Evaluation of formaldehyde exposure among gross dissection after modified embalming solution and health assessment.

Mainly embalming fixative contains formaldehyde which is classified as a carcinogen. People who work with cadavers have been at higher risk of cancer after formaldehyde exposure. We have formulated a less-formalin fixative (contained 3.6% formaldehyde,23.8% ethanol, 15% glycerin, and 0.2% phenol in the water) for preserving cadavers. Therefore, the objective of the present study was to evaluate the level of atmospheric formaldehyde indoors and the breathing exposure of medical students during dissection classes. We also analyzed the pulmonary parameters and effects of formaldehyde. The levels of atmospheric formaldehyde indoors and personal breathing exposure were sampled during anatomy dissection classes (musculoskeletal system, respiratory system, and abdominopelvic organ system) using sorbent tubes with air sampling pumps. Samples were then analyzed using Gas Chromatography with Flame Ionization Detector (GC-FID). The mean level of formaldehyde indoor air among the three classes was 0.518 ± 0.156 ppm whereas the formaldehyde level in the personal breathing zone was 0.956±0.408 ppm, which exceeded the recommended exposure standards of international agencies, including NIOSH agency and PEL of Thailand legislation. The laboratory had high humidity, high room temperature, and poor air ventilation. There was a significant difference in FVC, FEV1, and PEF (p < 0.05) between the sexes of students. Comparison pulmonary parameters between students and instructors showed that all parameters of the pulmonary function test had no significant differences. General fatigue and burnings of eyes and nose associated with strong odor were the most common symptoms reported during the dissection classes. The modified embalming fixative was used less formalin with ethanol-glycerin mixture, and it was suitable for the study of medical students, with few side effects of respiratory problems. However, the modified exhaust ventilation with local table-exhaust ventilation and heating-ventilation-air conditioning system performance were urgent issues for reducing levels of formaldehyde indoor air in the dissection room.

Formalin pigment artifact deposition in autopsy tissue: predisposing factors, patterns of distribution and methods for removal.

Formalin pigment deposition is a known artifact of autopsy histology, often anecdotally associated with decomposition of bodies. However, there is minimal data within the forensic literature demonstrating an association between formalin pigment deposition and length of postmortem interval. Furthermore, there is minimal data concerning other predisposing factors and patterns of distribution of formalin pigment deposition. In this study, we compare the amount and patterns of formalin deposition on histology slides from three categories of death: 1) decomposed bodies, 2) critically ill at time of death, and 3) sudden cardiac death. We also compare the effectiveness of two relatively simple histology laboratory methods to remove formalin pigment deposition from histology slides. Amongst the three categories of death, formalin deposition was highest in the decomposed category, second highest in the critically ill category, and lowest in the sudden cardiac death category. The organs most severely affected by formalin deposition were liver/spleen/pancreas and kidneys, and the organs least affected were brain and lung. Formalin pigment deposition correlated with length of postmortem interval. Histologic patterns of formalin deposition included the endothelial lining of vessels, perinuclear compartment of neurons and myocytes, and the basal epithelial compartment of renal tubular epithelial cells. The alcoholic ammonium hydroxide method (AAH) was slightly more effective than the alkylphenol ethoxylate (APE) method for removing formalin pigment, though both methods were effective. Because formalin pigment is strongly refractile under polarized light, a polarization filter can also be useful for distinguishing formalin pigment from other pigments.

Rabbit growth plate morphology in temporary bilateral blocking / Morfología de la placa de crecimiento de conejos durante bloqueo bilateral temporario

Blocking of the growth plate (GP) using plates with screws (tension band plating) is a modern method used to correct deformities and moderate leg length discrepancy in growing children. Determining the duration of temporary bilateral blocking without the occurrence of irreversible changes of GP is of paramount importance important. Methods: Two-month-old Californian breed male rabbits (n=30) were exposed to bilateral blocking of the distal GP of the right femur locking plates with screws for 3, 5, and 7 weeks. The fixators were removed after 5 and 7 weeks in 18 rabbits and 3 weeks after that, animals were sacri!ced. The contralateral limb was used as a control. Histological, histomorphometric, and X-ray analyses were performed. Results: During GP blocking, its height gradually decreased. This decreased was more pronounced after 7 weeks. Destructive changes progressed with an increase in the blocking duration. Three weeks after discontinuation of the bilateral blocking that lasted 5 weeks, the height of the GP signi!cantly increased 1.2 times on the lateral side and 1.9 times on the medial side (p<0.001) compared to the control. When blocking was discontinued after 7 weeks, the structure of the GP was partially restored after 3 weeks, the height of GP signi!cantly increased 1.2 times on the lateral side, and 1.07 times on the medial side (p<0.01) compared to the control. Conclusion: Restoration of the structuralfunctional features of the GP after the removal of the plates depends on the duration of temporary bilateral blocking, which must be taken into account in the clinical setting. (AU)

