Transition and post-transition metal ions in borate glasses: Borate ligand speciation, cluster formation, and their effect on glass transition and mechanical properties.

A series of transition and post-transition metal ion (Mn, Cu, Zn, Pb, Bi) binary borate glasses was studied with special consideration of the cations impact on the borate structure, the cations cross-linking capacity, and more generally, structure-property correlations. Infrared (IR) and Raman spectroscopies were used for the structural characterization. These complementary techniques are sensitive to the short-range order as in the differentiation of tetrahedral and trigonal borate units or regarding the number of non-bridging oxygen ions per unit. Moreover, vibrational spectroscopy is also sensitive to the intermediate-range order and to the presence of superstructural units, such as rings and chains, or the combination of rings. In order to clarify band assignments for the various borate entities, examples are given from pure vitreous B2O3 to meta-, pyro-, ortho-, and even overmodified borate glass compositions. For binary metaborate glasses, the impact of the modifier cation on the borate speciation is shown. High field strength cations such as Zn2+ enhance the disproportionation of metaborate to polyborate and pyroborate units. Pb2+ and Bi3+ induce cluster formation, resulting in PbOn- and BiOn-pseudophases. Both lead and bismuth borate glasses show also a tendency to stabilize very large superstructural units in the form of diborate polyanions. Far-IR spectra reflect on the bonding states of modifier cations in glasses. The frequency of the measured cation-site vibration band was used to obtain the average force constant for the metal-oxygen bonding, FM-O. A linear correlation between glass transition temperature (Tg) and FM-O was shown for the metaborate glass series. The mechanical properties of the glasses also correlate with the force constant FM-O, though for cations of similar force constant the fraction of tetrahedral borate units (N4) strongly affects the thermal and mechanical properties. For paramagnetic Cu- and Mn-borate glasses, N4 was determined from the IR spectra after deducing the relative absorption coefficient of boron tetrahedral versus boron trigonal units, α = α4/α3, using NMR literature data of the diamagnetic glasses.

Hepatic arterial infusion chemotherapy with cisplatin before radical local treatment of early hepatocellular carcinoma (JIS score 0/1) improves survival.

BACKGROUND: It has not yet been determined whether hepatic arterial infusion (HAI) chemotherapy improves survival in patients with early hepatocellular carcinoma (HCC). We evaluated the effectiveness of HAI with high-concentration cisplatin (DDP-H) for the treatment of HCC by comparing outcomes between patients who received HAI with DDP-H before radical local treatment of early-stage HCC [Japan Integrated Staging (JIS) score 0/1] and patients who did not receive HAI chemotherapy. PATIENTS AND METHODS: Survival was analyzed in 114 patients with early-stage HCC who underwent radical local treatment. The patients were divided into two groups: a HAI group (n = 79) who received DDP-H infusion into the whole liver via the proper hepatic artery, and a non-HAI group (n = 35) who did not receive HAI chemotherapy. RESULTS: The cumulative survival rates at 1, 3, and 5 years were 77.4%, 69.2%, and 55.3% in the non-HAI group and 97.4%, 87.0%, and 84.4% in the HAI group, respectively. Survival time prolonged significantly in the HAI group compared with the non-HAI group (log-rank test: P = 0.023; generalized Wilcoxon test: P = 0.012) Multivariate analysis using the Cox proportional hazards model identified HAI with DDP-H as the most important factor affecting survival. CONCLUSIONS: Whole-liver HAI with DDP-H before radical local treatment can improve the prognosis of patients with early-stage HCC.

Increased systemic inflammatory interleukin-1ß and interleukin-6 during agitation as predictors of Alzheimer's disease.

