Multiple osseous metastases of a carotid body tumor in a dog

Metastasis of malignant carotid body tumor to multiple bones was detected in a 13-year-old female Siberian husky dog. Radiographs exhibited an abnormal mass in the retropharyngeal site and osteolytic lesions in the vertebral bodies, spinous process, tibia, and ribs. At necropsy, multiple masses were observed in the bones as well as at the dorsal area of the retropharynx. Histologically, the tumor cells, arranged in sheets and clusters, had eosinophilic finely granular cytoplasm. Immunohistochemistry showed the tumor cells were positive for neuron-specific enolase and synaptophysin. Electron microscopy demonstrated a number of dense membrane-bound granules in the cytoplasm of the tumor cells. Based on these findings, this case was diagnosed as multiple bone metastases of a malignant carotid body tumor. Spinal cord damage induced by the tumor mass was the cause of the hind limb paralysis of the present dog.     

Morphological investigation of carotid body and its arteries in rabbits

The purpose of this study was to determine the morphology of the rabbit carotid body and its artery at the light microscopy level. The carotid body was situated between the internal and external carotid arteries after the bifurcation point of the common carotid artery. The carotid body was usually found to be a single, ovoid tissue mass but, in some cases it consisted of two or three parts. More carotid bodies were supplied by a single carotid body artery (glomic artery) which arose from the common carotid artery or the internal or external carotid arteries near the bifurcation point of the common carotid artery. In only one case were there two arteries which arose from opposite sides of the external carotid artery at its origin. There was a distinguishable sinus (glomic sinus) at the origin of the glomic artery. This artery had a thin wall with elastic laminae in the sinus area which become thinner distal to the sinus.     

Arteries of the Carotid Body in Rats

The arterial blood supply of 40 carotid bodies in 20 Wistar rats of both sexes, aged 10-12 weeks (250-350 g), was examined by light microscopy. The carotid bodies of all rats were supplied by only one carotid body artery. The average diameter of the carotid body arteries was 40 microns. This artery arose either from the external carotid artery (97.5%) or the occipital artery (2.5%). There was an intimal cushion at the origin of the carotid body artery. The carotid body artery, after reaching the caudal pole of the carotid body, divided into the first-order branch. In the carotid body, the paranchyma was divided into the second-order branch. The carotid body artery was of the muscular type.     

ULTRASONOGRAPHIC EXAMINATION OF CERVICAL MASSES IN THE DOG AND CAT

The ultrasonographic appearance of clinically undifferentiated neck masses for which a definitive diagnosis was eventually obtained in nineteen dogs and one cat is presented in this report. Multiple lesions were seen ultrasonographically in 4 dogs and no cervical abnormalities were seen in 2 dogs resulting in 22 lesions in 20 annuals. Of 7 benign lesions, there were 2 patients with reactive lymph nodes from a regional inflammatory process, and 1 patient each with primary pyogranulomatous lymphadenitis, arteriovenous malformation, foreign body granuloma, cellulitis, and hematoma. Of 15 malignant lesions, 7 were thyroid carcinomas, 3 were lymphomas with submandibular and cervical lymph node enlargement, 3 were lymph node enlargements associated with regional metastasis of malignant tumors, one was a leiomyosarcoma and one was a carotid body tumor. One dog with a diffuse soft tissue swelling of the ventral cervical region had only slight asymmetry of the thyroid lobes on ultrasound examination and no abnormalities of the neck at post mortem. A second dog examined with ultrasound 4 months after surgical removal of a carotid body tumor had no evidence of tumor recurrence. Ultrasonographic examination provided information regarding the character of the lesions, the tissue or organ of origin, and invasion into other anatomic structures. Ultrasound examination in conjunction with fine needle or tissue biopsy provided a definitive diagnosis in those animals in which biopsies were performed.     

The Evidence of Carotid Body in the Carotid Rete of the Shiba Goat

The carotid body was found in/on the cavernous sinus of the carotid rete of the Japanese miniature Shiba goat by light and electron microscopies. The carotid body-like aggregated cell group consisted of two types of cells arranged in the lobule. The first type contained membrane-bound granular vesicles; these cells resembled to the type-I cells in the carotid body. The second type contained no cytoplasmic vesicles, and were located in the periphery, investing the type-I cells. These features appear to be consistent with those of the type-II cells in the carotid body. The nerve ending showed two peculiar features in the intercellular space of type-I cells. The clear vesicle-containing nerve ending showed a structural feature indicative of efferent synapsis. The small granular vesicle-containing nerve ending has been described as a baroreceptor-like ending by VERNA (1979). All of these features are typical characteristics of the carotid body.     

