Prototype and evaluation of automatic fingertip-blood-sampling system that uses fingertip blood-vessel images to determine puncture position.

We are developing an automatic fingertip-blood-sampling system to reduce the burden on trained medical personnel. For this system to withdraw a consistent volume of sampled blood for blood tests, we developed a mechanism for our system to select and puncture the vicinity of a large blood vessel from the blood-vessel image of an individual's fingertip. We call this mechanism the fingertip-vessel-puncture mechanism. From the results of an experiment in which the fingertips of 20 individuals (men and women in their 20 s to 60 s) were manually punctured at near and far locations from the blood vessel selected with our mechanism, the following conclusions were obtained. The fingertip-vessel-puncture mechanism tends to increase the volume of sampled blood, thus is effective in sampling more than 650 µL of blood for automatic blood analyzers. It was also found that it is more effective in increasing the volume of sampled blood in the men and those who were younger.

Bone Marrow Infiltration Is a Distinctive Risk Factor for Rituximab Infusion-Related Reactions in CD20-Positive B-Cell Non-Hodgkin Lymphoma.

BACKGROUND: Bone marrow infiltration of lymphoma cells is a candidate risk factor for infusion-related reactions (IRRs) in patients with CD20-positive B-cell non-Hodgkin lymphoma (B-NHL). However, despite with the lack of sufficient data, the effect of bone marrow infiltration of B-NHL cells on the incidence rate of grade 2 or higher IRRs with the administration of rituximab has been retrospectively studied in this paper. METHODS: Patients with CD20-positive B-NHL who received the rituximab induction therapy for the first time were enrolled in this study. To evaluate the bone marrow infiltration of B-NHL cells, May-Giemsa stain of bone marrow films and flow cytometry examination of bone marrow aspiration samples were performed. IRR grade was determined using the IRR criteria in the Common Terminology Criteria for Adverse Events version 4.0. RESULTS: A total of 127 patients were eligible for this study. Grade 2 or higher IRRs were observed in 43 (34%) patients. In univariate analysis, use of glucocorticoid before rituximab infusion was a strong risk-avoiding factor for grade 2 or higher IRRs. Advanced stage of disease (Ann Arbor: stages III and IV) or bone marrow infiltration of B-NHL cells revealed the risk factors, regardless of glucocorticoid premedication. Using multivariate analysis, bone marrow infiltration was found to be an independent risk factor for patients without prior glucocorticoid use. CONCLUSION: Bone marrow infiltration of B-NHL cells is a risk factor for grade 2 or higher IRRs at the first rituximab induction therapy without glucocorticoid premedication.

The association of high Vancomycin trough concentration with acute kidney injury during combination therapy of Piperacillin/Tazobactam and Vancomycin.

BACKGROUND: Co-administration of Piperacillin/Tazobactam (PIPC/TAZ) and Vancomycin (VCM) as an antibiotic therapy for severe infectious diseases increases the risk of nephrotoxicity. We retrospectively investigated the utility of monitoring VCM trough concentration in early stage of developing acute kidney injury (AKI) on this combination therapy. METHODS: We enrolled all infectious disease patients who were managed with concurrent PIPC/TAZ and VCM. The record of dosage and the administration interval of each antibiotic and its clinical parameters, as well as the VCM trough concentrations, blood culture for bacteria, and serum creatinine values, were collected. VCM trough concentration was measured during the initial 48-72 h of VCM administration. Nephrotoxicity was evaluated as the degree of AKI. RESULTS: A total of 47 patients fulfilling the criteria were registered, and AKI developed in 10 patients. There was no statistical difference between the AKI and non-AKI groups with regard to age, height, weight, basal creatinine level, body surface area, body mass index, PIPC/TAZ dose, VCM dose, gender, artificial management, and death within around 30 days. The VCM trough level was increased significantly in the AKI group (mean [standard deviation {SD}]: 25.9 [7.8] µg/mL) compared to that in the non-AKI group (mean [SD]: 15.7 [6.9] µg/mL) (p = 0.003). During the clinical course, renal function returned to normal levels in three out of four AKI stage 2 patients, whereas only partial recovery was achieved in all AKI stage 3 patients. CONCLUSIONS: A high VCM trough concentration may have an influence on the occurrence of AKI during combination therapy of PIPC/TAZ and VCM. Careful monitoring of VCM trough concentration will be required to prevent AKI progression.

