Complex formation of immunoglobulin superfamily molecules Side-IV and Beat-IIb regulates synaptic specificity

Neurons establish specific synapses based on the adhesive properties of cell-surface proteins while also retaining the ability to form synapses in a relatively non-selective manner. However, comprehensive understanding of the underlying mechanism reconciling these opposing characteristics remains incomplete. Here, we have identified Side-IV/Beat-IIb, members of the Drosophila immunoglobulin superfamily, as a combination of cell-surface recognition molecules inducing synapse formation. The Side-IV/Beat-IIb combination transduces bifurcated signaling with Side-IV's co-receptor, Kirre, and a synaptic scaffold protein, Dsyd-1. Genetic experiments and subcellular protein localization analyses showed the Side-IV/Beat-IIb/Kirre/Dsyd-1 complex to have two essential functions. First, it narrows neuronal binding specificity through Side-IV/Beat-IIb extracellular interactions. Second, it recruits synapse formation factors, Kirre and Dsyd-1, to restrict synaptic loci and inhibit miswiring. This dual function explains how the combinations of cell-surface molecules enable the ranking of preferred interactions among neuronal pairs to achieve synaptic specificity in complex circuits in vivo.

High-power laser experiment forming a supercritical collisionless shock in a magnetized uniform plasma at rest

We present an experimental method to generate quasiperpendicular supercritical magnetized collisionless shocks. In our experiment, ambient nitrogen (N) plasma is at rest and well magnetized, and it has uniform mass density. The plasma is pushed by laser-driven ablation aluminum (Al) plasma. Streaked optical pyrometry and spatially resolved laser collective Thomson scattering clarify structures of plasma density and temperatures, which are compared with one-dimensional particle-in-cell simulations. It is indicated that just after the laser irradiation, the Al plasma is magnetized by a self-generated Biermann battery field, and the plasma slaps the incident N plasma. The compressed external field in the N plasma reflects N ions, leading to counterstreaming magnetized N flows. Namely, we identify the edge of the reflected N ions. Such interacting plasmas form a magnetized collisionless shock.

Direct detection of circular polarized light in helical 1D perovskite-based photodiode

Detection of circularly polarized light (CPL) has a high potential for development of various optical technologies. Conventional photodetectors require optical polarizers on the device to detect polarized light, and this causes substantial losses of sensitivity and resolution in light detection. Here, we report direct CPL detection by a photodiode using a helical one-dimensional (1D) structure of lead halide perovskites composed of naphthylethylamine-based chiral organic cations. The 1D structure with face-sharing (PbI₆)^4- octahedral chains whose helicity is largely affected by chiral cations shows intense circular dichroism (CD) signals over 3000 mdeg at 395 nm with the highly anisotropy factor (g _CD) of 0.04. This high CD enables photocurrent detection with effective discrimination between left-handed and right-handed CPLs. The CPL detector based on this 1D perovskite achieved the highest polarization discrimination ratio of 25.4, which largely surpasses the direct detecting CPL devices (<4) using chiral plasmonic metamaterials and organic materials.

Surgical options in suprastomal collapse-induced severe airway obstruction

Purpose

A single institutions experience with various surgical options in the treatment of severe suprastomal collapse (SSC).

Methods

The study included 18 tracheostomized children with SSC treated between January 2012 and December 2018. Data included: patient demography, initial airway lesions, comorbidities, indication and age at tracheostomy, prior airway surgery, stomal demography, type of surgery, postoperative management, complications and treatment outcomes.

Results

Four techniques were used to correct SSC. The surgical choice was dependent on stoma demography and associated airway lesions. Excision was done in eight patients and rib cartilage augmentation in five. Three patients had single stage tracheal resection and anastomosis. Two patients received stomal rigidification and temporary placement of Montgomery T tube. Three patients with anterior rib graft augmentation required additional lateral tracheal wall rigidification. Three patients (two with cartilage augmentation, and one with stomal rigidification) developed minimal granulation tissue in the postoperative period. Complete SSC resolution was seen in all except two patients who had a partial response to the treatment. All patients were successful decannulated and are currently asymptomatic.

