Cutaneous lesions sensory impairment recovery and nerve regeneration in leprosy patients

It is important to understand the mechanisms that enable peripheral neurons to regenerate after nerve injury in order to identify methods of improving this regeneration. Therefore, we studied nerve regeneration and sensory impairment recovery in the cutaneous lesions of leprosy patients (LPs) before and after treatment with multidrug therapy (MDT). The skin lesion sensory test results were compared to the histopathological and immunohistochemical protein gene product (PGP) 9.5 and the p75 nerve growth factor receptors (NGFr) findings. The cutaneous neural occupation ratio (CNOR) was evaluated for both neural markers. Thermal and pain sensations were the most frequently affected functions at the first visit and the most frequently recovered functions after MDT. The presence of a high cutaneous nerve damage index did not prevent the recovery of any type of sensory function. The CNOR was calculated for each biopsy, according to the presence of PGP and NGFr-immunostained fibres and it was not significantly different before or after the MDT. We observed a variable influence of MDT in the recovery from sensory impairment in the cutaneous lesions of LPs. Nociception and cold thermosensation were the most recovered sensations. The recovery of sensation in the skin lesions appeared to be associated with subsiding inflammation rather than with the regenerative activity of nerve fibres.

Handgrip strength and physical activity in frail elderly

Abstract OBJECTIVE To investigate the association between handgrip strength (HS) and physical activity in physical frailty elderly. METHOD Cross-sectional quantitative study with a sample of 203 elderly calculated based on the population estimated proportion. Tests were applied to detect cognitive impairment and assessment of physical frailty. Descriptive statistics and multivariate analysis by binary logistic regression were used, and also Student's t-test and Fisher's exact test. RESULTS A total of 99 (64.3%) elderly showed decreased handgrip strength and 90 (58.4%) elderly presented decrease in physical activity levels. There was a statistically significant difference between these two components (p=0.019), in which elderly who have decreased HS have lower levels of physical activity. For low levels of physical activity and decreased HS, there was no evidence of significant difference in the probability of the classification as frail elderly (p<0.001). CONCLUSION The components handgrip strength and physical activity are associated with the frail elderly. The joint presence of low levels of physical activity and decreased handgrip strength leads to a significantly higher probability of the elderly to be categorized as frailty.

Compressive neuropathy of the first branch of the lateral plantar nerve: a study by magnetic resonance imaging

Abstract Objective: To assess the prevalence of isolated findings of abnormalities leading to entrapment of the lateral plantar nerve and respective branches in patients complaining of chronic heel pain, whose magnetic resonance imaging exams have showed complete selective fatty atrophy of the abductor digiti quinti muscle. Materials and Methods: Retrospective, analytical, and cross-sectional study. The authors selected magnetic resonance imaging of hindfoot of 90 patients with grade IV abductor digiti quinti muscle atrophy according to Goutallier and Bernageau classification. Patients presenting with minor degrees of fatty muscle degeneration (below grade IV) and those who had been operated on for nerve decompression were excluded. Results: A female prevalence (78.8%) was observed, and a strong correlation was found between fatty muscle atrophy and plantar fasciitis in 21.2%, and ankle varices, in 16.8% of the patients. Conclusion: Fatty atrophy of the abductor digiti quinti muscle is strongly associated with neuropathic alterations of the first branch of the lateral plantar nerve. The present study showed a significant association between plantar fasciitis and ankle varices with grade IV atrophy of the abductor digiti quinti muscle.

Topographic anatomical study of the sciatic nerve relationship to the posterior portal in hip arthroscopy

Objective: To evaluate the anatomic topographic relation between the sciatic nerve in relation to the piriform muscle and the posterior portal for the establishment of hip arthroscopy.Methods: We dissected 40 hips of 20 corpses of adult Brazilians, 17 male and three female, six black, six brown and eight white. We studied the anatomical relationship between the sciatic nerve and the piriform muscle with their variations and the distance between the lateral edge of the sciatic nerve and the posterior portal used in hip arthroscopy. We then classified the anatomical alterations found in the path of the sciatic nerve on the piriform muscle.Results: Seventeen corpses had bilateral relationship between the sciatic nerve and the piriform muscle, i.e., type A. We found the following anatomical variations: 12.5% of variant type B; and an average distance between the sciatic nerve and the portal for arthroscopy of 2.98cm. One body had type B anatomical variation on the left hip and type A on the right.Conclusion: the making of the posterior arthroscopic portal to the hip joint must be done with careful marking of the trochanter massive; should there be difficult to find it, a small surgical access is recommended. The access point to the portal should not exceed two centimeters towards the posterior superior aspect of the greater trochanter, and must be made with the limb in internal rotation of 15 degrees.

