Harold D. Snow

Transjugular portal venography and radiologic portacaval shunt: an experimental study.

Conventional methods of opacifying the portal system are splenic portography (1) and intra-arterial contrast injections into the visceral arteries with delayed films (6). More exotic means reported include translumbar portal vein puncture (4), umbilical vein catheterization (2), hemorrhoidal vein cannulization under spinal anesthesia (7), or laparotomy with cannulization of a mesenteric vein branch (5). All methods produce good to fair opacification of the portal venous system but allow no selectivity of contrast injections or opportunities for manipulative procedures in the venous system. For two years we have performed cholangiography (3) by passing a modified Ross needle and catheter system down the internal jugular vein and superior vena cava, across the right atrium into the inferior vena cava, and then into the hepatic veins in order to puncture the biliary duct system from inside the liver. With this same approach, one of the major branches of the portal vein can be punctured and the catheter inser...

Thermomagnetic surgery for cancer.

Thermomagnetic Surgery is a unique technique that takes advantage of the phenomenon of hysteresis heating of a ferromagnetic material to produce intense but controlled temperatures within solid organs or tumors to cause coagulation necrosis. By controlling the power of the electromagnetic coil system, the degree of heating of the tumor can be controlled through temperature monitoring that allows limitation of the area of destruction to the disease process and avoids damage to surrounding structures. If the ferromagnetic material is delivered by the arterial route to the tumor or organ, there is an additional beneficial effect of ischemic necrosis of the tissue and in time more concentration of the ferromagnetic particles. This new technique is applicable to selected cases of human cancer because no ill effect has been shown to exposure of the electromagnetic field or the ferromagnetic material in experimental animals.

Thermomagnetic surgery for cancer

Thermomagnetic Surgery is a unique technique that takes advantage of the phenomenon of hysteresis heating of a ferromagnetic material to produce intense but controlled temperatures within solid organs or tumors to cause coagulation necrosis. By controlling the power of the electromagnetic coil system, the degree of heating of the tumor can be controlled through temperature monitoring that allows limitation of the area of destruction to the disease process and avoids damage to surrounding structures. If the ferromagnetic material is delivered by the arterial route to the tumor or organ, there is an additional beneficial effect of ischemic necrosis of the tissue and in time more concentration of the ferromagnetic particles. This new technique is applicable to selected cases of human cancer because no ill effect has been shown to exposure of the electromagnetic field or the ferromagnetic material in experimental animals.

Successful radiation protection of the normal intestinal tract in the dog.

Successful experimental radiation protection of the small bowel and the proximal colon has been achieved in controlled animal studies, utilizing a selective superior mesenteric artery infusion of vasopressin during abdominal irradiation. The success of this technique contrasts with the nonreliability of a combination of propranolol and epinephrine infused by the same route. The differences in efficacy of these two categories of vasoconstrictors may be related to differences in the locus of activity of vasopressin and propranolol-epinephrine in the mesenteric arterial tree.

Regional intralymphatic infusion (ILI) of irradiated tumor cells with evidence of distant effects.

A case of canine lymphoma with radiographically‐documented involvement of the para‐aortic nodes is reported. Intralymphatic infusions (ILI) of cultured irradiated autochthonous tumor cells to remote lymph node bearing areas were associated with a dramatic initial shrinkage of the para‐aortic lymphadenop‐athies. Three ILI timing schedules were used consecutively during a course of 10 treatments, allowing a comparison of responses in the same animal. The reported case suggests that a normal lymph node can be effectively “stimulated” by the same agent approximately every 3 weeks. A possible schedule for intralymphatic infusion is proposed for further investigation.

Intralymphatic infusion of autochthonous tumor cells in canine lymphoma

Abstract The feasibility of repeated intralymphatic injections of cellular materials was investigated in dogs having spontaneous lymphomas. Forty-two administrations of enzymatically-modified irradiated autochthonous tumor cell preparations were performed with minimal difficulty and negligible deleterious side effects, indicating that the intralymphatic route of administration and these methods of cell vaccine preparation may be safely used for further pre-clinical investigations. Although the number of animals treated thus far is insufficient to realistically evaluate the immunotherapeutic potential of this method, all treated tumor-bearing dogs demonstrated marked reduction in tumor volume and significant clinical improvement.

Radiation protection of the normal kidney by selective arterial infusions

Successful unilateral renal radioprotection has been attained in 10 of 18 experimental animals receiving protracted and fractionated radiation to large abdominal fields and unilateral renal artery epinephrine infusions, including 6 of the last 7 animals so treated. In a pilot series of patients with Stage III ovarian malignancies who were treated in a similar manner with unilateral renal artery epinephrine infusions, successful unilateral renal radioprotection has also been achieved in 3 out of 5 evaluable patients (the other 2 patients received potentially nephritic radiation doses to both kidneys, but have not in fact developed radiation nephritis on either side). In a series of 10 experimental animals, production of temporary unilateral renal hypoxia during abdominal irradiation by the use of a balloon occlusion catheter has not proved reliable in effecting unilateral renal radioprotection. However, in a subgroup of 5 animals, the data suggest that simultaneous infusion of a vasoconstrictor combination into the superior mesenteric artery during irradiation may prevent morbidity and mortality from acute radiation enteritis, under the experimental conditions employed.

External field electromagnetic measurement of blood flow

SummaryAn electromagnetic intravascular rate of volume flow meter of minimal dimensions is described. It is activated by an extracorporeal magnetic field. The location at the apex of the aortic arch minimizes ECG artifacts and circumvents the problem of securing a zero-flow baseline which is given by the lowest mid-diastolic flow level. The magnetic field at the electrodes is maximized by placing the subject axially into the magnetic coil. The flow transducer also offers a means of measuring the artery diameter and its pulsations. The electromagnetic flow measurements of cardiac output agree within about 20% with dyedilution technique determinations.

An Indwelling Silastic Cannula for Repeated Vascular Access in Experimental Animals

Repeated catheterization of vessels in the experimental animal by the Seldinger technic is limited by vascular thrombosis and fibrosis in and around the punctured vessels (1, 2). In experimental situations, the repeated introduction of an intravascular catheter over periods of days, weeks, or months may be required in order to obtain serial angiograms from a single animal, repeated blood samples from a major vessel or a branch vessel, serial pressure measurements within the heart or in arteries or veins over an extended period of time, or for many other applications. The maintenance of a continuously indwelling vascular catheter in the experimental animal over days or weeks poses many technical problems including thrombosis of the catheter or destruction of the catheter by the animal itself. Therefore, repeated, i.e., intermittent, introduction of a vascular catheter for the purposes described above by a simple, atraumatic method would be highly desirable. Mills and Simmons reported a method for carotid a...

Minimum calcification demonstrable in pulmonary nodules. A roentgen pathology model.

Abstract Linked silicone rubber nodules of uniform size containing a monoblastic crystal of calcium phosphate [Ca(H2PO4)2·H2O] were implanted in a phantom chest and in the peripheral lung field of a living dog. Lateral and anteroposterior chest films and laminagrams revealed that the smallest calcium deposit demonstrable was 0.1 mg (0.4 µmoles of salt).