A P2X purinoceptor expressed by a subset of sensory neurons

ATP is known to depolarize sensory neurons, and may play a role in nociceptor activation when released from damaged tissue. Here we report the molecular cloning and characterization of a new member of the P2X receptor family, P2X3, expressed by these cells. The channel transcript was present in a subset of rat dorsal-root-ganglion sensory neurons, some of which express nociceptor-associated markers; it was absent in other tissues that were tested, including sympathetic, enteric and central nervous system neurons. Moreover, when expressed in Xenopus oocytes, the channel showed an ATP-dependent cation flux. P2X3 is the only ligand-gated channel known to be expressed exclusively by a subset of sensory neurons. The remarkable selectivity of expression of the channel coupled with its sensory neuron-like pharmacology suggests that this channel may transduce ATP-evoked nociceptor activation.

Age, thymopoiesis, and CD4+ T-lymphocyte regeneration after intensive chemotherapy

BACKGROUND

Inadequate reconstitution of CD4+ T lymphocytes is an important clinical problem complicating chemotherapy, human immunodeficiency virus infection, and bone marrow transplantation, but relatively little is known about how CD4+ T lymphocytes regenerate. There are two main possibilities: bone marrow-derived progenitors could reconstitute the lymphocyte population using a thymus-dependent pathway, or thymus-independent pathways could predominate. Previous studies have suggested that the CD45RA glycoprotein on CD4+ T lymphocytes is a marker for progeny generated by a thymus-dependent pathway.

METHODS

We studied 15 patients 1 to 24 years of age who had undergone intensive chemotherapy for cancer. The absolute numbers of CD4+ T lymphocytes in peripheral blood and the expression of CD45 isoforms (CD45RA and CD45RO) on these lymphocytes were studied serially during lymphocyte regeneration after the completion of therapy. Radiographic imaging of the thymus was performed concomitantly.

RESULTS

There was an inverse relation between the patients' ages and the CD4+ T-lymphocyte counts six months after therapy was completed (r = -0.92). The CD4+ recovery correlated quantitatively with the appearance of CD45RA+CD4+ T lymphocytes in the blood (r = 0.64). There was a higher proportion of CD45RA+CD4+ T lymphocytes in patients with thymic enlargement after chemotherapy than in patients without such enlargement (two-sided P = 0.015).

CONCLUSIONS

Thymus-dependent regeneration of CD4+ T lymphocytes occurs primarily in children, whereas even young adults have deficiencies in this pathway. Our results suggest that rapid T-cell regeneration requires residual thymic function in patients receiving high-dose chemotherapy.

Catalytic growth and characterization of gallium nitride nanowires

The preparation of high-purity and -quality gallium nitride nanowires is accomplished by a catalytic growth using gallium and ammonium. A series of catalysts and different reaction parameters were applied to systematically optimize and control the vapor-liquid-solid (VLS) growth of the nanowires. The resulting nanowires show predominantly wurtzite phase; they were up to several micrometers in length, typically with diameters of 10-50 nm. A minimum nanowire diameter of 6 nm has been achieved. Temperature dependence of photoluminescence spectra of the nanowires revealed that the emission mainly comes from wurtzite GaN with little contribution from the cubic phase. Moreover, the thermal quenching of photoluminescence was much reduced in the GaN nanowires. The Raman spectra showed five first-order phonon modes. The frequencies of these peaks were close to those of the bulk GaN, but the modes were significantly broadened, which is indicative of the phonon confinement effects associated with the nanoscale dimensions of the system. Additional Raman modes, not observed in the bulk GaN, were found in the nanowires. The field emission study showing notable emission current with low turn-on field suggests potential of the GaN nanowires in field emission applications. This work opens a wide route toward detailed studies of the fundamental properties and potential applications of semiconductor nanowires.

The association between Internet addiction and psychiatric disorder: a review of the literature

Internet addiction is a newly emergent disorder. It has been found to be associated with a variety of psychiatric disorders. Information about such coexisting psychiatric disorders is essential to understand the mechanism of Internet addiction. In this review, we have recruited articles mentioning coexisting psychiatric disorders of Internet addiction from the PubMed database as at November 3, 2009. We describe the updated results for such disorders of Internet addiction, which include substance use disorder, attention-deficit hyperactivity disorder, depression, hostility, and social anxiety disorder. We also provide discussion for possible mechanisms accounting for the coexistence of psychiatric disorders and Internet addiction. The review might suggest that combined psychiatric disorders mentioned above should be evaluated and treated to prevent their deteriorating effect on the prognosis of Internet addiction. On the other hand, Internet addiction should be paid more attention to when treating people with these coexisting psychiatric disorders of Internet addiction. Additionally, we also suggest future necessary research directions that could provide further important information for the understanding of this issue.