Serotonergic neurons in the caudal raphe nuclei discharge in association with activity of masticatory muscles

There is a dense serotonergic projection from nucleus raphe pallidus and nucleus raphe obscurus to the trigeminal motor nucleus and serotonin exerts a strong facilitatory action on the trigeminal motoneurons. Some serotonergic neurons in these caudal raphe nuclei increase their discharge during feeding. The objective of the present study was to investigate the possibility that the activity of these serotonergic neurons is related to activity of masticatory muscles. Cats were implanted with microelectrodes and gross electrodes. Caudal raphe single neuron activity, electrocorticographic activity, and splenius, digastric and masseter electromyographic activities were recorded during active behaviors (feeding and grooming), during quiet waking and during sleep. Seven presumed serotonergic neurons were identified. These neurons showed a long duration action potential (>2.0 ms), and discharged slowly (2-7 Hz) and very regularly (interspike interval coefficient of variation <0.3) during quiet waking. The activity of these neurons decreased remarkably during fast wave sleep (78-100%). Six of these neurons showed tonic changes in their activity positively related to digastric and/or masseter muscle activity but not to splenius muscle activity during waking. These data are consistent with the hypothesis that serotonergic neurons in the caudal raphe nuclei play an important role in the control of jaw movements

Modification of pyruvate kinase and lactate dehydrogenase in foot muscle of the sea mussel Mytilus galloprovincialis under anaerobiosis and recovery

The modification of pyruvate kinase (PK) and lactate dehydrogenase (LDH) activity in foot muscle of the mussel Mytilus galloprovincialis during exposure to air and recovery in water was investigated. In the course of exposure to air, the activity of these enzymes measured at high and low substrate concentrations showed successive increases and decreases. Returning the mussels to water after exposure to air affected enzyme activity in a manner similar to anaerobiosis. When measuring at saturated concentrations of substrates and substrate and coenzyme for PK and LDH, respectively, the maximum activation of PK (37%) was observed at 4 h of animal exposure to air, and for LDH (67%) at 6 h exposure to air. During 24 h of exposure of animals to air, PK activity practically reached the stock level, while LDH was still activated (148%). The change in lactate dehydrogenase activity in mussel muscle during anoxia and recovery is described here for the first time. Variation in pyruvate kinase activity during exposure to air and recovery is linked to the alteration of half-maximal saturation constants and maximal velocity for both substrates. The possible role of reversible phosphorylation in the regulation of pyruvate kinase and lactate dehydrogenase properties is discussed

Morphometry and acetylcholinesterase activity of the myenteric plexus of the wild mouse Calomys callosus

The myenteric plexus of the digestive tract of the wild mouse Calomys callosus was examined using a histochemical method that selectively stains nerve cells, and the acetylcholinesterase (AChE) histochemical technique in whole-mount preparations. Neuronal density was 1,500 ± 116 neurons/cm2 (mean ± SEM) in the esophagus, 8,900 ± 1,518 in the stomach, 9,000 ± 711 in the jejunum and 13,100 ± 2,089 in the colon. The difference in neuronal density between the esophagus and other regions was statistically significant. The neuron profile area ranged from 45 to 1,100 µm2. The difference in nerve cell size between the jejunum and other regions was statistically significant. AChE-positive nerve fibers were distributed within the myenteric plexus which is formed by a primary meshwork of large nerve bundles and a secondary meshwork of finer nerve bundles. Most of the nerve cells displayed AChE activity in the cytoplasm of different reaction intensities. These results are important in order to understand the changes occurring in the myenteric plexus in experimental Chagas' disease

