A mechanical model reveals that non-axisymmetric buckling lowers the energy barrier associated with membrane neck constriction.

Membrane neck formation is essential for scission, which, as recent experiments on tubules have demonstrated, can be location dependent. The diversity of biological machinery that can constrict a neck such as dynamin, actin, ESCRTs and BAR proteins, and the range of forces and deflection over which they operate, suggest that the constriction process is functionally mechanical and robust to changes in biological environment. In this study, we used a mechanical model of the lipid bilayer to systematically investigate the influence of location, symmetry constraints, and helical forces on membrane neck constriction. Simulations from our model demonstrated that the energy barriers associated with constriction of a membrane neck are location-dependent. Importantly, if symmetry restrictions are relaxed, then the energy barrier for constriction is dramatically lowered and the membrane buckles at lower values of forcing parameters. Our simulations also show that constriction due to helical proteins further reduces the energy barrier for neck formation when compared to cylindrical proteins. These studies establish that despite different molecular mechanisms of neck formation in cells, the mechanics of constriction naturally leads to a loss of symmetry that can lower the energy barrier to constriction.

Whole-Genome Sequence of a Bordetella pertussis Brazilian Vaccine Strain.

Despite the reduction in incidence after vaccination, pertussis disease is still considered a public health problem worldwide, mainly due to recent and potential new outbreaks. We report here the complete genome of the Bordetella pertussis Butantan strain used in the Brazilian National Immunization Program as a whole-cell pertussis antigen to compose vaccines such as DTwP (diphtheria, tetanus, and whole-cell pertussis).

FGF-2 stimulates periodontal regeneration: results of a multi-center randomized clinical trial.

The efficacy of the local application of recombinant human fibroblast growth factor-2 (FGF-2) in periodontal regeneration has been investigated. In this study, a randomized, double-blind, placebo-controlled clinical trial was conducted in 253 adult patients with periodontitis. Modified Widman periodontal surgery was performed, during which 200 µL of the investigational formulation containing 0% (vehicle alone), 0.2%, 0.3%, or 0.4% FGF-2 was administered to 2- or 3-walled vertical bone defects. Each dose of FGF-2 showed significant superiority over vehicle alone (p < 0.01) for the percentage of bone fill at 36 wks after administration, and the percentage peaked in the 0.3% FGF-2 group. No significant differences among groups were observed in clinical attachment regained, scoring approximately 2 mm. No clinical safety problems, including an abnormal increase in alveolar bone or ankylosis, were identified. These results strongly suggest that topical application of FGF-2 can be efficacious in the regeneration of human periodontal tissue that has been destroyed by periodontitis.

Successful third kidney transplantation with intensive immunosuppression in a highly sensitized recipient.

HLA sensitization associated with previous kidney transplantation is a major drawback to retransplantation. Recently we successfully performed a third graft using intensive immunosuppression for a highly sensitized recipient. The patient was a 31-year-old man who had previously undergone a living donor graft from his father at our institute in 1999. His kidney graft function had deteriorated due to chronic allograft nephropathy, returning to hemodialysis therapy in 2005. He received a second graft from a deceased donor in another country on August 14, 2006. It rejected on postoperative day 3 possibly due to acute accelerated rejection. He was offered a third kidney from his brother. Panel-reactive antibody (PRA) tested before the third procedure revealed positive class I (88%) and class II (96%) PRAs. Mycophenolate mofetil (MMF) was started 3 weeks before the third transplantation, and preoperative plasmapheresis performed thrice. He underwent the living donor graft on March 9, 2007. Immunosuppression consisted of tacrolimus, MMF, methylprednisolone, and basiliximab. Immediately afterward there was a sudden decrease in allograft blood flow and urine output, implying hyperacute rejection. Following treatment with plasmapheresis and a single dose of rituximab (200 mg), the kidney allograft function recovered, although the PRA at 3 weeks was still positive. Six months posttransplantation, he is well with a creatinine of 0.9 mg/dL. Our protocol may reduce the risk for graft loss in a highly sensitized transplant recipient.

"A system biology" approach to bioinformatics and functional genomics in complex human diseases: arthritis.

Human and other annotated genome sequences have facilitated generation of vast amounts of correlative data, from human/animal genetics, normal and disease-affected tissues from complex diseases such as arthritis using gene/protein chips and SNP analysis. These data sets include genes/proteins whose functions are partially known at the cellular level or may be completely unknown (e.g. ESTs). Thus, genomic research has transformed molecular biology from "data poor" to "data rich" science, allowing further division into subpopulations of subcellular fractions, which are often given an "-omic" suffix. These disciplines have to converge at a systemic level to examine the structure and dynamics of cellular and organismal function. The challenge of characterizing ESTs linked to complex diseases is like interpreting sharp images on a blurred background and therefore requires a multidimensional screen for functional genomics ("functionomics") in tissues, mice and zebra fish model, which intertwines various approaches and readouts to study development and homeostasis of a system. In summary, the post-genomic era of functionomics will facilitate to narrow the bridge between correlative data and causative data by quaint hypothesis-driven research using a system approach integrating "intercoms" of interacting and interdependent disciplines forming a unified whole as described in this review for Arthritis.

