Neural remodeling in retinal degeneration

Mammalian retinal degenerations initiated by gene defects in rods, cones or the retinal pigmented epithelium (RPE) often trigger loss of the sensory retina, effectively leaving the neural retina deafferented. The neural retina responds to this challenge by remodeling, first by subtle changes in neuronal structure and later by large-scale reorganization. Retinal degenerations in the mammalian retina generally progress through three phases. Phase 1 initiates with expression of a primary insult, followed by phase 2 photoreceptor death that ablates the sensory retina via initial photoreceptor stress, phenotype deconstruction, irreversible stress and cell death, including bystander effects or loss of trophic support. The loss of cones heralds phase 3: a protracted period of global remodeling of the remnant neural retina. Remodeling resembles the responses of many CNS assemblies to deafferentation or trauma, and includes neuronal cell death, neuronal and glial migration, elaboration of new neurites and synapses, rewiring of retinal circuits, glial hypertrophy and the evolution of a fibrotic glial seal that isolates the remnant neural retina from the surviving RPE and choroid. In early phase 2, stressed photoreceptors sprout anomalous neurites that often reach the inner plexiform and ganglion cell layers. As death of rods and cones progresses, bipolar and horizontal cells are deafferented and retract most of their dendrites. Horizontal cells develop anomalous axonal processes and dendritic stalks that enter the inner plexiform layer. Dendrite truncation in rod bipolar cells is accompanied by revision of their macromolecular phenotype, including the loss of functioning mGluR6 transduction. After ablation of the sensory retina, Müller cells increase intermediate filament synthesis, forming a dense fibrotic layer in the remnant subretinal space. This layer invests the remnant retina and seals it from access via the choroidal route. Evidence of bipolar cell death begins in phase 1 or 2 in some animal models, but depletion of all neuronal classes is evident in phase 3. As remodeling progresses over months and years, more neurons are lost and patches of the ganglion cell layer can become depleted. Some survivor neurons of all classes elaborate new neurites, many of which form fascicles that travel hundreds of microns through the retina, often beneath the distal glial seal. These and other processes form new synaptic microneuromas in the remnant inner nuclear layer as well as cryptic connections throughout the retina. Remodeling activity peaks at mid-phase 3, where neuronal somas actively migrate on glial surfaces. Some amacrine and bipolar cells move into the former ganglion cell layer while other amacrine cells are everted through the inner nuclear layer to the glial seal. Remodeled retinas engage in anomalous self-signaling via rewired circuits that might not support vision even if they could be driven anew by cellular or bionic agents. We propose that survivor neurons actively seek excitation as sources of homeostatic Ca(2+) fluxes. In late phase 3, neuron loss continues and the retina becomes increasingly glial in composition. Retinal remodeling is not plasticity, but represents the invocation of mechanisms resembling developmental and CNS plasticities. Together, neuronal remodeling and the formation of the glial seal may abrogate many cellular and bionic rescue strategies. However, survivor neurons appear to be stable, healthy, active cells and given the evidence of their reactivity to deafferentation, it may be possible to influence their emergent rewiring and migration habits.     

The Role of Interferon in the Treatment of Chronic Myelogenous Leukemia: Results and Prospects

INTRODUCTION Philadelphia positive chronic myelogenous leukemia (Ph¹+ CML) is a myeloproliferative disorder of clonal origin, due to neoplastic transformation of a pluripotent stem cell, and characterized by excessive proliferation of hemopoietic precursors and expansion of the myeloid cellular mass¹. In 90-95% of cases, the disease is associated with a chromosomal abnormality, the Ph¹ chromosome, derived from a reciprocal translocation t(9;22) (q34;q11) between chromosomes 9 and 22². The translocation of the proto-oncogene c-abl from its normal location on chromosome 9 to the break-point cluster region (bcr) of chromosome 22 involves the formation of a chimeric gene (abl-bcr), the product of which is a protein with increased tyrosine-kinase activity^3,4. It seems likely that the bcr rearrangement plays an important role in the pathogenesis of CML. Characteristically, the disease presents two phases: a “benign” or chronic phase lasting about 3 years, well controlled by chemotherapy, and a terminal blastic phase, refractory to chronic-phase treatments, invariably fatal in 3-6 months and frequently associated with cytogenetic abnormalities additional to the Ph¹.     