A sensory neuron-specific, proton-gated ion channel

Proton-gated channels expressed by sensory neurons are of particular interest because low pH causes pain. Two proton-gated channels, acid-sensing ionic channel (ASIC) and dorsal root ASIC (DRASIC), that are members of the amiloride-sensitive ENaC/Degenerin family are known to be expressed by sensory neurons. Here, we describe the cloning and characterization of an ASIC splice variant, ASIC-beta, which contains a unique N-terminal 172 aa, as well as unique 5' and 3' untranslated sequences. ASIC-beta, unlike ASIC and DRASIC, is found only in a subset of small and large diameter sensory neurons and is absent from sympathetic neurons or the central nervous system. The patterns of expression of ASIC and ASIC-beta transcripts in rat dorsal root ganglion neurons are distinct. When expressed in COS-7 cells, ASIC-beta forms a functional channel with electrophysiological properties distinct from ASIC and DRASIC. The pH dependency and sensitivity to amiloride of ASIC-beta is similar to that described for ASIC, but unlike ASIC, the channel is not permeable to calcium, nor are ASIC-beta-mediated currents inhibited by extracellular calcium. The unique distribution of ASIC-beta suggests that it may play a specialized role in sensory neuron function.

Fisp12/mouse connective tissue growth factor mediates endothelial cell adhesion and migration through integrin alphavbeta3, promotes endothelial cell survival, and induces angiogenesis in vivo

Fisp12 was first identified as a secreted protein encoded by a growth factor-inducible immediate-early gene in mouse fibroblasts, whereas its human ortholog, CTGF (connective tissue growth factor), was identified as a mitogenic activity in conditioned media of human umbilical vein endothelial cells. Fisp12/CTGF is a member of a family of secreted proteins that includes CYR61, Nov, Elm-1, Cop-1/WISP-2, and WISP-3. Fisp12/CTGF has been shown to promote cell adhesion and mitogenesis in both fibroblasts and endothelial cells and to stimulate cell migration in fibroblasts. These findings, together with the localization of Fisp12/CTGF in angiogenic tissues, as well as in atherosclerotic plaques, suggest a possible role for Fisp12/CTGF in the regulation of vessel growth during development, wound healing, and vascular disease. In this study, we show that purified Fisp12 (mCTGF) protein promotes the adhesion of microvascular endothelial cells through the integrin receptor alphavbeta3. Furthermore, Fisp12 stimulates the migration of microvascular endothelial cells in culture, also through an integrin-alphavbeta3-dependent mechanism. In addition, the presence of Fisp12 promotes endothelial cell survival when cells are plated on laminin and deprived of growth factors, a condition that otherwise induces apoptosis. In vivo, Fisp12 induces neovascularization in rat corneal micropocket implants. These results demonstrate that Fisp12 is a novel angiogenic inducer and suggest a direct role for Fisp12 in the adhesion, migration, and survival of endothelial cells during blood vessel growth. Taken together with the recent finding that the related protein CYR61 also induces angiogenesis, we suggest that Fisp12/mCTGF and CYR61 comprise prototypes of a new family of angiogenic regulators that function, at least in part, through integrin-alphavbeta3-dependent pathways.

Somatostatin receptor scintigraphy: its sensitivity compared with that of other imaging methods in detecting primary and metastatic gastrinomas. A prospective study

OBJECTIVE

To compare the sensitivity of somatostatin receptor scintigraphy done using [111In-DTPA-DPhe1]octreotide with that of other imaging methods in the localization of gastrinomas in patients with the Zollinger-Ellison syndrome.

DESIGN

Prospective study.

SETTING

Referral-based clinical research center.

PATIENTS

80 consecutive patients with the Zollinger-Ellison syndrome.

INTERVENTIONS

Conventional tumor localization studies (ultrasonography, computed tomography [CT], magnetic resonance imaging [MRI], selective angiography, and bone scanning) and somatostatin receptor scintigraphy done using [111In-DTPA-DPhe1]octreotide with single-photon emission CT imaging at 4 and 24 hours. Patients with possible liver metastases had biopsies done for confirmation, and 15 patients had exploratory laparotomies done to assess primary tumor localization.

