Survival following an acute coronary syndrome: a pet theory put to the test.

OBJECTIVE: The aim of this study was to revisit findings from previous studies reporting that pet ownership improves outcome following an admission for acute coronary syndrome (ACS). METHOD: Four hundred and twenty-four patients admitted to a cardiac unit with an ACS completed questions regarding pet ownership in hospital. Rates of cardiac death and readmission were assessed 1 year following hospitalization. RESULTS: Pet owners were more likely to experience a death or readmission following their hospitalization, after controlling for key psychosocial and medical covariates. When dog and cat owners were considered separately, cat ownership was significantly associated with increased risk of death or readmission. CONCLUSION: In this independent study, pet ownership at baseline, and cat ownership in particular, was associated with increased cardiac morbidity and mortality in the year following an admission for an acute coronary syndrome, a finding contrary to previous reports.

Cell surface-bound elastase and cathepsin G on human neutrophils: a novel, non-oxidative mechanism by which neutrophils focus and preserve catalytic activity of serine proteinases.

Serine proteinases of human polymorphonuclear neutrophils play an important role in neutrophil-mediated proteolytic events; however, the non-oxidative mechanisms by which the cells can degrade extracellular matrix in the presence of proteinase inhibitors have not been elucidated. Herein, we provide the first report that human neutrophils express persistently active cell surface-bound human leukocyte elastase and cathepsin G on their cell surface. Unstimulated neutrophils have minimal cell surface expression of these enzymes; however, phorbol ester induces a 30-fold increase. While exposure of neutrophils to chemoattractants (fMLP and C5a) stimulates modest (two- to threefold) increases in cell surface expression of serine proteinases, priming with concentrations of lipopolysaccharide as low as 100 fg/ml leads to striking (up to 10-fold) increase in chemoattractant-induced cell surface expression, even in the presence of serum proteins. LPS-primed and fMLP-stimulated neutrophils have approximately 100 ng of cell surface human leukocyte elastase activity per 10(6) cells. Cell surface-bound human leukocyte elastase is catalytically active, yet is remarkably resistant to inhibition by naturally occurring proteinase inhibitors. These data indicate that binding of serine proteinases to the cell surface focuses and preserves their catalytic activity, even in the presence of proteinase inhibitors. Upregulated expression of persistently active cell surface-bound serine proteinases on activated neutrophils provides a novel mechanism to facilitate their egress from the vasculature, penetration of tissue barriers, and recruitment into sites of inflammation. Dysregulation of the cell surface expression of these enzymes has the potential to cause tissue destruction during inflammation.

Gas exchange and breathing pattern in women with postmenopausal bone fragility.

BACKGROUND: Little is known about the relationship between bone fragility and respiratory function. We hypothesized that women with osteoporosis or osteopenia, without cardio-pulmonary disease, have perturbations in the pattern of breathing and gas exchange. METHODS: In 44 women with bone fragility (BF, T score: < -1), and 20 anthropomorphically-matched control women (T score > -1) we compared pulmonary function tests, central respiratory drive (mouth occlusion pressure or P 0.1), pattern of breathing using optoelectronic plethysmograph and arterial blood gases at rest. RESULTS: Static pulmonary function was similar in BF subjects and controls. However, the arterial blood gas measurements differed significantly. The arterial pH was significantly higher in BF subjects than in controls (P < 0.001). The partial pressure of carbon dioxide (PaCO2) and oxygen (PaO2) in arterial blood were significantly lower in BF subjects than controls (P < 0.001 and P = 0.009, respectively). The BF subjects had a shorter inspiratory fraction compared with controls (P = 0.036). Moreover, T-scores were significantly inversely correlated with the alveolar-arterial gradient of oxygen (r = -0.5; P = 0.0003) and the arterial pH (r = -0.4; P = 0.002), and positively correlated with arterial PaO2 (r = 0.3; P = 0.01) and PaCO2 (r = 0.4; P = 0.002) among all subjects. CONCLUSION: In the absence of known cardio-pulmonary disease, BF is associated with statistically significant perturbations in gas exchange and alterations in the pattern of breathing including shortening of the inspiratory time.