OBJECTS: Identification of biomarkers for Alzheimer's disease (AD) is important for its early diagnosis and prevention and a key in advancing our understanding of its pathophysiology. The aim of this study was to determine whether systemic inflammatory interleukin-1ß (IL-1ß) and interleukin-6 (IL-6) as well as hypertension (HT), diabetes mellitus (DM), and body mass index (BMI) are predictors of AD. METHODS: We performed a 10-year follow-up study on 133 elderly who were institutionalized in a nursing home. The associations of IL-1ß and IL-6 at both rest and agitation, as well as HT, DM, and BMI at baseline, were analyzed with the incidences of vascular dementia (VD) and AD during a 10-year follow-up period. RESULTS: The Kaplan-Meier method with log-rank test and Cox regression analyses for the total of 133 subjects showed significantly higher incidences of both VD and AD in subjects with DM or HT at baseline. Resting IL-1ß or IL-6 value, or agitation score, was not significantly associated with the subsequent development of VD or AD. The analyses of 40 subjects who had shown agitation at least once in the previous 3 months demonstrated that IL-1ß and IL-6 values at the agitation stage were significantly associated with AD, but not with VD. CONCLUSION: Our results indicate that systemic inflammatory IL-1ß and IL-6 at the agitation stage are risk factors for the development of AD, but not VD. Inflammatory mechanisms for AD seem to be causal and specific to the development of AD.

Association between altered systemic inflammatory interleukin-1beta and natural killer cell activity and subsequently agitation in patients with Alzheimer disease.

OBJECTIVE: Alzheimer's disease (AD) is a neurodegenerative disorder that is the most common cause of dementia in the elderly and is frequently accompanied by emotional disorder, including agitation. Although evidence of neuroendocrine immune and inflammatory functions during emotional changes has been accumulated, the pathogenic mechanisms in the development of agitation accompanied by AD remain to be elucidated. METHODS: To clarify the involvement of neuroendocrine and immune and inflammatory systems in agitation in AD, we examined agitation levels, circadian rhythms of behavior, cortisol, interleukin-1beta (IL-1beta), and natural killer cell activity (NKCA) in controls without dementia and 16 AD patients who were recognized to be easily agitated in their nursing homes. These behavioral and blood indicators were assessed according to the progress of the stage of agitation in 16 AD patients (stable, pre-agitation, and agitation stages). RESULTS: Elevations in night behavior and blood cortisol, IL-1beta and an reduced blood NKCA level in the evening were observed not only in the agitation stage, but also when stable in AD patients as compared to the control. Increased IL-1beta and decreased NKCA occurred in both the morning and evening in pre-agitation and agitation stages in AD. CONCLUSIONS: The increased IL-1beta and decreased NKCA with the progress of agitation in AD suggest that inflammation produces agitation and aggravates AD.

Impact of technically qualified surgeons on laparoscopic colorectal resection outcomes: results of a propensity score-matching analysis.

BACKGROUND: The Endoscopic Surgical Skill Qualification System (ESSQS) was introduced in Japan to improve the quality of laparoscopic surgery. This cohort study investigated the short- and long-term postoperative outcomes of colorectal cancer laparoscopic procedures performed by or with qualified surgeons compared with outcomes for unqualified surgeons. METHODS: All laparoscopic colorectal resections performed from 2010 to 2013 in 11 Japanese hospitals were reviewed retrospectively. The procedures were categorized as performed by surgeons with or without the ESSQS qualification and patients' clinical, pathological and surgical features were used to match subgroups using propensity scoring. Outcome measures included postoperative and long-term results. RESULTS: Overall, 1428 procedures were analysed; 586 procedures were performed with ESSQS-qualified surgeons and 842 were done by ESSQS-unqualified surgeons. Upon matching, two cohorts of 426 patients were selected for comparison of short-term results. A prevalence of rectal resection (50·3 versus 40·5 per cent; P < 0·001) and shorter duration of surgery (230 versus 238 min; P = 0·045) was reported for the ESSQS group. Intraoperative and postoperative complication and reoperation rates were significantly lower in the ESSQS group than in the non-ESSQS group (1·2 versus 3·6 per cent, P = 0·014; 4·6 versus 7·5 per cent, P = 0·025; 1·9 versus 3·9 per cent, P = 0·023, respectively). These findings were confirmed after propensity score matching. Cox regression analysis found that non-attendance of ESSQS-qualified surgeons (hazard ratio 12·30, 95 per cent c.i. 1·28 to 119·10; P = 0·038) was independently associated with local recurrence in patients with stage II disease. CONCLUSION: Laparoscopic colorectal procedures performed with ESSQS-qualified surgeons showed improved postoperative results. Further studies are needed to investigate the impact of the qualification on long-term oncological outcomes.

