An experimental analysis of the role of bottle cells and the deep marginal zone in gastrulation ofXenopus laevis

1981 ◽  
Vol 216 (1) ◽  
pp. 81-101 ◽  
Author(s):  
R. E. Keller
Keyword(s):  
Experimental Analysis ◽  
Marginal Zone

scholarly journals INFECTIOUS AETIOLOGY OF MARGINAL ZONE LYMPHOMA AND ROLE OF ANTI-INFECTIVE THERAPY

2016 ◽  
Vol 8 ◽  
pp. 2016006 ◽  
Author(s):  
Salvatore Perrone ◽  
Gianna Maria D'Elia ◽  
Alessandro Pulsoni
Keyword(s):  
Malt Lymphoma ◽  
Marginal Zone ◽  
Case Reports ◽  
Lymphocyte Activation ◽  
Chlamydia Psittaci ◽  
Gastric Malt Lymphoma ◽  
First Line Therapy ◽  
Causative Relationship ◽  
Chronic Hcv

Marginal zone lymphomas have been associated with several infectious agents covering both viral and bacterial pathogens and in some cases a clear aetiological role has been established. Pathogenetic mechanisms are currently not completely understood, however the role of chronic stimulation of the host immune response with persistent lymphocyte activation represents the most convincing explanation for lymphoproliferation. Gastric MALT lymphoma is strictly associated with Helicobacter pylori infection and various eradicating protocols, developed due to increasing antibiotic resistance, represent the first line therapy. The response rate to eradication is good with 80% of response at 1 year; this finding is also noteworthy because recapitulates a cancer cured only by antibacterial approach and it satisfies the Koch postulates of causation, establishing a causative relationship between Hp and gastric MALT lymphoma. Patients with chronic HCV infection have 5 times higher risk to develop MZL, in particular an association with splenic and nodal MZL has been shown in several studies. Moreover, there is evidence of lymphoma regression after antiviral therapy with interferon+ribavirin, thus rising hope that new available drugs, extremely effective against HCV replication, could improve outcome also in HCV-driven lymphomas. The rare cases of MZL localized to orbital fat and eye conjunctivas have been associated with Chlamydia psittaci infection carried by birds. Efficacy of antibacterial therapy against C. psittaci are conflicting and generally poorer thain gastric MALT. Finally some case-reports will cover the relationship between primary cutaneous B-cell Lymphomas and Borrelia Burgdorferi.

Experimental analysis of diet specialization in the snail kite: the role of behavioral conservatism

Oecologia ◽  
1994 ◽  
Vol 100-100 (1-2) ◽  
pp. 54-65 ◽  
Author(s):  
S. R. Beissinger ◽  
T. J. Donnay ◽  
R. Walton
Keyword(s):  
Experimental Analysis ◽  
Diet Specialization ◽  
Snail Kite

scholarly journals Morphometric and Histopathologic Analysis of Lymphoid Depletion in Murine Spleens Following Infection with Brucella abortus strains 2308 or RB51 or an htrA Deletion Mutant

1996 ◽  
Vol 33 (3) ◽  
pp. 282-289 ◽  
Author(s):  
M. V. Palmer ◽  
N. F. Cheville ◽  
F. M. Tatum
Keyword(s):  
Morphometric Analysis ◽  
Brucella Abortus ◽  
Marginal Zone ◽  
White Pulp ◽  
Splenic White Pulp ◽  
Lymphoid Depletion ◽  
Histopathologic Changes ◽  
Histopathologic Analysis ◽  
Marginal Zones