Increased angiotensin-converting enzyme activity in the left ventricle after infarction

An increase in angiotensin-converting enzyme (ACE) activity has been observed in the heart after myocardial infarction (MI). Since most studies have been conducted in chronically infarcted individuals exhibiting variable degrees of heart failure, the present study was designed to determine ACE activity in an earlier phase of MI, before heart failure development. MI was produced in 3-month old male Wistar rats by ligation of the anterior branches of the left coronary artery, control rats underwent sham surgery and the animals were studied 7 or 15 days later. Hemodynamic data obtained for the anesthetized animals showed normal values of arterial blood pressure and of end-diastolic pressure in the right and left ventricular cavities of MI rats. Right and left ventricular (RV, LV) muscle and scar tissue homogenates were prepared to determine ACE activity in vitro by measuring the velocity of His-Leu release from the synthetic substrate Hyp-His-Leu. ACE activity was corrected to the tissue wet weight and is reported as nmol His-Leu g-1 min-1. No significant change in ACE activity in the RV homogenates was demonstrable. A small nonsignificant increase of ACE activity (11 &plusmn; 9%; P0.05) was observed 7 days after MI in the surviving left ventricular muscle. Two weeks after surgery, however, ACE activity was 46 &plusmn; 11% (P<0.05) higher in infarcted rats compared to sham-operated rats. The highest ACE activity was demonstrable in the scar tissue homogenate. In rats studied two weeks after surgery, ACE activity in the LV muscle increased from 105 &plusmn; 7 nmol His-Leu g-1 min-1 in control hearts to 153 &plusmn; 11 nmol His-Leu g-1 min-1 (P<0.05) in the remaining LV muscle of MI rats and to 1051 &plusmn; 208 nmol His-Leu g-1 min-1 (P<0.001) in the fibrous scar. These data indicate that ACE activity increased in the heart after infarction before heart failure was demonstrable by hemodynamic measurements. Since the blood vessels of the scar drain to the remaining LV myocardium, the high ACE activity present in the fibrous scar may increase the angiotensin II concentration and decrease bradykinin in the cardiac tissues surrounding the infarcted area. The increased angiotensin II in the fibrous scar may contribute to the reactive fibrosis and hypertrophy in the left ventricular muscle surviving infarction

Effects of piperitenone oxide on the intestinal smooth muscle of the guinea pig

We investigated the effects of piperitenone oxide (PO), a major constituent of the essential oil of Mentha x villosa, on the guinea pig ileum. PO (30 to 740 µg/ml) relaxed basal tonus without significantly altering the resting membrane potential. In addition, PO relaxed preparations precontracted with either 60 mM K+ or 5 mM tetraethylammonium in a concentration-dependent manner. At concentrations from 0.1 to 10 µg/ml PO potentiated acetylcholine-induced contractions, while higher concentrations (>30 µg/ml) blocked this response. These higher PO concentrations also inhibited contractions induced by 60 mM K+. PO also blocked the components of acetylcholine contraction which are not sensitive to nifedipine or to solutions with nominal zero Ca2+ and EGTA. These results show that PO is a relaxant of intestinal smooth muscle and suggest that this activity may be mediated at least in part by an intracellular effect

Chronic imipramine treatment-induced changes in acetylcholinesterase (EC 3.1.1.7) activity in discrete rat brain regions

