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Biomedical subjects

C H Tator

Publications and source records attributed to C H Tator.

At least 199 records · Page 11Linked to original sources
PubMed1977

Objective clinical assessment of motor function after experimental spinal cord injury in the rat.

A new method was developed for the clinical assessment of motor function in rats after experimental spinal cord injury. The method consists of placing the animal on an inclined plane which can be adjusted to provide a slope of varying grade, and then assessing the maximum angle of the plane at which the animal can maintain its position without falling. The method was used to quantitate motor function in normal rats and in rats subjected to myelectomy, and consistently showed major differences between the two groups. The method has many positive features: the plane is easy to construct and of low cost; and the test is rapid, non-invasive, repeatable, and consistent.

Animals↗
PubMed1977

Chemotherapy of an experimental glioma with nitrosoureas.

Chemotherapy experiments were performed with 2 nitro-sourea drugs in an experimental mouse brain tumor model. Cell suspensions of a transplantable mouse ependymoblastoma were injected i.c. by means of a stereotactic frame. The drugs used were 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea and 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea and were given by either i.p. or by direct intraneoplastic (i.n.) injection on the fifth day after tumor cell implantation. Injections i.n. of drugs were made with the stereotactic frame. Both drugs were highly effective in increasing the median day of death and in yielding large numbers of long-term survivors. Effectiveness was evident after i.p. or i.n. injection. However, with certain dosage schedules such as every 2 hr for 5 injections daily on 2 consecutive days, i.n. injection was more effective and less toxic than i.p. injection. The reason why repeated i.n. injections produced less toxicity than repeated i.p. injections is not definitely known but may be due to local metabolism of the drugs in the tumors and surrounding brain to a less toxic form. This is the first laboratory report of direct i.n. injection of the nitrosoureas, and the authors consider these results encouraging.

Animals↗
PubMed1977

Intraneoplastic injection of CCNU for experimental brain tumor chemotherapy.

Chemotherapy experiments were performed with 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) in an experimental mouse brain tumor model. Cell suspensions of a transplantable mouse ependymoblastoma were injected intracerebrally by means of a stereotactic frame. CCNU was given either intraperitoneally or by direct intraneoplastic injection beginning the fifth day after tumor cell implantation. Intraneoplastic injection beginning the fifth day after tumor cell implantation. Intraneoplastic injections of drugs were made with the stereotactic frame. A single intraneoplastic injection of CCNU was found to be highly effective in increasing the median day of death and in yielding large numbers of long-term survivors. In some experiments CCNU injected into the neoplasm produced increased numbers of long-term survivors and less systemic toxicity than when injected intraperitoneally.

Animals↗
PubMed1976

Review of the measurement of normal spinal cord blood flow.

The field of spinal cord blood flow (SCBF) is reviewed. The methodology currently being used to evaluate SCBF is critically analyzed. The review demonstrates that there is a paucity of reliable quantitative measurements of SCBF. The effects of arterial pCO2, pO2 and blood pressure variations as well as the effects of several pharmacological agents on SCBF are also discussed.

Animals↗
PubMed1976

Carbohydrates as potential diagnostic tracers for brain tumors.

Currently available diagnostic tracers for brain tumors are not specific. Tumor-specific tracers would improve the detection of brain tumors by gamma encephalography. Glucose is an important substrate for tumor metabolism and is known to be taken up in large amounts. The authors have studied five labeled carbohydrates in an attempt to find a tumor-specific tracer: three were tritiated (L-galactose-1-3H, L-fucose-3H, and 4,6-dideoxy-xylo-hexose-3H) and two were radioiodinated (methyl-6-125I-6-deoxy-D-glucoside and 6-125I-6-deoxy-D-glucose). The uptake of these tracers by a transplantable mouse ependymoblastoma after intravenous injection was determined by liquid and well scintillation counting. The highest tumor-to-brain ratio was 7.1 to 1 for the tritiated tracers and 6.2 to 1 for the radioiodinated tracers. Although these ratios are not high enough for gamma encephalography, one of the iodinated tracers may be useful for enhancement of contrast in computerized axial tomography.

Animals↗
PubMed1976

Review of the effect of spinal cord trama on the vessels and blood flow in the spinal cord.

The effect of spinal cord trauma on the vasculature and blood flow of the spinal cord is reviewed. Both quantitative and nonquantitative studies are critically discussed and reasons sought for some of the major controversies that have arisen. Differences in methodology, species variation, and variation in the degree and type of cord injury may all be important factors in producing the conflicting results reported in the literature. In general, it can be said that trauma has a profound effect on the vasculature and blood flow in the cord and that severe compression injury of the cord causes marked ischemia in the gray and white matter.

Animals↗
PubMed1976

Regional spinal cord blood flow in primates.

