Working memory components modulation of attentional disengagement from evaluative distractor

It is important for people to disengage attention from a distraction, which can help them complete the task at hand as quickly as possible. Recent studies have shown that people's attention stays longer on reward-distractors than on loss-distractors, and a delay in attentional disengagement is noted when reward-distractors are present. However, few studies have examined whether attentional disengagement from an evaluative distractor relies upon working memory (WM) components. In the present study, we used an attentional disengagement paradigm in which reward- or loss-distractors were presented at a central location and the target was presented at a peripheral location, in combination with different WM tasks. The results from Experiment 1 showed that participants were slower to disengage their attention from a central reward-distractor than a loss-distractor regardless of cognitive load when the phonological loop component of WM was involved. The results from Experiment 2 revealed that people had difficulty in shifting their attention away from a reward-distractor in comparison to a loss-distractor when spatial WM was low, whereas no such difference was observed when spatial WM was high. We conclude that WM components differently modulate attentional disengagement from evaluative distractors. That is, the processing of evaluative (reward and loss) distractors may rely on the same cognitive resources as the spatial WM component, but not the phonological loop component.

Model-Informed Dosing Regimen of Ticagrelor in Chinese Patients With Acute Coronary Syndrome

The exposure to ticagrelor (BRILINTA) is higher in the East Asian population compared with the White population, thus, East Asians have an increased risk of bleeding. We developed a population pharmacokinetic (PopPK) model of ticagrelor based on a randomized 3 × 3 crossover study in healthy subjects. The area under the concentration-time curve (AUC) of Chinese patients with acute coronary syndrome was simulated based on this model. Following this, eight machine learning (ML) methods were used to construct bleeding risk models. Variables included in the final bleeding risk model were age, hypertension, body weight, AUC, drinking status, calcium channel blockers, antidiabetic medications, β-blockers, peripheral vascular disease, diabetes, transient ischemic attack, sex, and proton pump inhibitor. In terms of F1 scores and area under the curve of receiver operating characteristic curve (ROC-AUC), the Random Forest model performed best among all models, with an F1 score of 0.73 and ROC-AUC of 0.81. Moreover, the PopPK model and ML algorithm were used to bridge the real-world data to build a bleeding risk prediction model based on drug exposure and clinical information. Using this model, a ticagrelor regimen that is associated with a lower risk of bleeding in individuals can be obtained. This model should be further validated prospectively in clinical settings.

Different patterns of foreground and background processing contribute to texture segregation in humans: an electrophysiological study

Background

Figure-ground segregation is a necessary process for accurate visual recognition. Previous neurophysiological and human brain imaging studies have suggested that foreground-background segregation relies on both enhanced foreground representation and suppressed background representation. However, in humans, it is not known when and how foreground and background processing play a role in texture segregation.

Methods

To answer this question, it is crucial to extract and dissociate the neural signals elicited by the foreground and background of a figure texture with high temporal resolution. Here, we combined an electroencephalogram (EEG) recording and a temporal response function (TRF) approach to specifically track the neural responses to the foreground and background of a figure texture from the overall EEG recordings in the luminance-tracking TRF. A uniform texture was included as a neutral condition. The texture segregation visual evoked potential (tsVEP) was calculated by subtracting the uniform TRF from the foreground and background TRFs, respectively, to index the specific segregation activity.

Results

We found that the foreground and background of a figure texture were processed differently during texture segregation. In the posterior region of the brain, we found a negative component for the foreground tsVEP in the early stage of foreground-background segregation, and two negative components for the background tsVEP in the early and late stages. In the anterior region, we found a positive component for the foreground tsVEP in the late stage, and two positive components for the background tsVEP in the early and late stages of texture processing.

Discussion

In this study we investigated the temporal profile of foreground and background processing during texture segregation in human participants at a high time resolution. The results demonstrated that the foreground and background jointly contribute to figure-ground segregation in both the early and late phases of texture processing. Our findings provide novel evidence for the neural correlates of foreground-background modulation during figure-ground segregation in humans.

