Dental curriculum revision in Iran: dentists' perspective on achievement of essential competencies through national curriculum

Based on the current emphasis on competency-based education, as a part of need assessment phase of dental curriculum revision in Iran, in the present study the dental graduates' perspective concerning the minimum competency requirements for an Iranian general dentist has been investigated. Based on the three available major competency documents in the literature a questionnaire was developed in which the participants were asked to indicate their opinion about the necessity of each of the 142 stated competencies for an Iranian general dentist [Yes/No], and to state the degree to which they believed the current curriculum covers each competency [Completely, Partially, Not at all]. In an annual meeting in June 2008, the provincial chief dental managers were asked to distribute the questionnaires among general dentists in their province [10 questionnaires in each province]. The managers posted back the completed questionnaires to the researchers. Of 300 questionnaires distributed in the 30 provinces of the country, 250 questionnaires [83%] were returned. While most of the participants considered the competencies as necessary for an Iranian dentist, less than 40% of the respondents believed that the graduates acquire the most required competencies of the profession during the current educational program. A necessity exists for curriculum revision. In addition to clinical skills, in this revision more emphasis also should be placed on the non-clinical part of the curriculum

[Study of glycoconjugates terminal sugars during gonadogenesis in rat by lectin histochemical method]

Gonadogenesis is a complex developmental process which is regulated by molecular interactions such as cell surface and extracellular matrix [ECM] Glycoconjugates terminal sugars. The aim of this study was to determine Glycoconjugates terminal sugars expressions and changes during Gonadogenesis in Rat using Lectin histochemical technique. To determine of glycoconjugate terminal sugers by Lectin histochemistry method, thirty Wistar Rat embryos at different stages from days 12 to 16 of gestation were fixed in formalin, embedded in paraffin and cut in to 5microm thickness sections serially. The sections were incubated with different HRP- lectins from Lotus tetragonolobus [LTA], Maclura pomifera[MPA] and Arachis hypogaea or Peanut [PNA], that are specific for terminal sugars L-Fuc [alpha2-4]GlcNAc, Gal[beta1-3]GalNAc and D-Gal[beta1-3]DGalNAc respectively. On the basis of colorimetery data that was determined by blind's method, sections were graded and SPSS statistic soft ware and kruscal Wallis tests were used for comparing different embryonic stages. Our finding showed that LTA did not react with developing gonads at gestational day 12[E12]. LTA reactivity was found in extracellular matrix [ECM] of developing gonads from E14 through E16 [P<0.05] and PGCS as well as surface epithelium at E16 [P<0.05]. Surface epithelium were reacted with MPA from E12 to E14 and increased LTA reactivity at E16 [P<0.05]. ECM was reacted with MPA at E14 and diminished at E16 [P<0.05]. LTA reactivity was found in PGCS at E16. PNA did not react with developing gonads at gestational day 12[E12] but its reaction was started with PGCS from E14 and increased to E16 [P<0.05]. In addition, PNA reactivity was started with ECM and surface epithelium from E14 and increased at E16 significantly [P<0.05]. According to our result, it is concluded that the expression and changes of glycoconjugates with terminal sugars L -Fuc [alpha2-4] GlcNAC, and D-Gal [beta1-3] DGalNAC are regulated developmentally during rat gonadogenesis

[ effect of formaldehyde on somniferous tubules of Balb/c mice]

To examine the effect of formaldehyde on somniferous ducts of laboratory animals. This study investigated 24 male Balb/c mice 20 days old that randomly divided into experimental and control groups. The Experimental group was administered every other days at the rate of 0.25 mg/kg formaldehyde intrapritoneally for 20 days. The control group received the same volume of normal saline during the same period of times. At the end of exposure time, the sample of both groups were anesthetized and Transected. Their removed testies were processed, serially sectioned and histochemically studied. Our findings showed that the mean of internal diameter of somniferous tubules decreased significantly in experimental group compared to control group while the mean of external diameter was the same in both groups. Furthermore the prolifration rates of I and II spermatocytes were decreased significantly in experimental group compared to control group. The findings indicate that administration of formldehyde can influence the structure of male reproductive system and affect on spermatogenesis procedure

Immediately loaded Xive and Nisastan implants; the effect of macro-design on distribution of strain in surrounding bone: a finite element analysis