Recurrent Fever due to Helicobacter cinaedi Infection during R-CHOP Chemotherapy in Diffuse Large B-Cell Lymphoma: Case Report and Literature Review.

Fever due to Helicobacter cinaedi bacteremia under chemotherapy has not been widely recognized among clinicians. We experienced a 72-year-old man with diffuse large B-cell lymphoma, who was complicated with H. cinaedi bacteremia-induced fever under R-CHOP chemotherapy. We summarized 6 cases including ours, suggesting that fever without neutropenia developing around day 6 from starting chemotherapy is a possible symptom caused by H. cinaedi bacteremia. We should discriminate fever due to H. cinaedi bacteremia if fever emerged before myelosuppression in the course of chemotherapy.

Transformation of Acute Myeloid Leukemia with Deletion of Chromosome 7q and Additional Abnormalities in Chromosome 8 in a Patient with Essential Thrombocythemia.

This is a case report of a 60-year-old male patient with essential thrombocythemia (ET) that progressed to acute myeloid leukemia (AML) in approximately 9 years. His platelet count decreased approximately 8 years after ET treatment with hydroxyurea (HU) and aspirin. The dose of HU was reduced because of suspected myelosuppression due to HU; however, myelosuppression did not improve. Bone marrow examination revealed myelofibrosis; therefore, ruxolitinib was administered. Approximately 1 year later, his leukocyte and blast counts in the peripheral blood increased; thus, ET was judged to have progressed to AML-myelodysplasia-related change. Induction chemotherapy and consolidation therapy were initiated; however, the patient unfortunately failed to achieve complete remission. We then continued to administer salvage chemotherapy; however, his general condition worsened, and he died from cerebral hemorrhage. The karyotype at the onset of ET was 46,XY, which changed to 47,XY,del(7q),+8 at the time of AML diagnosis. In addition, genetic testing revealed FLT-3 ITD mutation. His histopathological analysis showed subarachnoid and intraparenchymal hemorrhages and tumor cell infiltration into the cerebrum, brainstem, and cerebellum. In this case, deletion of the long arm of chromosome 7, additional abnormalities in chromosome 8, and FLT3-ITD mutation were confirmed as risk factors for having developed secondary AML for approximately 9 years and death from cerebral hemorrhage 1 year later.

Retro-aza-Michael reaction of an o-aminophenol adduct in protic solvents inspired by natural products.

α,ß-Unsaturated carbonyls are reactive group often found in bioactive small molecules. Their non-specific reaction with biomolecules can be the cause of the low efficacy and unexpected side-effects of the molecule. Accordingly, unprotected α,ß-unsaturated carbonyls are not often found in drugs. Here, we report that o-aminophenol is a new masking group of α,ß-unsaturated ketone, which is inspired by natural products saccharothriolides. o-Aminophenol adduct of α,ß-unsaturated ketone, but not those of α,ß-unsaturated amide or ester, undergoes a retro-Michael reaction to yield o-aminophenol and the Michael acceptor. This reaction was observed only in protic solvents, such as MeOH and aqueous MeOH. In contrast, o-anisidine was not eliminated from its Michael adduct. o-Aminophenol may be a promising masking tool of highly-reactive bioactive α,ß-unsaturated carbonyl compounds.

Relationship between PDGFR expression and the response to pazopanib in intimal sarcoma of the pulmonary artery: A case report.

Intimal sarcoma of the pulmonary artery (PAIS) is a rare disease with a poor prognosis. Pazopanib, which has been indicated in metastatic non-adipocytic soft-tissue sarcomas and is expected to be active in PAIS, is a multi-kinase inhibitor that targets the tyrosine kinase activity of vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR) and stem cell factor receptor. The present study reports findings related to two cases of PAIS with PDGF and VEGF expression following treatment with pazopanib. A case with a moderate to strong expression of PDGFR-α and -ß presented a long-term stable disease when treated with pazopanib (progression-free survival, 5.8 months). In a second case with a weak expression of PDGFR-α and -ß, the disease progressed rapidly on pazopanib (progression-free survival, 1.1 months). VEGFR-2 was not expressed in the tumors of both cases. The level of PDGFR expression in the tumor tissue may therefore be predictive of pazopanib efficacy.

Chemical Interactions of Cryptic Actinomycete Metabolite 5-Alkyl-1,2,3,4-tetrahydroquinolines through Aggregate Formation.