Physiologically Based Pharmacokinetic Model for Older Adults and Its Application in Geriatric Drug Research

Drug-related adverse events are higher in older patients than in non-older patients, increasing the risk of medication and reducing compliance. Aging is accompanied by a decline in physiological functions and metabolic weakening. Most tissues and organs undergo anatomical and physiological changes that may affect the pharmacokinetic (PK) and pharmacodynamic (PD) characteristics of drugs. Clinical trials are the gold standard for selecting appropriate dosing regimens. However, older patients are generally underrepresented in clinical trials, resulting in a lack of evidence for establishing an optimal dosing regimen for older adults. The physiologically based pharmacokinetic (PBPK) model is an effective approach to quantitatively describe the absorption, distribution, metabolism, and excretion of drugs in older adults by integrating physiological parameters, drug physicochemical properties, and preclinical or clinical PK data. The PBPK model can simulate the PK/PD characteristics of clinical drugs in different scenarios, ultimately compensating for inadequate clinical trial data in older adults, and is recommended by the Food and Drug Administration for clinical pharmacology studies in older adults. This review describes the effects of physiological changes on the PK/PD process in older adults and summarises the research progress of PBPK models. Future developments of PBPK models are also discussed, together with the application of PBPK models in older adults, aiming to assist the development of clinical study strategies in older adults.

Potential genotoxicity from integration sites in CLAD dogs treated successfully with gammaretroviral vector-mediated gene therapy

Integration site analysis was performed on six dogs with canine leukocyte adhesion deficiency (CLAD) that survived greater than 1 year after infusion of autologous CD34+ bone marrow cells transduced with a gammaretroviral vector expressing canine CD18. A total of 387 retroviral insertion sites (RIS) were identified in the peripheral blood leukocytes from the six dogs at 1 year postinfusion. A total of 129 RIS were identified in CD3+ T-lymphocytes and 102 RIS in neutrophils from two dogs at 3 years postinfusion. RIS occurred preferentially within 30 kb of transcription start sites, including 40 near oncogenes and 52 near genes active in hematopoietic stem cells. Integrations clustered around common insertion sites more frequently than random. Despite potential genotoxicity from RIS, to date there has been no progression to oligoclonal hematopoiesis and no evidence that vector integration sites influenced cell survival or proliferation. Continued follow-up in disease-specific animal models such as CLAD will be required to provide an accurate estimate of the genotoxicity using gammaretroviral vectors for hematopoietic stem cell gene therapy.

Implication of human epidermal growth factor receptor-2 (HER-2) over expression in treatment of breast cancer in developing countries—report on 250 cases from Bangladesh

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Background: Carcinoma breast is the second most common malignancy in Bangladeshi women. Though HER-2 over expression has profound effect on prognosis of breast cancer, no published data is available about this among Bangladeshi patients. Our aim in this study was to see HER-2 status in Bangladeshi patients, and their relation with other prognostic parameters. Implication of this molecular marker in management of breast cancer in poor country like ours remains controversial, keeping in mind the exorbitantly high cost of Trastuzumab. Methods: This prospective study was conducted in the department of Oncology at Bangladesh Medical College Hospital, National Institute of Cancer Research and Hospital and Ahsania Mission Cancer Hospital Bangladesh, from January 2003 to December 2006. Total 250 women with breast carcinoma were enrolled; biopsy specimens were tested by immunohistochemistry to detect HER-2 status. For recommending treatment with Trastuzumab, patients with 3+ immunohistochemistry results were considered HER-2 positive. Fluorescent In Situ Hybridization (FISH) testing facility was not available. These findings were correlated with age, ER/PR and nodal status. The practical application of marker in terms of use of Trastuzumab was analyzed. Results: Age of patients ranged from 19.75 years to 72 years, mean age was 49.75 years. HER-2 was over expressed in 38.4 % (96) cases and their mean age was 42.92 years compared to 47.61 years in HER-2 negative cases. HER-2 positive cases tended to have higher rates of lymph node metastases (44 out of 96) compared to HER-2 negative (46 out of 154) cases (45.8 % vs 29.87 %). ER/PR was positive in 64 % cases. HER-2 over expression was inversely related to ER / PR expression. Of the HER-2 positive cases, 11.45 % (11 out of 96) afforded treatment with Trastuzumab. Conclusions: HER-2 is over expressed in almost 38 % of breast carcinoma patients in Bangladesh. This expression is associated with relatively young age, lymph node metastasis and lack of ER / PR expression. Only 11.45 % of patients with HER-2 over expression afforded Trastuzumab though 38 % of cases over expressed HER-2.

