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Essentials Tissue factor (TF) isoforms are expressed in pancreatic neuroendocrine tumors (pNET). TF knockdown inhibits proliferation of human pNET cells in vitro. mTOR kinase inhibitor sapanisertib/MLN0128 suppresses TF expression in human pNET cells. Sapanisertib suppresses TF expression and activity and reduces the growth of pNET tumors in vivo. SUMMARY: Background Full-length tissue factor (flTF) and alternatively spliced TF (asTF) contribute to growth and spread of pancreatic ductal adenocarcinoma. It is unknown, however, if flTF and/or asTF contribute to the pathobiology of pancreatic neuroendocrine tumors (pNETs). Objective To assess TF expression in pNETs and the effects of mTOR complex 1/2 (mTORC1/2) inhibition on pNET growth. Methods Human pNET specimens were immunostained for TF. Human pNET cell lines QGP1 and BON were evaluated for TF expression and responsiveness to mTOR inhibition. shRNA were used to knock down TF in BON. TF cofactor activity was assessed using a two-step FXa generation assay. TF promoter activity was assessed using transient transfection of human TF promoter-driven reporter constructs into cells. Mice bearing orthotopic BON tumors were treated with the mTORC1/2 ATP site competitive inhibitor sapanisertib/MLN0128 (3 mg kg -1 , oral gavage) for 34 days. Results Immunostaining of pNET tissue revealed flTF and asTF expression. BON and QGP1 expressed both TF isoforms, with BON exhibiting higher levels. shRNA directed against TF suppressed BON proliferation in vitro. Treatment of BON with sapanisertib inhibited mTOR signaling and suppressed TF levels. BON tumors grown in mice treated with sapanisertib had significantly less TF protein and cofactor activity, and were smaller compared with tumors grown in control mice. Conclusions TF isoforms are expressed in pNETs. Sapanisertib suppresses TF mRNA and protein expression as well as TF cofactor activity in vitro and in vivo. Thus, further studies are warranted to evaluate the clinical utility of TF-suppressing mTORC1/2 inhibitor sapanisertib in pNET management., (© 2018 International Society on Thrombosis and Haemostasis.)

Objective: This study aimed to evaluate the role of 3 Tesla magnetic resonance imaging in predicting tongue tumour thickness via direct and reconstructed measures, and their correlations with corresponding histological measures, nodal metastasis and extracapsular spread., Methods: A prospective study was conducted of 25 patients with histologically proven squamous cell carcinoma of the tongue and pre-operative 3 Tesla magnetic resonance imaging from 2009 to 2012., Results: Correlations between 3 Tesla magnetic resonance imaging and histological measures of tongue tumour thickness were assessed using the Pearson correlation coefficient: r values were 0.84 (p < 0.0001) and 0.81 (p < 0.0001) for direct and reconstructed measurements, respectively. For magnetic resonance imaging, direct measures of tumour thickness (mean ± standard deviation, 18.2 ± 7.3 mm) did not significantly differ from the reconstructed measures (mean ± standard deviation, 17.9 ± 7.2 mm; r = 0.879). Moreover, 3 Tesla magnetic resonance imaging had 83 per cent sensitivity, 82 per cent specificity, 82 per cent accuracy and a 90 per cent negative predictive value for detecting cervical lymph node metastasis., Conclusion: In this cohort, 3 Tesla magnetic resonance imaging measures of tumour thickness correlated highly with the corresponding histological measures. Further, 3 Tesla magnetic resonance imaging was an effective method of detecting malignant adenopathy with extracapsular spread.

Alternatively spliced tissue factor (asTF) promotes neovascularization and monocyte recruitment via integrin ligation. While asTF mRNA has been detected in some pancreatic ductal adenocarcinoma (PDAC) cell lines and increased asTF expression can promote PDAC growth in a subcutaneous model, the expression of asTF protein in bona fide PDAC lesions and/or its role in metastatic spread are yet to be ascertained. We here report that asTF protein is abundant in lesional and stromal compartments of the five studied types of carcinoma including PDAC. Analysis of 29 specimens of PDAC revealed detectable asTF in >90% of the lesions with a range of staining intensities. asTF levels in PDAC lesions positively correlated with the degree of monocyte infiltration. In an orthotopic model, asTF-overexpressing high-grade PDAC cell line Pt45P1/asTF+ produced metastases to distal lymph nodes, which stained positive for asTF. PDAC cells stimulated with and/or overexpressing asTF exhibited upregulation of genes implicated in PDAC progression and metastatic spread. Pt45P1/asTF+ cells displayed higher coagulant activity compared to Pt45P1 cells; the same effect was observed for cell-derived microparticles (MPs). Our findings demonstrate that asTF is expressed in PDAC and lymph node metastases and potentiates PDAC spread in vivo. asTF elicits global changes in gene expression likely involved in tumor progression and metastatic dissemination, and it also enhances the procoagulant potential of PDAC cells and cell-derived MPs. Thus, asTF may comprise a novel therapeutic target to treat PDAC and, possibly, its thrombotic complications., (© 2013 UICC.)