RESULTS

Extrahepatic gastrinomas or liver metastases were identified by ultrasonography in 19% of patients, by CT in 38% of patients, by MRI in 45% of patients, by angiography in 40% of patients, and by somatostatin receptor scintigraphy in 70% of patients. Somatostatin receptor scintigraphy was as sensitive as the other tests combined (59%), and when the results of all other tests were added to the somatostatin receptor scintigraphy results, tumors were localized in 75% of patients. Among patients with a possible primary tumor, the results of ultrasonography were positive in 9%, the results of CT were positive in 31%, the results of MRI were positive in 30%, the results of angiography were positive in 28%, and the results of somatostatin receptor scintigraphy were positive in 58%. Somatostatin receptor scintigraphy was as sensitive as all of the other imaging studies combined; when the results of scintigraphy were added to the results of the other studies, possible primary tumors were identified in 68% of patients. In 24 patients who had histologically proven metastatic liver disease, sensitivities for the detection of any metastatic liver lesions were 46% for ultrasonography, 42% for CT, 71% for MRI, 62% for angiography, and 92% for somatostatin receptor scintigraphy. Somatostatin receptor scintigraphy was significantly better than all of the conventional imaging methods in the identification of gastrinomas later found at surgery (P = 0.004), but it still missed 20% of gastrinomas.

CONCLUSIONS

Somatostatin receptor scintigraphy is the single most sensitive method for imaging either primary or metastatic liver lesions in patients with the Zollinger-Ellison syndrome. Because of its sensitivity, simplicity, and cost-effectiveness, it should be the first imaging method used in these patients. For patients with negative results on somatostatin receptor scintigraphy, guidelines about the use of other imaging studies are proposed.

Interaction between the functional polymorphisms of the alcohol-metabolism genes in protection against alcoholism

The genes that encode the major enzymes of alcohol metabolism, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), exhibit functional polymorphism. The variant alleles ADH2*2 and ADH3*1, which encode high-activity ADH isoforms, and the ALDH2*2 allele, which encodes the low-activity form of ALDH2, protect against alcoholism in East Asians. To investigate possible interactions among these protective genes, we genotyped 340 alcoholic and 545 control Han Chinese living in Taiwan at the ADH2, ADH3, and ALDH2 loci. After the influence of ALDH2*2 was controlled for, multiple logistic regression analysis indicated that allelic variation at ADH3 exerts no significant effect on the risk of alcoholism. This can be accounted for by linkage disequlibrium between ADH3*1 and ADH2*2 ALDH2*2 homozygosity, regardless of the ADH2 genotypes, was fully protective against alcoholism; no individual showing such homozygosity was found among the alcoholics. Logistic regression analyses of the remaining six combinatorial genotypes of the polymorphic ADH2 and ALDH2 loci indicated that individuals carrying one or two copies of ADH2*2 and a single copy of ALDH2*2 had the lowest risk (ORs 0.04-0.05) for alcoholism, as compared with the ADH2*1/*1 and ALDH2*1/*1 genotype. The disease risk associated with the ADH2*2/*2-ALDH2*1/*1 genotype appeared to be about half of that associated with the ADH2*1/*2-ALDH2*1/*1 genotype. The results suggest that protection afforded by the ADH2*2 allele may be independent of that afforded by ALDH2*2.

Psychosocial and psychiatric risk factors for suicide. Case-control psychological autopsy study

BACKGROUND

Few studies of suicide have simultaneously examined the individual and combined effects of psychosocial and psychiatric risk factors.

AIMS

To do so in a representative sample of suicides.

METHOD

A case-control psychological autopsy was conducted among 113 consecutive suicides and 226 living controls matched for age, gender, ethnicity and area of residence in Taiwan.

RESULTS

Five major risk factors (loss event, suicidal behaviour in first-degree relatives, ICD-10 major depressive episode, emotionally unstable personality disorder and substance dependence) were found to have independent effects on suicide from multivariate conditional logistic regression analysis.

CONCLUSIONS

Effective intervention and management for loss event and major depressive episode among emotionally unstable subjects with a family tendency of suicidal behaviour, frequently also comorbid with alcohol or other substance dependence, may prove to be most effective for suicide prevention in different populations.

Comprehensive evaluation of 35 patients with lymphangioleiomyomatosis

OBJECTIVES

To evaluate comprehensively the characteristics of lymphangioleiomyomatosis (LAM), with emphasis on the application of imaging and immunohistochemical methods.

DESIGN

Prospective study.

PATIENTS

Thirty-five female subjects with LAM.

SETTING

Clinical Center, National Institutes of Health.

INTERVENTIONS

BAL, pulmonary function test, ventilation/perfusion lung scans, CT of the chest and abdomen, ultrasonography of abdomen, and immunohistochemical study of lung biopsy specimens.