No significant financial relationships to disclose.

Capecitabine therapy in advanced gall bladder cancer: A phase II study

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Background: Thymidine phosphorylase (TP) activity is found at higher levels in gall bladder cancer (GBC) tissues than in adjacent healthy tissues. GBC is relatively sensitive to 5-FU. TP activated capecitabine (CAP) mimics the continuous infusion of 5-FU. In view of drug potentiality this present study was initiated. Our aim was to evaluate the therapeutic efficacy and safety of CAP in previously untreated GBC patients (Pts). Methods: It was an open-labelled, single-centred, non-randomised and prospective study. Outcome measures were response rate and type of response for efficacy measurement and safety was measured by adverse events & laboratory blood values (LBV). All LBV were within reference range at baseline. The patients had no prior chemo/ radio therapy or a family history of malignancy; adenocarcinoma (stage III–IV); age 40–70 yrs; male/female: 16/ 30; KPS ≥ 70%. 46 pts were treated with 306 cycles (min 3–max 12) of CAP at a dose of 2500 mg/day in two divided doses from day 1–14 followed by 1-week rest. Results: Median age was 50 yrs. Hand foot syndrome occurred in 17.39% pts, diarrhoea (grade 3 & 4) 21.75% and both 15.21%, all toxicities were manageable. Mean LBV before and after CAP therapy were hemoglobin: 11.38–0.35 g/dl (95% CI, 10.66–2.10); total count of WBC: 9,260–580/mm3 (95% CI, 8,680–9,840); platelet count: 251,000–2,000/mm3 (95% CI, 227,000–275,000) and serum bilirubin: 1.17–0.33 mg/dl (95% CI, 0.5–1.84). The LBV between baseline and after CAP therapy were not statistically significant. Partial response was found in 12 pts (26.08%), stable disease in 26 pts (56.21%), and progressive disease in 8 pts (17.39%). Mean KPS value after therapy was 76% (95% CI, 69–84). Conclusion: This clinical experience indicates that CAP is a convenient choice in phase II chemo naïve GBC pts not adversely affecting haematological values.

No significant financial relationships to disclose.

Conversion of the severe to the moderate disease phenotype with donor leukocyte microchimerism in canine leukocyte adhesion deficiency

Leukocyte adhesion deficiency-1 (LAD-1), a genetic immunodeficiency disease characterized by life-threatening bacterial infections, results from the defective adherence and migration of leukocytes due to mutations in the leukocyte integrin CD18 molecule. Canine LAD (CLAD) represents the canine homologue of the severe phenotype of LAD-1 in children. In previous studies we demonstrated that non-myeloablative stem cell transplantation from matched littermates resulted in mixed donor-host chimerism and reversal of the disease phenotype in CLAD. In this study, we describe two CLAD dogs with less than 2% donor leukocyte chimerism following non-myeloablative transplant. Both dogs are alive more than 24 months after transplant with an attenuated CLAD phenotype resembling the moderate deficiency phenotype of LAD. The improvement in the CLAD phenotype with very low levels of donor CD18(+) leukocytes correlated with the preferential egress of the CD18(+) neutrophils into extravascular sites. The clinical response with very low levels of donor CD18(+) leukocytes in CLAD supports using this model for testing gene therapy strategies since the low levels of gene-corrected hematopoietic cells expected with hematopoietic gene therapy would likely have a therapeutic effect in CLAD.

