Megakaryocytes in pleural and peritoneal fluids: prevalence, significance, morphology, and cytohistological correlation.

Over a period of 22 years, 4844 pleural and peritoneal fluids from 3279 patients were examined cytologically. Megakaryocytes were found in the fluids from five patients. The clinical diagnoses in the five patients were agnogenic myeloid metaplasia, chronic myeloid leukaemia, and lymphocytic lymphoma. All of these patients had persistent serous effusions. Megakaryocytes in serous fluids occurred in three forms: (1) a large type with abundant cytoplasm and multilobed nuclei, (2) a smaller type with a high nucleocytoplasmic ratio and unlobed nuclei, and (3) anucleate cytoplasmic masses. Foci of agnogenic myeloid metaplasia found on the serous surfaces at necropsy of two patients contained megakaryocytes similar to those in the corresponding effusions. The clinical course of our patients confirmed that the presence of megakaryocytes in serous fluids signifies an advanced haematopoietic malignancy.     

Enhanced expression of stem cell antigen-1 (Ly-6A/E) in lymphocytes from lupus prone mice correlates with disease severity

B6.Sle1 mice, congenic for the NZM2410-derived lupus susceptibility locus, Sle1 on chromosome 1 exhibit many of the features seen in human lupus including activated lymphocytes and high titers of antinuclear autoantibodies. Among the different surface molecules that were aberrantly expressed on the B6.Sle1 lymphocytes was Ly-6A/E. Splenic B- and T-lymphocytes but not myeloid cells from B6.Sle1 mice exhibited enhanced levels of Ly-6A/E compared to B6 controls. In particular, MZ B cells, GC B cells and B-cell blasts expressed the highest levels of Ly-6A/E in both strains, with the levels being even higher on B6.Sle1 derived cells. Following stimulation with LPS or anti-IgM, there was a profound up-regulation in Ly-6A/E, particularly on MZ B cells and B-cell blasts. CD4 and CD8 T cells also up-regulated Ly-6A/E after stimulation with anti-CD3 and anti-CD28. These studies were extended to additional autoimmune strains including B6.Sle3, B6.Sle1.lpr and BXSB. Importantly, Ly-6A/E levels on lymphocytes were commensurate with the degree of disease exhibited by these lupus strains. Finally, it appears that increased interferon levels, in addition to antigen receptor stimulation, may also be a factor accounting for elevated Ly-6A/E in lupus. Given these observations it is important to elucidate the functional role of Ly-6A/E in lupus in future studies.     

Mantle Cell Lymphomas Lack Expression of p27kip1, a Cyclin-Dependent Kinase Inhibitor

p27^Kip1 is a cyclin-dependent kinase inhibitor that regulates the decision to enter S phase or withdraw from the cell cycle. In resting cells, the level of p27^Kip1 provides an inhibitory threshold above which G1 cyclin D/E/cyclin-dependent kinases accumulate before activation; however, in cycling cells, p27^Kip1 protein is sequestered by high levels of active cyclin D/cyclin-dependent kinase 4 complexes. As a group, the cyclin-dependent kinase inhibitors have been proposed to act as tumor suppressor genes, and several members have been implicated in the pathogenesis of a variety of human cancers. We examined p27^Kip1 expression in 116 non-Hodgkin’s lymphomas including 50 cases of MCL (40 typical and 10 blastic variants), 21 follicular lymphomas, 20 diffuse large B-cell lymphomas, 16 chronic lymphocytic leukemias, 8 marginal zone B-cell lymphomas, and 1 splenic marginal zone lymphoma, and correlated its expression with that of the proliferation marker Ki67 (MiB1) and with p53. p27^Kip1gene structure was analyzed by Southern blot in the group of MCLs. In all cases of non-Hodgkin’s lymphoma other than MCL, p27^Kip1 expression was inversely related to the proliferation index as measured by Ki67. In contrast, in typical MCL, p27^Kip1 expression was negative in 35 of 40 (88%) cases, irrespective of the proliferative rate (median 15%; range 2 to 90%). Paradoxically, in the blastic variant of MCL, 8 of 10 (80%) cases showed expression of p27^Kip1, despite a high proliferation rate (median 60%; range 32 to 100%). However, the staining in most of the cases was less intense than in the reactive T lymphocytes. Deletions of p27^Kip1gene were not found in any of the 25 cases examined. p53 expression was found in 15 of 50 cases of MCL: 7 of 10 (70%) in the blastic variant and 8 of 40 (20%) in the typical MCL (70% vs. 20%, P < 0.0045). These results demonstrate that MCLs, in contrast to other non-Hodgkin’s lymphomas and normal lymphoid tissue, fail to correlate p27^Kip1 expression with the proliferation rate. This peculiar uncoupling of p27^Kip1 protein expression from the proliferation rate may be related to the high levels of cyclin D1 expressed in MCL and is likely to have profound effects on cell cycle regulation and contribute to the pathogenesis of MCL.     

