Pancreatic undifferentiated carcinoma with osteoclast‐like giant cells is genetically similar to,but clinically distinct from,conventional ductal adenocarcinoma

Undifferentiated carcinoma of the pancreas with osteoclast‐like giant cells (UCOGC) is currently considered a morphologically and clinically distinct variant of pancreatic ductal adenocarcinoma (PDAC). In this study, we report clinical and pathological features of a series of 22 UCOGCs, including the whole exome sequencing of eight UCOGCs. We observed that 60% of the UCOGCs contained a well‐defined epithelial component and that patients with pure UCOGC had a significantly better prognosis than did those with an UCOGC with an associated epithelial neoplasm. The genetic alterations in UCOGC are strikingly similar to those known to drive conventional PDAC, including activating mutations in the oncogene KRAS and inactivating mutations in the tumor suppressor genes CDKN2A, TP53, and SMAD4. These results further support the classification of UCOGC as a PDAC variant and suggest that somatic mutations are not the determinants of the unique phenotype of UCOGC. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Metabolism of leukotrienes by adult and fetal human lungs

The metabolism of leukotriene (LT) A4, B4, C4, D4, and E4 was studied using both bioassay and reversed phase high performance liquid chromatography (RP-HPLC) methods. The incubation of 20,000 g supernatants of homogenates of human adult lung with LTA4 and LTC4 for various periods of time produced substances of higher biologic activity than the controls (without incubation) when measured on strips of guinea pig lung parenchyma and ileum. RP-HPLC analyses of the incubation media revealed the formation of LTB4, LTC4, LTD4, and LTE4 from LTA4 and the formation of LTD4 and LTE4 from LTC4. LTD4 was converted to LTE4 whereas LTB4 and LTE4 were not catabolized to an appreciable extent during a 2-h incubation period. Supernatants (20,000 g) of human fetal lung homogenates also contain the enzymatic activities to transform LTC4 into LTD4 and LTE4; however, LTA4 was mainly converted to LTB4 and to products of the nonenzymatic hydrolysis of LTA4 such as the delta 6-trans-LTB4, delta 6 -trans-12-epi-LTB4 and the 5,6-dihyroxyeicosatetraenoic acids; much smaller quantities of the peptidoleukotrienes were formed than in adult lung homogenates.     

High-molecular-weight kininogen is exclusively membrane bound on endothelial cells to influence activation of vascular endothelium

An important biologic function of high-molecular-weight kininogen (HK) is to deliver bradykinin (BK) to its cellular receptors. Internalization and degradation of HK may provide a mechanism by which endothelial cells modulate the production of BK and control its activities. Therefore, we investigated the binding and subsequent distribution of biotinylated-HK (biotin-HK) associated with human umbilical vein endothelial cells (HUVEC). HUVEC bound 3 to 4 times more HK and with greater avidity at 1 to 3 hours at 37 degrees C than at 4 degrees C (Bmax = 1.0 +/- 0.02 x 10(7) molecules/cell, kd = 7 +/- 3 nmol/L v Bmax = 2.6 +/- 0.2 x 10(6) molecules/cell, kd = 46 +/- 8 nmol/L). However, there was no evidence that the difference was caused by internalization of HK at the higher temperature. First, the same amount of biotin-HK was associated with nonpermeabilized and permeabilized HUVEC using buffers containing 20 to 50 mumol/L zinc ion in the absence or presence of 2 mmol/L calcium ion. Second, binding of biotin-HK to HUVEC was approximately 92% reversible at 1 hour when the cells were maintained at both 37 degrees C and 4 degrees C. Third, neither chloroquine nor primaquine altered the amount of biotin-HK bound to HUVEC. Fourth, biotin-HK bound to HUVEC was almost completely removed by pronase. Fifth, the nonpermeable dye, crystal violet, almost completely quenched the fluorescence signal emitted by HUVEC-associated fluorescein isothiocyanate (FITC) HK. Finally, the localization of HUVEC-bound FITC-HK was restricted to the membrane as shown by laser scanning confocal microscopy. The expression of HK binding sites had an absolute requirement for metabolic energy, but was not dependent on new protein synthesis. Membrane-bound HK contributed to the anticoagulant nature of endothelial cells by blocking human alpha-thrombin binding and its resultant induction of prostacyclin formation. These studies indicate that HK is not internalized by HUVEC, but remains primarily on cell surfaces to be accessible for BK liberation and to modulate the binding and actions of alpha-thrombin.     

