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At least 181 records · Page 10Linked to original sources
PubMed1977

Radioimmunoassay of creatine kinase-B isoenzyme in human sera: results in patients with acute myocardial infarction.

A radioimmunoassay was developed to measure serum levels of the B isoenzyme of creatine kinase(ATP: creatine N-phosphotransferase, EC 2.7.3.2) (CPK) in order to evaluate the time course and frequency of MB isoenzyme elevation in patients with acute myocardial infarction. The method can identify as little as 0.2 ng of the B portion of the CPK-MB isoenzyme, does not significantly crossreact with CPK-MM isoenzyme, and is not affected by storage of serum at --20 degrees CPK isoenzyme containing B subunits was detected in 48 out of 51 sera from normal adults; serum levels in these individuals ranged between 1.2 and 12.5 ng/ml [mean +/- SEM was 2.7 +/- 0.30 ng/ml]. The mean serum level of CPK-B isoenzyme in a pool of sera obtained from 100 normal subjects was 2.9 +/- 0.35 ng/ml; two patients with rhabdomyolysis that were studied had serum CPK-B isoenzyme levels of 2.5 and 3.5 ng/ml, respectively. In contrast, serum levels of the CPK-B isoenzyme were markedly elevated in sera from 18 patients with acute myocardial infarcts when obtained within 12 hr after hospital admission; the mean +/- SEM concentration was 56 +/- 7.8 ng/ml. We performed serial determinations on 14 patients with acute myocardial infarcts and demonstrated that maximal serum CPK-B levels occurred within the first 12 hr after admission and were lower thereafter. The serum concentration of B-containing CPK isoenzyme in 19 additional patients admitted with chest pain but without acute myocardial infarction was 3.4 +/- 0.50 ng/ml. Thus, radioimmunoassay measurement of CPK-B isoenzyme appears to be a useful and sensitive test for the detection of acute myocardial infarcts in patients.

Acute Disease↗
PubMed1991

Cell cycle related studies on thymidine kinase and its isoenzymes in Ehrlich ascites tumours.

Thymidine kinase (TK) activity was measured in relation to the cell cycle of in vivo growing ascites tumour cells. The cells were synchronized by means of centrifugal elutriation and the cell cycle composition of the cell fractions was determined by flow cytometry. TK activity was low in G1, increased during S phase and declined in G2. A half-life of TK activity of about 45 min was found throughout the cell cycle. Four isoenzymes at pI values of 4.1, 5.3, 6.9 and 8.3, denoted as isoenzymes 1-4, were identified using isoelectric focusing. Isoenzymes 3 and 4 were responsible for the profound cell cycle related changes in the TK activity. Corresponding isoenzymes were also found in the fetal mouse liver. In the adult mouse liver isoenzyme 2 was the dominating isoenzyme. The half-life of the isoenzymes was in the same range as for the total TK activity. We conclude that the low TK activity in G1 is due to degradation of the enzyme in G2 at a normal rate combined with an arrest in the synthesis of TK. We also conclude that isoenzyme 4 and the intermediate isoenzyme 3, which had earlier been suggested to be a mitochondrial form of TK, in fact represent cytoplasmatic forms of TK. According to cell cycle and pI studies, isoenzyme 2 belongs to the mitochondrial form. Studies with various phosphor donors and specific substrates, however, indicate that it also contains a cytoplasmic component.

Animals↗
PubMed1982

Observations on the isoenzymes of creatine kinase in equine serum and tissues.

