Search

The haematological data in a 9-year-old Dutch child suffering from an unusual new variant of glucose-6-phosphate isomerase deficiency (GPI Utrecht) are discussed. Symptoms and signs differ in many respects from those generally observed in GPI deficiency, as mental retardation, drug sensitivity and increased susceptibility to infections were present. Extensive studies on mechanisms involved in drug-sensitive haemolytic anaemia did not reveal its causes. Though the defect was generalized, no disturbance in granulocyte and thrombocyte functions were detected.

Serum concentrations of lactate dehydrogenase (LDH), alpha-hydroxybutyrate dehydrogenase (HBD), phosphohexose isomerase (PHI), leucine aminopeptidase (LAP), beta-glucuronidase (beta-gluc) and angiotensin-converting enzyme (ACE), were measured in 107 cases of untreated acute myeloid leukaemia which were classified by morphological, immunological and cytochemical criteria. The results show that serum LDH was increased in most cases, irrespective of leukaemic subtype, serum PHI and LAP were significantly higher in monocytic variants and serum beta-gluc and ACE levels were generally within normal limits. In addition, significant (p less than 0.05) relationships were found between serum LDH, PHI, LAP and beta-gluc concentrations and the numbers of circulating leucocytes.

Plasma carcinoembryonic antigen (CEA) and serum enzyme levels of phosphohexose isomerase (PHI), gamma-glutamyl transpeptidase (psi-GTP), and lactate dehydrogenase (LDH) were measured in 147 patients with malignancy. Levels were higher in patients (particularly with G.I., breast and lung cancers) than in normals or in patients with cancer in clinical remission. Elevations of CEA and of all three enzymes in blood were most frequent in patients with hepatic metastases. CEA elevations correlated directly with PHI levels. Seventy-eight percent of patients with metastatic G.I. cancer could be identified by CEA (greater than 5 ng/ml) alone, as well as 38% with breast cancer and 85% with lung cancer; but only 17% of other cancers could be identified by CEA alone. CEA or one or more enzymes was elevated in 64% of metastatic breast cancer patients, 92% of lung cancer and 41% of other cancers, but enzyme measurement did not increase identification of G.I. cancer over that achieved by CEA alone. These findings suggest that circulating levels of CEA, PHI, psi-GTP and LDH may reflect a direct contribution from the malignant tissue and/or liver malfunction secondary to liver replacement.

The phosphohexose isomerase (PHI) activity was measured in parotid and submandibular saliva of patients suffering from chronic sialadenitis and of healthy control persons. In control persons the mean PHI value determined in parotid saliva (10.93 +/- 1.17 U/l) was significantly lower compared to that measured in submandibular saliva (38.18 +/- 4.44 U/l). In chronic sialadenitis the salivary PHI activity was significantly increased and reached values up to 5440 U/l in parotid secretion and values up to 1620 U/l in submandibular secretion. The possible role of salivary PHI activity as a parameter for the diagnosis of chronic sialadenitis is discussed.

We describe a prototype system for preparing multiple fractions of blood components (plasma, washed erythrocytes, and hemolysates) by use of automated techniques. The procedure is based on centrifugal separation and sample transfer by induced pressure differentials in a blood-processing vessel (rotor) that has been designed to process 24 samples simultaneously. Erythrocytes are sedimented against the outer walls of individual sample chambers, and plasma is siphoned, by imposition of either a slight positive or negative pressure, into individual reservoirs in a collection ring. Cells are washed in situ; samples of washed cells, either packed or in saline solution, can be recovered. Cellular hemolysates are automatically prepared and transferred to individual, commercially available collection vials, ready for immediate analysis or for storage in liquid nitrogen. The system has potential application in any biomedical area in which many samples are to be expeditiously analyzed and in which one or more of the blood fractions will be used. A separate unit has been designed and developed for the semiautomated cleaning of the rotor.

