Platelets mediate the clearance of senescent red blood cells by forming prophagocytic platelet-cell complexes.

ABSTRACT: In humans, ∼0.1% to 0.3% of circulating red blood cells (RBCs) are present as platelet-RBC (P-RBC) complexes, and it is 1% to 2% in mice. Excessive P-RBC complexes are found in diseases that compromise RBC health (eg, sickle cell disease and malaria) and contribute to pathogenesis. However, the physiological role of P-RBC complexes in healthy blood is unknown. As a result of damage accumulated over their lifetime, RBCs nearing senescence exhibit physiological and molecular changes akin to those in platelet-binding RBCs in sickle cell disease and malaria. Therefore, we hypothesized that RBCs nearing senescence are targets for platelet binding and P-RBC formation. Confirming this hypothesis, pulse-chase labeling studies in mice revealed an approximately tenfold increase in P-RBC complexes in the most chronologically aged RBC population compared with younger cells. When reintroduced into mice, these complexes were selectively cleared from the bloodstream (in preference to platelet-free RBC) through the reticuloendothelial system and erythrophagocytes in the spleen. As a corollary, patients without a spleen had higher levels of complexes in their bloodstream. When the platelet supply was artificially reduced in mice, fewer RBC complexes were formed, fewer erythrophagocytes were generated, and more senescent RBCs remained in circulation. Similar imbalances in complex levels and senescent RBC burden were observed in humans with immune thrombocytopenia (ITP). These findings indicate that platelets are important for binding and clearing senescent RBCs, and disruptions in platelet count or complex formation and clearance may negatively affect RBC homeostasis and may contribute to the known risk of thrombosis in ITP and after splenectomy.

Labelling and optical erasure of synaptic memory traces in the motor cortex.

Dendritic spines are the major loci of synaptic plasticity and are considered as possible structural correlates of memory. Nonetheless, systematic manipulation of specific subsets of spines in the cortex has been unattainable, and thus, the link between spines and memory has been correlational. We developed a novel synaptic optoprobe, AS-PaRac1 (activated synapse targeting photoactivatable Rac1), that can label recently potentiated spines specifically, and induce the selective shrinkage of AS-PaRac1-containing spines. In vivo imaging of AS-PaRac1 revealed that a motor learning task induced substantial synaptic remodelling in a small subset of neurons. The acquired motor learning was disrupted by the optical shrinkage of the potentiated spines, whereas it was not affected by the identical manipulation of spines evoked by a distinct motor task in the same cortical region. Taken together, our results demonstrate that a newly acquired motor skill depends on the formation of a task-specific dense synaptic ensemble.

Absolute energies and emission line shapes of the L x-ray transitions of lanthanide metals.

We use an array of transition-edge sensors, cryogenic microcalorimeters with 4 eV energy resolution, to measure L x-ray emission-line profiles of four elements of the lanthanide series: praseodymium, neodymium, terbium, and holmium. The spectrometer also surveys numerous x-ray standards in order to establish an absolute-energy calibration traceable to the international system of units for the energy range 4 keV to 10 keV. The new results include emission line profiles for 97 lines, each expressed as a sum of one or more Voigt functions; improved absolute energy uncertainty on 71 of these lines relative to existing reference data; a median uncertainty on the peak energy of 0.24 eV, four to ten times better than the median of prior work; and six lines that lack any measured values in existing reference tables. The 97 lines comprise nearly all of the most intense L lines from these elements under broad-band x-ray excitation. The work improves on previous measurements made with a similar cryogenic spectrometer by the use of sensors with better linearity in the absorbed energy and a gold x-ray absorbing layer that has a Gaussian energy-response function. It also employs a novel sample holder that enables rapid switching between science targets and calibration targets with excellent gain balancing. Most of the results for peak energy values shown here should be considered as replacements for the currently tabulated standard reference values, while the line shapes given here represent a significant expansion of the scope of available reference data.

Efficacy and safety findings from DREAM: a phase III study of DHP107 (oral paclitaxel) versus i.v. paclitaxel in patients with advanced gastric cancer after failure of first-line chemotherapy.