The fixture macro-design is one of the most important factors influencing the implant's primary stability and micro-motion. The aim of this study was to evaluate the peri-implant stress distribution and micro-motion in 2 types of immediately loaded implants in order to determine the best design by using finite element analysis. In this experimental study the accurate pictures of the two fixtures [ILS and Xive] were taken by a digital camera. By using computer simulation technique, a three dimensional finite element model was inserted in a simulated mandibular bone. The displacement and Von Misses stress was recorded after loading. It was found that, the primary stability of ILS was greater [152 micro a] than Xive [284 micro m]. Likewise, ILS exhibited favorable behavior in stress distribution. Moreover, the maximum stress concentration in Xive peri-bone [almost equal to 30MPa] was lesser than Nisastan [almost equal to 37MPa]. The ILS macro-design provides better primary stability and stress distribution, with less stress around the Xive

effect of plaque on peri implant soft tissue health: a 4 years follow up study

Microbial plaque is the main etiologic factor which causes disease in soft tissue around dental implants. The purpose of this study was to evaluate the effect of plaque on health indicies of soft tissue around dental Implants. 45 patients with 211 dental implants were examined clinically for four years after prosthodontic treatment. Plaque index and health indices of soft tissue including pocket depth, attachment level, bleeding index, and gingival index were measured. The results were compared in two groups of zero and non zero plaque. The repeated measured ANOVA and Friedman test were used for statistical data analysis. The results of this study showed that in the first group, in which the plaque index was zero, probing pocket depth, probing attachment level, bleeding index, and gingival index were lower than in the second group. According to the results of this study, aggregation and increase of plaque around dental implants decreases the health level of soft tissue around dental implants and its continuation may cause disease in protective tissues of the implant

[Factors associated with esophageal cancer in the southeast part of the Caspian Sea]

Introduction: Esophageal cancer is the 8th prevalent cancer [4% of all] around the world and the sixth leading cause of death from cancers .The Northeastern parts of Iran [Caspian littoral areas] are one of the most prevalent areas of esophageal cancers in the world

Objective: In this study, we examined relationship between esophageal cancer tumor histology and variables like age and sex, in pathologically confirmed cases in the Northeastern of Iran [Caspian littoral margins]

Materials and Methods: This descriptive cross-sectional study was conducted in the health care services and pathologic centers in Golestan Province. All pathologically confirmed esophageal cases were enrolled in the study and demographic data were listed. Data were analysed with SPSS-10 software. Variables were compared with one-way ANOVA and Mann-Whitney tests for continuous variables and chi-square for nominal/categorical variables. Level of significance was set at p-value less than 0.05

Results: Four hundred and ninety one pathologically confirmed esophageal cancer cases from 1996 through 2000 were included in this study. Squamous cell carcinoma was the dominant tumor histology in this study and it was more common in females. We found that tumor histology is highly related to gender and this association is independent of age factor. Our finding revealed that this association is only applicable to older age groups [older than 50]

Conclusion: Results from this study suggested that demographic factors might be different in esophageal cancer cases in different geographic areas. Our finding can be a reflection of distinctive etiology for esophageal cancer in the Caspian littoral areas

[Lectin histochemistry epididymal epithelium in mouse]

Introduction: Several different cell types have been identified morphologically in the epididymal epithelium in male mammals. They absorb luminal fluid and secret sperm-maturation glycoconjugates. Lectin histochemical method is useful for detection of glycocojugates with specific terminal sugars

Objective: This study surveys the distribution of glycoconjugates containing terminal sugals in cells of different areas of epididym and its canal sperms by the use of lectins

Materials and Methods: Sample of epididymal tissue was obtained from 30 adult male BALB/C mouse. After fixation and routine laboratory process, 5 microm sections was prepared from paraffin blocks. Slides were exposed to lectins with lectin-histochemistry. Then the slides were assessed by light microscope and graded reaction intensity in different cells

Results: Basal cells reacted to MPA, SBA and principal cells to all of lectins. Reaction intensity in essential cells was different as compared to various lectins and a special lectin in different areas of epididym. Narrow cells reacted to LTA, MPA and clear cells reacted to all of lectins. There wasn't any reaction in basal lamina and interstitial tissue except for MPA

Conclusion: epididymis secrets many sperm-maturation related glycoconjugates. Different reactions in different probably synthesieed glycoconjugates in basal cells due to inability to reach lumen and limited reaction in membrane, are used for repair and reconstruction of membrane. Faint or lack of reactions in caput of epididymis and appearance in corpus principal cells indicates that these cells in caput are involved in fluid absorption and/or glycoconjugates secretion in corpus. Epididymal sperm transit are accompanied with focuse content increasing and alternation in other terminal sugars

