Bleeding disorder due to platelet prostaglandin H synthase-1 (PGHS-1) deficiency.

Defective platelet prostaglandin H synthase (PGHS) activity has been recognized as a cause of bleeding disorders, but the defect has not been characterized. We evaluated three female patients aged 37, 48 and 55 who presented with a mild bleeding disorder due to platelet dysfunction. None of the patients had underlying diseases or reported use of aspirin or other nonsteroidal anti-inflammatory drugs. Coagulation screening tests and platelet count were normal in each patient. Platelet aggregation in response to adenosine diphosphate (ADP), collagen and epinephrine were subnormal, characterized by an abnormal second-wave aggregation and propensity for disaggregation. Arachidonate-induced platelet aggregation was defective, whereas PGH2-induced aggregation was normal. Platelet thromboxane A2 (TXA2) production in response to arachidonic acid was reduced in all three patients, i.e. 11.7, 4.6 and 4.4 ng TXB2/3 x 10(8) plt respectively (normal range was 49-81 ng/3 x 10(8) plt), whereas they were normal in response to exogenous PGH2, i.e. 71.4, 56.6 and 48.9 ng/3 x 10(8) respectively (normal range 49-85 ng/3 x 10(8) plt). These results are consistent with a deficiency of platelet PGHS activity. The level of the constitutive platelet PGHS-1 and TXA2 synthase (TXAS) proteins were determined on platelet microsomal fractions by Western blot analysis using affinity-purified polyclonal antibodies highly specific for human PGHS-1 and TXAS, respectively. In two patients the 70 kD PGHS-1 protein was undetectable, whereas it was normal in the third patient. The 60 kD TXAS band was normal in all three patients. These findings indicate that human platelet PGHS-1 deficiency is due to two types of enzyme defects: type 1 defect is manifested by an undetectable PGHS-1 protein in platelets whereas the type 2 defect is manifested by a normal quantity of PGHS-1 protein which has an impaired catalytic activity.

Enalapril treatment of posttransplant erythrocytosis: efficacy independent of circulating erythropoietin levels.

To determine the mechanism of action by which angiotensin-converting enzyme (ACE) inhibitors lower hematocrit in patients with posttransplant erythrocytosis, indices of red blood cell production and red blood cell destruction were obtained serially for 6 months from 10 renal transplant patients receiving treatment with enalapril for this problem. Before treatment, five patients had an elevated red blood cell mass, four had plasma volume contraction, and one had both. The mean hemoglobin concentration decreased by 2 g/dL (range, 0.5 to 3.3 g/dL), from 17 +/- 1 g/dL to 15 +/- 1 g/dL (P = 0.001) following 6 months of enalapril therapy. Similarly, the mean hematocrit decreased by 8% (range, 3% to 12%), from 52% +/- 2% to 44% +/- 3% (P = 0.001) during the same period. The mean reticulocyte count tended to decrease, although the change was not significant. The red blood cell mass decreased dramatically by 15% to 50%, from 32 +/- 9 mL/kl to 23 +/- 4 mL/kg (P = 0.008). Although serial erythropoietin levels declined steadily in two patients, there was no consistent change in the other patients. Mean levels decreased modestly, from 20 +/- 11 mU/mL at baseline to 12 +/- 5 mU/mL at 6 months, a change that was not statistically significant. Mean levels at each time point were not statistically different from the mean pretreatment value. Furthermore, during enalapril therapy, there was no correlation between mean circulating erythropoietin level and mean hematocrit (r = 0.43, P = 0.20) or hemoglobin concentration (r = 0.36, P = 0.30) or between changes in these parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Ancylostoma factor Xa inhibitor: partial purification and its identification as a major hookworm-derived anticoagulant in vitro.