Background: Metastasis to the pancreas (PM) is uncommon. Several types of cancers were reported to metastasize to the pancreas. Surgery is advocated in selected patients when technically feasible and if the patient can be rendered disease free., Methods: A retrospective review of PM patients at the University of Cincinnati Pancreas Database was performed over a 7-year time period., Results: Twenty patients with a median age of 62.5 years were identified. Fifteen patients (75%) were males and (50%) presented with abdominal pain. Nine patients (45.0%) were offered surgical resection, distal pancreatectomy was the most common procedure (n = 4, 44.4%). The commonest pathology was RCC (60%), followed by lung (20%), colon (15%), and breast (5%). Median disease free interval (DFI) was 96 months for RCC, 7 months for other pathologies. Median survival was 19 months for RCC, 8.5 months for other pathologies. Based on DFI, short DFI patients (≤12 months) had worse prognosis (2-year survival of 40%), as opposed to (2-year survival of 80%) in longer DFI patients (P = 0.01). RCC patients with a DFI longer than 94 months had a better survival (P = 0.01). Survival of resected PM tended to be longer than non-resected PM (P = 0.11)., Conclusions: PM from RCC carries a consistently favorable prognosis compared to other pathologies. Surgical resection of PM is a safe and viable option, and, in selected patients, may improve survival. However, a period of expectant management in patients with short DFI may be considered., (Copyright © 2011 Wiley Periodicals, Inc.)

Objective: To find out if clearance of surgical colectomy specimens with xylene gave a higher yield of lymph nodes and more accurate staging than the traditional step-sectioning technique., Design: Consecutive open study., Setting: Private hospital, United States., Material: 84 specimens from colonic resections, 4 of which were total colectomies and the remaining 80 segmental resections., Interventions: The first 41 (2 colectomies and 39 segmental resections) were cleared by step-sectioning alone (to establish baseline values). The remainder (n = 2 and 41, respectively) were step-sectioned, the lymph nodes were removed, and then the residual tissue was cleared with xylene., Main Outcome Measures: The number of lymph nodes found, and if the diagnosis was changed by the finding of additional nodes., Results: The baseline values in the two total colectomy specimens were 76 and 101, and the mean (range) after segmental colectomy was 21 (1-98). The values after total colectomy in the second group were 33 and 73, and after xylene clearance an additional 12 and 17 nodes were found. After segmental colectomy a mean (range) of 13 (0-43) was found, and an additional 4 (0-12) were found after xylene clearance. No additional nodes containing metastases were found in total colectomy specimens after xylene clearance, and only 6 additional nodes after segmental resection contained metastases. These changed the histological stage of the disease in only 2 patients., Conclusions: Xylene clearance offers little advantage over careful traditional step-sectioning of specimens, but may be of value if the histopathologist does not do routine meticulous step-sectioning.

Ischemic colitis with colonic necrosis is one of the uncommon gastrointestinal complications of systemic lupus erythematosus. In the few reported cases, only the abdominal part of the colon was involved with rectal sparing. This is the first report of gangrenous ischemic colitis isolated to the rectum, due to systemic lupus erythematosus vasculitis.

Recent reports have suggested that routine microscopic evaluation of anal ulcer tissue from AIDS patients is not the most accurate way to diagnose viral infection. This study was undertaken to determine if either viral culture (VC) or immunohistochemistry (IHC) can improve the diagnostic accuracy as compared with routine hematoxylin and eosin (H&E) staining. Specifically, we sought to identify inclusion bodies of cytomegalovirus (CMV) or herpes simplex virus (HSV) to assist in the diagnosis of CMV or HSV. All patients had clinical evidence of an anal ulcer or a nonhealing anal fissure. Duration of symptoms ranged from 1 week to 3 months with a mean of 6 weeks. All specimens were submitted for viral culture in addition to routine H&E staining; immunohistochemistry was also performed. Twenty-five paraffin-embedded anal ulcer biopsies from 23 male patients (age range 27-73; mean 37.4 years) with the diagnosis of AIDS or AIDS-related complex (ARC) were reviewed over a 4 year period (1988-1992). Routine H&E staining revealed 6 (22%) specimens with CMV inclusions. Four of these 6 reacted positively with IHC (67%) and one was positive on viral culture (17%). In the remaining 19 specimens that did not reveal infection with CMV (78%), IHC was positive in 2 patients (10%) and viral culture was positive in 1 patient (5%). Although HSV was not seen in any of the specimens on H&E staining, IHC was positive in one patient (3.5%) and viral culture reacted positively in 8 (29%) specimens. Thus IHC is a good confirmatory test for CMV inclusions and can be used to achieve a definitive diagnosis in equivocal cases.(ABSTRACT TRUNCATED AT 250 WORDS)

