[Disturbed metabolism of gastric mucosa DNA precursors as prognosticator of neoplastic transformation of gastric ulcer].

Levels were assayed and compared of metabolic enzymes--thymidine and adenosine--in gastric mucosa tissues and blood serum from patients with gastric ulcer disease and gastric cancer (age--30-60 yrs). Enzymatic levels matched to the highest degree in cases of ulcer disease aggravated by chronic atrophic gastritis and precancerous alterations (dysplasia, metaplasia). Elevated concentrations of thymidine kinase and phosphorylase and adenosine desaminase were identified both at foci of ulceration (p > 0.001, p > 0.05, respectively) and in blood serum in all age brackets. Moreover, blood serum assay confirmed the view that changes in serum enzyme levels are suggestive of those in tissue enzymatic profile. Our data established a direct correlation between accumulated effect of level changes, on the one hand, and risk of neoplastic transformation of gastric mucosa in ulcer patients, on the other.

Dual-action mechanism of viramidine functioning as a prodrug and as a catabolic inhibitor for ribavirin.

An investigational nucleoside analogue drug, viramidine, has recently emerged as a potentially safer alternative to ribavirin for the treatment of hepatitis C viral infection. We have reported that viramidine mainly functions as a prodrug of ribavirin that is enriched in the liver. This in vitro study further explores viramidine's activity against nucleoside phosphorylase, a host enzyme that is responsible for phosphorolysis of ribavirin in vivo. Our experiments show that viramidine inhibits ribavirin phosphorolysis with a K(i) of 2.5 microM. This result suggests that viramidine may act through a dual-action mechanism by serving as a prodrug of ribavirin and concomitantly as an inhibitor for nucleoside phosphorylase catabolism of ribavirin.

Myocardial blood flow and flow reserve after coronary reimplantation in patients after arterial switch and ross operation.

BACKGROUND: Coronary reimplantation is used in therapy for congenital heart disease, such as in the arterial switch (ASO) and Ross operations. The adequacy of myocardial perfusion may remain a matter of concern. The aim of the present study was to stratify the effect of coronary reimplantation on myocardial perfusion and to highlight the clinical relevance of any attenuation in myocardial perfusion. METHODS AND RESULTS: A total of 21 children with transposition of the great arteries at a mean interval of 11.2+/-2.9 years after ASO and 9 adolescents at a mean interval of 4.2+/-2.1 years after the Ross procedure were investigated. All patients were asymptomatic and had a normal exercise capacity. On stress echocardiography, 2 of the ASO patients had dyskinetic areas within the left ventricular myocardium, and 5 had adenosine-induced perfusion defects on positron emission tomography. No coronary obstruction was detected on coronary angiography in any patient, but a common finding was right coronary dominance and a small caliber of the distal part of the left anterior descending artery. Coronary flow reserve (CFR) was significantly reduced in all patients after ASO when compared with 10 normal healthy volunteers (age, 25.6+/-5.3 years). CFR was normal in the 9 patients who had the Ross operation (age, 19.2+/-7.6 years); exercise-induced perfusion defects were not detected in the Ross patients. CONCLUSIONS: Children after ASO are asymptomatic, without clinical signs of coronary dysfunction. In contrast to patients who had the Ross operation, stress-induced perfusion defects and an attenuated CFR were documented. The prognostic implications of these findings and the clinical consequences are unclear; nevertheless, close clinical follow-up of ASO patients is mandatory.

[Biochemical markers of ischemic and non-ischemic myocardial damage]. / Biochemische Marker bei ischämischen und nicht ischämischen Myokardschädigungen.