ANTECEDENTES: El Sistema de Certificación de Habilidades Quirúrgicas Endoscópicas (Endoscopic Surgical Skill Qualification System, ESSQS) fue introducido en Japón para mejorar la calidad de la cirugía laparoscópica. En este estudio de cohortes se investigaron los resultados postoperatorios a corto y a largo plazo de las intervenciones laparoscópicas de cáncer colorrectal realizadas por o con la asistencia de cirujanos con certificación en comparación con cirujanos no certificados. MÉTODOS: Todas las resecciones colorrectales laparoscópicas realizadas entre 2010 y 2013 en 11 hospitales japoneses fueron revisadas retrospectivamente. Los procedimientos se clasificaron en función de si habían sido realizados por cirujanos con o sin certificación del ESSQS, y las características clínicas, patológicas y quirúrgicas de los pacientes se utilizaron para emparejar los subgrupos mediante puntuaciones de propensión. Las variables de resultado incluyeron los resultados postoperatorios y a largo plazo RESULTADOS: En total se analizaron 1.428 procedimientos, incluyendo 586 y 842 procedimientos realizados con y sin cirujanos certificados por ESSQS, respectivamente. Tras el emparejamiento, se seleccionaron dos cohortes de 426 pacientes para la comparación de resultados a corto plazo. Se observó una mayor prevalencia de resecciones rectales (50,3% versus 40,1%, P = 0,0001) y un tiempo quirúrgico más corto (230 versus 238 min, P = 0,04) en el grupo ESSQS. Las tasas de complicaciones intra- y postoperatorias y de reoperaciones fueron significativamente más bajas en el grupo ESSQS que en el grupo no ESSQS (1,2%, 4,6% y 1,9% versus 3,6%, 7,5% y 3,9%, P = 0,01; 0,03, y 0,02, respectivamente). Estos hallazgos se confirmaron tras el análisis de emparejamiento por puntaje de propensión. El análisis de regresión de Cox mostró que la no participación de cirujanos certificados con ESSQS (razón de oportunidades, odds ratio, OR 12,3; i.c. del 95%, 1,28-119,1; P = 0,03) se asoció independientemente con la recidiva local en los casos en estadio II. CONCLUSIÓN: Los procedimientos colorrectales laparoscópicos realizados por cirujanos certificados por ESSQS presentaron mejores resultados postoperatorios. Son necesarios más estudios para determinar el impacto de la certificación en los resultados oncológicos a largo plazo.

ARR1, a transcription factor for genes immediately responsive to cytokinins.

Cytokinins are a class of phytohormones involved in various physiological events of plants. The Arabidopsis sensor histidine kinase CRE1 was recently reported to be a cytokinin receptor. We used a steroid-inducible system to show that the transcription factor-type response regulator ARR1 directs transcriptional activation of the ARR6 gene, which responds to cytokinins without de novo protein synthesis. This fact, together with characteristics of ARR1-overexpressing plants and arr1 mutant plants, indicates that the phosphorelay to ARR1, probably from CRE1, constitutes an intracellular signal transduction occurring immediately after cytokinin perception.

Micro-CT analysis of alveolar bone healing using a rat experimental model of critical-size defects.

