Expression of TP73L is a helpful diagnostic marker of primary mediastinal large B-cell lymphomas.

Primary mediastinal large B-cell lymphoma is a well-defined lymphoma entity whose molecular pathogenesis is incompletely understood and also lacking well-established diagnostic markers. Recently, the presence of overlapping features between classical Hodgkin's lymphoma and primary mediastinal large B-cell lymphoma was highlighted by gene expression profiling as well as morphological studies. We investigated the expression of TP73L (commonly known as p63) isoforms in primary mediastinal large B-cell lymphoma at both protein and mRNA level, and demonstrated the exclusive presence of transactivating (TA) isoforms in all cases. We also demonstrated that TP73L is expressed in a subset of germinal center B-cells, as well as in some diffuse large B-cell lymphomas, but it is never present in classical Hodgkin lymphoma. Nodular lymphocyte predominant Hodgkin's lymphoma also showed TP73L positivity by immunohistochemistry. Isoform analysis by real-time PCR showed that TA-TP73Lalpha is the most represented in primary mediastinal large B-cell lymphoma, but TA-TP73Lgamma is the most differentially expressed in comparison to both germinal center B-cells and diffuse large B-cell lymphomas. TP73L expression proved a useful diagnostic marker of primary mediastinal large B-cell lymphoma, and gave new insights in to the molecular pathways playing a role in this lymphoma.     

Large cell carcinoma of lung: On the verge of extinction?

Pulmonary large cell carcinoma is a tumor whose existence as a defined entity has been challenged in recent years in the wake of advances in techniques to subtype lung cancer. Large cell carcinoma has been defined in the past as a tumor that lacks morphologic evidence of either glandular or squamous differentiation. This rather vague definition and the inclusion of more specific entities such as large cell neuroendocrine carcinoma, basaloid carcinoma, lymphoepithelioma-like carcinoma, clear cell carcinoma, and large cell carcinoma with rhabdoid phenotype as subtypes of large cell carcinoma has not only diluted the homogeneity of this entity but has also contributed to its use as a “wastebin” category for tumors lacking a definitive morphologic pattern. Today, there is increasing evidence that a large proportion of these tumors can be subtyped further using modern immunohistochemical and molecular methods. This is of special value not only from a diagnostic point of view but becomes increasingly important in terms of treatment choice since the selection of therapeutic modalities is often based on specific tumor histology. When viewed in this light, large cell carcinoma of the lung—as defined today—appears to be an outdated entity that needs to be reevaluated taking into account not only light microscopic findings but also the results of adjunct techniques such as immunohistochemistry and molecular profiling so that patients can benefit from more targeted therapies. This review examines the entity of pulmonary large cell carcinoma from these aspects and tries to delineate a practical diagnostic approach until further redefinition of this tumor is in place.     

Recurrence of nodal diffuse large B-cell lymphoma as intravascular large B-cell lymphoma: is an intravascular component at initial diagnosis predictive?

We report a case of a 59-year-old man who first presented with a nodal diffuse large B-cell lymphoma that later relapsed as an intravascular large B-cell lymphoma. In the initial biopsy specimen, a few intranodal small vessels that contained large lymphoma cells were noted. After 8 months of multiagent chemotherapy, clinical remission was attained. Two years after the initial diagnosis of nodal diffuse large B-cell lymphoma, the patient presented with a rapid onset of multiorgan failure, which at autopsy was shown to be due to intravascular large B-cell lymphoma. Molecular genetic studies showed that these 2 lymphomas had immunoglobulin heavy-chain gene rearrangements that were of identical size, suggesting that they were derived from the same clone. To our knowledge, this is the first report of a nodal large B-cell lymphoma that relapsed as an intravascular large B-cell lymphoma. Although this report is of only a single case, the presence of a relatively inconspicuous intravascular component in an otherwise typical nodal large B-cell lymphoma may be predictive and could affect clinical decisions regarding diagnosis, monitoring, and prognosis of such lymphomas.     