RESULTS

Most patients had exertional dyspnea (83%) and pneumothorax (69%). BAL did not show diagnostic changes. The most common abnormalities on pulmonary function tests were decreased diffusing capacity of carbon monoxide (83%), hypoxemia (57%), and airway obstruction (51%). Bronchodilator response was found in 26% of patients. CT, which is almost pathognomonic, showed numerous thin-walled cysts throughout both lungs in all patients. Thirty-four patients (97%) had abnormal ventilation and/or perfusion lung scans. An unusual "speckling" pattern was observed on ventilation scans of 74% of patients. Common extrapulmonary features were retroperitoneal adenopathy (77%) and renal angiomyolipomas (60%). The percentage of abnormal smooth muscle cells (LAM cells), reactive with HMB45, varied from 17 to 67% in 10 lung biopsy specimens.

CONCLUSIONS

Improved diagnostic methods have defined the abnormalities in patients with pulmonary LAM and increased the potential for early recognition and treatment of this disorder. Patients with LAM should be evaluated for bronchodilator responsiveness and may benefit from a trial of bronchodilators.

Size Dependence of Structural Metastability in Semiconductor Nanocrystals

The kinetics of a first-order, solid-solid phase transition were investigated in the prototypical nanocrystal system CdSe as a function of crystallite size. In contrast to extended solids, nanocrystals convert from one structure to another by single nucleation events, and the transformations obey simple unimolecular kinetics. Barrier heights were observed to increase with increasing nanocrystal size, although they also depend on the nature of the nanocrystal surface. These results are analogous to magnetic phase transitions in nanocrystals and suggest general rules that may be of use in the discovery of new metastable phases.

The angiogenic factors Cyr61 and connective tissue growth factor induce adhesive signaling in primary human skin fibroblasts

The angiogenic inducers cysteine-rich angiogenic protein 61 (Cyr61) and connective tissue growth factor (CTGF) are structurally related, extracellular matrix-associated heparin-binding proteins. Both can stimulate chemotaxis and promote proliferation in endothelial cells and fibroblasts in culture and induce neovascularization in vivo. Encoded by inducible immediate early genes, Cyr61 and CTGF are synthesized upon growth factor stimulation in cultured fibroblasts and during cutaneous wound healing in dermal fibroblasts. Recently, we have shown that adhesion of primary human fibroblasts to immobilized Cyr61 is mediated through integrin alpha(6)beta(1) and cell surface heparan sulfate proteoglycans (HSPGs) (Chen, N., Chen, C.-C., and Lau, L.F. (2000) J. Biol. Chem. 275, 24953-24961), providing the first demonstration of an absolute requirement for HSPGs in integrin-mediated cell attachment. We show in this study that CTGF also mediates fibroblast adhesion through the same mechanism and demonstrate that fibroblasts adhesion to immobilized Cyr61 or CTGF induces distinct adhesive signaling responses consistent with their biological activities. Compared with fibroblast adhesion to fibronectin, laminin, or type I collagen, cell adhesion to Cyr61 or CTGF induces 1) more extensive and prolonged formation of filopodia and lamellipodia, concomitant with formation of integrin alpha(6)beta(1)-containing focal complexes localized at leading edges of pseudopods; 2) activation of intracellular signaling molecules including focal adhesion kinase, paxillin, and Rac with similar rapid kinetics; 3) sustained activation of p42/p44 MAPKs lasting for at least 9 h; and 4) prolonged gene expression changes including up-regulation of MMP-1 (collagenase-1) and MMP-3 (stromelysin-1) mRNAs and proteins sustained for at least 24 h. Together, these results establish Cyr61 and CTGF as bona fide adhesive substrates with specific signaling capabilities, provide a molecular basis for their activities in fibroblasts through integrin alpha(6)beta(1) and HSPG-mediated signaling during attachment and indicate that these proteins may function in matrix remodeling through the activation of metalloproteinases during angiogenesis and wound healing.

The angiogenic factor Cyr61 activates a genetic program for wound healing in human skin fibroblasts