The isoenzymes of creatine kinase have been measured in serum and selected tissues from horses. The distribution followed that reported in other species in that the MM dimer of the isoenzyme was present in voluntary and non-voluntary muscle, thyroid, liver, spleen, lung and intestine. The BB dimer of the isoenzyme was predominant in brain, pancreas, kidney, intestine, lung, spleen, liver and thyroid. In contrast, in 4 hearts examined less than 1.5 per cent of the total creatine kinase activity was attributable to the MB form of the isoenzyme. The MB isoenzyme was, however, present in intestine and spleen. In this series the isoenzymes were separated by ion exchange chromatography and their presence confirmed by cellulose acetate electrophoresis. It was concluded that as insignificant quantities of MB isoenzyme are present in equine heart, measurement of this isoenzyme in serum cannot be used to detect myocardial or cardiac damage in the horse. Further detailed studies need to be undertaken to assess the clinical relevance of the isoenzyme pattern in serum or other body fluids, if the measurement of creatine kinase isoenzymes in serum is to be used as a diagnostic aid.

Animals↗
PubMed1974

Separation of three isoenzymes of N-acetyl-beta-D-hexosaminidase from human tissues by cellulose acetate membrane electrophoresis.

The separation of N-acetyl-beta-D-hexosaminidase isoenzymes from human tissues is used in the diagnosis and differential diagnosis of GM(2) gangliosidosis, since in type 1 the A isoenzyme is deficient and in type 2 both the A and B isoenzymes are deficient. Peripheral blood leucocytes are commonly used for these investigations, and the present study demonstrates that, in addition to these two isoenzymes, a third isoenzyme can be separated from leucocytes by cellulose acetate membrane electrophoresis. This isoenzyme is more anodic than the A and B isoenzymes and is similar to the hexosaminidase C isoenzyme recently reported in embryonic tissue extracts. The isoenzyme was also clearly demonstrable in human liver and kidney but was present in much lower concentrations in cultured cells. It could be demonstrated in leucocytes even after prolonged storage at -20 degrees , and, like the A isoenzyme, is partially inactivated by a short exposure to heat.

Cells, Cultured↗
PubMed1975

Simultaneous separation of serum creatine kinase and lactate dehydrogenase isoenzymes by ion-exchange column chromatography.

Lactate dehydrogenase isoenzymes were partially separated by use of a previously described column technique for creatine kinase [Clin. Chem. 20, 36 (1974)]. Extracts of lactate dehydrogenase-rich tissues were used to evaluate column resolution. Samples layered on mini-columns containing DEAE-Sephadex were eluted with Tris-buffered sodium chloride (100 and 200 mmol/liter). Lactate dehydrogenase activity in column effluents was measured by the Wacker method, and their isoenzyme content was assessed by electrophoresis on polyacrylamide gel. Dehydrogenase isoenzymes 3, 4, and 5 were separated from isoenzymes 1 and 2, and the separation was tissue-specific and reproducible. The electrophoretic technique for isoenzymes 3, 4, and 5 gave values about 20% lower than did the column technique. Sera from 15 healthy laboratory technicians contained total lactate dehydrogenase, isoenzymes 1 and 2, and isoenzymes 3, 4, and 5 in the ranges 94 to 152, 34 to 64, and 38 to 75 U/liter, respectively. Activities of sera from 15 patients with acute myocardial infarction (total lactate dehydrogenase) ranged from 212 to 800 U/liter and lactate dehydrogenase isoenzymes 1 and 2 ranged from 138 to 628 U/liter. Lactate dehydrogenase and creatine kinase isoenzymes were rapidly and easily measured after being simultaneously separated. The procedure is specific and sensitive for following the post-infarct time course of changes in isoenzyme activities.

Chromatography, DEAE-Cellulose↗
PubMed1976

Quantitative fractionation of alkaline phosphatase isoenzymes according to their thermostability.

