Squamous cell carcinoma with metastasis in a cynomolgus monkey (Macaca fascicularis)

A squamous cell carcinoma of the vulva with metastases to the inguinal lymph nodes and lung occurred in a female cynomolgus monkey (Maccaca fascicularis). The primary tumor was a pedunculated mass at the mucocutaneous junction of the left labium anterior to the clitoris.     

Conjoined twins in a rhesus monkey (Macaca mulatta)

Conjoined twinning is an extremely rare occurrence among human and nonhuman primates. The current report describes a case of minimally conjoined omphalopagus rhesus monkey twins that were observed in the breeding colony at the California Regional Primate Research Center. The full-term nonviable male twins were morphologically normal and united in the umbilical region, involving the liver, xiphoid, umbilicus, body wall, and skin. The umbilical cords were separate, but closely aligned, within an ensheathing amnion; each cord contained two arteries and a vein. The closely associated cords were centrally inserted on a large bidiscoid placenta. There were no gross or histologic abnormalities in the viscera, with the exception of enlargement of the left central liver lobes, which constituted the area of attachment. The cause of death was attributed to asphyxia and trauma experienced during parturition.     

Alopecia areata in a rhesus monkey (Macaca mulatta)

BACKGROUND: A 14-year-old female rhesus monkey (Macaca mulatta) of Chinese origin has been suffering from alopecia universalis since childhood. METHODS: Recently, the health status of the animal was recorded comprehensively by detailed clinical examination including hematology and serology supplemented by histological and immunohistochemical investigations of skin biopsies and molecular biological techniques to clarify the causes of the persistent hair loss. RESULTS AND CONCLUSIONS: The hairless gene (hr) nonsense mutation was ruled out by polymerase chain reaction and by sequencing of the corresponding gene. Histological examinations revealed a prominent chronic lymphocytic perifolliculitis and folliculitis affecting anagen stage hair follicles as well as miniaturized hair follicles. Immunohistochemistry using the antibodies CD3, CD20 and CD4 confirmed the diagnosis of a T-cell-mediated autoimmune disease resembling alopecia areata universalis in humans.     

Arteriovenous malformation in a rhesus monkey (Macaca mulatta)

A developmental arteriovenous malformation of the right arm was recognized in a 1-year-old rhesus monkey. The diagnosis was based on physical findings, ultrasound, and angiography. Treatment consisting of therapeutic transcatheter embolization using polyvinyl alcohol was performed with partial success. Necropsy revealed a lesion that was limited to the skin and subcutis. An abnormal vascular pattern was present leading to and within the lesion.     

Spontaneous malignant histiocytoma with metastasis in a rhesus monkey [Macaca mulatta].

A malignant histiocytoma was observed on the left arm of a recently imported rhesus monkey. Rapid invasion of deep tissues and tumor growth on the face prompted euthanasia. Necropsy revealed additional neoplastic foci in the lungs, diaphragm, intercostal muscles, pericardium and liver. Microscopically the predominant cell type was histiocytic; some cells had a distinct epithelioid appearance and other were spindle-shaped.     

Persistent truncus arteriosus in a rhesus monkey (Macaca mulatta)

A 47-day-old female rhesus macaque (Macaca mulatta) was examined because of a severe holosystolic heart murmur (grade 5/6) and signs of congestive heart failure. Results of physical examination, thoracic radiography, and cardiac ultrasonography confirmed an advanced stage of congestive heart failure. Due to the animal's age and clinical signs of disease, a congenital heart defect was suspected. Necropsy revealed a rare congenital heart defect known as persistent (common) truncus arteriosus.     

Sebaceous gland adenoma in a rhesus monkey (Macaca mulatta)

A tumor mass was identified below the shoulder region of a 5-year-old male rhesus monkey (Macaca mulatta). The mass was excised and diagnosed as sebaceous gland adenoma based on the microscopic findings. Morphologically it appeared as an elevated, dome-shaped, circumscribed mass of 3.6 x 2.8 x 3.2 cm in dimension with tan speckled color. Histologically, the tumor was composed of mature, sebaceous cells (sebocytes), basal cells arranged in a mass of irregular shapes and sizes, with a characteristic appearance of poly or multilobular structure. Sebocytes were well differentiated with foamy cytoplasm in the center of the lobules and poorly or undifferentiated densely staining basal cells in the periphery of the lobules. Cellular changes in the adjacent lymph node included hyperplasia of plasma cells, macrophages and lymphoid elements with typical mitosis.     

Juvenile rheumatoid arthritis in a rhesus monkey (Macaca mulatta)

A juvenile rhesus macaque (Macaca mulatta) developed a symmetrical erosive polyarthritis involving both large and small diarthrodial joints. Neither an infectious nor a metabolic etiology could be determined. This case shares many clinical and pathological features with the polyarticular form of human juvenile rheumatoid arthritis.     