Background: Paclitaxel is currently only available as an intravenous (i.v.) formulation. DHP107 is a novel oral formulation of lipid ingredients and paclitaxel. DHP107 demonstrated comparable efficacy, safety, and pharmacokinetics to i.v. paclitaxel as a second-line therapy in patients with advanced gastric cancer (AGC). DREAM is a multicenter, open-label, prospective, randomized phase III study of patients with histologically/cytologically confirmed, unresectable/recurrent AGC after first-line therapy failure. Methods and materials: Patients were randomized 1 : 1 to DHP107 (200 mg/m2 orally twice daily days 1, 8, 15 every 4 weeks) or i.v. paclitaxel (175 mg/m2 day 1 every 3 weeks). Patients were stratified by Eastern Cooperative Oncology Group performance status, disease status, and prior treatment; response was assessed (Response Evaluation Criteria in Solid Tumors) every 6 weeks. Primary end point: non-inferiority of progression-free survival (PFS); secondary end points: overall response rate (ORR), overall survival (OS), and safety. For the efficacy analysis, sequential tests for non-inferiority were carried out, first with a non-inferiority margin of 1.48, then with a margin of 1.25. Results: Baseline characteristics were balanced in the 236 randomized patients (n = 118 per arm). Median PFS (per-protocol) was 3.0 (95% CI 1.7-4.0) months for DHP107 and 2.6 (95% CI 1.8-2.8) months for paclitaxel (hazard ratio [HR] = 0.85; 95% CI 0.64-1.13). A sensitivity analysis on PFS using independent central review showed similar results (HR = 0.93; 95% CI 0.70-1.24). Median OS (full analysis set) was 9.7 (95% CI 7.1 - 11.5) months for DHP107 versus 8.9 (95% CI 7.1-12.2) months for paclitaxel (HR = 1.04; 95% CI 0.76-1.41). ORR was 17.8% for DHP107 (CR 4.2%; PR 13.6%) versus 25.4% for paclitaxel (CR 3.4%; PR 22.0%). Nausea, vomiting, diarrhea, and mucositis were more common with DHP107; peripheral neuropathy was more common with paclitaxel. There were only few Grade≥3 adverse events, most commonly neutropenia (42% versus 53%); febrile neutropenia was reported infrequently (5.9% versus 2.5%). No hypersensitivity reactions occurred with DHP107 (paclitaxel 2.5%). Conclusions: DHP107 as a second-line treatment of AGC was non-inferior to paclitaxel for PFS; other efficacy and safety parameters were comparable. DHP107 is the first oral paclitaxel with proven efficacy/safety for the treatment of AGC. ClinicalTrials.gov: NCT01839773.

NDUFAF3 variants that disrupt mitochondrial complex I assembly may associate with cavitating leukoencephalopathy.

Genetic abnormalities in mitochondrial complex assembling factors are associated with leukoencephalopathy. We present a 1-year-old girl with consciousness disturbance after a respiratory infection. Brain MRI revealed leukoencephalopathy with bilaterally symmetrical hyperintensity in the substantia nigra, medial thalamic nuclei, and basal nuclei, as well as cavities in the cerebral white matter and corpus callosum. Lactate levels in the spinal fluid were high, while magnetic resonance spectroscopy of the cerebral white matter and basal nuclei showed high peak lactate levels, suggesting mitochondrial dysfunction. The respiratory enzyme activity of complex I was reduced to 17% to 21% in skeletal muscle. Whole exome sequencing identified compound heterozygous variations in NDUFAF3, involved in the assembly of mitochondrial complex I (c.342_343insGTG:p.117Valdup, c.505C > A:p.Pro169Thr). Two-dimensional, blue-native polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate-PAGE revealed reductions in Q-module (NDUFS2, NDUFS3, and NDUFA9) and P-module (NDUFB10 and NDUFB11) subunits, indicating disruption of mitochondrial complex I assembly. Our report expands the spectrum of clinical phenotypes associated with pathogenic variants of NDUFAF3.