OBJECTIVE: This study was designed to establish a rat model of a critical size alveolar bone defect. MATERIALS AND METHODS: Standardized buccal or mesiobuccal alveolar bone defects were made around the right first mandibular molar of 12-week-old rats, and the left was used as a control. Alveolar bone healing was examined quantitatively by three-dimensional micro-computed tomographic imaging. Bone matrix production of osteoblasts and osteocytes during repair of alveolar bone defects was examined with in situ hybridization for type I collagen. RESULTS: Buccal defects were repaired significantly and the volume decreased by 88.3% in week 24, whereas mesiobuccal defects were repaired little. Osteoblasts and osteocytes expressed type I collagen in both defects in week 3 but showed little expression by week 6 and thereafter, leaving the mesiobuccal defects largely unrepaired. CONCLUSION: The mesiobuccal defect is a critical-size defect that is not ultimately repaired with bone. It may be an appropriate experimental model for investigating the effectiveness of bone regenerative agents in human alveolar bone loss.

Root development of rat tooth germs implanted in the tooth socket and in the subcutaneous tissue.

OBJECTIVE: This study was designed to investigate root development of a rat tooth germ implanted in a tooth socket or in a subcutaneous region. MATERIALS AND METHODS: Tooth germs of the upper left first molars in 2-week-old rats were extracted and implanted in the original tooth socket or in the subcutaneous region of the back. The upper right first molar was used as a control. The rats were fixed in weeks 1, 2, 4, 8 and 12. The root development was examined quantitatively with X-ray radiographic morphometry. The cellular activity of producing matrix proteins was assessed using in situ hybridization for type I collagen. RESULTS: Root development was observed in the implanted teeth in the tooth socket as also in the control teeth. In contrast, roots hardly developed in subcutaneously implanted teeth. Histology showed that periodontal ligaments were arranged around roots of implanted teeth in the tooth socket as around control teeth, but few periodontal ligaments were identified in the subcutaneous implantation. Dentin and cementum formed in both the implanted teeth as also in the control teeth and odontoblasts, cementoblasts and cementocytes expressed type I collagen. CONCLUSION: Tooth sockets may possess specific environments that allow root development of a tooth germ.

Development of gas pulsing system for electron cyclotron resonance ion source.

A gas-pulsing system for an electron cyclotron resonance ion source with all permanent magnets (Kei2 source) at NIRS has been developed and tested. The system consists of a small vessel (30 ml) to reserve CH(4) gas and two fast solenoid valves that are installed at both sides of the vessel. They are connected to each other and to the Kei2 source by using a stainless-steel pipe (4 mm inner diameter), where the length of the pipe from the valve to the source is 60 cm and the conductance is 1.2 l/s. From the results of the test, almost 300 e microA for a pulsed (12)C(4+) beam was obtained at a Faraday cup in an extraction-beam channel with a pressure range of 4000 Pa in the vessel. At this time, the valve has an open time of 10 ms and the delay time between the valve open time and the application of microwave power is 100 ms. In experiments, the conversion efficiency for input CH(4) molecules to the quantity of extracted (12)C(4+) ions in one beam pulse was found to be around 3% and the ratio of the total amount of the gas requirement was only 10% compared with the case of continuous gas provided in 3.3 s of repetition in HIMAC.

Atom probe specimen fabrication methods using a dual FIB/SEM.

A dual FIB/SEM provides solutions to many challenges in atom probe specimen preparation. When combined with an in situ lift-out capability, the versatility of this tool allows almost any region of interest, in almost any geometry, to be placed at the apex of a specimen tip. Several preparation techniques have been developed in response to specific application requirements; for example, in cases where materials are not suitable for electropolishing, or where site-specific analysis is required. Two general techniques, with wide-ranging potential applications, are described in detail here. The first is a 'cut-out' technique that provides a relatively quick means of micro-tip specimen preparation from bulk material samples. The second method is a 'lift-out' technique that can be used in an in situ or ex situ mode and does not require the preparation of pre-sharpened mounting points.

Kinetic studies of the old yellow enzyme. I. The reaction mechanism of the enzyme with reduced nicotinamide adenine dinucleotide.