An electrophoretic survey of 13 enzymes corresponding to 19 loci has been carried out in Belgian Landrace and Pietrain pig breeds. Four of these enzymes have been shown to exhibit electrophoretically detectable polymorphism. The average heterozygosity per locus was found to be 0.066 in the Belgian Landrace and 0.028 in the Pietrain pigs.

Two types of glucosephosphate isomerase (GPI) are described for the first time in sheep. Type T produced a 3-band pattern on polyacrylamide gel electrophoresis of serum samples, whereas type M produced a pattern of 5-7 bands. When 23 Scottish Halfbred ewes showing type T were mated to 3 Suffolk rams showing type M, their 32 offspring had frequencies of 0.72 and 0.28 for T and M respectively. There was no conclusive evidence that the types were controlled by codominant alleles or by simple Mendelian inheritance and neither was sex-linked. The frequency of the rarer type (M) was sufficiently high to provide conclusive evidence of true enzyme polymorphism.

In hypernephroma an overall diagnostic sensitivity of 72% and a specificity of 87% was found for the serum tumor marker phosphohexose isomerase (PHI). Both in early stage disease and in well differentiated tumors a sensitivity of about 60% was reached. In contrast the sensitivity of three other glycolytic enzymes tested was found to be less than 20%. Since the cancer induced elevation of PHI activity in the tumor was found to be comparable to those of the other test enzymes, elevated PHI serum activities cannot be attributed to overproportional PHI synthesis and unspecific cell-lysis. In 6 of 10 cases studied differences in the PHI isozyme pattern between the tumor and the normal tissue were found suggesting the occurrence of cancer associated structural alterations of PHI.

This article is concerned with a prospective study about the systematical, simultaneous and comparative assay of four biological markers (carcino-embryonic antigen, lactate dehydrogenase, gammaglutamyl transferase and phosphohexose isomerase). This study was conducted in a department of Hematology and oncology on 258 patients. The dosage of each marker separately does not appear to be of diagnostical interest because of a lack of sensibility and specificity. But when there is a positive statistical correlation between several makers, their simultaneous dosage may allow the diagnostic of cancer and sometimes the determination of its origin.

Infection of mice with Friend erythroleukemia virus initially causes massive proliferation of erythroid precursors accompanied by splenomegaly and reticulocytosis. Strains of mice differ among themselves in susceptibility to Friend virus and one of the major genes affecting the early response to viral infection is Fv-2. Allophenic mice compounded from a resistant strain C57BL/6 (Fv-2rr) and a susceptible one DBA/2 (Fv-2ss) were infected with the polycythemic strain of Friend virus to determine whether susceptibility/resistance was limited to cells of the respective genotypes or if there was an influence across the genotypic barriers. The manifestations of viral pathogenesis monitored were splenomegaly, reticulocytosis and leukocytosis. In addition, the proportion of red cells of the two genotypes in each animal was monitored before and after viral infection by analyses for strain specific electrophoretic variants of hemoglobin and glucose phosphate isomerase. The group of allophenic mice with 25% or more susceptible-strain red blood cells all developed symptoms of virus-induced disease and also revealed dramatic increases in the number of red cells of the susceptible-strain genotype. Thus, no evidence for protection of susceptible-strain cells by ones of the resistant strain could be observed and the disease developed primarily in susceptible strain cells. On the other hand infected animals with 15% or less DBA/2 red cells were severely retarded in the development of Friend disease. Under these circumstances susceptible strain target cells might fail to undergo viral induced replication as a result of direct protection by resistant strain cells. Alternatively, other more complex mechanisms might be involved such as protective anti-viral immune reactions.

This paper presents the results of an electrophoretic survey of approximately 4000 individuals from Hiroshima and Nagasaki for four erythrocyte enzymes: isocitrate dehydrogenase, peptidase A, peptidase B, and phosphohexose isomerase. Also reported are the results for erythrocyte acid phosphatase for a subset of these individuals. The frequencies for the ACPA1 and ACPB1 alleles of the ACP1 locus are in agreement with previously reported results from Japanese populations. Rare variants of ICDS, PEPA, PEPB and PHI occur with frequencies varying from 0.25 to 7.2 per 1000 determinations. The relatively high frequency of the PHI 4HIR1 variant and some unusual features involving the effect of reducing agent on the electrophoretic pattern behaviour of some of the rare PHI variants detected during this study are discussed.