Semiquantitative multiplex PCR: a useful tool for large rearrangement screening and characterization

Methods presently employed for detection of large rearrangements have several drawbacks, such as the amount of sample and time required, technical difficulty, or the probability of false-negative carriers. Using the low-density-lipoprotein receptor (LDLR) gene, whose mutations are responsible for familial hypercholesterolemia (FH), we have developed a procedure to detect large rearrangements in this gene based on semiquantitative PCR, with important improvements as compared to previous methods. Our method covers the complete LDLR gene and introduces an internal control in the reaction. The procedure discriminates the four different large rearrangements (two deletions and two insertions) that we have used as positive mutation controls (Valencia-1 to -5). All altered exons from each rearrangement are identified. Furthermore, when families from probands carrying these large rearrangements (34 members) were analyzed, our results agreed with those obtained previously with Southern blot. We have also analyzed a sample of 110 unrelated FH probands and the method has correctly identified the two different large rearrangements present and insertions or deletions as small as 1 bp. In conclusion, the method we present allows the identification of large rearrangements affecting exons of the gene, including small insertions or deletions or complete gene deletion. In addition, it constitutes a first characterization step of rearrangements, and is easy to carry out fast, and can be applied to the analysis of any gene.     

Enhanced binding to origin DNA at low pH enables easy detection of polyomavirus large T antigen by gel mobility shift assay of unfixed complexes

Enhanced, stable binding by polyomavirus large T antigen to the viral DNA replication origin at pH 6 allowed the development of a gel mobility shift assay for the detection of large T antigen. Such assays were not possible at pH 7.6 without previous fixation, due to instability of the complexes. We demonstrated that the gel mobility shift assay at pH 6 is very sensitive, allowing the detection of as little as 5 ng large T antigen, and is highly specific for DNA containing G(A/G)GGC target sequences. This method was used to detect large T antigen in crude cell lysates from transformed yeast cell lines or nuclear extracts from infected insect cells. Large T antigen-DNA complexes remained at or near the loading well in 5% acrylamide or 1.5% agarose gels, indicating that these complexes are very large. Glycerol gradient analysis showed that protein-DNA complexes formed at pH 6 were massive, and that large T antigen also formed large complexes when incubated at low pH in the absence of DNA. These results show that pH has a major effect on binding of large T antigen to its multiple target sites in the viral origin of DNA replication, presumably by affecting protein-protein interactions that are important for the stability of large T antigen-DNA complexes.     

Synaptology of the command (pacemaker) nucleus in the brain of the weakly electric fish, Sternarchus (Apteronotus) albifrons

The high frequency electric emission of the weakly electric fish Sternarchus (Apteronotus) albifrons depends on the pacemaker activity of a specific brainstem nucleus located in the ventral part of the rhombencephalic reticular formation. The general morphology and fine structure of this nucleus has been investigated, with particular reference to its synaptic connections.Three neuronal components could be distinguished in the nucleus; namely large cells of 80–100 μm diameter, small cells of 30–50 μm diameter and bundles of thin, myelinated fibres. These elements are embedded in a network of thick myelinated fibres. The large cells have a few small and short dendrites whereas the small neurons have long branching dendrites. Large and small neurons possess thick myelinated axons, but only those of the latter show branching patterns and send collaterals which have intranuclear courses only. Two types of synaptic terminals have been found on both neurons: large club endings exclusively with gap junctions and small bouton-like terminals with polarized chemical synapses. Serial semi-thin and ultra-thin sections revealed that the large club endings belong to the pacemaker cells, whereas the small terminals are found in the thin myelinated axons of extranuclear origin.The findings indicate that the small neurons are connected 1) to each other and 2) to the large neurons, by way of their large myelinated axons. Both, small (pacemaker) as well as large (relay), neurons receive chemical synapses from myelinated fine fibers probably originating from higher encephalic centers. Thus, electric organ discharge rhythm can be modulated at the level of pacemaker as well as of the relay cells. No somatosomatic, dendrodendritic or dendrosomatic connections were found between large, small or large and small cells.     

Analysis of localization and function of the COOH-terminal corresponding site of cytochrome b558 in fish neutrophils.

Using an antibody against the synthetic peptide corresponding to the COOH-terminal region of human cytochrome b558 large subunit, a broad band was specifically detected in neutrophil lysates from 6 marine fish and 2 freshwater fish by western blotting. Immunofluorescence assay showed that the antibody recognized the epitopes in eel and tilapia neutrophils permeabilized with detergent. These results suggest that the cytochrome b large subunit universally exists in fish neutrophils and that the epitopes are exposed to the cytoplasmic side of fish neutrophils as well as human neutrophils. Furthermore, a synthetic peptide corresponding to the COOH-terminus of the large subunit apparently blocked superoxide production in a specific and dose-dependent fashion in eel and tilapia neutrophils, indicating that the region equivalent to the COOH-terminus of cytochrome b large subunit is responsible for superoxide generation in fish neutrophils.     

