Hyperhomocysteinemia due to pernicious anemia leading to pulmonary thromboembolism in a heterozygous mutation carrier.

Pulmonary thromboembolism is a life-threatening condition resulting mostly from lower extremity deep-vein or pelvic-vein thrombosis. A 46-year-old woman was admitted to hospital with pain on the right side of the chest and hemoptysis. On laboratory analysis, D-dimer level was elevated. Computed tomographic pulmonary angiography revealed intravascular filling defects due to thrombi in right lower lobe pulmonary segmental arteries. Screening for thrombophilic states was normal except for heterozygous mutations of both prothrombin and methylene tetrahydrofolate reductase (MTHFR 677) genes. Homocysteine level was high, and vitamin B12 level and serum ferritin level were reduced. Serum antiparietal antibody was positive, and therefore, pernicious anemia was diagnosed along with iron-deficiency anemia. After the diagnoses were established, enoxaparin followed by warfarin was started in addition to oral vitamin B12, pyridoxine, thiamine, folic acid, and ferroglycine sulfate supplementation. At the end of 8 weeks of the replacement therapy, vitamin B12, folate, and homocysteine levels and red cell volume were found to be normal, with complete resolution of the thrombus confirmed by repeat computed tomographic pulmonary angiography. We conclude that hyperhomocysteinemia due to vitamin B12 deficiency associated with pernicious anemia might have decreased the threshold for thrombosis. In addition, the presence of heterozygous prothrombin and methylene tetrahydrofolate reductase mutations might serve as synergistic cofactors triggering pulmonary thromboembolism.

Anemia with LDH-elevation in a patient with aortic valve replacement.

In a 63-year old patient with a history of aortic valve replacement in 1986, a reduced hemoglobin of 91 g/l was found by a family physician. Since serum LDH was also increased, the patient was diagnosed to suffer from mechanically induced, hemolytic anemia and presented at our hospital for further diagnosis and evaluation of the aortic valve prosthesis.

Monoclonal antibodies specific for the core protein of the beta-subunit of the gastric proton pump (H+/K+ ATPase). An autoantigen targetted in pernicious anaemia.

The gastric H+/K(+)-transporting adenosine triphosphatase (H+/K+ ATPase) (proton pump) consists of a catalytic alpha-subunit and a recently proposed 60-90-kDa glycoprotein beta-subunit. Using dog gastric membranes as the antigen, we have produced two murine monoclonal antibodies, 4F11 (IgG1) and 3A6 (IgA), which are specific for the 60-90-kDa glycoprotein. The monoclonal antibodies (1) specifically stained the cytoplasm of unfixed and formalin-fixed dog gastric parietal cells; (2) specifically reacted by ELISA with gastric tubulovesicular membranes; (3) recognised epitopes located on the luminal face of parietal cell tubulovesicular membranes, the site of the proton pump, by immunogold electron microscopy; (4) immunoblotted a 60-90-kDa molecule from tubulovesicular membranes and a 35-kDa component from peptide N-glycosidase-F-treated membrane extracts; (5) immunoblotted the 60-90-kDa parietal cell autoantigen associated with autoimmune gastritis and pernicious anemia, purified by chromatography on parietal cell autoantibody- or tomato-lectin-Sepharose 4B affinity columns, and the 35-kDa protein core of this autoantigen; this autoantigen has amino acid sequence similarity to the beta-subunit of the related Na+/K(+)-transporting adenosine triphosphatase (Na+/K+ ATPase) [Toh et al. (1990) Proc. Natl Acad. Sci. 87, 6418-6422]; (6) co-precipitated a molecule of 95 kDa with the 60-90-kDa molecule from 125I-labelled detergent extracts of dog tubulovesicular membranes; and (7) co-purified the catalytic alpha-subunit of the H+/K+ ATPase with the 60-90-kDa molecule by immunoaffinity chromatography of tubulovesicular membrane extracts on a monoclonal antibody 3A6-Sepharose 4B column, indicating a physical association between the two molecules. These results provide further evidence that the 60-90-kDa glycoprotein is the beta-subunit of the gastric H+/K+ ATPase. We conclude that the monoclonal antibodies specifically recognise luminal epitopes on the 35-kDa core protein of the 60-90-kDa beta-subunit of the gastric proton pump, a major target molecule in autoimmune gastritis and pernicious anaemia. These monoclonal antibodies will be valuable probes to study the structure and function of this associated beta-subunit, as well as the ontogeny of the gastric proton pump.

Vitamin B12-induced reduction of platelet monoamine oxidase activity in patients with dementia and pernicious anaemia.

Platelet monoamine oxidase (MAO) activity has previously been shown to be increased in patients with senile dementia of Alzheimer type (SDAT) and in patients with megaloblastic anaemia. Moreover, low serum B12 levels were found to be 4-5 times more frequent in SDAT compared with an unselected population of similar age. In the present investigation, platelet MAO activity was estimated in 14 SDAT patients with relatively low serum B12 levels and in 4 patients with pernicious anaemia. Before B12 therapy, platelet MAO activity was significantly increased in both patient groups compared with a control group. After B12 therapy, platelet MAO activity was significantly reduced in both patient groups to apparently normal levels. The present results show that B12 status is a controlling factor of platelet MAO activity and confirm that a significant connection exists between vitamin B12 deficiency and primary degenerative dementia disorders, such as SDAT.