A new case of glucosephosphate isomerase deficiency with mild haemolytic anaemia was observed in a 6-year-old girl. Deficient enzyme was characterized by a profoundly decreased activity in the red cells, a normal electrophoretic phenotype, normal isoelectric point, normal optimum pH, a molecular instability and a clearly decreased Michaelis constant for fructose-6-phosphate. Propositus was double heterozygote for a 'silent gene' inherited from the mother and an abnormal enzyme from the father. Because this abnormal enzyme has undescribed characteristics, it responds to a new variant for which we propose the name GPI-MYTHO.

Enzyme activity declines with erythrocyte age in most mammals. To test this concept in the dog, we decreased the PCV to less than 20 by phlebotomy. The erythrocytes were restored rapidly (1.57 per cent per day). The resulting decline in the mean erythrocyte age was accompanied by increased activity by most of the erythrocyte enzymes studied. Enzymes with lower initial enzymatic activity (hexokinase, pyruvate kinase, 6-phosphogluconate dehydrogenase and glutathione reductase) increased proportionally more than those with higher initial activity (lactate dehydrogenase, 3-phosphoglycerate kinase, glyceraldehyde-3-dehydrogenase and glucose-6-dehydrogenase). Among species, increases in enzyme activity after phlebotomy appear to be related to each species' life span. Most of the metabolites increased concomitantly with the highest reticulocyte period. Diphosphoglycerate concentrations did not change significantly during the experiment.

Rabbit erythrocytes were separated by centrifugation on a discontinuous Percoll gradient into fractions of progressively increasing cell age to measure the in vivo decline in catalytic activity of eleven enzymes during the erythrocyte life span. Erythrocyte enzymes decline exponentially at different rates. The maximal and minimal catalytic activities (erythrocyte catalytic activity at the beginning and at the end of the erythrocyte life span), the intracellular half-life of enzymes and the daily loss of catalytic activity of total body erythrocytes were estimated.

Serum phosphohexose isomerase (PHI) levels were estimated in 28 patients with head and neck cancer. The mean value was significantly higher when compared to the controls. There was no difference in mean PHI value with respect to the character of the lesion or with the histopathological type of growth. The activity was increased with the advancement of the stage of cancer. With radiotherapy, a gradual and significant decrease in serum PHI activity was observed.

The Authors have tested serum levels of alpha-1-antitrypsin (A1AT), phosphohexose-isomerase (GPI) and carcinoembryonic antigen (CEA) in 133 patients affected with primary lung cancer, not treated with any drug, and in 183 patients affected with not neoplastic lung diseases or healthy, to control the utility of these markers in the early diagnosis of lung cancer. In many patients all the tests have been made at the same time. The three tumoral markers have been also examined in connection with the histological kinds of lung cancer. Results show that is suitable to test GIP and A1AT at the same time because they are percentually more pathological; serum levels of CEA, that are not very elevated in the pathological cases, seem in correlation with the histological kind of cancer.

The AA. have tested serum levels of ferritin, alpha-1-antitripsyn, C4 and Phosphohexoseisomerase (PHI) in 50 patients affected by primary lung cancer, 40 patients affected by chronic lung diseases and a control group of 40 healthy males and females. All the test have a percentage of pathological case higher in the group of neoplasms than in the group of chronic diseases and ferritin seems to have the highest sensitivity. Obtained results have been correlated also to the morphoradiological and histological kind of neoplasm. "Peripheral" morphoradiological kind and III WHO histological kind are the group with more pathological cases. All the data have been statistically controlled.

