The Journal of Plastination

Published in J. Int. Soc. Plast. 19:20-21 (2004)

Ascaris Plastination through S10 Techniques

AUTHORS:
M.H. ASADI , A. MAHMODZADEH
affiliations:

Baghiatollah  University of Medical Sciences, Department of Anatomy, and Iran University of Medical Sciences, Tehran, Iran.

ABSTRACT:

Ascaris Lumbricoides is the largest of the common nematode  parasites of the human digestive system. It has a world-wide distribution and is very common in regions with poor sanitation. Because of this association with man, Ascaris' impact on human health is taught in medical institutions around the world. Different techniques are used to prepare Ascaris for educational purposes in medical colleges. One method is immersion and storage of the nemotode specimens in formaldehyde. A second less common method is preservation in alcohol. Histological cross sections are also utilized in some teaching laboratories . The disadvantages to teaching with specimens stored in formaldehyde or alcohol is that they are wet and these solutions are associated with noxious odors and potential health problems in humans. Additionally, specimens stored in formaldehyde or alcohol often present problems in transportation for use outside institutions . The disadvantage of histologic specimens is their limitation in scope. The purpose of this study was to perform plastination of Ascaris Lumbricoides specimens using the S10 technique. This procedure produced specimens which are dry, odorless and easy to handle while maintaining the natural shape of the specimen. Ascaris Lumbricoides preserved in this manner can be easily used for demonstration in educational courses working with medical students as well as public health education of the general population.

KEY WORDS:

plastination; silicone; S10; Ascaris

*CORRESPONDENCE TO:

M.H. ASADI: Fax: 0098 21 66956253; E-mail: asadiamh@yahoo.com

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Article Statistics

Volume: 19
Issue: Fall
Allocation-id: 0000

Submitted Date:June 16, 2004
Accepted Date: October 7, 2004
Published Date: December 31, 2004

DOI Information:       https://doi.org/10.56507/EDVF4592

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Article Citation

The Journal of Plastination (April 22, 2024) Ascaris Plastination through S10 Techniques. Retrieved from https://journal.plastination.org/articles/ascaris-plastination-through-s10-techniques/.
"Ascaris Plastination through S10 Techniques." The Journal of Plastination - April 22, 2024, https://journal.plastination.org/articles/ascaris-plastination-through-s10-techniques/
The Journal of Plastination - Ascaris Plastination through S10 Techniques. [Internet]. [Accessed April 22, 2024]. Available from: https://journal.plastination.org/articles/ascaris-plastination-through-s10-techniques/
"Ascaris Plastination through S10 Techniques." The Journal of Plastination [Online]. Available: https://journal.plastination.org/articles/ascaris-plastination-through-s10-techniques/. [Accessed: April 22, 2024]

INTRODUCTION

Infection with Ascaris lumbricoides continues to be a significant health problem throughout the world (Lynne and Garcis, 2001). Ascaris occurs in about 22 percent of the world population (Muller and Baker, 1990). Depending upon poor sanitation for its spread, human Ascarids have been described as a household and backyard infection (Bogitsh and Cheng, 1998). Ascaris is contacted by ingesting mature eggs from contaminated soil which occurs most often among children who play on the ground. Food, mainly vegetables, and drinking water may be  contaminated and become the source of infection (Tsieh, 1999). In educational courses in medical colleges, specimens of Ascaris are utilized for demonstration purposes. The form most widely  used is formalin fixed worms. This approach to teaching has some disadvantages , among the most undesirable are odor and dampness. This investigation was designed  to employ S10 method instead of formalin to produce more desirable teaching specimens. It was assumed that using the S10 plastination technique would produce specimens which are dry, odorless, and preserve the natural shape and appearance of the parasite .

MATERIALS AND METHODS

The Ascarid specimens used in this study had been fixed in 5% formaldehyde for an extended period of time. These specimens were rinsed in cold tap water to remove as much formaldehyde as possible. The specimens  were  subsequently  cooled  to  5°C prior  to dehydration. Several specimens of Ascaris were submerged in at least three baths of one hundred percent acetone at -20°C. The ratio volume of acetone to the specimens approximately was 10:1. The  low temperature fixes the shape of specimens . When the acetone concentration remained at 99%, after approximately three weeks, dehydration was deemed complete. The Ascarids were then submerged in a mixture of S10/ S3 (100:1) for at least one day at -20°C. Longer immersion at this stage serves to shorten the impregnation time for the specimens and also reduces the shrinkage of the worms ' cuticles. The volume ratio of silicone to the specimens was 3: 1. In this stage the specimens immersed in silicone were placed under vacuum for 14 to 18 days at -20°C. The pressure was slowly decreased to 5mm Hg. Ascaris cuticles are somewhat impermeable to large molecules and surrounds a very small visceral space. For this reason, a slow decrease in pressure helps to prevent shrinkage of the specimens (Table 1). After forced impregnation, the Ascarids were removed from the polymer and excess polymer was drained from their surfaces for three days. The specimens were then placed in a single layer on a grid in the Biodur HH, 0 gas curing unit and exposed to S6 gas cure vapors for 3 days at room temperature (von Hagens, 1985).

 
Pressure Time
85mm Hg 1-2 days
75mm Hg 2 days
65mm Hg 1-2 days
55mrn Hg 2 days
45mm Hg 1-2 days
35mm Hg 2 days
25mm Hg 1-2 days
15mm Hg 2 days
5mm Hg 2 days

RESULTS

After plastination, the Ascarid specimens retained their original shapes (Fig. 1). The Ascarids retained some flexibility. The plastinated specimens are odorless, non-toxic and dry to the touch (von Hagens et al., 1987).

Figure 1. Plastinated Ascarid.

DISCUSSION

Plastination of animal and fish are reported in some articles (Asadi,  1998; Zhong et al., 2000), but  in  this research, it was the first trial of plastination in parasitology . Not only were the resulting specimens dry and odorless, but the color of the plastinated worms was more aesthetic than that of specimens stored in formaldehyde. Because of the good results for teaching, it was suggested that in the future that plastination in the teaching of parasitology be considered as an alternative to traditional preservation methods. It should be mentioned that S10 plastination is recommended for considerably large size parasites like Ascaris and Teania and it may not be suitable for smaller nematodes .

REFERENCES

Asadi MH. 1998: Plastination of sturgeons with the S 10 technique in Iran. J Int Soc Plastination 13(1):15-16. Bogitsh BJ, Cheng TC. 1998: Human parasitology. Academic Press, USA , p 369.
https://doi.org/10.56507/XSTD4829

Lynne LS, Garcis S. 2001: Diagnostic medical parasitology: ASM Press, Washington DC, USA, p 266-279.

Muller R, Baker JR. 1990: Medical parasitology. Gower Medical Publishing, USA.

Tsieh S. I999: Parasitic disorders. 2nd ed. Williams & Wilkins, USA, p 239-299.

von Hagens G. 1985: Heidelberg Plastination Folder: Collection of all technical leaflets for plastination. Heidelberg , Germany: Anatomiches Institut 1, Universitat Heidelberg.

von Hagens G, Tiedemann K, Kriz W. 1987: The current potential of plastination. Anat Embryo! 175(4):411-421.
https://doi.org/10.1007/BF00309677

Zhong ZT, Xuegui Y, Ling C, Jingren L. 2000: The History of Plastination in China. J Int Soc Plastination 15(1):25-29.
https://doi.org/10.56507/QSNK3285

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