Platelet peroxidase-like activity detected in mature erythroblasts from a patient with pernicious anemia.

We report a case of pernicious anemia in which the possession of platelet peroxidase (PPO)-like activity was proved in its erythroblasts. PPO-positive cells were found in a distinct minor population of hemoglobinized (as a mean of differentiated) erythroid cells in the bone marrow before treatment, but these cells disappeared following therapy with vitamin B12. The present report is considered to be the first case to identify PPO-like activity in mature erythroblasts from the nonmalignant clone. The existence of PPO in erythroid lineage in cases with pernicious anemia is discussed.

Erythrocyte superoxide dismutase activity in patients with pernicious anemia and chronic lymphocytic leukemia.

Superoxide dismutase activity was determined in the erythrocytes of healthy individuals and patients suffering from pernicious anemia, chronic lymphocytic leukemia and dyserythropoetic anemia type II. Enzyme activity was significantly decreased in the group of patients with chronic lymphocytic leukemia treated with cytostatic drugs. Most pronounced decreased occurred in erythrocytes of patients with dyserythropoetic anemia.

Pepsinogens A and C: purification from human gastric mucosa and determination in serum by optimized radioimmunoassays.

Pepsinogen A and pepsinogen C were purified from human gastric mucosa. The preparations were immunochemically homogeneous and contained only their characteristic components. Specific, sensitive, and reliable radioimmunoassays for both pepsinogen A and pepsinogen C were developed. The concentration of pepsinogens in serum was log distributed. In 144 healthy control subjects the mean level of pepsinogen A (means +/- s) was 65.7 ng/ml (range: 49.8-86.6 ng/ml), significantly higher than the level of pepsinogen C (means = 12.2 ng/ml, range 9.2-16.1 ng/ml, p less than 0.001), with a Pg A/Pg C ratio of 5.8 +/- 2.7. In contrast, pepsinogen C was predominant in the serum of 26 patients with pernicious anemia. Since the mean level of the proenzyme (means = 10.2 ng/ml, range 7.7-13.4 ng/ml) did not differ (p greater than 0.05) from that of the control group, whereas the concentration of pepsinogen A was significantly lower (means = 6.1 ng/ml, range 3.7-9.5 ng/ml, p less than 0.001), the Pg A/Pg C ratio dropped to 0.6 +/- 0.3 (p less than 0.001). In 27 patients with total gastrectomy the levels of both pepsinogen A (means = 2.5 ng/ml, range 2.2-2.8 ng/ml) and pepsinogen C (means = 1.9 ng/ml, range 1.3-2.9 ng/ml) were significantly lower (p less than 0.001) than in patients with pernicious anemia. The results indicate that the stomach is the main source of serum pepsinogens, that under normal conditions the gastric chief cells release more pepsinogen A than pepsinogen C, and that only small amounts of the proenzymes originate from extragastric tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Parietal cell antibodies in pernicious anemia inhibit H+, K+-adenosine triphosphatase, the proton pump of the stomach.

Antibodies to a membrane-bound antigen, localized to the canalicular structures of the parietal cell, are found in most sera of patients with chronic atrophic gastritis and pernicious anemia. In the present study immunoglobulins containing parietal cell antibodies were found to inhibit the activity of H+,K+-adenosine triphosphatase (EC 3.6.1.36) in a tubulovesicular membrane preparation from porcine gastric mucosa. The degree of inhibition correlated to the titer of parietal cell antibodies as assessed by an enzyme-linked immunosorbent assay. The specificity of the enzymatic inhibition was confirmed by the lack of effect of parietal cell antibodies on membrane-bound esterase. A possible interaction of parietal cell antibodies with gastrin binding at the receptor level was investigated in a radioreceptor assay employing 125I-gastrin 1 and gastric mucosal cell suspension from the guinea pig. No blocking capacity was found with immunoglobulins from patients with pernicious anemia as compared with immunoglobulins from healthy controls. The results thus demonstrate a direct inhibitory effect of parietal cell antibodies on the acid producing H+,K+-adenosine triphosphatase of the parietal cell, but also a lack of interaction with the gastrin receptor, and indicate that in the development of hypo/achylia H+,K+-adenosine triphosphatase autoantibodies could have a major pathogenic role.

Hematopoietic and gastric uracil-DNA glycosylase activity in megaloblastic anemia and in atrophic gastritis with special reference to pernicious anemia.