Continuous monitoring of heat denaturation of a mixture of alkaline phosphatase isoenzymes at 60 degrees C and pH 7.5 permits the simultaneous direct identification and quantitation of three isoenzymes: the placental isoenzyme, the L-phenylalanine-sensitive intestinal isoenzyme, and the liver isoenzyme (hepatocytic). The isoenzyme that is principally of bone origin cannot be identified as such without the help of other diagnostic aids and the patient's medical history. All human tissues contain alkaline phosphatase, many organs more than one of the isoenzymes. Liver alkaline phosphatase, which constitutes 40-50% of normal serum alkaline phosphatase activity, was measured in the serum of persons with various liver diseases. Its activity exceeded normal in all types of liver disease; in 80% of cases this increase was accompanied by increased gamma-glutamyl-transferase activity, but the quantitative correlationship (r = 0.54) was not as good as expected if both enzymes come from the same source and are indices of liver dieases. Liver alkaline phosphatase activity increases in the blood early in liver disease, before most liver tests show abnormalities. The other major isoenzyme of normal serum probably represents a mixture of isoenzymes from bone and reticulo-endothelial and vascular tissues, which all contain the same "very heat-labile" alkaline phosphatase. Cord blood and children's sera contain mostly this very heat-labile isoenzyme.

Alkaline Phosphatase↗
PubMed1989

Lactate dehydrogenase isoenzyme pattern in sera of patients with malignant diseases.

Total lactate dehydrogenase (LDH; EC 1.1.1.27) activity and the percentage distribution of LDH isoenzymes were determined in 127 patients with malignant diseases. A shift in the isoenzyme patterns was observed toward the M-type, with an increase in the percentage of LDH-4 and LDH-5 isoenzymes and a slight increase in total LDH activity of all patients. Serum samples from 68 of the patients contained an abnormal isoenzyme of LDH, "LDH-1 ex," that, on agarose gel electrophoresis at pH 8.6, migrated between albumin and LDH-1 isoenzyme. Chemotherapy, radiotherapy, or surgical removal of the tumor was accompanied by disappearance of this abnormal isoenzyme. The heat stability of LDH-1 ex isoenzyme appears to be similar to that of LDH-1 but greater than that of the other LDH isoenzymes. Statistical analysis of these data demonstrated a significant correlation between malignancy and the appearance of LDH-1 ex isoenzyme (P less than 0.001). In contrast, the relationship between LDH-1 ex isoenzyme and metastasis or anatomical location of the malignancy is not statistically important (P less than 0.1).

Adult↗
PubMed1986

Changes in isoenzyme profiles during induction of differentiation in human myelomonocytic leukemia cell lines.

The human leukemia cell lines HL-60, KG-1, KLM-2, ML-3, THP-1, and U-937 were treated with the phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA). TPA partially or completely inhibited the proliferative activity of the cell cultures. The number of cells with the ability to reduce nitroblue tetrazolium increased in the TPA-treated cell lines HL-60, ML-3, THP-1, and U-937, whereas the cell lines KG-1 and KLM-2 remained nitroblue tetrazolium negative. Except for KG-1 and KLM-2, all TPA-treated cell lines showed varying degrees of strong adherence to plastic surface. The carboxylic esterase, acid phosphatase, hexosaminidase, and lactate dehydrogenase isoenzyme profiles from these cell lines were analyzed by isoelectric focusing on horizontal polyacrylamide gels. The new or stronger expression of an esterase isoenzyme which is specific for monocytes-macrophages was induced in HL-60, ML-3, THP-1, and U-937 but not in KG-1 or KLM-2. The new expression of the tartrate-resistant acid phosphatase isoenzyme was induced in ML-3, THP-1, and U-937. The number of esterase and acid phosphatase isoenzymes and the staining intensity of isoenzymes characteristic for myeloid cells were increased by TPA in all cell lines. The loss of the hexosaminidase I isoenzyme which is a marker of immature hematopoietic cells was noted in KG-1, ML-3, THP-1, and U-937. TPA triggered an increase in number and staining intensity of the lactate dehydrogenase isoenzymes in all cell lines. Some isoenzymatic changes (e.g., monocyte-specific esterase, tartrate-resistant acid phosphatase, hexosaminidase I) appear to correlate with TPA-induced differentiation while other alterations in the isoenzyme patterns do not (e.g., lactate dehydrogenase, other esterase and acid phosphatase isoenzymes). Differentiation of nonmonocytoid cells appears, at the isoenzyme level, to be quite different from that of the monocytoid cell lines.

