Browsing by Subject "Transaminases"

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    Enzymic imbalance in serine metabolism in human colon carcinoma and rat sarcoma
    (Springer Nature, 1988) Snell, K.; Natsumedal, Y.; Eble, J. N.; Glover, J. L.; Weber, G.; Surgery, School of Medicine
    The activities of 3-phosphoglycerate dehydrogenase, an enzyme of serine biosynthesis, and serine hydroxymethyltransferase, serine dehydratase and serine aminotransferase, which are competing enzymes of serine utilization, were assayed in human colon carcinomas from patients and in transplantable rat sarcomas. Serine dehydratase and serine aminotransferase activities were absent, whereas 3-phosphoglycerate dehydrogenase and serine hydroxymethyltransferase activities were markedly increased in both tumour types. Serine hydroxymethyltransferase catalyses the formation of glycine and methylene tetrahydrofolate which are important precursors for nucleotide biosynthesis. The observed enzymic imbalance in these tumours ensures that an increased capacity for the synthesis of serine is coupled to its utilisation for nucleotide biosynthesis as a part of the biochemical commitment to cellular replication in cancer cells. That this pattern is found in sarcomas and carcinomas, and in tumours of human and rodent origin, signifies its universal importance for the biochemistry of the cancer cell and singles it out as a potential target site for anti-cancer chemotherapy.
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    HLA-B*35:01 and Green Tea Induced Liver Injury
    (Wiley, 2021-06) Hoofnagle, Jay H.; Bonkovsky, Herbert L.; Phillips, Elizabeth J.; Li, Yi-Ju; Ahmad, Jawad; Barnhart, Huiman; Durazo, Francisco; Fontana, Robert J.; Gu, Jiezhun; Khan, Ikhlas; Kleiner, David E.; Koh, Christopher; Rockey, Don C.; Seeff, Leonard B.; Serrano, Jose; Stolz, Andrew; Tillmann, Hans L.; Vuppalanchi, Raj; Navarro, Victor J.; Medicine, School of Medicine
    Background and aims: Herbal supplements, and particularly multi-ingredient products, have become increasingly common causes of acute liver injury. Green tea is a frequent component in implicated products, but its role in liver injury is controversial. The aim of this study was to better characterize the clinical features, outcomes, and pathogenesis of green tea-associated liver injury. Approach and results: Among 1,414 patients enrolled in the U.S. Drug-Induced Liver Injury Network who underwent formal causality assessment, 40 cases (3%) were attributed to green tea, 202 to dietary supplements without green tea, and 1,142 to conventional drugs. The clinical features of green tea cases and representation of human leukocyte antigen (HLA) class I and II alleles in cases and control were analyzed in detail. Patients with green tea-associated liver injury ranged in age from 17 to 69 years (median = 40) and developed symptoms 15-448 days (median = 72) after starting the implicated agent. The liver injury was typically hepatocellular (95%) with marked serum aminotransferase elevations and only modest increases in alkaline phosphatase. Most patients were jaundiced (83%) and symptomatic (88%). The course was judged as severe in 14 patients (35%), necessitating liver transplantation in 3 (8%), but rarely resulting in chronic injury (3%). In three instances, injury recurred upon re-exposure to green tea with similar clinical features, but shorter time to onset. HLA typing revealed a high prevalence of HLA-B*35:01, found in 72% (95% confidence interval [CI], 58-87) of green tea cases, but only 15% (95% CI, 10-20) caused by other supplements and 12% (95% CI, 10-14) attributed to drugs, the latter rate being similar to population controls (11%; 95% CI, 10.5-11.5). Conclusions: Green tea-related liver injury has distinctive clinical features and close association with HLA-B*35:01, suggesting that it is idiosyncratic and immune mediated.