Determining Changes in Electromyography Indices when Measuring Maximum Acceptable Weight of Lift in Iranian Male Students.

BACKGROUND: In spite of the increasing degree of automation in industry, manual material handling (MMH) is still performed in many occupational settings. The aim of the current study was to determine the maximum acceptable weight of lift using psychophysical and electromyography indices. METHODS: This experimental study was conducted among 15 male students recruited from Tehran University of Medical Sciences. Each participant performed 18 different lifting tasks which involved three lifting frequencies, three lifting heights and two box sizes. Each set of experiments was conducted during the 20 min work period using free-style lifting technique and subjective as well as objective assessment methodologies. SPSS version 18 software was used for descriptive and analytical analyses by Friedman, Wilcoxon and Spearman correlation techniques. RESULTS: The results demonstrated that muscle activity increased with increasing frequency, height of lift and box size (P<0.05). Meanwhile, MAWLs obtained in this study are lower than those in Snook table (P<0.05). In this study, the level of muscle activity in percent MVC in relation to the erector spine muscles in L3 and T9 regions as well as left and right abdominal external oblique muscles were at 38.89%, 27.78%, 11.11% and 5.55% in terms of muscle activity is more than 70% MVC, respectively. The results of Wilcoxon test revealed that for both small and large boxes under all conditions, significant differences were detected between the beginning and end of the test values for MPF of erector spine in L3 and T9 regions, and left and right abdominal external oblique muscles (P<0.05). The results of Spearman correlation test showed that there was a significant relation between the MAWL, RMS and MPF of the muscles in all test conditions (P<0.05). CONCLUSION: Based on the results of this study, it was concluded if muscle activity is more than 70% of MVC, the values of Snook tables should be revisited. Furthermore, the biomechanical perspective should receive special attention in determining the standards for MMH.

Experimental hyperlipidemia induces insulin resistance in sheep.

This study aimed to evaluate the effects of intravenous infusion of a soybean-based lipid emulsion on some blood energy-related metabolites and insulin sensitivity indexes in sheep. Four clinically healthy ewes were assigned into a 2-treatment, 2-period cross-over design. Either normal saline (NS) or lipid emulsion (LE) was intravenously introduced at a rate of 0.025 mL·kg(-1) min(-1) for 6 h. The concentrations of blood nonesterified fatty acid (NEFA), beta-hydroxybutyrate, triglyceride, cholesterol, urea, creatinine, cortisol, glucose, and insulin were measured at different time points. After 6 h, intravenous glucose tolerance test was performed. Lipid infusion elicited an increase (P < 0.05) in the NEFA, beta-hydroxybutyrate, and triglyceride concentrations compared with the baseline value and NS infusion. Infusion of NS did not influence blood glucose concentration; however, LE infusion increased plasma glucose concentration (P < 0.05). At time point 12 h, serum insulin concentrations were increased (P < 0.05) in NS treatment; however, such an increase was not observed in the LE treatment. Insulin sensitivity index for the LE infusion was lower (P < 0.05) than that for the NS treatment. The glucose effectiveness was not (P > 0.05) different among treatments. In the LE treatment, acute-phase insulin responses increased (P < 0.05) and disposition index decreased (P < 0.001) compared with NS treatment. The results showed that experimentally induced NEFA in blood could cause insulin resistance in sheep. The current model could be used to evaluate the pathogenesis of conditions associated with increased lipid mobilization and insulin resistance.

Changes in blood profile in sheep receiving raw garlic, garlic oil or monensin.