A congenital erythrocyte pyruvate kinase (PK) deficiency was found in a 72-year old female patient with chronic myelomonocytic leukemia (CMML). Erythrocyte PK deficiency was associated with an increase in the activity of hexokinase, 6-phosphogluconate dehydrogenase and glutathione peroxidase in erythrocytes as well as a decrease in acetylcholinesterase, glutathione reductase and glucosephosphate isomerase activities. The enzymatic abnormalities were accompanied by alterations in hemoglobin and in i antigen content of erythrocyte membrane. In addition, bone marrow ultrastructural studies showed dyshemopoietic changes in all blood cell lines and especially in erythroblasts. The present findings confirm the close relationship between CMML and acquired dyserythropoietic syndromes and constitute a new observation of the infrequent association of hereditary erythrocyte enzymopathies and leukemia. A survey of the literature is presented.

A total of nearly 300 persons belonging to the Savara and Jatapu tribes in the Srikakulum District of northern Andhra Pradesh have been tested for electrophoretic variation in 13 red cell enzyme systems, and also haemoglobin. The gene frequencies for the systems showing variation are within the range for other South Indian populations, and there are no significant differences between the two tribal groups investigated in this report except in the case of adenylate kinase. The Jatapu (along with the Kadar of Kerala) have the highest frequency of AK1 so far reported in India. Both the Savara and Jatapu showed a low frequency for Hb AS, and LDH-Calcutta 1 was not detected in either population.

Serum levels of phosphoexose isomerase (PHI) were determined in 138 cancer patients. The enzyme levels showed a relation to the clinical stage of the tumor, and were, on the average, higher in advanced disease. The behavior of the enzyme levels after chemotherapy and/or radiotherapy was studied in relation to the clinical response. A statistically significant reduction of PHI activity in patients with subjective and objective or only subjective responses to therapy was noted. The mean values before and after chemotherapy in patients with progression of the disease were not significantly different. The authors conclude that high levels of serum PHI are, most often, associated with an advanced and/or a metastasized tumor; furthermore PHI seems to be a reliable biologic marker of the destruction of cancer tissue.

Red cell enzymes, 2,3-diphosphoglycerate (2,3-DPG) and adenosine triphosphate (ATP), were evaluated in a 23-mo-old boy with juvenile chronic myelocytic leukemia (JCML) at the onset of his illness and 6 mo later during the accelerated phase. The activities of the age-dependent red cell enzymes, hexokinase, aldolase, pyruvate kinase, and glucose-6-phosphate dehydrogenase, were elevated, as were the concentrations of red cell 2,3-DPG and ATP, consistent with a young red cell population metabolizing at an increased glycolytic rate. The activities of the non-age-dependent enzymes, glyceraldehyde-3-phosphate dehydrogenase (G3PD), phosphoglycerate kinase, and enolase, were also increased to levels similar to or greater than those observed in term infants. As the illness progressed, the activity of red cell G3PD increased further, and phosphoglucose isomerase activity increased markedly. These results are consistent with the prior suggestion that JCML represents a reversion to "fetal" erythropoiesis.

The results of a preliminary study on the serous level of PHI in patients undergoing treatment at the Catania Oncology Institute are reported. Of 53 subjects with ongoing cancer, higher than normal values were encountered in 70% of cases. This percentage rose to 82.3% in cancer patients with metastasis affecting the skeleton. Of 12 subjects who underwent mastectomy with no clinical signs of recurrence only three showed abnormal values while in no case of fibrocystic mastopathy were levels higher than normal observed. A constant correlation was identified between effectiveness of surgical, radiotherapeutical or medical treatment and reduction in serous level of PHI. The usefulness of this investigation in oncology is thus confirmed.

Some enzymes of glycolysis and tissue respiratory were studied in 377 patients with chronic circulatory insufficiency developing due to atherosclerotic cardiosclerosis and rheumatic heart diseases. The severity of hyperenzymia was found to grow along with the increasing stages of circulatory insufficiency. A direct correlation was established between the total activity of LDH and MDH, as well as between LDH5 and MDH1. The presence of enzymatic shifts in patients with haemodynamic disorders permitted to include, with good substantiation and differentiation, such drugs into the complex therapy that favourably effect the disturbed metabolic processes.