Occlusion of the Middle Cerebral Artery: a New Method of Focal Cerebral Ischemia in Rats

The study in Wistar rats attempted to improve the occlusion technique of the middle cerebral artery (MCA) as a precise method for initiating stroke. In a first part it was necessary to study the exact anatomy of blood vessels of the brain in seven rats of 170-410 g body weight by corrosion cast. The lengths and diameters of defined locations of the blood vessels were measured. The temporary as well as the permanent methods were refined or replaced. The first one was completed in main training the physiological blood flow after temporary occlusion, while the permanent occlusion was performed by positioning a silicone cap in the MCA. A filament guide was introduced from the common carotid artery (CCA) via internal carotid artery (ICA) to guide the silicon cap at the branch of the MCA. Histological sections of the brain of rats showed 24 h after the permanent occlusion a reproducible infarct in the brain. This area corresponded very well with the supply of the MCA. The new occlusion method with a silicon cap was compared with the occlusion methods of CCA route and external carotid artery (ECA) route. The total infarct volume was significantly larger in the CCA route and ECA route groups than in the silicon cap group (means: CCA route 261 mm³; ECA route 191 mm³ vs. 128 mm³ silicon cap group; P  < 0,05). It could be demonstrated that the new silicon cap occlusion technique imitates the pathological situation of a cerebral infarct in man. Moreover it is less invasive for the animals and more precise and reproducible regarding the infarcted area in comparison to the other occlusion methods. Based on anatomical measurements of the blood vessels the described silicon cap method can be recommended for rats of a body weight between 340–370 g.     

Paratracheal cervical mass in a dog

A 14-year-old female Welsh Terrier was presented for evaluation of multiple skin masses. Two of them were diagnosed as a follicular (epidermal) cyst and a sebaceous epithelioma by cytology and histopathology. The third mass was located in the subcutis adjacent to the cervical trachea. Clinical findings, thoracic radiography, and laboratory results were otherwise unremarkable. Cytologically, the cervical mass was characterized by the presence of round to polygonal cells with distinct cell borders, mild to moderate anisocytosis, round to oval eccentric nuclei with prominent nucleoli, and a variable amount of finely granular, eosinophilic cytoplasm. Differential diagnoses included endocrine/neuroendocrine tumors such as thyroid adenocarcinoma, medullary thyroid carcinoma, carotid body chemodectoma, and parathyroid carcinoma. The mass was removed surgically and submitted for histopathologic and immunohistochemical examination. Histologically, the mass was composed of rows and nests of densely packed cells separated by thin fibrovascular stroma. Neoplastic cells had moderate to large amounts of pale eosinophilic dusty or finely vacuolated cytoplasm and round to oval nuclei with finely dispersed chromatin and 1 or 2 small nucleoli. On immunohistochemistry, neoplastic cells were positive for chromogranin A, calcitonin, and neuron-specific enolase, and were negative for cytokeratin and thyroglobulin. The final diagnosis was medullary thyroid carcinoma, an uncommon endocrine tumor of dogs that has cytologic and histopathologic features similar to other endocrine and neuroendocrine tumors. Immunohistochemistry or immunocytochemistry should be performed to differentiate medullary thyroid carcinoma from other endocrine/neuroendocrine tumors of dogs.     

Carotid Body Tumors in the Dog Eleven Cases (1978–1988)

Case records of 11 dogs with histologically confirmed carotid body tumors were reviewed. Surgical excision had been attempted in ten dogs with carotid body tumors, and one dog had been euthanatized at diagnosis. There were no intraoperative deaths but perioperative mortality was 40%. Horner's syndrome and laryngeal paralysis were the most common postoperative morbidities. The median survival time after surgery alone in the four dogs that survived the perioperative period was 25.5 months (range, 12-45 months). Two dogs treated with postoperative radiation therapy had survival times of 6 and 27 months. Of the six dogs surviving the perioperative period, two dogs are still alive at 19 and 32 months postoperatively. Of the four dogs that died, one was euthanatized 12 months postoperatively for nontumor-related causes. The remaining three dogs died of distant metastases. The carotid body tumors studied were characterized by local tissue invasion, neurovascular complications after therapy, and a propensity to metastasize to multiple sites in the body.     