El bloqueo de la placa de crecimiento (PC) utilizando placas con tornillos (banda de tensión) es un método moderno utilizado para corregir deformidades y alteraciones moderadas en la longitud de las piernas en niños en crecimiento. Es de suma importancia determinar cuál debe ser la duración del bloqueo bilateral temporal sin que ocurran cambios irreversibles en la PC. Métodos: Conejos machos de raza californiana de dos meses de edad (n = 30) fueron expuestos al bloqueo bilateral de la PC distal colocando placas del fémur derecho con tornillos durante 3, 5 y 7 semanas. Los fijadores fueron retirados después de 5 y 7 semanas en 18 de los conejos, y 3 semanas después los animales fueron sacrificados. La extremidad contralateral se utilizó como control. Se realizaron análisis histológicos, histomorfométricos y de rayos X. Resultados: Durante el bloqueo de la PC, su altura disminuyó gradualmente. Esta disminución fue más pronunciada después de 7 semanas. Los cambios destructivos se incrementaron a medida aumentaba la duración del bloqueo. Tres semanas después de la interrupción del bloqueo bilateral que duró 5 semanas, la altura de la PC aumentó significativamente 1.2 veces en el lado lateral y 1.9 veces en el lado medial (p <0.001) en comparación con el control. Conclusión: La restauración de las características funcionales estructurales de la PC después de la extracción de las placas depende de la duración del bloqueo bilateral temporal, lo que debería tenerse en cuenta en el tratamiento clínico de estas alteraciones. (AU)

Safety assessment of antioxidants and color fixatives for the Korean population using dietary intake monitoring.

Food additives such as antioxidants and color fixatives are substances used in food intentionally for technical effect, such as decolorizing or intensifying the color of food. Based on the necessity of re-evaluating food additives for safety and to improve consumer perception, we conducted safety assessments for food additives according to the Risk Assessment Guidelines of the Korean Ministry of Food and Drug Safety. These safety assessments evaluated new risk information based on toxicology data and estimates of dietary intake exposures to food additives in comparison with the acceptable daily intake (ADI). Estimated daily intakes (EDI) of food additives were calculated using food consumption data for the Korean population derived from the Korea National Health and Nutrition Examination Survey and monitoring data based on the analysis of food additives in food products. Unlike contaminants, antioxidants and color fixatives are purposely added as food additives, and they are largely consumed in processed foods. Therefore, EDI was compared with ADI to investigate the likelihood of potentially hazardous effects in humans. The risk likelihoods of food additives, evaluated by comparing the EDI with the ADI, were less than 2% in the total population. Thus, exposure levels to antioxidants and color fixatives do not exceed the ADI. Based on the safety assessments conducted in this study, we estimate exposure to food additives to be within safe limits for all population groups.

Avaliação de diferentes fixadores na preservação das características histológicas de pele de orelha de cães / Evaluation of different fixatives for histological studies in canine ear skin

Os fixadores biológicos desempenham um papel importante na qualidade final da histologia. Na rotina veterinária, a biópsia de pele é um procedimento comum e a escolha do fixador é primordial para resultado final adequado. Os fixadores mais usados são à base de formalina, ainda que sejam tóxicos, cancerígenos, de baixa penetração e de fixação lenta. Mesmo assim, não existe um fixador ideal que substitua as suas qualidades. O objetivo deste trabalho foi avaliar qualitativamente a preservação das características histológicas de pele de cão utilizando diferentes fixadores de tecidos incluídos em parafina, cortados e corados pela hematoxilina-eosina. Utilizou-se uma caneta Punch de 4 milímetros para coletar amostras de pele de orelha em seis cadáveres de cães. Após coleta, os tecidos foram fixados em: (1) Bouin, durante seis horas; (2) Carnoy, durante quatro horas; (3) formaldeído tamponado 10% durante 24 horas, todos sob refrigeração (4ºC). Posteriormente, os tecidos foram processados, cortados e corados em hematoxilina e eosina. As lâminas foram avaliadas, às cegas, por quatro patologistas diferentes, que consideraram aspectos qualitativos a seguir: (1) qualidade da coloração; (2) preservação das características histológicas; e (3) preservação dos limites citoplasmáticos utilizando a escala de LIKERT de pontuação para cada lâmina. O fixador com a maior média de pontuação em todos os itens foi o formol tamponado com 3,76 pontos, seguido pelo Bouin (3,39) e pelo Carnoy (2,52). O formol pode trazer riscos à saúde do profissional que rotineiramente o manuseia, portanto se faz necessária a busca por fixadores com as mesmas qualidades, mas menos nocivos à saúde.(AU)

