Showing 5 results for Concentration
Jabal Amely F, Malek Zadeh F,
Volume 61, Issue 1 (4-2003)
Abstract
In Vivo, after administration of treatment, concentrations of antimicrobial agents will reduce to sub-inhibitory levels (sub-MIC) and may therefore affect the properties of target bacteria. The purpose of the present study was to investigate the in vitro effect of sub-minimum inhibitory concentrations (sub-MIC) of ampicillin, gentamicin and nalidixin acid on morphology, growth, ammonium production and urease activity of proteus mirabilis. Proteus mirabilis is well recognized as an important urinary tract pathogen.
Materials and Methods: Several of its properties have been studied in relation to pathogenesis manifested in urinary tract such as urease activity.
Results: In the presence of ampicillin, long filamenteous cells was produced and the length of the cells was increased at the higher concentration of ampicillin. Sub-MIC of ampicillin and gentamicin affected the growth pattern and prolonged the lag-phase of growth. This affected was significant when gentamicin was used. Nalidixic
acid of 1/2 MIC greatly reduced the growth rate, while the lag phase was not
changed. In the presence of sub-MICs of ampicillin and gentamicin, the amount of
ammonium production increased. In medium with 1/2 MIC of ampicillin, the
ammonium production was 30 times of control, while the urease specific activity of sonicated cells did not show any significant changes.
Conclusion: It seemed that the antibiotics enhanced the cell membrane permeability for substrate and enzyme. Nalidixic acid didn't show any significant effect on ammonia production, and urease specific activity of proteus mirabilis. The results indicate that the sub-MIC of antibiotics can effect virulence factors of proteus mirabilis.
Hashemi Sj, Zaini F, Daie R, Zibafar E, Zakeri Ma,
Volume 69, Issue 2 (5-2011)
Abstract
Background: Different studies have shown that despite the expanding number of antifungal agents, death rate caused by Aspergillus species has been increased during the recent decades due to drug-resistance occurrence, increased minimum inhibitory concentration (MIC) and cross-resistance among the isolated species. Regarding the lack of effective response to conventional treatments and antifungal susceptibility patterns of the most common isolated Aspergillus species, this study was undertaken to draw a clearer picture in the Iranian setting.
Methods: During 13 months from September 2009 to October 2010, 50 clinically isolated Aspergillus cases were identified based on the method described by Klich (2002) and their morphological features. Subsequently, their susceptibility test was carried out according to NCCLS- M38A broth microdilution method.
Results: We found that 7.5% of the isolated A. flavus with an MIC>2 µg/ml to amphotericin B were probably clinically resistant types, and 25% of them with an
MIC<8 µg/ml to itraconazole were less sensitive isolated species. The isolates were less
sensitive to voriconazole too. The MIC range of 9 strains of A. niger and the MIC of one strain of A. fumigatus had increased to all the three medications in comparison with similar foreign studies.
Conclusion: In this study we found that the MICs of most isolates were in the range of the reference strains and the MICs of some isolates were in the range of similar foreign studies. In some significant cases, the MICs were beyond the known ranges showing the lower sensitivity of Iranian isolates and their increased MIC patterns.
Shabani Zanjani M, Ebrahimi N,
Volume 69, Issue 5 (8-2011)
Abstract
Background: Entanglement of the umbilical cord around fetal neck has been reported to be associated with birth asphyxia. On the other hand, current evidence suggests that umbilical arterial pH analysis provides the most sensitive reflection of birth asphyxia. In this study we aimed to evaluate and compare the umbilical arterial hydrogen-ion concentration (pH) and to analyze the blood gases of neonates with or without nuchal cord.
Methods: In this cohort study, 92 newborns with and 95 without nuchal cords were enrolled at Shahid Akbar Abadi Hospital in Tehran, Iran between the years 2009 and 2010. From each newborn an umbilical arterial blood sample was collected to measure pH, base excess and blood gases.
Results: There were no statistically significant differences between newborns with or without nuchal cord regarding maternal age, gestational age, and history of pregnancy. The mean pH in the newborns with nuchal cord (7.21±0.1) was significantly less than the value in the newborns without the cord (7.28±0.1), (P<0.001). In contrast, the mean base excess in the newborns with nuchal cord was more than the ones without the cord (P<0.001). Seven newborns (7.9%) in the group with nuchal cord passed meconium during labor while only one (1%) newborn did so in the other group.
