Detection of COL1A1 -PDGFB fusion transcripts and platelet-derived growth factor α and β receptors in giant cell fibroblastoma of the postsacrococcygeal region

We describe a 2-year-old girl with recurrent giant cell fibroblastoma (GCF) of the postsacrococcygeal region. Both the initial and recurrent tumours contained solid and angiectoid areas. The former was composed of loosely arranged wavy spindle cells and giant cells with a well-vascularized myxoid to collagenous stroma. The angiectoid spaces were often lined by multinucleated giant cells. Immunohistochemically, the tumour cells and small vessels in the tumour tissue were positive for platelet-derived growth factor (PDGF) alpha and beta receptors. Molecular analysis revealed fusion of collagen type Ialpha1 exon 26 with PDGF-B chain exon 2 that induced unscheduled production of PDGF-BB. These findings suggest that PDGF and its receptors significantly contribute to the development of GCF in both an autocrine and a paracrine manner.

Pyridoxine-induced photosensitivity and hypophosphatasia

We describe a case of photosensitivity due to pyridoxine hydrochloride (vitamin B(6)) in a heterozygote of hypophosphatasia. Photopatch tests using pyridoxine hydrochloride and pyridoxal 5'-phosphate, compounds referred to as vitamin B(6), with ultraviolet light A irradiation were positive. Laboratory examination showed low serum alkaline phosphatase. Tissue-nonspecific alkaline phosphatase exon amplification from DNA of the patient's lymphocytes detected deletion 1154-1156 hypophosphatasia mutation, indicating that this patient was diagnosed to be a heterozygote of hypophosphatasia. The seric pyridoxal 5'-phosphate level of this patient with hypophosphatasia was higher than in normals. Furthermore, after oral administration of vitamin B(6) this level increased greatly and long-lastingly, and this might be related to the low level of alkaline phosphatase in this patient. Photosensitivity in this patient may have been caused by abnormal metabolism of vitamin B(6) under the hypophosphatic condition.

Crystal structure of human serum albumin at 2.5 A resolution

A new triclinic crystal form of human serum albumin (HSA), derived either from pool plasma (pHSA) or from a Pichia pastoris expression system (rHSA), was obtained from polyethylene glycol 4000 solution. Three-dimensional structures of pHSA and rHSA were determined at 2.5 A resolution from the new triclinic crystal form by molecular replacement, using atomic coordinates derived from a multiple isomorphous replacement work with a known tetragonal crystal form. The structures of pHSA and rHSA are virtually identical, with an r.m. s. deviation of 0.24 A for all Calpha atoms. The two HSA molecules involved in the asymmetric unit are related by a strict local twofold symmetry such that the Calpha atoms of the two molecules can be superimposed with an r.m.s. deviation of 0.28 A in pHSA. Cys34 is the only cysteine with a free sulfhydryl group which does not participate in a disulfide linkage with any external ligand. Domains II and III both have a pocket formed mostly of hydrophobic and positively charged residues and in which a very wide range of compounds may be accommodated. Three tentative binding sites for long-chain fatty acids, each with different surroundings, are located at the surface of each domain.

Crystal structures of L201A mutant of D-amino acid aminotransferase at 2.0 A resolution: implication of the structural role of Leu201 in transamination

The leucine-to-alanine mutation at residue 201 of D-amino acid aminotransferase provides a unique enzyme which gradually loses its activity while catalyzing the normal transamination; the co-enzyme form is converted from pyridoxal 5'-phosphate to pyridoxamine 5'-phosphate upon the inactivation [Kishimoto,K., Yoshimura,T., Esaki,N., Sugio,S., Manning,J.M. and Soda,K. (1995) J. Biochem., 117, 691-696]. Crystal structures of both co-enzyme forms of the mutant enzyme have been determined at 2.0 A resolution: they are virtually identical, and are quite similar to that of the wild-type enzyme. Significant differences in both forms of the mutant are localized only on the bound co-enzyme, the side chains of Lys145 and Tyr31, and a water molecule sitting on the putative substrate binding site. Detailed comparisons of the structures of the mutant, together with that of the pyridoxamine-5'-phosphate form of the wild-type enzyme, imply that Leu201 would play a crucial role in the transamination reaction by keeping the pyridoxyl ring in the proper location without disturbing its oscillating motion, although the residue seems to not be especially important for the structural integrity of the enzyme.