The biological fixatives have an important role in the final histology quality. In veterinary, routine skin biopsy is a common procedure and the choice of fixative is essential for the final result. The most common fixative is Formalin, even though it is toxic, carcinogenic, and has low and slow penetration. Still, there isn't a fixer which can replace the qualities of formalin. The aim of this study was to evaluate qualitatively the preservation of the histological features of dog skin using different tissue fixative embedded in paraffin, sectioned and stained with hematoxylin - eosin. We used a 4 mm punch pen to collect ear skin samples in six dog cadavers. After collection, the tissues were fixed in: (1) Bouin for 6 hours; (2) Carnoy for 4 hours; (3) 10% buffered formaldehyde for 24 hours, all under refrigeration (4 ° C). The tissues were then processed, sectioned and stained with hematoxylin and eosin. The slides were evaluated blindly by four different pathologists who considered the qualitative aspects below: (1) quality of coloring; (2) preservation of the histological characteristics; (3) preservation of cytoplasmic boundaries using a Likert scale score for each blade. The fixative with the highest mean score on all items was buffered formalin with 3.76 points followed by Bouin (3.39) and Carnoy (2.52). Formaldehyde can bring health a risk of professional routine handling, so it is necessary to search for a biological fixative with the same qualities being less harmful to health.(AU)

The Elnady Technique: An innovative, new method for tissue preservation.

At the Faculty of Veterinary Medicine, Cairo University, there is an increasing number of students but a limited availability of animal cadavers used for dissection, and student exposure to formalin is a known hazard. In order to address these challenges, a new method for tissue preservation was developed, the "Elnady Technique." This method is a modified form of plastination, where the chemicals used are not patented, are inexpensive and locally available, and the process is performed at room temperature. The produced specimens are realistic, durable, have no offensive odor, and are dry, soft and flexible. They can be used to replace the use of animals killed for teaching basic anatomy, embryology, pathology, parasitology and forensic medicine. They have great potential to support training in clinical skills and surgery, including for clinical examination, endoscopy, surgical sutures, and obstetrics simulation.

Optical clearing of fixed brain samples using SeeDB.

Large-scale three-dimensional fluorescence imaging is essential for comprehensive and quantitative understanding of neuronal circuitry. We describe a water-based optical clearing agent, SeeDB, which clears fixed brain samples in a few days leaving many types of fluorescent dyes unquenched, including fluorescent proteins and lipophilic neuronal tracers. This method maintains a constant sample volume during the clearing procedure, an important factor to keep cellular morphology intact. After optical clearing with SeeDB, we can reach a depth of >1000 µm with confocal microscopy. When combined with two-photon microscopy, SeeDB allows us to image fixed mouse brains at millimeter-scale level.

Comparison of fixatives and fixation time for PCR detection of Mycobacterium in zebrafish Danio rerio .

Mycobacteriosis is a common disease of laboratory zebrafish Danio rerio. Different infection patterns occur in zebrafish depending on mycobacterial species. Mycobacterium marinum and M. haemophilum produce virulent infections associated with high mortality, whereas M. chelonae is more widespread and is not associated with high mortality. Identification of mycobacterial infections to the species level provides important information for making management decisions. Observation of acid-fast bacilli in histological sections or tissue imprints is the most common diagnostic method for mycobacteriosis in fish, but only allows for diagnosis to the genus level. Mycobacterial culture followed by molecular or biochemical identification is the traditional approach, but DNA of diagnostic value can also be retrieved from paraffin blocks. Here we investigated the type of fixative, time in fixative before processing, species of mycobacteria, and severity of infection as parameters to determine whether the hsp gene PCR assay (primer set HS5F/hsp667R) could detect and amplify mycobacterial DNA from paraffin-embedded zebrafish. Whole zebrafish were experimentally infected with either M. chelonae or M. marinum, and then preserved in 10% neutral buffered formalin or Dietrich's fixative for 3, 7, 21, and 45 d. Subsequently, fish were evaluated by hematoxylin and eosin and Fite's acid-fast stains to detect mycobacteria within granulomatous lesions. The PCR assay was quite effective and obtained PCR product from 75 and 88% of the M. chelonae- and M. marinum-infected fish, respectively. Fixative type, time in fixative, and mycobacterial species showed no statistical relationship with the efficacy of the PCR test.

