Subjective Symptoms of Medical Students Exposed to Formaldehyde during a Gross Anatomy Dissection Course

Cadaver preservative properties of a solution composed of honey, ethyl alcohol, liquid paraffin, distilled water and citric acid: Experiments on rabbit cadavers

The objective of this study is to assess the efficacy of a solution including honey, ethyl alcohol, liquid paraffin, distilled water and citric acid (HEFS) as a preservative for rabbit cadavers, serving as a potential substitute for formaldehyde. The cadavers underwent preservation using three distinct solutions: 10% formalin, 35% alcohol and HEFS. The cadavers were subjected to a total of four sampling events, occurring at 4-month intervals, in order to collect specimens for microanatomical, histological, microbiological, mycological, colourimetric, texture and odour analysis. In terms of hardness, suitability for dissection and joint mobility metrics, the cadavers fixed with HEFS had superior qualities to those fixed with formalin. The fixation quality of HEFS for histological analyses was deemed acceptable, except kidney and intestinal tissues. In texture analysis, differences only in the elasticity parameter (p < 0.05) in the same sampling period. A total of 10 (13.9) bacteria isolates were identified among which, Metasolibacillus meyeri 3 (30%) was predominantly followed by Staphylococcus aureus 2 (20%), Bacillus siamensis, Bacillus subtilis, Pseudarthrobacter oxydans, Bacillus licheniformis, Bacillus subtilis subsp. subtilis with a proportion of 1 (10%), respectively, by both microbiological and molecular analysis. However, no anaerobic bacteria and fungi were isolated. A considerable percentage of the students had the perception that HEFS was appropriate for utilization in laboratory settings due to its absence of unpleasant odours and detrimental impact on ocular and respiratory functions. In conclusion, we consider that HEFS may serve as a viable substitute for formalin solution in the preservation of rabbit cadavers.

Efficacy of urea solution reperfusion to a formalin-embalmed cadaver for surgical skills training

Formaldehyde has been traditionally used for embalming human cadavers for gross anatomy education and surgical skills training. However, exposure to formaldehyde negatively affects human health. This study aimed to assess the efficacy of reperfusing urea solution to a formalin-embalmed cadaver for surgical skills training and then investigate the cadaver's tissue elasticity alteration after being soaked into the urea solution. Twelve surgeons evaluated the similarity of tissue characteristics between the cadaver (embalmed by formalin solution and reperfused by urea solution) and a living human body. Furthermore, the tissue formaldehyde content and mechanical properties of the formalin-fixated femoral skin and artery specimens with or without soaking into urea solution were measured. Results showed that the tactile assessment, skin incision, vessel ligation and suture, and decollement were better and more useful in the cadaver reperfused by urea solution than in the cadaver merely fixated by formalin solution. In the urea-reperfused cadaver, the volatilized, or tissue formaldehyde levels declined. The stiffness and Young's modulus of the femoral skin and artery were also lower in the specimen than in the mere formalin-fixated specimen. In conclusion, reperfusion of urea solution to the formalin-fixated cadaver makes anatomical education and surgical skills training more efficient with fewer requirements for cadaver management.

Comparison of Haptic and Biometric Properties, Bacterial Load, and Student Perception of Fixative Solutions: Formaldehyde Versus Chilean Conservative Fixative Solution with and without Formaldehyde in Pig Kidneys

One of the most widely used solutions to fix and preserve organic tissues is formaldehyde, despite reservations regarding its toxicity and the fact that formaldehyde-embalmed bodies lose their original characteristics. Anatomy laboratories have been replacing formaldehyde with solutions that retain the characteristics of fresh tissue. For this purpose, alternative solutions with a very low concentration of formaldehyde or without any formaldehyde have been analyzed. The objective of this study was to compare biometry, coloration, haptic properties, and bacterial load on animal specimens (pig kidneys) embalmed with formaldehyde, and with Chilean Conservative Fixative Solution with and without formaldehyde (formaldehyde chCFS and formaldehyde-free chCFS). Also, the perception of health and biological science students toward specimens treated with different solutions was assessed. The results indicated that there were no significant differences in specimens' retraction, or bacterial load. Students showed a preference for organs embalmed in formaldehyde chCFS and formaldehyde-free chCFS; indicating that with these treatments they could better visualize structures and that the prosections had greater flexibility and the colors were more similar to those of fresh tissue. Additionally, students recommended the material embalmed in formaldehyde chCFS and formaldehyde-free chCFS for anatomy learning. In contrast, students indicated that formaldehyde-fixation negatively affected their practical experience. In conclusion, embalming with formaldehyde chCFS or formaldehyde-free chCFS provides an advantageous practical experience over the use of formaldehyde and may be an alternative to replace the use of formaldehyde in anatomy laboratories.