Several enzyme polymorphisms and hemoglobin variants were typed in a sample of n = 219 non-related Greek blood-donors. The following gene frequencies were observed: pa = 0.201, pb = 0.701, pc = 0.098;PGDA = 0.985, PGDc = 0.015; AK1 = 0.942, AK2 = 0.058; HbA = 0.988, HbS = 0.012. No polymorphic variation was seen in LDH, s-MDH, PHI, or SOD. The population genetical aspects of these results are discussed.

Analysis of C57BL/6J in equilibrium A/J allophenic mice for their lymphocyte composition, using H-2 antigens as external markers, and glucose phosphate isomerase (GPI) isozymes as internal markers, has led to the discovery of two unusual mice. Both mice showed heterodimers of GPI isozymes upon electrophoresis of the lymphocyte lysate. Specific anti-H-2 antisera confirmed that the cells of the mice were of C57BL/6J and A/J origin, as expected, but that the "A/J" cells seemed to behave as F1 hybrids containing the Gpi-1a and Gpi-1b alleles. Possible origins of the Gpi-1b allele in the "A/J" cells are discussed.

The normal range of glucose-phosphate-isomerase (GPI) in the plasma of children during the first month of life is up to 80 U/l; until the end of the second year of life between 11 and 50 U/l; thereafter the upper limit is 46 U/l. In osteogenic sarcoma or medulloblastoma there is a good correlation between activity of GPI in plasma and clinical tumor stage. In a lot of other tumors sensitivity of this enzyme is either very low as in Ewing-sarcoma or myeloic leukemia or there is no consistent relation to the extent of the tumor. High activities of GPI are equally obtained in children suffering from cystic fibrosis, diabetes mellitus or muscular dystrophy. GPI is not valid as a tumor marker even being raised in sarcoma and medulloblastoma as mentioned. So it is not necessary to check GPI activity as a part of routine enzyme chemistry.

The authors describe simple and rapid separation technics by electrophoresis on cellulose acetate of glucose-6-phosphate dehydrogenase isoenzymes, 6-phosphogluconate dehydrogenase, phosphoglucomutase, adenosine deaminase, adenylate kinase, phosphohexose isomerase, lactate dehydrogenase iosenzymes in the red cells. These technics are derived from those of Rattazi et al. for glucose-6-phosphate dehydrogenase and Sonneborn for 6-phosphogluconate dehycrogenase, phosphoglucomutase, adenosine deaminase, adenylate kinase and acid phosphatase.

The purpose of this study was to compare the diagnostic significance of serum tumor markers in metastatic breast cancer and to evaluate their usefulness in monitoring palliative treatment. One hundred sixty-two breast cancer patients with various disease involvement have been followed-up by serum beta-human chorionic gonadotrophin (beta-HCG), alkaline phosphatase (AP), phosphohexose isomerase (PHI), carcinoembryonic antigen (CEA), and tissue polypeptide antigen (TPA) analysis for 6 to 29 months. In metastatic disease, rates of elevated tumor marker levels ranging between 44% and 91% were found except for beta-HCG (13%). The low rate of positive beta-HCG values did not suggest that routine estimation may be useful. For the other markers, differences in positive rates were seen when site of metastasis, tumor burden, tumor activity, and stage of disease were taken into account. CEA and TPA were shown to be more sensitive indicators for metastatic disease than AP and PHI. TPA was more sensitive but less specific than CEA; both provided almost identical discrimination. In monitoring palliative treatment, a close correlation was found between the clinical course and changes of CEA. AP and PHI frequently became elevated only in very advanced disease, their elevation supported the clinical evidence of progression.