CD117 immunoreactivity in high-grade neuroendocrine tumors of the lung: a comparative study of 39 large-cell neuroendocrine carcinomas and 27 surgically resected small-cell carcinomas

Little is known about CD117 prevalence and clinicopathological implications in pulmonary large-cell neuroendocrine carcinoma. We studied CD117 immunoreactivity in surgical specimens from 39 large-cell neuroendocrine carcinomas of stages I–III and 27 limited-disease small-cell carcinomas, 56 typical and atypical carcinoids of the lung, and 10 neuroendocrine tumorlets, including the membrane and cytoplasmic immunostaining patterns. Membrane CD117 immunoreactivity in 5% or more tumor cells was documented in 30 (77%) large-cell neuroendocrine carcinomas and 18 (67%) small-cell carcinomas and 4 (7%) carcinoids, whereas cytoplasmic labeling was seen in 17 (44%) large-cell neuroendocrine carcinomas, 19 (70%) small-cell carcinomas, and 3 (5%) carcinoids. None of the neuroendocrine cells of the normal bronchial epithelium and of 10 tumorlets showed any CD117 immunoreactivity. Cytoplasmic immunostaining was more prevalent in small-cell carcinomas, whereas membrane labeling did not differ between the two types of high-grade carcinomas. Downregulation of CD117 by neoadjuvant chemotherapy was seen in large-cell neuroendocrine carcinomas but not small-cell carcinomas. Multiple linear regression analysis demonstrated a marginal association between cytoplasmic CD117 immunoreactivity and regional lymph node metastasis in small-cell carcinomas but not large-cell neuroendocrine carcinomas. There was no association between CD117 immunoreactivity and survival in either small-cell carcinoma or large-cell neuroendocrine carcinoma patients.     

Solid and cystic papillary neoplasm of the pancreas: A clinico-cytopathologic and immunocytochemical study of five new cases diagnosed by fine-needle aspiration cytology and a review of the literature

We report here on five new cases of solid and cystic papillary neoplasm (SCPN) of the pancreas diagnosed by fine-needle aspiration cytology (FNAC). All cytologic samples were obtained by ultrasonography, and the smears were conventionally fixed and stained. Special histochemical and immunocytochemical stains were also performed in some samples. Cytology revealed in all but one case numerous pseudopapillary structures composed of fibrovascular stalks lined with one or more layers of bland-appearing, uniform tumor cells. The tumor cells had round-to-oval euchromatic nuclei with frequently folded smooth contours and one or two small nucleoli. Their cytoplasm often contained eosinophilic, PAS-positive, and diastase-resistant inclusions. Foamy cells, psammoma bodies, blood, and cellular debris were found in the background. The criteria for the differential diagnosis versus other pancreatic lesions are discussed in some detail, as is the role of immunocytochemistry (ICC). In the literature, only 28 cases of cytologically investigated SCPN have been reported to the best of our knowledge. The most helpful criteria for the conclusive identification of SCPN by FNAC include the pseudopapillary arrangement with bland-appearing tumor cells, and, especially, the finding of acidophilic, PAS-positive, and diastase-resistant cytoplasmic granules. © 1995 Wiley-Liss, Inc.     

Functional and surface phenotype study of lymphocyte subsets in peripheral blood and lymph nodes of breast cancer patients