Cytogenetic and immunological effects associated with occupational formaldehyde exposure.

Formaldehyde (FA) is a widely used industrial chemical for which exposure is associated with nasopharyngeal and sinonasal cancer. Based on sufficient evidence of carcinogenicity from human investigations, supporting studies on mechanisms underlying carcinogenesis, and experimental evidence in animals, FA status was recently revised and reclassified as a human carcinogen. The highest level of exposure to FA occurs in occupational settings. Although several studies reported FA ability to induce genotoxic responses in exposed workers, not all findings were conclusive. In addition, published studies on the immunological effects of FA indicate that this compound may be able to modulate immune responses, although data in exposed subjects are still preliminary. In this study a group of pathology anatomy workers exposed to FA was evaluated for cytogenetic and immunological parameters. A control group with similar sociodemographic characteristics and without known occupational exposure to FA was also included. Genotoxicity was evaluated by means of micronucleus (MN) test, sister chromatid exchanges (SCE), and T-cell receptor (TCR) mutation assay. Percentages of different lymphocyte subpopulations were selected as immunotoxic biomarkers. The mean level of FA environmental exposure was 0.36 ± 0.03 ppm. MN and SCE frequencies were significantly increased in the exposed group. A significant decrease of the percentage of B cells in the exposed group was also found. Data obtained in this study indicate that genotoxic and immunotoxic increased risk due to FA occupational exposure cannot be excluded. Implementation of effective control measures along with hazard prevention campaigns may be crucial to decrease the risk.

Determination of the lowest concentrations of aldehyde fixatives for completely fixing various cellular structures by real-time imaging and quantification.

The effectiveness of fixatives for fixing biological specimens has long been widely investigated. However, the lowest concentrations of fixatives needed to completely fix whole cells or various cellular structures remain unclear. Using real-time imaging and quantification, we determined the lowest concentrations of glutaraldehyde (0.001-0.005, ~0.005, 0.01-005, 0.01-005, and 0.01-0.1 %) and formaldehyde/paraformaldehyde (0.01-0.05, ~0.05, 0.5-1, 1-1.5, and 0.5-1 %) required to completely fix focal adhesions, cell-surface particles, stress fibers, the cell cortex, and the inner structures of human umbilical vein endothelial cells within 20 min. With prolonged fixation times (>20 min), the concentration of fixative required to completely fix these structures will shift to even lower values. These data may help us understand and optimize fixation protocols and understand the potential effects of the small quantities of endogenously generated aldehydes in human cells. We also determined the lowest concentration of glutaraldehyde (0.5 %) and formaldehyde/paraformaldehyde (2 %) required to induce cell blebbing. We found that the average number and size of the fixation-induced blebs per cell were dependent on both fixative concentration and cell spread area, but were independent of temperature. These data provide important information for understanding cell blebbing, and may help optimize the vesiculation-based technique used to isolate plasma membrane by suggesting ways of controlling the number or size of fixation-induced cell blebs.

[Experimental value of formaldehyde exposure to preserve anatomical findings]. / Valutazione sperimentale dell'esposizione a formaldeide durante il suo utilizzo per la conservazione di reperti anatomici.

Formaldehyde, already classified as potentially carcinogen and recently as "human carcinogen" by IARC, is generally used for fixing and preserving anatomical findings. This reason causes a problem of professional exposure for the operators who use the formaldehyde for this purpose. In this work we present the results of the periodical monitoring which is done for the determination of the exposure at formaldehyde in operating theatres and surgeries, where the operator fill the special container with the anatomical findings andformaldehyde for following tests. The measurements have been done using an instrument that continuously measure the concentration of formaldehyde, based on the infrared spectrometry, in 54 rooms which are operating theatres or surgeries in 9 public hospitals in Campania (Italy). The results show that the long-term exposure limits are not exceeded and that the average of the highest values of concentration obtained during its use was 0.15 +/- 0.04 ppm, that is below the limits. It is important to point out that such a limit was never exceeded during every single measurement. Finally, analyzing statistically the data, we can infer that the probability of exceeding the short-term limit is less than 0.1%, when formaldehyde is used for the purposes mentioned above.