BACKGROUND: Biochemical markers have been an integrative part of non-invasive diagnostic strategies in cardiology for nearly 50 years, experiencing a renascence by the recently acknowledged prognostic potential of cardiac troponins in acute coronary syndromes. DIAGNOSIS: According to the guidelines of the National Academy of Clinical Biochemistry and the International Federation of Clinical Chemistry cardiac troponin T and cardiac troponin I should be considered as the new "gold markers" of ischemic myocardial injury. One characteristic feature of these new markers is the improved diagnostic potential, reflected by the choice of two cut-off values to distinguish minor myocardial injury from acute myocardial infarction. In addition, cardiac troponins allow risk stratification in the clinical setting of acute coronary syndromes: approximately threefold higher mortality rate for patients with rest angina or ST segment elevation and cardiac troponin elevation on admission. Other indications for cardiac marker analysis are monitoring of therapeutic success in case of invasive and non-invasive reperfusion strategies and non-invasive diagnosis of non-ischemic myocardial injury (myocarditis, cardiac contusion and chemotherapy). CONCLUSION: Biochemical cardiac markers are a useful tool in the diagnosis of both ischemic and non-ischemic myocardial injury. Among these, cardiac troponins seem to become the gold markers for the new millennium.

A novel missense mutation (W797R) in the myophosphorylase gene in Spanish patients with McArdle disease.

OBJECTIVE: To investigate the degree of genetic heterogeneity of myophosphorylase deficiency (McArdle disease) in Spain through molecular studies of 10 new patients. DESIGN: The coding sequence of the entire myophosphorylase gene was sequenced in DNA extracted from muscle and blood. Restriction fragment length polymorphism analysis of polymerase chain reaction fragments was used to confirm and simplify detection of a novel mutation. SETTING: A collaborative study between 2 university laboratories in Spain and the United States. RESULTS: Five of the 10 patients harbored a novel missense mutation in exon 20, converting a tryptophan to an arginine (W797R). Three patients were homozygous for the "common" R49X mutation, and the remaining 2 patients were compound heterozygotes for R49X and a previously described missense mutation, G204S. CONCLUSIONS: The W797R missense mutation is the third novel mutation to be identified among Spanish patients. Its relative frequency suggests that it should be added to the R49X mutation in the molecular screening of McArdle disease in Spain.

Comparison of biochemical markers for the detection of minimal myocardial injury: superior sensitivity of cardiac troponin--T ELISA.

OBJECTIVES: Patients with minimal myocardial injuries who present clinically with unstable angina, early stages of myocardial infarction or myocarditis require different therapy strategies to those without. The newer diagnostic assays for detecting myocardial lesions (cardiac Troponin T and cardiac Troponin I [cTnT, cTnI], glycogenphosphorylase - BB [GPBB]) are reported to be more sensitive and specific than common biochemical markers such as CK and myoglobin. Our study tested whether the recently developed four assays cTnT-ELISA (in vitro), cTnT rapid bedside assay, cTnI rapid bedside assay, and GPBB (Immunoenzymetric assay) are effective in detecting minimal myocardial injuries caused by endomyocardial biopsy. We compared them with CK activity (CK-cat), CK-MB activity (CK-MBcat), CK-MB-concentration (CK-MB-mass) and Myoglobin concentration (Myo-conc.). PATIENTS AND METHODS: Twenty-four patients [six female, 18 male, age (mean): 47 years (20-65)] underwent diagnostic endomyocardial biopsy. Between four and six biopsies were taken from the mid-right ventricular aspect of the interventricular septum of the heart. Blood was drawn before catheterization (baseline), 10 min after the biopsy, in the next morning, and in the morning of the second day after (days 1 and 2). RESULTS AND CONCLUSION: Because of very low CKcat it was not possible to analyse CK-MBcat with reliable precision. The assay for GPBB and cTnI rapid bedside assay did not indicate this minimal myocardial injury. The CK cat, CK-MB mass, and myoglobin assays indicated significant increase at 10 min after biopsy but remained within reference range. cTnT rapid bedside assay indicated this minimal myocardial injury in 50% (P < 0.05). cTnT-ELISA (in vitro) was increased above the reference limit in 54%. This increase was 3. 6-fold the upper reference limit (P < 0.01). In our study, due to superior discriminating power, cTnT-ELISA (in vitro) was the most sensitive assay for minimal myocardial injuries.