X-ray crystal structure of a dipeptide-chymotrypsin complex in an inhibitory interaction

The dipeptide D-leucyl-L-phenylalanyl p-fluorobenzylamide (D-Leu-Phe-NH-BzlF) inhibits chymotrypsin strongly in a competitive manner with the Ki value of 0.61 microM [Shimohigashi, Y., Maeda, I., Nose, T., Ikesue, K., Sakamoto, H., Ogawa, T., Ide, Y., Kawahara, M., Nezu, T., Terada, Y., Kawano, K. & Ohno, M. (1996) J. Chem. Soc. Perkin Trans. 1, 2479-2485]. The structure/activity studies have suggested a unique inhibitory conformation, in which the C-terminal benzyl group fits the chymotrypsin S1 site and the hydrophobic core constructed by the side chains of D-Leu-Phe fits the S2 or S1' site. To verify this assumption, the molecular structure of the complex between the dipeptide and gamma-chymotrypsin has been determined crystallographically. Gamma-chymotrypsin itself was first crystallized and refined at 1.6-A resolution. The refined structure was virtually identical to the conformation reported and the electron density at the active site was interpreted as a pentapeptide Thr-Pro-Gly-Val-Tyr derived from autolysis of the enzyme (residues 224-228). The chymotrypsin-dipeptide complex was obtained by soaking the crystals of gamma-chymotrypsin in a solution saturated with the dipeptide inhibitor. The crystal structure of the complex has been refined at 1.8-A resolution to a crystallographic R-factor of 18.1%. The structure of gamma-chymotrypsin in the complex agreed fairly well with that of gamma-chymotrypsin per se with a rmsd of 0.13 A for all the C alpha carbons. Two inhibitor molecules were assigned in an asymmetric unit, i.e. one in the active site and the other at the interface of two symmetry-related enzyme molecules. In both sites dipeptides adopted very similar folded conformations, in which side chains of D-Leu-Phe are spatially proximal. In the active site where the binding of dipeptide was judged to be a direct cause of inhibition, C-terminal p-fluorobenzylamide group of the dipeptide, NH-BzlF, was found in the S1 hydrophobic pocket. At the bottom of this pocket, the p-fluorine atom hydrogen bonded with a water molecule, probably to enhance the inhibitory activity. The stereospecific interaction of R and S isomers of the dipeptide with C-terminal NH-C*H(CH3)-C6H5 was well explained by the space available for methyl replacement in the complex. The hydrophobic core constructed by side chains of D-Leu-Phe was found at the broad S2 site. Interestingly, a novel interaction was found between the inhibitor Phe residue and chymotrypsin His57, the phenyl of Phe and the imidazole of His being in a pi-pi stacking interaction at a distance 3.75 A.

[Improved quality of life (QOL) in terminal renal carcinoma patients through home nurse visitation: some considerations]

Ours is a general hospital administered directly by the government. There are 585 beds and some 1,200 outpatients on average per day. Visits by home nurses began in September of 1990, and beginning in April of 1994 a home nursing department has been in place at the Community Medical Center. There are 5 persons in charge of the visits. Home visits are paid to 40 patients at present on an ongoing basis. In recent years, malignant diseases have been increasing, and there has been much discussion devoted to the quality of life (QOL) of the patients. In 1994, 15 of the 60 patients visited had malignant diseases. Presently, a 63-year-old female patient with terminal kidney cancer is receiving HPN. Thanks to home nursing visits, she has been able to be discharged. This patient had been receiving home nursing visits from December 21, 1993 until June 20 of 1994 at the rate of 2 visits per month. The person in charge gave guidance for HPN management, and the patient began to regain her pre-hospitalization life and a sense of her role in her family and society. As a result, though she had not actively fought the disease while in the hospital, she gained confidence with the HPN, and with her husband's help, she became a Culture School teacher, resumed her role in society and found her life meaningful. Since there were limits to her husband's ability to care for her, she agreed to enter the hospital again, but was able to continue meaningful life at home for 6 months with assistance from a caregiver, and thus achieved a high QOL.

Aromatase inhibitors: synthesis, biological activity, and structure of 1,2-imidazolylmethylcyclopentanol derivatives

Two series of 1,2-disubstituted imidazolylmethylcyclopentanol derivatives (5a-d, 10a-d) were prepared by using easily available methyl 2-oxocyclopentanecarboxylate as the starting material. Evaluation of the aromatase inhibitory activities in vitro was performed. Their activities were compared with those of a steroidal aromatase inhibitor, Formestane, and a non-steroidal inhibitor, Fadrozole. Among these compounds, the aromatase inhibitory activities of 5d, 10a, 10b, 10c, 11a, 15a, and 15b were more potent than Formestane. One compound, 1-(4-chlorobenzyl)-cis-2-(1H-imidazol-1-ylmethyl)cyclopentanol+ ++ (10a) was in particular identified as a potent aromatase inhibitor in vitro, exhibiting an IC50 value of 4 x 10(-8)M. The enantiomers of 10a were separated, and their absolute configuration were determined by X-ray crystallography.