A repeating fast radio burst associated with a persistent radio source.

The dispersive sweep of fast radio bursts (FRBs) has been used to probe the ionized baryon content of the intergalactic medium1, which is assumed to dominate the total extragalactic dispersion. Although the host-galaxy contributions to the dispersion measure appear to be small for most FRBs2, in at least one case there is evidence for an extreme magneto-ionic local environment3,4 and a compact persistent radio source5. Here we report the detection and localization of the repeating FRB 20190520B, which is co-located with a compact, persistent radio source and associated with a dwarf host galaxy of high specific-star-formation rate at a redshift of 0.241 ± 0.001. The estimated host-galaxy dispersion measure of approximately [Formula: see text] parsecs per cubic centimetre, which is nearly an order of magnitude higher than the average of FRB host galaxies2,6, far exceeds the dispersion-measure contribution of the intergalactic medium. Caution is thus warranted in inferring redshifts for FRBs without accurate host-galaxy identifications.

Deep brain stimulation therapy for Parkinson's disease using frameless stereotaxy: comparison with frame-based surgery.

BACKGROUND AND PURPOSE: Deep brain stimulation (DBS) surgery has been performed using frame-based stereotaxy traditionally; however, in recent years, it has also been performed using frameless stereotaxy. The purpose of this study was to compare the experience at our centre in performing DBS surgery using frameless surgery for patients with Parkinson's disease with that of using frame-based surgery. METHODS: Twenty-four patients with advanced Parkinson's disease underwent DBS surgery, 12 with frameless and 12 with frame-based stereotaxy. After identifying the subthalamus by microelectrode recording (MER), the DBS electrodes were implanted and connected to an implanted programmable generator in all patients. Programming was started 1 month after the operation and the outcome of the patients was followed up regularly for at least 12 months. RESULTS: After 1 year of follow-up, the patients who received frameless surgery showed no difference in the degree of improvement in clinical motor function compared with the patients who received frame-based surgery (P = 0.819); the average improvement was 60.9% and 56.9%, respectively, in the stimulation alone/medication-off state, as evaluated by the Unified Parkinson's Disease Rating Scale-III motor subscore. However, the frameless group had significantly shorter total MER time (P = 0.0127) and a smaller number of trajectories (P = 0.0096) than the frame-based group. CONCLUSIONS: Our data indicate that frameless DBS surgery has a similar outcome when compared with frame-based surgery; however, frameless surgery can decrease the operation time, MER time, and MER trajectory number.

Drosophila melanogaster mounts a unique immune response to the Rhabdovirus sigma virus.

Rhabdoviruses are important pathogens of humans, livestock, and plants that are often vectored by insects. Rhabdovirus particles have a characteristic bullet shape with a lipid envelope and surface-exposed transmembrane glycoproteins. Sigma virus (SIGMAV) is a member of the Rhabdoviridae and is a naturally occurring disease agent of Drosophila melanogaster. The infection is maintained in Drosophila populations through vertical transmission via germ cells. We report here the nature of the Drosophila innate immune response to SIGMAV infection as revealed by quantitative reverse transcription-PCR analysis of differentially expressed genes identified by microarray analysis. We have also compared and contrasted the immune response of the host with respect to two nonenveloped viruses, Drosophila C virus (DCV) and Drosophila X virus (DXV). We determined that SIGMAV infection upregulates expression of the peptidoglycan receptor protein genes PGRP-SB1 and PGRP-SD and the antimicrobial peptide (AMP) genes Diptericin-A, Attacin-A, Attacin-B, Cecropin-A1, and Drosocin. SIGMAV infection did not induce PGRP-SA and the AMP genes Drosomycin-B, Metchnikowin, and Defensin that are upregulated in DCV and/or DXV infections. Expression levels of the Toll and Imd signaling cascade genes are not significantly altered by SIGMAV infection. These results highlight shared and unique aspects of the Drosophila immune response to the three viruses and may shed light on the nature of the interaction with the host and the evolution of these associations.