Spinal cord blood flow (SCBF) was measured in the primate thoracic spinal cord using the 14C-antipyrine autoradiographic technique that allowed clear differentiation between white and gray matter blood flow. Individual SCBF values were obtained for 0.1-sq mm areas of the thoracic cord cross section. White matter blood flow was homogeneous throughout with a mean value of 10.3 +/- 0.2 ml/100 gm/min. Gray-matter flow was more variable with lower values in the dorsal horns and higher values in the central gray and anterior horns. Mean gray-matter flow was 57.6 +/- 2.3 ml/100 gm/min. Arterial pO2 was 123 +/- 2 torr, pCO2 was 40.2 +/- 0.5 torr and pH was 7.327 +/- 0,010. Mean arterial blood pressure was 113 +/- 3 mm Hg and core temperature was 36.4 degrees +/- 0.1 degrees C.

Animals↗
PubMed1976

Effect of acute spinal cord compression injury on regional spinal cord blood flow in primates.

Spinal cord blood flow (SCBF) was measured in 24 rhesus monkeys after injury to the cord produced by the inflatable circumferential extradural cuff technique. Measurement of regional blood flow in the white and gray matter of the cord in areas of 0.1 sq mm was achieved with the 14C-antipyrine autoradiographic technique and a scanning microscope photometer. After moderate cord injury (400 mm Hg pressure in the cuff maintained for 5 minutes), which produced paraplegia in 50% of animals and moderate to severe paresis in the other 50%, mean white matter SCBF was significantly decreased for up to 1 hour. White matter blood flow then rose to normal levels by 6 hours posttrauma and was significantly increased by 24 hours posttrauma. Gray matter SCBF was significantly decreased for the entire 24-hour period posttrauma. After severe cord injury (150 mm Hg pressure in the cuff maintained for 3 hours), which produced total paraplegia in almost all animals; SCBF in white and hours), which prodced total paraplegia in almost all animals, SCBF in white and gray matter was reduced to extremely low levels for 24 hours posttrauma. In addition, focal decreases in SCBF were seen in white and gray matter for considerable distances proximal and distal to the injury site. It is concluded that acute compression injury of the spinal cord is associated with long-lasting ischemia in the cord that increases in severity with the degree of injury.

Acute Disease↗
PubMed1976

Retention of tritiated methotrexate in a transplantable mouse glioma.

The uptake and distribution of tritiated methotrexate ([H]MTX) were studied by autoradiography and liquid scintillation countinf for up to 7 days after i.v. injection in mice bearing s.c. or intracerebral (i.c.) implants of a transplantable mouse ependymoblastoma. Autoradiography showed that s.c. tumors took up more [3H]MTX than i.c. tumors. In both s.c. and i.c. tumors, [3H]MTX was mainly intracellular, with very little in intersitial fluid sites. Retention of [3H]MTX gradually diminished with time, with some still being present 7 days after injection. The distribution of [3H]MTX in the i.c. tumors was not uniform, and portions of these tumors were relatively inaccessible to the drug. The uniformity of distribution did not improve with time. Scintillation counting showed that s.c. tumors accumulated much less [3H-A1MTX and retained a lower proportion of [3H]MTX than many normal tissues. These studies indicate that [3H]MTX has 3 major shortcomings as a chemotherapeutic agent for brain tumors. First, the amount of drug taken up by the transplantable mouse ependymoblastoma was small in comparison with normal tissues and in comparison with other agents taken up by this tumor. Second, the distribution of the drug in the i.c. tumors was nonuniform, with tumor cells in certain areas remaining relatively inaccessible to the drug. Last, the retention of the drug in the tumor was far less than in normal tissues.

Animals↗
PubMed1975

Glucose analogs as potential diagnostic tracers for brain tumors.

No tumor-specific tracer has yet been found for the detection of brain tumors by external scintiscanning. Glucose is a substrate in high demand by almost all tumors, and therefore an investigation was undertaken into the potential value of glucose and its analogs as tracers for brain tumors. The compounds studied were D-)1-3H)glucose, D-(1-14C)glucose, (3H)3-O-methyl-D-glucose and L-(1-14C)glucose. The tracers were injected i.v. into C57BL/6J mice carrying a transplantable s.c. ependymoblastoma. At specific time intervlas after injection, mice were sacrificed and the radioactivity of 6 tissues including tumor and brain were assayed by means of an automated combustion technique and liquid scintillation counting. Tumor uptake, expressed as percentage mean body concentration, was 60% for 2 of the tracers, and 92 and 143%, respectively, for 2 others. Brain uptake was over 130% mean body concentration, with 3 of the 4 tracers studies. With L-glucose, brain uptake was only 15.4% mean body concentration, and a maximum tumor-to-brain ratio of 9.5 was achieved. The very high tumor uptake achieved with two of these carbohydrated demonstrates that a carbohydrate analog may be found that shows high tumor specificity and uptake, and that may be useful for external scintiscanning.

Animals↗