The occult primary is a problem well known to head and neck surgeons. Less frequently discussed, but well documented, is cystic degeneration of metastatic nodes. When these conditions combine, they can suggest tumor arising in a pre-existing cervical cyst. This is a controversial condition, rare if it occurs at all, and is not to be invoked lightly.

Chitin is a universal biopolymer that is found in microbes, plants, fungi, the exoskeleton of insects, various species of algae, and bottom-feeding crustaceans. This (1–4)-linked N-acetyl-ß-D-glucosamine polysaccharide can be readily processed with simple chemical procedures without putting a species at risk. Chitin has garnered interest as an alternative substance that can be used in the medical, environmental, and agricultural sectors. Indeed, chitin′s unique nature of biocompatibility, being environmentally safe, and having innate water-solubility allows the polymer to be used in a wide range of applications. In this review, we discuss the possible applications of chitin in the medical, environmental, and agricultural sectors through an extensive search of the latest literature. Moreover, the following review summarizes and explores the new and current studies surrounding the practical uses of chitin to solve issues that are commonly induced by various chemicals which are invasive to the surrounding environment and species co-existing in that area.

Through recent decades, the subtherapeutic use of antibiotics within agriculture has led to the widespread development of antimicrobial resistance. This problem not only impacts the productivity and sustainability of current agriculture but also has the potential to transfer antimicrobial resistance to human pathogens via the food supply chain. An increasingly popular alternative to antibiotics is bacteriophages to control bacterial diseases. Their unique bactericidal properties make them an ideal alternative to antibiotics, as many countries begin to restrict the usage of antibiotics in agriculture. This review analyses recent evidence from within the past decade on the efficacy of phage therapy on common foodborne pathogens, namely, Escherica coli, Staphylococcus aureus, Salmonella spp., and Campylobacter jejuni. This paper highlights the benefits and challenges of phage therapy and reveals the potential for phages to control bacterial populations both in food processing and livestock and the possibility for phages to replace subtherapeutic usage of antibiotics in the agriculture sector.

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