Clinical significance of the human acid phosphatases: a review

During the past three decades we have witnessed significant developments in the clinical application and interpretation of both serum and tissue acid phosphatases. The human prostate is particularly rich in this enzyme, and serum enzyme levels are a useful tool in the diagnosis and management of prostatic diseases. Alterations of serum enzyme activity are not, however, unique to prostatic disorders and are seen in a wide variety of other diseases, particularly in Gaucher's disease and nonprostatic malignancies with bone involvement. It is now apparent that acid phosphatases represent a heterogeneous group of enzymes containing many isoenzymes, each specific for one type of tissue. Determination of the serum isoenzyme pattern is often a valuable aid in directing the physician's attention to one particular tissue; moreover, the isoenzyme pattern may show abnormalities in the face of normal total serum enzyme. The present trend in study of the acid phosphatases includes the combined use of biochemical, histochemical, electrophoretic, electron microscopic and immunologic technics to further our understanding of the relationship between these isoenzymes and the cellular and subcellular fractions of various tissues. Such studies will lead to a further understanding of the function of acid phosphatases and may serve to extend the clinical application of these enzymes.     

Extraglomerular immunoglobulin deposits in human nephritis.

In order to evaluate the incidence of extraglomerular immunoglobulin deposits and to correlate their presence with histopathologic abnormalities, we performed both prospective and retrospective immunofluorescence studies of renal biopsy specimens. Of 200 diagnostic biopsy specimens examined prospectively, 21 had extraglomerular deposits, 19 in association with presumed immunologically-mediated glomerulonephritis. Nine had linear immunoglobulin deposits on tubular basement membrane (antitubular basement membrane antibodies), in one case coexisting with granular deposits, and 13 had granular deposits on tubular basement membrane, in peritubular capillaries and/or arteries, or in tubular cytoplasm (probably immune complexes). Linear deposits on tubular basement membrane were usually associated with antiglomerular basement membrane nephritis or methicillin-associated interstitial nephritis; granular extraflomerular deposits were seen primarily in systemic lupus erythematosus, cryoglobulinemia or membranoproliferative glomerulonephritis.. The incidence of immunoglobulin deposits was high in the three groups of patients examined retrospectively being present in 37 or 47 patients with antiglomerular basement membrane mephritis, 22 or 32 patients with systemic lupus erythematosus of 24 of 130 renal allograft recipients. The contribution of antitubular basement membrane antibodies to renal damage was difficult to assess, although studies in experimental animals attest to their pathogenicity. The occurrence of granular extraglomerular deposits appeared to correlate roughly with the degree of tubulointerstitial injury in the patients with systemic lupus erythematosus.     

Clinical and immunologic features of transient cold agglutinin hemolytic anemia

Atypical pneumonitis, often induced by infection with Mycoplasma pneumoniae, is frequently associated with elevated cold agglutinin titers but only rarely with significant hemolytic anemia. An example and documentation of the clinical and immunologic course of such transient cold agglutinin hemolytic anemia is presented, and the immunochemical characteristics of cold agglutinins in this syndrome are assessed in regard to their biologic implications and diagnostic significance. Transient cold agglutinins, such as observed in this case, commonly appear to be of a restricted polyclonal character and as first demonstrated in this case may possess structural determinants usually considered unique for monoclonal cold agglutinins. Although the immunopathogenetic mechanisms and certain clinical manifestations of the various forms of cold agglutinin hemolytic anemia appear similar, the immunogenic basis of cold agglutinin production and the molecular structure of transient cold agglutinins are quite distinctive and provide reasonably reliable guidelines for the differential diagnosis of the cold agglutinin syndromes and for consideration of appropriate clinical management.     

Alpha 1-antitrypsin deficiency associated with PZ and MP phenotypes. Clinical and laboratory correlations

In a large kindred we have identified two siblings with the hitherto unreported PZ phenotype and eight other subjects with the MP phenotype. In subjects with the MP phenotype serum alpha₁-antitrypsin levels are near the lower limits of normal. In contrast, subjects with the PZ phenotype have severely depressed alpha₁-antitrypsin levels. One subject with the PZ phenotype at age 34 already shows evidence of obstructive lung disease. We found no convincing evidence of obstructive lung disease in family members with the MP phenotype. After purification of alpha₁-antitrypsin from the serum, isoelectric focusing and acrylamide gel electrophoresis can be used to distinguish normal protein from the products of the Pi^P and Pi^Z alleles. Subjects with the PZ phenotype have more Pi^P than Pi^Z product.     