[Lectin histochemical survey of glycoconjugates role in development of anterior pituitary gland in rat]

Adenohypopliysis originates from the oral ectoderm that first appears as an invagination named Rathkes pouch. The development of the anterior pituitary gland [APG] is dependent on several factors such as induction, interaction with the microenvironment and certain genetic factors. These regulate developmental processes such as cell migration, proliferation, differentiation, and morphogenesis. Glycoconjugates e the important components of extracellular matrix and cell surface and have an important key role during embryogenesis. In this study we used lectin heistocliemichal technique as a tool to study distribution of glycoconjugates d their changes during histogenesis of APG. Horse radish peroxidase [HRP] labeled focus specific lectins, from Aleuria aurantia [OFA] Ulex europeus [UEA-I] and Lotus tetragolobus [LTA] were used on 5 micron paraffin sections of rat embryos [n=60] from days 10 of gestation [El0] to the time of birth. The result of this study demonstrated that the reaction of APG cells with OFA started from E, and its reactions increased with proceeding differentiation. Some cells reacted with UEA-1 from Ell and increased to El6 and then decreased afterward. LTA did not react with any cells during development. Our finding also indicated that glycoconjugates with terminal sugar Fucose may play a key role in APG development. In conclusion, the glycoconjugates on the cell surface and extra cellular matrix might be involved in regulation of embryonic development such as APG

[Cell surface molecular differentiation during rat adenohypophysis morphogenesis using lectin histochemistry]

Introduction: It is well known that glycoconjugates on the cell surface of embryonic cells as well as extracellular matrix [ECM] are involved in many developmental phenomena including cell differentiation and maturation. These molecular events have not received proper attention during pituitary cell differentiation. The purpose of this study was to investigate glycoconjugate distribution on cell surface during adenohypophysis embryogenesis

Material and Methods: Using lectin histochemistry, 5microm normalin fixed, paraffin embedded Rat embryonic sections from day 10 to 20 of gestation [N=90] were incubated with different HRP-lectins from Triticum vulgaris [WGA] Arachis hypogaea [PNA] and Griffonia simplicifolia [GSA1- B4] specific for terminal sugars Sialic acid, N-acetyl galactosamine and alpha-D- galactose ofcomplex glycoconjugates respectively. On the basis of intensity of staining that was determined by Gong's method, sections were graded and non-parametric statistical test [Kruskal Wallis] was used to compare differences between samples

Results: The results demonstrated that the reaction of adenohypophysis cells with WGA started from gestational day 13[E13] and increased with proceeding differentiation during the following days [P<0.05]. A few cells reacted with PNA from E13 and increased to E14 [P<0.05] and then identified to E17 and decreased afterward [P<0.05]. GSA1-B4 didn't react with any cells during development. Our findings also indicated that glycoconjugates with terminal sugars sialic acid and N-acetyl galactosamine may play a critical role in adenohypophysis development

Conclusion: The appearance and changes of Glycoconjugates on the cell surface with terminal sugars such as acid sialic and N-acetyl galactosamine may play a key role in tissue interactions and lead to developmental changes in certain embryoniorgans such as adenohypophysis

[Assessment of sialic acid distribution in mouse epididymis]

Previous studies have shown that epididymal epithelium and its secretions are critical for sperm maturation. These secretions contain many glycoconjugates with sialic acid terminal sugar. This terminal sugar by intervening in cellular interactions and masking surface receptors has an important role in sperm maturation and protection. Moreover, lectins have been employed as useful probes to detect the presence of glycoconjugates with specific sugar residues such as sialic acid. Considering the importance of sialic acid, distribution of this terminal sugar in different parts of mouse epididymis was studied by means of lectin histochemistry. For this purpose, epididymal tissue species were obtained from 15 adult male BALB/c mice. After fixation and routine laboratory process, 5 pm sections prepared from paraf3n blocks. Slides were exposed to lectins with lectin-histochemistry. For this purpose, Wheat germ agglutinin [WGA], specific for sialic acid, was employed. Then they assessed with light microscope. The rate of reactions in epithelial cells and spermatozoa were significantly different n different parts of epididymis. In the manner that, in spermatozoa, stereo cilia and luminal surface the least reactions were seen in caput, while the most reactions were seen in cauda. Epithelial cells, too, showed less reaction in caput comparing to corpus and tail of epididymis. Sialic acid has been identified in many glycoproteins secreted by epididymis and is necessary for sperm maturation. It seems that this maturation happens mostly in bod2 and tail of epididymis during epididymal transit. Increase in sialic acid content of spermatozoa during epididymal transit is probably due to the secretion of glycoconjugates containing this component by epididymal principal and flask cells