PULSED WAVE-DOPPLER ULTRASONOGRAPHIC EVALUATION OF THE COMMON CAROTID ARTERY IN THE RESTING HORSE: PHYSIOLOGIC DATA

A pulsed wave-Doppler ultrasonographic evaluation of common carotid arterial blood flow was carried out on 63 healthy Italian Saddlebred horses. Vessel diameter and tracing morphology were evaluated were evaluated and blood flow parameters (systolic, diastolic and mean velocity, acceleration and deceleration of the systolic wave, cartid pulse volume) were calculated and correlated with class variables (sex, age and body weight). On the basis of the presence of an incisure in the ascending branch of the systolic curve, subjects were divided in two groups: one with a bifid systolic curve and the other with a monophasic aspect. Correlations between: 1) diameter of the vessel and body weight and 2) carotid pulse volume and flow velocity (systolic, diastolic and mean) were found. A greater systolic pulse volume was found in male subjects, in subjects with greater body weight and in those which had a monophasic systolic wave.     

CT AND MRI FEATURES OF CAROTID BODY PARAGANGLIOMAS IN 16 DOGS

Carotid body tumors (paragangliomas) arise from chemoreceptors located at the carotid bifurcation. In imaging studies, this neoplasm may be confused with other neck neoplasms such as thyroid carcinoma. The purpose of this retrospective, cross‐sectional study was to describe computed tomographic (CT) and magnetic resonance imaging (MRI) characteristics of confirmed carotid body tumors in a multi‐institutional sample of dogs. A total of 16 dogs met inclusion criteria (14 examined using CT and two with MRI). The most common reason for imaging was a palpable cervical mass or respiratory signs (i.e., dyspnea or increased respiratory noises). The most commonly affected breed was Boston terrier (n = 5). Dogs were predominantly male castrated (n = 10) and the median age was 9 years [range 3–14.5]. Most tumors appeared as a large mass centered at the carotid bifurcation, with poor margination in six dogs and discrete margins in ten dogs. Masses were iso‐ to hypoattenuating to adjacent muscles in CT images and hyperintense to muscles in T1‐ and T2‐weighted MRI. For both CT and MRI, masses typically showed strong and heterogeneous contrast enhancement. There was invasion into the adjacent structures in 9/16 dogs. In six of these nine dogs, the basilar portion of the skull was affected. The external carotid artery was entrapped in seven dogs. There was invasion into the internal jugular vein in three dogs, and into the external jugular, maxillary, and linguo‐facial veins in one dog. Imaging characteristics helped explain some clinical presentations such as breathing difficulties, Horner's syndrome, head tilt, or facial nerve paralysis.     

兔颈动脉窦和颈动脉体的神经支配

用ＨＲＰ法对兔颈动脉窦和颈动脉体的神经支配进行了分析,表明,支配颈动脉窦和颈动脉体的标记细胞均出现于舌咽神经远节和颈上节。颈动脉体感觉传入中枢突终未见于延髓闩部邻近极后区的腹外侧,颈上节的标记细胞分布于尾侧半部。提示颈动脉窦和颈动脉体对心血在管活动的调节存在着经舌咽神经将感觉传入中枢的通路和经颈上节进行交感神经活动支配的传出通路。为研究心和管生理提供了形态学资料。     

Cardiopulmonary effects of a medetomidine-ketamine combination administered intravenously in gopher tortoises

OBJECTIVE: To determine whether IV administration of a combination of medetomidine and ketamine depresses cardiopulmonary function in healthy adult gopher tortoises. DESIGN: Prospective study. ANIMALS: 3 adult male and 3 adult female nonreleasable gopher tortoises. PROCEDURE: Prior to the study, carotid and jugular catheters were surgically placed in each tortoise for blood collection, direct arterial blood pressure monitoring, and drug administration. Heart rate, direct carotid arterial blood pressure, and body temperature were measured before and every 5 minutes for 45 minutes after IV injection of medetomidine (100 microg/kg [45.5 microg/lb]) and ketamine (5 mg/kg [2.3 mg/lb]). Carotid arterial blood samples were collected before and 5, 15, 30, and 45 minutes after medetomidine-ketamine administration to determine pH, PO2, and PCO2. Atipamezole (500 mg/kg [227 microg/lb], IV) was administered 30 minutes after administration of medetomidine-ketamine. RESULTS: The medetomidine-ketamine combination caused a moderate increase in arterial blood pressure, and moderate hypercapnia and hypoxemia. There were no significant changes in heart rate or body temperature. Intravenous administration of atipamezole rapidly induced severe hypotension. CONCLUSIONS AND CLINICAL RELEVANCE: The combination of medetomidine and ketamine administered IV resulted in effective short-term immobilization adequate for minor diagnostic procedures in gopher tortoises. This combination also caused moderate hypoventilation, and it is recommended that a supplemental source of oxygen or assisted ventilation be provided. Atipamezole administration hastens recovery from chemical immobilization but induces severe hypotension. It is recommended that atipamezole not be administered IV for reversal of medetomidine in tortoises and turtles.     

