Enzymatic Synthesis and Organ Distribution Studies with<sup>13</sup>N-Labeled L-Glutamine and L-Glutamic Acid

Gelbard, Alan S.; Clarke, Laurence P.; McDonald, J. M.; Monahan, W.G.; Tilbury, R.S.; Kuo, Ti-Jung; Laughlin, John S.

doi:10.1148/116.1.127

Cited by 69 publications

(14 citation statements)

References 7 publications

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“…The irradiated water contains predominantly 1 3~O ; with some 13NO;, with yields of up to 100 mCi ml-l. I3N0; and 13NO; were converted to 1 3 N~: with de Varda's alloy (Gelbard et al 1975, Vaalberg et al 1975. Irradiated water was transferred from the target by remote application of pressure into a vessel containing 0.5 g of de Varda's alloy and 0.5 g of NaOH.…”

Section: Methodsmentioning

confidence: 99%

Use of 13N as tracer for bacterial and algal uptake of ammonium from sea-water

Fuhrman¹,

Horrigan²,

Capone³

1988

Mar. Ecol. Prog. Ser.

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The relative importance of phytoplankton and heterotrophlc bacteria in the ut~lization of ammonium in a temperate coastal pelaglc environment (Long Island Sound. New York, USA) was examined uslng the short-lived radioisotope, I3N Uptake of ' 3~~: Into different slze fractions under simulated in situ temperature and light condihons was compared to size fractionations of bacterial abundance, chlorophyll, and uptake of tritlated thymidme and 14C-b~carbonate In January and Apnl, little ' 3~ entered the bactenal slze fract~on, but when bacteria were more metabolically a c t~v e in May and July, about '/3 of the total I3N uptake appeared in the size fraction conta~ning most of the bactena but httle of the chlorophyll (0 2 to 0 6 ,pm) Exposure to up to 8 mC1 I-' of I3N radioactivity d~d not ~n h~b~t bacterial or phytoplankton activity, and hlled controls showed virtually no uptake Ammonium uptake rates measured by I3N were comparable to those measured by the stable isotope 15N in 2 of 3 experiments The size fract~onation results were consistent wlth estimates of bactenal and phytoplankton demand tor nitrogen for growth Turnover rates for the dissolved a m m o n~u m pool ranged from 0 6 % h-' in April to 116 O/ O h-' in July In separate experiments .r\~th mlxed seawater cultures of bactena, the half-saturation constant (K,) for ammonium uptake was 1 0 1 uM, and ammonium uptake was reduced more by additions (100 to 1000 nM) of glutamine than by glutamate or othel ainlno a c~d s suggesting that glutamlne is directly ~nvolved in a m m o n~u m uptake In these bacteria

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Section: Methodsmentioning

confidence: 99%

Use of 13N as tracer for bacterial and algal uptake of ammonium from sea-water

Fuhrman¹,

Horrigan²,

Capone³

1988

Mar. Ecol. Prog. Ser.

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“…Glutamine, formed by skeletal muscle, brain, and other organs during periods of hyperammonemia, is a likely candidate in this regard. Gelbard et al (11) have shown that intravenously injected '3N-glutamine is taken up by the liver in normal dogs. In experiments in which 15N-glutamine was administered intravenously in rats, 15N-urea was recovered from the liver within 10 min (7).…”

Section: * Includes Isotope In Tumormentioning

confidence: 98%

“…'3N-Ammonia was produced by the 160(p,a)13N nuclear reaction, using a water target and a proton beam from a cyclotron, as described by Gelbard et al (11). The 13N-ammonia, produced by this method, is essentially radiochemically pture and carrier-free.…”

Section: Introductionmentioning

confidence: 99%

The dynamics of ammonia metabolism in man. Effects of liver disease and hyperammonemia.