Folding a small protein using harmonic linear discriminant analysis.

Many processes of scientific importance are characterized by time scales that extend far beyond the reach of standard simulation techniques. To circumvent this impediment, a plethora of enhanced sampling methods has been developed. One important class of such methods relies on the application of a bias that is a function of a set of collective variables specially designed for the problem under consideration. The design of good collective variables can be challenging and thereby constitutes the main bottle neck in the application of these methods. To address this problem, recently we have introduced Harmonic Linear Discriminant Analysis, a method to systematically construct collective variables as linear combinations of a set of descriptors. The method uses input information that can be gathered in short unbiased molecular dynamics simulations in which the system is trapped in the metastable states. Here, to scale up our examination of the method's efficiency, we applied it to the folding of chignolin in water. Interestingly, already before any biased simulations were run, the constructed one-dimensional collective variable revealed much of the physics that underlies the folding process. In addition, using it in metadynamics, we were able to run simulations in which the system goes from the folded state to the unfolded one and back, where to get fully converged results, we combined metadynamics with parallel tempering. Finally, we examined how the collective variable performs when different sets of descriptors are used in its construction.

Ciprofloxacin-induced immune-mediated thrombocytopenia: No cross-reactivity with gemifloxacin.

WHAT IS KNOWN AND OBJECTIVE: Fluoroquinolone-induced immune-mediated thrombocytopenia is uncommon, and no reports of cross-reactivity among fluoroquinolones exist. Here, we describe a case of ciprofloxacin-induced immune thrombocytopenia with no cross-reactivity with gemifloxacin. CASE DESCRIPTION: A 77-year-old woman showed profound thrombocytopenia immediately after two ciprofloxacin injections for pneumonia. Platelet counts recovered rapidly after ciprofloxacin discontinuation. She had experienced thrombocytopenia after ciprofloxacin administration 4 years earlier, which was assumed to be ciprofloxacin-induced immune-related. Interestingly, no thrombocytopenia occurred following the subsequent exposure to another fluoroquinolone, gemifloxacin. WHAT IS NEW AND CONCLUSION: No cross-reactivity occurred between ciprofloxacin and gemifloxacin in this fluoroquinolone-induced immune thrombocytopenia case.

Single-molecule tracking of small GTPase Rac1 uncovers spatial regulation of membrane translocation and mechanism for polarized signaling.

Polarized Rac1 signaling is a hallmark of many cellular functions, including cell adhesion, motility, and cell division. The two steps of Rac1 activation are its translocation to the plasma membrane and the exchange of nucleotide from GDP to GTP. It is, however, unclear whether these two processes are regulated independent of each other and what their respective roles are in polarization of Rac1 signaling. We designed a single-particle tracking (SPT) method to quantitatively analyze the kinetics of Rac1 membrane translocation in living cells. We found that the rate of Rac1 translocation was significantly elevated in protrusions during cell spreading on collagen. Furthermore, combining FRET sensor imaging with SPT measurements in the same cell, the recruitment of Rac1 was found to be polarized to an extent similar to that of the nucleotide exchange process. Statistical analysis of single-molecule trajectories and optogenetic manipulation of membrane lipids revealed that Rac1 membrane translocation precedes nucleotide exchange, and is governed primarily by interactions with phospholipids, particularly PI(3,4,5)P3, instead of protein factors. Overall, the study highlights the significance of membrane translocation in spatial Rac1 signaling, which is in addition to the traditional view focusing primarily on GEF distribution and exchange reaction.

Rapid Remodeling of Invadosomes by Gi-coupled Receptors: DISSECTING THE ROLE OF Rho GTPases.

