Evaluations of vascular disrupting agents CA4P and OXi4503 in renal cell carcinoma (Caki-1) using a silicon based microvascular casting technique.

The present study evaluated the treatment efficacy of the vascular disrupting agents CA4P and OXi4503 in an orthotopically transplanted human renal cell carcinoma xenograft model (Caki-1). Experiments used vascular casting, vessel density assessments as well as tumour necrosis measurements to evaluate the efficacy of these agents. After treatment with either agent, assessment of the vascular casts showed an almost total eradication of tumour blood vessels. Histological evidence further supported this observation, showing extensive central tumour necrosis with only a small viable rim of tumour cells remaining at the periphery. These results suggest that vascular disrupting agents CA4P and OXi4503 may have utility in the treatment of renal cell carcinoma, an encouraging result given that current conventional therapies have been currently largely unsuccessful in managing this disease.

Rate-dependent block in the sinus venosa of the swine heart during transverse right atrial activation: correlation between electrophysiologic and anatomic findings.

UNLABELLED: Rate-dependent block in the sinus venosa. INTRODUCTION: Whether the crista terminalis or the sinus venosa result in rate-dependent block during transverse activation of the right atrial activation remains unknown. In the present study, right atrial activation at different cycle lengths was studied in the swine heart using high-resolution noncontact mapping (Endocardial Solutions). The location of the block was tagged and correlated with postmortem anatomical findings. METHODS AND RESULTS: Eight pigs were studied using noncontact mapping to obtain right atrial geometry and detailed sequence of activation using noncontact endocardial mapping. During sinus rhythm, activation proceeded uninterrupted craniocaudally along the sinus venosa and crista terminalis with similar conduction velocities (1.08+/-0.17 and 1.17+/-0.14 m/sec, respectively). Proximal coronary sinus stimulation was used to create transverse activation of the posterior right atrial wall. A rate-dependent decrease in conduction velocity occurred in the sinus venosa region (0.93+/-0.21, 0.82+/-0.14, and 0.52+/-0.09 m/sec at 500, 400, and 300 ms, respectively; P<0.05). The line of block verified by isopotential mapping and double potentials was obtained at cycle lengths of 240+/-30 ms. This line of the block was tagged with radiofrequency current lesions. Postmortem, all lesions were located in the sinus venosa region, 9.8+/-4.1 mm from the posteromedial edge of the crista terminalis. This region showed abrupt changes in muscle fiber thickness and orientation as well as in collagen content. CONCLUSIONS: The sinus venosa and not the crista terminalis results in a rate-dependent line of block during transverse right atrial activation. The morphologic characteristics of the sinus venosa appear to facilitate block in this region.

Lymph sampling and lymphangiography via EUS-guided transesophageal thoracic duct puncture in a swine model.

BACKGROUND: The thoracic duct plays an important role in fluid balance, lipid absorption, and transport of immunologically active cells. The thoracic duct is difficult to access but is readily identified by EUS. The present study assessed the feasibility of EUS identification and EUS-guided puncture of the thoracic duct in a swine model. METHODS: Transesophageal EUS-guided thoracic duct puncture was attempted in 3 animals under fluoroscopy. In two animals, the thoracic duct was identified by cutdown in the neck; in the third animal, EUS-guided puncture was performed under fluoroscopy alone. In one animal, the thoracic duct was opacified by injecting contrast medium. In the second animal, thoracic duct was injected with patent blue and contrast medium. OBSERVATIONS: Thoracic duct was identified and punctured successfully in all 3 animals. In the first animal, contrast medium containing lymph was aspirated. In the second animal, lymph containing patent blue was aspirated, and, in the third animal, successful puncture was confirmed by obtaining a lymphangiogram. CONCLUSIONS: This pilot study in an animal model demonstrates that transesophageal EUS-guided puncture of the thoracic duct is feasible and that the technique can be used for lymph sampling and/or lymphangiography.

Anatomy of the crocodilian spinal vein.

The crocodilian spinal vein is remarkably robust yet historically overlooked. Using corrosion casting, we describe the anatomy of this vessel and its connections with the caval and hepatic venous systems in representatives from four crocodilian genera. The spinal vein arises from an enlarged occipital sinus over the medulla and extends the entire length of the vertebral column. Unlike in squamate reptiles, the spinal vein is single (nonplexiform), voluminous, and situated dorsal to the spinal cord, and plexi lateral to the cord span between emerging intercostal veins. The connections with the other venous systems are otherwise similar to those in other tetrapods. The overall anatomy of this vessel and its abundant connections with the other venous systems indicate it likely plays a primary role in returning blood to the heart from all parts of the body. Preliminary studies of function suggest that this vessel could also play an adaptive role during basking and diving.