Conclusion: Our finding showed that nuchal cord had a significant relationship with acidosis in newborns with nuchal cord. However, this finding needs further investigation to reach a common conclusion.
Aalami S, Nikoui V, Irani M, Bakhtiarian A,
Volume 70, Issue 7 (10-2012)
Abstract
Background: There are conflicting reports about zinc, a trace element, in the pathogenesis of hypertension and other cardiovascular diseases. The aim of this study was to evaluate the role of zinc in high blood pressure.
Methods: We conducted this study on 80 patients with primary (idiopathic) hypertension and 80 normotensive people with similar age who attended to Tehran Heart Center between 2007 and 2008. We examined the effect of zinc concentration on blood pressure in both sexes in four age groups (41-50, 51-60, 61-70 and 71-80 years old). We measured plasma zinc concentration by atomic absorption.
Results: The mean plasma zinc concentrations were 0.456±0.04 µg/ml and 0.551±0.055 µg/ml in patients with hypertension and in normotensive people, respectively, (P≤0.05). Nevertheless, the mean plasma zinc concentrations were 0.494 µg/ml and 0.486 µg/ml in men with and without hypertension, respectively. The mean plasma zinc concentrations of women with and without hypertension, respectively were 0.415 µg/ml and 0.596 µg/ml, showing a significant difference between two groups (P≤0.001). Moreover, there was a significant difference in plasma zinc concentration between hypertensive and normotensive people in 51 to 60 years age group (P≤0.05), but difference were not significant between other age groups.
Conclusion: The results of this study revealed the relationship between the decrease in plasma zinc concentration and increase in blood pressure in women and in the men aged 51 to 60 years.
Mohammadreza Aflatoonian , Mehrdad Khatami , Iraj Sharifi , Shahram Pourseyedi , Mansour Khatami , Hajar Yaghobi , Mahin Naderifar ,
Volume 75, Issue 8 (11-2017)
Abstract
Background: Nanoparticles are particles that have at least one dimension between 1 and 100 nanometers. Nanoparticles are a new generation of antimicrobial agents. Nanoparticles with antimicrobial activity, especially as a new class of biomedical materials for use in increasing the level of public health in daily life have emerged. Zinc oxide nanoparticles have attracted a great attention due to the variety of their applications in medical science. The aim of this study was to evaluate and compare the antimicrobial activity of zinc oxide nanoparticles synthesized by green method.
Methods: This experimental study was done in 2017, from March to September in the Bam Research Center of University of Medical Sciences Kerman, Iran. Green synthesis of zinc oxide nanoparticles was investigated using cumin seeds. The physicochemical characteristics of synthesized nanoparticles were studied by UV-visible ultraviolet spectrometer (Analytik Jena AG, Germany), X-ray diffraction and transmission electron microscope (TEM) (Carl Zeiss, Germany). Broth microdilution method was used to investigate the antimicrobial activity of zinc oxide nanoparticles. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of these nanoparticles were determined for Pseudomonas aerogenes and Enterococcus faecalis strains.
Results: The UV-visible ultraviolet spectroscopy showed an absorption peak in the range of 370 nm. Transmission electron microscopy shows the synthesis of zinc oxide nanoparticles, mostly spherical, with a size less than 50 nm. Minimum inhibitory concentration of zinc oxide nanoparticles against P. aerogenes and E. faecalis strains was determined at 6.25 and 12.5 μg/ml, respectively. Both bacteria were sensitive to zinc oxide nanoparticles. This sensitivity was higher for gram-negative bacteria.
Conclusion: Zinc oxide nanoparticles were produced using Iranian natural resources and our results showed significant antibacterial activity. Nanotechnology creates materials with novel properties every day, and creates new hope for improving environmental pollution. These nanoparticles can be used as a new generation of antimicrobial agents in various medical disciplines. For example, toothpaste containing zinc nanoparticles can be produced and prescribed for patients with immune deficiency to prevent the growth of microbial pathogens in the mouth and its transmission to the patient's body.