case of bilateral agenesis of the femur

Bilateral femoral agenesis is a rare anomaly. To the best of our knowledge, only three cases of simple congenital anomaly and three cases associated with femoral facial syndrome have been reported. Here, we describe a simple form of bilateral femoral agenesis observed in one of the 2 dead fetuses delivered after termination of a 24-week twin pregnancy of a normal mother. Post-mortem x-ray examination confirmed the agenesis of both femurs and also left fibula

Developmental changes of glycoconjugates in early mouse embryonic neuroepithlium, notochordal and surrounding mesenchymal interactions

During early neural tube formation, the notochord is essentialfor the induction of ectoderm and for the subsequent differentiation of theneuroepithelium forming diverse cell types in the neural tube. Due to thekey role of the glycoconjugates in many developmental events, the earlydistribution of these molecules in early notochordal interaction withadjacent tissues were studied. Material and Paraffin fixed 5m sections of days 10 to 14 of mouse embryo were processed for histochemical studies by using horseradish peroxidase labelled DBA, VVA-B4, WFA, UEA-1 and OFA lectins.These lectins have binding specificity for D-GalNac and a-fucose sidechains of the glycoconjugates. Histochemical analysis revealed that notochord and itsintermediate extracellular fluid show extensive reaction with the floor plateof neural tube on 10th day, using OFA. This reaction was absent in thenext day but a sever reaction was observed in the floor plate region. Theresults revealed a reaction in venteral portion of notochord with VVA-B4and it expanded in to gut tube. Furthermore, a WFA-reaction was observedin the notochord and some of adjacent mesenchymal cells, but UEA-1 and DBA, don't showed any reaction. The expression of the GalNac and also fucosilatedglycoconjugates is stage-dependent and thus probably geneticallyregulated. The timing and distribution of lectin reactions suggest that thesemolecules [GalNac and fucose] may play a role[s] in notochordalinteractions and subsequent formation of the adjacent tissues

Cigarette smoke/ethanol-induced limb defects in mouse embryos

We have produced a spectrum of limb defects in developing mouse embryos by exposing the mother to smoke from cigarettes with different nicotine concentrations, ethanol, and a combination of ethanol and cigarette smoke. The critical time of exposure was determined to be during day 10 of gestation [vaginal plug=day 0]. This time is prior to the critical events which occur between the apical ectodermal ridge and the developing limb mesenchyme. When pregnant animals were exposed to smoke from two high-nicotine cigarettes [at 10:30 a.m. and 11:30 a.m. on day 10], no limb defects were observed. If ethanol was given [0.015 mg/g 25% i.p. in two doses on the morning of day 10] one% of offspring showed a limb defect. By contrast, exposure to a combination of cigarette smoke and ethanol resulted in 43% [44/102] of newborns developing both fore - and hindlimb defects. Birth weight was reduced by about 33% in animals carrying the defects. When mesenchyme cells beneath the limb apical ectodermal ridge were examined two days after teratogen exposure, striking changes in cell shape and size were evident. In as much as the incidence of mesenchymal changes in the limb buds seen on day 12 parallels the incidence of malformations seen in newboms, we postulate that anomalous limb development is secondary to the events occurring in the limb mesenchyme. We conclude that critical stages of development occur in the limb buds, and therefore certain teratogens or combinations of teratogenic agents may interfere with their normal development

Association of craniofacial and cardiac defects in phenytion-treated mouse newborns

The fetal hydantoin syndrome is characterized by unusual fades, increased incidence of cleft lip and/or palate, hypoplasia of the distal phalanges and an increased incidence of cardiac defects. The purpose of this study was to identify phenytoin as a cardiac teratogen in A/Jax mice and to identify the primordial cardiac structures affected. We have found that phenytoin can be embryopathic when the embryo is exposed during critical stages of development. Our results also indicate that a high incidence [53%] of cardiac malformations coexist with facial clefts. It is hypothesized that cardiac septation and facial processes undergo "critical" stages in their development at the same time and are therefore concurrently affected by agents, either environmental or genetic, which interfere with their normal morphogenesis