Determinations of erythrocyte enzyme scavengers of oxygen radicals (glutathione-peroxidase, superoxide-dismutase and catalase) and determinations of erythrocyte age-dependent glycolytic activities (glucose-6-phosphate-dehydrogenase, pyruvate-kinase and glucose-phosphate-isomerase) were carried out in cord blood and in the blood taken on the 4th day of life in 152 newborn infants with different peak bilirubin levels. The enzyme activities scavenging oxygen radicals, glutathione-peroxidase and superoxide-dismutase were significantly lower in infants with peak bilirubinemia higher than 214 mumol/l, compared to less-jaundiced neonates, both at birth and on the 4th day of life; their values correlated negatively with peak bilirubinemia at birth and on the 4th day of life. Glycolytic age-dependent enzyme activities were significantly higher in more jaundiced newborn infants only on the 4th day of life, when their values correlated positively with peak bilirubinemia. The results of this investigation suggest that a deficiency of factors protecting from oxygen toxicity, may play a role in the development of neonatal hemolysis and jaundice.

The activity of blood glucose phosphate isomerase (GPI-1) in mice heterozygous for various alleles at the Gpi-1s structural locus (heterozygotes a/b, a/c and b/c) was significantly higher than expected, on the basis of additive inheritance, from the levels in parental homozygotes. Moreover, the GPI-1 activity was higher in a/b heterozygotes than in either parent (heterosis). Studies of heat stability with kidney homogenates revealed that the relative stabilities of GPI-1 dimers was AA greater than AB greater than BB greater than AC greater than or equal to BC greater than CC. Differences in dimer stabilities in vivo would affect the total GPI-1 levels in heterozygotes and could account for non-additive inheritance but would be insufficient to explain heterosis for GPI-1 activity. Other possible contributing factors include unequal production or stability of monomers, or higher catalytic activity of heterodimers. Monomers could also associate non-randomly but this would not be sufficient to explain heterosis. It is clear that non-additive inheritance patterns may be produced by variants of either structural or regulatory genes.

Frequency of blood group factors at the A-O and H loci were markedly altered within halothane positive (HP) and halothane negative (HN) composite synthetic Pietrain/Hampshire lines (PTH) over four generations of selection. Linkage studies on the litters from 45 double backcross and 20 mixed and intercross matings, involving the S(A-O), H, Phi and Hal loci, were made in the PTH line and halothane positive and negative selected British Landrace lines. Crossing-over frequencies of 0.05 +/- 0.04, 0.05 +/- 0.03 and 0.1 +/- 0.03 were established between Phi and Hal, H and Hal, and Phi and H respectively. An unequal crossing-over frequency between Phi and H was found when the alleles Ha and Hcd were compared. The difference in recombination frequency between the Ha and Hcd alleles amounted to 0.04 to 0.06. No cross-overs were observed between the S(A-O) and Phi, H or Hal loci in 15 families studied. The position of the S locus in relation to the other loci could not be established, but statistical evidence of association favours a haplotype sequence of Phi-Hal-S-H.

Associations between production traits and the genes for halothane sensitivity (HAL), S, A and H blood group systems and phosphohexose isomerase (PHI) and 6-phosphogluconate dehydrogenase (6-PGD) enzyme systems were investigated in two lines of pigs selected for an index. The phenotypic variance-covariance matrix of the index included backfat thickness and daily gain, whereas the genetic variance-covariance matrix included daily gain, feed conversion and percentage of lean meat. The experiment was conducted at the experimental station of the Institute of Animal Production and has been underway since 1973. The same index was applied but in two opposite directions to give a superior and inferior line in relation to the production traits. One hundred twenty-nine animals of the superior line in the seventh generation and 88 animals of the inferior line in the sixth generation were studied. Forty-two percent (54/129) of the animals of the superior line were halothane-positive. No animals in the inferior line were halothane reactors. Of the halothane-positive pigs, 70.4% (38/54) in the superior line had the HaHa and 94.4% (51/54) had the SsSs genotype, whereas only 4% (3/75) of the HaHa and 12% (9/75) of the SsSs pigs were halothane-negative. By practicing selection at the H and S loci, it seems possible to efficiently reduce halothane sensitivity in Swiss Landrace pigs. In pigs of the superior line, there were significant differences in percentage of lean meat, carcass length, pH1 (pH value at 45 min to 1 h postmortem, M. longissimus) and reflectance values among genotypes of the HAL, S and H systems and among some genotypes of the 6-PGD system. Poorest meat quality, highest percentage of lean meat and shortest carcass length were observed in pigs homozygous for the alleles HALn, Ss, Ha, PHIB and 6-PGDA. In the inferior line, these associations were absent. As the HAL locus is associated with the above mentioned production traits, linkage disequilibria may explain the observed associations among the H, S, PHI and 6-PGD types and production traits.

