 weeks of unrestricted cage activity (HC, n = 7), or running training for the same period and were compared to age-matched animals (C, n = 8). Trained rats were treated with either placebo or dantrolene sodium (HTP, HTD, n = 8 each, respectively). Four weeks after HS recovery, the percentage of myofibres with internal nuclei (%in) was determined by histological staining with hematoxylin and eosin. %in was affected by the individual rat (P < 0.001), and was higher in the mid-belly region of the muscle (P < 0.05). Muscle damage, as estimated by %in, was more extensive in trained rats (i.e. HTP and HTD) than in HC animals (23% and 12%, respectively). Moreover, dantrolene sodium tended to exert a protective effect on training-induced muscle injury. A 12% increase in type I MHC was observed in both HTP and HTD rats, in comparison with group C animals (P < 0.001). The relative proportion of type-I MHC was inversely correlated with %in (r = −0.65, P < 0.001). Running recovery led to an increased citrate synthase activity in comparison with that of C or HC rats. In conclusion, the present findings demonstrate that running recovery from HS increases the incidence of muscle damage, and that dantrolene sodium administration has only limited protective effects against exercise-induced muscle injury. Accepted: 29 April 1997     

Advanced glycation end products and antioxidant status in nondiabetic and streptozotocin induced diabetic rats: effects of copper treatment

The effects of Cu(II) supplementation on glycemic parameters, advanced glycation end products (AGEs), antioxidant status (glutathione; GSH and total antioxidant capacity; TAOC) and lipid peroxidative damage (thiobarbituric acid-reactive substances, TBARS) were investigated in streptozotocin (STZ) induced diabetic rats. The study was carried out on Wistar albino rats grouped as control (n = 10), CuCl₂ treated (n = 9), STZ (n = 10) and STZ,CuCl₂ treated (n = 9). STZ was administered intraperitoneally at a single dose of 65 mg/kg and CuCl₂, 4 mg copper/kg, subcutaneously, every 2 days for 60 days. At the end of this period, glucose(mg/dl), Cu(μg/dl), TBARS(μmol/l), TAOC(mmol/l) were measured in plasma, GSH(mg/gHb) in erythrocytes and glycated hemoglobin (GHb)(%) in blood. Plasma AGE-peptides(%) were measured by HPLC flow system with spectrofluorimetric and spectrophotometric detectors connected on-line. Data were analyzed by the non-parametric Kruskal–Wallis and Mann–Whitney U test. In the STZ group glucose, GHb and AGE-peptide levels were all significantly higher than the control group (P < 0.01, P < 0.05, and P < 0.01, respectively). CuCl₂ treated group had significantly lower glucose but significantly higher GHb, TAOC and TBARS levels than the control group (P < 0.05, P < 0.001, P < 0.05 and P < 0.001, respectively). STZ,CuCl₂ treated group had significantly higher GHb, TAOC and TBARS levels compared with the control group (P < 0.001, P < 0.05 and P < 0.05, respectively); but only TAOC level was significantly higher than the STZ group (P < 0.01). This experimental study provides evidence that copper intake increases total antioxidant capacity in both nondiabetic and diabetic states. However despite the potentiated antioxidant defence, lipid peroxidation and glycation enhancing effects of CuCl₂ are evident under nondiabetic conditions.     

Copper and Zinc in the Serum,Urine, and Hair of Patients with Wilson’s Disease Treated with Penicillamine and Zinc

The purpose of this study was to determine the different levels of copper and zinc in the serum, urine, and scalp hair of patients with Wilson’s disease receiving different, currently accepted methods of treatment to reduce the copper load (penicillamine—group 1, n = 8; zinc—group 2, n = 8; penicillamine+zinc—group 3, n = 8). Blood, urine, and hair samples were collected from the patients. All three treatments resulted in a significant decrease of the serum copper levels. Significantly increased levels of zinc in the serum were detected in the patients in groups 2 and 3 (19.1 and 18.8 μmol/l, respectively; p < 0.05). Copper excretion in the urine significantly increased during its administration to groups 1 and 3 (11.5 and 7.94 μmol/24 h respectively; p < 0.001) due to the effect of penicillamine. The administration of zinc as monotherapy (group 2) or in combination with penicillamine (group 3) led to an increase of its excretion (25.3 and 22.4 μmol/24 h, respectively; p < 0.01). Only an insignificant rise of the copper content in the hair was found in all three groups of patients. The content of zinc in the hair did not differ significantly in any of the groups in comparison with the control group.     

Effects of diode laser therapy on the acellular dermal matrix

Acellular dermal matrix (ADM) was subcutaneously implanted into calvarian skin of male Wistar rats (n = 40). Low-level laser (λ 685 nm, 4 J/cm²) was locally applied in experimental group (n = 20) above the skin flap. Grafts were harvested at 1, 3, 7 and 14 days after surgery and underwent histological analyses. In treated animals, the extent of edema and the number of inflammatory cells were reduced (P < 0.05). The amount of collagen in graft treated with low-level laser were significantly higher than those of controls (P < 0.05) and were statistically more prominent on the 14th day after surgery. The mean count of fibroblasts was significantly higher in the low-laser therapy group within the 3rd day, showing a marked influx of fibroblasts into area. In conclusion, wound healing of the ADM appear to be positively affected by laser therapy.