This study aimed to evaluate the effects of supplementing a basal diet (CTR) with raw garlic (GAR) or garlic oil (GAO) on blood profile in sheep. Monensin (MON, 33 mg/kg DM) was used as positive control. Four ruminally fistulated rams were used in three experiments each arranged in a 4 × 4 Latin square design with 28-day periods. Experiments 1 and 2 differed in the dose of GAR (75 vs. 100 g/kg DM) and GAO (500 vs. 750 mg/kg DM), while experiment 3 was designed to compare the two doses of each additive (GAR and GAO). The animals were fed a basal diet as TMR consisting of 77.83% forage (alfalfa hay and corn silage) and 22.17% concentrate, providing 10.50 MJ/kg DM (metabolizable energy) and 16.5% crude protein to cover maintenance energy and protein requirements. Supplementation of monensin decreased (P < 0.05) ß-hydroxybutyrate (BHB) and non-esterified fatty acid (NEFA) concentrations in the blood compared with other treatments. There was no significant effect of additives on serum concentration of glucose, total triglycerides, cholesterol, total protein, albumin and blood urea nitrogen (BUN). Although the serum insulin concentration was elevated in sheep receiving MON and GAO (P < 0.01), no change was observed in blood glucose concentration. No significant effect of GAO and GAR was observed in key energy and protein-related blood metabolites. However, administration of monensin had a positive influence on energy indices. In conclusion, whereas parameters characterizing the energy balance did not show a significant effect of GAR supplementation, a higher insulin concentration in GAO-treated animals was observed.

Mechanisms of muscular electrophysiological and mitochondrial dysfunction following exposure to malathion, an organophosphorus pesticide.

Muscle dysfunction in acute organophosphorus (OP) poisoning is a cause of death in human. The present study was conducted to identify the mechanism of action of OP in terms of muscle mitochondrial dysfunction. Electromyography (EMG) was conducted on rats exposed to the acute oral dose of malathion (400 mg/kg) that could inhibit acetylcholinesterase activity up to 70%. The function of mitochondrial respiratory chain and the rate of production of reactive oxygen species (ROS) from intact mitochondria were measured. The bioenergetic pathways were studied by measurement of adenosine triphosphate (ATP), lactate, and glycogen. To identify mitochondrial-dependent apoptotic pathways, the messenger RNA (mRNA) expression of bax and bcl-2, protein expression of caspase-9, mitochondrial cytochrome c release, and DNA damage were measured. The EMG confirmed muscle weakness. The reduction in activity of mitochondrial complexes and muscular glycogen with an elevation of lactate was in association with impairment of cellular respiration. The reduction in mitochondrial proapoptotic stimuli is indicative of autophagic process inducing cytoprotective effects in the early stage of stress. Downregulation of apoptotic signaling may be due to reduction in ATP and ROS, and genotoxic potential of malathion. The maintenance of mitochondrial integrity by means of artificial electron donors and increasing exogenous ATP might prevent toxicity of OPs.

Evaluation of the level of house dust mite allergens, Der p 1 and Der f 1 in Iranian homes, a nationwide study

Background: Exposure to house dust mites (HDMs) is a major risk factor for the development of allergic symptoms. HDMs are worldwide in distribution. Assessing these allergens in each area is a critical step in evaluating the risk of sensitisation and controlling allergic symptoms. The aim of the present study was to evaluate the level of major HDMs, Der p 1 and Der f 1, in various parts of Iran. Methods: In 2009, 257 dust samples were obtained from living rooms’ carpets in seven cities throughout Iran with different geoclimatic conditions. The level of Der p 1 and Der f 1 was measured by commercial ELISA. Results: Detectable level of Der p 1 and Der f 1 levels were only found in Gorgan and Sari, two cities near the Caspian Sea with moderate temperatures and high relative humidity. In both of these cities, Der f 1 was more frequent than Der p 1 (100% vs. 85%) and was found to be at a higher level than Der p 1 (geometric mean 3128 vs. 439 ng/g dust, P < 0.001). Conclusion: The results of this study confirm that house dust mites in Iran are restricted to the Caspian Sea coastal areas, and in other parts, due to seasonal variations of temperature and humidity mites are not able to grow well and therefore are not an important risk factor for sensitisation and respiratory allergies (AU)

Evaluation of the level of house dust mite allergens, Der p 1 and Der f 1 in Iranian homes, a nationwide study.

BACKGROUND: Exposure to house dust mites (HDMs) is a major risk factor for the development of allergic symptoms. HDMs are worldwide in distribution. Assessing these allergens in each area is a critical step in evaluating the risk of sensitisation and controlling allergic symptoms. The aim of the present study was to evaluate the level of major HDMs, Der p 1 and Der f 1, in various parts of Iran. METHODS: In 2009, 257 dust samples were obtained from living rooms' carpets in seven cities throughout Iran with different geoclimatic conditions. The level of Der p 1 and Der f 1 was measured by commercial ELISA. RESULTS: Detectable level of Der p 1 and Der f 1 levels were only found in Gorgan and Sari, two cities near the Caspian Sea with moderate temperatures and high relative humidity. In both of these cities, Der f 1 was more frequent than Der p 1 (100% vs. 85%) and was found to be at a higher level than Der p 1 (geometric mean 3128 vs. 439ng/g dust, P<0.001). CONCLUSION: The results of this study confirm that house dust mites in Iran are restricted to the Caspian Sea coastal areas, and in other parts, due to seasonal variations of temperature and humidity mites are not able to grow well and therefore are not an important risk factor for sensitisation and respiratory allergies.

