Focused post mortem dissection technique for harvest of rete mirabile in domestic swine (Sus scrofa).

BACKGROUND: Rete mirabile (RM) of the domestic pig is a popular animal model of arteriovenous malformations. The RM (Latin for 'wonderful net)' comprises the arterioarterial portal connecting ascending pharyngeal arteries and the internal carotid arteries, which exists in the skull base of even-toed ungulates. Although angiographic access of the RM is relatively easy, its post mortem procurement is complicated and its detailed technique has not been well described. OBJECTIVE: To present our focused post mortem dissection technique for undamaged and complete harvest of the RM. MATERIALS AND METHODS: Fourteen domestic (40-70 lb (18-32 kg)) swine were used in this study. Angiographies were performed under general anesthesia in all animals. A 5F Berenstein catheter was used for angiography and a 014 microcatheter was used to obtain superselective angiography. A stepwise surgical dissection technique has been developed to efficiently harvest RM. Angiographic and surgical anatomy were also compared. RESULTS: The RM was supplied by bilateral ascending pharyngeal arteries. Bilateral anterior cerebral arteries, middle cerebral arteries, and the basilar system were identified rostral to the RM. Our surgical dissection technique was developed during a project to streamline harvesting of the RM and a stepwise description is as follows: (1) decapitate the swine by removing the head through the plane of the occiput and C1 vertebral body; (2) remove the tongue and oropharynx via a ventral approach; (3) dissect through the posterior pharyngeal wall identifying bilateral tympanic bullae and the basisphenoid bone; and (4) remove the basisphenoid bone about one and half inches above the rostral end of the tympanic bullae to fully expose the rete. CONCLUSIONS: The RM can be procured efficiently and effectively with our technique, without requiring any sophisticated surgical devices.

Cavernosal nerve functionality evaluation after magnetic resonance imaging-guided transurethral ultrasound treatment of the prostate.

AIM: To evaluate the feasibility of using therapeutic ultrasound as an alternative treatment option for organ-confined prostate cancer. METHODS: In this study, a trans-urethral therapeutic ultrasound applicator in combination with 3T magnetic resonance imaging (MRI) guidance was used for real-time multi-planar MRI-based temperature monitoring and temperature feedback control of prostatic tissue thermal ablation in vivo. We evaluated the feasibility and safety of MRI-guided trans-urethral ultrasound to effectively and accurately ablate prostate tissue while minimizing the damage to surrounding tissues in eight canine prostates. MRI was used to plan sonications, monitor temperature changes during therapy, and to evaluate treatment outcome. Real-time temperature and thermal dose maps were calculated using the proton resonance frequency shift technique and were displayed as two-dimensional color-coded overlays on top of the anatomical images. After ultrasound treatment, an evaluation of the integrity of cavernosal nerves was performed during prostatectomy with a nerve stimulator that measured tumescence response quantitatively and indicated intact cavernous nerve functionality. Planned sonication volumes were visually correlated to MRI ablation volumes and corresponding histo-pathological sections after prostatectomy. RESULTS: A total of 16 sonications were performed in 8 canines. MR images acquired before ultrasound treatment were used to localize the prostate and to prescribe sonication targets in all canines. Temperature elevations corresponded within 1 degree of the targeted sonication angle, as well as with the width and length of the active transducer elements. The ultrasound treatment procedures were automatically interrupted when the temperature in the target zone reached 56 °C. In all canines erectile responses were evaluated with a cavernous nerve stimulator post-treatment and showed a tumescence response after stimulation with an electric current. These results indicated intact cavernous nerve functionality. In all specimens, regions of thermal ablation were limited to areas within the prostate capsule and no damage was observed in periprostatic tissues. Additionally, a visual analysis of the ablation zones on contrast-enhanced MR images acquired post ultrasound treatment correlated excellent with the ablation zones on thermal dose maps. All of the ablation zones received a consensus score of 3 (excellent) for the location and size of the correlation between the histologic ablation zone and MRI based ablation zone. During the prostatectomy and histologic examination, no damage was noted in the bladder or rectum. CONCLUSION: Trans-urethral ultrasound treatment of the prostate with MRI guidance has potential to safely, reliably, and accurately ablate prostatic regions, while minimizing the morbidities associated with conventional whole-gland resection or therapy.