Soluble protein extracts from adult Ancylostoma hookworms were found to contain an anticoagulant activity that markedly prolonged both the prothrombin time (PT) and partial thromboplastin time (PTT). By chromogenic peptide substrate and clotting time assays, the anticoagulant activity was attributed to a specific inhibitor of clotting factor Xa. The hookworm anticoagulant was partially purified by ion-exchange column chromatography. Those column fractions containing anti-Xa activity by chromogenic assay also prolonged the PT and PTT as well as the factor X (Stypven) clotting time. These data suggest that this potent factor Xa inhibitor is a major anticoagulant from the adult Ancylostoma hookworm.

Successful childbirth by a patient with congenital factor XI deficiency and an acquired inhibitor.

Acquired inhibitors in factor XI deficiency (FXI) are rare. The presence of an inhibitor during pregnancy poses a potential haemorrhagic risk to the fetus. We report an uncomplicated pregnancy and successful childbirth by a woman with congenital FXI deficiency and an acquired inhibitor, and discuss the persistence of residual FXI activity in the presence of an inhibitor.

Morphologic, biochemical, and cytogenetic studies of bone marrow and circulating blood cells in painters exposed to ethylene glycol ethers.

In a previous cross-sectional survey, up to 15% of shipyard painters were found to have mild anemia or granulocytopenia, mostly acquired since employment. Environmental studies had suggested a possible etiologic role for ethylene glycol ethers, solvents to which the men were heavily exposed and which have established myelotoxic potential. To exclude alternative hypotheses, examine possible common patterns of injury, and identify potential risk factors and markers for such an effect, the affected painters were further studied. The painters were matched with two groups of controls: exposed painters without evidence of hematologic abnormality on the previous survey and unexposed controls. Altogether 25 subjects were studied by histopathologic examination of bone marrow, cytogenetic studies of marrow cells, and peripheral lymphocytes and peripheral red cell studies of membrane and metabolic function. Except for an unexpected finding of a race-associated effect on marrow histology, insignificant differences were seen among the groups in terms of marrow morphology and cellularity, stem cell growth kinetics, and marrow or peripheral cytogenetics. Two metabolic abnormalities of peripheral red cells related to exposure or clinical status of the subjects were found. Pyruvate kinase, an established marker of acquired myelodysplasia, was significantly depressed in the subjects with previously abnormal counts. Although reduced glutathione levels and holoenzyme activities of glutathione reductase (GSHR) did not differ among groups, exposed subjects had decreased saturation of GSHR with flavin adenine dinucleotide which could be restored in vitro, suggesting riboflavin deficiency or impaired riboflavin metabolism. Thus, although a unique pattern of bone marrow injury by histologic or genetic assay attributable to ethylene glycol ethers was not defined, biochemical effects of possible mechanistic importance were identified. The relevance of these findings as subclinical disease markers remains to be established.

A unique factor XIII inhibitor to a fibrin-binding site on factor XIIIA.

An 81-year-old woman, who presented with sudden episodes of spontaneous bleeding, was found to have a specific inhibitor of factor XIII. Her fibrin clots had approximately 70% gamma-gamma and no alpha polymer formation, under conditions where normal fibrin was fully cross-linked; the patient's clots were soluble in urea or monochloroacetic acid. Factor XIII activity in her plasma was 24%, measured by the dansylcadaverine incorporation assay. When mixed with normal plasma, the patient's plasma inhibited fibrin cross-linking; however, in mixtures of patient and normal plasma, there was no inhibition of factor XIII activity when assayed by the incorporation of dansylcadaverine into casein. Thus, this inhibitor was active against fibrin cross-linking but not against ligation of small molecules to casein. Consequently, gel electrophoresis of reduced, sodium dodecyl sulfate-solubilized fibrin clots was a simple, quantitative method that was used to measure inhibitor activity. This inhibitor is unique and has been designated inhibitor New Haven. It was neutralized by anti-IgG and anti-kappa. It did not inhibit the activation of factor XIII but did inhibit fibrin cross-linking. There was complex formation between the inhibitor and activated factor XIII (A', A*) but not between A2 or fibrinogen. Only A', A* and the 56-Kd fragment bound to affinity columns made with this IgG. The inhibitor significantly decreased the binding of A', A* to fibrin clots. These data indicate that the epitope for this inhibitor is in a fibrin binding site. It is hidden in the zymogen and expressed on A' and A*, indicating that the conformational change occurring with the cleavage of the activation peptide is sufficient to expose the fibrin binding site.