Transmission of grapevine leafroll-associated virus 3 by the vine mealybug (Planococcus ficus).

Grapevine leafroll disease is caused by grapevine leafroll-associated viruses (GLRaVs). Within this virus complex, GLRaV-3 is the predominant species in the world. Several GLRaVs have been shown to be transmitted from vine to vine by mealybugs although a detailed characterization of transmission biology is lacking. The introduction of the vine mealybug (Planococcus ficus) in California and other regions of the world may result in increasing disease incidence of established GLRaVs. We studied the characteristics of GLRaV-3 transmission by the vine mealybug. Our results indicate that the vine mealybug transmits GLRaV-3 in a semipersistent manner. First instars were more efficient vectors than adult mealybugs. GLRaV-3 transmission lacked a latent period in the vector. Virus transmission occurred with a 1-h acquisition access period (AAP) and peaked with a 24-h AAP. Mealybugs inoculated GLRaV-3 with a 1-h inoculation access period (IAP), and transmission efficiency increased with longer plant access period up to 24 h, after which transmission rate remained constant. After an AAP of 24 h, mealybugs lost GLRaV-3 and infectivity 4 days after virus acquisition. In addition, GLRaV-3 was not transovarially transmitted from infected females to their progeny as detected by reverse transcription polymerase chain reaction. In summary, we systematically analyzed transmission parameters of GLRaV-3 by the vine mealybug and showed that transmission of this virus occurs in a semipersistent manner. This research fills in important gaps in knowledge of leafroll virus transmission, which is critical for development of leafroll disease management practices.

The multiple merger assembly of a hyperluminous obscured quasar at redshift 4.6.

Galaxy mergers and gas accretion from the cosmic web drove the growth of galaxies and their central black holes at early epochs. We report spectroscopic imaging of a multiple merger event in the most luminous known galaxy, WISE J224607.56-052634.9 (W2246-0526), a dust-obscured quasar at redshift 4.6, 1.3 billion years after the Big Bang. Far-infrared dust continuum observations show three galaxy companions around W2246-0526 with disturbed morphologies, connected by streams of dust likely produced by the dynamical interaction. The detection of tidal dusty bridges shows that W2246-0526 is accreting its neighbors, suggesting that merger activity may be a dominant mechanism through which the most luminous galaxies simultaneously obscure and feed their central supermassive black holes.

The role of XRCC6/Ku70 in nasopharyngeal carcinoma.

The association between XRCC6/Ku70, an upstream player in the DNA double-strand break repair system, and the risk of nasopharyngeal carcinoma (NPC) was examined. In this case-control study, 176 NPC patients and 352 cancer-free controls were genotyped, and the associations of XRCC6 promoter T-991C (rs5751129), promoter G-57C (rs2267437), promoter G-31A (rs132770), and intron 3 (rs132774) polymorphisms with NPC risk were evaluated. NPC tissue samples were also assessed for their XRCC6 mRNA and protein expression by real-time quantitative reverse transcription PCR and Western blotting, respectively. With regard to the XRCC6 promoter T-991C, the TC and CC genotypes were associated with a significantly increased risk of NPC compared with wild-type TT genotype (adjusted odds ratio 2.02 and 3.42, 95% confidence interval 1.21-3.32 and 1.28-8.94, P=0.0072 and 0.0165, respectively). The mRNA and protein expression levels for NPC tissues revealed significantly lower XRCC6 mRNA and protein expression in the NPC samples with TC/CC genotypes compared to those with the TT genotype (P=0.0210 and 0.0164, respectively). These findings suggest that XRCC6 may play an important role in the carcinogenesis of NPC and could serve as a chemotherapeutic target for personalized medicine and therapy.

D-serine added to clozapine for the treatment of schizophrenia.