Feasibility of a novel system for intraductal balloon-anchored direct peroral cholangioscopy and endotherapy with an ultraslim endoscope (with videos).

BACKGROUND: Advantages of direct peroral cholangioscopy (DPOCS) by using an ultraslim endoscope include a single-operator platform, image quality equal to that of standard endoscopy, and separate water and air channels. However, DPOCS has significant limitations, including cumbersome biliary access, en-face position with the ampulla, and gastric looping of the endoscope. A newly designed anchoring balloon may overcome these challenges. OBJECTIVE: To report the feasibility of DPOCS with the anchoring balloon. DESIGN: Pilot study, porcine model. SETTING: Animal resources center. INTERVENTION: The anchoring balloon system developed by Cook Medical (Winston-Salem, NC) was used for DPOCS. MAIN OUTCOME MEASUREMENTS: Primary: Feasibility of biliary access maintenance and intraductal mobility. Secondary: Feasibility of intraductal therapeutic procedures. RESULTS: Four animal subjects underwent DPOCS with the anchoring balloon. Ductal access was achieved with sphincterotomy in 2 subjects and with a balloon sphincteroplasty in 2 subjects. Intraductal placement of the ultraslim endoscope was achieved in all biliary access attempts without balloon migration or deflation. Common bile duct, cystic duct, bifurcation, and main right and left duct direct visualization was achieved in all cases. Therapeutic interventions by DPOCS, including intraductal biopsy, balloon dilatation, and intraductal bilateral metal stent placement, were all completed successfully. Biliary perforation occurred in one case because of balloon overinflation and in a second case because of sphincterotomy. LIMITATIONS: Prototype study in an animal model and small study size. CONCLUSION: Our results show that the novel anchoring balloon system successfully and safely enables DPOCS for both diagnostic and therapeutic interventions. If corroborated in human trials, it could offer a new platform for biliary interventions.

Electron paramagnetic resonance oxygen imaging of a rabbit tumor using localized spin probe delivery.

PURPOSE: Application of in vivo electron paramagnetic resonance (EPR) oxygen imaging (EPROI) to tumors larger than those of mice requires development of both instrumental and medical aspects of imaging. METHODS: 250 MHz EPR oxygen imaging was performed using a loop-gap resonator with a volume exceeding 100 cm3. The paramagnetic spin probe was injected directly into the femoral artery feeding the rabbit leg/tumor. RESULTS: The authors present continuous wave and electron spin echo EPR oxygen images of a large size (4 cm) VX-2 tumor located on the leg of a New Zealand white rabbit. CONCLUSIONS: This study demonstrates the feasibility of continuous wave and electron spin echo oxygen imaging modalities for investigation of volumes of tumor and normal tissue relevant to large animals. The injection of the spin probe directly into the artery feeding a rabbit leg will allow one to reduce, by over one order of magnitude, the amount of spin probe used as compared to whole animal i.v. injection.

Comparison of thyroidectomized calf serum and stripped serum for the study of thyroid hormone action in human skin fibroblasts in vitro.