Reevaluation of the periodic acid-Schiff stain in acute leukemia with immunophenotypic analyses.

To determine the sensitivity and specificity of the periodic acid-Schiff (PAS) stain in the diagnosis of acute leukemia in light of the finer characterization of this disorder now available through immunophenotyping, we examined the blasts from 51 patients with newly diagnosed acute leukemia by morphological, cytochemical, and immunophenotypic analyses. The 51 patients represented every new case of acute leukemia subjected to cytochemical stains and flow cytometry between July 1987 and February 1989. By cell-surface marker analysis, 29 exhibited lymphocytic lineage, while 21 were myelocytic. One was mixed lineage. The PAS positivity, defined by the presence of blocks or coarse granules in 5% or more of the blasts, was found in 15 of 29 lymphoblastic leukemias and in four of the myeloblastic leukemias. However, PAS-positive lymphoblastic leukemias were negative with the other cytochemical stains: myeloperoxidase, Sudan black B, and alpha-naphthyl butyrate esterase. The PAS-positive myeloblastic leukemias were positive with at least one other stain. Three cases of myeloblastic leukemia exhibited greater than 10% PAS-positive blasts, with all three being acute monoblastic leukemia. Thus, the sensitivity and specificity of the PAS stain alone for lymphoblastic leukemia was 52% (15 true positives of 29) and 81% (four false positives), respectively. The sensitivity of a cytochemical-staining combination of PAS positivity and myeloperoxidase, Sudan black B, and alpha-naphthyl butyrate esterase negativity in defining cases of lymphoblastic leukemia remained at 52%; however, the specificity of this combination for lymphoblastic leukemia was 100% (no false positives). Thus, a positive PAS stain, in combination with negative myeloperoxidase, Sudan black B, and alpha-naphthyl butyrate esterase stains, continues to have a diagnostic role in the distinction between lymphoblastic and myeloblastic leukemia, and greater immunologic sophistication serves to support this position.

Whole blood serotonin in autistic and normal subjects.

Whole blood serotonin and tryptophan were measured in 87 normal subjects and in 40 autistic subjects. Whole blood serotonin concentrations (mean +/- SE) were significantly higher in drug-free (N = 21) autistics (205 +/- 16 ng/ml) than in normals (136 +/- 5.4 ng/ml). The Gaussian distribution of serotonin levels in the unmedicated autistic group suggests the elevation was not due to a subgroup of autistic subjects. Autistics medicated with anticonvulsants or neuroleptics had significantly lower serotonin levels than did drug-free autistic subjects. Whole blood tryptophan levels and platelet counts were similar in the autistic and normal groups. The possible causes of the hyperserotonemia of autism are discussed.

Relapsing malaria infection acquired in Kenya.

An American physician-traveler to East Africa presented with manifestations of cerebral malaria and was treated with intravenous quinidine for chloroquine-resistant falciparum malaria. He later relapsed with Plasmodium ovale infection, despite previous primaquine therapy. Treatment of chloroquine-resistant malaria is discussed. The difficulty in diagnosing P. ovale infections and the predominance of this malaria species over P. vivax in East Africa are reviewed.

Acute adrenal insufficiency as a complication of urological surgery.

Acute adrenal insufficiency postoperatively is an uncommon problem and, if unrecognized, it may cause serious morbidity and can be fatal. It can occur as the result of acute bilateral adrenal hemorrhage associated with anticoagulation, inadvertent injury to or removal of a solitary adrenal gland, or postoperative stress in an individual with incipient adrenal insufficiency. Its manifestations, such as fever, tachycardia, hypotension, lethargy, abdominal pain and gastrointestinal dysfunction, mimic the other more common postoperative complications and compound the difficulty in establishing the correct diagnosis. Once the diagnosis is made the condition is readily managed successfully. We report 3 cases of acute adrenal insufficiency occurring after salvage cystectomy, ileal replacement of the ureter and retropubic prostatectomy, which illustrate the salient clinical features, problems in diagnosis and predisposing risk factors. All 3 patients survived once the diagnosis of adrenal insufficiency was made. These cases emphasize the need to be aware of the possibility of this complication to make the correct diagnosis and to institute proper treatment.