Effects of fenoldopam on cecal blood flow and mechanical activity in horses

Lateral cecal arterial blood flow, carotid arterial pressure, heart rate, and mechanical activity in the duodenum, right ventral colon, cecal body, and cecal apex were measured in 6 conscious healthy horses for 60 minutes during and for 120 minutes after IV infusion of 0.9% NaCl solution (control) or fenoldopam. There were no significant changes in these measurements during or after infusion of 0.9% NaCl (saline) solution. Fenoldopam, a selective dopamine-1 receptor agonist, was administered in saline solution at dosages of 0.01, 0.05, and 0.1 micrograms/kg/min. Intravenous infusion of fenoldopam at 0.01 microgram/kg/min significantly increased heart rate, but did not change average carotid arterial pressure or lateral cecal arterial blood flow. Intravenous infusion of fenoldopam at both 0.05 and 0.1 microgram/kg/min significantly increased heart rate, significantly decreased average carotid arterial pressure, and significantly increased lateral cecal arterial blood flow. Intravenous infusion of fenoldopam at 0.01, 0.05, and 0.1 microgram/kg/min did not significantly change the mechanical activity measured by the area under the strain gauge deflection curve for the duodenum, right ventral colon, cecal body, or cecal apex. These results suggest that dopaminergic-1 receptors are present on the colonic vasculature of horses. There was no evidence, however, that dopaminergic-1 receptors exist on the visceral smooth muscle of the duodenum, right ventral colon, cecal body, or cecal apex of horses.     

Multiple organ metastasis of an aortic body tumor in a boxer

A 9-year-old sexually intact male Boxer with a history of multiple episodes of syncope and various cardiac arrhythmias was determined radiographically to have a large mass in the heart-base region and was subsequently euthanatized upon worsening of clinical signs. Histologic and ultrastructural examination of tissue from the heart-base mass indicated that the tumor was most likely a chemodectoma derived from the aortic body (aortic body tumor, extra-adrenal paraganglioma). Macroscopic and/or microscopic evidence of metastasis of the tumor was seen in the lungs, myocardium, spleen, liver, kidneys, and dura mater over the cerebellum.     

Lenticular invasion by a ciliary body adenocarcinoma in a dog

Ciliary body adenocarcinomas are well-recognized tumors in dogs; however, invasion of the lens by the tumor has not been described in veterinary species. Evaluation of the right eye of a 10-year-old Labrador Retriever revealed a ciliary body mass spanning from the 10 o'clock to 2 o'clock position that was impinging on the lens. Histologic evaluation of the enucleated eye revealed a ciliary body adenocarcinoma with lens invasion. Where the tumor encroached on the lens, the lens capsule was absent and there was scrolling of the broken ends of the capsule. Tumor cells were juxtaposed to the lens fibers and dissecting between the lens fibers. There were no inflammatory cells within the lens associated with the breaks in the capsule or within the anterior chamber. To our knowledge this is the first report of lens invasion by a tumor in any veterinary species.     

A method for chronically quantifying net absorption of nutrients and gut metabolites into hepatic portal vein in conscious swine

Surgical procedures are described for chronic cannulation of portal vein, ileal vein, abdominal aorta, and carotid artery in pigs. Silastic or Micro-Renathane tubing was used for cannulating portal vein and ileal vein, while carotid artery was cannulated with Micro-Renathane tubing. The lumen of Micro-Renathane tubing was coated with tri-dodecylmethyl ammonium chloride (TDMAC)-heparin complex. The abdominal aorta was cannulated via saphenous artery with vinyl tubing. This allows simultaneous collection of blood samples from hepatic portal vein and systemic artery (carotid or abdominal aorta) and continuous infusion of p-aminohippuric acid (PAH) into ileal vein. The constant PAH infusion provided an indicator-dilution method for estimating the blood flow rate in portal vein. In 13 pigs weighing 54 +/- 2.8 kg, the mean portal vein blood flow rate during the 8-h postprandial period was estimated to be 1,979 ml X min-1 X pig-1 or 37.8 ml X min-1 X kg-1 body weight. By simultaneously measuring the concentration of nutrients and metabolites in the portal and systemic arterial blood and multiplying porto-arterial differences by the estimated portal vein blood flow rate, the net absorption of nutrients (except long-chain fatty acids) and metabolites into hepatic portal system in conscious swine can be quantified.     