Acid Phosphatase↗
PubMed1979

Expression of KB cell alkaline phosphatase isoenzymes during growth in immunosuppressed LEW rats.

Alkaline phosphatase isoenzyme expression of human tumor xenografts was studied by the growing of KB cells in immunosuppressed neonatal LEW rats. In culture these cells produced the oncoamniotic (FL) isoenzyme as the major form and the Regan isoenzyme as a minor fraction as well as a "hybrid" that shared properties of both of the other isoenzymes. Despite a reduction in specific activity, this isoenzyme pattern was essentially unchanged during in vivo growth. KB cells "pretreated" in culture with the glucocorticoid prednisolone in hyperosmolal medium exhibited a decrease in the levels of the oncoamniotic (FL) isoenzyme and an increase in the Regan isoenzyme. During growth of pretreated cells in vivo, a time-dependent resumption in the expression of the oncoamniotic (FL) isoenzyme was associated with the disappearance of the Regan isoenzyme. This shows that the expression of the oncoamniotic (FL) isoenzyme is not restricted to human tumor cells monophenotypic with respect to alkaline phosphatase.

Alkaline Phosphatase↗
PubMed1980

Convergence of isoenzyme expression in human tumor xenografts.

We have grown 7 bona fide non-HeLa contaminated cell lines in the cheek pouch of immunosuppressed adult hamsters. Six of the cell lines studied produced or continued to express the chorionic form of alkaline phosphatase under these conditions. The Regan isoenzyme produced in culture by the J82, T24, HCT-8, and COLO 16 cell lines disappeared in vivo with a concomitant appearance of the chorionic isoenzyme. The other cell lines, however, maintained the expression of the Regan isoenzyme when grown as a xenograft: the C41 line produced the Regan isoenzyme in culture, and continued to do so in vivo, while the BeWo cells, which synthesized the chorionic enzyme in culture were induced by in vivo growth to produce both the Regan and chorionic isoenzymes. No expression of the oncoamniotic (FL) isoenzyme was observed in any of the lines studied. Our results indicate a convergence of human tumor xenografts with respect to the production of the chorionic form of alkaline phosphatase. Furthermore, the loss of production of the Regan isoenzyme was seen in most, but not all cell lines studied. Since the oncoamniotic (FL) isoenzyme was only observed by HeLa cells growing as a xenograft, the expression of this enzyme form may be a HeLa specific phenomenon. We must now look to the regulation of the chorionic isoenzyme as the most promising avenue of approach to understanding the biological significance of altered isoenzyme expression in human tumor xenografts.

Alkaline Phosphatase↗
PubMed1982

Selective hormonal activation of cyclic AMP-dependent protein kinase isoenzymes in normal and malignant osteoblasts.

The pattern of cyclic AMP-dependent protein kinase isoenzyme response to acute hormonal activation has been studied in cultured cells derived from rat osteogenic sarcoma and osteoblast-rich cells grown from newborn rat calvaria. Using multiple small anion exchange columns and a batch elution technique, a rapid method of separating the isoenzymes of cyclic AMP-dependent protein kinase was developed and the acute activation by parathyroid hormone and prostaglandin E2 of each isoenzyme was studied. Activation was rapid, being detectable at 5 s, maximal at 15-30 s, and persisting for up to 6 h. Both hormones showed a dose-dependent activation of each isoenzyme in both cell types, but the patterns of response differed. Parathyroid hormone predominantly stimulated isoenzyme I in the clonal osteogenic sarcoma cells but showed equivalent activation of each isoenzyme in calvarial cells. Prostaglandin E2 also predominantly stimulated isoenzyme I in the malignant cells, whereas in the calvarial strain there was a major effect on isoenzyme II with almost no stimulation of isoenzyme I. Half-maximal stimulation of cyclic AMP-dependent protein kinase in the malignant cell strain was achieved for both hormones at concentrations an order of magnitude lower than those in the normal strain. These studies demonstrate selective activation of cyclic AMP-dependent protein kinase isoenzymes by hormones. Furthermore, the nature of the response differs between the normal and the corresponding neoplastic cell types for the same hormone stimulus.