Hair Contamination of Sheepdog and Pet Dogs with Toxocara canis Eggs.

BACKGROUND: We tried to investigate the hair contamination of pet dogs and farm sheepdog with Toxocara eggs in terms of the different sex and age groups in north-west of Iran (Urmia and its suburbs). METHODS: Hair samples were collected from a total of 138 pet and farm sheepdogs from November 2008 to June 2009 in Urmia City and the suburb (West Azerbaijan-Iran) and examined for the presence of T. canis eggs. RESULTS: T. canis eggs found in 60 samples altogether (pet and shepherd dogs) showed a contamination rate of 36.2%. The number of observed T. canis eggs in each microscope field was varied from 1 to > 400. The age of the dog was found a significant factor to influence the prevalence and intensity of contamination, with 82% of all the eggs recovered from puppies (six months and younger). Additionally, the numbers of eggs in farm sheepdogs were significantly higher than pet dogs (P<0.05). CONCLUSION: This report shows that direct contact with T. canis infected dogs, particularly puppies from shepherd dogs, may pose a serious hazard to human. Besides, as they may harbor a considerable number of eggs on their hair, they can contaminate the soil and the environment.

Synergistic antibacterial activity of the essential oil of Cuminum cyminum L. seed and nisin in a food model.

AIMS: To investigate effects of various concentrations of the essential oil of Cuminum cyminum L. seed alone and in combination with nisin on survival of vegetative forms of Bacillus cereus and Bacillus subtilis in a food model (commercial barley soup) and their ultrastructure. METHODS AND RESULTS: Gas chromatography-mass spectrometry analysis indicated that cumin aldehyde (29·02%) and α-terpinen-7-al (20·70%) constituted the highest amount of the essential oil. The lowest concentration of the essential oil significantly affected the growth of the bacteria at 8°C but not at 25°C. Synergistic effect of the essential oil in combination with the lowest concentration of nisin was observed on the bacteria at 8°C. Evaluation of the sensory properties showed that concentration of 0·15 µl ml−1 of the essential oil was the most acceptable. CONCLUSIONS: The essential oil of C. cyminum L. seed showed the most bactericidal effects on B. cereus at 8°C. Ultrastructural studies of vegetative cells confirmed the synergistic destructive effects of the essential oil and nisin on membrane and cell wall of the bacteria.

Modulation of the ipsilateral and contralateral H reflexes following ipsilateral mechanical pressure of the foot in normal subjects.

OBJECTIVE: Mechanoreceptors from the foot sole likely contribute in the reflex regulations. Therefore, it was hypothesized that repetitive low threshold afferents stimulation would have an inhibitory effect on the soleus H-reflexes. METHODS: Sixteen normal subjects voluntarily, participated in the study and were randomly allocated. Subjects were remained in prone position. The Cutaneous Mechanical Pressure (CMP equal to 50% of leg and foot weight) was applied to the ipsilateral lateral and Medial plantar surface by a designed instrument through a square plate (30 x 30 mm). H reflex as an indicator for excitability of motoneurones was bilaterally elicited before and after the application of the CMP. The H-reflex parameters were estimated. RESULTS: Mechanical pressure significantly depressed soleus H-reflex excitability in ipsilateral and contralateral feet in all subjects. CONCLUSION: The demonstration of a decrease in H-reflex excitability as a result of applied pressure to the foot sole suggests that the change in reflex excitability is the result of a common spinal mechanism. The results highlight the modulatory effects that natural stimulation of afferents can have on reflex excitability. SIGNIFICANCE: The placement of a small flat plate, in order to apply pressure to the plantar eminence, may be useful for modulation of muscle tone. In addition, these findings might be useful for reducing spasticity; because spasticity is at least partially caused by hyperexcitability of the motorneuron pool.