Cyr61 is a heparin-binding, extracellular matrix-associated protein of the CCN family, which also includes connective tissue growth factor, Nov, WISP-1, WISP-2, and WISP-3. Cyr61 is capable of multiple functions, including induction of angiogenesis in vivo. Purified Cyr61 mediates cell adhesion and induces adhesive signaling, stimulates cell migration, enhances cell proliferation, and promotes cell survival in both fibroblasts and endothelial cells. In this study, we have used cDNA array hybridization to identify genes regulated by Cyr61 in primary human skin fibroblasts. The Cyr61-regulated genes fall into several groups known to participate in processes important for cutaneous wound healing, including: 1) angiogenesis and lymphogenesis (VEGF-A and VEGF-C); 2) inflammation (interleukin-1beta); 3) extracellular matrix remodeling (MMP1, MMP3, TIMP1, uPA, and PAI-1); and 4) cell-matrix interactions (Col1alpha1, Col1alpha2, and integrins alpha(3) and alpha(5)). Cyr61-mediated gene expression requires heparin binding activity of Cyr61, cellular de novo transcription, and protein synthesis and is largely dependent on the activation of p42/p44 MAPKs. Cyr61 regulates gene expression not only in serum-free medium but also in fibroblasts cultured on various matrix proteins or in the presence of 10% serum. These effects of Cyr61 can be sustained for at least 5 days, consistent with the time course of wound healing in vivo. Interestingly, Cyr61 can interact with transforming growth factor-beta1 to regulate expression of specific genes in an antagonistic, additive, or synergistic manner. Furthermore, we show that the Cyr61 gene is highly induced in dermal fibroblasts of granulation tissue during cutaneous wound repair. Together, these results show that Cyr61 is inducibly expressed in granulation tissues after wounding and that Cyr61 activates a genetic program for wound repair in skin fibroblasts. We propose a model in which Cyr61 integrates its activities on endothelial cells, fibroblasts, and macrophages to regulate the processes of angiogenesis, inflammation, and matrix remodeling in the context of cutaneous wound healing.

Levels of interleukin-1 beta and interleukin-8 in gingival crevicular fluids in adult periodontitis

Recent in vitro findings indicate that cytokines represent an important pathway of connective tissue destruction in human periodontitis. The biological effects of interleukin-1 beta (IL-1 beta) and interleukin-8 (IL-8) are relevant in this regard, and the objective of this study was to compare the levels of these molecules in gingival crevicular fluids (GCF) from patients with adult periodontitis (experimental group) and from individuals with clinically healthy gingiva (control group). GCF was collected for 30 seconds using a periopaper strip and the volume of the sample determined. Following elution of the fluid, assays for IL-1 beta and IL-8 were carried out by ELISA. The concentrations (ng/ml) of cytokines were calculated in the original volume of GCF on each strip. The total amounts (pg/site) of cytokines were expressed as the concentrations multiplied by volumes of GCF: The total amounts of IL-1 beta and IL-8 of the experimental group were significantly higher than the control group. The total amounts of both cytokines were markedly reduced following phase 1 periodontal treatment. The clinical parameters were positively related to the total amounts of IL-1 beta and IL-8. IL-1 beta concentrations and total amounts were also positively related to IL-8 suggesting that the GCF IL-8 levels are influenced by local IL-1 beta activities. These data indicate that the total amounts of IL-1 beta and IL-8 exhibited dynamic changes upon severity of periodontal disease. The levels of IL-1 beta and IL-8 in GCF are valuable in detecting the inflammation of periodontal tissue.

Cyr61 and Fisp12 are both ECM-associated signaling molecules: activities, metabolism, and localization during development

cyr61 and fisp12 are homologous immediate-early genes that are transcriptionally activated upon growth factor stimulation in fibroblasts. Their gene products belong to an emerging family of secreted proteins with a high degree of sequence homology, including conservation of all 38 cysteine residues in their secreted portions. We have recently shown that Cyr61 is an extracellular matrix (ECM) signaling molecule that promotes cell proliferation, migration, and adhesion. We describe herein the first purification of the Fisp12 protein and we compare the activities of purified Cyr61 and Fisp12, their metabolism, targeting, and their localization during development. Although Fisp12 is the mouse homolog of the human connective tissue growth factor (CTGF), it has no detectable mitogenic activity by itself. Rather, Fisp12 enhances fibroblast growth factor-induced DNA synthesis. The activities of Fisp12 and Cyr61 are nearly indistinguishable in three cell types tested: fibroblasts, endothelial, and epithelial cells. Both proteins are found in the ECM, although Cyr61 associates with the ECM more strongly and binds heparin with higher affinity. Fisp12, but not Cyr61, is also found in the culture medium, suggesting that Fisp12 might be able to act at a distance from its site of secretion, whereas Cyr61 might act more locally. Both secreted proteins are internalized and degraded through the lysosomal pathway, suggesting interaction with cell surface receptors. Both Cyr61 and Fisp12 are found in the placenta and the circulatory system as detected by immunohistochemistry, whereas Cyr61, but not Fisp12, is found in the skeletal and nervous systems. Fisp12, but not Cyr61, is found in secretory organs. Taken together, we propose that Cyr61 and Fisp12 are both signaling cell adhesion molecules that have similar or overlapping activities, and their differential sites of localization and targeting may dictate specificity in their biological roles.

