Computational simulation of applying mechanical vibration to mesenchymal stem cell for mechanical modulation toward bone tissue engineering.

Evaluation of cell response to mechanical stimuli at in vitro conditions is known as one of the important issues for modulating cell behavior. Mechanical stimuli, including mechanical vibration and oscillatory fluid flow, act as important biophysical signals for the mechanical modulation of stem cells. In the present study, mesenchymal stem cell (MSC) consists of cytoplasm, nucleus, actin, and microtubule. Also, integrin and primary cilium were considered as mechanoreceptors. In this study, the combined effect of vibration and oscillatory fluid flow on the cell and its components were investigated using numerical modeling. The results of the FEM and FSI model showed that the cell response (stress and strain values) at the frequency of 30Hz mechanical vibration has the highest value. The achieved results on shear stress caused by the fluid flow on the cell showed that the cell experiences shear stress in the range of 0.1-10Pa. Mechanoreceptors that bind separately to the cell surface, can be highly stimulated by hydrodynamic pressure and, therefore, can play a role in the mechanical modulation of MSCs at in vitro conditions. The results of this research can be effective in future studies to optimize the conditions of mechanical stimuli applied to the cell culture medium and to determine the mechanisms involved in mechanotransduction.

Taenia ovis in Small Ruminants in Iran: Prevalence, Pathology, and Economic Loss.

Taenia ovis larvae can result in economic losses in small ruminants due to condemnation of infected tissues or whole carcasses. From 2017 to 2018, the T. ovis prevalence in 16,180 sheep and 7560 goats at the Najafabad slaughterhouse in Isfahan was determined. More sheep (477; 2.9%) than goats (90; 1.2%) were found to be infected, and the prevalence was higher in animals <1 y (p < 0.0001), and higher in spring in sheep (8.2%) and goats (2.2%). Female sheep were more frequently infected than males (p < 0.0001); this did not hold true for goats. Of the tissues examined, T. ovis was found more often in the heart muscle of sheep compared with other tissues; however, infections in the heart muscle, masseter muscle, diaphragm, and triceps were similar in goats. Granulomas and caseous necrosis in the heart muscles were associated with the accumulation of mononuclear inflammatory cells and the formation of fibrous tissue around the parasite. Based solely on infected tissues found in this study, the economic loss caused by the presence of T. ovis larvae was estimated to be 4167 United States dollars (USD). Control methods, such as proper disposal of infected tissues and anthelmintic treatment of infected dogs, are necessary to decrease infection and prevent economic loss in small ruminants.

Prevalence of Linguatula serrata nymphs in slaughtered sheeps in Isfahan province, southwest of Iran.

Linguatula serrata, well known as tongue worm; is an aberrant cosmopolitan parasite, which inhabits the carnivorous mammals (especially Canidae) respiratory system. The discharged eggs infect many plant feeder animals including human that produces visceral and nasopharyngeal linguatulosis which is known as Marrara syndrome in man. In current study, the prevalence rate of infection with L. serrata nymphs in mesenteric and mediastinal lymph nodes (MLNs) of slaughtered sheeps was investigated in Esfahan Province, Iran. The MLNs of 506 slaughtered sheeps, including 236 females and 270 males, were examined for L. serrata nymphs by cutting the MLNs longitudinally and then microscopic studies for L. serrata nymphs. Sheeps were categorized into four age groups, including <1 year, 1-2 years, 2-3 years and >3 years. Results showed that 11.66 % of examined sheeps were infected with L. serrata. Age had significant effect on the prevalence rate of this parasite in sheeps (infection in sheeps with >3 years old was more than other groups significantly) and sex had no significant effect on the prevalence rate of this parasite in sheeps. Infection rate in winter was significantly lower than infection rate in spring; but there were no significant differences between the other seasons. As high prevalence rate of infection in sheeps, suggesting possibly similar high rate of infection in other animals and man in the investigated area, which this emphasizes undertaking strict control measures to reduce risk of zoonotic outbreaks. This study was demonstrated infection rate of L. serrata in sheeps in central parts of Iran.

Molecular Survey of Toxoplasma gondii in Sheep, Cattle and Meat Products in Chaharmahal va Bakhtiari Province, Southwest of Iran.

BACKGROUND: Toxoplasmosis is a worldwide spread disease. The present study examined the prevalence of Toxoplasma gondii infection among animals of edible meat (cattle and sheep) in Chaharmahal va Bakhtiari Province (Southwest of Iran) in 2012. Furthermore, we attempted for the first time to identify this parasite from the meat products in the province. METHODS: The tongue, brain, femur muscle and liver of 50 sheep and 70 cattle as well as 50 samples of meat products were selected and collected to perform molecular survey using Nested-PCR method. RESULTS: Of the studied sheep, 38% were infected. The infection rate in the age groups under 1 year, 1-2 years, and more than 2 years was 25%, 35.29% and 52.94%, respectively. The infection rate in femur muscle, brain, liver and tongue was 28%, 32%, 30% and 16%, respectively. Of the studied cattle, 8.57% were infected. The infection rate in the age groups 1-2 years, 2-4 years, and more than 4 years was 3.7%, 9.09% and 14.28%, respectively. Sheep was infected 6 times more than cattle (OR = 6.53 CI = 2.374-18.005).The infection rate among samples of meat products was 12% (6 samples out of 50 samples). CONCLUSION: Due to the high rate of this parasitic infection among the slaughtered animals as well as meat products in this region, the use of infected material can be one of the main risk factors of transmission of the parasite to humans.

Prevalence of thin-walled Sarcocystis cruzi and thick-walled Sarcocystis hirsuta or Sarcocystis hominis from cattle in Iran.

Bovine sarcocystosis is caused by Sarcocystis cruzi and is known to cause considerable morbidity and mortality in cattle. This species is distributed worldwide in cattle and is the most prevalent of the Sarcocystis species infecting cattle. There is high infection rate of sarcocyst in cattle in Iran, but to our knowledge, there is no study about identification of Sarcocystis species. This work aimed to survey prevalence of S. cruzi cyst in slaughtered cattle of Isfahan, Iran. In this study, esophageal and diaphragmatic muscles of 100 cattle were collected from Fesaran abattoir of Isfahan and examined for the presence of Sarcocystis spp. cysts macroscopically and microscopically. No macroscopic sarcocysts were found in any of the samples. In light microscopy, 89 out of 100 cattle (89%) had thin-walled cysts of S. cruzi, while 21 out of them (21%) had thick-walled sarcocysts. In addition to light microscopy, ultrastructural features of the thin-walled cyst confirmed the presence of S. cruzi.

A survey of seasonal infestation with Przhevalskiana larvae in slaughtered goats and sheep in South-Western Iran.

In this research slaughtered sheep and goats were investigated during August 2003-July 2004 at a slaughterhouse in Masjed-Soleyman, South-Western Iran. The number of infested animals with Przhevalskiana larvae and their age and sex was recorded. Collected larvae from infested animals were stored in Alcohol-Glycerin solution and were studied to determine their morphological properties and species. The data was analyzed by the chi-square test. Rate of infestation was 0.2 and 5.3% in sheep and goats, respectively. Infestation rate in male and female goats and sheep was significantly different (p<0.05). Prevalence of hypodermosis in sheep was significantly different in spring and winter, while infestation prevalence in goats was significantly different in four seasons of the year. Myiasis was seen more frequent in 2-3 and 1-2-year-old age groups of sheep and goats, respectively. The causative agents of goat and sheep hypodermosis were Przhevalskiana aegagri and Przhevalskiana crossii. The onset of fly activity was from late June to mid July.