Biology - Syrian Hamster Flashcards
What is a unique feature of M. auratus pups?
Incisor teeth are visible at birth.
At what age do M. auratus ears open, hair growth observed, and eyes open?
Ears: 4-5 days
Hair growth: 9 days
Eyes: 14-16 days
When are M. auratus sexually mature?
6-8 weeks to 14 months.
What is the lifespan of M. auratus? Is there a sex influence?
Averages 2 years, up to 3 years. Females may live shorter based on strain and source.
What gestation day in M. auratus is optimal for studying fetal development?
Day 8 - Hourly development of fetal pup can be observed.
Describe the cheek pouches of M. auratus.
Bilateral invaginations of the oral mucosa, found in the lateral buccal walls. Often used for storage of food and bedding. Do not contains glands. Highly vascular, rich in mast cells, and lined with stratified squamous epithelium. Blood flow supplied from external carotid artery.
Why are the cheek pouches described as immunologically privileged? What does this enable?
Pouches lack intact lymphatic drainage and surface density of Langherans cells is markedly decreased. Supports lock-term survival of transplanted foreign tissue w/o rejection - evaluation of human cancer development.
Why are Syrian hamsters prone to developing caries? What conditions are required? What factors impact caries development?
Due to morphological makeup of their crown teeth, retention of fine food particles often occurs. Defined diet and oral flora. Amount of carbohydrates, form of carbohydrates, presence/absence of vitamins in diet, and transmissible infectious bacteria
What compartments does a hamster’s stomach have? What are the functions of each?
Glandular stomach and nonglandular forestomach. Nonglandular forestomach similar to that of ruminant - Has an elevated pH and microflora that contribute to digestion through fermentation.
The experimental induction of papillomas and adenocaricnomas in the forestomach and intestines and adenomatous polyps in the colon validates what model?
Hamster model of gastrointestinal carcinogenesis
Why was the hamster historically used to study pharmacologic agents that inhibit intestinal fluid secretion?
Syrian hamsters respond predictably to intragastric administration of purified enterotoxin with intraluminal accumulation of fluid in small bowel, cecum, and proximal colon.
How does the major pancreatic duct and common bile duct enter the duodenum? How does this compare to other species?
Major pancreatic duct joins common bile duct shortly before it enters the duodenum. Similar to mice and rats, distinct from other mammals.
How can the pancreatic cancer be induced in hamsters?
Subcutaneous administration of nitrosamines or implantation of transplantable cell line PGHAM-1
What feature in hamsters facilitates modeling of chronic bronchitis? Centrilobular emphysema? Pulmonary carcinogenesis?
Limited number of glandular structures, primarily in proximal trachea.
Similar pulmonary vascular bed with lesions developing when exposed to intratracheal porcine pancreatic elastase.
Spontaneous bronchiogenic and pulmonary cancers rare
Why does administration of estrogens to male hamsters lead to renal tumors?
Reproductive and urogenital tracts develop from same embyronic germinal ridge, rendering kidneys responsive to estrogen.
Why are adrenal glands larger in size in male hamsters?
Greater number of reticular cells in adrenal cortex
Describe skin allografts in hamsters.
Do not reject skin allografts to same extent as rejection by other species.
What immunoglobulin do hamsters lack? What component of complement do some strains of hamsters lack? What unique IgG isotype has been identified in some inbred hamsters?
IgD. 6th. IgG3 - Affinity for protein A
What is the function of the harderian gland of hamsters? Describe the sexual dimorphism in Syrian hamsters.
Lipid- and porphyrin-rich material that lubricates eyes and eyelids, immune response, thermoregulatory lipids and pheromones, photoprotective organ, part of retinal-pineal axis. Females secrete up to 10^3 times more porphyrin than males. Dimorphism is androgen-dependent and exhibits seasonal variation.
Describe flank glands in hamsters.
Coarse hair over darkly pigmented skin in the costovertebral area in males. Dermal structures composed of sebaceous glands that produce secretions in response to androgens. When sexually excited, hair over glands becomes wet and male may appear pruritic. Used for territorial marking. Females also possess, less easily identifiable and secretions associated with estrous cycle.
At what temperature will Syrian hamsters hibernate?
Approx. 5C, +/- 2C.
Why is the Syrian not used extensively for hibernation studies? What aspects of hibernation physiology are specifically studied?
May not reliably enter hibernation when exposed to cold temps and bouts of hibernation may be short. Factors controlling the saturation of fat, as cold weather/hibernation are associated with desaturation of white adipose tissue.