A study was undertaken to assess the incidence of inflammation and dysplasia in retained mucosa after double-stapled ileoanal reservoir (IAR) for mucosal ulcerative colitis (MUC). Between September 1988 and February 1992, 56 patients with MUC underwent an IAR. Forty-five patients had a double-stapled IAR (DS-IAR), seven patients had a transanal pursestring stapled IAR (PS-IAR), and four patients had a PS-IAR with mucosectomy. Distal donuts obtained from the stapled IAR were submitted for pathologic review in 55 patients. Nine patients had only small bowel, connective tissue, and/or muscle noted on review. Mucosa was qualified as squamous epithelium (SE), transitional epithelium (TE), or columnar epithelium (CE). All samples were examined for evidence of inflammation and dysplasia. Four patients had SE only, one patient had TE, and 18 had CE. In addition, three patients had SE and CE, seven patients had SE and TE, two patients had CE and TE, and nine patients had all three types. The distance from the dentate line to the anastomosis ranged from 0 to 2.5 cm (mean, 1 cm). In 19 patients (35 percent), the distal donut revealed MUC. Of these 19 patients, six had persistent MUC (43 percent) at the time of subsequent biopsy. An additional four patients had MUC evident on follow-up biopsy but not on distal donuts; two of these four patients had no mucosa in their distal donuts. Only one of the patients with evidence of MUC on donuts and/or biopsy experienced any symptoms referable to active MUC (1.8 percent). None of the specimens examined had any evidence of dysplasia. In 31 patients, no MUC was present in the initial donuts or follow-up biopsies. Although the double-stapled technique appears safe, periodic monitoring is suggested.

Background: We report a new plasminogen disorder detected in a 29-year-old man with a cerebellar infarct. To our knowledge, plasminogen disorders have not been previously linked with stroke., Summary of Report: Tests for well-recognized causes of stroke were negative. However, a screening hypercoagulation profile indicated low functional levels of plasminogen activity. Immunologic plasminogen (Laurell technique) was 64% of normal (normal level, 80-130%). The rate of plasmin generation induced by adding urokinase to plasma was also low. Plasminogen activator, free protease, and alpha 2-plasmin inhibitor levels were normal. Family studies detected a similar plasminogen abnormality in the patient's mother and 9-year-old son, both of whom are asymptomatic., Conclusions: Our patient shows a congenital, heterozygous, functionally abnormal plasminogen. Although the exact relationship to stroke is unclear, we suggest screening young patients with unexplained stroke for plasminogen defects using commercially available assay systems.

Of 40 patients with thrombotic thrombocytopenic purpura, 17 were treated with plasma exchange, 15 with exchange transfusions, and 6 with both types of therapy. One patient died before being treated and another patient was seen but not treated. Plasma exchange was performed daily for a mean of seven exchanges per patient. The replacement fluid during plasma exchange was fresh frozen plasma in all cases. The complete response rates for each type of treatment were as follows: 88% for plasma exchange (15 patients), 47% for exchange transfusions (7 patients), and 67% for exchange transfusions and plasma exchange (4 patients). Clinical and laboratory factors were examined for any statistically significant association with therapy response. Treatment with plasma exchange was statistically the initial factor most strongly associated with prognosis. Paresis, paresthesias, seizures, mental status change, and coma showed no association with response to treatment. Some of the laboratory factors that did not show significant association with treatment response were the initial creatinine, hemoglobin, platelet count, lactate dehydrogenase, and total bilirubin. This study supports the hypothesis that plasma exchange has significantly improved the prognosis of patients with thrombotic thrombocytopenic purpura. These patients should be treated aggressively regardless of the severity of their symptoms.

Cross-linked fibrin(ogen) dimers are known to be elevated in the plasma of subjects with occlusive vascular disease, and are thought to be fibrin dimers. Immunoelectrophoretic analyses of the dimers, however, indicate that (1) they are predominantly fibrinogen rather than fibrin dimers, and (2) they contain cross-linked A alpha-chains (A alpha-dyads) instead of the gamma-chain dyads that are rapidly formed by factor XIII during blood coagulation. Furthermore, the mobilities of the A alpha-dyads differ from the cross-linked alpha-chain products that accompany the gamma-chain cross-linking by factor XIII. Instead, the mobilities coincide with the distinct A alpha-dyads that are produced by tissue transglutaminase, an intracellular enzyme not normally present in plasma. The intimal fibrinogen deposits in atherosclerotic aortas also possess fibrinopeptide A and cross-linked A alpha-chains. Thus, both the plasma fibrinogen dimers and the intimal fibrinogen deposits appear to derive from the action of released tissue transglutaminase more so than factor XIII. It is proposed that, in the absence of other indications of cytolytic processes, the levels of A alpha-dyads in plasma reflect ongoing cellular injury accompanying atherogenesis. The extent to which gamma-dyads accompany the A alpha-dyads may signal progression of the disease to advanced stages in which ulcerations and occlusive lesions trigger thrombotic complications.