Indoor Formaldehyde Concentration, Personal Formaldehyde Exposure and Clinical Symptoms during Anatomy Dissection Sessions, University of Medicine 1, Yangon

The formaldehyde (FA) embalming method, the world's most common protocol for the fixation of cadavers, has been consistently used in medical universities in Myanmar. This study was designed to examine the indoor FA concentrations in anatomy dissection rooms, an exposed site, and lecture theater, an unexposed control site, and to access personal exposure levels of FA and clinical symptoms of medical students and instructors. In total, 208 second year medical students (1/2019 batch) and 18 instructors from Department of Anatomy, University of Medicine 1, participated. Thirteen dissection sessions were investigated from February 2019 to January 2020. Diffusive sampling devices were used as air samplers and high-performance liquid chromatography was used for measurement of FA. Average indoor FA concentration of four dissection rooms was 0.43 (0.09-1.22) ppm and all dissection rooms showed indoor concentrations above the occupational exposure limits and short-term exposure limit for general population. Personal FA exposure values were higher than indoor FA concentrations and the instructors (0.68, 0.04-2.11 ppm) had higher exposure than the students (0.44, 0.06-1.72 ppm). Unpleasant odor, eye and nose irritations and inability to concentrate were frequently reported FA-related symptoms, and the students were found to have significantly higher risks (p < 0.05) of having these symptoms during the dissection sessions than during lecture.

One academic year laboratory and student breathing zone formaldehyde level, measured by gas-piston hand pump at gross anatomy laboratory, Siriraj Hospital, Thailand

This study used a formaldehyde detector tube with a gas-piston hand pump to assess ceiling levels of student breathing zone and gross laboratory environment across the 2018 academic year. The room dimension was 28.6 × 55.48 × 5.5 m. It contained 90 cadavers, each placed on a hinged cover table. We measured before and during nine body region dissections. There was a significant difference (p < 0.01) between student exposure and laboratory environment levels. The highest level was student exposure during body wall dissection (2.7 ppm), the first laboratory; students may accidentally enter body cavities. The latter two were in abdominal (1.85 ppm) and lower limb dissections (1.49 ppm). The three highest environment levels were in different regions; spinal cord removal (1.13 ppm), lower limb (0.72 ppm), and thorax (0.71 ppm) dissection. Only the perineum environment level (0.09 ppm) was below the NIOSH ceiling level (0.1 ppm), which may result from the table covers that had been opened for 2 weeks before measurement. This study finding signified the importance of student personal exposure monitoring and encouraged the academic year measurement. Because each laboratory has unique factors, those affect formaldehyde levels; dissection steps, dissection table design, cadaver storage protocol, and heating-ventilation-air conditioning system performance, for instance.

Spraying urea solution reduces formaldehyde levels during gross anatomy courses

Formaldehyde (FA) is frequently used to embalm human cadavers that are employed to teach gross anatomy to medical and dental students. However, exposure to FA is harmful to both students and educators. The aim of this study was to reduce the FA levels in the anatomy dissection hall by spraying an FA scavenger solution. We measured the changes in FA levels after administering FA scavenger solutions to liquid, wet paper towels, organs, and cadavers containing FA. Among L-cysteine, N-ethyl urea, and urea, the latter was found to have the strongest scavenging power towards the FA in the liquid. The molar concentration of urea that most efficiently reduced the levels of volatilized FA from the wet paper towels was the same as that of the FA. After spraying the urea solution, the volatilized FA levels immediately decreased, reaching their minimum at 60 min, and remained low even after 240 min. Spraying the urea solution onto the organs reduced the levels of FA volatilized from the surfaces of organs but not those from the insides of the organs. In the dissection hall used for the gross anatomy course at Tokyo Medical University, the FA levels were significantly decreased after spraying the urea solution onto the cadavers. Moreover, dissection could be performed without the cadavers putrefying during the 4-month course. These results indicate that various institutes could use urea solution spray to effectively reduce the FA levels in the dissection hall and thus ensure the safety of students and educators.