OBJECTIVE: D-Serine is a full agonist at the glycine site on the N-methyl-D-aspartate (NMDA) receptor. Previous administration of D-serine to schizophrenic patients taking nonclozapine antipsychotics improved positive, negative, and cognitive symptoms, whereas the partial agonist D-cycloserine improved negative symptoms of patients taking conventional antipsychotics but worsened symptoms in clozapine-treated patients. To study the difference between full and partial agonists at the NMDA receptor glycine site, the clinical effects of adding D-serine to clozapine were assessed. METHOD: In a 6-week double-blind trial, 20 schizophrenic patients received placebo or D-serine (30 mg/kg per day) in addition to clozapine. Clinical efficacy, side effects, and serum levels of D-serine were determined every other week. RESULTS: The patients exhibited no improvement with D-serine, nor did their symptoms worsen, as previously reported with D-cycloserine. CONCLUSIONS: The results suggest either that clozapine may have an agonistic effect on the NMDA system or that clozapine-treated patients do not respond to D-serine.

Primary structure and developmental expression of zebrafish sodium channel Na(v)1.6 during neurogenesis.

A zebrafish sodium channel cDNA encoding a 1949-amino acid polypeptide, Na(v)1.6, was isolated. Two transcripts were detected in zebrafish adult brain but not in cardiac or skeletal muscle. The RNase protection analysis confirmed the neural specificity of zebrafish Na(v)1.6 24 hours postfertilization (hpf) Na(v)1.6 was expressed in the trigeminal ganglion, anterior and posterior lateral line ganglia, rhombomeres, and Rohon-Beard neurons. This preferential localization suggests that Na(v)1.6 plays an important role in tactile sensitivity. The abundance of zebrafish Na(v) 1.6 mRNA in the central and peripheral nervous systems increased markedly between 48 and 72 hpf, during the maturation of the nervous system.

Thrombophilia in patients with hypercholesterolemia.

To investigate a possible interrelationship between hypercholesterolemia and the coagulation and fibrinolytic system, the Cardiovascular Disease Risk Factor Two-Township Study in Taiwan was undertaken as a longitudinal prospective study focusing on the evolution of cardiovascular disease risk factors, with an emphasis on hemostatic factors. Hemostatic parameters measured in this study included prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, factor VIIc, factor VIIIc, antithrombin III, and plasminogen. Subjects of both sexes with hypercholesterolemia (> 6.2 mmol/L) also had significant elevations of diastolic blood pressure, plasma glucose, triglycerides, fibrinogen, and factor VIIc and reduced PT and APTT compared with subjects with lower cholesterol. The hypercholesterolemic women additionally had significant elevations of systolic blood pressure and factor VIIc. Levels of the anticoagulant factors, antithrombin III and plasminogen, were also higher in both hypercholesterolemic men and women. In men, only factor VIIIc had no statistically significant elevation. In women, only PT showed no statistical difference. Established coronary risk factors such as fibrinogen and factor VIIc showed remarkable elevations in patients of both sexes. Using Pearson correlation and multiple regression, the most significant parameter related to cholesterol level was factor VIIc. The present results show that hemostatic abnormalities do exist in patients with hypercholesterolemia, and this thrombophilic phenomenon sheds further light on the study of higher cardiovascular mortality in these subjects.

Vasorelaxing effect in rat thoracic aorta caused by denudatin B, isolated from the Chinese herb, magnolia fargesii.