Functional assessment of knee joint position sense following anterior cruciate ligament reconstruction.

CONTEXT: The anterior cruciate ligament (ACL) has both mechanical and proprioceptive (sensory) functions. Knee-joint proprioception has been assessed using either reproduction of position or threshold to detect passive motion in non-weight-bearing positions. It has been suggested that a more functional and dynamic/active assessment of proprioception might clarify the effects of injury and reconstruction on the proprioceptive function of ACL at the knee joint. OBJECTIVE: To assess knee joint position sense (JPS) following ACL reconstruction in functional positions. SUBJECTS: Twelve male patients who had undergone ACL reconstruction and 12 male healthy control subjects participated in the study. METHODS AND MAIN OUTCOME MEASURES: JPS was evaluated by reproduction of the angles in weight-bearing position with limb movement into flexion and extension. The dominant knee of healthy subjects and both (reconstructed and uninjured) knees of the patients were tested. Absolute angular error was used as a dependent variable. RESULTS: There was no significant difference between the operated and uninjured knees of patients or between patients and healthy controls (p>or=0.05). These results were measured during two tasks of limb movement into flexion and extension. CONCLUSION: We found no evidence of impaired JPS in weight-bearing positions in subjects with ACL reconstruction at a mean follow-up of 11 months after surgery compared with subjects with healthy knees.

Plasma biochemistry of one-humped camel (Camelus dromedarius): effects of anticoagulants and comparison with serum.

The effects of various types of anticoagulants on plasma biochemistry were studied in man and various animals but limited informations are existing for camel plasma biochemistry. Eleven clinically healthy one-humped camels were blood sampled in different tubes containing different anticoagulants and plain tubes for harvesting plasma and serum. The concentrations of glucose, cholesterol, triglyceride, total bilirubin, urea, creatinine, total protein, albumin, calcium, inorganic phosphorus, magnesium, and chloride and the activity of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatine kinase (CK) and gamma glutamyl transferase (GGT) were measured. Except for the amounts of AST, ALT, CK, total bilirubin, and inorganic phosphorus, other measured parameters were significantly lower in citrated plasma than in serum. Most parameters did not show any difference, but significant increase for CK activity and significant decrease for GGT, cholesterol, creatinine and chloride were seen when heparin was used as anticoagulant. Using EDTA as an anticoagulant caused a significant difference in the amounts of some measured parameters in plasma except glucose, AST, ALT, GGT, cholesterol, albumin, total protein, bilirubin, and triglyceride in comparison with serum.

A comparative study of whole body vibration training and conventional training on knee proprioception and postural stability after anterior cruciate ligament reconstruction.

OBJECTIVE: To compare the effect of a whole body vibration training (WBVT) programme with a conventional training (CT) programme on knee proprioception and postural stability after anterior cruciate ligament (ACL) reconstruction. METHODS: Twenty athletes with unilateral ACL reconstruction were randomly assigned to the WBVT or CT group; all participants received 12 sessions of WBVT or conventional training. Absolute error in joint repositioning for two target angles (30 degrees and 60 degrees ) was measured with the Biodex dynamometer; bilateral dynamic postural stability (anteroposterior, mediolateral and overall stability indices) was measured with the Biodex Stability System pre-intervention and post-intervention. RESULTS: The improvement in postural stability in the WBVT group was significantly greater than that in the CT group (p< or =0.05). The p values of the changing scores of open overall, open anteroposterior, open mediolateral, closed overall, closed anteroposterior and closed mediolateral stability indices were 0.002, 0.010, 0.0001, 0.001, 0.0001 and 0.046, respectively. In addition, there were significant differences in all averages of absolute angular error at 60 degrees and 30 degrees between the WBVT and CT groups in both knees (p = 0.001 in healthy knees and p = 0.001 and p = 0.0001 in reconstructed knees), apart from the healthy knees at the 30 degrees target position, which was not significant (p = 0.131). CONCLUSIONS: Whole body vibration training improved proprioception and balance in athletes with reconstructed ACL.

Is there any relationship between the Modified Ashworth Scale scores and alpha motoneuron excitability indicators?