Conclusion

Decannulation failures may be due to severe suprastomal collapse that could be either unique or associated with obstructing laryngotracheal lesions. Therefore, it is essential to select the most appropriate surgical treatment to obtain overall favorable outcomes.

Electronic supplementary material

The online version of this article (10.1007/s00405-020-06339-3) contains supplementary material, which is available to authorized users.

Serum Wisteria floribunda agglutinin-positive Mac-2-binding protein for patients with chronic hepatitis B and C: a comparative study

We compared Wisteria floribunda agglutinin-positive Mac-2-binding protein (WFA⁺ -M2BP) levels between patients with chronic hepatitis B (n=249) and chronic hepatitis C (n=386) based on the degree of liver fibrosis. We examined WFA⁺ -M2BP levels in patients with F4 (cirrhosis), F3 or more (advanced fibrosis) and F2 or more (significant fibrosis) in the two groups. We further examined the relationship between five fibrosis markers and the degree of fibrosis. The WFA⁺ -M2BP values ranged from 0.25 cut-off index (COI) to 12.9 COI in patients with hepatitis B and 0.34-20.0 COI in patients with hepatitis C (P<.0001). The median WFA⁺ -M2BP values in F4 in the two groups were 2.83 COI in patients with hepatitis B and 5.03 COI in patients with hepatitis C (P=.0046). The median WFA⁺ -M2BP values in F3 or more in the two groups were 1.79 COI in patients with hepatitis B and 3.79 COI in patients with hepatitis C (P<.0001). The median WFA⁺ -M2BP values in F2 or more in the two groups were 1.49 COI in the hepatitis B cohort and 3.19 COI in the hepatitis C group (P<.0001). Among five liver fibrosis markers, WFA⁺ -M2BP had the highest correlation coefficient (r_s =.629) in terms of correlation with the degree of fibrosis in the patients with hepatitis C and had the second highest r_s value (.415) in the hepatitis B group. Although WFA⁺ -M2BP could be a useful indicator of liver fibrosis, WFA⁺ -M2BP levels in the two groups significantly differed even in the same degree of fibrosis. Individual cut-off values in each aetiology for the degree of fibrosis should be determined.

Improvement of neurological disorders in postmenopausal model rats by administration of royal jelly

OBJECTIVE

Royal jelly (RJ) from honeybees (Apis mellifera) has estrogenic activity. Estrogen deficiency after menopause leads to a high risk of memory impairment and depression as well as metabolic syndrome and osteoporosis. We here investigated the effect of RJ on memory impairment and depression-like behaviors in ovariectomized (OVX) rats.

METHODS

OVX rats were administered with RJ for 82 days. Hippocampus-dependent spatial memory and depression-like behaviors were assessed by the Morris water maze test and the forced swimming test, respectively. The weights of body, brain and uterus and the contents of protein and myelin galactolipids including galactosylceramide and sulfatide were measured.

RESULTS

Memory impairment and depression-like behaviors in OVX rats were recovered to the levels of sham-operated rats by RJ administration. Increased body weight and decreased uterine weight in OVX rats were recovered to the levels of sham-operated rats by 17β-estradiol (E2) administration but not by RJ administration. In contrast, brain weight was slightly increased by RJ administration but not by E2 administration. The contents of protein and myelin galactolipids were higher in the brains of RJ-administered OVX rats than in the brains of E2-administered OVX rats.

CONCLUSION

The results suggest that RJ has a beneficial effect on neurological symptoms of a menopausal disorder.

Gate-Tunable Atomically Thin Lateral MoS2 Schottky Junction Patterned by Electron Beam

Among atomically thin two-dimensional (2D) materials, molybdenum disulfide (MoS2) is attracting considerable attention because of its direct bandgap in the 2H-semiconducting phase. On the other hand, a 1T-metallic phase has been revealed, bringing complementary application. Recently, thanks to top-down fabrication using electron beam (EB) irradiation techniques, in-plane 1T-metal/2H-semiconductor lateral (Schottky) MoS2 junctions were demonstrated, opening a path toward the co-integration of active and passive two-dimensional devices. Here, we report the first transport measurements evidencing the formation of a MoS2 Schottky barrier (SB) junction with barrier height of 0.13-0.18 eV created at the interface between EB-irradiated (1T)/nonirradiated (2H) regions. Our experimental findings, supported by state-of-the-art simulation, reveal unique device fingerprint of SB-based field-effect transistors made from atom-thin 1T layers.

