Background: With respect to the increased antibiotic resistance specially E.Coli and Staph aureus, and the fact that the pattern of antibiotic resistance is variable in different regions, the present study was conducted to determine the effects of different methods of mutations on the antibiotic resistance patterns and plasmids in E. Coli and Staph. Aureus. Study was performed in Mahmoudieh Azad University Laboratory.

Materials and methods: This experimental study was performed on 6 strains of Staph. Aureus and E.coli isolated from skin wound, urinary infection and fecal sources. Antibiotic resistance was performed by disk method. Having induced mutation via UV, adding antibiotic gradually, and dilution of medium, the pattern of antibiotic resistance was determined. Finally, the presence or absence of plasmid in these bacteria were detected by electrophoresis.

Results: UV and adding antibiotic gradually induce antibiotic resistance. This also disappear number of plasmid bands in E Coli. Dilution of medium cause the bacterial colonies to expand and spread in semi solid medium, however, it did not induce any alteration in antibiotic resistance.

Conclusion: UV and adding antibiotic gradually induce antibiotic resistance and disappearance of plasmid bands in E Coli rather than Staph. Aureus. This may be due to structural differences in their cells wall. With respect to the increment in antibiotic resistance during the recent years, we strongly recommend to limit the usage of some antibiotics for only critical patients.

Background: Glucose-6-phosphate dehydrogenase (G6PD) is an X-Linked enzymopathy affecting about 400 million people worldwide. Neonatal jaundice, drug induced haemolysis and infection-induced haemolysis may happen in some deficient individuals and lead to considerable mortality. The distribution of G6PD deficiency and the molecular genetics of this enzyme vary widely among different ethnic groups. The aim of this study was to find out the frequency of G6PD deficiency and characterize the molecular type of this enzyme in deficient individuals in zanjan city.

Materials and Methods: One thousand and five hundred unrelated normal male individuals were screened for G6PD deficiency by fluorescent spot test. DNA was extracted from peripheral white blood cells of the individuals who were deficient for G6PD.polymerase chain reaction (PCR) was used to amplify flanking regions of exons six and seven of this gene using a set of primers. The PCR products were digested by the enzyme Mboll and electrophoresed on 2.5% agarose gel.

Results: Thirty three out of 1500(2.2%) individuals were shown to be deficient for G6PD enzyme. Twenty four out of 33 (72.7%) showed a mutation at nt 563 of G6PD gene which is characteristic of Mediterranean type of mutation. Nine individuals (27.3%) were negative for this mutation.

Conclusion: The results of this study showed that the prevalence of G6PD deficiency was lower comparing with that of other provinces. A direct correlation has been shown between G6PD deficiency and malaria in regions in which malaria was prevalent. Since the frequency of malaria is very low in zanjan, therefore, this rate of deficiency was justifiable for this region. Despite different frequencies existing for deficiency of G6PD in central, north, northwest ant southeast regions of Iran, the results of this study and other studies carried out by us and others have shown that the prevalence for Mediterranean type of G6PD in all the above regions are approximately the same. This may indicate that the predominant G6PD mutation in Iran is of Mediterranean type and this mutation is an old mutation too.

Background: Colorectal cancer (CRC) is a common cancer througout the world. Incident rate of CRC is different depending on geographical area. The cause of CRC is multifactrial, including diet, environment and genetic. P53 gene is the most important tumor suppressor gene involved in CRC. This study was designed to detect the P53 exon 6 mutation in the colorectal cancers at Isfahan University of Medical Sciences in 2004-2005.

Materials and Methods: This study was performed on 40 colorectal patients cancer reffering to Isfahan Hospitals from 2004 to 2005. After pathological diagnosis, DNA was extracted by phenol chloroform isoamil alcohol in genetic. Exon 6 of the P53 gene was mutiplied using specific primers in a PCR assay and then the mutations were detected by gel electrophoresis and SSCP analysis.

Results: From 40 specimens, 9 (22.5%) were in the rectum and 31 (77.5%) were in the colon. 7 cases (17.5%) had P53 mutation and 33 cases (82.5%) had no mutation in exon 6.

Conclusions: According to this study exon 6 P53 gene mutation could be considered as a current exon in colorectal cancers in Isfahan.

Background: Hemophilia-A, a X-linked congenital bleeding disorder with an approximate frequency of 1 in 10000 males, is caused by a deficiency in factor VIII (FVIII). The FVIII gene is located on the long arm of the X chromosome at Xq28, spans 186 kb, and consists of 26 exons. In this research, we report a new mutation in FVIII gene in Hemophilia a patient referring to Tabriz children’s hospital in 1385.