Organisms often produce secondary metabolites as a mixture of biosynthetically related congeners. However, why are metabolites with minor chemical variations produced simultaneously? 5-Alkyl-1,2,3,4-tetrahydroquinolines (5aTHQs) are small, lipophilic metabolites produced by Streptomyces nigrescens HEK616 when cultured with Tsukamurella pulmonis TP-B0596. A mixture of 5aTHQs forms aggregates that show enhanced membrane affinity and biological activity. The ability to form aggregates and membrane-binding activity is regulated by the length of the alkyl chains. Aggregates with long alkyl chains were too stable to fuse with lipid membranes. However, if inactive 5aTHQ congener was mixed with active congener, the mixture showed increased membrane affinity, enabling cellular entry and biological activity. Therefore, it is shown that sloppiness in a biosynthetic pathway, by which minor structural variations can be produced, is functionally rational, as the metabolites show synergistic action.

Adapalene Gel 0.1% Versus Placebo as Prophylaxis for Anti-Epidermal Growth Factor Receptor-Induced Acne-Like Rash: A Randomized Left-Right Comparative Evaluation (APPEARANCE).

LESSONS LEARNED: The results of the APPEARANCE trial indicate that adapalene does not prevent acne-like rash over placebo when added to topical moisturizer and oral minocycline but instead may have a detrimental effect. Therefore, adapalene is not recommended as prophylaxis against acne-like rash induced by anti-epidermal growth factor receptor therapies.Given that acne-like rash was completely controlled with placebo in approximately half of patients, predictive measures to identify patients needing intensive prophylaxis are required. BACKGROUND: Anti-epidermal growth factor receptor (EGFR) therapies are frequently associated with acne-like rash. To evaluate the prophylactic efficacy of adapalene, a topical retinoid used as first-line therapy for acne vulgaris, we conducted a randomized, placebo-controlled, evaluator-blinded, left-right comparative trial. METHODS: Patients with non-small cell lung, colorectal, or head and neck cancer scheduled to receive anti-EGFR therapies were randomly assigned to once-daily adapalene application on one side of the face, with placebo on the other side. All patients had topical moisturizer coapplied to both sides of the face, and received oral minocycline. The primary endpoint was the difference in total facial lesion count of acne-like rash at 4 weeks. Secondary endpoints included complete control rate (CCR) of acne-like rash (≤5 facial lesions) and global skin assessment (Investigator's Global Assessment [IGA] scale, grade 0-4) at 4 weeks. Two blinded dermatologists independently evaluated the endpoints from photographs. RESULTS: A total of 36 patients were enrolled, of whom 26 were evaluable. Adapalene treatment was associated with a greater lesion count than placebo at 4 weeks, although the difference was not statistically significant (mean, 12.6 vs. 9.8, p = .12). All four patients with a difference >10 in lesion count between face sides had a greater count on the adapalene-treated side. No significant differences were observed in CCR of acne-like rash (54% vs. 50%) or IGA scale (mean grade, 1.9 vs. 1.7) between the adapalene and placebo sides. CONCLUSION: Adapalene is not recommended as prophylaxis against acne-like rash induced by anti-EGFR therapies.

Discovery of Presaccharothriolide X, a Retro-Michael Reaction Product of Saccharothriolide B, from the Rare Actinomycete Saccharothrix sp. A1506.

The highly reactive precursor molecule, presaccharothriolide X, was successfully isolated from the rare actinomycete Saccharothrix sp. A1506. The comparable biological activity of presaccharothriolide X and its Michael addition product saccharothriolide B unveils a unique masking/activating property of 2-aminophenol. Unexpectedly, 2-aminophenol in saccharothriolide B was eliminated through a retro-Michael reaction, to yield presaccharothriolide X under physiological conditions. 2-Aminophenol might be developed into a useful protecting group for bioactive small molecules with an α,ß-unsaturated ketone.

Invasive Scopulariopsis alboflavescens infection in patient with acute myeloid leukemia.

Scopulariopsis alboflavescens is a soil saprophyte that is widely distributed in nature. Recently, there have been increasing number of reports of invasive infections with Scopulariopsis species in immunocompromised patients. In this report, we described an adult woman with acute myeloid leukemia and who developed S. alboflavescens pneumonia. Liposomal amphotericin B and voriconazole combination therapy was unsuccessful and the patient died because of pneumonia. Scopulariopsis is highly resistant to available antifungal agents and almost invariably fatal. This case report should alert clinicians to the importance of listing Scopulariopsis as a pathogenic fungus in immunocompromised patients.

