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Glucuronolactone decarboxylase in muscular dystrophy
Report of meeting (ii)
159
It emits gamma rays with much less energy, facilitating shielding and safer handling; (iii) It has a greater gamma ray "merit" ratio Useful gamma ray "signals" Localized beta particle radiobiologic effect (iv) "Directionality" is more readily achievable. (8) Radiation exposures are reduced, in in accordance with recommendations made recently by Study Committees of the National Academy of Sciences.
mately ten such tests have been performed on human muscle biopsy specimens obtained at surgery from patients with myopathies and neuropathies, and they showed a small although significant difference. The animal work on which many hundreds of these tests were performed continues with the purpose of determining coenzyme factors and conditions which would increase the sensitivity and accentuate the differences between comparative specimens.
G l u c u r o n o l a c t o n e D e c a r b o x y l a s e in M u s c u lar D y s t r o p h y : JOSEPH L. RABINOWITZ
RAYMOND G. ROSE, M.D., F.R.C.P. (C), The University of Texas Postgraduate School of Medicine, University of Texas M. D. Anderson Hospital, Houston, Texas. High doses of irradiation are required to produce definite morphological changes in the central nervous system. The present experiment was conducted to see if functional derangements occur after comparatively small amounts of ionizating radiations. Tracer studies with intravenously injected radioactive sodium were performed on rabbits to determine the rate and degree of sodium penetration into the cerebrospinal fluid and brain. Other groups of rabbits were given large doses of Na ~4 or 100 to 1500 r of total body X-radiation (followed by tracer doses of Na e4 at varying intervals) to study the possible effects of such irradiation. The data obtained showed an accelerated penetration of sodium into the CNS under these conditions, as well as an apparent increase in radio-sodium content in the CNS when compared to the control group. Histological changes were minimal at the highest dosage levels employed. The significance and possible applications of these findings are discussed.
Methodist Hospital, Texas Center, Houston, Texas.
Medical
It was possible by the use of radioactive glucuronolactone to devise a test capable of indicating the amount of this enzyme present in a given specimen. It was hoped when this enzyme was discovered and the assay test developed that it would prove a clinical aid in the diagnosis of myopathies. At present, extensive laboratory work is being correlated by the use of the recently found strain of dystrophic mice. Although this enzyme is apparently present to a larger extent in certain organs (kidney, spleen, etc.) in the dystrophic animal as compared to the normal litter mate, in the muscle itself the difference is small and therefore hard to measure. A larger difference in the content of this enzyme in the muscle of the dystrophic patient would be necessary for the development of a practical diagnostic test, since the difference between the normal and the dystrophic muscle is small. The alternatives are a more sensitive test or a biopsy of an organ known to exhibit a greater enzymatic difference. The glucuronolactone decarboxylase test consists of the measurement of radioactive CO S formed per mg of a weighed sample of finely minced tissue after incubation with 1 mg of 1 mc m M of C14 multilabel glucuronalactone. This test is at present a laboratory investigative procedure. Approxi-
P h y s i o - P a t h o l o g i c Effects of I o n i z i n g Radia t i o n s on the B l o o d - B r a i n Barrier as M e a s u r e d b y the P e n e t r a t i o n of R a d i o A c t i v e S o d i u m into the Central N e r v o u s
System :
Four Inches by T h r e e Inches Plastic Scintillator for R o u t i n e Co 60 V i t a m i n B12 U p t a k e s : W. S. STAFF and P. C.
JOHNSON, Veterans Administration Hospital, Oklahoma City, Oklahoma.
159
It emits gamma rays with much less energy, facilitating shielding and safer handling; (iii) It has a greater gamma ray "merit" ratio Useful gamma ray "signals" Localized beta particle radiobiologic effect (iv) "Directionality" is more readily achievable. (8) Radiation exposures are reduced, in in accordance with recommendations made recently by Study Committees of the National Academy of Sciences.
mately ten such tests have been performed on human muscle biopsy specimens obtained at surgery from patients with myopathies and neuropathies, and they showed a small although significant difference. The animal work on which many hundreds of these tests were performed continues with the purpose of determining coenzyme factors and conditions which would increase the sensitivity and accentuate the differences between comparative specimens.
G l u c u r o n o l a c t o n e D e c a r b o x y l a s e in M u s c u lar D y s t r o p h y : JOSEPH L. RABINOWITZ
RAYMOND G. ROSE, M.D., F.R.C.P. (C), The University of Texas Postgraduate School of Medicine, University of Texas M. D. Anderson Hospital, Houston, Texas. High doses of irradiation are required to produce definite morphological changes in the central nervous system. The present experiment was conducted to see if functional derangements occur after comparatively small amounts of ionizating radiations. Tracer studies with intravenously injected radioactive sodium were performed on rabbits to determine the rate and degree of sodium penetration into the cerebrospinal fluid and brain. Other groups of rabbits were given large doses of Na ~4 or 100 to 1500 r of total body X-radiation (followed by tracer doses of Na e4 at varying intervals) to study the possible effects of such irradiation. The data obtained showed an accelerated penetration of sodium into the CNS under these conditions, as well as an apparent increase in radio-sodium content in the CNS when compared to the control group. Histological changes were minimal at the highest dosage levels employed. The significance and possible applications of these findings are discussed.
Methodist Hospital, Texas Center, Houston, Texas.
Medical
It was possible by the use of radioactive glucuronolactone to devise a test capable of indicating the amount of this enzyme present in a given specimen. It was hoped when this enzyme was discovered and the assay test developed that it would prove a clinical aid in the diagnosis of myopathies. At present, extensive laboratory work is being correlated by the use of the recently found strain of dystrophic mice. Although this enzyme is apparently present to a larger extent in certain organs (kidney, spleen, etc.) in the dystrophic animal as compared to the normal litter mate, in the muscle itself the difference is small and therefore hard to measure. A larger difference in the content of this enzyme in the muscle of the dystrophic patient would be necessary for the development of a practical diagnostic test, since the difference between the normal and the dystrophic muscle is small. The alternatives are a more sensitive test or a biopsy of an organ known to exhibit a greater enzymatic difference. The glucuronolactone decarboxylase test consists of the measurement of radioactive CO S formed per mg of a weighed sample of finely minced tissue after incubation with 1 mg of 1 mc m M of C14 multilabel glucuronalactone. This test is at present a laboratory investigative procedure. Approxi-
P h y s i o - P a t h o l o g i c Effects of I o n i z i n g Radia t i o n s on the B l o o d - B r a i n Barrier as M e a s u r e d b y the P e n e t r a t i o n of R a d i o A c t i v e S o d i u m into the Central N e r v o u s
System :
Four Inches by T h r e e Inches Plastic Scintillator for R o u t i n e Co 60 V i t a m i n B12 U p t a k e s : W. S. STAFF and P. C.
JOHNSON, Veterans Administration Hospital, Oklahoma City, Oklahoma.