Immediate diagnosis of acute myocardial infarction by two-dimensional echocardiography

To define the role of portable two-dimensional echocardiography (2-D echo) in the immediate diagnosis of acute chest pain syndrome, 80 consecutive patients were studied. Adequate 2-D echo studies were obtained in 65 (81%). Thirty-three patients had clinical evidence of transmural or nontransmural acute myocardial infarction (AMI), 18 of whom had nondiagnostic initial ECGs. Thirty-two did not have a clinical AMI. Thirty-one of the 33 (94%) patients with clinical AMI had regional wall motion abnormalities on the initial 2-D echo; the other two had uncomplicated nontransmural AMIs, diagnosed only by ECG in one and by ECG and moderate elevation of CK-MB isoenzyme in the other. Twenty-seven of the 32 patients without clinical AMI had normal regional wall motion on the initial 2-D echo and none had a complication (severe arrhythmia, recurrent pain, heart failure or death) during the hospital course. Conversely, 10 of the 36 patients with initial 2-D echo regional wall motion abnormalities had a complication (p less than 0.05). Thus, in patients with acute chest pain syndrome, an initial 2-D echo that shows no regional wall motion abnormality suggests that such patients will not develop an AMI or clinical complication during the hospital course. An initial 2-D echo with regional wall motion abnormality identifies a high-risk group of patients who are likely to have AMI and important cardiac complications and may, therefore, benefit from admission to an intensive care unit.

A concept analysis of malnutrition in the elderly

PURPOSE

Malnutrition is a frequent and serious problem in the elderly. Today there is no doubt that malnutrition contributes significantly to morbidity and mortality in the elderly. Unfortunately, the concept of malnutrition in the elderly is poorly defined. The purpose of this paper is to clarify the meaning of malnutrition in the elderly and to develop the theoretical underpinnings, thereby facilitating communication regarding the phenomenon and enhancing research efforts.

SCOPE, SOURCES USED

Critical review of literature is the approach used to systematically build and develop the theoretical propositions. Conventional search engines such as Medline, PsyINFO, and CINAHL were used. The bibliography of obtained articles was also reviewed and additional articles identified. Key wards used for searching included malnutrition, geriatric nutrition, nutritional status, nutrition assessment, elderly, ageing, and weight loss.

CONCLUSIONS

The definition of malnutrition in the elderly is defined as following: faulty or inadequate nutritional status; undernourishment characterized by insufficient dietary intake, poor appetite, muscle wasting and weight loss. In the elderly, malnutrition is an ominous sign. Without intervention, it presents as a downward trajectory leading to poor health and decreased quality of life. Malnutrition in the elderly is a multidimensional concept encompassing physical and psychological elements. It is precipitated by loss, dependency, loneliness and chronic illness and potentially impacts morbidity, mortality and quality of life.

The paired Ig-like receptor PIR-B is an inhibitory receptor that recruits the protein-tyrosine phosphatase SHP-1

An emerging family of cell surface inhibitory receptors is characterized by the presence of intracytoplasmic immunoreceptor tyrosine-based inhibition motifs (ITIM). These ITIM-bearing inhibitory receptors, which are typically paired with activating isoforms, associate with Src homology domain 2-containing phosphatases following ITIM tyrosine phosphorylation. Two categories of phosphatases are recruited by the ITIM-bearing receptors: the protein-tyrosine phosphatases, SHP-1 and SHP-2, and the polyphosphate inositol 5-phosphatase, SHIP. The dynamic equilibrium of B cell activation is partially controlled by two well known ITIM-bearing receptors, CD22 and FcgammaRIIB, a low affinity receptor for IgG. We describe here that a murine ITIM-bearing molecule, PIR-B, can also negatively regulate B cell activation. Tyrosine-phosphorylated ITIMs allow PIR-B to associate with SHP-1 but not with SHIP. Engagement of PIR-B thereby initiates a SHP-1-dependent inhibitory pathway that may play an important role in regulating B lymphocyte activation.

Magnolol and honokiol isolated from Magnolia officinalis protect rat heart mitochondria against lipid peroxidation

In isolated rat heart mitochondria lipid peroxidation was induced with ADP and ferrous sulfate (FeSO4). Oxygen consumption and malondialdehyde (MDA) production were measured to quantitate lipid peroxidation. The antioxidant effects of magnolol and honokiol purified from Magnolia officinalis were 1000 times higher than that of alpha-tocopherol. The IC50 values of magnolol and honokiol for inhibition of oxygen consumption were 8.0 x 10(-8) M and 1.0 x 10(-7) M, respectively, while that of alpha-tocopherol was 1.0 x 10(-4) M. Magnolol at 0.5 microM inhibited 71.4 +/- 9.4% of oxygen consumption and 59.3 +/- 4.6% MDA production. At the same concentration, honokiol inhibited 78.1 +/- 4.7% of oxygen consumption and 86.9 +/- 4.0% of MDA production. Of conjugated diene formation 48.4 +/- 4.6% and 53.1 +/- 3.4% were inhibited by 0.5 microM magnolol and honokiol, respectively. Also both magnolol and honokiol exhibited free radical scavenging activities as shown by the diphenyl-p-picrylhydrazyl assay, but they were less potent than alpha-tocopherol.