Electric-Field Induced Activation of Dark Excitonic States in Carbon Nanotubes

Electrical activation of optical transitions to parity-forbidden dark excitonic states in individual carbon nanotubes is reported. We examine electric-field effects on various excitonic states by simultaneously measuring photocurrent and photoluminescence. As the applied field increases, we observe an emergence of new absorption peaks in the excitation spectra. From the diameter dependence of the energy separation between the new peaks and the ground state of E11 excitons, we attribute the peaks to the dark excited states which became optically active due to the applied field. Field-induced exciton dissociation can explain the photocurrent threshold field, and the edge of the E11 continuum states has been identified by extrapolating to zero threshold.

Gate-controlled generation of optical pulse trains using individual carbon nanotubes

In single-walled carbon nanotubes, electron–hole pairs form tightly bound excitons because of limited screening. These excitons display a variety of interactions and processes that could be exploited for applications in nanoscale photonics and optoelectronics. Here we report on optical pulse-train generation from individual air-suspended carbon nanotubes under an application of square-wave gate voltages. Electrostatically induced carrier accumulation quenches photoluminescence, while a voltage sign reversal purges those carriers, resetting the nanotubes to become luminescent temporarily. Frequency-domain measurements reveal photoluminescence recovery with characteristic frequencies that increase with excitation laser power, showing that photoexcited carriers provide a self-limiting mechanism for pulsed emission. Time-resolved measurements directly confirm the presence of an optical pulse train synchronized to the gate voltage signal, and flexible control over pulse timing and duration is also demonstrated. These results identify an unconventional route for optical pulse generation and electrical-to-optical signal conversion, opening up new prospects for controlling light at the nanoscale.

The photocurrent and luminescence of carbon nanotubes is governed by excitonic processes with diverse uses in nano-photonics. Here, Jiang et al. generate optical pulses from individual air-suspended carbon nanotubes under an application of square-wave gate voltages with control over pulse timing and duration.

Ultralow mode-volume photonic crystal nanobeam cavities for high-efficiency coupling to individual carbon nanotube emitters

The unique emission properties of single-walled carbon nanotubes are attractive for achieving increased functionality in integrated photonics. In addition to being room-temperature telecom-band emitters that can be directly grown on silicon, they are ideal for coupling to nanoscale photonic structures. Here we report on high-efficiency coupling of individual air-suspended carbon nanotubes to silicon photonic crystal nanobeam cavities. Photoluminescence images of dielectric- and air-mode cavities reflect their distinctly different mode profiles and show that fields in the air are important for coupling. We find that the air-mode cavities couple more efficiently, and estimated spontaneous emission coupling factors reach a value as high as 0.85. Our results demonstrate advantages of ultralow mode-volumes in air-mode cavities for coupling to low-dimensional nanoscale emitters.

Spontaneous exciton dissociation in carbon nanotubes

Simultaneous photoluminescence and photocurrent measurements on individual single-walled carbon nanotubes reveal spontaneous dissociation of excitons into free electron-hole pairs. The correlation of luminescence intensity and photocurrent shows that a significant fraction of excitons are dissociating before recombination. Furthermore, the combination of optical and electrical signals also allows for extraction of the absorption cross section and the oscillator strength. Our observations explain the reasons why photoconductivity measurements in single-walled carbon nanotubes are straightforward despite the large exciton binding energies.

Positions of Q(A)and Chl(Z)Relative to Tyrosine Y(Z)and Y(D)in Photosystem II Studied by Pulsed EPR

PELDOR (Pulsed Electron eLectron DOuble Resonance) was applied to determinethe distance of between Y(Z)and Q(A) (-)inY(D)-less mutant of Chlamydomonas reinhardtiiin Tris-treatedand Zn-substituted preparation of photosystem II. The value of distance wasfound to be 34.5 ± 1 Â. A '2+1' electron spin echo method has beenapplied to measure the orientation of the radius-vector RfomY(D)to Chl(Z)in a membrane-oriented photosystem II. The anglebetween Rand the membrane normal nwas determined to be 50 ±5(°), using the distance 29.4 ± 0.5 Â determined in non-orientedPS II.