An ability of intravenous nitroglycerin to interfere with the anticoagulant properties of intravenous heparin would have profound clinical implications. To investigation nitroglycerin-heparin interactions, the following pilot study was performed. Patients (N = 18) admitted to the coronary care unit with a diagnosis of either acute myocardial infarction or unstable angina were divided into four treatment groups: (1) intravenous nitroglycerin and intravenous heparin; (2) intravenous nitroglycerin alone; (3) intravenous heparin alone; or (4) neither intravenous nitroglycerin nor intravenous heparin. Serial determinations of activated partial thromboplastin time (APTT), serum heparin concentration, antithrombin III (ATIII) antigen (ATA), and ATIII activity (ATC) were obtained over a 72-hour period. Overall, patients receiving intravenous nitroglycerin did not differ significantly from other patients in APTT, heparin dose, heparin concentration, ATA, ATC, or ATA/ATC ratio (ATR). However, patients receiving intravenous nitroglycerin at a rate exceeding 350 micrograms per minute had a lower APTT (p less than 0.05), lower ATC (p = 0.02), higher ATR (p = 0.004), and a larger heparin dose requirement than patients receiving lower infusion rates. ATR correlated directly (r = 0.91; p less than 0.05) and ATC inversely (r = -0.78; p less than 0.05) with the intravenous nitroglycerin dose. Serum heparin concentration did not correlate with the intravenous nitroglycerin dose. Intravenous nitroglycerin-induced heparin resistance occurs at a critical nitroglycerin dose. A nitroglycerin-induced qualitative ATIII abnormality may be the underlying mechanism.

Myeloperoxidase staining methods for classification of leukemias have traditionally employed benzidine dihydrochloride as the chromogen. Recent Occupational Safety and Health Administration regulations have classified benzidine as a carcinogen, which severely restricts its use in the clinical laboratory. Twenty-two specimens from normal control subjects and leukemia patients, previously classified by FAB criteria, were stained with benzidine and two alternate chromogens, diaminobenzidine and Hanker-Yates reagent (p-phenylenediamine and pyrocatechol). In a random, blind fashion, three experienced observers scored the stains from each case according to quality of smear, degree of peroxidase positivity, tinctorial distinction between nucleus and cytoplasm, and overall acceptability of the stain. All three observers rated the substitute chromogens as adequate for routine myeloperoxidase cytochemical staining. It is concluded that either of the methods studied would have clinical utility and can substitute for benzidine as a myeloperoxidase chromogen.

Fifty-eight patients with clinical inflammatory breast carcinoma and 15 patients with "occult" inflammatory cancer (dermal lymphatic carcinomatosis without clinical inflammation) are grouped and reviewed to determine whether diagnosis is pathologic or clinical. All cases represent a retrospective study of records from the Ellis Fischel State Cancer Hospital, Columbia, Missouri. Lesions of clinically apparent and occult inflammatory carcinoma demonstrate similar gross and microscopic growth patterns, histologic types, axillary involvement and early widespread metastases. Regardless of pathologic evidence of dermal lymphatic tumor, patients with clinical inflammation had rapid deterioration. Cases with only a pathological diagnosis were slightly less fulminant in progression. Either clinical or pathologic criteria justify use of the term "inflammatory breast carcinoma" to indicate short-term prognosis despite available treatment.

Electron-microscope study of chick tendon fibroblast revealed a constant ultrastructural finding of a microtubular-microfibrillar system and an intimate relationship which existed between the microtubular-microfibrillar system and secretory vacuoles. Additionally, the data from this study suggest a mechanism by which newly synthesized collagen molecules are transported and secreted into the extracellular space to be organized into mature collagen.

Recombinant human tissue-type plasminogen activator (rt-PA) was infused intraarterially at 0.1 mg/kg/h for 1-6 1/2 hours in 25 patients with lower extremity thromboembolic occlusions (13 thrombosed arteries, 12 thrombosed bypass grafts). Occlusion duration ranged from 1 hour to 21 days. Thrombolysis occurred in 23 of 25 patients (92%). Time to lysis varied from 1 to 6.5 hours, with an average time of 3.6 hours. Twenty of 23 patients (87%) in whom thrombolysis was successful benefited clinically from thrombolytic therapy. Twelve of 23 patients (52%) required secondary procedures to maintain arterial segment patency. In 15 of 25 patients (60%) fibrinogen levels were maintained above 50% of baseline values. No major complications directly attributable to rt-PA infusions occurred. rt-PA is a potent, relatively fibrin-specific thrombolytic agent that can achieve rapid thrombolysis while usually avoiding the profound systemic fibrinogenolysis associated with currently available thrombolytic agents.

