[Evaluation of formalin substitution fixative effects on H and E staining results]

These days, Formalin is considered as a good and cheap fixative, but very harmful for human health. It is one of chemical components which has traditionally been used as a routine fixative in anatomy and pathology laboratories; however, their personnel are still under its harmful effects. In this study, effects of formalin substitution fixatives on H and E staining results were investigated. Three kinds of formalin substitution beside 10% buffered formalin were used in this study. They were named and recognized as B, K, M. Pieces of rabbit liver were placed in dishes which contained each kind of above mentioned fixatives. After 24 hours, tissues were processed and embedded by paraffin followed by sectioning, staining by hematoxylin and eosin. Then, they were studied under light microscope. Overall, preserving of tissue structures and staining results with M fixative were more desirable. In general, two out of the three fixatives, with some advantages and disadvantages rather than formalin, made tissues fixed desirably, and had acceptable results in staining. Thus, they can be known as suitable substitution for formalin

[Electromagnetic radiation effects on embryonic mesenchymal tissue]

With increasing use of modern technology in some industries and communicating instruments and also electromagnetic field [EMF] due to transmission of high power electricity, radar beam, wireless instruments etc. study of electromagnetic radiation effects become a new subject these days. Since there is not much information regarding the effects of this kind of energy on live body tissues, present study was performed to determine these effects. In this study, 30 mice embryo were used and divided into two groups [case and control] of 15 each. Oral cavity tissues were selected for the examination. An electromagnetic producer machine which produced a field with frequency of 27 MHz and power output 493 watts. In the case group, mesenchymal tissues were affected by EMF for 20 mins. then were cultured on nutrient agar for 24 hrs. In the case group, the mesenchymal compartments contain cartilage tissue and lost their epithelium in compare with those control which had no cartilage tissue and integrated epithelium. The study showed that high frequency EMF without other environmental stimulation such as warmth can produce metaplasia in embryonic mesenchymal tissues. Thus, avoiding from exposition to EMF for pregnant women is recommended

Assessing the compatibility rates of governmental dentistry centers of Tehran with desirable infection control criteria and the factors involved, 2004

Dentistry systems should meet criteria of infection controls. Higher compatibility will result in more desirable system situation. To determine the conformation rates of governmental dentistry centers located in south and southwest of Tehran with desirable criteria for infection control and the affecting factors. This was a cross-sectional descriptive study performed on 74 governmental dentistry centers in south and south west of Tehran province in 2004. Achecklist including 10 axes was used to investigate 141 identities for their conformity to meet infectious control criteria via direct observation. Following the analysis of data by SPSS-V11.5 and the application of t-test and Chi square test, the situation of centers were placed into three rankings as follows: Under expected [75%]. Their desirable degree was tested by 10 presumptive effective factors. Among 74 investigated centers in the study, 40 centers were located in the south of Tehran, 24 in Shahr-e-Rey, and 10 in Islamshahr with a mean conformation to desirable criteria of 56.3, 52.5, and 60.1%, respectively. Collectively, 12 centers [16.2%] were placed in under expected, 60 centers [81.1%] in medium, and 2 centers [2.7%] in desirable ranking. Availability of dentists with specialty, being a member of academic staff, and the presence of dental clinic in university hospitals were found to produce a significant impact towards the desirability, statistically [p<0.05]. According to our findings, monitoring and solving the problems of centers with under expectable limit to meet the desirable criteria is suggested

Histopathologic evaluation of the effect of microwave irradiation on fixation of kidney tissue

Post-mortem structural changes in tissues cause technical difficulties in accurate histo-pathologic interpretation. In the present study, we evaluated the effects of microwave irradiation before tissue fixation on preventing post mortem autolysis and accelerating the process of tissue fixation in the kidneys. Twenty-four chickens randomly were divided into 8 groups of 3 each. They were slaughtered and stored at room temperature. At 0, 1, 3, 5, 10, 15, 20 and 25 hours the kidneys were removed from chickens. The right kidneys were used as controls and fixed by conventional method through immersing in 10% buffered formalin; all the left kidneys were first irradiated by microwave [MWI; 30sec/450 watt] and then immersed in 10% buffered formalin. Kidney tissue samples were prepared according to standard routines, sliced into sections measuring 5 microns and stained by hematoxylin and eosin; next, these slides were examined through a light microscope. Morphologic study showed no difference in tissue preservation between the two methods till 20 hours post-mortem; however, at 25 hours, samples that had been fixed according to the standard methods revealed marked post-mortem structural degeneration while samples receiving microwave irradiation before fixation had preserved their original structure to a greater degree. Microwave irradiation before fixation of kidney tissue that has been dead for up to 25 hours results in greater structural preservation as compared to fixation by routine methods. We recommend further studies, preferably by using image analyzing, immunohistopathology and electronic microscopy to scrutinize minute structural changes in detail

Diffuse Lamellar Keratitis after LASIK: prevalence, natural course, and final visual outcomes in stage III or IV

To evaluate the prevalence, natural course, and final visual acuity in patients with stages III or IV of diffuse lamellar keratitis [DLK] following Laser in situ keratomileusis [LASIK]. In this descriptive study, records of all the patients who underwent LASIK surgery in two private excimer laser clinics were reviewed. According to Linebarger- Lindstrom-Hardten classification, ocular findings of patients with DLK were classified. There was no preoperative systemic or corneal contraindication for LASIK. Age, preoperative refraction and best corrected visual acuity [BCVA], type and duration of treatment, postoperative refraction, topography, final BCVA, possible side effects of medications and complications were reviewed. Out of 4097 eyes of 2131 patients, DLK above stage II developed in 28 eyes [0.68%] of 14 patients [0.66%]. DLK was in stage II-III in 78.6%, stage III in 10.7%, and stage IV in 1.7%. None of these patients had history of allergies. Treatment consisted of frequent betamethasone drops alone or with ointment and oral systemic prednisolone. Interface irrigation was not performed in any patients during the course of treatment. Average interval from LASIK to diagnosis was 3 +/- 1.5 days. Patients were treated for an average duration of 20 +/- 13.2 days and were followed for an average duration of 11 +/- 10 months. Average preoperative BCVA was 0 LogMAR [20,20] and final post LASIK and DLK vision remained the same. Prevalence of DLK stages III and IV is considered insignificant as compared to the enormous number of candidates for LASIK surgery [0.68%]. All patients with DLK stages III and IV responded well to immediate topical and systemic corticosteroid therapy and on follow up there was no adverse effect on final BCVA