Quantum proteolysis by neutrophils: implications for pulmonary emphysema in alpha 1-antitrypsin deficiency.

Traditional enzyme kinetics provide a poor explanation for the increased risk of lung injury in alpha 1-antitrypsin (AAT) deficiency. Millimolar concentrations of leukocyte elastase, when released from single azurophil granules of activated neutrophils, lead to evanescent quantum bursts of proteolytic activity before catalysis is quenched by pericellular inhibitors. Herein, we tested the possibility that quantum proteolytic events are abnormal in AAT deficiency. We incubated neutrophils on opsonized fluoresceinated fibronectin in serum from individuals with various AAT phenotypes, and then measured and modeled quantum proteolytic events. The mean areas of the events in serum from heterozygous individuals (Pi MZ and Pi SZ) were slightly, but significantly, larger than those in serum from normal patients (Pi M). In marked contrast, mean areas of events in serum from AAT-deficient individuals were 10-fold larger than those in serum from normal patients. Diffusion modeling predicted that local elastase concentrations exceed AAT concentrations for less than 20 milliseconds and for more than 80 milliseconds in Pi M and Pi Z individuals, respectively. Thus, quantum proteolytic events are abnormally large and prolonged in AAT deficiency, leading directly to an increased risk of tissue injury in the immediate vicinity of activated neutrophils. These results have potentially important implications for the pathogenesis and prevention of lung disease in AAT deficiency.

Resistance to arteriosclerosis in pigs with von Willebrand's disease. Spontaneous and high cholesterol diet-induced arteriosclerosis.

The aortas of 11 pigs (aged 1-3 yr) with homozygous von Willebrand's disease (vWd) were compared with those of 11 normal pigs of the same ages. Six of the controls exhibited multiple arteriosclerotic plaques with intimal thickening of 63-130 mum. In contrast, none of the pigs with vWd had multiple plaques, and only one had a lesion >2 mm in diameter. In a subsequent study, 3-mo-old pigs (11 controls and 7 with homozygous vWd) were placed on a 2% cholesterol diet for up to 6 mo. All of the controls developed arteriosclerotic plaques in the aorta, and in nine of the controls, at least 13% of the entire surface was involved. Intimal thickness ranged up to 390 mum. In contrast, four of the pigs with vWd did not develop such lesions, two developed arteriosclerotic lesions affecting 6 and 7% of the aortic surface, and the seventh had 13% of the aortic surface involved. Most of the pigs with vWd, however, developed flat fatty lesions in contrast to the normal pigs whether on the normal or the high cholesterol diet. There was blue staining of the flat fatty lesions when two pigs with vWd were injected with Evans blue dye antemortem. By electron microscopy, severe endothelial damage was apparent, but there was no intimal proliferation. The coincidence of the impaired platelet-arterial wall interaction and lack of arteriosclerosis in this bleeding disease is discussed.

Interaction between leukocyte elastase and elastin: quantitative and catalytic analyses.

Solubilization of elastin by human leukocyte elastase (HLE) cannot be analyzed by conventional kinetic methods because the biologically relevant substrate is insoluble and the concentration of enzyme-substrate complex has no physical meaning. We now report quantitative measurements of the binding and catalytic interaction between HLE and elastin permitted by analogy to receptor-ligand systems. Our results indicated that a limited and relatively constant number of enzyme binding sites were available on elastin, and that new sites became accessible as catalysis proceeded. The activation energies and solvent deuterium isotope effects were similar for catalysis of elastin and a soluble peptide substrate by HLE, yet the turnover number for HLE digestion of elastin was 200-2000-fold lower than that of HLE acting on soluble peptide substrates. Analysis of the binding of HLE to elastin at 0 degrees C, in the absence of significant catalytic activity, demonstrated two classes of binding sites (Kd=9.3x10(-9) M and 2.5x10(-7) M). The higher affinity sites accounted for only 6% of the total HLE binding capacity, but essentially all of the catalytic activity, and dissociation of HLE from these sites was minimal. Our studies suggest that interaction of HLE with elastin in vivo may be very persistent and permit progressive solubilization of this structurally important extracellular matrix component.

