Thrombomodulin, an endothelial anticoagulant protein, is absent from the human brain

Protein C activation by thrombin is significantly accelerated by the endothelial cell cofactor, thrombomodulin. In this study, we have developed a radioimmunoassay for thrombomodulin and have measured the cofactor content in several human tissues. The assay method detects as little as 2 ng of thrombomodulin. The highest thrombomodulin content was found in lung and placenta, but the antigen was also detected in spleen, pancreas, liver, kidney, skin, heart, and aorta. Unexpectedly, thrombomodulin was absent from brain. Extracts from cerebral cortex, cerebellum, centrum semiovale, midbrain, basal ganglia, pons, and medulla were devoid of thrombomodulin. In contrast, thrombomodulin antigen is present in extracerebral intracranial vessels, including basilar and internal carotid arteries and choroid plexus, as well as in endothelium of the pia-arachnoid.     

Perioperative Quality Initiative consensus statement on intraoperative blood pressure,risk and outcomes for elective surgery

Background

Intraoperative mortality is now rare, but death within 30 days of surgery remains surprisingly common. Perioperative myocardial infarction is associated with a remarkably high mortality. There are strong associations between hypotension and myocardial injury, myocardial infarction, renal injury, and death. Perioperative arterial blood pressure management was thus the basis of a Perioperative Quality Initiative consensus-building conference held in London in July 2017.

In vivo and in vitro MR imaging of renal tumors: histopathologic correlation and pulse sequence optimization

Magnetic resonance (MR) imaging has given mixed results in the detection of renal masses. To identify the reasons for this and to determine the optimal pulse sequences for evaluating renal tumors, the authors imaged 12 primary renal tumors in vivo and 17 in vitro at 0.35 T. Histopathologic findings for each specimen were closely correlated with the MR images. Four of seven solid tumors imaged in vivo were isointense with surrounding normal renal parenchyma at all pulse sequences. The other three tumors were hyperintense in vivo at T2-weighted sequences. At heavily T2-weighted sequences eight solid tumors were hyperintense in vitro and four were hypointense. There was no correlation between signal intensity and specific tissue type or histologic pattern for solid tumors. The five cystic tumors were well seen both in vivo and in vitro on T2-weighted images. However, the signal intensity of the cyst fluid was an unreliable indicator of benignancy. SE MR imaging at 0.35 T has significant limitations in the detection of solid renal masses.     

Human platelet cytoskeletons: specific content of glycolipids and phospholipids

The lipid composition of platelet cytoskeletons was analyzed. Triton X- 100 (0.5%) was used to prepare cytoskeletons from thrombin-treated platelets. The lipid/protein ratio of platelet cytoskeletons was 0.260 and the phospholipid/protein ratio was 0.177, which were comparable to the ratios present in platelets. However, there was a selective enrichment of platelet lipids in platelet cytoskeletons. Only 2 of the 5 major platelet phospholipids were detected. About 14% platelet sphingomyelin and 2% platelet phosphatidylcholine were present in platelet cytoskeletons. Only 1 of the 4 platelet neutral glycolipids, trihexosyl ceramide, was detected and was about 7% of that in intact platelets. Two percent of platelet hematoside, the predominant ganglioside in platelets, was found in cytoskeletons. Six percent of platelet cholesterol was present in platelet cytoskeletons, while no other neutral lipid could be detected. The study demonstrates that the lipid/protein ratio of platelet cytoskeletons is similar to that in platelets, but the composition of cytoskeleton lipids is specific and distinctly different from that in platelets. The selective glycolipid and phospholipid composition of cytoskeletons may be important for cytoskeleton and platelet function.     

Detecting fetomaternal hemorrhage: a comparison of five methods

Appropriate postpartum administration of Rh immune globulin relies on sensitive detection and accurate quantitation of fetomaternal hemorrhage (FMH). Recently, the microscopic Du test (micro Du) enhanced with polyethylene glycol (PEG Du) and flow cytometry (FC) have been advocated for this purpose. Three qualitative methods (micro Du, rosette test, and PEG Du) and two quantitative methods (acid elution and FC) for assessing FMH were evaluated with particular attention given to PEG Du and FC. In vitro studies comprised 10 series of dilutions of D+ cord cells in D- adult cells to yield D+ cell concentrations of 0.06, 0.12, 0.25, 0.50, 0.75, 1.0, and 2.0 percent. Additionally, 26 postpartum samples were tested. Of the qualitative techniques, the micro Du test was the least sensitive with 20 percent false-negative results occurring at 0.5 percent fetal cells. The PEG Du test was only slightly more sensitive and offered no clinical advantage. The rosette test was the most sensitive, consistently detecting fetal cells at concentrations of 0.25 percent or greater. FC and acid elution showed similar results, with good correlation obtained between measured and expected quantities of fetal cells (r = 0.99 and 0.96, respectively). One of 26 postpartum samples was positive by all screening techniques; acid elution and FC detected 0.3-percent concentrations of fetal cells and 0.17-percent concentrations of D+ cells, respectively. Although acid elution is a more commonly used method for quantitating FMH, FC offers an acceptable alternative that is capable of analyzing large numbers of cells with objectivity and reproducibility.     