Invadosomes are actin-rich membrane protrusions that degrade the extracellular matrix to drive tumor cell invasion. Key players in invadosome formation are c-Src and Rho family GTPases. Invadosomes can reassemble into circular rosette-like superstructures, but the underlying signaling mechanisms remain obscure. Here we show that Src-induced invadosomes in human melanoma cells (A375M and MDA-MB-435) undergo rapid remodeling into dynamic extracellular matrix-degrading rosettes by distinct G protein-coupled receptor agonists, notably lysophosphatidic acid (LPA; acting through the LPA1 receptor) and endothelin. Agonist-induced rosette formation is blocked by pertussis toxin, dependent on PI3K activity and accompanied by localized production of phosphatidylinositol 3,4,5-trisphosphate, whereas MAPK and Ca(2+) signaling are dispensable. Using FRET-based biosensors, we show that LPA and endothelin transiently activate Cdc42 through Gi, concurrent with a biphasic decrease in Rac activity and differential effects on RhoA. Cdc42 activity is essential for rosette formation, whereas G12/13-mediated RhoA-ROCK signaling suppresses the remodeling process. Our results reveal a Gi-mediated Cdc42 signaling axis by which G protein-coupled receptors trigger invadosome remodeling, the degree of which is dictated by the Cdc42-RhoA activity balance.

Comparison of the characteristics of Mycobacterium tuberculosis isolates from sputum and lung lesions in chronic tuberculosis patients.

Mycobacterium tuberculosis (Mtb) in sputum originates from lung cavities in tuberculosis (TB) patients. But drug susceptibility testing (DST) of sputum Mtb can not be conducted the same as in the lung because mutagenesis of bacilli may be happening in the lung during treatment and result in the possibility of the presence of heterogeneous drug-resistant subpopulations in the different lung lesions. This could be one of the reasons for low cure rates for multi-drug resistant (MDR)-TB. We studied the resected lungs of nine surgery patients with chronic TB. The isolates isolated from the sputum and different lung lesions of each patient were tested for phenotypic DST and genotyped using restriction fragment length polymorphism (RFLP) typing method. Genetic analysis to resistance to first and second line drugs was also performed. Five of nine patients were MDR-TB and three XDR-TB. DST results for ten anti-TB drugs were in accordance among different lung lesions in eight patients. However, only three of these eight patients showed the concordance of DST with sputum. Even though the isolates were heteroresistant, genotyping them by RFLP showed the clonal population in each individual patient. Six of eight followed-up patients achieved successful cure. In conclusion, the heteroresistance between sputum and lung lesions and a clonal population without mixed infection might provide useful information in establishing treatment regimen and surgery decision for MDR- and XDR-TB.

Morphometric analysis of the maxillary root apex positions according to crowding severity.

OBJECTIVES: To determine differences in arch forms derived from the root apices locations between individuals with <2 mm maxillary crowding and controls. SETTING AND SAMPLE POPULATION: The Department of Orthodontics, Pusan National University. Cone-beam computed tomography (CBCT) images of 102 patients in the control group and 95 patients in the crowding group. MATERIALS AND METHODS: X, Y and Z coordinates of the tip of the crowns and the apex of the root of the maxillary teeth (except second molars) were determined on the CBCT images. The acquired three-dimensional (3D) coordinates were converted into two-dimensional (2D) coordinates via projection on the palatal plane, and the Procrustes analysis was employed to process the converted 2D coordinates. The mean shape of the arch form derived from the location of the tip of the crowns and the apex of the root was compared between groups using the statistical shape analysis. RESULTS: There was a statistically significant difference (P = .046) between the groups for the mean shape of the root apex arch form, but the difference was small and clinically irrelevant as it is minor compared to the degree of crowding. CONCLUSIONS: Maxillary arch from at the level of the maxillary apices only shows minor differences between crowded and non-crowded dentitions.

[Vitiligo occurring on dermal melanocytosis (nevus of Ota) in a dark-skinned patient]. / Vitiligo dévéloppé sur une mélanocytose dermique (nævus de Ota) chez une patiente à peau foncée.