Comparison of clinical outcomes and natural morphologic changes between sequestered and large central extruded disc herniations

A prospective and longitudinal investigation concerning clinical outcomes and morphologic changes of large lumbar disc herniations by MR imaging. To compare the clinical outcomes and the natural morphologic changes of between sequestered and large central extruded disc herniations. The spontaneous disappearance or diminution of large herniated lumbar discs in the spinal canal is known. Poor clinical outcome and small changes of herniated discs have been shown for large central extruded disc herniations with conservative treatment. The study population consisted of 22 patients with sequestration and a large central as extrusion established by an MR imaging study. Seventeen (11 patients with sequestration, and 6 patients with a large central extrusion) patients underwent a follow-up MR imaging study. The size of the herniated disc was measured on serial MR imaging studies, and the changes in size were classified into four categories. Clinical evaluations were also performed using a visual analogue scale (VAS), the Oswestry low back pain disability questionnaire, the straight leg raising test (SLRT) and so forth. Both the sequestered and large central extruded disc herniations showed a successful clinical outcome after conservative treatment in 17 of 22 patients (77%) in total: 11 of 13 patients (85%) with sequestered disc herniations, and 6 of 9 patients (67%) with large central extruded disc herniations. VAS and Oswestry disability scoring showed a greater change in the group with sequestration than in the group with large central extrusions. In the group with sequestration, seven patients reported the disappearance of herniated disc materials, and four patients showed a marked decrease in the size of their herniated discs in follow-up MR images. However, in the group with large central extrusions, only two patients showed a decrease in the size of their herniated discs. Large central extruded disc herniations can be treated successfully by conservative treatment. Outcomes seemed to be as good as or slightly inferior to those of sequestered disc herniations. However, a greater morphologic decrease in the herniated discs occurred more frequently for sequestered disc herniations than for large central extruded disc herniations.     

Calcium channels and the release of large dense core vesicles from neuroendocrine cells: spatial organization and functional coupling

The release of large dense core vesicles (LDCV) by neuroendocrine cells displays a very similar calcium dependence as found in synapses, yet, the organization of channels and vesicles is quite different. Various biophysical properties of the release process, notably a large delay (>10 ms) between excitation and release and a high impact of mobile calcium buffers, suggest that, generally, vesicles and channels do not co-localize as in synapses, but are separated by a distance of 100-300 nm. This review focuses on the consequences of this organization for the functional coupling of calcium channels to LDCV-release in neuroendocrine cells. The large distance between LDCV and calcium channels in neuroendocrine cells obviates molecular interactions between channels and fusion peptides and implies that each type of calcium channel may be involved in release. Thus, preferential functional coupling of specific calcium channel types to the exocytotic process may be completely lacking, as in melanotropes. Alternatively, it may be present to some extent to induce differences in coupling efficacy between channel types, as in calf chromaffin cells and mouse pancreatic beta-cells. Physiological mechanisms, like recruitment of channels through facilitation processes or suppression of channels through inactivation, may change coupling characteristics during activity. Due to the large distance between channels and vesicles, single action potentials (APs) are usually insufficient to elicit release, and the coupling between individual APs and release is loose. Most neuroendocrine cells are therefore seen to fire in bursts, like pancreatic beta-cells. Furthermore, a large variation in shape and duration of the APs, with APs of up to 300 ms as in melanotropes, acts as another mechanism to enhance stimulus secretion coupling.     

An immunoelectron microscopic study of immunoglobulin G in the postcapillary venules of normal and nude mouse lymph nodes.

Ultrastructural localization of immunoglobulin G (IgG) in the postcapillary venules (PVC) of normal and nude mouse lymph nodes was examined in thin sections which had been stained sequentially with primary exposure to biotin-conjugated goat anti-mouse IgG serum and a secondary immersion in a ferritin-linked avidin (IF). In the normal mouse PCV, reaction products showing IgG-binding sites were detected as large IF clusters on the luminal membrane of the endothelial cells, as small IF clusters in the intercellular spaces between the endothelial cells and some migrating lymphocytes, and as uniform precipitates of large numbers of IF particles in the basement membrane. By contrast, nude mouse PCV retained a few or almost no IgG-binding sites in portions comparable to those observed in the normal mouse. A relatively large number of plasma cells in the lymphoid stroma of both strains possessed large IF clusters on the cell surfaces. The significance of the IgG localization in the PCV of the two strains is discussed in relation to the mechanism of lymphocyte recirculation.     