Campylobacter bacteremia in hemodialysis patients by eating raw meat - the importance of sanitary education

In 2011, simultaneous, widespread outbreaks of food poisoning by contaminated enterohemorrhagic Escherichia coli in beef, which killed four and hospitalized more than 30 people, occurred in Japan. While the press was widely reporting this disaster, two maintenance hemodialysis patients were suffering from Campylobacter bacteremia by eating undercooked meat. One patient was infected with C. upsaliensis and the other with C. fetus. Although these patients could be successfully treated, they led us to consider the characteristics of C. upsaliensis and C. fetus as opportunistic pathogens, as well as changes in dietary behaviors and food markets. Moreover, they emphasized the need for hemodialysis patients to be not only educated in that they should restrict potassium, phosphate and water intake, but also that they should take care of food sanitation.

Effect of (6R)- and (6S)-tetrahydrobiopterin on L-3,4-dihydroxyphenylalanine (DOPA) formation in NRK fibroblasts transfected with human tyrosine hydroxylase type 2 cDNA

l-erythro-5,6,7,8-Tetrahydrobiopterin (BH(4)), which is the cofactor of aromatic amino acid hydroxylases, plays an important role in the biosyntheses of monoamine neurotransmitters. BH(4) exists as natural (6R)- and unnatural (6S)-isomers. In our previous reports, only (6R)-isomer significantly stimulated cofactor activity for tyrosine, tryptophan and phenylalanine hydroxylases (TH, TPH, PAH) in whole animals or in tissue slices. In this study we have compared the in situ cofactor activity on TH between natural (6R)- and unnatural (6S)-isomers in clonal cells. We have transfected human TH type 2 cDNA into the normal rat kidney (NRK) fibroblasts. These cells expressed TH protein, but had neither DOPA decarboxylase (DDC) nor BH(4). Thus, TH activity was observed only in the presence of exogenous BH(4). We compared the difference in in situ DOPA formation by TH activity in the presence of (6R)- or (6S)-BH(4) in the human TH-transfected cells. The effect of exogenous BH(4) was also compared between (6R)- and (6S)-isomers in rat pheochromocytoma PC12h cells, which contained approximately 100 ?M endogenous (6R)-BH(4). The rate of uptake of both BH(4) isomers into these cells increased in proportion to the pterin cofactor concentrations in the incubation medium up to 400 ?M but was nearly saturated at 1 mM BH(4). TH-transfected NRK fibroblasts formed DOPA only in the presence of exogenously added (6R)- or (6S)-BH(4) dose-dependently and released DOPA into the medium. At a saturating concentration of 1 mM, (6R)-BH(4) was approximately three times as active as (6S)-BH(4). In contrast, in PC12h cells which contained endogenous (6R)-BH(4) (approximately 100 ?M), exogenous (6R)-BH(4) activated DOPA formation maximally at 500 ?M about 10-fold, while (6S)-BH(4) activated it only slightly, about 2.5-fold. These results suggest that (6S)-isomer has lower cofactor activity with TH in the cells than (6R)-isomer. This TH transfected fibroblasts should be useful to assess cofactor activities of tetrahydropteridines in the cell.

Exacerbation of diabetic nephropathy by hyperlipidaemia is mediated by Toll-like receptor 4 in mice

AIMS/HYPOTHESIS

Hyperlipidaemia is an independent risk factor for the progression of diabetic nephropathy, but its molecular mechanism remains elusive. We investigated in mice how diabetes and hyperlipidaemia cause renal lesions separately and in combination, and the involvement of Toll-like receptor 4 (TLR4) in the process.

METHODS

Diabetes was induced in wild-type (WT) and Tlr4 knockout (KO) mice by intraperitoneal injection of streptozotocin (STZ). At 2 weeks after STZ injection, normal diet was substituted with a high-fat diet (HFD). Functional and histological analyses were carried out 6 weeks later.