Animals↗
PubMed1981

[6-phosphogluconate dehydrogenase of Aspergillus oryzae (Ahlburg). II. Separation and study of isoenzymes].

Through ammonium sulphate fractionation followed by ion-exchange chromatography, two forms of 6-phosphogluconate dehydrogenase (6j-phosphogluconate: NADP+ oxidoreductase E.C. 1.1.1.44) were isolated from mycelium of Aspergillus oryzae. The Km values for 6PG were the same, but the Km for NADP+ was smaller for isoenzyme I. The Vmx values were also different, with greater activity for isoenzyme II. The optimum pH for isoenzyme I was 7.5. whereas the isoenzyme II had two maximum peaks, at pH 7.5 and 9. Isoenzyme II was the more resistant to thermal inactivation. Inhibition by NADPH was competitive with respect to NADP+, with a Ki value similar for both isoenzymes. The GSSG inhibits isoenzyme I and activates isoenzyme II. The apparent molecular weights determined by gel filtration were 79,000 +/- 2,000 daltons for isoenzyme I and 112,000 +/- 2,000 daltons for isoenzyme II.

Aspergillus↗
PubMed1994

[Lactate dehydrogenase isoenzymes in mammalian and chicken serum].

In the article we describe characteristics of lactate dehydrogenase (LD) (EC 1.1.1.27) isoenzymes of fowl origin. We compare them with characteristics of evolutionary different mammalian forms of the enzyme. Separations of LD isoenzymes have been done using the most progressive electrophoretic techniques available at present. They included electrophoresis in homogeneous and gradient polyacrylamide gels (PAGE) as well as isoelectric focusing (IEF). A typical densitometric pattern of serum LD isoenzymes obtained by gradient PAGE is illustrated in Fig. 1. It is obvious that LD isoenzymes of all investigated animals have been well separated under applied experimental conditions, with an exception of fowl serum. We succeeded in separating fowl LD isoenzymes using isoelectric focusing. It was possible to distinguish five fractions of lactate dehydrogenase (Fig. 2) by this technique. As shown in Fig. 2, mobility of avian isoenzymes in the gradient of pH differs from that of their mammalian analogues. Fowl LD isoenzymes were localized in cathodic part of IEF-gram. In the case of mammalian isoenzymes (cattle and rabbit), we found LD4 and LD5 forms of the enzyme in this part. The major fractions, i.e. LD1 to LD3 were present in anodic part of IEF-gram. We quantitatively expressed this different mobility of mammalian and avian forms of LD using retention factors Rf (Tab. III). A migration distance of cattle LD1 served as a reference point. It could be seen from a comparison of Rf values that avian forms of LD (of galiform origin) differed from mammalian ones by an outstanding shift of their isoelectric points, especially that of LD1, toward basic values. The total LD activity (IU) and the relative distribution of the LD isoenzyme activities (%) in normal serum of various animals are listed in Tabs I and II. A comparison of these values showed that, in contrast to mammalian serum (with the exception of the rat one), LD5 was the predominant fraction in fowl serum, followed by LD4. LD1 to LD3 occurred in low amounts with fairly similar proportions. On the other hand, most of mammalian serum revealed a reverse pattern of LD isoenzymes, i.e. predominant portion of serum activity had been concentrated in the first three anodic fractions and LD4 and LD5 had been found to be minor ones.

Animals↗
PubMed1977

Separation of tissue and serum acid phosphatase isoenzymes by ion-exchange column chromatography.