Role of Periductal and Ductular Epithelial Cells of the Adult Rat Pancreas in Pancreatic Hepatocyte Lineage: A Change in the Differentiation Commitment

Development of pancreatic hepatocytes in adult rats maintained on copper deficient diet containing 0.6% trien (CuDT) has been reported recently. To elucidate the histogenesis of hepatocytes a sequential study was undertaken using morphologic, histochemical, immunochemical, in situ hybridization, and Northern blot analysis. Male F-344 rats weighing 80 to 90 g were fed CuDT for 8 weeks and returned to normal rat chow. Beginning from 4 weeks of copper depletion, there was a progressive loss of acinar cells and by 8 weeks more than 90% of the acinar tissue was lost. During this period, there was an increase in the number of adipocytes in the interstitium, and in the number of interstitial and ductular cells. Morphologic observations were confirmed by immunoblot and Northern blot analysis, in which the amount of pancreatic proteins and their mRNAs decreased between 5 and 8 weeks. During this period, a progressive increase in the level of albumin mRNA was observed. In situ hybridization, performed at 7 weeks of copper deficiency, showed localization of albumin mRNA over interstitial and ductular cells. Pancreatic hepatocytes were identified immediately after the rats were returned to a normal diet and gradually increased in number. The hepatocytes occupied almost 60% of the pancreatic volume by 8 weeks. During the early recovery phase, hepatocytes were identified in ductules as well as in the interstitium. Based on these studies, it is concluded that both the ductular cells and interstitial cells, which resemble oval cells of liver, are capable of transforming into pancreatic hepatocytes and these cells may be considered stem-cell equivalent.     

Heart-focused anxiety,illness beliefs,and behavioral impairment: Comparing healthy heart-anxious patients with cardiac and surgical inpatients

Psychological features and complaints of persons presenting to medical settings with heart-focused anxiety and noncardiac chest pain are poorly understood. Comparing 20 healthy heart-anxious patients to cardiac and surgical inpatients and nonpatient controls, we found that healthy heart-anxious patients (a) were as afraid of chest pain and heart palpitations as inpatients with heart disease, (b) were as incapacitated by symptoms and using medical services as much as both inpatient groups; and (c) reported higher levels of cardiac disease conviction, heart awareness, and behaviors designed to protect their heart than surgical patients and nonpatients. Compared to all other groups, healthy heart-anxious patients reported more panic and other anxiety disorders, hypochondriacal beliefs, physical symptoms, obsessive-compulsive concerns, and negative affect. Following a hyperventilation test, heart-anxious patients also indicated more distressing symptoms and thoughts, and felt less safe and in control than surgical patients and nonpatients. Results support efforts for a timely recognition, diagnosis, and behavioral treatment of persons with heart-focused anxiety.     

Dysregulated production of interleukin-10 (IL-10) and IL-12 by peripheral blood lymphocytes from human immunodeficiency virus-infected individuals is associated with altered proliferative responses to recall antigens.

The loss of immune function following infection with human immunodeficiency virus (HIV) may result from altered production of immunoregulatory cytokines such as interleukin-10 (IL-10) and IL-12. In this study, we analyzed IL-10 and IL-12 production by mitogen-stimulated peripheral blood mononuclear cells (PBMC) from HIV+ individuals and correlated their levels with proliferative responses to the recall antigens HIV p25 and influenza virus. We report two distinct groups of HIV+ patients. One group produced small amounts of IL-10, had PBMC that proliferated in response to recall antigens, and demonstrated enhanced recall antigen-induced proliferation upon addition of anti-IL-10 antibodies and/or IL-12. Conversely, the second group produced high levels of IL-10, had PBMC that failed to proliferate to recall antigens, and did not demonstrate enhanced proliferation upon addition of anti-IL-10 antibodies and/or IL-12. Mitogen-stimulated PBMC from both groups produced significantly lower levels of IL-12 than did those from HIV- controls. Analysis of the source of the IL-10-producing cell subset in PBMC demonstrated that in HIV+ individuals, IL-10 is produced by monocytes, while in HIV- controls, it is produced by both T cells and monocytes. Taken together, our results suggest that monocytes from HIV+ individuals secrete decreased amounts of IL-12, a Th1-type cytokine, which may lead to the development of Th2-type responses characterized by high IL-10 secretion and immune dysfunction.     

