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Narasimhan J, Potter JL, Haas AL. Conjugation of the 15-kDa interferon-induced ubiquitin homolog is distinct from that of ubiquitin. J Biol Chem 1996; 271:324-30. [PMID: 8550581 DOI: 10.1074/jbc.271.1.324] [Citation(s) in RCA: 120] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The biological effect of type 1 interferons is proposed to arise in part from the conjugation of ubiquitin cross-reactive protein (UCRP), the ISG15 gene product, to intracellular target proteins in a process analogous to that of its sequence homolog ubiquitin, a highly conserved 8.6-kDa polypeptide whose ligation marks proteins for degradation via the 26 S proteasome. Inclusion of CoCl2 during the purification of recombinant UCRP blocks the proteolytic inactivation of the polypeptide occurring by cleavage of the carboxyl-terminal glycine dipeptide required for activation and subsequent ligation. Intact UCRP supports a low rate of ubiquitin-activating enzyme (E1)-dependent ATP:PPi exchange but fails to form a stoichiometric E1-UCRP thiol ester or undergo transfer to ubiquitin carrier protein (E2). The binding affinity of E1 for UCRP is significantly diminished relative to that of ubiquitin. These results suggest that UCRP conjugation proceeds through an enzyme pathway distinct from that of ubiquitin, at least with respect to the step of activation. This was confirmed for an in vitro conjugation assay in which 125I-UCRP could be ligated in an ATP-dependent reaction to proteins present within an A549 human lung carcinoma cell extract and could be competitively inhibited by excess unlabeled UCRP but not ubiquitin. Other results demonstrate that 125I-UCRP conjugation is significantly increased in cell extracts after 24 h of incubation in the presence of interferon-beta, consistent with the late induction of UCRP conjugating activity. Thus, interferon-responsive cells contain a pathway for UCRP ligation that is parallel but distinct from that of ubiquitin.
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Potter JL, Timmons GD, Kofron WG. Interferences by cephalosporin antibiotics in urinary tests for metabolic disorders. Clin Chem 1995. [DOI: 10.1093/clinchem/41.9.1317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Potter JL, Timmons GD, Kofron WG. Interferences by cephalosporin antibiotics in urinary tests for metabolic disorders. Clin Chem 1995; 41:1317-8. [PMID: 7544706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Potter JL, Kofron WG. Sulfadiazine/N4-acetylsulfadiazine crystalluria in a patient with the acquired immune deficiency syndrome (AIDS). Clin Chim Acta 1994; 230:221-4. [PMID: 7834873 DOI: 10.1016/0009-8981(94)90275-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Abstract
A patient with neonatal glycine encephalopathy who had severe neurologic retardation, spasticity, and seizures died at 17 years of age. Glycine concentration was markedly elevated in brain tissue, especially in the cerebellum. Neuropathologic study revealed spongy myelinopathy throughout the central nervous system and calcium oxalate crystals in the cerebellum, which are probably derived from degradation of glycine. Myelinopathy appeared to be static compared to neonatal patients. The neurologic manifestations of neonatal glycine encephalopathy are probably due to neurotransmitter abnormalities, not to myelin damage.
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Nguyen VD, Potter JL, Hersh-Schick MR. Ludwig angina: an uncommon and potentially lethal neck infection. AJNR Am J Neuroradiol 1992; 13:215-9. [PMID: 1595447 PMCID: PMC8331778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Potter JL, Sadowski L, Neal D. Evaluation of improved Ektachem chloride slides with respect to purine interference. Clin Chem 1990. [DOI: 10.1093/clinchem/36.2.386a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Potter JL, Sadowski L, Neal D. Evaluation of improved Ektachem chloride slides with respect to purine interference. Clin Chem 1990; 36:386. [PMID: 2302788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Potter JL. Acyclovir crystalluria. SCANDINAVIAN JOURNAL OF INFECTIOUS DISEASES 1989; 21:587. [PMID: 2587959 DOI: 10.3109/00365548909037891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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35
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Potter JL, Krill CE, Neal D, Kofron WG. Methemoglobinemia due to ingestion of N,N-dimethyl-p-toluidine, a component used in the fabrication of artificial fingernails. Ann Emerg Med 1988; 17:1098-100. [PMID: 3178002 DOI: 10.1016/s0196-0644(88)80455-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
An acute cyanotic episode due to methemoglobinemia occurred in a 16-month old girl following the ingestion of N,N-dimethyl-p-toluidine, a commercially available component used in the production of artificial fingernails. The amount of the parent compound ingested was about 6 mg/kg of body weight. Administration of methylene blue was effective in the reversal of the methemoglobinemia. In vitro studies suggest that the activity of the compound was probably due to its biochemical transformation to the toxic metabolite p-methylphenylhydroxylamine. We expand the list of aromatic amino or nitro compounds and their derivatives capable of producing methemoglobinemia and call attention to the hazard of their ingestion.