Identification of a positive regulatory element in the myelin-specific promoter of the PMP22 gene

Over- and under expression of the 22 kDa peripheral myelin protein (PMP22) results in dysmyelinating peripheral neuropathies, such as Charcot-Marie-Tooth disease type 1A (CMT1A) and hereditary neuropathy, with the liability to pressure palsies (HNPP). Expression of the PMP22 gene is driven by two alternative promoters, P1 and P2, with transcripts originating from P1 associated with peripheral nerve myelination by Schwann cells. Transient transfections of constructs containing P1 (3.5 kb) or P2 (2.5 kb) resulted in high levels of reporter gene expression in the RT4-D6P2T schwannoma cell line. Serial deletions of P1 revealed that region P1-A (-105 to -43), situated upstream of the minimal promoter, contained a positive regulatory element. The 62 bp P1-A region conferred in cis a sevenfold increase in expression of luciferase driven by a heterologous promoter in an orientation-dependent manner. Interspecies comparison of the P1-A region revealed a 98% degree of identity between the human, mouse, and rat sequences. A prominent sequence-dependent DNA-protein complex (C-I) was detected in electrophoretic mobility shift assays with P1-A using RT4-D6P2T nuclear extract and was localized to a minimal 21 bp region within P1-A. Site-directed mutagenesis of this region revealed nucleotides at positions -46 to -43 as being necessary for formation of C-I. Functional analysis of the mutated P1-A element indicated that positions -46 and -45 were essential for transactivation mediated by this element. Characterization of the transacting factor(s) interacting with this key regulatory element will shed light on its role in regulating peripheral nerve myelination.

Competitive binding of triplex-forming oligonucleotides in the two alternate promoters of the PMP22 gene

Overexpression of the 22-kDa peripheral myelin protein (PMP22) causes the inherited peripheral neuropathy, Charcot-Marie-Tooth disease type 1A (CMT1A). In an attempt to alter PMP22 gene expression as a possible therapeutic strategy for CMT1A, antiparallel triplex-forming oligonucleotides (TFO) were designed to bind to purine-rich target sequences in the two PMP22 gene promoters, P1 and P2. Target region I in P1 and region V in P2 were also shown to specifically bind proteins in mammalian nuclear extracts. Competition for binding of these targets by TFO vs. protein(s) was compared by exposing proteins to their target sequences after triplex formation (passive competition) or by allowing TFO and proteins to simultaneously compete for the same targets (active competition). In both formats, TFO were shown to competitively interfere with the binding of protein to region I. Oligonucleotides directed to region V competed for protein binding by a nontriplex-mediated mechanism, most likely via the formation of higher-order, manganese-destabilizable structures. Given that the activity of the P1 promoter is closely linked to peripheral nerve myelination, TFO identified here could serve as useful reagents in the investigation of promoter function, the role of PMP22 in myelination, and possibly as rationally designed drugs for the therapy of CMT1A. The nontriplex-mediated action of TFO directed at the P2 promoter may have wider implications for the use of such oligonucleotides in vivo.

[Simultaneous spectrophotometric determination of trace ferrum and cobalt with 5-Br-PADAP and Tween-80]

A new simultaneous method for the determination of ferrum and cobalt with 5-Br-PADAP by spectrophotometry in the presence of Twen-80 is studied. The results showed that in pH = 3.4 HAc-NaAc buffer medium, ferrum and cobalt can formed colored complexes with 5-Br-PADAP. Its maximum absorption wavelengths are at 585 nm. Beer's law is obeyed for the concentration of ferrum in the range of 0-10 micrograms.25 mL-1 and 0-12 micrograms.25 mL-1 of cobalt. The apparent molar absorptivities are epsilon 585Fe = 7.18 x 10(4) and epsilon 585Co = 9.27 x 10(4) respectively. This method has been applied to the determination of ferrum and cobalt in water sample with satisfactory results.

Esophageal cancer complicated by acute myelofibrosis--report of an autopsy case

An autopsy case of esophageal cancer complicated by myelofibrosis was studied. A 62-year-old Japanese patient with esophageal cancer, received surgical treatment and then splenectomy. The resected spleen was normal in appearance. Five months later he received radiation therapy for the cancer. After the therapy, his blood profile revealed thrombocytopenia and leukoerythroblastosis, and the bone marrow punctures were dry tap. He died of disseminated fungal infections at eleven months after the first operation. An autopsy of the patient revealed a striking increase in the megakaryocytes and a moderate increase in the reticulin fibers in the bone marrow. Myeloid metaplasia was noted in the lymph nodes, kidneys, and other organs and tissues, although the lymph nodes were not grossly swollen. These findings suggest esophageal cancer complicated by acute myelofibrosis. This it the first case report on esophageal cancer complicated by acute myelofibrosis.