Lockwood¹,

McDonald²,

Reiman³

et al. 1979

J. Clin. Invest.

376

201

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A B S T R A C T The cyclotron-produced radionuclide, 13N, was used to label ammonia and to study its metabolism in a group of 5 normal subjects and 17 patients with liver disease, including 5 with portacaval shunts and 11 with encephalopathy. Arterial ammonia levels were 52-264 ,AM. The rate of ammonia clearance from the vascular compartment (metabolism) was a linear function of its arterial concentration: Amol/min = 4.71 [NH3Ia + 3.76, r = +0.85, P < 0.005. Quantitative body scans showed that 7.4+±0.3% of the isotope was metabolized by the brain. The brain ammonia utilization rate, calculated from brain and blood activities, was a function of the arterial ammonia concentration: ,umol/ min per whole brain = 0.375 [NH3]a -3.6, r = +0.93, P < 0.005. Assuming that cerebral blood flow and brain weights were normal, 47 + 3% of the ammonia was extracted from arterial blood during a single pass through the normal brains. Ammonia uptake was greatest in gray matter. The ammonia utilization reaction(s) appears to take place in a compartment, perhaps in astrocytes, that includes <20% of all brain ammonia. In the 11 nonencephalopathic subjects the [NH3Ia was 100±8 ,uM and the brain ammonia utilization rate was 32±3 ,umol/min per whole brain; in the 11 encephalopathic subjects these were respectively elevated to 149±18 AM (P < 0.01), and 53 ± 7 ,umol/min per whole brain (P <0.01). In normal subjects, -50% of the arterial ammonia was metabolized by skeletal muscle. In patients with portal-systemic shunting, muscle may become the most important organ for ammonia detoxification.

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“…Nitrogen-13-labelled glutamate (N-13-glut), for example, prepared by an enzymatic synthesis (Gelbard 1975), was used to image patients with primary osteogenic sarcoma and Ewing's sarcoma (Gelbard et al 1979;Reiman et al 1981;Reiman et al 1982). The scans demonstrated a more marked change in radioactivity accumulation compared with 99mTc-MDP following chemotherapy.…”

Section: Soft-tissue and Musculoskeletal Sarcomamentioning

confidence: 99%

Positron emission tomography with 2-[18F]-fluoro-2-deoxy-D-glucose in oncology

Stokkel

Draisma

Pauwels

2001

Journal of Cancer Research and Clinical Oncology

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Positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) is considered to be a very useful adjunct to anatomic imaging techniques and is now primarily used for oncological indications. These indications include diagnosis, staging, and therapy monitoring. In this review, we discuss the articles in which FDG-PET is clinically used for monitoring therapy in lung and colorectal tumours, head and neck cancer, sarcoma, and hepatocellular carcinoma. It is found that the amount of FDG uptake strongly correlates with response to therapy: a decrease in FDG uptake after therapy indicates a positive response to therapy. However, this conclusion is based on small numbers of patients, whereas the exact response mechanism is still unknown. Moreover, in these case series, the interval between tumour therapy and FDG-PET, as well as the method of quantification, SUV or tumour-to-non-tumour ratios, differ per study. Finally, dynamic imaging is a recommended technique by some authors, but it is not a standard technique in clinical practice to evaluate tumour therapy. Therefore, further study is required which has to deal with these major issues before it is possible to draw definite conclusions.

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Enzymatic Synthesis and Organ Distribution Studies with¹³N-Labeled L-Glutamine and L-Glutamic Acid

Cited by 69 publications

References 7 publications

Use of 13N as tracer for bacterial and algal uptake of ammonium from sea-water

Use of 13N as tracer for bacterial and algal uptake of ammonium from sea-water

The dynamics of ammonia metabolism in man. Effects of liver disease and hyperammonemia.

Positron emission tomography with 2-[18F]-fluoro-2-deoxy-D-glucose in oncology

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Enzymatic Synthesis and Organ Distribution Studies with13N-Labeled L-Glutamine and L-Glutamic Acid

Cited by 69 publications

References 7 publications

Use of 13N as tracer for bacterial and algal uptake of ammonium from sea-water

Use of 13N as tracer for bacterial and algal uptake of ammonium from sea-water

The dynamics of ammonia metabolism in man. Effects of liver disease and hyperammonemia.

Positron emission tomography with 2-[18F]-fluoro-2-deoxy-D-glucose in oncology

Contact Info

Product

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Enzymatic Synthesis and Organ Distribution Studies with¹³N-Labeled L-Glutamine and L-Glutamic Acid