Role of light chain variable region in myeloma with light chain deposition disease: evidence from an experimental model

Light chain deposition disease (LCDD) results from a propensity of some human monoclonal L chains to form tissue deposits. We designed an experimental model for in vivo expression of human kappa L chain sequences in mice and compared a somatically mutated LCDD chain with a closely related control kappa chain, both encoded by the unique V kappa IV gene. Mice secreting the LCDD chain but not those producing the control chain showed deposits with a distribution similar to that observed in patients. These data show that discrete changes in V region sequences can play a major role in tissue deposition of human L chains.     

Comparative hemodynamics and cardiovascular effects of endotoxin and platelet-activating factor in rat

We have compared the cardiovascular effect of endotoxin with platelet-activating factor (PAF) in rats. Endotoxin injected into perfusate of isolated rat heart did not induce significant changes in heart function, whereas PAF induced elevation of coronary perfusion pressure (CPP), decrease in ventricular pressure (VP), decrease in coronary flow (CF), but no significant changes in heart rate (HR). Neither endotoxin nor PAF caused contraction or relaxation of isolated rat arteries. However, endotoxin in the presence of macrophages caused contractions of rat aortic strips. These contractions were potentiated when platelets were present in the macrophage preparation. PAF in the presence of platelets caused profound contraction of the aortic strips, and this action of PAF was entirely blocked by either PAF antagonists or thromboxane antagonists. Injection of endotoxin into rats (i.v.) caused a decrease in blood pressure (BP) without significantly affecting the HR. At higher concentrations (greater than or equal to 10 mg/kg), endotoxin caused ventricular tachycardia (VT) associated with ventricular fibrillation (VF). PAF in vivo caused a rapid and sustained decrease in BP, with an ED50 of 3 micrograms/kg. PAF antagonists significantly prevented overall mortality induced by PAF and short-term endotoxin-induced mortality, but not the long-term (week) mortality. Endotoxin (10 mg/kg) injected into rats caused the release of PAF into the circulation, reaching a maximum after 2-5 min. Tritiated PAF injected into rats i.v. was metabolized over 60 min into lyso-PAF (approximately 30%), acyl-PAF (approximately 10%), and some degraded products (approximately 10%), and the remainder was found in the form of PAF. The results of the present study suggest that PAF may play a significant role in the pathogenesis of endotoxin shock. The action of PAF requires the participation of cells such as platelets, macrophages, neutrophils, and monocytes and involvement of arachidonic acid metabolites.     

Advancement of multiple myeloma from diagnosis through plateau phase to progression does not involve a new B-cell clone: evidence from the Ig heavy chain gene

The Ig heavy chain (IgH) gene was used as a marker to investigate clonal succession and the origin of the neoplastic cell in multiple myeloma. The polymerase chain reaction (PCR) was used to amplify a section of the rearranged IgH gene at diagnosis and at progression in 21 patients who had exhibited a plateau phase. A monoclonal PCR product was seen for 16 of the patients and the product present at progression was of the same molecular weight as that at diagnosis. This finding suggests that the IgH rearrangement present at diagnosis and progression was the same. This was confirmed by sequencing the IgH gene in 10 patients. The IgH genes were found to be hypermutated at diagnosis, but no further hypermutation occurred during the course of the disease. The results provide evidence that the neoplastic cell in myeloma may originate as a memory B cell, plasmablast, or plasma cell, and suggest that progression beyond the plateau phase is not caused by clonal succession.