Histomorphologic structure of the carotid rete-cavernous sinus complex and its functional importance in sheep (Ovis aries)

Paraffin sections of the carotid rete-cavernous sinus complex of sheep were studied, using different stains. The carotid rete of sheep was composed of medium-sized arteries with smooth muscle layers that were oriented in different directions. The carotid body cells may have migrated proximally in the adventitia of the intracranial portion of the internal carotid artery as its extracranial portion degenerates early in life. The cavernous sinus shared a common tunica adventitia with surrounding rete branches. At places, the wall of the cavernous sinus had a distinct tunica media interposed between the endothelial cells and the tunica adventitia. Therefore, the name cavernous venous plexus has been proposed for the cavernous sinus in sheep.     

Adult Stem Cells: Perspectives for Therapeutic Applications

The right and left cranial cervical ganglia in the heads of 10 adult guinea pigs (5 male, 5 female) were dissected in detail. The cranial cervical ganglion (CCG) was located on the caudo-ventral aspect of the distal ganglion of the vagus nerve, and medial to the digastric and styloglossal muscles. It was present also ventral to the tympanic bulla, ventro-lateral to the longus capitis muscle, and between the ascending pharyngeal and the internal carotid arteries. The branches of the CCG included the internal and external carotid nerves, the jugular nerve and connecting branches to the pharynx, vagus, glossopharyngeal, accessory, cranial laryngeal, first and second cervical nerves, and vessels in the carotid body region. The number of nerves ramifying from the CCG of the guinea pig varied among cases. Compared to other species, there are also differences in the number of nerve branches and the course patterns. No sex differences are present as far as the guinea pig CCG is concerned.     

COMPARISON BETWEEN CLINICAL,ULTRASOUND, CT,MRI, AND PATHOLOGY FINDINGS IN DOGS PRESENTED FOR SUSPECTED THYROID CARCINOMA

This study compares clinical, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and pathology findings in 16 prospectively, and seven retrospectively recruited dogs presented for suspected thyroid carcinoma. Of these, 17 were confirmed thyroid carcinoma, while six were initially misdiagnosed. These included four carotid body tumors, one para‐esophageal abscess, and one undifferentiated squamous cell carcinoma. Thyroid carcinomas occurred in older dogs without evidence of sex predilection, and were more often unilateral. All were large, heterogeneous, moderately to strongly vascularized, and most commonly contained areas of dystrophic mineralization and/or fluid accumulations. On MRI, thyroid carcinomas appeared hyperintense compared to surrounding musculature in all imaging sequences used, while on CT they had a lower attenuation value than normal thyroid gland tissue. Histologically confirmed tumor capsule disruption with invasion of the surrounding structures was most commonly detected with MRI. Palpation was not an accurate predictor of locally invasive vs. well‐encapsulated masses. Computed tomography had the highest specificity (100%) and MRI had the highest sensitivity (93%) in diagnosing thyroid carcinoma, while ultrasound had considerably lower results. We conclude that ultrasound is adequate for use as a screening tool for dogs with suspected thyroid carcinoma, but recommend either CT or MRI for preoperative diagnosis and staging.     

Factors influencing complete tumor excision of mast cell tumors and soft tissue sarcomas: a retrospective study in 100 dogs

The recommended treatment for soft tissue sarcomas (STS) and mast cell tumors (MCT) is complete surgical removal, provided that the tumor is amenable to surgical excision. The objective of this study was to evaluate possible risk factors for incomplete surgical excision of skin and subcutaneous STS and MCT in 100 dogs treated with wide excision with curative intent. Decreased body weight was a risk factor (P = 0.03, odd's ratio = 0.96) as well as increased tumor size (1.4% increase in risk of incomplete excision per cm(2); P = 0.02). Gender, age, breed, location, grade, tumor type, re-excision, and level of surgeon's training (P = 0.0711) were not significant. Veterinary surgery residents were at increased risk of incompleteness of excision compared with ACVS surgeons and ACVS surgeons with additional training in surgical oncology.