فهرست مطالب

Iranian Biomedical Journal
Volume:6 Issue: 2, Jul-Apr 2002

  • 93 صفحه،
  • تاریخ انتشار: 1381/02/01
  • تعداد عناوین: 8
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  • Shahrokhi, Anis Jafari, V. Bakayev, Reinhold Schirmbeck, Jorg. Reimann, Saeid Bouzari Page 47

    Hepatitis B surface antigen is the first genetically engineered vaccine licensed for human use. Various strategies have been proposed to obtain a vaccine that would bypass the need for injection. In this study, a non-toxic portion of heat-stable enterotoxin of Escherichia coli that is capable of adhering to epithelial cells was inserted at amino acid position 112 of hepatitis surface antigen. The construct was used for transfection of human embryonic kidney cells in order to assess the expression of the hybrid protein. The data obtained showed a very low level of expression. In vivo antibody production and cytotoxic T lymphocyte response in B6 mice were assessed using DNA immunization. Three out of five injected mice responded with titers >10 mIU/ml anti-HBsAg and cytotoxic T-lymphocyte response was much higher with construct encoding the chimeric protein. Although this study proves that the chimeric protein is capable of eliciting both humoral and cellular responses, but further work is required to fully explore the feasibility of combining the properties of the two proteins.

  • Dariush Minai, Tehrani. Ezzatollah Keyhani, Zahra Sobhani, Damavandifar Page 55
    The effect of Triton X-100, Na cholate and Tween 80 on the solubilization of integral membrane proteins in intact cells, spheroplasts and inner-membrane fragments of Salmonella typhimurium was studied. The detergents were used in various concentrations (1.6 to 64 mM) and cytochromes b and d were used as marker to monitor the solubilization of membrane-bound proteins. Results showed that no inner-membrane protein solubilization was detected after the treatment of intact cells with detergents. The effect of Na cholate and Tween 80 on spheroplasts and inner-membrane fragments was also negligible in comparison to Triton X-100. Triton X-100 solubilized cytochromes from inner-membrane fragments more efficiently than from spheroplasts. The ratio of total protein solubilization to solubilize cytochromes showed that in spheroplasts this ratio was maximum at 1.6 mM Triton X-100 while it was maximum at 16-32 mM Triton X-100 in inner-membrane fragments. This difference between spheroplasts and inner-membrane fragments may be due to the orientation of the inner- membrane in spheroplasts (right side out) and inner-membrane fragments (in-side out as well as right side out), and to the presence of peripheral proteins attached to cytoplasmic membrane in spheroplasts.
  • Ali Babaei. Taghi Ghafghazi, Mohsen Ani Page 63
    There are many reports for involvement of ATP-sensitive potassium channels in pancreatic, cardiac and vascular smooth muscle cells. This study examined the effect of single doses of K+ channel openers; diazoxide, minoxidil and K+ channel blockers; chlorpropamide, glibenclamide on serum concentration of aldosterone in male rats. Blood samples were obtained 60 minutes after drug treatment and serum aldosterone level was determined by RIA. The basal serum aldosterone was 659.32 ± 71.48 pg/ml and after diazoxide or minoxidil administration increased to 1188.53 ± 99.45 pg/ml and 1392.69 ± 177.83 pg/ml, respectively. Chlorpropamide or glibenclamide treatment did not produce any change in basal serum aldosterone concentration, but in early streptozotocin-induced diabetic rats decreased serum aldosterone level significantly (P<0.001). Pretreatment with glibenclamide blocked aldosterone response to diazoxide but did not affect aldosterone response to exogenous ACTH to the same extent. Effect of diazoxide in insulin-treated rats was approximately similar to that of normal rats. Comparison of blood glucose concentration determined in normal, insulin treated and diabetic rats after different drug administration showed that there is no correlation between blood glucose level and the responses observed in serum hormone concentration. The results indicate that regulatory processes involved in the secretion of aldosterone are responsive to drugs affecting glibenclamide–sensitive K+ channels
  • Saeed Mirdamadi, Hajar Sadeghi, Nora Sharafi, Masous D. Fallahpour, Farzaneh Aziz Mohseni, Mohammad Reza Bakhtiari Page 69

    Many organisms produce lactic acid by fermentation, but most industrially important strains are from the genus Lactobacillus and Rhizopus oryzae. L(+)-Lactic acid is the only optical isomer for use in pharmaceutical and food industries because human body is only adapted to assimilate this form. In this research, six strains of Lactobacillus and four strains of R. oryzae (known as high producer) were examined for optical isomers of lactic acid. The production of lactic acid was improved and lactic acid produced in submerged media on rotary shaker incubator. The optical isomers of lactic acid were examined by L(+) and D(-) lactate dehydrogenase kit. All the R. oryzae strains tested produced only L(+) isomer of lactic acid. The highest fungal and bacterial producer strains were R. oryzae PTCC 5263, Lactobacillus plantarum PTCC 1058, L. Bulgaricus PTCC 1332 and L. delbruekii subsp delbruekii PTCC 1333. Lactobacilli strains produced combination of both optical isomers of lactic acid. Among them, L. casei subsp. Casei produced the low amount of D(-)-lactic acid (2%). The optimum concentration of glucose for lactic acid production by R. oryzae and Lactobacillus strains were 180 g/l and 80–120 g/l, respectively.