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Potter JL, Silvidi AA. Xanthine lithiasis, nephrocalcinosis, and renal failure in a leukemia patient treated with allopurinol. Clin Chem 1987. [DOI: 10.1093/clinchem/33.12.2314] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
An 11-year-old boy who presented in acute renal failure with significant increases of uric acid and phosphorus in his serum was discovered to have acute lymphoblastic leukemia. Five years later, he had a second and similar episode of acute renal failure, which was responsive to hemodialysis. After three months of daily therapy with allopurinol, a third and final episode of renal failure was unresponsive to peritoneal dialysis. Autopsy revealed an obstructive uropathy; focal nephrocalcinosis; and multiple, small, tan calculi in the calyces of both kidneys. Systemic cryptococcosis was also discovered. The stones, characterized by paper chromatography, electrophoresis, x-ray diffraction, and infrared spectroscopy, were 82% xanthine, 15% oxypurinol, and 3% hypoxanthine. We suggest that attention to the effects of accelerated tumor-cell lysis may protect renal function in patients with a large and drug-sensitive tumor cell load. Similarly, early detection of the fungal complications of leukemic therapy is an essential component of the treatment program.
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Potter JL, Silvidi AA. Xanthine lithiasis, nephrocalcinosis, and renal failure in a leukemia patient treated with allopurinol. Clin Chem 1987; 33:2314-6. [PMID: 3480085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
An 11-year-old boy who presented in acute renal failure with significant increases of uric acid and phosphorus in his serum was discovered to have acute lymphoblastic leukemia. Five years later, he had a second and similar episode of acute renal failure, which was responsive to hemodialysis. After three months of daily therapy with allopurinol, a third and final episode of renal failure was unresponsive to peritoneal dialysis. Autopsy revealed an obstructive uropathy; focal nephrocalcinosis; and multiple, small, tan calculi in the calyces of both kidneys. Systemic cryptococcosis was also discovered. The stones, characterized by paper chromatography, electrophoresis, x-ray diffraction, and infrared spectroscopy, were 82% xanthine, 15% oxypurinol, and 3% hypoxanthine. We suggest that attention to the effects of accelerated tumor-cell lysis may protect renal function in patients with a large and drug-sensitive tumor cell load. Similarly, early detection of the fungal complications of leukemic therapy is an essential component of the treatment program.
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Potter JL. Xanthine interference in the Kodak "Ektachem" determination of uric acid. Clin Chem 1987; 33:1265. [PMID: 3594879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Potter JL. Points: Selection of medical students by medical schools. West J Med 1986. [DOI: 10.1136/bmj.293.6546.568-i] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Agamanolis DP, Potter JL, Naito HK, Robinson HB, Kulasekaran T. Lipoprotein disorder, cirrhosis, and olivopontocerebellar degeneration in two siblings. Neurology 1986; 36:674-81. [PMID: 3703266 DOI: 10.1212/wnl.36.5.674] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Two siblings had olivopontocerebellar degeneration, failure to thrive, hepatic fatty change and cirrhosis, and a dyslipoproteinemia characterized by low cholesterol and elevated triglycerides. This condition was distinct from other cerebellar atrophies and ataxias and was not due to malabsorption or malnutrition. Cerebellar degeneration progressed rapidly during the first year of life, and both children died from intercurrent infections and surgical complications at 11 and 17 months. Stereotyped clinical and pathologic findings in the two patients suggest a previously unreported genetic metabolic disorder affecting the liver and the CNS.