The cell biology of leukocyte-mediated proteolysis.

Leukocyte-derived proteinases have the capacity to degrade every component of the extracellular matrix, and thereby play fundamental roles in physiological processes. However, if the activity of these proteinases is uncontrolled or dysregulated, they have the capacity to contribute to tissue injury that potentially affects every organ in the body. Although there is a substantial literature on structure and activity of these proteinases when they are free in solution, until recently there has been little information about the cell biology of proteinases and their inhibitors. Recent studies, however, have identified several mechanisms by which inflammatory cells can degrade extracellular proteins in a milieu that contains high-affinity proteinase inhibitors.

Monocyte adherence to fibronectin: role of CD11/CD18 integrins and relationship to other monocyte functions.

Adherence of monocytes to extracellular matrix components is critical for their accumulation at sites of infection. To gain insight into the factors that regulate monocyte recruitment, we have studied monocyte adherence with regard to the regulatory effects of bacterial lipopolysaccharide (LPS) and the mechanisms involved; moreover, we have contrasted the phenotypes of adherent and nonadherent cells. Our results show that only a minor subpopulation of monocytes (20-25%) adhere spontaneously to fibronectin and that LPS stimulated a threefold increase in the proportion of adherent cells. Basal adherence and LPS-stimulated adherence of monocytes to fibronectin were substantially mediated by CD11/CD18 integrins. Further studies revealed that spontaneously adherent monocytes were 14-fold more actively phagocytic, released 1.6-fold more superoxide anion, and contained 20-fold more peroxidase activity than nonadherent cells, whereas LPS-adherent cells had an intermediate phenotype. These results indicate that LPS may enhance the accumulation of monocytes with an antimicrobial phenotype and thereby promote resolution of tissue infection.

Platelet function and coagulation in patients with Wilson disease.

Sixteen patients with Wilson disease (hepatolenticular degeneration) were studied from the hemostatic point of view, particularly with regard to platelet function. Five of the patients had a mild bleeding tendency that was characterized by easy bruising. Moderate thrombocytopenia was observed in three of the five bleeders and in two of the others. One bleeder was thrombocytotic and hyperfibrinogenemic. Bleeding times, platelet retention and prothrombin consumption were abnormal rarely. However, 15 of the 16 patients had some abnormality of platelet aggregation: one when adenosine diphosphate was added to platelet rich plasma, three when epinephrine was added, and the remainder when collagen was added. The collagen abnormalities were delayed or absent aggregation (five patients, four of whom were bleeders) and absence of a change of shape (12 of the 16 patients). Platelet aggregation was completely normal in only one patient.

Multiple genes code for high-molecular-mass rhoptry proteins of Plasmodium yoelii.

We have examined the number of genes coding for a group of high-molecular-mass rhoptry protein(s) in the malaria parasite Plasmodium yoelii, and studied variation in the gene family within the parasite's genome. A region of the genes was amplified using oligonucleotides based on conserved DNA sequences and the products cloned. The sequences could be divided into 7 groups by restriction-fragment-length polymorphism. Further variation was detected by sequence analysis; 11 different sequences were detected in the 16 clones analyzed. The genes in the family were distributed on 6 chromosomes probably at 9 or more loci.

Chromosomal organisation of a gene family encoding rhoptry proteins in Plasmodium yoelii.

The genomic organisation of the genes coding for a group of high molecular mass rhoptry proteins of the rodent malaria parasite Plasmodium yoelii YM was investigated using blotting, two dimensional gel electrophoresis and restriction fragment length analysis. The genes were found on chromosomes 1, 5, 6 and 10, with the possibility that related genes were also present on chromosomes 3 and 4. On chromosome 1 the genes were located close to one end, whereas they were present at both ends of chromosome 5, 6 and 10. Two genes, e3 and e8, that had been partially characterised previously were present on chromosomes 5 and 1, respectively. Based on an analysis of the 3' end of the genes, three subfamilies present on chromosomes 1, 5 and 6, and 10, respectively, were identified.