Activation-dependent adhesion of human platelets to Cyr61 and Fisp12/mouse connective tissue growth factor is mediated through integrin alpha(IIb)beta(3)

Cyr61 and connective tissue growth factor (CTGF), members of a newly identified family of extracellular matrix-associated signaling molecules, are found to mediate cell adhesion, promote cell migration and enhance growth factor-induced cell proliferation in vitro, and induce angiogenesis in vivo. We previously showed that vascular endothelial cell adhesion and migration to Cyr61 and Fisp12 (mouse CTGF) are mediated through integrin alpha(v)beta(3). Both Cyr61 and Fisp12/mCTGF are present in normal blood vessel walls, and it has been demonstrated that CTGF is overexpressed in advanced atherosclerotic lesions. In the present study, we examined whether Cyr61 and Fisp12/mCTGF could serve as substrates for platelet adhesion. Agonist (ADP, thrombin, or U46619)-stimulated but not resting platelets adhered to both Cyr61 and Fisp12/mCTGF, and this process was completely inhibited by prostaglandin I(2), which prevents platelet activation. The specificity of Cyr61- and Fisp12/mCTGF-mediated platelet adhesion was demonstrated by specific inhibition of this process with polyclonal anti-Cyr61 and anti-Fisp12/mCTGF antibodies, respectively. The adhesion of ADP-activated platelets to both proteins was divalent cation-dependent and was blocked by RGDS, HHLGGAKQAGDV, or echistatin, but not by RGES. Furthermore, this process was specifically inhibited by the monoclonal antibody AP-2 (anti-alpha(IIb)beta(3)), but not by LM609 (anti-alpha(v)beta(3)), indicating that the interaction is mediated through integrin alpha(IIb)beta(3). In a solid phase binding assay, activated alpha(IIb)beta(3), purified by RGD affinity chromatography, bound to immobilized Cyr61 and Fisp12/mCTGF in a dose-dependent and RGD-inhibitable manner. In contrast, unactivated alpha(IIb)beta(3) failed to bind to either protein. Collectively, these findings identify Cyr61 and Fisp12/mCTGF as two novel activation-dependent adhesive ligands for the integrin alpha(IIb)beta(3) on human platelets, and implicate a functional role for these proteins in hemostasis and thrombosis.

Mutations in microphthalmia, the mouse homolog of the human deafness gene MITF, affect neuroepithelial and neural crest-derived melanocytes differently

The mouse microphthalmia (Mitf) gene encodes a basic-helix-loop-helix-zipper transcription factor whose mutations are associated with abnormalities in neuroepithelial and neural crest-derived melanocytes. In wild type embryos, Mitf expression in neuropithelium and neural crest precedes that of the melanoblast marker Dct, is then co-expressed with Dct, and gradually fades away except in cells in hair follicles. In embryos with severe Mitf mutations, neural crest-derived Mitf-expressing cells are rare, lack Dct expression, and soon become undetectable. In contrast, the neuroepithelial-derived Mitf-expressing cells of the retinal pigment layer are retained, express Dct, but not the melanogenic enzyme genes tyrosinase and Tyrp1, and remain unpigmented. The results show that melanocyte development critically depends on functional Mitf and that Mitf mutations affect the neural crest and the neuroepithelium in different ways.

A new member of the acid-sensing ion channel family

Acid-sensing ion channels (ASICs) are members of the epithelial sodium channel (ENaC)-degenerin family of two-pass transmembrane segment protein subunits which form multimeric cation channels. Members of the ENaC-degenerin family are gated by stimuli as diverse as protons, peptides and mechanical distension. Here we describe a new member of the family, SPASIC or ASIC 4 (spinal cord ASIC) which is expressed throughout the central nervous system in an overlapping population of neurons that also express the ASIC subunit MDEG2. ASIC-4 which shows 44% identify with ASIC is developmentally regulated and expressed in a subset of sensory neurons as well as in the CNS. However, despite the strong homology with ASIC, the ASIC-4 transcript does not encode a proton gated cation channel.