Thrombocytopenia associated with gold therapy: Observations on the mechanism of platelet destruction

Severe thrombocytopenia developed in a patient with rheumatoid arthritis during gold therapy. Increased numbers of marrow megakaryocytes, shortened ⁵¹Cr-labeled platelet survival and platelet phagocytosis by splenic macrophages indicated that thrombocytopenia was due to excessive platelet destruction. Aurothiomalate disodium antigenicity was demonstrated by increased lymphocyte blastogenesis, and accentuation of blood and splenic leukocyte migration in the presence of the gold salt. In vitro splenic immunoglobulin G (IgG) production was markedly increased, and a significant portion of the culture-produced IgG attached specifically to homologous platelets and platelet membranes. Serum antiplatelet antibodies could not be demonstrated, nor could it be shown that gold enhanced the binding of splenicsynthesized IgG to platelets. The data indicate an immunologic mechanism for gold-associated thrombocytopenia and permit speculation as to possible ways in which unidentified antigens may be involved in the pathogenesis in idiopathic thrombocytopenic purpura.     

Activation of Hageman factor in the nephrotic syndrome

The patient described had the nephrotic syndrome associated with decreased levels of plasma coagulation factors XI (35 per cent) and XII (15 per cent). The patient also had a decrease in concentration of prekallikrein and kallikrein inhibitor, suggesting that the kallikrein system was activated. Addition of purified factor XII did not correct this defect. The fibrinolytic system was activated as indicated by an increase in fibrinogen split products. Thus, it seems that three Hageman-dependent proteolytic pathways (coagulation, fibrinolysis and kallikrein) were activated in this patient with the nephrotic syndrome.Another possible cause of decreased factors XI and XII is urinary loss of these proteins. The urine did contain apparent activities of factors XI and XII. The finding of factor VIII in the urine in higher concentrations than XI or XII, however, as well as the inability to adsorb the activity with Celite®, suggested that the activity was due to a nonspecific urinary procoagulant. This hypothesis was confirmed by removal of the activity via adsorbtion of the urine with barium citrate.     

Urinary excretion of Hageman factor (factor XII) and the presence of nonfunctional Hageman factor in the nephrotic syndrome

Acquired deficiencies of functional Hageman factor (factor XII) and prekallikrein, proteins involved in the plasma kinin-generating system, have been previously reported in the nephrotic syndrome. The basis for these changes, however, is not fully understood. We have examined the levels of Hageman factor and prekallikrein by functional and radioimmunoassays in plasmas and urines of 11 patients with the nephrotic syndrome. All 11 patients had decreased titers of plasma Hageman factor activity (mean ± standard deviation (SD), 0.29 ± 0.15 U/ml), but essentially normal titers of immunoreactive Hageman factor (0.88 ± 0.23 U/ml). The ratio of immunoreactive Hageman factor to functional Hageman factor (2.63 ± 0.86) was significantly higher than that in nine control patients (1.08 ± 0.17). Since no circulating anticoagulants against Hageman factor were detected, these data suggest the presence of nonfunctional (altered) Hageman factor in plasmas of patients with the nephrotic syndrome. Urinary excretion of Hageman factor was present in six patients but did not appear to account for the reduced plasma Hageman factor activity. Urinary Hageman factor in one patient had the same size as plasma Hageman factor as assessed by gel filtration and sucrose density gradient centrifugation. The titers of plasma prekallikrein were within the normal range. These studies indicate urinary excretion of Hageman factor and alterations in the functional sites of plasma Hageman factor molecules in the nephrotic syndrome. Whether these changes are related to the pathogenesis of the nephrotic syndrome remains to be determined.     

Gout with purine overproduction due to increased phosphoribosylpyrophosphate synthetase activity

Two brothers with marked purine overproduction and clinical gout showed activity of the enzyme phosphoribosylpyrophosphate (PP-ribose-P) synthetase in erythrocyte lysates 2.5 to 3.0-fold greater than that found in normal subjects or in other patients with gout. Associated with the increased activity of this enzyme, which catalyzes the synthesis of the regulatory substrate PP-ribose-P from adenosine triphosphate (ATP) and ribose-5-phosphate, was an increased intracellular PP-ribose-P concentration and an increased ability of intact erythrocytes to generate PP-ribose-P. In fibroblasts cultured from one of the affected brothers, these findings were confirmed, and an increased rate of the de novo purine biosynthetic pathway was demonstrated both in fibroblasts and in the affected brothers in vivo. The association of altered PP-ribose-P synthetase activity with increased intracellular PP-ribose-P generation and increased purine synthesis suggested that the proximal cause of the patients' gout was the increased enzyme activity.Hemolysates from a daughter of one of the affected brothers contained increased enzyme activity suggesting dominant hereditary transmission of the abnormality.The increased enzyme activity appeared to reside in the enzyme protein, although no evidence for a structural alteration in the patients' enzyme has thus far been found. Increased PP-ribose-P synthetase activity was apparent over a wide range of inorganic phosphate concentrations distinguishing the present abnormality from one previously described.Increased PP-ribose-P synthetase activity represents another hereditary enzyme aberration resulting in purine overproduction and clinical gout and demonstrates that human disease states can result from overabundance of enzyme activity as well as from deficiency.     