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Nussbaum RL, Boggs BA, Beaudet AL, Doyle S, Potter JL, O'Brien WE. New mutation and prenatal diagnosis in ornithine transcarbamylase deficiency. Am J Hum Genet 1986; 38:149-58. [PMID: 3004207 PMCID: PMC1684765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Ornithine transcarbamylase (OTC) (E.C.2.1.3.3) is an X-linked hepatic enzyme in the urea cycle necessary for ammonia detoxification. Deficiency of OTC results in neonatal hyperammonemia, coma, and death in childhood. Because fibroblasts do not express OTC, prenatal diagnosis in the past has required fetal liver biopsy. Using a complementary DNA (cDNA) for OTC for Southern blot analysis of genomic DNA, we have found probands with complete OTC deficiency from two unrelated families in whom the same TaqI restriction endonuclease site has been altered because of independent, but not necessarily identical, mutations in the OTC gene, suggesting that this site may be a relative hotspot for mutation at a location that is critical for normal gene function. This TaqI alteration has allowed the identification of the individual in each family in whom the mutation originated as well as the exclusion of a recurrence of OTC deficiency in a male fetus at risk for the disease. OTC deficiency joins the growing list of genetic disorders for which Southern blot analysis allows accurate heterozygote detection and prenatal diagnosis in conditions for which they were not previously available.
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Lecklitner ML, Potter JL. Hepatic amebic abscess masquerading as acute cholecystitis. GASTROINTESTINAL RADIOLOGY 1985; 10:75-8. [PMID: 3882506 DOI: 10.1007/bf01893074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Hepatobiliary scintigraphy has disclosed a host of intrahepatic and extrahepatic lesions which mimic gallbladder disease. Two cases of hepatic amebic abscess are reported in which the presentations masqueraded as acute cholecystitis. Correlative, noninvasive imaging rapidly diagnosed both cases and in 1 case identified a serious complication.
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Abstract
Two diabetic patients in whom emphysematous pyelonephritis developed after renal transplantation are described. Clinical recognition of this unusual and serious infection is masked by the effects of immunosuppression. Abdominal radiographic, ultrasound, and computed tomography findings are discussed. The clinical presentation includes urinary tract infection, sepsis, and acute tubular malfunction of the allograft in insulin-dependent diabetics.
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Lecklitner ML, Potter JL, Growcock G. Computed tomography in acquired absence of thoracic pedicle. J Comput Assist Tomogr 1985; 9:395-7. [PMID: 3973174 DOI: 10.1097/00004728-198503000-00037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A patient with an acquired absence of a thoracic pedicle is presented, and the contribution of CT examination is demonstrated. A brief anatomical and radiographic review of congenital and acquired absence of pedicles is provided.
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Bova JG, Potter JL, Arevalos E, Hopens T, Goldstein HM, Radwin HM. Renal and perirenal infection: the role of computerized tomography. J Urol 1985; 133:375-8. [PMID: 3883000 DOI: 10.1016/s0022-5347(17)48982-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Predisposing factors, onset of symptoms to diagnosis interval, computerized tomography findings and the impact of computerized tomography on the outcome were studied retrospectively in 24 patients with renal or perirenal infections. The most common predisposing factors were diabetes mellitus and urinary tract calculi. The mean interval from the onset of symptoms to diagnosis was 6.8 days. The most common computerized tomography findings were thickening of Gerota's fascia, renal enlargement, focal decreased renal attenuation, perirenal fluid and focal gas. Four patients died despite early diagnosis and appropriate therapy. Computerized tomography aided in the diagnosis, assessment of the extent of disease, treatment and followup. Computerized tomography is the most direct method to evaluate patients with suspected renal or perirenal infection, although mortality may not be altered significantly.
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Flournoy JG, Potter JL, Sullivan BM, Gerza CB, Ramzy I. CT appearance of multifocal hepatic steatosis. J Comput Assist Tomogr 1984; 8:1192-4. [PMID: 6501632 DOI: 10.1097/00004728-198412000-00033] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The CT appearance of focal and diffuse fatty infiltration of the liver has been described in recent radiologic literature. Previous reports of focal steatosis have emphasized the differential diagnosis of the solitary lesion. We report a case of multifocal hepatic involvement and describe a new radiologic sign that is useful in differentiating this process from neoplasia.
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Potter JL, Shank L, Johnson D, Neal D. Interference with Ektachem 400 determinations of chloride in a leukemia patient treated with allopurinol. Clin Chem 1984; 30:1113-4. [PMID: 6586329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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50
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Potter JL, Shank L, Johnson D, Neal D. Interference with Ektachem 400 determinations of chloride in a leukemia patient treated with allopurinol. Clin Chem 1984. [DOI: 10.1093/clinchem/30.6.1113] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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