Cholinergic as well as monoaminergic neurotransmission seems to be involved in the etiology of affective disorders. Chronic treatment with imipramine, a classical antidepressant drug, induces adaptive changes in monoaminergic neurotransmission. In order to identify possible changes in cholinergic neurotransmission we measured total, membrane-bound and soluble acetylcholinesterase (Achase) activity in several rat brain regions after chronic imipramine treatment. Changes in Achase activity would indicate alterations in acetylcholine (Ach) availability to bind to its receptors in the synaptic cleft. Male rats were treated with imipramine (20 mg/kg, ip) for 21 days, once a day. Twenty-four hours after the last dose the rats were sacrificed and homogenates from several brain regions were prepared. Membrane-bound Achase activity (nmol thiocholine formed min-1 mg protein-1) after chronic imipramine treatment was significantly decreased in the hippocampus (control = 188.8 ± 19.4, imipramine = 154.4 ± 7.5, P<0.005) and striatum (control = 850.9 ± 59.6, imipramine = 742.5 ± 34.7, P<0.005). A small increase in total Achase activity was observed in the medulla oblongata and pons. No changes in enzyme activity were detected in the thalamus or total cerebral cortex. Since the levels of Achase seem to be enhanced through the interaction between Ach and its receptors, a decrease in Achase activity may indicate decreased Ach release by the nerve endings. Therefore, our data indicate that cholinergic neurotransmission is decreased after chronic imipramine treatment which is consistent with the idea of an interaction between monoaminergic and cholinergic neurotransmission in the antidepressant effect of imipramine

Increase in skeletal muscle protein content by the ß-2 selective adrenergic agonist clenbuterol exacerbates hypoalbuminemia in rats fed a low-protein diet

This investigation examined how the nutritional status of rats fed a low-protein diet was affected when the animals were treated with the ß-2 selective agonist clenbuterol (CL). Males (4 weeks old) from an inbred, specific-pathogen-free strain of hooded rats maintained at the Dunn Nutritional Laboratory were used in the experiments (N = 6 rats per group). CL treatment (Ventipulmin, Boehringer-Ingelheim Ltd., 3.2 mg/kg diet for 2 weeks) caused an exacerbation of the symptoms associated with protein deficiency in rats. Plasma albumin concentrations, already low in rats fed a low-protein diet (group A), were further reduced in CL rats (A = 25.05 ± 0.31 vs CL = 23.64 ± 0.30 g/l, P<0.05). Total liver protein decreased below the level seen in either pair-fed animals (group P) or animals with free access to the low-protein diet (A = 736.56 ± 26 vs CL = 535.41 ± 54 mg, P<0.05), whereas gastrocnemius muscle protein was higher than the values normally described for control (C) animals (C = 210.88 ± 3.2 vs CL = 227.14 ± 1.7 mg/g, P<0.05). Clenbuterol-treated rats also showed a reduction in growth when compared to P rats (P = 3.2 ± 1.1 vs CL = -10.2 ± 1.9 g, P<0.05). This was associated with a marked decrease in fat stores (P = 5.35 ± 0.81 vs CL = 2.02 ± 0.16 g, P<0.05). Brown adipose tissue (BAT) cytochrome oxidase activity, although slightly lower than in P rats (P = 469.96 ± 16.20 vs CL = 414.48 ± 11.32 U/BAT x kg body weight, P<0.05), was still much higher than in control rats (C = 159.55 ± 11.54 vs CL = 414.48 ± 11.32 U/BAT x kg body weight, P<0.05). The present findings support the hypothesis that an increased muscle protein content due to clenbuterol stimulation worsened amino acid availability to the liver and further reduced albumin synthesis causing exacerbation of hypoalbuminemia in rats fed a low-protein diet.

Effect of hypoxia on the activity and binding of glycolytic and associated enzymes in sea scorpion tissues

The effect of hypoxia on the levels of glycogen, glucose and lactate as well as the activities and binding of glycolytic and associated enzymes to subcellular structures was studied in brain, liver and white muscle of the teleost fish, Scorpaena porcus. Hypoxia exposure decreased glucose levels in liver from 2.53 to 1.70 µmol/g wet weight and in muscle led to its increase from 3.64 to 25.1 µmol/g wet weight. Maximal activities of several enzymes in brain were increased by hypoxia: hexokinase by 23%, phosphoglucoisomerase by 47% and phosphofructokinase (PFK) by 56%. However, activities of other enzymes in brain as well as enzymes in liver and white muscle were largely unchanged or decreased during experimental hypoxia. Glycolytic enzymes in all three tissues were partitioned between soluble and particulate-bound forms. In several cases, the percentage of bound enzymes was reduced during hypoxia; bound aldolase in brain was reduced from 36.4 to 30.3% whereas glucose-6-phosphate dehydrogenase fell from 55.7 to 28.7% bound. In muscle PFK was reduced from 57.4 to 41.7% bound. Oppositely, the proportion of bound aldolase and triosephosphate isomerase increased in hypoxic muscle. Phosphoglucomutase did not appear to occur in a bound form in liver and bound phosphoglucomutase disappeared in muscle during hypoxia exposure. Anoxia exposure also led to the disappearance of bound fructose-1,6-bisphosphatase in liver, whereas a bound fraction of this enzyme appeared in white muscle of anoxic animals. The possible function of reversible binding of glycolytic enzymes to subcellular structures as a regulatory mechanism of carbohydrate metabolism is discussed.