Denudatin B is an antiplatelet agent isolated from the flower buds of Magnolia fargesii. We studied the effects of denudatin B on the vasoconstriction of rat thoracic aorta induced by high potassium (K+) solution, norepinephrine (NE) and caffeine, and to elucidate its mode of action. The contraction of rat aorta caused by high K+ (60 mM) and cumulative concentrations of CaCl2 (0.03-3 mM) was inhibited concentration dependently by denudatin B with an IC50 of 21.2 micrograms/ml. NE (3 microM)-induced phasic and tonic contractions of rat aorta were inhibited by pretreatment with denudatin B (10-100 micrograms/ml). The relaxing action of denudatin B persisted in denuded aorta, in Ca2(+)-free and EGTA (2 mM)-containing medium. The vasorelaxing effects were not affected by indomethacin (20 microM), hemoglobin (10 microM) or methylene blue (50 microM) and were not accompanied by PGI2 formation. In quin-2/AM-loaded cultured rat vascular smooth muscle cells, denudatin B (100 micrograms/ml) inhibited the increase of intracellular calcium caused by NE (3 microM) in the presence or absence of extracellular calcium. Denudatin B did not affect the caffeine (10 mM)-induced contraction and the increase in intracellular calcium. Denudatin B (100 micrograms/ml) increased the cGMP, but not the cAMP level in intact and denuded aorta. The 45Ca2+ influx induced in rat aorta by high K+ (60 mM) or NE (3 microM) was markedly inhibited by denudatin B in a concentration-dependent manner. These results indicate that denudatin B relaxed vascular smooth muscle by inhibiting the Ca2+ influx through voltage-gated and receptor-operated Ca2+ channels; its effect to increase cGMP may enhance the vasorelaxation.

Increased sympathetic nervous system activity in Chinese hypertensive patients with type II diabetes mellitus.

To evaluate the coexistence of sympathetic overactivity and hypertension in type 2 diabetic patients, a population-based study was conducted of newly-diagnosed type 2 diabetic patients recruited from a single community located at northern Taiwan. This study included 2877 (male 1382, female 1495) middle-aged ethnic Chinese adults, aged 45-65 years. Of the 1382 males, 67 had newly-diagnosed type 2 diabetes mellitus, whereas 75 of the 1495 females had type 2 diabetes. The data showed that about 39% of diabetic patients had borderline hypertension (mean blood pressure 141/91 mmHg) whereas the average incidence in non-diabetic subjects was 15.5%. The borderline hypertensive diabetic patients had significantly higher heart rates (mean 78.8 vs. 69.3 beats/min; P < 0.001) than control subjects. However, the cardiac index was similar in both control and diabetic subjects (mean 2.48 vs. 2.53 l/min/m2; P > 0.05). Our data show that sympathetic overactivity and increased incidence of hypertension actually existed in these type 2 diabetic patients of Chinese origin.

Salmonellosis and mycotic aneurysm of the aorta. A report of 10 cases.

We report a 5 year experience of 10 cases of mycotic aneurysms of the aorta caused by salmonella infection. Of the 10 patients, nine were males and one was female in an age range from 60 to 80 years with a mean of 71 years. The major clinical manifestations were fever, abdominal or back pain, pulsatile abdominal mass and leucocytosis. The diagnosis was based on clinical symptoms and signs and positive blood or tissue cultures. The main confirmatory procedure was computed tomography (CT). Two year survival rate was 20%. Five patients died during hospitalisation, without surgery. Three patients died within 2 months of surgery. The other two patients, treated surgically and by intensive antibiotic therapy, survived. Death resulted usually from recurrent infection and graft leakage. Contrary to previous reports, salmonella mycotic aneurysm is still common in this geographical area and the prognosis is poor.

Analysis of specific adaptation to a domicile habitat: a comparative study of two closely related cockroach species.

The German cockroach, Blattella germanica (L.), and the closely related species B. bisignata (Brunner) belong to the germanica species group. They are similar in appearance, life history, reproductive cycle, and courtship behavior. The most significant difference is habitat preferences: B. germanica is a household species and lives in crowded conditions, whereas the feral B. bisignata lives outdoors in a solitary manner. Nevertheless, B. bisignata has recently been found in households. A comparison between the two species has shown that B. germanica displays gregarious behavior and produces an aggregation pheromone, whereas both characters are absent in B. bisignata. Mate preference experiments have revealed that B. germanica females accepted only conspecific males, whereas B. bisignata females mated with males from both species, provided that long distance calling was bypassed. In addition, the high reproductive potential of B. germanica outcompeted the other species: when 10 pairs of B. germanica and of B. bisignata were kept together in crowded conditions during 3 mo, B. bisignata was driven into extinction. It is concluded that the chances of B. bisignata becoming a new household species are remote.

