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Biomedical subjects

H D Snow

Publications and source records attributed to H D Snow.

At least 19 recordsLinked to original sources
PubMed1987

Leksell stereotactic radiosurgery in the treatment of eye melanoma.

Current experiments indicate that a focussed single radiation treatment with a dose of 6000 to 9000 rads delivered to the 90% zone through a collimator of the Leksell stereotactic radiosurgical unit or 'gamma knife' to the rabbit eye melanoma model is capable of destroying the cancer totally and thus effecting a cure. The beneficial effect in these rabbit eye melanoma experiments appears to be similar to the results obtained by physicians using the Harvard and Berkeley cyclotrons in treating malignant neoplasms in the human eye. Therefore, it is proposed that a properly designed stereotactic radiosurgical unit can be used in patients with eye tumours similar to those selected for the cyclotron systems.

Animals↗
PubMed1982

Thermo-magnetic surgery for experimental renal cancer.

Thermo-magnetic surgery is an innovative modality in the treatment of malignancies. This unique combination can produce selectively controlled destruction of deep tumors. Heating of the magnetic metallic compounds of ferrosilicone by hysteresis produces temperatures which are incompatible with cancer cell survival. The intense focal heating causes a coagulation necrosis. Damage to surrounding normal tissue can be avoided by careful temperature monitoring and power control of the magnetic field. Cell destruction in the target tissue has been demonstrated by light and electron microscopy. Reproducible and predictable VX2 renal carcinomas in rabbits have been produced and used as the tumor model in the initial experiments of this research project. A clinical trial with selected cancer patients, performed with this technique of thermo-magnetic surgery, is now a reasonable and feasible procedure.

Animals↗
PubMed1982

Thermomagnetic surgery for renal cancer.

Thermomagnetic surgery is a technique that uses hysteresis heating of ferromagnetic materials to produce focally controlled temperatures within solid organs or tumors to cause coagulation necrosis. The degree of heating of a neoplasm is controlled by manipulating the power of the electromagnetic coil system through temperature monitoring. This effectively limits the region of destruction to the disease process and thereby avoids damage to surrounding structures. If the ferromagnetic material is delivered by an arterial route to the tumor or organ additional beneficial effect of ischemic necrosis of tissue may be achieved. This new technique is applicable to selected cases of human cancer. Exposure in the electromagnetic fields or use of the ferromagnetic material in experimental animals has produced no ill effects.

Animals↗
PubMed1980

Evaluation of neoalleviase (NA-1700) in heroin detoxification: preliminary report on toxicity and efficacy including prophylactic measure in mice and clinical study.

Neoalleviase (NA-1700) is a specially formulated unique combination of 14 well-identified species of higher plants whose extracts were obtained through an enzymatic process with macerozymes prior to clinical study. Toxicity and efficacy tests were satisfactorily performed by bioassay with 120 mice under double-blind conditions for 82 days. Straub tests facilitated efficacy proof in mice. Neoalleviase (530 mg capsules q.i.d.) was administered to 268 active heroin addicts under double-blind conditions. The established dosage schedule was utilized over a 35 day drug administration period (maximum) with a follow-up observation at 10 months. Himmelsback's techniques were used to determine withdrawal scores. The results of this study indicated that Neoalleviase (NA-1700) effectively suppressed withdrawal signs and symptoms without undesirable major side effects at the given therapeutic dose level. It appears to be potentially the most promising heroin detoxification agent.

Adult↗
PubMed1978

Differential effects of Pitressin on blood flow and oxygen extraction in canine vascular beds.

Physiologic studies in dogs have been performed with an intravascular flow/diameter sensor which can be introduced directly into the aorta or its branch vessels through a percutaneous radiologic catheter. These studies have focused upon attempts to devise a clinically practical means to protect the small intestine from radiation damage during therapy of abdominal and pelvic malignant tumors. The effects on superior mesenteric, renal, and lower extremity blood flows of controlled infusions of Pitressin given directly into the superior mesenteric artery or into a peripheral vein have been measured. In addition, using these regional flow measurements and arteriovenous differences in oxygen content, regional tissue oxygen extraction rates during Pitressin infusions have also been estimated. The data show that intravenous Pitressin at an infusion rate of 0.0124 U/kg/min may be almost as effective as Pitressin given directly into the superior mesenteric artery in lowering superior mesenteric blood flow (40%-70% reduction for intravenous, 50%-70% for direct arterial infusions) and intestinal oxygen extraction (20%-40% reduction for intravenous, 40%-50% for direct arterial infusions). The effects of Pitressin at similar dose rates on the kidney and the lower extremity are less reproducible, and it is possible that relatively selective radiation protection of the intestine using systemic (intravenous) infusions of Pitressin during abdominopelvic radiotherapy might be achievable.

Animals↗
PubMed1977

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 lymphadenopathies. 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.

Animals↗
PubMed1976

Extracorporeal magnet perivascular electromagnetic flow meters.

The "interrupted resonance" circuit proved effective in combination with an extracorporeal magnet in permitting electromagnetic blood flow measurements to be made in branch arteries of dogs by application of perivascular cuffs equipped with pick-up electrodes contacting the vessel wall. A four-turn coil, acting as a transformer secondary measures the amplitude of the magnetic field component which is effective in inducing the flow signal and thus permits calibrations for arbitrary orientations of the perivascular cuff relative to the magnetic field of the extracorporeal magnet. Recordings of mean and phasic blood flow in dogs' arteries provide illustrations of effectiveness in pharmacological studies and exhibit the reliability of the non-occlusive zero-flow base line obtained by de-energizing the magnet.

Animals↗
PubMed1975

Old dog encephalitis and demyelinating diseases in man.

Pathologic findings in mature dogs with old dog encephalitis were compared with the findings in multiple sclerosis, subacute sclerosing panencephalitis and neuromyelitis optica in man. Fluorescent antibody studies in animal and human tissues were compared. Optic neuritis in dogs with chronic distemper shows changes similar to those in the optic tract of human patients with severe demyelinating disease. The pathologic changes in multiple sclerosis, such as perivascular infiltration with lymphocytes, plasma cells and demyelination are similar to those seen in old dog encephalitis. Demyelination in old dog encephalitis is usually diffuse. The findings strongly support a possible relationship of old dog encephalitis to multiple sclerosis, subacute sclerosing panencephalitis, and neuromyelitis optica.

Animals↗