The insulin receptor substrate 1 associates with phosphotyrosine phosphatase SHPTP2 in liver and muscle of rats

Insulin stimulates the tyrosine kinase activity of its receptor resulting in the phosphorylation of its cytosolic substrate, insulin receptor substrate-1 (IRS-1) which, in turn, associates with proteins containing SH2 domains. It has been shown that IRS-1 associates with the tyrosine phosphatase SHPTP2 in cell cultures. While the effect of the IRS-1/SHPTP2 association on insulin signal transduction is not completely known, this association may dephosphorylate IRS-1 and may play a critical role in the mitogenic actions of insulin. However, there is no physiological demonstration of this pathway of insulin action in animal tissues. In the present study we investigated the ability of insulin to induce association between IRS-1 and SHPTP2 in liver and muscle of intact rats, by co-immunoprecipitation with anti-IRS-1 antibody and anti-SHPTP2 antibody. In both tissues there was an increase in IRS-1 association with SHPTP2 after insulin stimulation. This association occurred when IRS-1 had the highest level of tyrosine phosphorylation and the decrease in this association was more rapid than the decrease in IRS-1 phosphorylation levels. The data provide evidence against the participation of SHPTP2 in IRS-1 dephosphorylation in rat tissues, and suggest that the insulin signal transduction pathway in rat tissues is related mainly to the mitogenic effects of the hormone.

Use of fluorescent probes to follow membrane traffic in nerve terminals

Optical tracers in conjunction with fluorescence microscopy have become widely used to follow the movement of synaptic vesicles in nerve terminals. The present review discusses the use of these optical methods to understand the regulation of exocytosis and endocytosis of synaptic vesicles. The maintenance of neurotransmission depends on the constant recycling of synaptic vesicles and important insights have been gained by visualization of vesicles with the vital dye FM1-43. A number of questions related to the control of recycling of synaptic vesicles by prolonged stimulation and the role of calcium to control membrane internalization are now being addressed. It is expected that optical monitoring of presynaptic activity coupled to appropriate genetic models will contribute to the understanding of membrane traffic in synaptic terminals.

Evaluation of electromyographic activity and heart rate responses to isometric exercise. The role played by muscular mass and type

The purpose of the present study was to examine the relationship between the electromyographic (EMG) activity and heart rate (HR) responses induced by isometric exercise performed by knee extension (KE) and flexion (KF) in men. Fifteen healthy male subjects, 21 ± 1.3 years (mean ± SD), were submitted to KE and KF isometric exercise tests at 100% of maximal voluntary contraction (MVC). The exercises were performed with one leg (right or left) and with two legs simultaneously, for 10 s in the sitting position with the hip and knee flexed at 90o. EMG activity (root mean square values) and HR (beats/min) were recorded simultaneously both at rest and throughout the sustained contraction. The HR responses to isometric exercise in KE and KF were similar when performed with one and two legs. However, the HR increase was always significantly higher in KE than KF (P<0.05), whereas the EMG activity was higher in KE than in KF (P<0.05), regardless of the muscle mass (one or two legs) involved in the effort. The correlation coefficients between HR response and the EMG activity during KE (r = 0.33, P>0.05) and KF (r = 0.15, P>0.05) contractions were not significant. These results suggest that the predominant mechanism responsible for the larger increase in HR response to KE as compared to KF in our study could be dependent on qualitative and quantitative differences in the fiber type composition found in each muscle group. This mechanism seems to demand a higher activation of motor units with a corresponding increase in central command to the cardiovascular centers that modulate HR control.