Learning anatomy through Thiel- vs. formalin-embalmed cadavers: Student perceptions of embalming methods and effect on functional anatomy knowledge

Thiel-embalmed cadavers, which have been adopted for use in anatomy teaching in relatively few universities, show greater flexibility and color retention compared to formalin-embalmed cadavers, properties which might be considered advantageous for anatomy teaching. This study aimed to investigate student attitudes toward the dissection experience with Thiel- compared to formalin/ethanol-embalmed cadavers. It also aimed to determine if one embalming method is more advantageous in terms of learning functional anatomy through the comparison of student anterior forearm functional anatomy knowledge. Student opinions and functional anatomy knowledge were obtained through use of a questionnaire from students at two medical schools, one using Thiel-, and one using more traditional formalin/ethanol-embalmed cadavers. Both the Thiel group and the formalin group of students were surveyed shortly after completing an anterior forearm dissection session. Significant differences (P-values <0.01) in some attitudes were found toward the dissection experience between cohorts using Thiel- vs. formalin-embalmed cadavers. The Thiel group of students felt more confident about recognizing anatomy in the living individual, found it easier to identify and dissect anatomical structures, and indicated more active exploration of functional anatomy due to the retained flexibility of the cadaver. However, on testing, no significant difference in functional anatomy knowledge was found between the two cohorts. Overall, although Thiel embalming may provide an advantageous learning experience in some investigated areas, more research needs to be carried out, especially to establish whether student perception is based on reality, at least in terms of structure identification. Anat Sci Educ 11: 166-174. © 2017 American Association of Anatomists.

Influence of bone density and implant drill diameter on the resulting axial force and temperature development in implant burs and artificial bone: an in vitro study

PURPOSE

The aim of this study was to determine how the bone density affects the temperature development in artificial bone and drill.

METHODS

Ten single drills with diameters of 2.2, 2.8, 3.5, and 4.2 mm were used on four artificial bone blocks (density I-IV), with constant speed and external irrigation. Temperature measurement in blocks and drills was done by infrared camera. The resultant axial force was measured, and light microscopic examinations of the drills were performed before and after preparation.

RESULTS

The block density has a greater influence on resulting axial force than the drill diameter (D1 = 2.2 mm, 4.11 ± 0.64 N; 4.2 mm, 9.69 ± 0.78 N vs. D4 = 2.2 mm, 0.5 ± 0.18 N; 4.2 mm, 1.23 ± 0.08 N). For the narrowest drill, a decrease in bone density caused a significant temperature increase in the bone and drill. However, for the thickest drill, no thermal differences were found in the bone but were seen in the drill itself (D1 = 2.8 mm vs. D4 = 2.8 mm; bone p < 0.0001, drill p < 0.0001; D1 = 4.2 mm vs. D4 = 4.2 mm; bone p = 0.5366, drill p = 0.0411). An increase in the drill diameter in the highest bone density led to a significant thermal increase in the bone and drill. However, for the lowest bone density, thermal changes were observed only in the bone (D1 = 2.8 mm vs. D1 = 4.2 mm; bone p < 0.0001, drill p < 0.0001; D4 = 2.8 mm vs. D4 = 4.2 mm; bone p < 0.0102, drill p = 0.1784).

CONCLUSIONS

Thermal development depends on bone density with increasing density causing a temperature rise. However, this effect is reduced with increasing drill diameter. This may be important with regard to bone reactions and also in terms of tool wear.

Pulmonary function test in formalin exposed and nonexposed subjects: A comparative study

Background:

The main function of the lung is gas exchange, which can be assessed in several ways. A spirometer measures the flow and the volumes of the inspired and expired air. The thoracic and abdominal muscle strength plays an important role in pulmonary function and diffusing lung capacity.

