Noninvasive Monitoring of Radiation-Induced Salivary Gland Vascular Injury.

Xerostomia is a common side effect of radiation therapy (RT) in patients with head and neck cancer. However, limited information is available on the temporal dynamics of parenchymal and vascular changes in salivary glands following RT. To address this gap in knowledge, we conducted experimental studies in mice employing ultrasound (US) with coregistered photoacoustic imaging (PAI) to noninvasively assess the early and late changes in salivary gland size, structure, vascularity, and oxygenation dynamics following RT. Multiparametric US-PAI of salivary glands was performed in immune-deficient and immune-competent mice before and after RT along with correlative sialometry and ex vivo histologic-immunohistochemical validation. US revealed reduction in gland volume and an early increase in vascular resistance postradiation. This was accompanied by a reduction in glandular oxygen consumption on PAI. Imaging data correlated strongly with salivary secretion and histologic evidence of acinar damage. The magnitude and kinetics of radiation response were impacted by host immune status, with immunodeficient mice showing early and more pronounced vascular injury and DNA damage response compared to immunocompetent animals. Our findings demonstrate the ability of noninvasive US-PAI to monitor dynamic changes in salivary gland hemodynamics following radiation and highlight the impact of the host immune status on salivary gland radiation injury.

Impact of Age on Disease Progression and Microenvironment in Oral Cancer.

Despite the recognized link between aging and cancer, most preclinical studies in experimental tumor models are conducted with 6- to 8-wk-old rodents. The goal of the present study was to examine the impact of age on tumor incidence, growth, and microenvironmental characteristics in mouse models of head and neck squamous cell carcinoma (HNSCC). Experimental studies were conducted with the 4-nitroquinoline-oxide (4NQO) oral carcinogenesis model and orthotopic FaDu HNSCC xenografts, established in young (7 to 12 wk of age) and old (65 to 70 wk of age) female C57BL/6 mice ( n = 44; 4NQO model) and severe combined immunodeficient mice ( n = 13; HNSCC xenografts). Noninvasive whole body magnetic resonance imaging revealed increased subcutaneous and visceral fat in aging animals of both strains. On histologic examination, a higher incidence ( P < 0.001) of severe dysplasia/invasive squamous cell carcinoma was observed in old mice (92%) as compared with young mice (69%). Old C57BL/6 mice exposed to 4NQO exhibited increased incidence of oral and extraoral (peritoneal masses) neoplasms (42%) versus their young counterparts ( P < 0.05). The incidence of extraoral neoplasms was significantly lower (16%) in the younger cohort. Interestingly, no difference in growth rate and oxygen saturation was observed between orthotopic FaDu xenografts established in old and young severe combined immunodeficient mice. Our observations suggest that host age may have an impact on the growth kinetics and progression of HNSCC in the immunocompetent 4NQO model. Further investigation into the impact of aging on tumor response to preventive and therapeutic intervention is warranted.

Suspected ehrlichial infection in five cats from a household.

Ehrlichiosis is a poorly recognized condition of cats that may be associated with anemia, leukopenia, thrombocytopenia, or dysproteinemia. Affected cats may have indirect fluorescent antibody titers to Ehrlichia canis and E risticii. We reviewed the clinical evaluation and response to treatment of 5 cats in a household where ehrlichial disease was suspected as the cause of recurrent leukopenias and thrombocytopenias. All of the cats had E risticii indirect fluorescent antibody titers and western blot confirmation of antibodies to 4 of the 9 major antigens of E risticii. Response to doxycycline was monitored serologically and hematologically in each cat, and indicated that administration of doxycycline at a dosage of 10 mg/kg of body weight, PO, every 12 hours, for a minimum of 21 days is necessary for treatment of this condition.

Pulmonary tuberculosis in a sulfur-crested cockatoo.

An adult, female sulfur-crested cockatoo (Kakatoe sp) was examined because of dyspnea associated with hemoptysis. On radiographic examination there was a large cystic pulmonary mass that, on aspiration, was found to contain thick sanguineous fluid. Ziehl-Neelsen staining of aspirate smears revealed numerous acid-fast organisms. Gross necropsy and microscopic findings suggested a diagnosis of tuberculosis, with primary focus of infection in the pulmonary tissues. Bacteriologic isolation and typing confirmed a diagnosis of tuberculosis and established Mycobacterium avium as the etiologic agent.

Urethral obstruction in male cats: transmission studies.

Urethral obstruction was produced by injecting centrifuged urine from cats with urethral obstruction into the urinary bladders of unaffected cats. Filtration of urine from affected cats did not remove the causative factor.