BALB/C mice were inoculated intraperitoneally with suspensions of Brucella abortus strains 2308 or RB51 or an htrA mutant. Spleens were examined on postinoculation day (PID) 2, 4, 7, 10, 15, 21, 30, and 60. Brucellae were cultured in high numbers from the spleens of mice infected with strains 2308 or htrA through PID 60; however, mice infected with strain RB51 cleared the infection between PID 30 and PID 60. Histopathologic changes in spleens from 2308-infected mice were characterized by marked accumulations of macrophages, which expanded marginal zones beginning as early as PID 7 and persisting through PID 60. Morphometric analysis showed a decrease in splenic white pulp in 2308-infected mice at PID 10, which correlated with the peak of bacterial infection. Although this decrease was significant ( P < 0.05) when compared with values at the previous (PID 7) and the following (PID 15) time periods, it was not significantly different from white pulp values noted at PID 2 or PID 4 or the values for control spleens. Spleens from RB51-infected mice showed only mild to moderate accumulations of macrophages in marginal zone areas during the peak of RB51 infection (PID 7-10). Morphometric analysis of RB51-infected spleens showed a decrease in white pulp area, which coincided with peak bacterial numbers. However, this decrease was not significant ( P > 0.05). Spleens from mice infected with the htrA mutant showed moderate to marked accumulations of macrophages in marginal zone areas, which persisted through PID 60. Multifocal necrosis in lymphoid follicles as early as PID 4 was seen in both htrA and 2308 infection. Morphometric analysis of htrA-infected spleens revealed no significant decrease in white pulp and no obvious correlation with bacterial numbers in the spleen. These results suggest that virulent B. abortus does not induce lymphoid depletion significantly below those values seen in noninfected mice; thus, the possible role of lymphoid depletion in the pathogenesis of brucellosis remains questionable.

scholarly journals Modeling Marginal Zone Lymphomagenesis

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 31-31
Author(s):  
Victor Yazbeck ◽  
Ian McConnell ◽  
Emily Harris ◽  
Joseph Lownik ◽  
Ariel Sindel ◽  
...  
Keyword(s):  
Lymph Nodes ◽  
B Cell ◽  
Marginal Zone ◽  
Pi3k Pathway ◽  
Marginal Zone Lymphoma ◽  
Mtor Pathway ◽  
Genetically Engineered Mouse Model ◽  
Hodgkin's Lymphomas

Introduction: Indolent B-Cell Non-Hodgkin's Lymphomas (NHL) represent a heterogeneous group of lymphoproliferative malignancies, that remain largely incurable. Marginal zone lymphomas (MZL) are the second most common subtype of indolent NHL, and lack a unique cytogenetic identifying abnormality. The B-cell receptor signaling pathway is activated in B-cell malignancy and mediates its activity mainly through the Phosphoinositide 3-kinase (PI3K) pathway. Furthermore, novel PI3K inhibitors, such as copanlisib and parsaclisib, have shown impressive clinical activity in several indolent lymphomas including MZL. This further supports the important role of the PI3K pathway in the pathogenesis of this tumor. Therefore, we hypothesized that the PI3K-mTOR pathway is sufficient for driving the pathogenesis of MZL. Methods: In order to test our hypothesis, we generated a genetically engineered mouse model carrying heterozygous global knockout alleles of both the tumor suppressor genes Phosphatase and Tensin Homolog (PTEN) and Liver Kinase B1 (LKB1). This led to over-activation of the PI3K-mTOR pathway in all mouse tissues. We closely monitored these mice for tumor formation via weekly physical examinations for several months. Upon tumor detection, the mouse was sacrificed, and tumors were sectioned for histological characterization. In order to generate a more specific model of B cells, and more accurately mimic the underlying human disease, we used the Cre-LoxP system to create the CD19-Cre-PTENfl/fl-LKB1fl/fl. Results: Thirty mice of global KO PTEN+/- LKB1 +/- died or were sacrificed due to disease progression, defined as either lymph node enlargement and/or splenomegaly. All mice showed either abnormal lymphadenopathy or splenomegaly. By Kaplan-Meier analysis, we saw a steady decrease in both tumor-free and overall survival after 3 months of age. Utilizing the product limit method, the median survival time was 6 months (95% CI: 6, 8). A total of 51 lymph nodes were sent for immunohistochemistry and pathological characterization. Of the 51 nodes, 61.5% (N=32) showed indolent Non-Hodgkin's Lymphoma, 25% (N=13) were atypical, and 11.5% (N=6) were reactive. All lymph nodes with indolent NHL were of MZL subtype. Compared to wild type (n=3), the new CD19-Cre-PTENfl/fl -LKB1fl/fl (n=3) showed an overall increase in spleen mass (120 vs 196 mg, p=0.0564), % B1 cells (4% vs 59%, p= 0.0075), % MZ cells (5% vs 30%, p=0.0547), % plasma cells (1% vs 12%, p=0.0729), and decrease in % FO cells (80% vs 12%, p=0.0003) by flowcytometry. Further characterization of the new model is currently underway. Conclusion: Marginal zone lymphoma remains an incurable lymphoma that lacks reliable preclinical models. Our data provides, for the first time, a proof of concept on the role of the PI3K-mTOR pathway in the pathogenesis of marginal zone lymphoma and paves the way for future studies understanding the biology of this disease, and developing rational therapies for this incurable malignancy. Disclosures Yazbeck: Celgene: Consultancy; AstraZeneca: Consultancy; Gilead: Research Funding; Seattle Genetics: Consultancy; Verastem: Speakers Bureau.