Aims and Objectives:

The aim of this study was to assess the effects of formalin exposure on the pulmonary function to compare with healthy individuals. To assess the chronic effects of formalin exposure on Pulmonary function tests (PFTs) in the faculties, lab technicians and attender of the Department of Anatomy and Pathology of SRM Medical Hospital and Research Centre, Kattankulathur.

Materials and Methods:

This prospective study was carried out in 50 healthy formalin exposed subjects (at least 5 years exposure) from Department of Anatomy and Pathology of SRM Medical College Hospital and Research Centre, Kattankulathur and 50 healthy controls of same age group of this study were included after obtaining ethical clearance and consent ‘Easy One Pro Spirometer (Ndd Medical Technologies, Cheshire SK 101LT, United Kingdom) was used to find out the PFT.

Results:

Student's t-test was applied to compare the PFT parameters between formalin exposed and formalin nonexposed group. There was a significant difference in mean and standard deviation of pulmonary parameters with the P < 0.005 in formalin exposed, which shows that they have lesser ventilatory drive.

Conclusion:

The formalin exposed subjects in our study presented with a mixed disorder of both obstructive and restrictive type. We also found that there was a negative correlation of pulmonary function with that of the degree and duration of exposure to formalin.

Human body preservation - old and new techniques

This review deals with the art of (anatomical) embalming. The first part contains a brief historical review of the history of embalming, starting with ancient cultures such as the Egyptians and the lesser known Chinchorro culture, then going down the centuries and describing the anatomical techniques developed over the last two centuries. The second part deals in detail with the chemicals used for embalming purposes. The third part deals with several approaches to evaluating embalming methods, their suitability for biomechanical testing, antimicrobial properties, histological appearance, and usability. The fourth and final part analyze the European Biocidal Products Directive (98/8/EC) in the light of embalming.

Student perceptions of an upper-level, undergraduate human anatomy laboratory course without cadavers

Several programs in health professional education require or are considering requiring upper-level human anatomy as prerequisite for their applicants. Undergraduate students are confronted with few institutions offering such a course, in part because of the expense and logistical issues associated with a cadaver-based human anatomy course. This study describes the development of and student reactions to an upper-level human anatomy laboratory course for undergraduate students that used a regional approach and contemporary, alternative teaching methods to a cadaver-based course. The alternative pedagogy to deliver the curriculum included use of commercially available, three-dimensional anatomical virtual dissection software, anatomical models coupled with a learning management system to offer Web-based learning, and a new laboratory manual with collaborative exercises designed to develop the student's anatomical skills and collaborative team skills. A Likert-scale survey with open-ended questions was used to ascertain student perceptions of the course and its various aspects. Students perceived that the noncadaver-based, upper-level human anatomy course with an engaging, regional approach is highly valuable in their learning of anatomy. anatomy.

Non-cancer effects of formaldehyde and relevance for setting an indoor air guideline

There is considerable recent focus and concern about formaldehyde (FA). We have reviewed the literature on FA with focus on chemosensory perception in the airways and lung effects in indoor environments. Concentrations of FA, both personal and stationary, are on average in the order of 0.05 mg/m(3) or less in Europe and North America with the exception of new housing or buildings with extensive wooden surfaces, where the concentration may exceed 0.1 mg/m(3). With the eye the most sensitive organ, subjective irritation is reported at 0.3-0.5 mg/m(3), which is somewhat higher than reported odour thresholds. Objective effects in the eyes and airways occur around 0.6-1 mg/m(3). Dose-response relationships between FA and lung function effects have not been found in controlled human exposure studies below 1 mg/m(3), and epidemiological associations between FA concentrations and exacerbation of asthma in children and adults are encumbered by complex exposures. Neither experimental nor epidemiological studies point to major differences in susceptibility to FA among children, elderly, and asthmatics. People with personal trait of negative affectivity may report more symptoms. An air quality guideline of 0.1 mg/m(3) (0.08 ppm) is considered protective against both acute and chronic sensory irritation in the airways in the general population assuming a log normal distribution of nasal sensory irritation.