A new assay for IgG bound to autologous platelets is described, in which IgG is dissociated from platelets washed at low pH, then measured by radioimmunoassay. Platelet-bound IgG was found to be elevated in thrombocytopenic patients with SLE and reduced in non-thrombocytopenic patients with this disease. There was a close inverse correlation of platelet-bound IgG and platelet count. Immune complexes did not interfere with the assay.

Twenty-two patients were selected from a group of 33 patients who underwent recombinant human tissue-type plasminogen activator (rt-PA) thrombolysis for thrombosed infrainguinal bypass grafts of the lower extremity and were compared with 38 matched patients who had undergone surgical thrombectomy during the same period. The proportion of persons with diabetes mellitus, smokers, and types of bypass grafts was similar in both groups. More patients in the rt-PA-treated group had hypertension (p = 0.01). To evaluate the different lengths of follow-up, Kaplan-Meier survival analysis was used with a log-rank test to compare the proportion of persons with patent grafts in the two treatment groups. At 30 days, 86% of the rt-PA-treated grafts were still patent compared with 42% of the surgically treated grafts (p = 0.001). When risk factors on the Kaplan-Meier curves were compared, there was no statistical difference with regard to graft patency among the groups. According to simultaneous Cox regression analysis, no risk factor was significantly associated with graft patency. When amputation was evaluated between treatment groups simultaneously with other risk factors in a logistic regression analysis, smoking and age of the graft were marginally significant (p = 0.07), whereas all other factors were clearly not significant. In 91% of the rt-PA-treated patients, a secondary surgical procedure was required to maintain patency of the graft segment. Eighty-nine percent of the surgically treated patients required similar graft revisions. Two patients in the surgical group and one patient in the rt-PA-treated group had major complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Factor VIII assays are the most common specific coagulation factor assay performed in the United States. Interlaboratory proficiency studies have documented persistent problems with variation in results between laboratories. The Coagulation Resource Committee of the College of American Pathologists conducted a workshop to analyze variables that may affect performance of the one-stage factor assay. The results indicate that accuracy of the assay can be improved by uniform standardization of reference plasma samples and that reproducibility can be enhanced through appropriate choice of reagents and instruments. Optimizing performance of this assay should lead to more reproducible interlaboratory results.

Thirty-three patients with thrombosed peripheral arteries and bypass grafts, as confirmed by angiography, were treated with recombinant human tissue-type plasminogen activator (rt-PA). Twenty-six patients were treated with a dose of 0.1 mg/kg/hr and seven patients with 0.05 mg/kg/hr. Thrombus lysis and clinical improvement occurred in 22 of 26 (85%) patients in the 0.1 mg/kg/hr group. In seven of seven (100%) patients in the 0.05 mg/kg/hr group angiographic as well as clinical improvement were observed. Fifteen of the 33 patients required anticoagulation to maintain patency. Sixteen required secondary procedures to maintain patency. One (3%) patient required a blood transfusion for a hematoma at the catheter entry site. Three other patients developed small hematomas that were controlled without transfusion or intervention. Sixty-one percent of patients treated with the 0.01 mg/kg/hr dose and 86% of patients treated with the 0.05 mg/kg/hr dose maintained fibrinogen levels greater than 50% of their initial values. Infusion durations ranged from 1 to 6 hr (mean 3.9 hr). rt-PA appears to be a potent and selective thrombolytic agent that rapidly and safely lyses thrombi in peripheral arteries and occluded bypass grafts.

Fluorescein is a reliable indicator of mucosal viability in dogs. This fact is probably applicable to humans. The Doppler device was not a reliable predictor of intestinal nonviability, and in the instance of mesenteric venous occlusion, with ischemic intestine, it was totally inaccurate in assessing intestinal viability. Short segments of intestine failing to take up fluorescein stain will retain viability, owing to the lesser nutrient requirements of resting smooth muscle. However, segments should not be used for anastomoses, since the mucosa will, to some degree be ischemic.