Non-competitive GABA antagonists: probing the mechanisms of their selectivity for insect versus mammalian receptors.

A great variety of non-competitive antagonists of ionotropic gamma-aminobutyric acid (GABA) receptors have been reported. While they are structurally diverse, there are common features in their structures. Thus, it was hypothesized that they bind to an identical site in different or overlapping orientations, and this hypothesis was validated by three-dimensional structure-activity relationship (3D-QSAR) analysis using receptor-binding data. Meanwhile, although most antagonists are highly toxic to both vertebrates and invertebrates, several classes of antagonists, such as nor-diterpene lactone picrodendrins, phenyl heterocyclic compounds and disubstituted bicyclophosphorothionates, were found to exhibit selectivity for housefly versus rat GABA receptors. To probe their selectivity mechanisms, the 3D-QSAR method was applied to the three classes of antagonists. This revealed several important differences that might be related to the selectivity of antagonists between the structures of the non-competitive antagonist-binding sites of housefly and rat GABA receptors.

Neurofibromatosis type 1 with basilar artery fusiform aneurysm manifesting Wallenberg's syndrome.

A case of neurofibromatosis type 1 (NF1) manifesting Wallenberg's syndrome and fusiform aneurysm of the basilar artery is reported. The patient suddenly developed dysarthria, walking difficulty and sensory disturbance. Neurological examination suggested Wallenberg's syndrome and MR imaging confirmed an ischemic lesion at the left lateral medulla oblongata. Cerebral angiography revealed a fusiform aneurysm at the middle portion of the basilar artery. However, there was no occlusive change in either the posterior inferior cerebellar artery or the vertebral artery. The clinical and radiological features are discussed together with a review of NF1 cases with intracranial aneurysms in the literature.

An electromyographic investigation of the effect of stimulus-response mapping on choice reaction time.

The activity of the agonist muscles was recorded during the performance of a two-choice visual reaction time (RT) task in which the compatibility of the stimulus-response mapping was manipulated. Correct trials were distinguished according to whether or not the activation of the agonist of the required response was preceded by an activation of the agonist of the nonrequired response. Double activation trials were more numerous for the incompatible than for the compatible mapping. Furthermore, these trials yielded longer RTs than the single muscular activation trials. These results suggest that initial activations of nonrequired responses are more frequently aborted and corrected when the mapping is incompatible than when it is compatible. This finding supports the dimensional overlap model of stimulus-response compatibility (S. Kornblum, T. Hasbroucq, & A. Osman, 1990).

Structure-activity relationship study of host-specific phytotoxins (AM-toxin analogs) using a new assay method with leaves from apple meristem culture.

AM-toxins are host-specific phytotoxins of the Alternaria alternata apple pathotype, which induce necrosis on apple leaves. In this study, we developed a new assay to measure the necrotic activity of AM-toxin analogs using cultured leaves from meristem cells. This method was not only more sensitive to AM-toxin I, but also more reliable than the previous one that used tree leaves due to the homogeneous nature of cultured leaves and to the method of application of toxins. Using this assay method we investigated a structure-activity relationship of AM-toxin analogs synthesized in this study. Most residues and the macrocyclic ring structure were strictly recognized by AM-toxin putative receptor, whereas the L-Ala binding subsite of the receptor allowed for side chain structures with various stereoelectronic properties. These findings are important for designing ligands for further experimental probing of the nature of the receptor.

[Percutaneous tumor ablation therapy for the advanced stage of HCC].

We have performed percutaneous tumor ablation (PTA) including percutaneous ethanol injection therapy (PEIT) for 90% of the patients with hepatocellular carcinoma. Until December 1998, the 793 patients received PTA, 5 years survival rate reached 39.8%. Excluding the patients with Child C whose hepatic function were extremely low, 5 years survival rate reached to the level of 41.2%. Since 5 years survival rate in stage IV-A reached 24.4%, the patients of stage IV-A may be considered to have an indication for PTA. We have confirmed the effectiveness of the local treatment including radiotherapy for advanced hepatocellular carcinoma with portal vein invasion. We are attempting to perform PTA for the extra-hepatic lesions that had no indication of other treatment. However the indication of PTA is limited by the presence of diffuse nodules, exacerbation of the hepatic function, or tumor invasion to portal vein, bile duct, inferior vena cava.