RESULTS

Compared with treatment with STZ or HFD alone, treatment of WT mice with both STZ and HFD markedly aggravated nephropathy, as indicated by an increase in albuminuria, mesangial expansion, infiltration of macrophages and upregulation of pro-inflammatory and extracellular-matrix-associated gene expression in glomeruli. In Tlr4 KO mice, the addition of an HFD to STZ had almost no effects on the variables measured. Production of protein S100 calcium binding protein A8 (calgranulin A; S100A8), a potent ligand for TLR4, was observed in abundance in macrophages infiltrating STZ-HFD WT glomeruli and in glomeruli of diabetic nephropathy patients. High-glucose and fatty acid treatment synergistically upregulated S100a8 gene expression in macrophages from WT mice, but not from KO mice. As putative downstream targets of TLR4, phosphorylation of interferon regulatory factor 3 (IRF3) was enhanced in kidneys of WT mice co-treated with STZ and HFD.

CONCLUSIONS/INTERPRETATION

Activation of S100A8/TLR4 signalling was elucidated in an animal model of diabetic glomerular injury accompanied with hyperlipidaemia, which may provide novel therapeutic targets in progressive diabetic nephropathy.

Evaluation of CT angiography for visualisation of the lenticulostriate artery: difference between normotensive and hypertensive patients

OBJECTIVE

High-resolution CT angiography (CTA) is currently available using multidetector row CT (MDCT); however, its use for small artery visualisation has been limited. To evaluate its capability, we investigated CTA visualisation for difference in number of the lenticulostriate artery (LSA) branches between normotensive and hypertensive patients, because hypertension is a major cause of LSA damage.

METHODS

This was a retrospective study evaluating cerebrovascular CTA at our hospital conducted from February 2008 to June 2009 under approval of the institutional review board. 117 patients (39 males and 78 females, 19-88 years old) were included. CTA was conducted using a 64 channel MDCT. Total numbers of LSA branches were examined for differences by age with regression analysis and the presence or absence of hypertension and/or aneurysm using two-sample t-tests. A p-value <0.016 was considered statistically significant after correction for multiple comparisons. A multiple variable analysis of three factors was also conducted.

RESULTS

The average number of LSA branches was 3.6 [95% confidence interval (CI) 3.0-4.1] and 4.4 (95% CI 4.1-4.7), respectively, for a patient with and without history of hypertension, and the difference was statistically significant (p=0.013). The difference was approximately one branch in the multiple variable analysis. No significant correlation was observed for age and no significant difference was observed for the presence or absence of aneurysms.

CONCLUSIONS

Contrast-enhanced CTA can visualise significant differences in the number of LSA branches among patients with and without hypertension. Advances in knowledge Current high-resolution CTA can visualise LSA well, which enables finding a difference in the LSA between normotensive subjects and hypertensive patients.

Ultraselective transcatheter infusion of epirubicin in water-in-oil-in-water emulsion for small hepatocellular carcinoma

OBJECTIVE

We have previously reported the clinical efficacy of water-in-oil-in-water (W/O/W) emulsions, particularly for non-selective transcatheter arterial infusion (TAI) therapy. W/O/W emulsions limit damage to normal hepatic parenchyma, because of their minimal embolic effect on peripheral arteries and slow release of anticancer agent. The purpose of this study was to evaluate the safety and effectiveness of ultraselective TAI (UTI) of a W/O/W emulsion for hepatocellular carcinoma (HCC).

METHODS

11 patients with Stage I-III small HCCs (<5 cm) underwent UTI with a W/O/W emulsion at our institute. Response was assessed using the Response Evaluation Criteria in Solid Tumors. Disease-free survival time was estimated using the Kaplan-Meier method.

RESULTS

All 10 patients, excluding a patient who underwent a hepatectomy after UTI, achieved complete response. The 6, 12 and 30 month cumulative disease-free survival rates for the 10 patients were 100%, 90% and 60%, respectively. The patient who underwent hepatectomy after UTI developed complete necrosis of the HCC and peritumoral non-tumorous liver parenchyma.

CONCLUSION

UTI therapy using a W/O/W emulsion for patients with small HCCs results in a good local response.