Adenoviral hepatitis in a SIV-infected rhesus monkey (Macaca mulatta)

BACKGROUND: A 5-year-old female rhesus monkey infected with simian immunodeficiency virus became clinically suspicious with anorexia, increasing weakness and apathy eighty-five weeks after the tonsillar virus inoculation and was euthanised due to a poor prognosis. METHODS AND RESULTS: Postmortal examinations revealed a severe multifocal to coalescing necotizing hepatitis with numerous intranuclear basophilic inclusion bodies. Transmission electron microscopy of the liver resulted in the finding of adenovirus like particles arranged in paracrystalline arrays within the nuclei of hepatocytes.CONCLUSION: The SIV infected rhesus monkey suffered from an adenovirus included necortizing hepatitis, an extremely rare organ manifestation of adenovirus infection in nonhuman primates.     

Mandibular growth in the rhesus monkey (Macaca mulatta)

Mandibular growth of 42 rhesus monkeys (Macaca mulatta) was analyzed quantitatively and qualitatively. Four groups of animals were defined according to dentitional age (i.e., infant, juvenile, adolescent, young adult). At each age growth was observed for a 24 week period. Since some animals were observed at more than one stage of development, 57 periods of growth were studied. The growth incremental data were collected by superimposing serial cephalograms on mandibular implants. Growth and remodeling of both the skeletal and dento-alveolar components of the rhesus mandible were greatest in the infant monkeys and were less in successive age groups. Posterior relocation of the ramus was noted in all age groups while bone deposition on the anterior and inferior borders of the mandibular body was greatest in the younger animals. The most pronounced dental changes also occurred in the younger animals while the dentitions of the adolescent and adult animals were generally more stable. This study demonstrates that the rate and direction of normal mandibular growth varies with the age of the animal. Furthermore, mandibular growth is quantified at four defined maturational levels to provide a set of values illustrating normal mandibular growth. These values can also be used as control data for experimental studies.     

Naturally occurring melioidosis in a colonized rhesus monkey (Macaca mulatta)

An aged wild-caught male rhesus monkey (Macaca mulatta), maintained in a research facility for 10 years, developed bilateral pelvic limb paralysis without other signs of disease. Unresponsive to therapy, the monkey was killed and necropsied. Chronic inflammation with osteolysis of thoracic vertebrae 10-13 was observed. Pseudomonas pseudomallei was cultured and identified from cerebrospinal fluid obtained at the site of the thoracic lesion. This Gram-negative bacterium can cause infection in animals and man and may remain latent for years before the appearance of clinical signs.     

Menetrier's disease in a rhesus monkey (Macaca mulatta).

Gross and microscopic features closely resembling those found in Menetrier's disease in man are described in a 20-month-old rhesus monkey. The gastric lining was characterized by greatly enlarged rugae caused by mucosal hypertrophy and hyperplasia along with outfolding of the muscularis mucosa and the submucosa. The mucosa and submucosa were infiltrated with inflammatory cells, mainly lymphocytes and plasma cells.     

Seasonal influences on rhesus monkey (Macaca mulatta) behavior

Seasonal differences in the behavior of 2.5- to 4.5-year-old female subjects and male subjects >2.5 years of age were studied in two rhesus monkey groups over a period of 6 years. The frequencies and durations of sexual acts and states were higher during the Fall in Georgia, USA, but were significant only with regard to female partners. Total time in social proximity, scores for proximity by partner without social interaction, nonspecific contact, grooming received, and noncontact forms of aggression with female partners were also higher in the Fall. Although more submission and agonistically ambiguous responses were received from female partners during the Fall, no seasonal pattern prevailed for responses performed. More contact aggression was directed to males in the Spring, and the pattern of agonistic behavior observed cannot be accounted for by males fighting over estrous females. Significantly more play was observed among subjects in the Fall, but the oldest males played more in the Spring. Some patterns, like huddling, were seen more in the Fall, but they may have been due to temperature differences. Seasonal differences in morphology and behavior cannot be attributed to a single variable, like temperature, level of gonadal hormones, or sexual competition, and may reflect a broader adaptation to seasonal variables.     

Studies of rhesus monkey (Macaca mulatta) hemoglobin.

One hemaglobin was found in the adult rhesus monkey (Macaca mulatta) by the technique of isoelectric focusing. In addition to the adult hemoglobin, one fetal hemaglobin was observed in neonates of the same species. The alpha and non-alpha globins of rhesus monkey hemoglobins showed similar electrophoretic mobilities as those of human hemoglobin A by cellulose acetate membrane electrophoresis. It appeared that the rhesus monkey hemoglobin system is a good model system for the study of human hemoglobin development.     

Corneal biometrics of the rhesus monkey (Macaca mulatta)

Keratometry, retinoscopy, horizontal diameter, and pachymetry were measured in adult and infant rhesus monkeys (Macaca mulatta). The adult monkeys had a mean corneal thickness of 0.47 +/- 0.03 mm (+/- standard deviation), corneal diameters of 10.6 +/- 0.5 mm, keratometry values of 51.90 +/- 1.61 diopters, and subjective refractions of 0.48 +/- 2.36 diopters. Female adult monkeys had smaller corneal diameters by 0.06 mm (P = .02) and steeper corneas by 0.77 diopters (P = .04). Infant female monkeys also had steeper corneas by 2.37 diopters (P = .05). No significant differences were found between right and left eyes in either adult or infant monkeys.