Assay and the levels of 2-5A-synthetase in lymphocytes of patients with viral, bacterial and autoimmune diseases

The level of 2-5A-synthetase in extracts of peripheral blood lymphocytes was estimated by the capacity of the enzyme to synthesize 2-5A in the presence of ATP. The 2-5A was then purified on a small column of DEAE-cellulose. Here we show that under or experimental conditions, the amount of 2-5A formed is proportional to the level of the enzyme. The concentration of 2-5A (nmol of AMP/10(6) lymphocytes) in an assay therefore reflects the level of the enzyme. Enhanced levels of 2-5A synthetase were observed in the lymphocytes of patients with viral and bacterial infections. In most of the cases studied, these enhanced levels of the enzyme decreased during the course of infection parallel to recovery. Thus, the level of 2-5A synthetase may indicate the state of the disease and its evolution during the period of treatment; furthermore, it may be a useful marker in monitoring the return to a normal physiological condition. In addition to patients with viral and bacterial infections, enhanced levels of 2-5A synthetase were observed in patients suffering from autoimmune diseases. In five patients studied here, the enhanced levels of 2-5A synthetase remained high at different periods during the course of the disease. These results suggest the presence of circulating interferon throughout the disease.

[N-acetyl-cystein-(NAC)-activated creatinkinase (CK) and isoenzyme CK-MB in the serum of children]

We have examined the variation of creatinekinase levels (NAC-activated) with age in 170 children. The subjects included 40 neonates, 18 premature neonates, 40 small babies, 32 infants and 40 schoolchildren. The enzyme activity of CK-MM was very high in the first hours after delivery and remained high for a few days. The isoenzyme MB in healthy newborns also showed a higher catalytic concentration. These values (about 2-12 U/l) reached normal levels of adults within 4 months of life (0.5-5 U/l). The same rule applied to CK-MM: enzyme activities of 160 U/l and more in the first days of life declined to 16-75 U/l during the first 4 months. No correlation between birth trauma and the increase in serum-CK was found. Because of the increased CK-MM (and CK-MB) found in normal newborns screening for Duchenne-type muscular dystrophy should be postponed for a few weeks after delivery. In view of the relatively high endogenous serum CK-MB in the neonates (release of CK-MB from the skeletal muscle) the test lacks the specificity for cardiac damage. Intramuscular injections of several drugs lead to a distinct increase in CK activity. A rise of CK-MM was seen 4-24 h after catheterization of the heart.

Clearance of lactate dehydrogenase by SJL/J mice infected with lactate dehydrogenase-elevating virus

The plasma level of lactate dehydrogenase (LDH) activity rises to about ten times the normal level by 4 days after infection of mice with lactate-dehydrogenase elevating virus (LDV). The levels of seven other enzymes are also increased, but to a lesser degree. SJL/J mice demonstrate a unique, genetically controlled 20-fold increase in the plasma level of LDH enzyme after LDV infection, as well as enhanced levels of the other plasma enzymes elevated by LDV infection. Comparison of virus infection in SJL/J and Swiss mice as well as in cultures of peritoneal exudate cells made from them indicated that the time course and extent of virus replication was similar for the two strains of mice. The rate of clearance of intravenously injected rabbit or mouse LDH was found to be impaired to a similar extent in LDV-infected SJL/J and Swiss mice. The effect of LDV infection on the levels of endogenous LDH released as a result of injection of carbon tetrachloride or tumor growth was also similar in the two strains of mice. These results suggest that LDV infection may specifically induce a greater influx of LDH into the plasma of SJL/J mice from an as-yet-unknown source than in other strains of mice.

Role of glucose homeostatic mechanisms in viral infections

Though normoglycaemia is thought to indicate adequacy of cellular glucose content, ketoacidosis occurs in viral infections even in the presence of normo- and hyperglycaemia. These wide variations in glucose concentrations may reflect the patients' adaptive abilities in situations where glucose transport is impaired by viruses. Hypoglycaemia would suggest poor adaptation and hyperglycaemia good adaptation. Increased free fatty acid (FFA) concentrations and enzyme activity are probable adaptive mechanisms. If so, they should decrease with hyperglycaemia-producing infusions. Profiles of glucose, FFA, enzymes, and fever over 19 days in 24 children with viral infections are reported. On admission 87.5% were normo- or hyperglycaemic with increased FFA, AST, LDH, and fever (P less than 0.005) when compared with values 19 days later. With infusions that produced hyperglycaemia, there was clinical recovery with a decrease in FFA and enzyme activity. The hyperglycaemia observed in 56.5% therefore points to glucose homeostatic mechanisms being geared to maintain the intracellular milieu. Hence normoglycaemia does not always indicate cellular glucose adequacy.