The reaction mechanism of old yellow enzyme (NADPH:(acceptor) oxidoreductase, EC 1.6.99.1) was kinetically investigated using NADH as substrate. The enzyme was reduced by NADH via a reaction intermediate which has a specific absorption spectrum. This intermediate decomposed to yield a reduced enzyme and NAD+ through an inrreversible first-order reaction step. The reduced enzyme was reoxidized by oxygen through a second-order reaction process. Individual values of elementary rate constants were measured and a computer simulation of the reaction process was carried out. No involvement of free radical of flavin semiquinone in the reaction process could be shown.

Interaction of phospholipid liposomes with plasma membrane isolated from alveolar type II cells: effect of pulmonary surfactant protein A.

Pulmonary surfactant protein A (SP-A) augments the uptake of phospholipid liposomes containing dipalmitoylphosphatidylcholine (DPPC) by alveolar type II cells. The SP-A-mediated uptake process of lipids by type II cells have not been well understood. In the present study we investigated the SP-A-mediated interaction of phospholipids with plasma membrane isolated from alveolar type II cells. SP-A increased the amount of liposomes containing radiolabeled DPPC associated with type II cell plasma membrane by 4-fold compared to the control without SP-A when analyzed by sucrose density gradient centrifugation. This effect is dependent upon the SP-A concentration. The enhancement was inhibited by anti-SP-A antibody and EGTA. When type II cell plasma membrane and liposomes containing [14C]DPPC and [3H]triolein were coincubated with or without SP-A, analysis on sucrose density gradients revealed that the profiles of [14C]DPPC and [3H]triolein in each fraction were almost identical with or without SP-A, indicating that SP-A mediates the binding of liposomes to plasma membrane but not transfer of DPPC. SP-A increased the association of liposomes containing DPPC with the membrane by 2-fold more than that containing 1-palmitoyl-2-linoleoyl-phosphatidylcholine (PLPC). SP-A induced aggregation of phospholipid liposomes containing PLPC as well as those containing DPPC, but the final turbidity of DPPC liposomes aggregated by SP-A was only by 15% greater than that of PLPC liposomes. The amount of DPPC liposomes associated with the plasma membrane derived from type II cells was 2-fold greater than that from liver. We speculate that the SP-A-mediated interaction of lipids with type II cell plasma membrane may contribute, in part, to the lipid uptake process by type II cells.

Mobilization of endothelial progenitor cells in patients with acute myocardial infarction.

BACKGROUND: Endothelial progenitor cells (EPCs) circulate in adult peripheral blood (PB) and contribute to neovascularization. However, little is known regarding whether EPCs and their putative precursor, CD34-positive mononuclear cells (MNC(CD34+)), are mobilized into PB in acute ischemic events in humans. METHODS AND RESULTS: Flow cytometry revealed that circulating MNC(CD34+) counts significantly increased in patients with acute myocardial infarction (n=16), peaking on day 7 after onset, whereas they were unchanged in control subjects (n=8) who had no evidence of cardiac ischemia. During culture, PB-MNCs formed multiple cell clusters, and EPC-like attaching cells with endothelial cell lineage markers (CD31, vascular endothelial cadherin, and kinase insert domain receptor) sprouted from clusters. In patients with acute myocardial infarction, more cell clusters and EPCs developed from cultured PB-MNCs obtained on day 7 than those on day 1. Plasma levels of vascular endothelial growth factor significantly increased, peaking on day 7, and they positively correlated with circulating MNC(CD34+) counts (r=0.35, P=0.01). CONCLUSIONS: This is the first clinical demonstration showing that lineage-committed EPCs and MNC(CD34+), their putative precursors, are mobilized during an acute ischemic event in humans.

Development of a sensitive two-site immunoradiometric assay for parathyroid hormone-related peptide: evidence for elevated levels in plasma from patients with adult T-cell leukemia/lymphoma and B-cell lymphoma.