Distribution of erlotinib in rash and normal skin in cancer patients receiving erlotinib visualized by matrix assisted laser desorption/ionization mass spectrometry imaging.

BACKGROUND: The development of skin rashes is the most common adverse event observed in cancer patients treated with epidermal growth factor receptor-tyrosine kinase inhibitors such as erlotinib. However, the pharmacological evidence has not been fully revealed. RESULTS: Erlotinib distribution in the rashes was more heterogeneous than that in the normal skin, and the rashes contained statistically higher concentrations of erlotinib than adjacent normal skin in the superficial skin layer (229 ± 192 vs. 120 ± 103 ions/mm2; P = 0.009 in paired t-test). LC-MS/MS confirmed that the concentration of erlotinib in the skin rashes was higher than that in normal skin in the superficial skin layer (1946 ± 1258 vs. 1174 ± 662 ng/cm3; P = 0.028 in paired t-test). The results of MALDI-MSI and LC-MS/MS were well correlated (coefficient of correlation 0.879, P < 0.0001). CONCLUSIONS: Focal distribution of erlotinib in the skin tissue was visualized using non-labeled MALDI-MSI. Erlotinib concentration in the superficial layer of the skin rashes was higher than that in the adjacent normal skin. METHODS: We examined patients with advanced pancreatic cancer who developed skin rashes after treatment with erlotinib and gemcitabine. We biopsied both the rash and adjacent normal skin tissues, and visualized and compared the distribution of erlotinib within the skin using matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). The tissue concentration of erlotinib was also measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with laser microdissection.

Airborne virus detection by a sensing system using a disposable integrated impaction device.

There are many respiratory infections such as influenza that cause epidemics. These respiratory infection epidemics can be effectively prevented by determining the presence or absence of infections in patients using frequent tests. We think that self-diagnosis may be possible using a system that can collect and detect biological aerosol particles in the patient's breath because breath sampling is easy work requiring no examiner. In this paper, we report a sensing system for biological aerosol particles (SSBAP) with a disposable device. Using the system and the device, someone with no medical knowledge or skills can safely, easily, and rapidly detect infectious biological aerosol particles. The disposable device, which is the core of the SSBAP, can be an impactor for biological aerosol particles, a flow-cell for reagents, and an optical window for the fluorescent detection of collected particles. Furthermore, to detect the fluorescence of very small collected particles, this disposable device is covered with a light-blocking film that lets only fluorescence of particles pass through a fluorescence detector of the SSBAP. The SSBAP using the device can automatically detect biological aerosol particles by the following process: collecting biological aerosol particles from a patient's breath in a sampling bag by the impaction method, labeling the collected biological aerosol particles with fluorescent dyes by the antigen-antibody reaction, removing free fluorescent dyes, and detecting the fluorescence of the biological aerosol particles. The collection efficiency of the device for microspheres aerosolized in the sampling bag was more than 97%, and the SSBAP with the device could detect more than 8.3 × 10(3) particles l(-1) of aerosolized influenza virus particles within 10 min.

The combination of HLA-B*15:01 and DRB1*15:01 is associated with gemcitabine plus erlotinib-induced interstitial lung disease in patients with advanced pancreatic cancer.

PURPOSE: In a phase III study of gemcitabine plus erlotinib for advanced pancreatic cancer conducted in Canada, the incidence of interstitial lung disease (ILD) was 3.5 %. However, the incidence of ILD was reported as high as 8.5 % in a Japanese phase II study. These results suggest the influence of ethnic factors in the association of the use of gemcitabine plus erlotinib with the incidence of ILD. Here, we conducted a prospective study to analyze the relationship between human leukocyte antigen (HLA) alleles and ILD in Japanese patients with advanced pancreatic cancer receiving gemcitabine plus erlotinib. METHODS: Patients were treated with gemcitabine (1000 mg/m(2); administered by intravenous infusion on days 1, 8, and 15 every 4 weeks) and erlotinib (given orally at 100 mg/day). We compared the frequencies of HLA alleles in patients who did and did not develop ILD. RESULTS: A total of 57 patients were treated, and 4 patients (7.0 %) developed ILD. The combination of HLA-B*15:01 and DRB1*15:01 was observed in 2 of 4 patients (50 %) with ILD and in only 1 of 53 patients without ILD (2 %) resulting in odds ratio of 52.0 (95 % CI 3.2-842.5; p = 0.011). CONCLUSION: These results suggest that the combination of HLA-B*15:01 and DRB1*15:01 is associated with ILD in Japanese patients with advanced pancreatic cancer receiving gemcitabine plus erlotinib.