Structure of Sm25, an antigenic integral membrane glycoprotein of adult Schistosoma mansoni.

Sm25 is the principal antigen recognised by antibodies from mice protectively vaccinated with isolated tegumental membranes of adult Schistosoma mansoni. The full-length amino acid sequence of this protein has been deduced from the sequence of two cDNAs, one isolated by screening a cDNA library and the other, including the 5' end of the gene, amplified directly from adult worm RNA using the polymerase chain reaction. The predicted sequence represents a nascent polypeptide of Mr 21,500. Following cleavage of a predicted signal sequence, the Mr of the resulting polypeptide is 17,600. The polypeptide contains 2 potential sites for N-linked glycosylation and a hydrophobic domain at the C-terminus that could facilitate membrane association. Analysis of the mature gene product confirmed that Sm25 is an N-glycosylated integral membrane protein and that the Mr of the deglycosylated polypeptide is between 15,000 and 20,000.

The turnover in normal dogs of prothrombin and its fragments; effect of induced intravascular coagulation.

When 125I-labeled canine prothrombin was given to normal adult dogs intravenously, it was calculated that 240% of the plasma prothrombin crossed the capillary barrier per day, 410% of the interstitial prothrombin returned to the blood stream daily, and 79% of the plasmatic prothrombin was catabolized per day. These data are in close agreement with those observed for bovine prothrombin in calves by Takeda (1970). When derived from normal dog prothrombin, prethrombin-1 is a mixture of 2 polypeptides, one larger than the other, and both present in about equal amounts. The longer peptide, "prethrombin-1-long," was catabolized twice as fast as prothrombin, and the shorter, "prethrombin-1-short," 4 times faster. Prothrombin fragment-1 was catabolized by the normal dog still more rapidly. The catabolism of prothrombin was not accelerated in 3 dogs receiving continuous infusions of a thromboplastic emulsion of dog brain. Nor was the level of prothrombin in their plasma remarkably altered.

Copper metabolism after biliary fistula, obstruction, or sham operation in rats.

Intravenously administered carrier-free 67Cu appeared rapidly in the bile of rats with a recently created biliary fistula; maximal excretion occurred within the first 2 hours. However, if the biliary fistula had been created 3 or 4 days before injection of the 67Cu, only one-fourth to one-half as much of the isotope appeared in the bile. There also was a small decrease in stable biliary copper. When rats with biliary fistula were compared with rats with permanent biliary obstruction, over a period of 6 weeks, both exhibited a marked increase in plasma copper and an equally pronounced increase in the rho-phenylenediamine oxidase activity of plasma but no increase in hepatic copper. Peaks in blood were reached within 2 weeks and then slowly diminished. Sham-operated rats had parallel, but much lower, copper and enzyme changes. Correlations between these rat studies and the copper retention of Wilson's disease and of primary biliary cirrhosis are suggested.

Quantitative bleeding time (hemorrhagometry). A review.

Accurately determining the amount of blood lost during bleeding time tests has been little exploited. Equipment is now available for measuring both the time and volume automatically--a technique called hemorrhagometry. This quantitative procedure has generated a number of interesting and unsuspected observations. Bleeding times lengthen and blood loss is exaggerated as the skin is cooled. This is particularly true of patients who have hemostatic defects, such as hemophilia A; Not only is the hemophiliac different from normal in this regard but, in Sutor's preliminary observations, the asymptomatic carrier of hemophilia A also seems to be distinguishable from the noncarrier on this basis. The test seems potentially useful in evaluating the effect of drugs on platelet function and in assessing mild bleeding diatheses. Variations induced by either warming or cooling the skin may well have clinical applicability.

The spectrum of von Willebrand's disease revisited.