Fluorescence-based fixative and vital staining of lipid droplets in Caenorhabditis elegans reveal fat stores using microscopy and flow cytometry approaches.

The proportions of body fat and fat-free mass are determining factors of adiposity-associated diseases. Work in Caenorhabditis elegans has revealed evolutionarily conserved pathways of fat metabolism. Nevertheless, analysis of body composition and fat distribution in the nematodes has only been partially unraveled because of methodological difficulties. We characterized metabolic C. elegans mutants by using novel and feasible BODIPY 493/503-based fat staining and flow cytometry approaches. Fixative as well as vital BODIPY staining procedures visualize major fat stores, preserve native lipid droplet morphology, and allow quantification of fat content per body volume of individual worms. Colocalization studies using coherent anti-Stokes Raman scattering microscopy, Raman microspectroscopy, and imaging of lysosome-related organelles as well as biochemical measurement confirm our approaches. We found that the fat-to-volume ratio of dietary restriction, TGF-ß, and germline mutants are specific for each strain. In contrast, the proportion of fat-free mass is constant between the mutants, although their volumes differ by a factor of 3. Our approaches enable sensitive, accurate, and high-throughput assessment of adiposity in large C. elegans populations at a single-worm level.

Formaldehyde exposure of medical students and instructors and clinical symptoms during gross anatomy laboratory in Thammasat University.

To study formaldehyde concentrations in the breathing zone and symptoms induced by gaseous formaldehyde exposure of medical students and instructors during gross anatomy laboratory at faculty of Medicine, Thammasat university. Formaldehyde concentrations in the indoor air and breathing zone of medical students were measured during the cadaver dissection. Formaldehyde concentrations in the indoor air and in the breathing zone were ranged from 0.401 to 0.581 ppm (mean 0.491 +/- 0.090) and from 0.472 to 0.848 ppm (mean 0.660 +/- 0.188) respectively. The mean of formaldehyde concentrations in the breathing zone of medical students and instructors was significantly higher than the mean of formaldehyde concentration in indoor air (p < 0.05). The most symptoms were general fatigue (82.7-87.8%), burning eyes (66.2-85.0%) and burning nose (62.5-81.1%). There was no statistically significant difference in burning eye symptom between contact lenses users and no contact lenses users (p > 0.05). Even though formaldehyde concentrations were relatively low, medical students, instructors and cadaver related workers should wear personal protective devices to reduce the effect of gaseous formaldehyde exposure during gross anatomy laboratory or contact cadaver.

Proteomic analysis of RCL2 paraffin-embedded tissues.

Histopathological diagnosis in most of the world's hospitals is based upon formalin-fixed and paraffin-embedded (FFPE) tissues. Although this standard fixation and embedding procedure keeps the tissue in excellent form for morphological and immunohistological analysis, FFPE is inappropriate for nucleic acids and protein studies. We investigated the potential value of RCL2, a new non-toxic fixative, for sparing proteins preserved in paraffin-embedded tissues. Normal colonic mucosa tissue was fixed in RCL2 prior to paraffin embedding (RCL2P), and then processed for quality and quantity of protein conservation, as compared to frozen and FFPE tissues using complementary proteomic analysis approaches. Using 4 different protein extraction protocols, RCL2P tissue consistently showed the highest protein yield. Similar protein patterns were observed with RCL2P and frozen tissues using mono and bi-dimensional electrophoresis. Moreover, membrane, cytoplasmic and nuclear proteins, as well as phosphorylated proteins, were successfully detected using western-blot. Furthermore, protein patterns observed by mass spectrometry analysis after laser-captured microdissection were found to be identical for frozen and RCL2-fixed tissues. At last, immunohistochemistry using various antibodies showed comparable results between both tissue storage methods. We concluded that RCL2 has great potential for performing both morphological and molecular analyses on the same archival paraffin-embedded tissue sample, and can be a new method for investigating protein biomarkers.

[Vertical distribution of formaldehyde concentration and simulated temperature and wind velocity from computational fluid dynamics in a gross anatomy laboratory].