Pd(II)-Catalyzed Alkylation of Tertiary Carbon via Directing-Group-Mediated C(sp(3))-H Activation: Synthesis of Chiral 1,1,2-Trialkyl Substituted Cyclopropanes.

A Pd(OAc)2-catalyzed alkylation reaction of the tertiary carbon of chiral cyclopropane substrates with alkyl iodides and bromides via C(sp(3))-H activation has been developed. This is an elusive example of a C-H activation-mediated alkylation of tertiary carbon to effectively construct a quaternary carbon center. The alkylation proceeded with various alkyl halides, including those of functional groups, to provide a variety of chiral cis- and trans-1,1,2,-trialkyl substituted cyclopropanes of medicinal chemical importance.

Mediastinal Germ Cell Tumor Exhibiting a Discrepancy between Tumor Markers and Imaging: A Case Study.

We report a mediastinal germ cell tumor (GCT) that exhibited a discrepancy between the time course of serum human chorionic gonadotropin (hCG) levels and clinical consequences. An otherwise healthy man, aged 34 years, was diagnosed with a nonseminomatous GCT, most likely embryonal carcinoma (EC), based on a mediastinal tumor biopsy. Standard chemotherapy resulted in an optimal decrease in serum hCG levels. However, multiple lesions in the liver continued to enlarge, which led to his death. Autopsy revealed few viable tumor cells in the liver, with the great majority of the tumor cells appearing to have undergone necrosis, suggesting that they responded to the chemotherapy. The residual tumor cells in the mediastinum and the liver were similar to syncytiotrophoblast cells, suggesting a cho-riocarcinoma (CC). On immunohistochemical analysis, the mediastinal tumor cells in the diagnostic biopsy specimen expressed both CD30 and hCG, whereas residual mediastinal and hepatic tumor cells in the autopsy specimen after chemotherapy also expressed hCG, but not CD30. These findings suggested that the patient suffered from a primary mixed GCT consisting of an EC and a CC. Both pre- and postchemotherapy tumors strongly expressed matrix metalloproteinase-2, supporting the aggressive and invasive features of the tumor phenotype. We speculate that the extremely invasive tumor destroyed normal liver structure, whereas chemotherapy and central necrosis reduced the number of viable cells themselves, causing a discordant decrease in serum hCG levels.

Phospholipase C-related inactive protein is involved in trafficking of gamma2 subunit-containing GABA(A) receptors to the cell surface.

The subunit composition of GABA(A) receptors is known to be associated with distinct physiological and pharmacological properties. Previous studies that used phospholipase C-related inactive protein type 1 knock-out (PRIP-1 KO) mice revealed that PRIP-1 is involved in the assembly and/or the trafficking of gamma2 subunit-containing GABA(A) receptors. There are two PRIP genes in mammals; thus the roles of PRIP-1 might be compensated partly by those of PRIP-2 in PRIP-1 KO mice. Here we used PRIP-1 and PRIP-2 double knock-out (PRIP-DKO) mice and examined the roles for PRIP in regulating the trafficking of GABA(A) receptors. Consistent with previous results, sensitivity to diazepam was reduced in electrophysiological and behavioral analyses of PRIP-DKO mice, suggesting an alteration of gamma2 subunit-containing GABA(A) receptors. The surface numbers of diazepam binding sites (alpha/gamma2 subunits) assessed by [3H]flumazenil binding were reduced in the PRIP-DKO mice as compared with those of wild-type mice, whereas the cell surface GABA binding sites (alpha/beta subunits, assessed by [3H]muscimol binding) were increased in PRIP-DKO mice. The association between GABA(A) receptors and GABA(A) receptor-associated protein (GABARAP) was reduced significantly in PRIP-DKO neurons. Disruption of the direct interaction between PRIP and GABA(A) receptor beta subunits via the use of a peptide corresponding to the PRIP-1 binding site reduced the cell surface expression of gamma2 subunit-containing GABA(A) receptors in cultured cell lines and neurons. These results suggest that PRIP is implicated in the trafficking of gamma2 subunit-containing GABA(A) receptors to the cell surface, probably by acting as a bridging molecule between GABARAP and the receptors.