BACKGROUND: Knowledge on the action of thyroid hormone (TH) is augmented by the study of tissue responses to TH in vitro. In order to support the growth of cells in vitro, calf serum (CS) is usually added to the medium to provide necessary nutrients and growth factors. However, the content of endogenous TH in the CS may obfuscate changes with small doses of TH. We therefore compared the use of TH-depleted medium, either by resin treatment (stripped-CS) or by the use of CS from a thyroidectomized calf (TxCS) for gene expression studies. METHODS: We describe the method for preparing a thyroidectomized calf, harvesting the blood and preparing the serum. We utilized methimazole in conjunction with the thyroidectomy to prevent TH synthesis in the event of regrowth of the thyroid remnant. RESULTS: Total triiodothyronine (T(3)) and thyroxine concentrations in TxCS were low at <30 ng/dL and <1 microg/dL, respectively. We compared the effect of T(3) on basic transcription element-binding protein (BTEB)1 and stanniocalcin (STC)-1 mRNA expression in human fibroblasts from a normal individual and a subject with resistance to TH (RTH) cultured in stripped-CS to TxCS and demonstrated that with stripped-CS and TxCS differences in the BTEB1 and STC-1 expression of normal and RTH fibroblasts could be detected. CONCLUSIONS: Both stripped-CS and TxCS are suitable to detect subtle differences in TH responsiveness between normal and RTH human skin fibroblasts, yet TxCS is not as costly as stripped-CS and relatively easy to prepare.

Comparison of external catheters with subcutaneous vascular access ports for chronic vascular access in a porcine model.

We sought to compare the outcomes of two chronic vascular access techniques, the externalized catheter and the subcutaneous vascular access port, in pigs. Female farm pigs (n = 30) underwent placement of a chronic vascular access device in the jugular vein for a research protocol: 18 of the animals underwent placement of a tunneled Hickman catheter (THC), and the remaining 12 animals underwent placement of a subcutaneous vascular access port (VAP) without external components. After placement of the devices, animals underwent serial blood sampling. All animals were given identical antibiotic prophylaxis. VAP access required the use of a restraint sling for Huber needle insertion, whereas THC access required no additional equipment. Animals were euthanatized 1 month after placement of the device. In the VAP group, the port was retrieved, cleaned, and steam-autoclaved for reuse. In the THC group, 13 (72%) animals developed infectious complications, and blood and wound cultures were often polymicrobial. One animal was euthanatized secondary to overwhelming sepsis. In addition, three (17%) animals developed thromboembolic complications. In contrast, no thromboembolic complications were noted in the VAP group, and only one animal developed a transient fever which resolved spontaneously; no septic complications or abscesses developed. Blood draws with no anesthesia were successful in both groups. We conclude that subcutaneous vascular access ports are a safe and efficient method for obtaining reliable chronic vascular access for a 1-month period in pigs. The subcutaneous devices were associated with low morbidity. In contrast, externalized catheters can be associated with considerable morbidity.

Induced hypothermia by central venous infusion: saline ice slurry versus chilled saline.

OBJECTIVE: Surface cooling improves outcome in selected comatose survivors of cardiac arrest. Internal cooling with considerable volumes of intravenous cold saline may accelerate hypothermia induction. This study compares core temperatures in swine after central catheter infusions of saline ice slurry (saline with smoothed 100-microm-size ice particles) vs. an equal volume of chilled saline. We hypothesized that slurry would achieve core hypothermia (32-34 degrees C) more consistently and at a faster rate. DESIGN: A total of 11 swine were randomized to receive microparticulate ice slurry, chilled saline infusion, or anesthesia alone in a monitored laboratory setting. INTERVENTIONS: Intravenous bolus (50 mL/kg) of slurry or chilled 1.5% NaCl saline. Slurry was composed of a 1:1 mixture of ice and distilled H2O plus NaCl. MEASUREMENTS: Cerebral cortex, tympanic membrane, inferior vena cava, rectal temperatures, electrocardiogram, arterial blood pressure, and arterial oxygen saturation were recorded for 1 hr after bolus. MAIN RESULTS: Compared with anesthetized controls, core brain temperatures of the saline and slurry groups dropped by 3.4 +/- 0.4 degrees C and 5.3 +/- 0.7 degrees C (p = .009), respectively. With an infusion rate of 120 mL/min, cooling rates for the saline and slurry groups were -11.6 +/- 1.8 degrees C/hr and -18.2 +/- 2.9 degrees C/hr, respectively, during the first 20 mins. Four of four animals in the slurry group vs. zero of four animals in the saline group achieved target cortical temperatures of <34 degrees C. CONCLUSIONS: Cold intravenous fluids rapidly induce hypothermia in swine with intact circulation. A two-phase (liquid plus ice) saline slurry cools more rapidly than an equal volume of cold saline at 0 degrees C. Ice-slurry could be a significant improvement over other cooling methods when rate of cooling and limited infusion volumes are important to the clinician.