Synthesis of Todorokite

Todorokite of chemical composition (Mg(0.77)Na(0.03))(Mg(0.18)Mn(2+)(0.60)Mn(4+)(5.22)22) O(12).3.07 H(2)O was synthesized by a two-step procedure. First, sodium birnessite was synthesized and magnesium was exchanged for sodium to form magnesium birnessite, which was autoclaved under a saturated steam pressure at 155 degrees C for 8 hours to form well-crystallized todorokite. Synthesized todorokite particles consisted of fibers extending from a central plate. The plate itself was made of twinned fibers forming a trilling pattern. The infrared spectra and x-ray diffraction patterns were similar to those of natural todorokite samples. Calcium birnessite and nickel birnessite, when autoclaved under conditions similar to those for magnesium birnessite, yielded a todorokite structure. However, the formation of todorokite from calcium and nickel birnessite was less extensive.

6-[18F]fluorodopamine positron emission tomographic (PET) scanning for diagnostic localization of pheochromocytoma

The diagnosis and treatment of pheochromocytoma depend critically on effective means to localize the tumor. Computed tomography and magnetic resonance imaging have good sensitivity but poor specificity for detecting pheochromocytoma, and nuclear imaging approaches such as (131)I-metaiodobenzylguanidine scintigraphy have limited sensitivity. Here we report initial results using 6-[(18)F]fluorodopamine positron emission tomography (PET) scanning in the diagnostic localization of pheochromocytoma. Twenty-eight patients with known or clinically suspected pheochromocytoma underwent PET scanning after intravenous injection of 6-[(18)F]fluorodopamine. Of the 28 patients, 9 had surgical confirmation of the tumor, 8 had previously diagnosed metastatic pheochromocytoma, and 11 had plasma levels of metanephrines that were within normal limits. All 9 patients with surgically proven pheochromocytoma had abnormal 6-[(18)F]fluorodopamine PET scans that identified the tumors. All 8 patients with metastatic pheochromocytoma had extra-adrenal sites of 6-[(18)F]fluorodopamine-derived activity. Of the 11 patients with normal plasma levels of metanephrines, 9 had negative 6-[(18)F]fluorodopamine PET scans, 1 had extra-adrenal foci of 6-[(18)F]fluorodopamine-derived activity, and 1 had symmetric uptake of 6-[(18)F]fluorodopamine in the region of the adrenal glands. In patients with known disease, 6-[(18)F]fluorodopamine PET scanning can detect and localize pheochromocytomas with high sensitivity. In patients in whom the diagnosis of pheochromocytoma is considered but excluded because of negative plasma metanephrine results, 6-[(18)F]fluorodopamine PET scans are consistently negative. These findings justify a clinical trial of 6-[(18)F]fluorodopamine PET scanning as a diagnostic tool.

Randomized trial of the cardioprotective agent ICRF-187 in pediatric sarcoma patients treated with doxorubicin

PURPOSE

We conducted an open-label, randomized trial to determine whether ICRF-187 would reduce doxorubicin-induced cardiotoxicity in pediatric sarcoma patients.

METHODS

Thirty-eight patients were randomized to receive doxorubicin-containing chemotherapy (given as an intravenous bolus) with or without ICRF-187. Resting left ventricular ejection fraction (LVEF) was monitored serially with multigated radionuclide angiography (MUGA) scan. The two groups were compared for incidence and degree of cardiotoxicity, response rates to four cycles of chemotherapy, event-free and overall survival, and incidence and severity of noncardiac toxicities.

RESULTS

Eighteen ICRF-187-treated and 15 control patients were assessable for cardiac toxicity. ICRF-187-treated patients were less likely to develop subclinical cardiotoxicity (22% v 67%, P < .01), had a smaller decline in LVEF per 100 mg/m2 of doxorubicin (1.0 v 2.7 percentage points, P = .02), and received a higher median cumulative dose of doxorubicin (410 v 310 mg/m2, P < .05) than did control patients. Objective response rates were identical in the two groups, with no significant differences seen in event-free or overall survival. ICRF-187-treated patients had a significantly higher incidence of transient grade 1 serum transaminase elevations and a trend toward increased hematologic toxicity.

CONCLUSION

ICRF-187 reduces the risk of developing short-term subclinical cardiotoxicity in pediatric sarcoma patients who receive up to 410 mg/m2 of doxorubicin. Response rates to chemotherapy, event-free and overall survival, and noncardiac toxicities appear to be unaffected by the use of ICRF-187. Additional clinical trials with larger numbers of patients are needed to determine if the short-term cardioprotection afforded by ICRF-187 will reduce the incidence of late cardiac complications in long-term survivors of childhood cancer.