A method was development for the isolation of prostacyclin (PGI2) from whole blood in a fraction suitable for high pressure liquid chromatography (HPLC) separation of PGI2 and 6-keto-prostaglandin F1 alpha (6-K-PGF1 alpha). Prostacyclin was stabilized in whole blood by rapidly raising the pH to 10 with Na2CO3 and cooling the samples to 0 degree C. Under these conditions, 2.9% hydrolysis was observed after 20 min. Reverse phase extraction columns were used to directly extract both PGI2 and 6-K-PGF1 alpha from the alkaline plasma with recoveries of greater than 95% using an acetonitrile/2mM Na2B4O7, pH 10, 40/60 elution solvent mixture. An additional 1.7% hydrolysis was found during the column extraction procedure. Final separation of PGI2 and 6-K-PGF1 alpha was performed with HPLC using an alkaline solvent system. This method is capable of rapidly and efficiently extracting and separating PGI2 and 6-K-PGF1 alpha from whole blood or plasma. It introduces less than 5% hydrolysis of PGI2, thus providing a means of applying highly sensitive 6-K-PGF1 alpha assays to the determination of PGI2 levels in physiological samples.

Unequivocal establishment of the correct diploid chromosome number in 1956 started the modern era of human cytogenetics. The next impetus came when the peripheral blood leukocyte culture technique for the chromosome preparation was described in 1960. Discovery of special staining procedures - banding techniques - in early seventies not only saved it from early senescence but played decisive roles in broadening the horizons of modern human cytogenetics.

The platelet membrane contains sulfhydryl groups which are essential for normal platelet function. Reduced glutathione (GSH) and other thiols such as cysteine and 6-mercaptopurine were found to inhibit human platelet aggregation induced by adenosine diphosphate (ADP), collagen and arachidonic acid. The inhibition of ADP-induced aggregation by GSH (IC50 = 0.61 +/- 0.05 mM) was greater than that by cysteine (IC50 = 13 +/- 1 mM) or 6-mercaptopurine (IC50 = 5.4 +/- 0.2 mM). Two other thiols, dithiothreitol and beta-mercaptoethanol were found to cause platelet aggregation instead of inhibition. The interaction of GSH with the ADP receptor was noncompetitive in nature.

The stability of prostacyclin (PGI2) in whole blood and plasma was studied in vitro by measuring the disappearance rate of labeled prostacyclin during a 37 degrees C incubation. Prostacyclin was assayed using a quantitative chromatographic method. The half-life of PGI2 was 6.3 +/- 0.8 minutes (mean +/- s.d., n = 6) in citrated human whole blood, significantly shorter (p less than 0.001) than the 10.7 +/- 2.3 minute half-life in citrated human plasma (n = 7). Prior freezing and thawing of plasma did not affect the rate of PGI2 hydrolysis. These values, including the prolonged half-life in plasma, were similar in the blood (5.4 +/- 1.8 min, n = 7) and plasma (9.0 +/- 1.9 min, n = 14) of diabetic patients. In plasma samples from patients with thrombotic thrombocytopenic purpura, the half-life of prostacyclin (4.9 +/- 1.0 min, n = 4) was significantly shortened (p less than 0.001) compared to that in plasma from normal volunteers. The stability of prostacyclin in rabbit blood and plasma was also quantified. The PGI2 half-life in citrated rabbit plasma (10.8 +/- 1.1 min, n = 3) was similar to that in citrated human plasma from control subjects. In contrast to the findings in human blood, the half-life of PGI2 in citrated rabbit whole blood (11.7 +/- 3.3 min, n = 4) was not different from the rabbit plasma value. Substitution of EDTA for citrate did not affect the half-life in rabbit blood or plasma.

Prostacyclin (PGI2) has been used extensively in human clinical trials and animal studies, but because of its instability, knowledge of its pharmacokinetics has progressed slowly. We assayed plasma PGI2 concentrations with a quantitative chromatographic method following bolus intravenous injection and during continuous infusion in rabbits. Blood pressure response was correlated with plasma PGI2 concentrations and compared with the concentrations necessary to inhibit platelet aggregation in vitro. A two-compartment model was used to analyze the elimination kinetics for PGI2 after a single injection. The half-life of the terminal elimination phase was 2.7 minutes. The calculated systemic clearance and whole body volume of distribution were 93 ml/kg/min and 357 ml/kg, respectively. During continuous infusion, steady-state plasma concentrations were reached within 15 minutes and increased linearly with increasing infusion rate from 4.2 to 604 ng/kg/min, which resulted in PGI2 concentrations of 0.06 +/- 0.01 to 7.6 +/- 2.1 ng/ml, respectively. At steady-state plasma concentrations of PGI2 greater than 0.1 ng/ml, the mean arterial blood pressure decreased in a concentration-dependent manner, reaching a decrease of 45 mm Hg when the plasma concentration was 7.6 ng/ml. Prostacyclin caused a concentration-dependent inhibition of adenosine diphosphate-induced platelet aggregation in vitro with 10% inhibition at 0.4 ng/ml. These results indicate that in the rabbit the level of PGI2 at which the onset of hypotension occurs coincides with the inhibition of platelet aggregation.