The purpose of this study was to investigate the relationship between the modified Ashworth scale (MAS) scores and alpha motoneuron excitability indicators. Thirty-one post-stroke patients were assessed for this object. The main outcome measures were the MAS and electro physiologic assessments. The latter was performed using both conventional (Hmax/Mmax) and new (Hslope/Mslope) measures of spinal excitability. Data on thirty-one adult subjects with hemiplegia (twenty-five men and six women) were analysed. The soleus Hmax/Mmax ratio appeared to correlate directly with the MAS scores (r = 0.36; P < 0.05). Correlation between the MAS scores and either Hslope/Mslope ratio or H-reflex latency was not significant (P > 0.05). In seventeen patients whose H-reflex could be evoked bilaterally, spinal excitability indicators showed significant difference between the affected and non-affected sides (P < 0.05). Based on the results of this study, there is no relationship between the MAS scores and the preferred measure of alpha motoneuron excitability. This research suggests that the MAS could not distinguish between the reflexive and non-reflexive components of the hypertonicity in ankle plantar flexors.

The effect of transcutaneous electrical nerve stimulation on sympathetic skin response.

The aim of present study was to determine whether combination of transcutaneous electrical nerve stimulation (TENS) and acupuncture inhibits sympathetic nerve activity in healthy humans. Multiunit efferent postganglionic sympathetic activity was recorded with Toennies set. In this study, the aim was to obtain latency, amplitude and duration of sympathetic skin response (SSR) and skin temperature (ST) from both hands in 15 healthy subjects. Subjects randomly assigned and everybody participated in all the three groups [Control Group (CG), Acupuncture Group (AG) and Nerve Stimulation Group (NSG)]. TENS (2 Hz, 250 microsecond) was applied over the median nerve of the right elbow in NSG for 20 min, either, TENS was applied over (HE-7) point of the right hand in CG (TENS off) and AG (TENS on) for 20 min. SSR (lat, amp, dur) and ST data was recorded before TENS and for immediate, 5 min and 10 min post--TENS. ST was recorded in distal phalanx of index finger of both hands and SSR was recorded from both hands. TENS in CG did not affect ST and SSR following stimulation. TENS applied at AG and NSG caused a significant increase in ST (P = 0.001), significant increase in latency of SSR (P = 0.001), significant decrease in amplitude of SSR (P = 0.001) and no significant changes were observed in duration of SSR (P > 0.05). Then statistical analysis showed differences between both of groups (AG & NSG) for ST and SSR post--TENS. Transcutaneous electrical nerve stimulation inhibits sympathetic nerve activity in healthy humans.

Reasons for delay in the management of patients with pulmonary tuberculosis.

The study assessed reasons for delay between patient's first symptoms of tuberculosis and initiation of therapy. Fifty newly diagnosed cases of pulmonary tuberculosis admitted to the NRITLD in Teheran were studied. Mean patient delay before consulting a physician was 12.5 +/- 10 days, significantly higher among men than women. Mean delay until the physicians' diagnosis was 93 +/- 80 days, significantly higher for women than for men. Almost no treatment delay was observed (mean 4 +/- 4 days after diagnosis had been confirmed). The major delay was the time taken by physicians to diagnose tuberculosis in symptomatic patients. An active and effective national tuberculosis programme is needed in the Islamic Republic of Iran, with integration of the programme in medical school curricula and in continuing professional training.

Reasons for delay in the management of patients with pulmonary tuberculosis

The study assessed reasons for delay between patient's first symptoms of tuberculosis and initiation of therapy. Fifty newly diagnosed cases of pulmonary tuberculosis admitted to the NRITLD in Teheran were studied. Mean patient delay before consulting a physician was 12.5 +/- 10 days, significantly higher among men than women. Mean delay until the physicians' diagnosis was 93 +/- 80 days, significantly higher for women than for men. Almost no treatment delay was observed [mean 4 +/- 4 days after diagnosis had been confirmed]. The major delay was the time taken by physicians to diagnose tuberculosis in symptomatic patients. An active and effective national tuberculosis programme is needed in the Islamic Republic of Iran, with integration of the programme in medical school curricula and in continuing professional training

Field potentials generated by group II muscle afferents in the lower-lumbar segments of the feline spinal cord.

