The small molecule inhibitor G6 significantly reduces bone marrow fibrosis and the mutant burden in a mouse model of Jak2-mediated myelofibrosis.

Philadelphia chromosome-negative myeloproliferative neoplasms, including polycythemia vera, essential thrombocytosis, and myelofibrosis, are disorders characterized by abnormal hematopoiesis. Among these myeloproliferative neoplasms, myelofibrosis has the most unfavorable prognosis. Furthermore, currently available therapies for myelofibrosis have little to no efficacy in the bone marrow and hence, are palliative. We recently developed a Janus kinase 2 (Jak2) small molecule inhibitor called G6 and found that it exhibits marked efficacy in a xenograft model of Jak2-V617F-mediated hyperplasia and a transgenic mouse model of Jak2-V617F-mediated polycythemia vera/essential thrombocytosis. However, its efficacy in Jak2-mediated myelofibrosis has not previously been examined. Here, we hypothesized that G6 would be efficacious in Jak2-V617F-mediated myelofibrosis. To test this, mice expressing the human Jak2-V617F cDNA under the control of the vav promoter were administered G6 or vehicle control solution, and efficacy was determined by measuring parameters within the peripheral blood, liver, spleen, and bone marrow. We found that G6 significantly reduced extramedullary hematopoiesis in the liver and splenomegaly. In the bone marrow, G6 significantly reduced pathogenic Jak/STAT signaling by 53%, megakaryocytic hyperplasia by 70%, and the Jak2 mutant burden by 68%. Furthermore, G6 significantly improved the myeloid to erythroid ratio and significantly reversed the myelofibrosis. Collectively, these results indicate that G6 is efficacious in Jak2-V617F-mediated myelofibrosis, and given its bone marrow efficacy, it may alter the natural history of this disease.

Short-term response of mitomycin C on the human rectus muscle following strabismus surgery: histological, ultrastructural, and biomechanical evaluation.

This study investigated the inflammatory effect of intraoperative mitomycin C (MMC) on adhesion reformation in human rectus muscles. Ten consecutive patients who underwent medial rectus resection had their postoperative rectus muscles divided into two groups: control group (n = 10) and MMC group (n = 10). In the MMC group, the muscle was soaked for 2 min with MMC, prepared as a 0.2 mg/mL (0.02%) solution. The 0.02% MMC reactions were examined using histological analysis with hematoxylin-eosin (inflammatory response) and Masson's trichrome (collagen fibrils), immunoreactivities of cyclooxygenase-II (inflammatory response), and collagen type I and III, scanning electron microscopy analysis to quantify the diameter and D-periodicity of collagen fibrils, and atomic force microscopy analysis to quantify the diameter, D-periodicity, and adhesion force of collagen fibrils. The rectus muscles treated with 0.02% MMC showed a significantly increased inflammatory response (p < 0.05), increased collagen density (p < 0.0001), increased fibril diameter (p < 0.001 or p < 0.05), and decreased fibril adhesion force (p < 0.005) compared to the rectus muscles in the control group. MMC simultaneously caused an inflammatory response as well as nanostructural and biomechanical property changes in the collagen fibril network.

Prostate carcinogenesis induced by N-methyl-N-nitrosourea (mnu) in gerbils: histopathological diagnosis and potential invasiveness mediated by extracellular matrix components.