Intrathalline variability of some structural and physical parameters in the lichen genus Lasallia

1994 ◽  
Vol 72 (4) ◽  
pp. 415-428 ◽  
Author(s):  
F. Valladares ◽  
C. Ascaso ◽  
L. G. Sancho
Keyword(s):  
Chlorophyll Content ◽  
Marginal Zone ◽  
Central Zone ◽  
Intermediate Zone ◽  
Physical Parameters ◽  
Main Role ◽  
Active Growth ◽  
Lasallia Pustulata ◽  
Water Holding

The intrathalline variability of several physical and anatomical parameters of two lichens, Lasallia hispanica and Lasallia pustulata within the family Umbilicariaceae, was studied. In each thallus three zones or concentric rings were considered: the central zone, which includes the umbilicus, the intermediate zone, and the marginal zone. The study focussed on the thickness of the thallus and its layers, the increase of surface area and volume with hydration, the sample densities in dry and wet states, several stereological parameters (especially the volume and surface density of both symbionts related to each layer and to the thallus as a whole), and the chlorophyll content. Only slight differences were revealed between the two species, but significant intrathalline variation was observed. A marked decrease in the total chlorophyll content coincided with the thickening of the thallus from the periphery to the centre. The chlorophyll content of individual algal cells, however, presented an inverse gradient. The results suggest that the main role of the dense central zone would be as a water-holding zone while the active growth in the intermediate zone could counteract the continuous erosion of the marginal zone of these umbilicate lichens. Key words: Lasallia, intrathalline variability, mycobiont, photobiont, stereology, thallus density.

A role for the vegetally expressed Xenopus gene Mix.1 in endoderm formation and in the restriction of mesoderm to the marginal zone

Development ◽  
1998 ◽  
Vol 125 (13) ◽  
pp. 2371-2380 ◽  
Author(s):  
P. Lemaire ◽  
S. Darras ◽  
D. Caillol ◽  
L. Kodjabachian
Keyword(s):  
Marginal Zone ◽  
Ectopic Expression ◽  
Homeobox Gene ◽  
Early Response ◽  
Endoderm Differentiation ◽  
Head Formation ◽  
Mutual Repression ◽  
Regulatory Loop ◽  
Strong Activator

We have studied the role of the activin immediate-early response gene Mix.1 in mesoderm and endoderm formation. In early gastrulae, Mix.1 is expressed throughout the vegetal hemisphere, including marginal-zone cells expressing the trunk mesodermal marker Xbra. During gastrulation, the expression domains of Xbra and Mix.1 become progressively exclusive as a result of the establishment of a negative regulatory loop between these two genes. This mutual repression is important for the specification of the embryonic body plan as ectopic expression of Mix.1 in the Xbra domain suppresses mesoderm differentiation. The same effect was obtained by overexpressing VP16Mix.1, a fusion protein comprising the strong activator domain of viral VP16 and the homeodomain of Mix.1, suggesting that Mix.1 acts as a transcriptional activator. Mix.1 also has a role in endoderm formation. It cooperates with the dorsal vegetal homeobox gene Siamois to activate the endodermal markers edd, Xlhbox8 and cerberus in animal caps. Conversely, vegetal overexpression of enRMix.1, an antimorphic Mix.1 mutant, leads to a loss of endoderm differentiation. Finally, by targeting enRMix.1 expression to the anterior endoderm, we could test the role of this tissue during embryogenesis and show that it is required for head formation.

Stage IV marginal zone B-cell lymphoma - prognostic factors and the role of rituximab: Consortium for Improving Survival of Lymphoma (CISL) study

2010 ◽  
Vol 101 (11) ◽  
pp. 2443-2447 ◽  
Author(s):  
Sung Yong Oh ◽  
Won Seog Kim ◽  
Jin Seok Kim ◽  
Seok Jin Kim ◽  
Suee Lee ◽  
...  
Keyword(s):  
Prognostic Factors ◽  
B Cell ◽  
Marginal Zone ◽  
Cell Lymphoma ◽  
Stage Iv ◽  
B Cell Lymphoma
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