Cadavers for gross anatomy laboratories are typically embalmed in formaldehyde. Thus, medical students and instructors are exposed to formaldehyde vapors emitted from cadavers during dissection. In an attempt to improve the dissection environment, we examined indoor formaldehyde concentrations in a gross anatomy laboratory. Air samples were taken from 20, 110, 160, and 230 cm above the floor between dissection beds to represent areas near the floor, in the breathing zone of sitting students, in the breathing zone of standing students, and near the ceiling, respectively. Formaldehyde vapors were thoroughly diffused from the floor to the ceiling, suggesting that medical students are exposed to similar concentrations of formaldehyde based on distance from the floor. Computational fluid dynamics showed that cadavers are warmed by overhead fluorescent lights and the body heat of anatomy students, and indicated that the diffusion of formaldehyde vapors is increased by lighting and the body temperature of students. Computational fluid dynamics showed that gentle convection from anatomy students and cadavers carry formaldehyde vapors upward; downward flow near admission ports diffuse formaldehyde vapors from the ceiling to the floor in the anatomy laboratory.

Subjective symptoms of medical students exposed to formaldehyde during a gross anatomy dissection course.

The purpose of this study is to investigate the safety of and to try to find the best plan to cope with exposure to FA for students during a gross anatomy dissection course. The FA exposure level and subjective symptoms was estimated. The relationship between exposure to FA and subjective symptoms of irritation were discussed for times; before, in the beginning period, in the middle period, and upon completion of the Anatomy Dissection Course. The geometric means of FA concentration were 32.7 micrograms/m3 (before), 891.3 micrograms/m3 (beginning), 763.3 micrograms/m3 (middle), and 238.9 micrograms/m3 (completion), respectively. Among them, FA-related symptoms were observed in 61.1 percent; 28.0 percent fell strong stress during the course, and 27.4 percent complained that their normal life situation was affected. Our results indicate that such subjective symptoms during the anatomy dissection course were related to the period spent in the anatomy dissection room. Our study suggests that shortening the time of each anatomy dissection practical class and reduction of the number of cadaver tables could help to reduce symptoms.

New alternative methods to teach surgical techniques for veterinary medicine students despite the absence of living animals. Is that an academic paradox?

Due to a raised ethical mentality, veterinary schools are pursuing methods to preserve animal corpses used for surgical technique classes in an attempt to reduce the use of living animals for teaching. Generally speaking, animal and human bodies are usually preserved with 10% aqueous formalin solution especially for descriptive anatomy classes. Other possibilities include the use of glycerol, alcohol and phenol. At present, new fixatives have been developed to allow a better and longer preservation of animal corpses in order to maintain organoleptic characteristics, i.e. colour, texture, as close as possible to what students will deal with living animals. From 2004, in our college, surgical technique classes no longer use living animals for students' training. Instead, canine corpses chemically preserved with modified Larssen (MLS) and Laskowski (LS) solutions are preferred. The purpose of this study was to investigate comparatively the biological quality of preservation of these two solutions and to evaluate students' learning and acceptance of this new teaching method. Although these fixatives maintain body flexibility, LS solution failed to keep an ordinary tissue colouration (cadavers were intensely red) and tissue preservation was not adequate. By contrast, MLS solution, however, did not alter the colouration of cadavers which was fairly similar to that normally found in living animals. A remarkable characteristic was a very strong and unpleasant sugary odour in LS-preserved animals and therefore the MLS solution was the elected method to preserve cadavers for surgical technique classes. The students' feedback to the use of Larssen-preserved cadavers was very satisfactory, i.e. 96.6% of students were in favour of the use of cadavers for surgical training and on average 91.8% (2002-2003) of students preferred the MLS solution as the chemical preserver, whereas only 8.2% elected LS solution for teaching purposes. From the students' point of view (95.1%) the ideal class would be an initial training in MLS cadavers followed by classes with animals admitted to the Veterinary Hospital.

Preservação do sistema genital de chinchila (Chinchilla lanigera) para avaliação em microscopia de luz / Preservation of chinchilla genital system (Chinchilla lanigera) for microscopic evaluation

The preservation of chinchilla genital organs using a fixed solution of paraformaldehyde 10 percent buffered and a saturated solution of Bouin during 4, 12 and 18 hours of fixation, inclusion in paraffin and staining with hematoxylin-eosin was evaluated. The Bouin solution with 12 hours of fixation was the best protocol of fixation for the ovaries, oviduct, uterus and vagina, resulting in little tissue retraction and better cellular integration when compared to the other fixing times (4 and 18 hours). The fixation with paraformaldehyde showed good results of tissues fixation. Chinchilla genital organs can be preserved with paraformaldehyde 10 percent buffered and Bouin solution using 12 hours of fixation.