I describe a simple, rapid ion-exchange column-chromatographic technique for separating the acid phosphatase (EC 3.1.3.2) isoenzymes in human serum and tissue. Extracts of platelets, spleen, liver, erythrocytes, and prostate were used to determine optimum conditions for separating these isoenzymes. Samples layered on mini-colunms of DEAE-Sephadex A-50 were eluted stepwise with sodium chloride (100, 200, and 300 mmol/liter, buffered with tris (hydroxymethyl)aminomethane). Activity in column effluents was measured with p-nitrophenol phosphate as substrate, and their isoenzyme content was assessed by electrophoresis on polyacrylamide gel. Comparision of activity patterns so derived for various tissues revealed prostatic tissue to be a rich source of acid phosphatase isoenzyme 2 activity. Evaluation of sera from six patients with prostatic cancer revealed isoenzyme patterns with prominent amount of isoenzyme 2 (3.8 to 27.6 U/liter). sera from 10 healthy laboratory technicians contained isoenzyme 2 in the range of 0.3-0.5 U/liter. Samples from two patients with abnormally high activity owing to nonprostatic conditions (Gaucher's disease and carcinoma of lung) exhibited less than 2 U of isoenzyme 2 per liter and acid phosphatase isoenzymes 3-5 that were 50- to 100-fold the normal range. Quantification of isoenzyme 2 by DEAE-Sephadex column chromatography as described appears to provide a more sensitive and specific approach to diagnosis of prostatic cancer.

Acid Phosphatase↗
PubMed1987

Purification and Partial Kinetic and Physical Characterization of Two Chloroplast-Localized NADP-Specific Glutamate Dehydrogenase Isoenzymes and Their Preferential Accumulation in Chlorella sorokiniana Cells Cultured at Low or High Ammonium Levels.

Two ammonium-inducible, chloroplast-localized NADP-specific glutamate dehydrogenase isoenzymes were purified to homogeneity from Chlorella sorokiniana. These isoenzymes were homopolymers of either alpha- or beta-subunits with molecular weights of 55,500 or 53,000, respectively. The alpha-isoenzyme was preferentially induced at low ammonium concentrations (2 millimolar or lower), whereas only the beta-isoenzyme accumulated after cells were fully induced (120 minutes) at high ammonium concentrations (29 millimolar). Purification of isoenzymes was achieved by (NH(4))(2)SO(4) fractionation, gel-filtration, anion-exchange fast protein liquid chromatography, and affinity chromatography. The alpha- and beta-isoenzymes were separated by their differential binding to Type 4 nicotinamide adenine dinucleotide phosphate-Sepharose. Both isoenzymes bound to an antibody affinity column to which purified antibody (prepared against beta-isoenzyme) was covalently attached. Peptide mapping of the subunits showed them to have a high degree of sequence homology. Both subunits were synthesized in vitro from precursor protein(s) with a molecular weight of 58,500. Although the subunits have similar chemical, physical, and antigenic properties, their holoenzymes have strikingly different ammonium K(m) values. The ammonium K(m) of the beta-isoenzyme remained constant at approximately 75 millimolar, whereas this K(m) of the alpha-isoenzyme ranged from 0.02 to 3.5 millimolar, depending upon nicotinamide adenine dinucleotide phosphate concentration.

Journal Article↗
PubMed1991

Genetic deficiency of human class mu glutathione S-transferase isoenzymes in relation to the urinary excretion of the mercapturic acids of Z- and E-1,3-dichloropropene.