Activation of the contact system in insect-sting anaphylaxis: association with the development of angioedema and shock

A postulated role of the contact system in anaphylactic reactions to insect stings was investigated. During prospective, in-hospital sting challenge, we collected serial blood samples from five normal volunteers and 16 patients with a history of insect-sting anaphylaxis. Activation of the contact system was assessed by measuring plasma levels of factor XIIa-C1-inhibitor and kallikrein-C1-inhibitor complexes as well as those of cleaved high molecular weight kininogen (HK). In addition, antigenic levels of (pre)kallikrein, factor XII, and HK were measured. No significant changes in contact system parameters were observed in any of the five volunteers or the four patients who did not develop an anaphylactic reaction after sting challenge. In contrast, significant changes in contact system parameters occurred in 7 of the 12 patients with anaphylactic symptoms after challenge. Peak levels of either C1-inhibitor complex were found 5 minutes after the onset of anaphylactic symptoms. The increase in C1-inhibitor was most pronounced in the 4 patients with angioedema, 2 of which also developed shock. However, activation of HK was observed in all four patients with angioedema, the two patients with shock but no angioedema, as well as in 1 of the remaining 6 patients with anaphylactic symptoms other than angioedema or shock. Thus, activation products of the contact system may be involved in the pathogenesis of angioedema and shock in insect- sting anaphylaxis.     

Combined procoagulant activity and proteolytic activity of acute promyelocytic leukemic cells: reversal of the bleeding disorder by cell differentiation

In the human promyelocytic cell line HL60, we observed both a strong procoagulant activity (PCA) on the cell membrane and proteolytic activity in the lysate of these cells. Because these cell-line cells are susceptible to differentiation to either a more mature granulocytic or monocytic form, we were able to study the hypothesis that the combination of PCA and proteolytic activity is confined to the promyelocyte. This may explain the severe coagulopathy seen in patients with acute promyelocytic leukemia. Cell differentiation in a myeloid direction induced by retinoic acid or DMSO led to a diminished PCA, while not affecting the fibrinolytic activity. On the other hand, monocytic differentiation obtained by culturing the cells in the presence of 1; 25 dihydroxy vitamin D3 led to the complete disappearance of the proteolytic activity of the cell lysate, although the procoagulant activity was still present. Furthermore, we found that the elastase activity almost disappeared after monocytic differentiation. We also studied the PCA, proteolytic activity, and elastase activity of blast cells of patients with acute myeloid leukemia. Only in patients with acute promyelocytic leukemia did we observe both a strong PCA and fibrinolytic activity. This supports our hypothesis that the combination of these activities is unique to the promyelocyte and may explain the observed bleeding complications in patients with acute promyelocytic leukemia.     

Gamma heavy chain disease: rapid, sustained response to cyclophosphamide and prednisone

A patient, CAL, with gamma heavy chain disease is presented who has had a complete remission lasting over 2 yr with combination chemotherapy consisting of pulsatile cyclophosphamide and prednisone. The patient exhibited many features of an atuoimmune process including a vasculitis, low serum complement levels, a positive antiglobulin (Coombs) test, Raynaud's phenomenon, and keratoconjunctivitis sicca. The CAL paraprotein was found to have several previously undescribed characteristics. It reacted with antisera to Fd, Fab, and Fab', suggesting that most of the Fd portion of the molecule was intace. CAL protein consists of two polypeptide chains of molecular weight 49,000 covalently linked to form a dimer of 95,000 molecular weight. The covalent linkage suggests that the hinge region of this gamma heavy chain is intact.     

Impaired interleukin-3 response in Pim-1-deficient bone marrow-derived mast cells

The mouse Pim-1 gene encodes two cytoplasmic serine-threonine-specific protein kinases. The gene has been found to be activated (overexpressed) by retroviral insertion in hematopoietic tumors in mice. Transgenic mice that overexpress Pim-1 (E mu-Pim-1) have a low incidence of spontaneous T-cell lymphomas and an increased susceptibility to Moloney murine leukemia virus and N-ethyl-N- nitrosourea-induced lymphomas. Apart from a slight enlargement of the spleen, no abnormalities were found in prelymphomatous transgenic mice. Inactivation of the Pim-1 gene in the germline of mice resulted in mice with a surprisingly subtle phenotype. Therefore, we investigated whether subtle effects of the absence of Pim-1 could be made visible during in vitro culturing of hematopoietic cells. We found that bone marrow-derived mast cells (BMMC) lacking Pim-1 had a distinct growth disadvantage when grown on interleukin (IL)-3, but not when stimulated by the factors IL-4, IL-9, or Steel factor (SF). This indicates a role for Pim-1 as a modulator of the IL-3 signal transduction pathway.     

Elevated adenosine deaminase and purine nucleoside phosphorylase activity in peripheral blood null lymphocytes from patients with acquired immune deficiency syndrome

The purine metabolic enzymes adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) are important in lymphocyte differentiation, and genetic deficiencies of either enzyme have been associated with hereditary immunodeficiency states. Both ADA and PNP activity were measured in null cell-enriched and T cell-enriched peripheral blood lymphocytes from 16 patients with the acquired immune deficiency syndrome (AIDS), seven patients with the AIDS-related symptom complex (ARC), and seven asymptomatic homosexuals. ADA activity in nmol/10(6) lymphocytes/h was significantly elevated in null lymphocytes from AIDS (161 +/- 12) as compared with 23 healthy heterosexual controls (127 +/- 8;P less than .025). PNP activity was also significantly increased in null lymphocytes from AIDS patients (96 +/- 10;P less than .005) as well as those from ARC patients (84 +/- 11:P less than .025) relative to controls (61 +/- 5). No significant differences in enzyme activity were noted in T cell-enriched cells in any group. Along with elevated enzyme activity, AIDS patients had small yet significant increases in the percentages of HLA-DR (P less than .025), terminal deoxynucleotidyl transferase (TdT) (P less than .0001), and peanut agglutinin receptor (P less than .0001) positive lymphocytes in the null fraction compared with controls. TdT-positive cells appeared morphologically as large lymphoblasts with irregular nuclei. The data imply that the cellular immune deficiency in AIDS is not a result of deficiencies in lymphocyte ADA or PNP activity, but is more likely associated with an increase in an immature and/or activated lymphocyte subset.