Formaldehyde exposure in a gross anatomy laboratory--personal exposure level is higher than indoor concentration.

GOAL, SCOPE AND BACKGROUND: Cadavers for gross anatomy laboratories are usually prepared by using embalming fluid which contains formaldehyde (FA) as a principal component. During the process of dissection, FA vapors are emitted from the cadavers, resulting in the exposure of medical students and their instructors to elevated levels of FA in the laboratory. The American Conference of Governmental Industrial Hygienists (ACGIH) has set a ceiling limit for FA at 0.3 ppm. In Japan, the Ministry of Health, Labour and Welfare has set an air quality guideline defining two limit values for environmental exposure to FA: 0.08 ppm as an average for general workplaces and 0.25 ppm for specific workplaces such as an FA factory. Although there are many reports on indoor FA concentrations in gross anatomy laboratories, only a few reports have described personal FA exposure levels. The purpose of the present study was to clarify personal exposure levels as well as indoor FA concentrations in our laboratory in order to investigate the relationship between them. METHODS: The gross anatomy laboratory was evaluated in the 4th, 10th and 18th sessions of 20 laboratory sessions in total over a period of 10 weeks. Air samples were collected using a diffusive sampling device for organic carbonyl compounds. Area samples were taken in the center and four corners of the laboratory during the entire time of each session (4-6 hours). Personal samples were collected from instructors and students using a sampling device pinned on each person's lapel, and they were 1.1 to 6 hours in duration. Analysis was carried out using high performance liquid chromatography. RESULTS AND DISCUSSION: Room averages of FA concentrations were 0.45, 0.38 and 0.68 ppm for the 4th, 10th and 18th sessions, respectively, ranging from 0.23 to 1.03 ppm. These levels were comparable to or relatively lower than the levels reported previously, but were still higher than the guideline limit for specific workplaces in Japan and the ACGIH ceiling limit. The indoor FA concentrations varied depending on the contents of laboratory sessions and seemed to increase when body cavity or deep structures were being dissected. In all sessions but the 4th, FA levels at the center of the room were higher than those in the corners. This might be related to the arrangement of air supply diffusers and return grills. However, it cannot be ruled out that FA levels in the corners were lowered by leakage of FA through the doors and windows. Average personal exposure levels were 0.80, 0.45 and 0.51 ppm for instructors and 1.02, 1.08 and 0.89 ppm for students for the 4th, 10th and 18th session, respectively. The exposure levels of students were significantly higher than the mean indoor FA concentrations in the 4th and 10th sessions, and the same tendency was also observed in the 18th session. The personal exposure level of instructors was also significantly higher than the indoor FA level in the 4th session, while they were almost the same in the 10th and 18th sessions. Differences in behavior during the sessions might reflect the differential personal exposure levels between students and instructors. CONCLUSION: The present study revealed that, if a person is close to the cadavers during the gross anatomy laboratory, his/her personal exposure level is possibly 2 to 3-fold higher than the mean indoor FA concentration. This should be considered in the risk assessment of FA in gross anatomy laboratories. RECOMMENDATION AND OUTLOOK: If the risk of FA in gross anatomy laboratories is assessed based on the indoor FA levels, the possibility that personal exposure levels are 2 to 3-fold higher than the mean indoor FA level should be taken into account. Otherwise, the risk should be assessed based on the personal exposure levels. However, it is hard to measure everyone's exposure level. Therefore, further studies are necessary to develop a method of personal exposure assessment from the indoor FA concentration.

[Chemical content analysis of specimens of human head temporal portion commercially distributed for otological surgery lessons].

Specimens of the human head temporal portion are provided in the United States and distributed commercially for lessons in otological surgery via the internet. Many otologists have obtained and used these specimens in Japan. According to our chemical content analysis, these specimens were found to contain harmful substances as well as large molecule aldehydes and fatty acid methylesters, which are not or only rarely included in the human cadaveric specimens prepared in Japan. We discuss the suggested treatment of these imported specimens, how trial preparation of specimens are much better than the imported items, and the background of the rapid and wide distribution of the imported items in Japan.