(Bursey 1977; Clare et al. 1990). Pluripotent cells called plasmatocytes appear to be responsible for the regeneration of tissues, like telsons, in very young animals (Clare et al. 1990).
Krasner et al. examined various suture materials (nylon, polyglecaprone, polydioxanone, polyglycolic acid, and silk) in the telson ligament of horseshoe crabs and found that monofilament nylon produced the least amount of tissue reaction, but none of the materials were superior with regards to holding, and none of the wounds dehisced.
Insects
This is by far the largest group of invertebrates at nearly 1 million described species and possibly the most economically important. Insects are loved and despised worldwide and occupy nearly all niches, except the marine environment. They are important as a human food source in parts of the world and both sustain and destroy agricultural crops, depending on the species of insect and plant. For these reasons, they have been well studied with regards to diseases and pathology (Boucias and Pendland 1999; Cooper 2012). Probably no species has been more thoroughly studied than the domestic honeybee, Apis mellifera (Vidal‐Naquet 2012, 2015). Despite this, virtually nothing traditionally considered surgery, has been published for insects. As with other invertebrates, a fair amount of literature exists describing techniques and procedures where insects are utilized for research and modeling purposes. A 1985 study (Endo et al. 1985) describes “etherized larvae fixed on wooden beds with threads” followed by bisection of the brain and removal of the right lobe. This technique was part of a photoperiod study.
For microsurgery, vibrating glass stylets have been used with insects (Gödde 1989). This technique is primarily used to produce very small lesions (to 0.1 μm) on various insect tissues.
Another area of increasing interest and work is hybrid insect robots (Sanchez et al. 2015). Researchers insert tiny electrodes into various neural ganglia in order to stimulate roach behaviors (Figure 4.10). While this is not veterinary surgery in the strictest sense, it does require skill, experience, and, in some cases, surgical dissection through tissue.
Figure 4.10 This cockroach (Blaberus discoidalis) has been outfitted with a battery‐powered pack and two electrodes entering its pronotal area and inserting into the prothoracic ganglion. This roach/robot hybrid could be controlled remotely to change direction.
Source: Sanchez et al. 2015.
Echinoderms
This interesting and diverse group of about 7000 species includes the sea stars, brittle stars, sea cucumbers, sea urchins, sea biscuits, and crinoids. All are marine, and many are commonly displayed in aquaria and used in research. Humans do not consume most species, but the gonads of sea urchins are a popular food item in some sushi restaurants. This is the first group of invertebrates classified as deuterostomes (embryonically the anus is formed by the blastopore). In all of the previous taxa of this chapter, the blastopore forms the mouth. All chordates, including vertebrates, are deuterostomes (Ruppert et al. 2004). Some species have regenerative capabilities and generally heal well and quickly. Published surgical techniques focus on studies in regeneration and reviews of echinoderm regeneration adequately summarize the topic (Candia Carnevali and Bonasoro 2001; Candia Carnevali 2006). Candia Carnevali and Bonasoro (2001) introduce an entire journal issue (Microscopy Research and Technique) dedicated to the topic. Crinoids (feather stars) are particularly adept at regenerating arms and, in some cases, nearly the entire body (Candia Carnevali et al. 1996, 1998). Some sand dollars, sea cucumbers, and sea urchins are even able to clone themselves (Eaves and Palmer 2003).
Urochordates
This group of invertebrates is closely related to vertebrates in that members have a nerve cord during embryologic development (Ruppert et al. 2004). They are commonly known as sea squirts and can be found on pilings, dock supports, boat hulls, and the ocean floor. In a study examining regeneration in a colonial species, researchers used razor blades and needles to remove individual buds and zoids from the colony (Brown et al. 2009). The authors found that circulating stem cells are responsible for the complex multi‐tissue zoid regeneration.
References
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