In an attempt to identify lymphocyte subsets possibly involved in the response to malignant cells, we have studied the lymphocyte surface phenotype by using a panel of monoclonal antibodies on both peripheral blood lymphocytes (PBL) and histologically proven metastatic and nonmetastatic (i.e., "hyperplastic") axillary lymph node lymphocytes (LNL) from eight breast cancer patients. Furthermore, we carried out a functional study by evaluating the response to polyclonal mitogens of the PBL and of the LNL of the same patients. A group of 30 healthy subjects, age and sex matched, were selected as controls for PBL. Six of them, who underwent surgery for nonneoplastic conditions, were selected as controls for LNL. The responsiveness of breast cancer patients' PBL to polyclonal mitogens phytohemagglutinin (PHA) and concanavalin A (Con A) was significantly lower as compared with the control response. The responsiveness of breast cancer patients' metastatic LNL was not different from control LNL for PHA, and it was lower than control LNL for Con A, while the responsiveness of the same metastatic LNL was higher than that of nonmetastatic (i.e., hyperplastic) LNL of patients. Furthermore, the response of hyperplastic LNL was always lower than that of control LNL. The responsiveness of patients' PBL was always lower than that of metastatic LNL, while the responsiveness of patients' PBL vs. hyperplastic LNL was at variance. Regarding the surface phenotype of PBL, there was no difference between those of breast cancer patients and controls concerning the T-cells subsets, while the Leu 7, CD 21 and DR antigens were significantly higher among the breast cancer patients. No significant differences were found between patient metastatic and hyperplastic LNL or between control LNL and patient metastatic or hyperplastic LNL, respectively; only the CD 4 antigen was higher in metastatic than in hyperplastic LNL. A comparison of this surface phenotype between PBL and either metastatic or hyperplastic LNL of breast cancer patients showed values almost constantly significantly higher for PBL vs. either metastatic or hyperplastic LNL, respectively. The results of our study suggest that there is no change in the local-regional immunocompetent cell subsets that may be related to metastasis of breast cancer to regional nodes and to the progression of disease and that circulating T cells in breast cancer include cells expressing activation markers but not showing significant changes in the proportion of entire subpopulations.     

Phase 1 cohort expansion study of LY3023414, a dual PI3K/mTOR inhibitor,in patients with advanced mesothelioma

Investigational New Drugs - BACKGROUND LY3023414 is a selective, ATP competitive inhibitor of class I PI3K isoforms, mTORC1/2 and DNA-PK. A Phase 1 dose escalation, 200 mg twice daily...     

Prognostic role of interleukin-1beta gene and interleukin-1 receptor antagonist gene polymorphisms in patients with advanced gastric cancer.

PURPOSE: A high interleukin-1beta (IL-1B) and interleukin-1 receptor antagonist (IL-RN) ratio underlies an unfavorable proinflammatory status. Also, it seems to be involved in the mechanisms of cancer cachexia and tumor angiogenesis and metastasis. Two single nucleotide polymorphisms in IL-1B gene (IL-1B-511C/T,IL-1B-31T/C) and a variable number of tandem repeat polymorphisms in IL-RN gene (IL-1RNlong/2) enhance the circulating levels of the two cytokines. The prognostic role of IL-1B/IL-1RN genotypes was investigated in patients with relapsed and metastatic gastric cancer treated with palliative chemotherapy. PATIENTS AND METHODS: Before starting palliative chemotherapy, 123 prospectively enrolled patients supplied peripheral-blood samples for DNA extraction. Survival data were analyzed according to IL-1RN/IL-1B genotypes. RESULTS: Forty-two patients showed wild-type genotypes (IL-1RNlong/long, IL-1B-511C/C, and IL-1B-31T/T; group A). Forty-five patients showed the IL-1RN2 polymorphism, with wild-type IL-1B genotypes in seven patients and with IL-1B-511C/T and/or IL-1B-31T/C polymorphisms in 38 patients (group B). The remaining 36 patients demonstrated wild-type IL-1RN, with IL-1B-511C/T and/or IL-1B-31T/C polymorphisms (group C). In group A and B patients, the median progression-free survival (PFS) was 25 and 26 weeks, respectively, and median overall survival (OS) was 42 and 43 weeks, respectively. Group C patients showed worse PFS (median, 16 weeks) and OS (median, 28 weeks) than group A (P = .006 for PFS; P = .0001 for OS) and group B patients (P = .01 for PFS; P = .0001 for OS). The long/T/C haplotype was overrepresented in patients with shortened PFS (P = .001) and OS (P = .0005). CONCLUSION: In patients with advanced gastric cancer, IL-1B polymorphisms showed adverse prognostic influence when coupled with wild-type IL-1RN genotype. These findings deserve further investigation for potential anticancer activity of recombinant IL-RN.     

Clinical characteristics of a large cohort of patients with narcolepsy candidate for pitolisant: a cross-sectional study from the Italian PASS Wakix® Cohort

Neurological Sciences - Narcolepsy is a chronic and rare hypersomnia of central origin characterized by excessive daytime sleepiness and a complex array of symptoms as well as by several medical...