Particle-bound DNA polymerase activity in haematological disorders and normal controls

A DNA polymerase present in particles with a density greater than 1.20 g/cm3 and capable of using a synthetic RNA template has been sought in human malignancies. This report deals with a study of a great number of peripheral-blood samples from normal controls and patients with malignant and non-neoplastic haematological disorders. For screening purposes a simplified detection test was used. In 63 controls low levels of enzyme activity were found. The enzyme activities showed a biphasic distribution pattern. Three out of 53 patients with non-neoplastic, miscellaneous haematological disorders had an elevated enzyme level associated with active viral infections (hepatitis, mononucleosis infectiosa). In 128 patients suffering from haematological malignancies 18 out of 21 cases of elevated enzyme level were associated with the presence of more than 10% pathological cells in the white blood cell fraction.

Variation of (2'-5') oligo A synthetase level in lymphocytes and granulocytes of patients with viral infections and leukemia

Using a simplified technique for the determination of oligoisoadenylate synthetase activity, we have compared the cellular level of this interferon (IFN)-induced enzyme in multiple samples of peripheral blood leukocytes. In mononuclear cells (PBMC) of healthy donors the enzyme level was remarkably constant, but in the cells of about 85% of patients with viral infections enzyme activity was significantly elevated. In contrast, the incidence of elevated activity in bacterial infections was low. Synthetase activity could be also detected in granulocytes, although normally its level in these cells was considerably lower than in PBMC. A sharp increase in the enzyme level in granulocytes was found in cells exposed in vitro to IFN, as well as in cells from patients undergoing IFN therapy. Increased synthetase activity was also detected in the granulocytes of patients with viral infections. We have also determined the level of the enzyme in patients with various types of leukemias. In a large proportion of the patients with acute lymphoblastic leukemia (ALL) we found severely decreased enzyme levels (10-20% of control value). The decreased activity could usually be correlated to predominance of blast cells in the peripheral blood.

Comparison of (2'-5') oligo-adenylate synthetase and interferon blood-levels in mice early after viral infection

The level of the IFN-induced enzyme (2'-5') oligo A synthetase in the peripheral blood mononuclear cells (PBMC) was determined in mice at different times following virus infection. There was a significant increase (4-7-fold) of the enzyme level within less than 12 h after i.p. injection of either VSV (10(7) pfu) or Sindbis virus (2.10(4) pfu). The elevated level was maintained for about a week and then the activity returned to normal. There was, however, a marked difference in the pattern of serum level of IFN during infection by the two viruses; while in the mice infected by VSV, serum IFN was very high on the first day and declined to an undetectable level by the fourth day, in the mice infected with Sindbis virus, serum IFN was barely detectable at the first day and then increased towards the fourth day of infection. Antiviral antibodies could be detected in the serum only about a week after infection. We conclude that viral infection can result in a rapid elevation of (2'-5') oligo A synthetase in the PBMC, even when serum IFN remains low. Thus, quantitation of the enzyme level can be a useful diagnostic aid in viral infection particularly in the early stages and in cases in which antiviral antibodies and IFN can not be detected.

Activity of some enzymes involved in "adenylate cycle" in rat embryo cells infected with parvoviruses (X14, H-1)

In rat embryo cell cultures infected with X14 or H-1 parvovirus and in mock-infected cell cultures the activity of some enzymes involved in purine nucleotide interconversion and in "adenylate cycle" was determined. The enzymatic activities have been assayed on 100,000 x g supernatant by spectrophotometric methods, measuring the absorbance variation in U.V. and by radiometric methods, resolving the radioactive products of reaction by TLC on PEI cellulose. The results indicated a decrease of the enzymatic activities that degrade purine nucleosides and nucleotides in infected cells compared to the controls. Some different behaviour patterns showed the enzymes involved in base salvage pathway; adenine phosphoribosyltransferase did not show a significant modification of activity, whereas hypoxanthine (guanine) phosphoribosyltransferase increased slightly in X14 virus-infected cells. The behaviour of the above mentioned enzymatic activities may be considered as a mechanism of purine nucleotide saving, coupled to an active salvage pathway for the synthesis of nucleotides required for the viral replication.

Skeletal muscle lactate dehydrogenase isozymes and fibre composition in viral, mycoplasma and bacterial infections in young and old men

The activities of LD isozymes were studied by thermoinactivation in skeletal muscle biopsies from young and old patients suffering from viral, mycoplasma or bacterial infections and from corresponding controls. The activities of LD2-5 decreased 35-45% and that of LD1 17-29% in the muscle of the patients compared to that of the controls. There were no differences between age groups. In the controls good correlations were demonstrated between the relative activities of the LD isozymes and the muscle fibre composition, but such correlations could not be found in the patients. This indicates that the decrease of the activity of muscle LD in these infections is not associated with alterations in any specific muscle fibre type but rather with an effect of a general reduction of the LD activity.