Primary mediastinal large B-cell lymphoma arising from thyroid in a renal recipient with Hashimoto’s thyroiditis

Primary mediastinal large B-cell lymphoma is a subtype of diffuse large B-cell lymphoma, arising in the mediastinum from putative thymic B-cell origin with distinctive clinical and genetic features. Generally, primary mediastinal large B-cell lymphoma is believed as only deriving in the mediastinum. The current study presents a rare case of primary mediastinal large B-cell lymphoma which arising from thyroid in a renal recipient with Hashimoto’s thyroiditis. Moreover, we devoted a discussion to the relationship among primary mediastinal large B-cell lymphoma, immunomodulatory therapy and autoimmune diseases. The immunologic derangement induced by long-term immunomodulatory therapy and Hashimoto’s thyroiditis may be the possible cause for the ectopic lymphoma.     

Intravascular large B-cell lymphoma

A rare type of diffuse large B-cell lymphoma, intravascular large B-cell lymphoma primarily affects the middle-aged to elderly population, with a slight predominance in men. By the time of presentation, most patients have advanced, disseminated disease, and often the diagnosis is made at autopsy. Patients may present with any of a myriad of symptoms, with any tissue potentially being infiltrated. Central nervous system and cutaneous involvement is common, as is the presence of B symptoms including fever, weight loss, and night sweats. Morphologically, growth of neoplastic cells is restricted to the lumen of small vessels. The cells are large, with 1 or more prominent nucleoli, scant cytoplasm, and frequent mitotic figures, and are commonly positive for cluster of differentiation markers 79a, 20, and 19, as well as MUM1/IRF4 and Bcl-2. Intravascular large B-cell lymphoma is aggressive, and without treatment is rapidly fatal.     

Localization of Spirochetes with the Structural Characteristics of Treponema hyodysenteriae in the Lesions of Swine Dysentery

The large intestines of pigs with swine dysentery were examined by phase, light, and electron microscopy at intervals up to 11 days after oral inoculation with mucosal scrapings from infected pigs. Large spirochetes with the structural characteristics of Treponema hyodysenteriae were found only in infected pigs and were first observed in small numbers in the lumen of the large intestine 2 days after inoculation. Numerous large spirochetes were present on the luminal surface and in mucosal crypts as lesions developed. Degenerative changes were first observed in the apical portion of epithelial cells in close contact with large spirochetes. These large spirochetes were found intact in goblet cells and epithelial cells in the early stages of the disease and were numerous within degenerating epithelial cells as lesions became more advanced. Invasion beyond the lamina propria was not detected. These observations demonstrated the relationship between pathogenic large spirochetes and the mucosa of the large intestine in a specific disease, swine dysentery.     

Neuronal circuitry in the nucleus lateralis of the cerebellum

Summary This study summarizes the nervous circuitry of the lateral nucleus from evidence presented in the previous papers in this investigation. The large and small neurons receive three types of extracerebellar afferent fibers—collaterals of climbing fibers and mossy fibers on their way to the cerebellar cortex, and fluorescent CAT fibers of two varieties. The large projection neurons receive a large inhibitory corticonuclear input via synapses of Purkinje cell axons upon their somatic and dendritic surfaces, as well as upon initial axonal segments. On their way into the superior cerebellar peduncle, the axons of these neurons send recurrent collateral branches, which provide a positive feedback circuit within the nucleus. The small inhibitory interneurons depend to a large extent on the activating input upon their dendrites; their corticonuclear input from Purkinje cells is less numerous than that of large neurons. Their myelinated axons provide a rapid system of internal inhibitory control. In cases in which the axons are long and leave the nucleus, like those emitted by the small neurons in the medial hilus zone, they may provide a route of internuclear communication.The arrangements of neurons in the columnar zone are reviewed. The large neurons are oriented at an angle to incoming extracerebellar fibers and present a profile to the Purkinje cell axon. The interneuronsare tilted at ninety degrees to the dendritic trees of the large neurons, and they receive a larger extracerebellar afferent input. Whereas the corticonuclear input to the large columnar neurons probably expresses a ratio of one Purkinje cell to one large neuron, the tilt assumed by the small neurons may increase this ratio. Electron microscopy has shown that small neurons receive a smaller corticonuclear input than large neurons. Elsewhere in the swirled zones of the nucleus, these influences are less precisely oriented, and therefore less restrictive interplay exists between corticonuclear influences and the large multipolar neurons.Supported in part by U.S. Public Health Service grants NS10536, NS03659, Training grant NS05591 from the National Institute of Neurological Diseases and Stroke, and a William F. Milton Fund Award from Harvard University.     