In the present study prostate lesions were induced in gerbils (Meriones unguiculatus) treated with a single N-methyl-N-nitrosourea (MNU) dose; thus, the incidence, latency and histology of these lesions were evaluated. Fibrillar elements of the extracellular matrix associated with microinvasive sites were also investigated. Animals were divided into 5 groups, including 2 control groups: (1) remained untreated; (2) received the corn oil vehicle (vehicle, 0.1 ml/application) and three different tumor induction regimens: (1) received MNU (30 mg/kg) and weekly testosterone (2 mg/kg) (MNU+testosterone); (2) received only MNU (30 mg/kg); (3) received weekly testosterone doses (2 mg/kg). After 3 and 6 months the animals were dissected and the prostates were evaluated morphologically, immunohistochemically and quantitatively. MNU plus androgen contributed to the development of prostatic intraepithelial neoplasia, microinvasive carcinoma and adenocarcinoma in gerbil prostate. However, these lesions occurred earlier in time in groups that received MNU and androgen compared to control animals as they over time also developed to a high extent microinvasive lesions. Cytochemistry and immunohistochemistry showed that these injuries were commonly associated with inflammatory cells whereas the epithelial cells presented proliferative activity. The alpha-methylacyl-CoA racemase (AMACR) expression in prostate cancer cells facilitated diagnosis of gerbil lesions. Testosterone, MNU and MNU+testosterone showed an increased epithelial volume, although the secretory activity was significantly suppressed mainly at neoplastic foci. In the prostatic stroma, reticular fibers increased significantly in MNU, MNU+testosterone and among the lesions found in these groups, while collagen fibers decreased at neoplastic sites. The disruption of the basement membrane was proven at malignant sites by ultrastructural analysis and type IV collagen and laminin degradation. The prostate carcinogenesis mediated by MNU and androgen stimulated the emergence of proliferative lesions in gerbils after short periods and showed the importance of a dynamic remodeling of stromal components for cellular invasiveness.

Confluent and reticulated papillomatosis (Gougerot-Carteaud) successfully treated with tacalcitol.

Confluent and reticulated papillomatosis (CRP) is a rare dermatosis of unknown aetiology whose relationship to Malassezia furfur is still debated. Antifungal agents, antibiotics, retinoids, and, more recently, calcipotriol have been successfully used as treatment. The authors report on a 14-year-old female with confluent and reticulated papillomatosis in whom M. furfur was found. Anti-fungal therapy eliminated the fungus, but did not achieve the disappearance of the lesions. Further treatment with tacalcitol was successful, supporting the theory that CRP might be a disorder of keratinization. To the authors' knowledge, this is the first patient treated with tacalcitol for this entity.

Additional histopathologic examination of the lungs from a 3-month inhalation toxicity study with multiwall carbon nanotubes in rats.

For hazard assessment of multiwalled carbon nanotubes (MWCNTs), a 90-day inhalation toxicity study has been performed with Nanocyl NC 7000 in accordance with OECD 413 test guideline. MWCNTs produced no systemic toxicity. However, increased lung weights, multifocal granulomatous inflammation, diffuse histiocytic and neutrophilic infiltrates, and intra-alveolar lipoproteinosis were observed in lung and lung-associated lymph nodes at 0.5 and 2.5mg/m(3). Additional investigations of the lungs were performed, including special stains for examination of connective tissue, and electron microscopy was performed to determine the location of the MWCNTs. The alveolar walls revealed no increase of collagen fibers, whereas within the microgranulomas a slight increase of collagen fibers was observed. The pleura did not reveal any increase in collagen fibers. Only a slight increase in reticulin fibers in the alveolar walls in animals of the 0.5 and 2.5mg/m(3) concentration group was noted. In the 0.1mg/m(3) group, the only animal revealing minimal granulomas exhibited a minimal increase in collagen within the granuloma. No increase in reticulin was observed. Electron microscopy demonstrated entangled MWCNTs within alveolar macrophages. Occasionally electron dense particles/detritus were observed within membrane-bound vesicles (interpreted as phagosomes), which could represent degraded MWCNTs. If so, MWCNTs were degradable by alveolar macrophages and not persistent within the lung. Inhalation of MWCNTs caused granulomatous inflammation within the lung parenchyma but not the pleura in any of the concentration groups. Thus, there are some similarities to effects caused by inhaled asbestos, but the hallmark effects, namely pleural inflammation and/or fibrosis leading to mesotheliomas, are absent.

Morphology of the bone marrow, spleen and liver during hematopoietic cell mobilization with cyclophosphamide in mice.

Cyclophosphamide (CY), the agent with cytoreductive activity, is widely exploited in cancer chemotherapy, and can be used alone or in combination with various cytokines and growth factors to stimulate the egress of hematopoietic stem/progenitor cells (HSPC) from the BM compartment. The aim of the present study was to exam the morphology and ultrastructure of the bone marrow, spleen and liver of mice injected intraperitoneally with a single dose of cyclophosphamide (200 mg/kg bw) and the localization of cells expressing markers of early hematopoietic cells in studied organs and the peripheral blood. We observed that the CY-induced morphological changes in the BM and spleen were reconstructed on day 4. of experiment, and the spleen was repopulated by HSPC on the 6th day. In this time, the highest number of c-Kit-R-positive cells was determined by flow cytometry in the peripheral blood. The results confirmed, that the egress of HSPC from the bone marrow into the peripheral blood was delayed compared to mice treated with G-CSF or GCS-F plus CY.