  • Mehdi Nematbakhsh, Parichehr Hayat, Davoodi. Pavin Rajabi, Seyyed Hossein Samarian Page 77

    Estrogen Replacement Therapy (ERT) in postmenopausal women may decrease the risk of Coronary Artery Diseases (CAD). We hypothesized that Nitric Oxide (NO) releasing due to ERT may be the essential factor by which endothelial permeability decreases. Four groups of ovariectomized rabbits were under investigation for five weeks. Groups 1 & 4 received high cholesterol diet and other two groups (2 & 3) had normal diet. Estradiol valerate (5 mg) was injected weekly in groups 1 & 2. Blood samples were taken before and after the experiment. Finally, the animals were sacrificed for endothelial permeability determination and pathological investigation of aortae. After five weeks, the total cholesterol, triglycerides, HDL and LDL were significantly different between high cholesterol‑fed and normal diet groups (P<0.05). In cholesterol-fed groups, triglycerides concentration was also different significantly (P<0.05). Nitrite concentration was increased significantly in group 1, and it was different from other groups (P<0.05). A considerable decrease of aorta permeability was obtained in group 1 but it was not significantly different from group 4 (P<0.1). The considerable existence of fatty streaks was observed in the animals aortae of group 4, and it was significantly different from group 1 (P<0.05). It suggests that prevention of intimal collection of foam cells and fatty streak in aorta by estrogen may be exerted by NO production. Iran. Biomed.

  • Soheila Ajdary. Latif Hamidpoor, Tahereh Zandiedh Page 83
    In chronic myelogenous leukemia (CML), the mature granulocytes originate from a stem cell line harboring an abnormal chromosome, therefore it is possible that metabolic-functional abnormalities occur in the morphologically mature cells. In the present study, the phagocytic activity including intracellular killing, nitro blue tetrazolium (NBT) reduction, and phagocytosis were studied in 37 CML patients in different stages of the disease. The results were compared with those of 37 normal controls. Patients’ neutrophils display significantly lower intracellular killing (P<0.01), NBT reduction (P<0.01) and phagocytosis (P<0.001) than that of normal controls. Analysis of the results revealed an inverse correlation between phagocytic activity and leukocyte count or percentage of immature cells (r = -0.3, P<0.01). In conclusion, the results indicate that neutrophils of CML patients have impaired phagocytic activity. This defect is more prominent in patients in blastic phase, whereas patients in remission show normal values.
  • Mehri Ghafourian Boroujerdnia, Rahim Chinipardaz Page 89
    Spontaneous abortion is the most common complication of pregnancy. Several lines of evidence indicate that immunologic effector cells may play a role in the pathogenesis of idiopathic repetitive abortions. Leukocytes form a substantial proportion of stromal cells in decidua and the endometrial granulated lymphocytes (eGL) is the predominant decidual leukocyte population in the first trimester of normal human pregnancy. To investigate the involvement of eGL population in repetitive abortion of unknown etiology, a comparative analysis was performed on first-trimester decidual tissues obtained from thirty patients with recurrent spontaneous abortion and thirty samples at therapeutic abortion. The eGL in paraffin-embedded sections of all samples were demonstrated with phloxine-tartrazine staining. The results showed the presence of many eGL that scattered individually throughout the stroma and formed some aggregates around glands and some vessels. The number of positive cells was increased in the recurrent aborted decidua compared with normal pregnancy decidua, but the difference was not significant (p>0.05).
  • Sedigheh Javadpour, Dariush Norouzian, Azim Akbarzadeh, Saeed Mirdamadi, Ehrokh Farahmand Page 93

    Penicillin acylase (EC 3.5.1.11) has been a target of study for a long time because of its pivotal role in the deacylation of the penicillin into the 6- aminopenicillanic acid (6-APA) and the side-chain organic acids. This property of penicillin acylase has been exploited commercially for large scale production of 6-APA, which is the key intermediate in the manufacture of semi-synthetic penicillins. Due to the worldwide demand for semi-synthetic penicillins, production of 6-APA has been increased up to 7000 tons in recent years. In this study, Sixty-five strains of E. coli were investigated for penicillin acylase activity using fluorescamine method. The 6-aminopenicillanic acid formed in the reaction mixture was developed on thin layer chromatography. One-minute beta-lactamase test was carried out to follow any trace of penicillinase activity. Only one sample designated as E.coli PPA78 was found to be penicillin acylase producer. The optimal pH and temperature of penicillin acylase activity of the whole cells were determined to be 8.0 and 57°C, respectively. Km value and activation energy of the enzymatic hydrolysis reaction of penicillin G by intracellular enzyme were estimated as 0.004 mmol and 6.2 Kcal/mol, respectively.

    Keywords: penicillin acylase, E. coli, Fluorescamine