We have examined nine patients with presumed von Willebrand's disease who present the spectrum of that disorder. Two had findings that would be accepted generally as diagnostic of von Willebrand's disease, and seven had variations of the usual pattern. The commonest variation was the combination of borderline and variable levels of coagulant Factor VIII, commensurate levels of Factor VIII-related antigen, and low levels of ristocetin-Willebrand factor.

Prothrombin Quick. A newly identified dysprothrombinemia.

The rarest of reported inherited plasmatic coagulopathies involve prothrombin. Only 10 families with significant reductions of this plasma protein (hypoprothrombinemia) have been observed. Even fewer, six families, have been found to have a functionally abnormal prothrombin (dysprothrombinemia) in their blood. An as yet undefined prothrombin abnormally has been recognized in eight other families. One of the first patients previously identified by Quick and his associates as having a defect in her plasma prothrombin has been shown to have about half the normal amount of prothrombin antigen but virtually no prothrombic function. We propose that this dysprothrombin be designated prothrombin Quick. An additional patient also first described by Quick was found to be truly hypoprothrombinemic--that is, to lack both functional and antigenic prothrombin. Briefly summarized are the other five families with dysprothrombinemia, nine with hypoprothrombinemia, and the eight in whom the defect has not been classified.

Hemostatic evaluation of patients undergoing liver transplantation.

A detailed coagulation and thromboelastographic study was done on the first 50 liver transplantation procedures performed at the Mayo Clinic between March 1985 and June 1986. Most of the patients suffered from primary sclerosing cholangitis, primary biliary cirrhosis, or chronic active hepatitis. Seven patients required a second liver transplantation, and six patients died, none intraoperatively. Most of the patients had distorted hemostatic mechanisms preoperatively, as would be expected because the liver generates most of the clotting factors. The outstanding exception was factor VIII, which was usually in the high-normal range or even more elevated. Substantial deterioration of coagulation factors occurred regularly during reperfusion of the donor liver. In some instances, this trend was corrected within 1 hour, but platelet counts continued to decrease, and some coagulation factors rebounded only partially. Because thromboelastographic tracings are quickly available to the liver transplant team and because they tend to forewarn of impending hemostatic problems, we believe that thromboelastography is a reasonably effective procedure for monitoring coagulation during liver transplantation.

Hypofibrinogenemia-dysfibrinogenemia and von Willebrand's disease in the same family.

Two Puerto Rican families were studied. One family included a number of members with dysfibrinogenemia occasionally associated with hypofibrinogenemia. The second family had members with von Willebrand's disease. The two diseases merged in the proband's immediate family; the affected members of this family exhibited a mild bleeding disorder. Others in the two families had no obvious bleeding tendency.

Evaluation of preoperative hematology-coagulation screening in liver transplantation.

We retrospectively reviewed the results of preoperative hematology-coagulation studies in 66 patients who underwent orthotopic liver transplantation-24 with the primary diagnosis of chronic active hepatitis (CAH), 22 with primary sclerosing cholangitis (PSC), and 20 with primary biliary cirrhosis (PBC). The mean prothrombin time was above normal in all three diagnostic groups, patients with CAH having the highest values. The mean activated partial thromboplastin time was normal in patients with PSC or PBC but elevated in those with CAH. Fibrinogen levels were above normal in patients with PBC but decreased in 1 patient (5%) with PSC and 10 (42%) with CAH. Mean platelet counts were below normal in 68% and 55% of patients with PSC and PBC, respectively, but in 96% of those with CAH. The mean Ivy bleeding time was normal in patients with PSC or PBC but prolonged in those with CAH. Patients with PSC or PBC had normal mean activity levels of factors II, V, VII, IX, and X, whereas those with CAH had below normal mean values for factors II and VII. The antithrombin III activity level was normal in patients with PSC or PBC but reduced in those with CAH. Thus, patients with CAH have a greater derangement in results of clotting studies in comparison with those who have PSC or PBC, but the use of blood did not differ among the three diagnostic groups.