Delayed reduction in left ventricular function following treatment of non-Hodgkin's lymphoma with chemotherapy and rituximab, unrelated to acute infusion reaction.

We report 3 cases of reduced cardiac function with complications in non-Hodgkin's lymphoma patients who were treated with rituximab. Patients experienced reduced cardiac functions after the administration of rituximab; there was no evidence of any preceding infusion reactions. Reticulin fiber was observed diffusely in cardiac muscles. Transforming growth factor-beta levels were elevated after the administration of rituximab. We believe that continuous elevation of transforming growth factor-beta may promote the growth of reticulin fiber in cardiac muscles. Reduction in cardiac functions is a severe complication that must be considered when rituximab is administered.

The effects of enrofloxacin on decorin and glycosaminoglycans in avian tendon cell cultures.

Tendonitis and tendon rupture have been reported to occur during or following therapy with fluoroquinolone antibiotics. Though the pathogenesis is unknown, several studies suggest that fluoroquinolone antibiotics alter proteoglycan content in soft tissues, including tendons, and thereby alter collagen fibrillogenesis. To better understand the mechanism of action of fluoroquinolones, we studied the effects of enrofloxacin, a widely used fluoroquinolone in veterinary medicine, on avian tendon cell cultures established from gastrocnemius tendons from 18-day-old chicken embryos. We found that cell proliferation was progressively inhibited with increasing concentrations of enrofloxacin. This was accompanied by changes in morphology, extracellular matrix content and collagen fibril formation as detected by electron microscopy. We also observed a 35% decrease in the content of total monosaccharides in enrofloxacin-treated cells. The ratio of individual monosaccharides was also altered in enrofloxacin-treated cells. Enrofloxacin also induced the synthesis of small amounts of keratan sulfate in tendon cells. Moreover we observed enrofloxacin-induced changes in glycosylation of decorin, the most abundant tendon proteoglycan, resulting in the emergence of multiple lower molecular bands that were identifiable as decorin after chondroitinase ABC and N-glycanase treatment of extracts from enrofloxacin-treated cells. Medium conditioned by enrofloxacin-treated cells contained less decorin than did medium conditioned by control cells. We hypothesize that enrofloxacin induces either changes in the number of N-linked oligosaccharides attached to the core protein of decorin or changes in decorin degradation process. In conclusion, our data suggest that enrofloxacin affects cell proliferation and extracellular matrix through changes in glycosylation.

Airway subepithelial fibrosis in a murine model of atopic asthma: suppression by dexamethasone or anti-interleukin-5 antibody.

Fibrosis in the reticular layer beneath the epithelial basement membrane is a feature of airway remodeling in human asthma. We previously reported the presence of subepithelial fibrosis (SEF) in a disease model of atopic asthma in which mice were sensitized and intratracheally challenged with ovalbumin (OVA) (Blyth and colleagues, Am. J. Respir. Cell Mol. Biol. 1996;14:425-438). Here, we describe further studies to quantify the degree of SEF after its induction by repeated exposure of the airways to allergen. The amount of subepithelial reticulin in the airways of animals challenged three times with 80 microg OVA was typically increased 1. 4-fold. The increased amount of reticulin showed no reduction after a 50-d period after the third allergen challenge. A reduction in SEF was achieved by daily treatment with dexamethasone (DEX) for 8 d during the allergen challenge period, or by treatment with anti-interleukin-5 antibody (TRFK5) at the time of allergen challenge. Postchallenge treatment with DEX for 15 d resulted in significant resolution of previously established SEF. Severe nonallergic inflammation during repeated exposure of airways to lipopolysaccharide did not induce SEF. The results indicate that development of SEF is associated with eosinophil infiltration into airways, and may occur only when the inflammatory stimulus is allergic in nature.