The purpose of this study was to compare the diagnostic significance of serum tumor markers in patients with gynecological malignancies and to evaluate the usefulness of the markers in the follow-up after primary treatment. Determined were tissue polypeptide antigen (TPA), carcinoembryonic antigen (CEA), and phosphohexose isomerase (PHI). Serum samples from 200 patients with cervical cancer, 206 patients with endometrial cancer, and 254 patients with ovarian cancer were analyzed. With regard to specificity, CEA and PHI exhibited false positive rates below 10% in normal controls (N = 96). For TPA, the same result was obtained only by using 120 U/l as a cut-off level. As for sensitivity, positive rates above 50% prior to therapy were demonstrated by PHI and TPA in ovarian cancer as well as CEA in cervical cancer. All three tumor markers showed some decline in positiveness after primary therapy. In ovarian cancer the decline of PHI and TPA strongly correlates with the achievable tumor resection. During the follow-up, all markers demonstrated some discriminatory power by comparing patients with recurrent disease versus recurrence free. Especially PHI and TPA in ovarian cancer, CEA in cervical cancer, and PHI in endometrial cancer seem to be the most suitable markers.

Acquired enzymatic activity defects of erythrocyte pyruvate kinase, glucose phosphate isomerase and phosphofructokinase have been studied in patients with acute myeloid leukemias, sideroblastic refractory anemias and unclassified acquired dyserythropoiesis. 6 patients with acute myeloid leukemia had a lowered erythrocyte pyruvate kinase activity; in 5 of them the concentration of the "pyruvate kinase"-antigen was parallely decreased, in such a manner that the ratio enzyme activity/immunologic reactivity (i.e. the molecular specific activity) was normal. In 1 patient with acute leukemia, 4 with refractory anemia and 1 with acquired dyserythropoiesis the defect of the pyruvate kinase activity was associated with a normal antigen concentration (and, therefore, the molecular specific activity in whole hemolysate was lowered). The enzyme activity was restored by incubation with SH reagents in two cases and by partial purification as often as it was performed. The electrofocusing pattern of erythrocyte pyruvate kinase was normal in both these types of defects. In two patients with so-called "acquired dyserythropoiesis" an erythrocyte glucose phosphate isomerase deficiency has been detected; in both the cases it was associated with a parallel decrease of the antigen concentration. The residual enzyme had a normal electrofocusing and electrophoretic pattern and a normal heat stability; the enzyme activity could not be restored by any treatment. In 1 patient with erythroleukemia and in 1 other with acquired dyserythropoiesis the erythrocyte phosphofructokinase activity was lowered. The enzyme activity was not restored by cross incubation in isologous plasma or by the SH reagents. In one case immunologic study could be performed, indicating that the enzyme defect was mainly due to the decreased ratio of the muscle type subunit of the erythrocyte phosphofructokinase. The electrofocusing pattern of deficient phosphofructokinases was normal. Finally, we point out the probable existence of several direct mechanisms, genetic and post translational, accounting for the acquired enzyme defects of red blood cells in various blood disorders.

We determined the enzyme activities of glucose-6-phosphate isomerase, alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase in serum from 23 normal controls, 27 anti-HIV seropositive individuals confirmed by Western blot, and 53 patients with acquired immunodeficiency syndrome (AIDS). There is a significant difference for all four enzyme activities among controls, HIV seropositive individuals, and patients with AIDS, the enzyme activities showing a progressive increase as the disease progresses. Evidently these enzyme measurements may be adjunctive biochemical markers for progression of AIDS.