Isoniazid-induced pure red cell aplasia.

The clinical courses of four individuals with pure red cell aplasia associated with isoniazid use are described. Erythroblastopenia in these individuals resolved following cessation of this antituberculous therapy. A clonal assay system that quantitates erythroid precursor cells was used to investigate the pathogenesis of the red cell aplasia in three of the patients. Using this technique, however, we were unsuccessful in demonstrating an inhibitory effect of acute phase serum, isoniazid or a combination of the two on erythroid colony formation. We conclude that isoniazid usage alone appears to be associated with a readily reversible form of acquired pure red cell aplasia. In addition, the results of our in vitro studies emphasize the limitations of bone marrow culture systems when used to implicate offending drugs in the production of drug related cytopenias.

Hemoglobin connecticut (beta 21 (B3) Asp leads to Gly): a hemoglobin variant with low oxygen affinity.

Electrophoretic analysis of a hemolysate from a young man undergoing a routine physical examination revealed an abnormal hemoglobin with a mobility similar to Hb S on cellulose acetate (pH, 8.4). This new variant, designated Hb Connecticut, was found in three generations of a family of Polish descent. Several individuals possessing the variant exhibited mild anemia. Structural analysis of the abnormal beta-chain indicated that the amino acid substitution was at position 21 (B3), and involved the replacement of aspartic acid with glycine. Oxygen dissociation studies revealed low oxygen affinity. The alkaline Bohr effect and the degree of cooperativity were unchanged. Analysis of the crystal structure of the variant suggested that the low oxygen affinity was due to the possible disruption of salt bridges between aspartic acid 21(B3) and lysines 61(ES) and 65(E9), changes that could lead to steric interference in oxygen binding.

Impaired renal tubular potassium secretion in sickle cell disease.

We examined renal tubular function in six patients with sickle cell hemoglobin. All had normal inulin and para-aminohippurate clearances and impaired urinary concentrating and acidifying abilities. After intravenous potassium chloride administration, maximum excretion of potassium (U,V) was significantly lower in sickle cell patients than in control subjects, and the percentage of potassium load excreted in 5 h was markedly reduced. Urinary potassium excretion after sodium sulfate infusion was also markedly reduced in sickle cell patients compared to control subjects. After 40 mg of oral furosemide, U,V was also diminished in sickle cell patients. Plasma aldosterone response to ACTH and intravenous potassium was similar to that of control subjects. Plasma renin activity increased normally after volume contraction. We conclude that sickle cell patients have a defect in their ability to excrete an acute potassium load that cannot be attributed to abnormal renin or aldosterone secretion. Overall potassium homeostasis is maintained by extrarenal mechanisms during acute potassium loading.

An improved turbidimetric method for plasma fibrinogen.

Our experience in the use of Ellis' and Stransky's turbidimetric technique for the determination of plasma fibrinogen is presented. We standardized the test using a plasma pool whose fibrinogen content was determined by a weighed clot technique. The turbidimetric-fibrinogen test is accurate, sensitive, specific, reproducible, convenient, and inexpensive. Correlations between the turbidimetric method and the weighed clot reference method was shown. The assay is sensitive to as little as 25 mg/dl plasma fibrinogen, and the results are not affected by samples with a high content of lipids, bilirubin, fibrin split products, lymphangiogram dye, or therapeutic levels of heparin. Day-to-day replicate determinations on a plasma pool yielded a coefficient of variation of 3.4 percent. Results from as many as 10 plasma samples can be obtained in 30 minutes (10-minutes working time). Reagent cost is less than one cent per test.