Mononuclear lymphocytes were isolated from the blood of 12 individuals, who had been exposed to the vapour of the soil fumigant 1,3-dichloropropene (DCP). Western blot experiments were performed on the crude lymphocyte homogenates, using a monoclonal antibody against human hepatic glutathione S-transferase (GST) isoenzyme mu, to determine the presence or absence of mu-class isoenzymes mu and/or psi. Nine of the individuals were found to be positive for mu and/or psi, the remaining three individuals being negative. In addition, all individuals showed a positive staining on immunoblot of a protein of somewhat lower molecular mass than the hepatic standard. This protein was bound by the S-hexylglutathione affinity column, and presumably constitutes a new mu-class isoenzyme, which is not subject to genetic polymorphism. Determination of the specific activities of individual human GST isoenzymes towards Z-(cis-) and E-(trans-)-DCP demonstrated that mu-class isoenzymes show a considerably higher specific activity with Z-DCP than alpha-class or pi-class isoenzymes. In addition, mu-class isoenzymes were found to be 2- to 3-fold more active with Z-DCP than with E-DCP. Their activity towards E-DCP was similar to the specific activity of alpha-class isoenzymes. Genetic polymorphism for mu-class isoenzymes could thus be a determinant in the extent of excretion of mercapturic acids from Z- and E-DCP. The urinary excretion of Z- and E-DCP mercapturic acids and the respiratory exposure to Z- and E-DCP were determined for nine and eight phenotyped individuals, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcysteine↗
PubMed1998

Morphologic, biometric, and isoenzyme characterization of Trichuris suis.

Trichuris suis isolates were collected from the cecum of Sus scrofa domestica (pig) and S. s. scrofa (wild boar). Morphology and biometry studies were carried out. Morphology studies showed the existence of typical caudal papillae in males of T. suis from wild boars, but no other difference was observed in the biometric parameters (total length, esophageal length, posterior-portion body length, and spicular length) of T. suis isolated from either host. Individual extracts were subjected to malate dehydrogenase (MDH), malic enzyme (ME), glucose 6-phosphate dehydrogenase (G6PD), lactate dehydrogenase (LDH), and superoxide dismutase (SOD) isoenzyme analysis following starch-gel electrophoresis, and the isoenzyme patterns were compared with those obtained from other species of trichurids. MDH, ME, G6PD, LDH, and SOD isoenzyme patterns were identical for T. suis from both hosts. MDH isoenzyme patterns were characterized by the presence of one cathodic isoenzyme. ME, G6PD, and LDH isoenzyme patterns indicated the presence of three phenotypes, whereas the SOD isoenzyme pattern showed only one phenotype characterized by the existence of two (anodic and cathodic) bands. Different LDH and SOD isoenzyme patterns observed for T. suis, T. ovis, and T. skrjabini confirm once more that isoenzyme patterns have potential as a diagnostic tool for differentiation of different species of Trichuris.

Animals↗
PubMed1988

Usefulness of lactate dehydrogenase and lactate dehydrogenase isoenzymes for diagnosis of acute myocardial infarction.

The usefulness of lactate dehydrogenase (LD) and LD isoenzymes in the diagnosis of acute myocardial infarction (AMI) is controversial. The present study reviewed 507 consecutive patients in whom creatine kinase, creatine kinase isoenzymes, LD and LD isoenzymes were ordered over a 1-month period. Of these, 249 had an insufficient number of serial enzyme determinations to establish a laboratory diagnosis of AMI. After excluding an additional 11 patients for other reasons, 247 patients remained for analysis. Of these, only 2 (0.8%) had myocardial infarction by standard clinical criteria with normal creatine kinase and creatine kinase-MB but elevated LD and abnormal LD isoenzymes. Seven patients (7 of 247, 2.8%) had false-positive LD isoenzymes. Thus, the routine use of LD and LD isoenzymes was of no use in most patients (96%) and led to the incorrect diagnosis of AMI more than 3 times as often as it helped with a correct diagnosis. Total 1-month charges for all the LD and LD isoenzymes obtained equalled +42,450. Therefore, it appears that LD and LD isoenzymes are not routinely useful in the diagnosis of AMI and may result in considerable unnecessary expense. It is suggested that LD and LD isoenzymes be ordered only under suspicion of late presentation (greater than 48 hours) of AMI.

Creatine Kinase↗