Balloon Cell Malignant Melanoma in a Young Female: A Case Report and Review of the Literature

Balloon cell malignant melanoma (BCMM) is a very rare malignant melanoma subtype. The clinical appearance of BCMM varies; it may be nodular, ulcerated, polypoid, papillomatous and often non-pigmented. The tumor cells histologically appear large, polygonal or round and contain abundant granular or vacuolated cytoplasm. We herein report the case of a 32-year-old female who presented with a focal eccentric pigmented mass in the left lumbar region of 15 mm in diameter that had been present for several years. She underwent tumor excision. The histopathological analysis showed epithelioid melanocytes with clear cytoplasm. An immunohistochemical analysis revealed that the cells were positive for HMB-45 and S-100 protein and negative for cytokeratin. The balloon cell component stained negative for Fontana-Masson. A month later, the patient underwent excision of the bilateral inguinal lymph nodes and metastatic BCMM was revealed. The lymph node metastases showed the complete replacement of lymph nodes by balloon cells. A diagnosis of BCMM (Breslow depth 10 mm, Clark level V) without ulcer was rendered. Staining with Ki-67 was positive in almost 44% of the balloon cells

Microbial Populations Responsive to Denitrification-Inducing Conditions in Rice Paddy Soil, as Revealed by Comparative 16S rRNA Gene Analysis▿ †

Rice paddy soil has been shown to have strong denitrifying activity. However, the microbial populations responsible for nitrate respiration and denitrification have not been well characterized. In this study, we performed a clone library analysis of >1,000 clones of the nearly full-length 16S rRNA gene to characterize bacterial community structure in rice paddy soil. We also identified potential key players in nitrate respiration and denitrification by comparing the community structures of soils with strong denitrifying activity to those of soils without denitrifying activity. Clone library analysis showed that bacteria belonging to the phylum Firmicutes, including a unique Symbiobacterium clade, dominated the clones obtained in this study. Using the template match method, several operational taxonomic units (OTUs), most belonging to the orders Burkholderiales and Rhodocyclales, were identified as OTUs that were specifically enriched in the sample with strong denitrifying activity. Almost one-half of these OTUs were classified in the genus Herbaspirillum and appeared >10-fold more frequently in the soils with strong denitrifying activity than in the soils without denitrifying activity. Therefore, OTUs related to Herbaspirillum are potential key players in nitrate respiration and denitrification under the conditions used

Regulation of the Rate of Dinucleation of a Monocopper(I) Complex Containing Bipyrimidine Rotary Units by Restricted Double Pyrimidine Rotation

New copper­(I) complexes with coordinated 2-(4′-methyl)­pyrimidinyl moieties were fabricated, and the isomerism of their pyrimidine ring linkage was investigated. The ligands bis­[2-(diphenylphosphino)­phenyl] ether (DPEPhos) and 4,4′-dimethyl-2,2′-bipyrimidine (dmbpm) were used to synthesize a heteroleptic copper­(I) complex, [Cu^I(DPEPhos)­(dmbpm)]·BF₄ (<b>1</b>·BF₄), and a dinuclear copper­(I) complex, [(Cu^I)₂(DPEPhos)₂(μ-dmbmp)]­(BF₄)₂ [<b>2</b>·(BF₄)₂]. The X-ray crystallographic structures, UV–vis absorption spectra, and luminescence properties of the complexes were analyzed. The thermodynamic and kinetic aspects of the isomerism of <b>1</b>·BF₄ were examined by variable-temperature NMR. Double pyrimidine ring rotation was found to be restricted sterically by the bulky DPEPhos ligands. This limited the number of the possible isomers: <b>1</b>·BF₄ showed only isomers with either one (<i>io</i> isomer) or both (<i>oo</i> isomer) of the two methyl groups positioned away from the copper center, while dinuclear <b>2</b>·(BF₄)₂ was only found as a symmetric (<i>io</i>–<i>io</i>) isomer, with each of the two methyl groups positioned toward different copper centers. The addition of [Cu­(MeCN)₂(DPEPhos)] (<b>3</b>·BF₄) allowed both isomers of <b>1</b>·BF₄ to form <b>2</b>·(BF₄)₂, although at different rates and via different pathways, which were analyzed using time-dependent UV–vis spectroscopy. The <i>io</i> isomer dinucleated more quickly than the <i>oo</i> isomer owing to it being able to form <b>2</b>·(BF₄)₂ (i) without bond dissociation and (ii) without a sterically congested <i>ii</i> configuration around the copper center. In contrast, <i>oo</i>-<b>1</b>·BF₄ required (i) recombination of the bipyrimidine coordination bonds or (ii) formation of a product with higher thermodynamic energy, unsymmetric (<i>ii</i>–<i>oo</i>) <b>2</b>·(BF₄)₂. These findings are interpreted as demonstrating a novel kinetic property: a conversion rate determined by pyrimidine ring inversion