Competitive ligand-binding radioassays for serum proteins

This review is concerned with those competitive radioimmunoassays that are utilized for determination of the concentration of human serum proteins. Radioimmunoassays that measure the levels of the immunoglbulins, complement component C3, plasminogen, fibrinogen, hemopexin, haptoglobin, thyroxine-binding globulin, retinol-binding protein, albumin, and histocompatibility antigens are discussed. In these radioimmunoassays, which employ indirect or competitive binding, the amount of unlabeled antigen is directly proportional to the degree of inhibition it exerts on the reaction between antibody and isotope-labeled antigen. To perform the radioassay, one needs an extensively purified antigen, high affinity antibodies, and an effective means of separating the free from the bound antigen. The assays have proven to be sensitive, efficient, and economical. They are invaluable in detecting minute quantities of proteins in serum and other body fluids and are useful in evaluating structural similarities between proteins.     

Gram-negative bacillary endocarditis. Interpretation of the serum bactericial test.

Although the serum bactericidal test is commonly used in the management of infective endocarditis, little has been written about its validity or limitations. We report three cases of gram-negative bacillary endocarditis (Pseudomonas aeruginosa, Vibrio fetus and Serratia marcescens) encountered in 1 year at a Veterans Administration hospital. Serum bactericidal titers were considered necessary to identify inadequate antibiotic regimens or to avoid unnecessary drug toxicity. The limitations of the test, particularly those pertaining to gram-negative infections, are reviewed. Misleading results during treatment with aminoglycoside antibiotics could be due to the tendency of serum to become alkaline on standing. A detailed study of the interaction of the complement-dependent bactericidal system of serum with eight antibiotics is presented. In the context of the serum bactericidal test, the interaction was additive or synergistic in 15 of 16 determinations, indicating the need to include a control study of serum sensitivity of the infecting microorganism in each case.     

Guillain-Barré syndrome following administration of live measles vaccine.

In a 19 month old girl and a 10 month old girl the Guillain-Barre syndrome developed within a week after they received, respectively, live measles-rubella vaccine and live measles vaccine. The older child was immune to the rubella at the time of vaccination, but both girls demonstrated a primary measles antibody response. Serum obtained during the acute and convalescent stages from the younger child was tested for antibodies against the herpes viruses (herpes simplex, Epstein-Barr virus, cytomegalovirus and varicella-zoster) and found to be negative.     

Rickets and the pathogenesis of impaired tubular transport of phosphate and other solutes

This discussion concerns the nature of the renal tubular disorders in acquired vitamin D deficiency and in two forms of so-called vitamin D-resistant hereditary rickets (autosomal recessive vitamin D dependency and X-linked hypophosphatemia). The first of the three conditions yields information of use in interpreting the second, and the first two yield information relevant to the third disease; all three are instructive about tubular transport mechanisms in general. Resistance to vitamin D in the autosomal recessive disease probably reflects an inborn error of vitamin D biosynthesis, whereas the primary abnormality in the X-linked condition appears to be an impairment of transepithelial transport of phosphate.     

Myeloblastic leukemic cells causing suppression of granulopoiesis and excessive binding of colony-stimulating activity. The effect of antithymocyte globulin.

The three and a half year course of an adult woman (65 years) with myeloblastic leukemia, the leukemic clone being trisomic for chromosome #8, was characterized by suppressed granulopoiesis despite a small mass of leukemic tissue relative to cytogenetically normal marrow precursors. The leukemic tissue was shown to be productive of mature neutrophilic granulocytes with hypersegmented nuclei and increased alkaline phosphatase content. These granulocytes showed active phagocytosis but diminished fungicidal capacity. The leukemic tissue inhibited granulocyte-monocyte colony formation in soft agar with colony-stimulating activity from human and murine sources when co-cultured with normal, chronic myelocytic leukemia, Philadelphia chromosome positive (CML Ph¹⁽⁺⁾) human and C57 black (BL) murine marrow. This inhibition was associated with binding of colony-stimulating activity at sites on the leukemic cells which failed to elicit colony formation by leukemia colony-forming units, culture (CFUc). Pretreatment of the leukemic tissue with antithymocyte globulin (ATG) before co-culture removed the inhibitory effect of the leukemic tissue and promoted colony formation by leukemic CFUc. This effect of ATG involved competitive binding of colony-stimulating activity and ATG by leukemic cells since the consumption of colony-stimulating activity by leukemic cells was blocked by prior treatment of leukemic cells with ATG. Infusion of autochthonous cytogenetically normal marrow after two years of cryopreservation was ineffective in altering the neutropenic state. Bacteremia (Klebsiella pneumoniae) at a time when the marrow contained mostly leukemic precursors was associated with transient neutrophilic granulocytosis involving mature leukemic progeny. ATG given to the patient in a preterminal state was associated with a simitar leukocytosis as well as colony formation in vitro by the leukemic marrow tissue.     