The actions of group II muscle afferents projecting to the lower-lumbar (L6 and L7) segments of the cat spinal cord were investigated by recording the cord dorsum and focal synaptic field potentials evoked by electrical stimulation of hindlimb muscle nerves. Cord dorsum potentials recorded over the lower-lumbar segments were generally much smaller than those produced by group II afferents terminating within the midlumbar and sacral segments. Only group II afferents of tibialis posterior produced potentials with an amplitude (mean maximal amplitude 39 microV, n = 7) approaching that of potentials over other segments. Focal synaptic potentials (mean maximal amplitudes 135-200 microV) were evoked by group II afferents of the following muscle nerves, listed in order of effectiveness: quadriceps, tibialis posterior (throughout L6 and L7), gastrocnemius soleus, flexor digitorum longus, posterior biceps-semitendinosus and popliteus (mainly within L7). Field potentials were recorded in the dorsal horn (laminae IV-V) and also more ventrally in a region which included the lateral part of the intermediate zone (lateral to the large group I intermediate field potentials) and often extended into the ventral horn (laminae V-VII). The latencies of the group II potentials are considered compatible with the monosynaptic actions of the fastest conducting group II muscle afferents. The results are compared with morphological evidence on the pattern of termination of group II muscle afferents in the lower-lumbar segments and with previous descriptions of the actions of group II muscle afferents in midlumbar and sacral segments.

Interneurones in pathways from group II muscle afferents in the lower-lumbar segments of the feline spinal cord.

Interneurones receiving excitatory input from group II muscle afferents of hindlimb nerves and located in the lower-lumbar (L6-L7) segments of the cat spinal cord were investigated using both extracellular and intracellular recording. The interneurones were located mainly in the lateral parts of laminae IV-VII, dorsal and lateral to the main region in which interneurones with input from group I muscle afferents are located. Almost half the sample of interneurones (38 of 76) were characterized by an ipsilateral ascending projection within the lateral funiculus to the L4 level. The most powerful group II excitation was produced by afferents of the quadriceps and deep peroneal muscle nerves (which discharged 70-80% of extracellularly recorded neurones) while group II afferents of tibialis posterior, posterior biceps-semitendinosus and gastrocnemius soleus were also highly effective (discharging 45-55% of extracellularly recorded neurones). A proportion of intracellularly recorded group II EPSPs were monosynaptic. Seventy-five per cent of the extracellularly recorded interneurones were discharged by group II afferents of two or more muscle nerves and 43% by afferents of three or more nerves. Group I muscle afferents evoked small EPSPs in over one-quarter of the intracellularly recorded interneurones and virtually all were strongly excited by cutaneous afferents. Evidence of excitatory input from joint, interosseous and group III muscle afferents was also observed. The properties of the interneurones are compared with those of others in the lumbosacral segments and the possibility that they may function as last-order premotor interneurones is discussed.

Topographical organization of group II afferent input in the rat spinal cord.

The organization of neurons in the lumbar enlargement of the rat spinal cord processing information conveyed by group II afferents of hind-limb muscle nerves has been investigated by using cord dorsum and intraspinal field potential recording. Group II afferents of different muscle nerves were found to evoke their strongest synaptic actions in specific segments of the lumbar cord. Group II afferents of quadriceps and deep peroneal nerves evoked potentials mainly at the rostral end of the lumbar enlargement (L1-rostral L3), whereas group II afferents of gastrocnemius-soleus and hamstring nerves evoked their main synaptic actions at the caudal end of the lumbar enlargement (L5). In the central lumbar segments (caudal L3-L4), the largest group II potentials were produced by afferents of tibialis posterior and, to a lesser degree, flexor digitorum longus. Field potentials evoked by group II afferents of quadriceps, tibialis posterior, and flexor digitorum longus were largest in the dorsal horn (up to 600 microV), but also occurred in the ventral horn where they were sometimes preceded by group I field potentials. In contrast, field potentials evoked by group II afferents of gastrocnemius-soleus and hamstring nerves were restricted to the dorsal horn. These results indicate that neurons in different segments of the rat lumbar spinal cord process information from group II afferents of different hind-limb muscles. Furthermore, the topographical organization of group II neuronal systems in the rat is similar in several respects to that in the cat and may therefore represent a general organizational feature of the mammalian spinal cord.