review on taxol production through biotechnological approaches

Taxol is a very important anticancer drug which was first isolated from Yew plant [Taxus spp.]. However, Taxol supply by extraction from natural sources, has several limitations, and cannot meet current market's demands. Therefore, it seems necessary to use alternative production methods. Producing Taxol through biotechnological approaches is among the main options which have some advantages such as independency of production from geographical and environmental conditions, higher production rate, and ease of extraction. This paper contains a review on some of the most important approaches used in Taxol biotechnological production. The main body of the paper is divided into five main parts: [1] Taxol biosynthesis and related genes, [2] Factors and strategies influencing the production of Taxol by plant cell cultures of Taxus spp., [3] Strategies based on genetic manipulation of Taxus spp. for the production of Taxol, [4] Using heterologous systems in taxane production, and [5] Taxol-producing endophytes and related studies. The current status of utilizing biotechnology in producing Taxol and its future outlooks have been also described

[Cloning, gene expression analysis, and phylogenic relationship of dbat gene from Iranian endemic yew [Taxus baccata L.]]

Taxol is one of the most important anticancer agents that its supply mainly depends on biological processes. 10 - deacetyl baccatin III- 0- acetyl transferase [dbat] gene is one of the key genes in Taxol biosynthetic pathway and it is expected that overexpression of this gene would result in an increased production of taxol in biological systems. Investigation of dbat gene characteristics from Iranian endemic yew, Gene expression analysis and Construction of overexpression vector for this gene. First, sequence of the gene was cloned and then, sequence characteristics identified with Bioinformatics analysis. Gene expression analysis was performed under methyl jasmonate elicitation in several time-courses. Finally in order to construct overexpression vector, the sequence was cloned under the control of the CaMV35S promoter in to pCAMBIAI304. Comparison of sequence similarities indicated that this sequence is most similar to Taxus x hunnewelliana. There was one unique amino acid substitution and investigating substituted amino acid revealed that, this replacement can not change overall characteristics of the enzyme and thus it would result in a functional enzyme. Analysis of gene expression showed that in response to methyl jasmonate, gene expression levels increased to maximum rate up to 24 times at 12 hours after elicitation. Finally gene insertion in suitable site of overexpression vector, confirmed by digest with restriction enzymes. Elicitation of shoot cuttings of Taxus would be a suitable alternative for Taxiis cell cultures in gene expression analysis. Simplicity, feasibility, and deletion of time-consuming processes of cell culture are its main advantages

[Marginal discrepancy in two kinds of finishing line for full veneer crown prior to porcelain application [simulation method]]

One of the most important criteria for clinical acceptance and longevity of cast restorations is marginal accuracy. Marginal discrepancy causes cement layer exposure, increases risk of cement wash out leading to plaque accumulation, recurrent caries and gingival tissue inflammation. This study assessed the effect of finishing line preparation design on marginal discrepancy. In this experimental invitro study, three metal dies were prepared using simulation method with beveled shoulder, chamfer and combination of both [buccal beveled shoulder encounters palatal chamfer] that addressed groups A, B and C respectively. Seven wax patterns for each die were cast in Wiron 99 [Basemetal Alloy]. After seating the frameworks, marginal discrepancy was measured in two horizontal and vertical dimensions. The data were analyzed by one way ANOVA and Tukey multiple comparisons tests. The significant differences of horizontal marginal opening were found among three groups in buccopalatal and mesiodistal directions [P<0.003, P<0.0001]. Also, significant differences found between pair groups except to A and C in buccopalatal and A and B in mesiodistal directions. The vertical marginal opening in three groups was statistically different at mesial, distal and palatal directions [P<0.05] but not at buccal side. The vertical marginal opening differences of pair groups [A and C, B and C] at mesial, distal and palatal directions were significant [P<0.05]. Within the limitation of this study, finishing line, preparation design significantly affects the marginal discrepancy, the least and most horizontal marginal opening was produced in beveled shoulder and the combined preparation of beveled shoulder and chamfer, respectively. Chamfer preparation caused minimum vertical marginal opening while the beveled shoulder was in the next rank with no significant statistical differences

[ correlation between lateral sinus position with severity of various types of chronic otitis media]

Reduced mastoid pneumatization has been seen in most patient with chronic otitis media [COM] disease. In this study we decided to measure the distance between sigmoid sinus [SS] and posterior wall of external auditory canal[EAC]as an index of mastoid pneumatization before disease and explore the correlation between this distance and different type of COM disease. This cross-sectional study was carried out between 1381-1382 years at Shafa hospital in Kerman. The distance between SS and post wall of EAC which extracted from Schuller graphy was compared with that was measured in surgery. 51 patients with COM disease were subjected to mastoidectomy included in this study. The mean distance between SS and posterior wall of EAC in patients with type III disease [10.14 +/- 5.06 mm] was remarkably smaller than patients with type I and II of disease [15.03 +/- 6.03]. This study revealed that patients with smaller mastoid air tank are susceptible to more severe form of COM diseases