Case Report: The patient was a 6-year old boy (HA10) referred to Tabriz children hospital in 1385 due to gum bleeding. Severe bleeding, low rate of FVIII and medical inspections showed probability of severe hemophilia A. So, to detect causal mutation, in this research we used PCR-SSCP method.

Results: A novel missense mutation in exon 4 of FVIII gene was detected that had not been reported in the list of FVIII gene mutations. The novel mutation is due to T → C transition at codon 153 (TGC) of the factor VIII gene, which replaces a cysteine with an arginine residue. This mutation was recorded in GenBank with accession number EF581382.

Conclusion: In this research it was observed that a point mutation in FVIII gene can be a cause of severe hemophilia A. So, this study shows that the methodology of PCR-SSCP may be useful in detecting most of the genetic defects of hemophilic patients. Also, disease screening and genetic consulting before marriage are necessary to inhibit the birth of affected children.

Background: Although type-2 mellitus diabetes is the most common type of diabetes, it's main cause yet to be identified. Chemokines and their receptors are probable effective systems on diabetes. CCR5 is a chemokine receptor playing an important role in immune responses. Studies showed that the known 32 mutation in CCR5 gene leads to disorder in the expression and function of this receptor. Hence, this project aimed to analyze the known 32 mutation in CCR5 chemokine receptor.

Materials and methods: Blood samples were collected from 200 type 2 diabetic patients and 300 healthy adult controls on EDTA pre-coated tubes. DNA was extracted using commercial kit. DNA samples were analyzed for 32 mutation by Gap-PCR in diabetic patients in compared to controls. The demographic information were collected through questionnaire.

Results: Our results showed that none of the diabetic patients displayed CCR5 32 mutation. While 2 out of 300 healthy controls had heterozigotic form of this mutation. Statistical analysis didn’t show any significant difference between the two groups.

Conclusion: Several different studies analyzed the relation of this mutation with different types of diseases including diabetes. All studies failed to find a relation between this mutation and type 2 diabetes. Since these studies were performed in different geographical points and races, we studied this mutation in Rafsanjanese population. Based on the results of our study it could be probably concluded that this mutation does not play a key role in the establishment of type 2 diabetes.

Background: Hearing loss is a sensorineural disorder occuring in 1 out of 500 births. It happens due to some genetic/environmental causes or both. More than 60% of cases are noninherited and 80% non syndromic with autosomal recessive inheritance. In the present study we investigated the frequency of mtDNA A1555G, A3243 and A7445G mutations among the patients in Fars province.

Materials and Methods: Seventy two non syndromic hearing loss subjects were studied. DNA was extracted using standard phenol-chloroform method. The screening of the mitochondrial gene mutations were performed using PCR-RFLP procedure. Finally, the possible mutations were confirmed by direct sequencing.

Results: None of the A1555G, A3243G and A7445G mutations was detected in this study. However, destroying a MTTL1 restriction site for the investigation of A3243G mutation, revealed a G3316A with allelic variant of 1.4% in the deaf subjects.

Conclusion: Our data indicated that the mitochondrial A1555G, A3243 and A7445G mutations have no role in auditory deficits in patients studied.

Background: Non-syndromic sensorineural hearing loss (NSHL) is the most common sensory disorder worldwide and more than 100 genetic loci have been identified in NSHL so far. Mutations in the CX26 (GJB2) gene at the DFNB1 locus on chromosome 13q12 are associated with autosomal recessive non-syndromic hearing loss in a variety of populations. The purpose of this study was to investigate the CX26 gene mutations in patients with NSHL.

Materials and Methods: In this descriptive laboratory study, 50 patients with NSHL were selected from the welfare organization of Marand city, Iran. Blood samples (5 ml) were collected from the patients and genomic DNA was extracted using the rapid genomic DNA extraction method. After amplification of the CX26 gene coding region using the polymerase chain reaction method, direct sequencing of amplified fragments was performed.

Results: In this study, six different mutations including 35delG, R184P, R216K, 363delC, C202R and V84M were identified in 10 out of 50 cases with NSHL. Therefore, mutations in the CX26 gene were found in 20% of the patients. Among these mutations, the 35delG was the most common mutation found in 5 out of 50 cases with 6% allelic frequency.

Conclusion: According to the results of this study, other genes may be involved in hearing loss in the study population and further studies are needed to identify these genes. Therefore, mutation screening of individuals with hearing loss referred to genetic counseling centers before marriage and pregnancy is recommended.