Microskin grafting of rabbit skin wounds with Biobrane overlay.

Biobrane was used to overlay micrografts and the wound using the microskin grafting technique with an expansion ratio of 10:1 in 16 rabbits. The rabbits were divided randomly into four groups, with four rabbits in each group, for evaluating the wound conditions on days 7, 10, 12 and 14. Histological examination of the removed Biobrane showed a variable degree of entrapment of inflammatory cells within the nylon fabric. Biobrane adhered well to the wounds although many wrinkles containing fluid accumulations were noted on day 7. By 10, 12 and 14 days all the wounds become dry and their Biobrane adhered completely. Histological examination of the grafted wound on day 7 showed active proliferation and spread of micrografts. In the later groups, the neoepidermis increased in thickness and differentiated into skin with a normal texture. On day 10, the wounds were almost completely resurfaced with neoepithelium. The growth of these grafts progressed smoothly as the adherent Biobrane was kept on the wound for 12 or 14 days. In these animal studies, the overlain Biobrane provided favourable conditions for the successful growth of micrografts.

An easy way to prepare microskin grafts.

The conventional technique to produce microskin grafts is a relatively time-consuming procedure. We developed an easy method by using a trimmed circular dermacarrier with the non-grooved side up and driving forward in the meshgraft instrument through six different angles that were 30 degrees apart. The tiny skin particles obtained by this method not only saved operation time but also survived well in the grafted wounds.

Clinical application of adipofascial turn-over flaps for burn wounds.

Local adipofascial turn-over flaps overlaid with skin grafts were used successfully to reconstruct nine deep burn wounds following electric injuries or contact burns in seven patients. Durable flap coverage of the exposed tendons, joints or bones can be achieved with a one-stage procedure. Appropriate length-to-width ratio and flap-to-base area ratio, and the tension-free insetting of the flap are essential for flap survival. The non-adherent characteristic of the adiposal component of the flap enables the underlying involved tendons or joints to glide through without adherence, and the rich vascular network in the fascia provides an ideal bed for the skin graft. The adipofascial turn-over flap is a reliable and simple technique for reconstruction of certain deep burn wounds if the surrounding soft tissue is available. The functional and cosmetic results in our series have been rewarding and satisfactory.

Running Y-V-plasty for burn scar contracture.

Seventeen patients with 24 regions received running Y-V-plasties to release burn scar contractures over a 3-year period. The scar band can be completely interrupted and lengthened without the need for undermining and transposition of the skin flaps, circulatory embarrassment of the flaps can be avoided. The wound morbidity was extremely low, and no recurrence of the contracture was noted during follow-up periods. The running Y-V-plasty has unique advantages for the treatment of cord-like or linear burn scar contractures. This approach resulted in shorter hospital stay and allows early mobilization of the involved extremities.

Microskin autograft with pigskin xenograft overlay: a preliminary report of studies on patients.

Split-thickness pigskin graft (STPSG) was used to replace allograft skin for microskin grafting in 16 patients, nine of whom were burn patients, five suffered from traumatic defects and two from diabetic ulcers. The expansion ratios used in these patients ranged from 8:1 to 12:1. The STPSG preparation described was found to be safe for clinical application. The autogenous donor skin was excised from the inguinal area, and the donor site was primarily closed. There were no instances of donor site morbidity. The majority of the STPSG overlays adhered to the wound firmly. Histological examination showed that the microskin grafts proliferated actively immediately beneath the STPSG overlay. The time for the wound to be fully resurfaced varied from 13 to 21 days depending on the expansion ratio employed. There were only two episodes of pseudomonas infection and no further grafting was required in any of the patients. In this study the pigskin xenograft was found to provide a suitable environment for the epithelialization of microskin autografts. When allograft is not available, this is an alternative way of ensuring successful microskin grafting.