Oestrogen and progesterone do not regulate the expression of retinoic acid receptors and retinoid 'X' receptors in human endometrial stromal cells in vitro

Elucidation of the gene structure for retinoic acid receptor-(RAR-) has suggested a potential role for oestrogen in regulatingthe expression of RAR-. We have previously shown that all threeRAR types are expressed in human endometrial stromal cells invitro and that RAR- expression is induced in response to retinoicacid. The aim of this study was to ask whether oestradiol andprogesterone could play a part in regulating the expressionof RARs in human endometrial stromal cells and to establishthe patterns of expression of a related group of nuclear retinoidreceptors, retinoid ‘X’ receptors (RXRs) and theirpotential for regulation by steroid hormones. The RAR expressionpatterns of endometrial stromal cells, grown in steroid-freemedium, did not change in response to the presence of steroidhormones. Furthermore, the retinoic acid-mediated inductionof RAR- was not affected by oestradiol or progesterone, andwas dependent on the continued presence of retinoic acid. Ofthe three RXR types, only RXR- was detectably expressed in stromalcells in vitro and the expression of RXR- did not change inresponse to steroid hormones or retinoic acid. These data indicatethat oestradiol and progesterone are not important in the regulationof RAR and RXR expression in human endometrial stromal cells.     

Cell death by apoptosis in acute leukaemia

We have previously demonstrated that when freshly isolated childhood T-cell acute lymphoblastic leukaemia cells are incubated in growth medium after isolation from blood, chromatin is rapidly cleaved into nucleosomal sized fragments that are multiples of 200 bp. The fragmentation is similar to that observed in other types of cells undergoing apoptosis or programmed cell death. In this study we describe a more comprehensive approach to the study of DNA fragmentation in leukaemia. Fragmentation was observed in freshly isolated cells from patients with T-cell acute lymphoblastic leukaemia and in one with common acute lymphoblastic leukaemia. Frozen samples of T-cell acute lymphoblastic leukaemia, common acute lymphoblastic leukaemia, and acute myeloid leukaemia cells also showed fragmentation of DNA. However, no fragmentation was evident in normal leukocytes treated under the same conditions. Ultrastructural studies on the isolated leukaemia cells demonstrate that the chromatin cleavage observed biochemically is associated with morphological changes characteristic of apoptosis.     

Increased levels of inflammatory mediators in children and adults infected with Vibrio cholerae O1 and O139

Investigations were carried out to study the production of factors associated with the innate immune response in the systemic and mucosal compartments in adults and children infected with Vibrio cholerae O1 and V. cholerae O139. The levels of nonspecific mediators of the innate defense system, i.e., prostaglandin E(2) (PGE(2)), leukotriene B(4) (LTB(4)), and lactoferrin (Lf), as well as myeloperoxidase (MPO), were elevated at the acute stage of the disease in stools obtained from both O1- and O139-infected adults and children. In the systemic compartment, the levels of Lf were increased after onset of disease, which in children remained elevated up to convalescence compared to the healthy controls. Increased concentrations of C-reactive protein were seen in the sera of adult cholera patients at the acute stage of infection. Elevated levels of the nitric oxide (NO*) metabolites (nitrite and nitrate [NO(2)(-) and NO(3)(-)]) were detected in plasma but not in urine. The activity of the scavenger of reactive oxygen species, superoxide dismutase, was higher in the plasma of adults immediately after the onset of disease, suggesting that an active scavenging of reactive oxygen species was taking place. The concentration of 8-iso-prostaglandin F(2 alpha) remained unchanged in the systemic and mucosal compartments in the study subjects. After the recovery of patients from cholera, the concentration of the majority of the metabolites decreased to baseline levels by day 30 after the onset of infection. Immunohistochemical staining showed increased tissue expression of MPO, Lf, and inducible nitric oxide synthase at the acute stage in the duodenal biopsies of adults and rectal biopsies obtained from children with cholera. Very little difference was seen in the levels of the different inflammatory mediators in patients infected with V. cholerae O1 or the encapsulated V. cholerae O139. In summary, these results suggest that elevated concentrations of Lf, MPO, PGE(2), LTB(4), and NO*, as well as other metabolites, during the acute stage of the disease indicate that the innate defense system, as well as the inflammatory process, is activated in both adults and pediatric patients infected with V. cholerae O1 and O139.