Oropharyngeal Necrobacillosis with Septic Thrombophlebitis and Pulmonary Embolic Abscesses: Lemierre's Syndrome in a New Zealand White Rabbit.

Lemierre's syndrome, oropharyngeal infections induced by anaerobic bacteria, leading to fatal septic thrombophlebitis of the internal jugular vein and pulmonary embolic abscesses in humans, was diagnosed in a 6-month-old, male, New Zealand White rabbit. After acute onset of anorexia, lethargy, and depression, the rabbit died suddenly despite emergency clinical care. Necropsy revealed swelling, necrosis, and abscess in the soft tissues around the left caudal mandibular ramus, oral mucosa, and molar teeth, with systemic embolic abscesses and necrosis, especially in the jugular vein, lungs, and brain. Histologic examination revealed necrosis and embolic abscesses with filamentous bacteria in the mandibular soft tissues, salivary gland, jugular veins, alveolar bone and marrow, periodontal tissues and dental pulp, oral and pharyngeal mucosa, lungs, brain, liver, myocardium, meninges, and small intestine. Bacterial culture of the mandibular abscess and heart blood yielded Fusobacterium necrophorum.

Bulbourethral Gland Cysts in Three Mice.

Diseases of bulbourethral glands have rarely been reported in mice. The present report describes bulbourethral gland cysts in three male mice: a.1yearold DBA/2J mouse (case 1), a 10monthold nude mouse (case 2), and a 4.5monthold chimeric mouse (case 3). Round to oval fluctuant nodules were observed on their dorsal perineum. The nodules in cases 1 and 2 were pale, pink to tan, soft, and glistening; in case 3, the mass was purple-red and soft. All nodules were located subcutaneously between the bulbospongiosus and ischiocavernous muscles, with a deep connection to the urethra. The nodules were 13 mm (case 1), 6 mm (case 2), and 8 mm (case 3) in diameter. The cut surface of the nodules was cystic; the lumina were filled with clear gelatinous or viscous (cases 1 and 2) or thin blood-tinged fluid (case 3). The nodules comprised irregular cysts and acini that were lined by a single layer of cuboidal, pyramidal to tall columnar epithelial cells with little stroma. Bulbourethral gland cysts should be included as differential diagnoses for perineal nodules or swellings in mice.

Renal Cell Carcinoma in Two Siberian Hamsters (Phodopus sungorus).

Renal cell carcinoma was diagnosed in 2 Siberian hamsters (Phodopus sungorus). One hamster had a unilateral solitary papillary-tubular carcinoma. The other hamster had a clear-cell, a papillary-tubular, and mixed types of carcinomas in the left kidney and a cystic-papillary-tubular type of carcinoma in the right kidney. In the papillary-tubular carcinoma. there were cuboidal to columnar cells arranged in tubular or papillary patterns supported by delicate fibrous stroma. Nuclei were located basally, often perpendicular to the subjacent basement membrane. Cytoplasm was pale to eosinophilic and variably abundant. Pleomorphic oval to polygonal cells found in the clear-cell carcinoma were arranged in broad trabeculae, lobules, or nests, with congested capillary stroma and multifocal necrosis. Cytoplasm varied from eosinophilic and granular to pale and clear or vacuolated. In the cystic-papillary-tubular carcinoma, cuboidal to columnar cells were arranged in cystic, papillary, or tubular patterns. Cysts varied in size and shape and contained secretory material and erythrocytes.