We have developed a sensitive immunoradiometric assay for PTH-related peptide (PTHrP) using a monoclonal antibody against PTHrP(1-34) and a polyclonal antibody against PTHrP(50-83), with recombinant human PTHrP(1-87) as the standard. The detection limit of the immunoradiometric assay was 0.5 pmol/L, and plasma PTHrP(1-87) concentrations in 110 healthy subjects were 0.8 +/- 0.01 pmol/L, with the upper limit of the normal range being 1.1 pmol/L. Increased circulating PTHrP(1-87) concentrations were demonstrated in all 46 cancer patients with hypercalcemia, but not in patients with primary hyperparathyroidism, chronic renal failure, or hypoparathyroidism. Normalization of serum calcium levels after resection of tumors was shown to correlate well with that of plasma PTHrP(1-87) concentrations in 2 cancer patients. High circulating PTHrP(1-87) levels were also demonstrated in 12 out of 13 hypercalcemic patients with adult T-cell leukemia/lymphoma and in 7 out of 8 hypercalcemic patients with non-Hodgkin's lymphoma especially of B-cell type. These results suggest that PTHrP is a major humoral factor responsible for the hypercalcemia frequently associated with adult T-cell leukemia/lymphoma and also with B-cell lymphoma.

A novel type of binding specificity to phospholipids for rat mannose-binding proteins isolated from serum and liver.

Mannose-binding protein (MBP) belongs to the collectin subgroup of C-type lectins with specificity for mannose and N-acetylglucosamine sugars. We investigated whether rat MBPs isolated from serum (S-MBP) and liver (L-MBP) interact with phospholipids using antibody against each MBP. Both S- and L-MBPs bound to phosphatidylinositol coated onto microtiter wells in a concentration- and a Ca2+-dependent manner. L-MBP also bound to phosphatidylglycerol and weakly to phosphatidylserine. MBPs interacted with liposomes composed of these lipids. S- and L-MBPs bound to phosphatidylinositol 4-monophosphate. L-MBP also bound to cardiolipin. These results provide evidence for a novel type of ligand binding specificity for MBPs, and raise the possibility that phospholipids are ligands for collectins.

Infantile neuroaxonal dystrophy: perinatal onset with symptoms of diencephalic syndrome.

In a neonatal case of infantile neuroaxonal dystrophy, there was emaciation, nystagmus, and endocrinologic disorder suggesting the diencephalic syndrome. At autopsy, spheroid bodies were widely disseminated, particularly in the hypothalamus, infundibulum, and neurohypophysis. The pathologic process may have started in utero.

Novel angiotensin II receptor antagonists. Design, synthesis, and in vitro evaluation of dibenzo[a,d]cycloheptene and dibenzo[b,f]oxepin derivatives. Searching for bioisosteres of biphenylyltetrazole using a three-dimensional search technique.

Three-dimensional substructure searching (3D search), using the program MACCS-3D, was utilized for designing novel angiotensin II receptor antagonists which contain a bioisostere of the biphenylyltetrazole moiety of DuP 753. A 3D query was prepared from an overlay model of substructures of several potent AII antagonists. The search system retrieved 139 compounds from the database MDDR-3D, which consisted of 29,400 medicinal patent compounds. A tricyclic compound was selected from the retrieved compounds and then evolved by considering steric fitness to the overlay model and synthetic feasibility. Finally, various novel AII antagonists having dibenzo[a,d]cycloheptene or dibenzo[b,f]oxepin were designed and synthesized. The receptor binding activity (Ki) for several members of this series was in the 10(-10) M range, demonstrating the ability of 3D search technique to explore new lead structures.

Structure-based generation of a new class of potent Cdk4 inhibitors: new de novo design strategy and library design.