BACKGROUND: Nevus of Ota is a rare disease most frequently found in Asians. It presents clinically as a bluish gray hyperpigmentation of one side of the face. Transformation into melanoma and glaucoma are the main risks. The appearance of vitiligo lesions with poliosis within a nevus of Ota is exceptional. PATIENTS AND METHODS: A 22-year-old female patient with a nevus of Ota consulted for depigmentation of the eyelashes. Physical examination revealed hyperpigmentation in the right orbitofrontal part of her face, achromic macules and eyelash poliosis. A diagnosis was made of vitiligo developing on a nevus of Ota. Ophthalmologic examination showed hyperpigmentation of the sclera. Regular dermatologic and ophthalmologic follow-up was instituted. DISCUSSION: Vitiligo is a condition characterized by the development of depigmented lesions secondary to chronic degradation of the melanocytes of the epidermis and the follicles. Its occurrence on congenital nevus and melanoma has already been reported. However, its appearance in dermal melanocytosis is very rare. Since the first observation of this association in 1979, only 4 other cases have been reported. The pathogenic mechanisms of this association are still poorly understood. Histopathological examination generally shows a loss of epidermal melanocytes, especially in the basal layer, while dermal melanocytes remain unaffected. In this context, vitiligo developed on dermal melanosis appears to result from the difference between the properties of normal (epidermal) melanocytes and ectopic (dermal) melanocytes. CONCLUSION: Association of vitiligo with nevus of Ota is rare. Herein, we report a new case in a dark-skinned subject.

[Umbilical endometriosis mimicking a keloid in a young black woman: A case report]. / Endométriose ombilicale simulant une chéloïde chez une patiente à peau foncée.

BACKGROUND: Most umbilical tumors are diagnosed as benign tumors, umbilical metastases of abdominal and pelvic tumors, or Sister Marie Joseph nodule. Herein, we report a case of cutaneous umbilical endometriosis mistaken for a keloid. PATIENTS AND METHODS: A young black woman aged 26 consulted for a painful umbilical tumefaction. She had noted the appearance of a nodule of the umbilicus 10 months ago with bleeding during her menstrual periods. Skin examination revealed a firm and painful umbilical nodule 2.5cm in diameter. She was treated with corticosteroid injections for one month for umbilical keloid. Given that the symptoms recurred regularly at the time of menstruation, we suspected umbilical endometriosis. This diagnosis was finally confirmed by histopathological examination and hormone therapy was instituted on gynecological advice before scheduled surgical excision. CONCLUSION: In a setting of an umbilical tumor simulating a keloid associated with cyclical symptoms in a black woman, the diagnosis of umbilical endometriosis should not be overlooked by the dermatologist.

ABO-Incompatible Adult Living Donor Liver Transplantation Under the Desensitization Protocol With Rituximab.

ABO incompatibility is no longer considered a contraindication for adult living donor liver transplantation (ALDLT) due to various strategies to overcome the ABO blood group barrier. We report the largest single-center experience of ABO-incompatible (ABOi) ALDLT in 235 adult patients. The desensitization protocol included a single dose of rituximab and total plasma exchange. In addition, local graft infusion therapy, cyclophosphamide, or splenectomy was used for a certain time period, but these treatments were eventually discontinued due to adverse events. There were three cases (1.3%) of in-hospital mortality. The cumulative 3-year graft and patient survival rates were 89.2% and 92.3%, respectively, and were comparable to those of the ABO-compatible group (n = 1301). Despite promising survival outcomes, 17 patients (7.2%) experienced antibody-mediated rejection that manifested as diffuse intrahepatic biliary stricture; six cases required retransplantation, and three patients died. ABOi ALDLT is a feasible method for expanding a living liver donor pool, but the efficacy of the desensitization protocol in targeting B cell immunity should be optimized.

Different X-linked KDM5C mutations in affected male siblings: is maternal reversion error involved?