The biochemistry of the renin-angiotensin system and its role in hypertension.

The renin-angiotensin system has an important role in maintaining elevated blood pressure levels in certain forms of experimental and human hypertension. Renin, an enzyme produced by the juxtaglomerular cells of the kidney, acts on a protein substrate found in the alpha 2-globulin fraction of the plasma to produce a decapeptide, angiotensin I. This decapeptide is not directly pressor, but on passage through the pulmonary circulation is converted to an octapeptide, angiotensin II, a very potent pressor substance which acts by causing constriction of arteriolar smooth muscle. In addition to its direct action which increases blood pressure, angiotensin II acts on the adrenal cortex to cause the release of the sodium-retaining hormone aldosterone. Recent evidence suggests that this action may be mediated by the heptapeptide, angiotensin III. Both renin and its protein substrate exist in multiple forms and renin may also exist as a high molecular-weight "pro-hormone," although the physiologic significance of these forms is not clear. The elucidation of the biochemistry of the renin-angiotensin system has provided us with inhibitors which allow the system to be blocked effectively in vivo. Thus, angiotensin antagonists such as Sar 1, IIe 8-angiotensin II and converting enzyme inhibitors such as BPP 9a (SQ 20881) have proved useful in the study of experimental and human hypertension.     

Relative ventilation and perfusion of left versus right lung in mitral stenosis

We measured relative ventilation, perfusion and ventilation/perfusion ratio of the left versus the right lung using a radioactive xenon method in 15 seated patients with mitral stenosis. The relative ventilation/perfusion ratio of the left lung was significantly less in these patients than in 11 normal subjects and there was a significant negative correlation between the ventilation/perfusion ratio of the left lung and pulmonary intravascular pressure. There was little difference between relative perfusion of the two lungs, and the reduced ventilation/perfusion ratio of the left lung seems to be mainly due to relative hypoventilation, perhaps the result of compression or distortion of the left main stem bronchus. None of the patients had more than a slight reduction in the ventilation/perfusion ratio of the left lung, and it is not likely that between lungs differences in regional function significantly affect the efficiency of gas exchange.We found no significant correlation between the relative ventilation/ perfusion ratio of the left lung and pulmonary intravascular pressure in 10 patients with mitral stenosis studied in the supine position.     

Phosphorylase kinase mediating the effects of cyclic AMP in muscle.

In the classic view of the control of phosphorylase b to a conversion by catecholamines, cyclic AMP acts as the second messenger stimulating the activity of cyclic AMP-dependent protein kinase to covalently modify phosphorylase kinase. Phosphorylation of phosphorylase kinase converts this enzyme form with a nonactivated to an activated form with a markedly higher activity at pH 7. There is now considerable evidence that the activity of phospphorylase kinase is also regulated by changeds in the Ca-2+ concentration. The activity of both nonactivated and activated phosphorylase kinase is stimulated by Ca-2+ in the range of concentrations that have been reported to occur in the sacroplasm of contracting muscle, with the activated pphosphorylase kinase having a lower K-alpha for Ca-2+. Thus there are at leaset two mechanisms for the regulation of phosphorylase kinase activity in muscle. These mechanisms may act independently or in concert in controlling glycogenolysis stimulated by catecholamines, anoxia, or tetanic electrical stimulation...     

Restoration of effective hemopoiesis preceding suppression of leukemic clone in myeloblastic leukemia

A 63 year old Caucasian woman presented with myeloblastic leukemia and a hyperdiploid C group chromosome change in 10 per cent of marrow metaphases. Treatment with cytotoxic agents resulted in an increased percentage (52 per cent) of these hyperdiploid marrow cells. Furthermore, the marrow continued to show leukemic features morphologically and in culture. Despite the indications of persistence or progression of the hyperdiploid, putatively leukemic line at cessation of chemotherapy and for a period of time thereafter, remission was achieved and blood and marrow cell numbers one year after cessation of all treatment are normal. The hyperdiploid line is no longer detectable. This case raises questions concerning the mechanism whereby remission is attained in some cases of acute leukemia and is discussed in terms of the restoration of normal hemopoiesis eliminating the leukemic process.