Three cases of a newly recognized "microgranular" variant of acute promyelocytic leukemia (FAB M3) are described. This poor-prognosis variant is easily confused with myelomonocytic (M4) or monocytic (M5) leukemia, but is associated with disseminated intravascular coagulation as is "hypergranular" M3. Such patients may be inappropriately treated unless the promyelocytic nature of the leukemia is recognized.

We describe briefly and comment upon the salient strengths and limitations of the major published theories that purport to explain the mechanism of contrecoup cerebrocortical contusions. Through the application of mechanical principles, we then present a modification, clarification, and expansion of selected aspects of several theories. Our final formulation emphasizes the injurious potential of nonuniform compressive stress and the relationship between brain lag and rotationally induced injury. The resulting theory remains faithful to the laws of physics while explaining the location and distribution of cerebrocortical contusions opposite the site of a moving head impact.

Since infective endocarditis may affect individuals without pre-existing valvar heart disease, and Staphylococcus aureus is the organism most commonly involved, the binding characteristics of S aureus to several components of normal vascular endothelium and subendothelium were studied. S aureus adhered specifically to endothelial monolayers (6.08(1.10)%; p less than 0.005), fibronectin (5.43(0.81)%; p less than 0.001), fibrinogen (7.13(1.43)%; p less than 0.001), and acid soluble calf skin collagen (2.38(0.90)%; p less than 0.001). S aureus also adhered specifically to Von Willebrand factor (1.62(0.28)%, p less than 0.001). Protein A containing (Cowan I) and deficient (Wood) strains of S aureus adhered similarly to all surfaces and substrates (NS). Escherichia coli adhered poorly. Immunofluorescence microscopy of preconfluent endothelial cells identified an extensive pericellular fibronectin network at regions of cell to cell contact. Light microscopy showed S aureus binding solely within these regions. Therefore, the ability of S aureus to infect valvar endothelium may be dependent on the presence of a fibronectin receptor. The existence of specific receptor for S aureus on the endothelial cell surface itself remains undetermined.

The potential for specific immunophenotypic characterization of the acute leukemias has been enhanced greatly by the development of monoclonal antibodies. Currently, this immunologic data is obtained most commonly by flow cytometric analysis or cellular cytotoxicity assays. The former is an expensive technic that lacks morphologic evaluation unless cell sorting is performed. The latter precludes morphologic assessment by the nature of the assay. The authors have developed an immunostaining procedure utilizing cytospin preparations and immunoperoxidase methods that are relatively inexpensive and allow simultaneous assessment of the immunologic markers and cellular morphology. Although a comparison of flow cytometry and immunocytology revealed quantitative differences for individual cell surface markers, the "qualitative" immunologic phenotype of the leukemic population was virtually identical by the two technics.

The relationship of the reduced glutathione (GSH) content in unstimulated platelets and their capacity to synthesize thromboxane A2 (TXA2), measured by radioimmunoassay of TXB2, was investigated in diabetic and matched control subjects. The GSH content in platelets from diabetic subjects (6.52 +/- 0.73 microgram/10(9) platelets, mean +/- SD) was significantly (P less than 0.001) lower than in platelets from control subjects (10.10 +/- 1.58 microgram/10(9) platelets). When platelet-rich plasma (PRP) was stimulated with 1.65 mM arachidonic acid, significantly (P less than 0.001) more TXB2 was formed in PRP from diabetic subjects (344 +/- 87 ng/2.5 X 10(8) platelets) than in PRP from control subjects (132 +/- 35 ng/2.5 X 10(8) platelets). Furthermore, the plasma level of TXB2 was increased in diabetic subjects (522 +/- 117 pg/ml) in comparison with control subjects (187 +/- 63 pg/ml). An inverse correlation (r = 0.98) was observed between the GSH content in unstimulated platelets and their capacity to synthesize TXA2 when stimulated with 1.65 mM arachidonic acid. These data suggest that platelet GSH may have an important regulatory effect on platelet TXA2 synthesis and that increased TXA2 synthesis by platelets from diabetic subjects may be the result of low intracellular GSH levels.