Immunoenzymometric assay of human glycogen phosphorylase isoenzyme BB in diagnosis of ischemic myocardial injury.

With a new immunoenzymometric assay we measured human glycogen phosphorylase isoenzyme BB (GPBB) in 116 healthy individuals, 14 patients with stable angina, 107 nontraumatic chest pain patients on admission to the emergency department [45 acute myocardial infarction (AMI), 49 unstable angina, 13 other diseases], and in serial samples from 41 AMI patients. GPBB was compared with creatine kinase (CK), CKMB mass, myoglobin, and cardiac troponin T. Receiver-operating characteristic plots demonstrated the significantly greater (P < or = 0.012) discriminatory power of GPBB to detect acute ischemic coronary syndromes compared with all other tested markers. GPBB was the most sensitive marker for detection of AMI during the first 4 h after onset of chest pain, and only GPBB was increased above the upper reference limit (7 micrograms/L) on admission in patients who had unstable angina at rest and reversible ST-T alterations. This and the high early sensitivity of GPBB are most likely explained by its function as a key enzyme of glycogenolysis.

Early release of glycogen phosphorylase in patients with unstable angina and transient ST-T alterations.

OBJECTIVE: To determine whether transient ST-T alterations in patients with unstable angina are associated with an increase in plasma glycogen phosphorylase BB concentrations on admission to hospital. DESIGN: Prospective screening of patients with unstable angina for markers of myocardial cell damage. SETTING: Accident and emergency department of university hospital. PATIENTS: 48 consecutive patients admitted for angina pectoris (18 with transient ST-T alterations). None of the patients had acute myocardial infarction according to standard criteria. MAIN OUTCOME MEASURES: Creatine kinase and creatine kinase MB activities, creatine kinase MB mass concentration, and myoglobin, cardiac troponin T, and glycogen phosphorylase BB concentrations on admission. RESULTS: All variables except for creatine kinase and creatine kinase MB activities were significantly higher on admission in patients with unstable angina and transient ST-T alterations than in patients without. However, glycogen phosphorylase BB concentration was the only marker that was significantly (p = 0.0001) increased above its discriminator value in most patients (16). In the 18 patients with transient ST-T alterations creatine kinase MB mass concentration and troponin T and myoglobin concentrations were significantly (p = 0.0001) less commonly increased on admission (in five, three, and two patients, respectively). CONCLUSIONS: The early release of glycogen phosphorylase BB may help to identify high risk patients with unstable angina even on admission to an emergency department. Glycogen phosphorylase BB concentrations could help to guide decisions about patient management.

Glycogen phosphorylase isoenzyme BB mass release after coronary artery bypass grafting.

Glycogen phosphorylase isoenzyme BB mass release was studied in 20 patients undergoing coronary artery bypass grafting. In 16 patients with uneventful coronary artery bypass grafting, glycogen phosphorylase isoenzyme BB mass concentrations showed a significant, transient increase in the post cross-clamping period and decreased to baseline values within 20 hours (peak concentrations ranged from 12.7 micrograms/l to 47.5 micrograms/l, median 40 micrograms/l). One patient did not fulfil criteria for perioperative myocardial infarction, but clinical data indicated myocardial injury after aortic unclamping. In this patient only glycogen phosphorylase isoenzyme BB mass concentration and not creatine kinase isoenzyme MB catalytic concentration was increased, compared with uneventful patients. In 2 patients with emergency coronary artery bypass grafting for evolving myocardial infarction, glycogen phosphorylase isoenzyme BB mass concentrations, but not creatine kinase isoenzyme MB catalytic concentrations, correlated with clinical evidence of myocardial ischaemia. Our data indicate that glycogen phosphorylase isoenzyme BB mass concentration is a very sensitive laboratory marker of perioperative myocardial injury in patients undergoing coronary artery bypass grafting.

[Monitoring ischemia with new markers]. / Ischämiemonitoring mit neuen Markern.

