Journal of School of Public Health and

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Background and Aim: Yersinia is an important water- and food-borne bacterium causing gastroenteritis in humans.
Material and Methods: From December 2002 to July 2003, a total of 250 samples -including 158 meat samples and 92 chicken samples- were taken from butcheries and poultry shops operating under the supervision of Tehran University of Medical Sciences. We used a two-step enrichment procedure: phosphate buffer saline was used as primary enrichment within 3 weeks in refrigerator (cold enrichment). Then we applied KOH treatment as secondary enrichment and performed cultures on CIN agar.
Results: In this study, 44.4% of all samples showed Yersinia contamination. The prevalence of Yersinia was 29.1% in meat and 70.7% in poultry. Of the 155 Yersinia isolates, 53 (34.2%) were identified as Y. enterocolitica, 47(30.3%) as Y. intermedia, 42 (27%) as Y. fredriksenii and one (0,6%) as Y. kristensenii. Biotyping of Y. enterocolitica showed that 51 strains (39.7%) corresponded to biotype 1A, 13 strains (24.6%) to biotype 1B, one (1.8%) to biotype 2, three (5,7%) to biotype 3 and one (1.8%) to biotype 4. Fourteen strains (26.4%) could not be classified.
Conclusion: The high prevalence rates in meat and poultry implies that these products could be widely contaminated with Yersinia, thus serving as important vehicles for transmission to humans.

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Background and Aim: Breast cancer is an increasingly important social problem throughout the world. Rate of disease-free survival can be used to evaluate the effects of treatment and disease outcome and assess indices of disease prevention, diagnosis and treatment. With this aim in mind we made an assessment of 5-year disease-free survival in breast cancer patients.

Material and Methods: 403 breast cancer patients attending the radiotherapy-chemotherapy center at Rajaii Hospital, Babolsar were studied with regard to first-time recurrence over a period of 5 years. Data were gathered through questionnaires and statistical analysis included the Kaplan-Meier method and the Cox regression model.

Results: The median local/regional recurrence time was 15.9±5.2 months and the median systemic recurrence time was 22±14.8 months. The most common sites of recurrence were bones (46.6%), especially the lumbar vertebrae. The median disease-free survival time was 38.2±22 month. The total rate for 5-year disease-free survival was 45%. The rate ranged from 85% for stage 1 tumors to 5% for stage 4 disease. Age ≤35 years, disease stage, and lymph node involvement were found to be independent prognostic factors in time of the first recurrence of disease.

Conclusion: Comparison of our results with those from of European and  American countries showed lower rates of disease-free survival. This could be related to higher disease stage and younger age at diagnosis. These findings stress the importance of planning for earlier diagnosis and appropriate.

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Background and Aim: Type 2 diabetes mellitus is a heterogeneous disorder resulting from a combination of genetic and environmental factors which contribute to pathogenesis by influencing beta cell function and tissue insulin sensitivity. Protein tyrosine phosphatase 1B (PTP1B)" efficiently dephosphorylates the insulin receptor and attenuates insulin signaling. Recently, a 1484insG variant of the PTP1B gene was linked to increased risk of the metabolic syndrome in an Italian population, but this was not confirmed in subsequent studies. The purpose of this research was to investigate the association of 1484insG polymorphism of the PTP1B with obesity, insulin resistance, type 2 diabetes and other cardiovascular-related traits in an Iranian population.

Materials and Methods: The genotypes of 1484insG variant were determined by the PCR-RFLP method in 242 unrelated subjects, including 171 individuals with normal glucose tolerance and normal fasting glucose levels, and 71 type 2 diabetics. Insulin resistance was assessed using the homeostasis assessment model.

Results: The allelic frequency of the 1484insG polymorphism among type 2 diabetic patients and non-diabetic individuals was 6.3% and 3.8%, respectively (p=0.205). None of the subjects were homozygous for the 1484insG allele. Concerning quantitative traits in non-diabetic subjects, carriers of 1484insG allele had significantly higher body mass index (p=0.01), diastolic blood pressure (p=0.012), and HOMA-IR (p= 0.041) levels compared to those carrying the wild-type genotype. In type 2 diabetics, carriers of 1484insG allele had only significantly higher HOMA-B (P= 0/04) level compared to the individuals with the wild-type genotype.

Conclusion: Our results from a sample of Iranian type 2 diabetes cases and controls provide evidence that the 1484insG genotype of the PTP1B gene may be associated with obesity and insulin resistance.

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Background and Aim: Iron nanoparticles are broadly used in medical science, particularly in synthesis of fluorescence biomarkers, cancerous tumor therapy by hyperthermia, and as a contrast agent in MRI. Physical and chemical synthesis methods currently used to produce nanoparticles cause environmental contamination. Certain bacteria are capable of synthesizing significant amounts of iron nanoparticles, quite in conformity with the principles of green chemistry. The objective of this study was to isolate iron nanoparticle-producing magnetotactic bacteria from Arjin ore in Zanjan Province, Iran

Materials and Methods: Serial dilutions were prepared from the soil of iron ore and inoculated on a combined solid agar culture medium specifically used to isolate magnetotactic bacteria. This was followed, after incubation at 30 degree for a week, by transferring samples of colonies to special liquid culture media. After three weeks of incubation, the samples were examined by Gram staining, XRD and of scanning electron microscope (SEM).

Results: The existence of iron nanoparticles was confirmed by analysis of XRD graphs. Furthermore, scanning electron microscopy pictures proved the shape of bacteria and extracellular accumulation of iron nanoparticles produced by them.

Conclusion: Magnetotactic bacteria isolated from Arjin ore in Zanjan Province, Iran are capable of biosynthezing iron nanoparticles.