Prospective characterization of pharmacodynamics of tissue-type plasminogen activator (t-PA) is needed for diverse clinical applications. Accordingly, we used physiologically based, computer simulation of participating biochemical reactions in response to concentrations of circulating t-PA seen with infusions of 1 to 7 hr duration in 45 patients. Predicted values were compared with those from a "training set" obtained in six patients given t-PA for coronary thrombosis and six receiving therapy for peripheral arterial occlusion. Subsequently, results of simulation were compared prospectively with observations from a "test set" of 33 consecutive patients given low doses of t-PA for as long as 7 hr or higher doses for 1 to 2 hr and with data from 101 patients given t-PA in the European Cooperative Trial. Fits between observed and predicted values were close. Based on observations in the training set, the alpha 2-macroglobulin reaction with circulating plasmin and ongoing synthesis of plasminogen were incorporated in the simulations. Fibrinogenolysis in vitro was documented despite supplementation of samples with aprotinin, particularly when concentrations of t-PA were high. This phenomenon can lead to overestimation of fibrinogen depletion and was found to be obviated by the use of PPACK, a novel serine protease inhibitor. Results indicate that the simulation approach developed permits economic, prospective evaluation of regimens of t-PA suitable for diverse conditions and delineation of the impact of individual constituents and reactions on pharmacodynamics of t-PA and on the risk of induction of a systemic lytic state.

The time-dependent relationship between the levels of the reduced form of glutathione (GSH) and thromboxane A2 (TXA2) synthesis, as measured by the accumulation of TXB2, in platelets from human diabetic and control subjects was investigated during aggregation. In platelets from control subjects, the GSH level decreased to 21% of the initial level within 30 sec in response to arachidonic acid (1.65 mM) and rapidly recovered to 91% by 1 min. In platelets from diabetic subjects, the GSH level decreased to 3% of the initial level within 30 sec and recovered to only 41% by 1 min. During collagen (20 ug/ml) aggregation, platelets from control subjects had a 15 sec lag phase which was followed by a decrease in the GSH level to 21% of the initial level within 1 min and a recovery to 74% by 2 min. Platelets from diabetic subjects in response to collagen showed no lag phase and decreased to 10% of the initial level within 1 min which was followed by a recovery to 34% by 2 min. In all aggregations, the initial GSH level was significantly (p less than .001) lower in platelets from diabetic subjects and remained significantly (p less than .01) lower than GSH in platelets from control subjects throughout the aggregation. The amount of TXB2 formed by platelets from control subjects reached a maximum in response to arachidonic acid and collagen by 1 min and 2 min, respectively, whereas, the TXB2 continued to increase up to 4 min when platelets from diabetic subjects were aggregated. These data indicate that TXA2 synthesis occurs during the decrease in GSH and ceases when the GSH level recovers. The continued synthesis of TXA2 by platelets from diabetic subjects coincides with the gradual recovery of the GSH level.

The purpose of this investigation was to study the effects of a selective thromboxane A2 (TXA2) synthetase inhibitor (TSI) upon the evolution of cerebral infarction in the cat. Adult cats, lightly anesthetized with nitrous oxide, underwent right middle cerebral artery (MCA) occlusion for 4 hours followed by a 2-hour period of reperfusion before sacrifice. Ten cats received 3 mg/kg TSI intravenously immediately before, and 10 cats received 3 mg/kg TSI intravenously immediately after MCA occlusion. Ten cats were used as controls receiving no treatment. The bleeding time was determined at baseline and at the end of each experiment. Electroencephalographic (EEG) recordings were obtained before and after MCA clipping and MCA release, and at hourly intervals thereafter. Regional cerebral blood flow (rCBF) was measured using the xenon-133 (133Xe) clearance technique before and after MCA occlusion, after MCA reopening, and before terminating each experiment. Thirty minutes before each cat was sacrificed, Evans blue dye and sodium fluorescein were given intravenously. The animals were then perfused with colloidal carbon and the brains removed and evaluated for midline shift. Evans blue dye and sodium fluorescein extravasation, carbon staining, and infarct size. The bleeding time, arterial blood pressure, rCBF changes, brain swelling, and vital dye extravasation were not statistically different between the three treatment groups. The EEG changes, carbon staining, and infarct size differences between the three groups also failed to reach statistical significance, but there was a suggestion that these parameters were adversely affected in the cats pretreated with TSI. Ten additional cats undergoing MCA occlusion and reperfusion were used for pharmacological studies. Five of them received 3 mg/kg TSI intravenously immediately after MCA occlusion, and serial drug and thromboxane B2 (TXB2) levels (a stable metabolite of TXA2) were determined. Another five cats were not treated and serial TXB2 levels were obtained. Production of TXA2 was inhibited by 95% in cats receiving TSI. In conclusion, thromboxane synthetase inhibition failed to modify favorably the evolution of cerebral infarction. When TSI was given before MCA occlusion, cerebral infarction tended to be more extensive.

The VA Hospital in Columbia, MO, and the University of Missouri Medical Center conduct the largest shared laboratory service in the VA hospital system. Sharing has enabled these institutions to eliminate unnecessary duplication of resources, develop new laboratory capabilities in subspecialties, handle additional routine procedures, better use the expertise of senior staff pathologists, develop uniform standards, enhance quality assessment, and expand training programs.