[Comparative characteristics of the activity of lysosomal proteinases in in transplantable cell cultures susceptible and resistant to a specific group of viruses]

Institute of Nutrition, Academy of Medical Sciences of the USSR, Moscow Directed change of the genotype in cell cultures (Hela, fibroblasts, L929), which leads to the resistance to challenge with some of the viruses is accompanied by pronounced modulation of the activity of lysosomal proteinases, cathepsins A, B1, D and, in the first turn, by a considerable reduction (by 2--12 times) of cathepsin C activity. The data obtained indicate an important role of the proteolytic system of the cell lysosomal apparatus in providing defence reactions.

Antiviral drugs: modes of action and strategies for therapy

The understanding of viral metabolism, particularly the molecular basis of enzyme interactions governing replication of viruses, is one of the basic challenges in the relatively new field of antiviral chemotherapy. Although a few agents have shown documented efficacy and safety in the treatment of influenza A and herpes simplex infections, the search through myriad antiviral candidates continues.

Serum immunoreactive trypsin concentrations in infectious and non-infectious illnesses and in juvenile diabetes

Serum immunoreactive trypsin (SIT) concentrations were measured in 244 patients with infectious illnesses and in 281 children with diabetes of recent onset. Results were compared with reference ranges established in 107 patients with non-infectious, non-diabetic illnesses, in whom SIT concentrations were found to increase with advancing age. Reduced or undetectable concentrations of SIT were associated with diabetes in children and with a few cases of severe childhood infection. Increased SIT concentrations were associated with virologically confirmed cases of infection with mumps and Coxsackie B virus infection, and with clinical diagnoses of mumps, PUO, and meningitis in children, and with Bornholm disease, cardiac infection, and respiratory infection in adults. It is suggested that silent invasion of the exocrine pancreas with elevation of the SIT concentration may accompany infection by Coxsackie B, mumps, and, possibly, other viruses.

Changes in oxygen radical scavenging by human blood cell lysates concurrent with viral infections

The higher superoxide dismutase (SOD) levels found in human blood cells when Nitro Blue Tetrazolium (NBT) rather than Cytochrome C was used as the colorimetric detector of superoxide (O-2) was investigated. the NBT was found to react with oxygen radicals other than O-2, thus providing measurement of total oxygen radical scavenging ability. Also investigated was the biomodal distribution of SOD activity in lymphocytes and granulocytes from a randomly selected human populace. Human lymphocytes rapidly increased their SOD activity by two- to four-fold during respiratory viral distress. The response to certain infections was probably responsible for the bimodal distribution of SOD activity in the general populace. It was concluded that the chemical events that prepare lymphocytes and granulocytes for their role in defense against infections begin long before these cells are sequestered from circulation by the infections.

[Serum activity of leucine aminopeptidase in lymphotropic infections and in malignant lymphomas]

Increases of the leucine aminopeptidase according to data of literature are regarded as a sensitive parameter of lesions in liver diseases. In patients with active generalised lymphadenitis (viral infections, toxoplasmosis) as a typical enzyme constellation a relatively strong leucine aminopeptidase increase in the serum with missing or relatively slight enzyme deviation of the transaminases could be found. The quotient of the activities of LAP/ALAT was clearly above that of inflammatory liver diseases. In chronic lymphatic leukosis, plasmocytoma and malignant lymphomas the leucine aminopeptidase serum activities were within the normal. Increases of leucine aminopeptidase in lymphotropic infections are probably partly of extrahepatic origin.

Structural and functional abnormalities of the small intestine in infants and young children with rotavirus enteritis

Structural and functional alterations in duodenal mucosa from 17 children with rotavirus enteritis were assessed. Structural changes were found in specimens from all patients. Patients with the most severe mucosal damage were more likely to require intravenous therapy to correct dehydration. Depression of one or more mucosal disaccharidases was found in 14 of 16 patients. Repeat duodenal biopsy three to eight weeks later in six patients showed marked improvement. The study clearly shows that rotavirus can cause a marked structural and functional lesion in the upper small intestine which is rapidly reversible.

Superoxide dismutase and glutathione peroxidase in polymorphonuclear leucocytes

Superoxide dismutase (SOD) and glutathione peroxidase (GPX) protect aerobic organisms against the toxic superoxide anion and hydrogen peroxide, which are generated during phagocytosis by polymorphonuclear leucocytes (PMNs). PMNs of children with bacterial infections and with infectious hepatitis contained significantly elevated SOD activity, whereas GPX activity remained in the normal range. In contrast, PMNs of children with viral infections and rheumatoid arthritis exhibited a decreased SOD activity, while GPX activity was again unchanged. The children's age, sex or treatment did not effect the enzyme activities in PMNs. Since SOD generates bactericidal hydrogen peroxide and regulates the release of the toxic superoxide radical into the surrounding tissues, this study may add new understanding to the pathophysiological aspects of acute and chronic inflammatory processes.