The measurement of cardiac enzymes is critical for the diagnosis of acute myocardial infarction. Cardiac enzymes, however, are by no means ideal marker molecules, primarily due to their non-specific tissue distribution and low concentration in cardiomyocytes. Many limitations of cardiac enzymes can be overcome by the measurement of cardiospecific troponin T or I with immunological techniques. In the evaluation of new diagnostic methods it is important to define the purpose of marker molecule measurement, i.e., monitoring of definite myocardial infarction or establishing the proper diagnosis in patients with suspected myocardial infarction. For monitoring of success of reperfusion therapy and for the detection of reocclusion short-lived perfusion markers with rapid appearance in circulation such as myoglobin, fatty acid binding protein or glycogenisophosphorylase BB are preferable. For proper diagnosis in patients with suspected acute myocardial infarction test systems with high sensitivity and specificity are needed due to the low prevalence of disease in the patients tested. Troponin T determinations are particularly useful in this group of patients. With troponin T determinations it could be shown that some patients so far classified as having unstable angina do in fact have microinfarction. These data indicate the need for re-definition of diagnostic criteria of acute myocardial infarction.

[Action of dopamine on glucose level and glycogen phosphorylase activity of blood plasma in experimental coronary occlusion]. / Deistvie dofamina na uroven' gliukozy i glikogenfosforilaznuiu aktivnost' plazmy krovi pri éksperimental'noi koronarookkliuzii.

The effects of dopamine (5 micrograms/kg.min) on the blood plasma glucose level and glycogen-phosphorylase activity in experimental coronary occlusion were studied. The absence of the raising of the plasma glucose level and glycogen-phosphorylase "a" and "b" activities has been observed in 25 min after the coronary occlusion. It is supposed that the functional improvement of the ischemized myocardium by dopamine (5 micrograms/kg.min) is the result of the stimulation of presynaptic D-2-dopaminergic and postsynaptic D-1-dopaminergic receptors in coronary arteries.

M4 and M9 antibodies in the overlap syndrome of primary biliary cirrhosis and chronic active hepatitis: epitopes or epiphenomena?

Before the identification of the major mitochondrial antigens of primary biliary cirrhosis as components of the 2-oxo-acid dehydrogenase enzyme family, mitochondrial autoantigens were believed to be extremely heterogeneous and were divided into nine subtypes termed M1 to M9. This classification was based on the data derived from the relatively nonspecific biochemical and immunological techniques that were available. After the cloning and definition of the major autoantigens, more than 95% of the sera of patients with primary biliary cirrhosis were found to react with components of the 2-oxo-dehydrogenase enzymes; these enzymes correspond to the old M2 classification. Two other "M" species, dubbed M4 and M9, have attracted significant attention because they have been postulated to be prognostic indicators and more recently have been tentatively identified respectively as sulfite oxidase (EC 1.8.3.1) and glycogen phosphorylase (EC 2.4.1.1). Indeed, patients with the "overlap syndrome" are reported to have antibodies to M4 and a poor prognosis, whereas patients with antibodies to M9 have a favorable prognosis. To address the significance and definition of M4 and M9, we performed in-depth studies of sera from 11 patients with the overlap syndrome, 75 patients with primary biliary cirrhosis, 19 chronic active hepatitis patients, 13 patients with primary sclerosing cholangitis, 10 patients with cholangiocarcinoma, 20 patients with systemic lupus erythematosus, 20 patients with alcoholic cirrhosis, 17 patients with scleroderma and 30 normal individuals, using techniques of ELISA, complement fixation, immunoblotting and enzyme inhibition. We report herein that we were unable to show any disease-specific reactivity toward the proposed M4 and M9 antigens.(ABSTRACT TRUNCATED AT 250 WORDS)

[The determination of the glycogen phosphorylase activity in blood serum]. / Opredelenie aktivnosti glikogenfosforilazy syvorotki krovi.