GSK3beta positively regulates Hedgehog signaling through Sufu in mammalian cells.

Hedgehog signaling plays important roles in embryonic patterning of multicellular organisms. This pathway is ultimately transmitted by the zinc-finger transcriptional factor Gli, of which activity is suppressed by Sufu, a negative regulator of this signaling. To clarify this regulation to more detail, we screened for Sufu-binding proteins. We identified GSK3beta as a specific binding partner of Sufu by mass spectrometric analysis. GSK3beta bound to Sufu both in vitro and in vivo. Down-regulation of GSK3beta expression by RNAi in Hedgehog-responsive cells attenuated Hedgehog signaling, suggesting that GSK3beta functions as a positive regulator of Hedgehog signaling. In addition, an in vitro kinase assay showed that GSK3beta phosphorylates Sufu and phosphorylation-mimicking mutant of Sufu showed significantly decreased ability to bind Gli1 and could not suppress the Gli-mediated expression of a reporter gene efficiently. These results strongly suggest that GSK3beta phosphorylates Sufu to positively regulate Hedgehog signaling in mammalian cells.

Fused kinase is stabilized by Cdc37/Hsp90 and enhances Gli protein levels.

Serine/threonine kinase Fused (Fu) is an essential component of Hedgehog (Hh) signaling in Drosophila, but the biochemical functions of Fu remain unclear. Here, we have investigated proteins co-precipitated with mammalian Fu and identified a kinase-specific chaperone complex, Cdc37/Hsp90, as a novel-binding partner of Fu. Inhibition of Hsp90 function by geldanamycin (GA) induces rapid degradation of Fu through a ubiquitin-proteasome pathway. We next show that co-expression of Fu with transcription factors Gli1 and Gli2 significantly increases their protein levels and luciferase reporter activities, which are blocked by GA. These increases can be ascribed to Fu-mediated stabilization of Gli because co-expression of Fu prolongs half-life of Gli1 and reduces polyubiquitination of Gli1. Finally, we show that GA inhibits proliferation of PC3, a Hh signaling-activated prostate cancer cell line. This growth inhibition is partially rescued by expression of ectopic Gli1, suggesting that Fu may contribute to enhance Hh signaling activity in cancer cells.

Modulation of GABA(A) receptor phosphorylation and membrane trafficking by phospholipase C-related inactive protein/protein phosphatase 1 and 2A signaling complex underlying brain-derived neurotrophic factor-dependent regulation of GABAergic inhibition.

Brain-derived neurotrophic factor (BDNF) modulates several distinct aspects of synaptic transmission, including GABAergic transmission. Exposure to BDNF alters properties of GABA(A) receptors and induces changes in the expression level at the cell surface. Although phospholipase C-related inactive protein-1 (PRIP-1) plays an important role in GABA(A) receptor trafficking and function, its role in BDNF-dependent modulation of these receptors, together with the role of PRIP-2, was investigated using neurons cultured from PRIP double knock-out mice. The BDNF-dependent inhibition of whole cell GABA-evoked currents observed in wild type neurons was not detected in neurons cultured from knock-out mice. Instead, a gradual increase in GABA-evoked currents in these neurons correlated with a gradual increase in phosphorylation of GABA(A) receptor beta3 subunit in response to BDNF. To characterize the specific role(s) that PRIP plays as components of underlying molecular machinery, we examined the recruitment of protein phosphatase(s) to GABA(A) receptors. We demonstrate that PRIP associates with phosphatases as well as with beta subunits. PRIP was found to colocalize with GABA(A) receptor clusters in cultured neurons and with recombinant GABA(A) receptors when co-expressed in HEK293 cells. Importantly, a peptide mimicking a domain of PRIP involved in binding to beta subunits disrupted the co-localization of these proteins in HEK293 cells and potently inhibited the BDNF-mediated attenuation of GABA(A) receptor currents in wild type neurons. Together, the results suggest that PRIP plays an important role in BDNF-dependent regulation of GABA(A) receptors by mediating the specific association between beta subunits of these receptors with protein phosphatases.