Genetic reversion is the phenomenon of spontaneous gene correction by which gene function is partially or completely rescued. However, it is unknown whether this mechanism always correctly repairs mutations, or is prone to error. We investigated a family of three boys with intellectual disability, and among them we identified two different mutations in KDM5C, located at Xp11.22, using whole-exome sequencing. Two affected boys have c.633delG and the other has c.631delC. We also confirmed de novo germline (c.631delC) and low-prevalence somatic (c.633delG) mutations in their mother. The two mutations are present on the same maternal haplotype, suggesting that a postzygotic somatic mutation or a reversion error occurred at an early embryonic stage in the mother, leading to switched KDM5C mutations in the affected siblings. This event is extremely unlikely to arise spontaneously (with an estimated probability of 0.39-7.5 × 10(-28) ), thus a possible reversion error is proposed here to explain this event. This study provides evidence for reversion error as a novel mechanism for the generation of somatic mutations in human diseases.

The brain-derived neurotrophic factor Val66Met polymorphism and degeneration of the corticospinal tract after stroke: a diffusion tensor imaging study.

BACKGROUND AND PURPOSE: A common single nucleotide polymorphism, Val66Met, in the human brain-derived neurotrophic factor (BDNF) gene has a potential role in the pathogenesis and treatment of stroke. The relevance of the BDNF Val66Met polymorphism to long-term stroke outcomes was examined, specifically with respect to changes in corticospinal integrity. METHODS: Thirty-five stroke patients with unilateral motor weakness were genotyped within 2 weeks after onset (T1), and changes in the integrity of the ipsilesional corticospinal tract (CST) as well as alterations in motor function at 1 month (T2) and 3 months after onset (T3) were tracked. RESULTS: On the basis of the Fugl-Meyer assessment upper extremity score, carriers of the Met allele (Val/Met and Met/Met) showed poorer motor outcomes at T2 and T3 compared to carriers of only the Val allele (Val/Val). For both BDNF allele types, patients exhibited characteristic degeneration of the CST compared to healthy controls. There were no differences between the two genotypes with respect to time-dependent changes in diffusion-tensor-imaging-derived parameters of the CST. However, the two groups showed different relationships between motor outcomes and directional diffusivities according to the elapsed time after onset. Poorer motor function was associated with lower axial diffusivity values for the Val/Val genotype group in the sub-acute phase (T1 and T2) but with higher radial diffusivity values for the Val/Met and Met/Met genotype group in the early chronic phase (T3). CONCLUSIONS: Motor recovery in stroke patients may be affected by the BDNF Val66Met polymorphism, possibly through its effects on distinct pathological processes underlying corticospinal degeneration.

Effect of stress hyperglycemia and intensive rehabilitation therapy in non-diabetic hemorrhagic stroke: Korean Stroke Cohort for Functioning and Rehabilitation.

BACKGROUND AND PURPOSE: We investigated the effect of stress hyperglycemia on the functional outcomes of non-diabetic hemorrhagic stroke. In addition, we investigated the usefulness of intensive rehabilitation for improving functional outcomes in patients with stress hyperglycemia. METHODS: Non-diabetic hemorrhagic stroke patients were recruited and divided into two groups: intracerebral hemorrhage (ICH) (n = 165) and subarachnoid hemorrhage (SAH) (n = 156). Each group was divided into non-diabetics with or without stress hyperglycemia. Functional assessments were performed at 7 days and 3, 6 and 12 months after stroke onset. The non-diabetic with stress hyperglycemia groups were again divided into two groups who either received or did not receive intensive rehabilitation treatment. Serial functional outcome was compared between groups. RESULTS: For the ICH group, patients with stress hyperglycemia had worse modified Rankin Scale, National Institutes of Health Stroke Scale, Functional Ambulatory Category and Korean Mini-Mental State Examination scores than patients without stress hyperglycemia. For the SAH group, patients with stress hyperglycemia had worse scores on all functional assessments than patients without stress hyperglycemia at all time-points. After intensive rehabilitation treatment of patients with stress hyperglycemia, the ICH group had better scores on Functional Ambulatory Category and the SAH group had better scores on all functional assessments than patients without intensive rehabilitation treatment. CONCLUSIONS: Stress hyperglycemia affects the long-term prognosis of non-diabetic hemorrhagic stroke patients. Among stress hyperglycemia patients, intensive rehabilitation can enhance functional improvement after stroke.