A method for measuring blood serum glycogen phosphorylase (GP) activity is described, informative at early stages of myocardial infarction. The method is sensitive and available for clinical biochemistry laboratories. It consists in preliminary purification of GP from serum proteins and metabolites by affinity chromatography in micro-columns and subsequent measurement of the activity in the eluate. The procedure involves selective GP sorption on starch, washing, and subsequent desorption with glycogen solution. GP activity is measured by the kinetic spectrophotometric technique, based on enzymic measurement of glucose-1-phosphate, the product of glycogen consumption reaction, at a wavelength of 340 nm. Conditions of serum GP chromatographic purification are modified in the suggested procedure, this improving the sensitivity of the enzyme measurement. Blood serum GP activities were measured in patients with various cardiac diseases--myocardial infarction (15 cases), angina of rest and effort (53), essential hypertension (30). Different methods of GP activity measurements are considered. Recommendations on the use of the described method, a sensitive test for the diagnosis of myocardial infarction, are given.

[Base activity of glycogen phosphorylase b in human serum. Study of reference and discrimination values]. / Basalaktivität der Glycogenphosphorylase b im menschlichen Serum. Referenz- und Diskriminationswert-Studie.

Serum glycogen phosphorylase activity as one of the sensitive indicators for the diagnosis of acute heart infarction was determined at 216 healthy probands using a standardized fluorometric procedure with a detection range from 0.03 to 6 nmol/s x l serum. Basal activity was averaged at 1.22 +/- 0.39 nmol/s x l serum with a confidence interval of C.I.95 1.168 ... 1.272. Due to the estimated Gaussian distribution of the individual activity values (n = 216) the reference range was calculated from 0.5 to 2.0 nkat/l (2.5- to 97.5-percentile, respectively), the latter one being equal to the reference value of the glycogen phosphorylase activity in healthy human beings. The reference value was found to be independent of age (16-65 years) and sex. Using the discrimination value for serum glycogen phosphorylase activity at 3 nkat/l serum two groups of patients suffering either from acute myocardial infarction (n = 79) or chronic ischemic heart disease (n = 92) were separated with a diagnostic sensitivity and specificity of 0.91 and 0.93, respectively, of this diagnostic tool.

[Glycogen phosphorylase from human leukocytes. Isolation and kinetic properties]. / Glikogenfosforilaza iz leikotsitov cheloveka. Vydelenie i kineticheskie svoistva.

Homogeneous glycogen phosphorylase from human leukocytes has been obtained. A one-step bioluminescent procedure for the enzyme activity assay has been developed. This method is based on a continuous recording of the product of the glycogen phosphorylase-catalyzed reaction using a coimmobilized multienzyme system (phosphoglucomutase, glucose-6-phosphate dehydrogenase, NADH:FMN oxidoreductase and bacterial luciferase). The method sensitivity is 10 times as high compared to earlier described methods. The Km values for glycogen (0.2 mg/ml) and phosphate (3.9 mM) at pH 7.9 were determined. AMP was shown to be the enzyme effector.

Immunenzymometric assay for the heart specific glycogen phosphorylase BB in human serum using monoclonal antibodies.

An enzyme-linked immunosorbent assay for the determination of the human glycogen phosphorylase isoenzyme BB (GP BB) using two murine monoclonal antibodies was developed. A series of hybridoma clones producing monoclonal antibodies to GP BB were obtained by the standard lymphocyte hybridoma technique. Two of the selected clones synthesizing monoclonal antibodies, which recognize different epitopes, were employed for the immunenzymometric assay. The first monoclonal antibody was immobilized on microtiter plates and the bound glycogen phosphorylase BB was detected with the second monoclonal antibody conjugated with horse radish peroxidase. This assay enables a specific and sensitive measurement of GP BB in the range of 0.5-150 ng/ml phosphate-buffered saline containing 0.5% bovine serum albumin in less than 3 hours. The lower limit in human serum amounts about 3 ng/ml. Preliminary data obtained with human sera from patients after aorto-coronary artery bypass surgery are demonstrated.