Three-dimensional quantitative structure-activity relationship analyses of RGD mimetics as fibrinogen receptor antagonists.

In order to better understand the structural requirements of fibrinogen receptor antagonists, variations in the platelet aggregation inhibitory activity of a series of RGD mimetics were examined using techniques for the analysis of three-dimensional quantitative structure activity relationship, such as CoMFA.

Changes in spinal excitability during choice reaction time: the H reflex as a probe of information transmission.

The aim of the present study was to investigate the modulations in amplitude of H reflexes elicited in a hand muscle, the flexor pollicis brevis, during the performance of a choice reaction time (RT) task in which this muscle was directly involved. Ten subjects were to choose between a left- or a right-thumb key-press according to the lateral location of a flash of light. The stimulus-response mapping was either compatible or incompatible. Hoffman reflexes were elicited at different times during the RT by stimulation of the median nerve. Twenty-five milliseconds before the voluntary response, the amplitude of the H reflex suddenly increased when the muscle was involved in the response and decreased symmetrically when the muscle was not involved in the response. Mapping compatibility exerted no detectable influence on the changes in spinal excitability. The latter result supports the assumptions that are at the core of Sternberg's additive factor method.

Structure-activity relationships of RGD mimetics as fibrinogen-receptor antagonists.

The activities of a series of RGD mimetics, which contained a variety of cationic structures, for the inhibition of platelet aggregation and fibrinogen-receptor binding were measured. The stability of the coulombic ion-pairing complex of the model compounds with the acetate anion as a model for the receptor was calculated in terms of the ionic interaction energy. The results suggest that stability is one of the significant factors which govern the inhibitory potency of fibrinogen-receptor binding. The distance between cationic and anionic groups might also affect the potency. A compound which contained an amidinophenyl structure as the cationic moiety showed exceptionally high inhibitory activity, suggesting that some other factors, in addition to coulombic interaction and the distance, affect the potency.

Vinexin forms a signaling complex with Sos and modulates epidermal growth factor-induced c-Jun N-terminal kinase/stress-activated protein kinase activities.

Vinexin, a novel protein that plays a key role in cell spreading and cytoskeletal organization, contains three SH3 domains and binds to vinculin through its first and second SH3 domains. We show here that the third SH3 domain binds to Sos, a guanine nucleotide exchange factor for Ras and Rac, both in vitro and in vivo. Point mutations in the third SH3 domain abolished the vinexin-Sos interaction. Stimulation of NIH/3T3 cells with serum, epidermal growth factor (EGF), or platelet-derived growth factor (PDGF) decreased the electrophoretic mobility of Sos and concomitantly inhibited formation of the vinexin-Sos complex. Phosphatase treatment of lysates restored the binding of Sos to vinexin, suggesting that signaling from serum, EGF, or PDGF regulates the vinexin-Sos complex through the Sos phosphorylation. To evaluate the function of vinexin downstream of growth factors, we examined the effects of wild-type and mutant vinexin expression on extracellular signal-regulated kinase (Erk) and c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) activation in response to EGF. Exogenous expression of vinexin beta in NIH/3T3 cells enhanced JNK/SAPK activation but did not affect Erk activation. Moreover mutations in the third SH3 domain abolished EGF activation of JNK/SAPK in a dominant-negative fashion, whereas they slightly stimulated Erk. Together these results suggest that vinexin can selectively modulate EGF-induced signal transduction pathways leading to JNK/SAPK kinase activation.

Sensorimotor polyneuropathy associated with chronic lymphocytic leukemia, IgM antigangliosides antibody and human T-cell leukemia virus I infection.

A 65-year-old man presented with a sensorimotor polyneuropathy associated with B-cell chronic lymphocytic leukemia (CLL) and immunoglobulin M (IgM) antibody to various gangliosides. Electrophysiological studies denoted significant abnormalities of motor and sensory nerve conduction. Although the pathology of sural nerve biopsy looked minimally affected, immunohistochemical studies showed specific binding of IgM to the human peripheral nerve. Our patient also had high titer of antibody to human T-cell leukemia virus I (HTLV-I) in both serum and cerebrospinal fluid (CSF), which might activate B-cell-mediated immunity and facilitate the production of IgM antibody. The other unique feature is the reactivity of antibody to gangliosides. The patient had IgM antibody reactivities to gangliosides with disialosyl residue such as GT1b, GQ1b and GD3, but not to GD1b. IgM antibody to gangliosides with disialosyl residue has been reported in ataxic symptoms, but our patient failed to demonstrate ataxia. Without reactivity to GD1b, sensory ataxic neuropathy might not develop even in the presence of antibody reactive to other gangliosides with disialosyl residue.