[Hemangiopericytoma: a case report]

Hemangiopericytoma is a relatively rare tumor first described in 1942, with approximately 300 cases has been described in the literature till now. In most cases it affects the trunk and lower extremities. The head and neck incidence is less than 20%, mostly in adults. We describe a rare case of malignant hemangiopericytoma in a woman located in her post neck. A60 years old female patient noted presence of a firm painless mass of 7cm diameter located in her post neck with Growing since 10 years ago and rapid enlargement during last 6 Mounts. The patient had neither history of any skeletal, sensory or motor complaints nor respiratory symptom. MRI Sequences represent non-homogenous medium signal density in T1 and homogenous high signal density in T2 Sequences After complete removal pathologic study revealed hemangiopericytoma. The patient is fine during regular follow up without any functional disability

[ correlation between helicobacter pylori infection and squamous cell carcinoma of larynx and hypopharynx]

From the most important laryngeal and hypopharyngeal cancer risk factors are smoking, alcohol and anemia. But reflux is one of the suggested etiologies. Pregnancy, Nonstroidal anti inflammation drugs and drugs decreasing the lower esophageal sphincter pressure will increase the reflux. Helicobacter pylories role in reflux formation is different due to the involved region and can also have a decreasing role and decline the rate of a series of esophageal and upper aero digestive system disease. This cross - sectional and case - control study was done in Qaem medical hospital, Mashhad during the years 1384 and 1385, for serum level detection of anti -H.pylori IgG and IgA antibodies in blood samples of both control and case groups. The variables were age, sex and serum test results. 45 patients [39 male and 6 female] and 42 controls [33 male and 9 female] were evaluated. 2 groups were matched for age and sex. Positive IgG and IgA results in patients in order was 3 person [6.6 percent] and 3 person [6.6 person] and in control group 26 person [61.9%] and 12 person [28.5%]. Result [P>0.001] was for healthy group showing the protective effect of H. Pylori against laryngeal cancer. In our study, control group with a meaningful difference was affected by H.Pylori infection. This can be due to a protective effect for H. Pylori against the laryngeal and hypopharyngeal malignancies. Prospective studies and simultaneously evaluation of reflux, H. Pylori infection and the regain of gastric location are suggested

Combination of propofol and tranexamic acid as a protocol of providing optimal surgical condition in comparison with halothane during tympanoplasty

Tympanoplasty is accomplished under general anesthesia. One major drawback of general anesthesia is the increased bleeding encountered, which can interfere with optimal visualization of the microscopic surgical field. We performed a prospective study to compare the effect of combination of propofol and tranexamic acid as a protocol versus halothane on blood loss and the surgeon's subjective assessment of operating conditions during tympanoplasty. 40 patients undergoing tympanoplasty were randomly assigned to receive the mentioned protocol or halothane [n=20]. One surgeon, who was blinded to the anesthetic agent, performed all the operations, and assessed surgical condition, using a grading system of score as follow: 1. minimal or no bleeding 2. modest bleeding 3. significant bleeding 4. severe bleeding. Results were compared in the two anesthetic groups using appropriate statistical tests. There was no difference between the duration of surgery or the intraoperative mean arterial pressure when comparing the two groups. Mean bleeding scores were less over time with above protocol. 80% of the patients had a satisfactory visualization of the surgical field in protocol group, while it was 45% in halothane group. General anesthesia, based on the combination of propofol and tranexamic acid may have the advantage of decreased bleeding compared with conventional inhalation agents, making tympanoplasty technically easier and safer by improving visualization of surgical field. This anesthetic technique may have other applications in otolaryngology, when bleeding within a confined space frequently can interfere with visibility

Epstein - Barr virus antibody titers in non nasopharyngeal head and neck squamous cell carcinoma

The object of this study was to compare EBV antibody titers between various nonnasopharyngeal head and neck SCC and healthy control persons. During 2 years period ELISA was used to investigate titer of different classes of antibody against VCA, EA, and EBNA component of EBV in patient and control group. of 41 patients enrolled in the study 21 were diagnosed by pathological study with pharyngeal and 20 with laryngeal carcinoma. All of different classes of EBV antibody except for EBNA [IgG] in patient group were significantly higher than those in control group. Statistical analysis did not show a significant difference in antibody titers between laryngeal and pharyngeal location of disease as well as between tobacco user and non user groups. Based on the present study there is an association between high EBV antibody titers and non nasopharyngeal head and neck squamous cell carcinoma. Further experiments on tissue samples could investigate the role of EBV in tumor genesis of laryngopharyngeal carcinoma