As a first step in structure-based design of highly selective and potent Cdk4 inhibitors, we performed structure-based generation of a novel series of Cdk4 inhibitors. A Cdk4 homology model was constructed according to X-ray analysis of an activated form of Cdk2. Using this model, we applied a new de novo design strategy which combined the de novo design program LEGEND with our in-house structure selection supporting system SEEDS to generate new scaffold candidates. In this way, four classes of scaffold candidates including diarylurea were identified. By constructing diarylurea informer libraries based on the structural requirements of Cdk inhibitors in the ATP binding pocket of the Cdk4 model, we were able to identify a potent Cdk4 inhibitor N-(9-oxo-9H-fluoren-4-yl)-N'-pyridin-2-ylurea 15 (IC(50) = 0.10 microM), together with preliminary SAR. We performed a docking study between 15 and the Cdk4 model and selected a reasonable binding mode which is consistent with the SAR. Further modification based on the proposed binding mode provided a more potent compound, N-[(9bR)-5-oxo-2,3,5,9b-tetrahydro-1H-pyrrolo[2,1-a]isoindol-9-yl]-N'-pyridin-2-ylurea 26a (IC(50) = 0.042 microM), X-ray analysis of which was accomplished by the soaking method. The predicted binding mode of 15 in Cdk4 was validated by X-ray analysis of the Cdk2-26a complex.

A novel approach for the development of selective Cdk4 inhibitors: library design based on locations of Cdk4 specific amino acid residues.

Identification of a selective inhibitor for a particular protein kinase without inhibition of other kinases is critical for use as a biological tool or drug. However, this is very difficult because there are hundreds of homologous kinases and their kinase domains including the ATP binding pocket have a common folding pattern. To address this issue, we applied the following structure-based approach for designing selective Cdk4 inhibitors: (1) identification of specifically altered amino acid residues around the ATP binding pocket in Cdk4 by comparison of 390 representative kinases, (2) prediction of appropriate positions to introduce substituents in lead compounds based on the locations of the altered amino acid residues and the binding modes of lead compounds, and (3) library design to interact with the altered amino acid residues supported by de novo design programs. Accordingly, Asp99, Thr102, and Gln98 of Cdk4, which are located in the p16 binding region, were selected as first target residues for specific interactions with Cdk4. Subsequently, the 5-position of the pyrazole ring in the pyrazol-3-ylurea class of lead compound (2a) was predicted to be a suitable position to introduce substituents. We then designed a chemical library of pyrazol-3-ylurea substituted with alkylaminomethyl groups based on the output structures of de novo design programs. Thus we identified a highly selective and potent Cdk4 inhibitor, 15b, substituted with a 5-chloroindan-2-ylaminomethyl group. Compound 15b showed higher selectivity on Cdk4 over those on not only Cdk1/2 (780-fold/190-fold) but also many other kinases (>430-fold) that have been tested thus far. The structural basis for Cdk4 selective inhibition by 15b was analyzed by combining molecular modeling and the X-ray analysis of the Cdk4 mimic Cdk2-inhibitor complex. The results suggest that the hydrogen bond with the carboxyl group of Asp99 and hydrophobic van der Waals contact with the side chains of Thr102 and Gln98 are important. Compound 15b was found to cause cell cycle arrest of the Rb(+) cancer cell line in the G(1) phase, indicating that it is a good biological tool.

Ultrastructure of endothelial cell necrosis in classical erythema nodosum.

As evidence of vascular involvement in classical erythema nodosum unassociated with Behçet's disease, the occurrence of endothelial cell necrosis based on the development of dark cell degeneration was observed by electron microscopy in the vasculature of the dermis and subcutaneous fat. The incidence of endothelial cell necrosis in all segments of the microcirculatory system was roughly 20% in three of 12 patients. The remaining nine patients showed a very low rate of necrosis, including two patients in whom endothelial cell necrosis was totally absent. The presence of necrotic endothelial cells that are forced out and eliminated by neighboring intact endothelial cells into the vascular lumen is closely associated with thrombus formation in the cutaneous vasculature. The incidence at which endothelial cell necrosis occurs in classical erythema nodosum is not always high; however, it is concluded that endothelial cell necrosis may play a significant role in the pathogenesis of erythema nodosum.