Simian virus 40 large T overcomes p300 repression of c-Myc

We previously showed that in quiescent cells p300/CBP negatively regulates the cell cycle G1-S transition by keeping c-Myc in a repressed state and that adenovirus E1A induces c-Myc by binding to p300/CBP. Studies have shown that p300/CBP binding to simian virus 40 large T is indirect and mediated by p53. By using a series of large T mutants that fail to bind to various cellular proteins including p53 as well as cells where p300 is overexpressed or p53 is knocked down, we show that the association of large T with p300 contributes to the induction of c-Myc and the cell cycle. The induction of c-Myc by this mechanism is likely to be important in large T mediated cell cycle induction and cell transformation.     

Using JPEG 2000 Interactive Protocol to Stream a Large Image or a Large Image Set

The electronic health record (EHR) is expected to improve the quality of care by enabling access to relevant information at the diagnostic decision moment. During deployment efforts for including images in the EHR, a main challenge has come up from the need to compare old images with current ones. When old images reside in a different system, they need to be imported for visualization which leads to a problem related to persistency management and information consistency. A solution consisting in avoiding image import is achievable with image streaming. In this paper we present, evaluate, and discuss two medical-specific streaming use cases: displaying a large image such as a digital mammography image and displaying a large set of relatively small images such as a large CT series.     

The fine structure of large cell undifferentiated carcinoma of the lung. Evidence for its relation to squamous cell carcinomas and adenocarcinomas

The light microscopic diagnosis of large cell undifferentiated carcinoma of the lung is known to be highly subjective and shows poor interobserver reproducibility; the very existence of this tumor as a separate entity has been challenged. The ultrastructure of seven large cell undifferentiated carcinomas was examined in an attempt to determine whether they were merely poorly differentiated adenocarcinomas and squamous cell carcinomas, or actually represented an entirely separate class of tumors. Four large cell undifferentiated carcinomas demonstrated intra- and intercellular lumina and were designated adenocarcinomas. In three cases there were well formed desmosomes with numerous tonofilaments and intercellular bridges. These tumors were classified as squamous cell carcinomas. An eighth tumor metastatic to the abdominal wall also showed the features of squamous carcinoma. In addition, all tumors contained a variable population of primitive cells without identifying features. The large cell undifferentiated carcinomas were compared ultrastructurally with eight cases of poorly differentiated adenocarcinomas and squamous cell carcinomas classified by light microscopy. These tumors were morphologically similar, but contained fewer primitive cells and greater numbers of differentiated cells. Cells with a clear cytoplasm as seen by light microscopy were present in both the large cell undifferentiated and poorly differentiated groups; these cells contained variable amounts of glycogen but were otherwise similar to the nonclear cells. It is suggested that most of the subcategories of large cell undifferentiated carcinoma represent very poorly differentiated adenocarcinomas and squamous carcinomas.     

Clinicopathologic implications of tissue inhibitor of metalloproteinase-1-positive diffuse large B-cell lymphoma.

The tissue inhibitor of metalloproteinase-1 (TIMP-1) is a stromal factor that promotes plasmablastic differentiation, and the survival of germinal center B-cells. The expression of TIMP-1 is known to be correlated with a subset of non-Hodgkin lymphoma at the mRNA level, and Epstein-Barr virus infection in vitro. To characterize TIMP-1(+) diffuse large B-cell lymphoma, TIMP-1 expression was investigated in tissue microarrays from 182 cases of de novo diffuse large B-cell lymphoma and compared with prognostic factors, immunophenotypes, and Epstein-Barr virus infection status. TIMP-1 was expressed not only in tumor cells themselves, in 14 of 182 cases (8%), designated as TIMP-1(+) diffuse large B-cell lymphoma, but also in stromal cells like fibroblasts and endothelial cells. In univariate analysis and hierarchical clustering, our findings suggest that TIMP-1 expression may represent a distinct subgroup. In multivariate analysis, TIMP-1(+) diffuse large B-cell lymphoma (n=14) was associated with unfavorable outcomes compared to TIMP-1(-) diffuse large B-cell lymphoma (n=168) (odds ratio=2.5, P=0.049). Together with TIMP-1 expression, age (greater than 60 years), the presence of B-symptoms, abnormal lactate dehydrogenase level, or more advanced stage (III/IV) was correlated with a poor overall survival. However, TIMP-1 expression in diffuse large B-cell lymphoma was not correlated with other prognostic factors including: clinical stage, international prognostic index score, and nongerminal center B-cell phenotype, as well as Epstein-Barr virus infection. Our results suggest that TIMP-1 expression may be an independent negative prognostic factor in patients with diffuse large B-cell lymphoma.