The activity of the DNA excision repair enzyme uracil-DNA glycosylase was measured in peripheral blood mononuclear cells and in bone marrow aspiration samples obtained from patients with pernicious anemia (PA) or other types of megaloblastic anemia (one case of tapeworm anemia and three cases of myelodysplastic syndromes). In addition, the expression of uracil-DNA glycosylase was investigated in biopsies from the antrum and body of the stomach obtained from nine PA patients, from five patients having atrophic gastritis (AG) not associated with PA, and from six control patients having transient upper abdominal complaints without AG. Our results revealed that there was a considerable interindividual variation in gastric uracil-DNA glycosylase activity. No clear correlation between the enzyme level and the level of gastric atrophy was noted, although AG is generally regarded as a risk factor of gastric cancer. Furthermore, uracil-DNA glycosylase activities in peripheral blood mononuclear cells and in bone marrow cells in PA and in myelodysplastic syndromes were similar to the activities observed previously in non-hematological patients and healthy persons. Transient uracil incorporation into DNA may have a role in the cellular abnormalities associated with megaloblastic hematopoiesis. The present findings demonstrated that the enzymatic activity required for rapid removal of uracil from DNA is also expressed in the megaloblastic state.

Application of an in vitro assay for serum thymidine kinase: results on viral disease and malignancies in humans.

An improved method for the detection of deoxythymidine kinase (TK) in human sera is reported. The method which utilizes 125I-iododeoxyuridine (IdUrd) as a substrate was used to measure TK in sera from patients with different diseases. Sera collected during the acute stage of infectious mononucleosis were found to contain elevated levels of TK, in most cases 10-40 times the normal value. The serum TK activity disappeared gradually and reached a normal level within 4 weeks. Sera from patients with other viral infections contained in most cases normal serum TK levels except in connection with measles, rubella, varicella, herpes simplex virus and cytomegalovirus infections. Additional studies revealed that sera from patients with different types of advanced lymphomas, acute leukemias, chronic granulocytic leukemia and lung cancer of the small-cell type with metastases, contained high TK levels which fluctuated in parallel with alterations in activity of the disease. The TK activity in sera from patients with both mononucleosis and tumor disease was characterized by electrophoresis and by its ability to utilize cytidine triphosphate as the phosphate donor. The results showed that the serum TK has the same properties as the human cytosolar TKI, except in connection with varicella.

Serum lysozyme in inflammatory gastric and enteric diseases and in functional dyspepsia.

Serum lysozyme was reevaluated in inflammatory bowel disease and other gastrointestinal disorders. A total of 109 patients were divided into six groups: ulcerative colitis (28), Crohn's disease (9), simple atrophic gastritis (16), atrophic gastritis and pernicious anemia (23), functional dyspepsia (17), and controls (16). Elevated levels of lysozyme, compared with control levels, were found not only in ulcerative colitis and Crohn's disease but also in atrophic gastritis with or without pernicious anemia and in functional dyspepsia. The elevation of lysozyme, since it results from the product of granulocytes and macrophages present in increased amounts in the mucosa of inflammatory bowel diseases, is easily explained. The cellular infiltration in atrophic gastritis may also explain the elevated lysozyme levels. The higher lysozyme levels in some patients with functional dyspepsia could possibly reflect an underlying latent inflammatory process.

Determination of 'total' and 'true' cobalamin with the SimulTRAC Assay.

The determination of 'total' and 'true' cobalamin (the SimulTRAC Assay, Becton Dickinson) has been compared with other laboratory tests and with clinical symptoms typical of cobalamin deficiency. Patient specimens (n = 5709) were analysed for total cobalamin which was measured by its binding to a crude hog intrinsic factor preparation in the radioisotope assay. Specimens with borderline values (150-225 pmol/l) were reanalysed for true cobalamin in order to find out whether there were patients with cobalamin deficiency and a low true cobalamin content in serum. Of 803 patient sera with total cobalamin values between 150-225 pmol/l two patients had low true cobalamin values (less than 110 pmol/l) and typical laboratory and clinical signs of cobalamin deficiency. On the other hand three patients in this range had laboratory and clinical signs of cobalamin deficiency and significantly higher values with true than with total cobalamin. Measurement of true cobalamin is therefore not an unequivocal way to detect patient sera from patients with a cobalamin responsive anaemia. Analysis of true cobalamin does not seem to increase the sensitivity and specificity for cobalamin deficiency.

Distribution of erythrocyte nucleotides in pyrimidine 5'-nucleotidase deficiency.

In pyrimidine 5'-nucleotidase deficiency, erythrocytes contain elevated levels of pyrimidine nucleotides. The composition of this nucleotide pool was examined by ion exchange chromatography on Dowex formate columns using a linear ammonium formate elution gradient. In contradistinction to normal erythrocytes, adenine nucleotides accounted for only 32% of the nucleotide pool. The remainder consisted of 50% cytidine and 16% uridine nucleotides. The remaining 2% was not identified. The most abundant compound appeared to be UDP glucose whilst high levels of CTP, CMP and an unidentified cytidine compound less polar than CMP accounted for most of the cytidine nucleotide pool. The possibility that the abnormal nucleotides were due to an elevated reticulocyte count was excluded and it was also shown that erythrocytes from subjects heterozygous for pyrimidine 5'-nucleotidase deficiency did not have detectable levels of the abnormal nucleotides.