Effects of bound nucleotides on the secondary structure, thermal stability, and phosphorylation of Rab3A

Rab3A is a member of the Rab GTPase family involved in synaptic vesicle trafficking. Recent evidence has demonstrated that Rab3A is phosphorylated by leucine-rich repeat kinase 2 (LRRK2) that is implicated in both familial and sporadic forms of Parkinson's disease (PD), and an abnormal increase in Rab3A phosphorylation has been proposed as a cause of PD. Despite the potential importance of Rab3A in PD pathogenesis, its structural information is limited and the effects of bound nucleotides on its biophysical and biochemical properties remain unclear. Here, we show that GDP-bound Rab3A is preferentially phosphorylated by LRRK2 compared with GTP-bound Rab3A. The secondary structure of Rab3A, measured by circular dichroism (CD) spectroscopy, revealed that Rab3A is resistant to heat-induced denaturation at pH 7.4 or 9.0 regardless of the nucleotides bound. In contrast, Rab3A underwent heat-induced denaturation at pH 5.0 at a lower temperature in its GDP-bound form than in its GTP-bound form. The unfolding temperature of Rab3A was studied by differential scanning fluorimetry, which showed a significantly higher unfolding temperature in GTP-bound Rab3A than in GDP-bound Rab3A, with the highest at pH 7.4. These results suggest that Rab3A has unusual thermal stability under physiologically relevant conditions and that bound nucleotides influence both thermal stability and phosphorylation by LRRK2.

Predictive Model for Extended-Spectrum β-Lactamase-Producing Bacterial Infections Using Natural Language Processing Technique and Open Data in Intensive Care Unit Environment: Retrospective Observational Study

BACKGROUND

Machine learning has advanced medical event prediction, mostly using private data. The public MIMIC-3 (Medical Information Mart for Intensive Care III) data set, which contains detailed data on over 40,000 intensive care unit patients, stands out as it can help develop better models including structured and textual data.

OBJECTIVE

This study aimed to build and test a machine learning model using the MIMIC-3 data set to determine the effectiveness of information extracted from electronic medical record text using a named entity recognition, specifically QuickUMLS, for predicting important medical events. Using the prediction of extended-spectrum β-lactamase (ESBL)-producing bacterial infections as an example, this study shows how open data sources and simple technology can be useful for making clinically meaningful predictions.

METHODS

The MIMIC-3 data set, including demographics, vital signs, laboratory results, and textual data, such as discharge summaries, was used. This study specifically targeted patients diagnosed with Klebsiella pneumoniae or Escherichia coli infection. Predictions were based on ESBL-producing bacterial standards and the minimum inhibitory concentration criteria. Both the structured data and extracted patient histories were used as predictors. In total, 2 models, an L1-regularized logistic regression model and a LightGBM model, were evaluated using the receiver operating characteristic area under the curve (ROC-AUC) and the precision-recall curve area under the curve (PR-AUC).

RESULTS

Of 46,520 MIMIC-3 patients, 4046 were identified with bacterial cultures, indicating the presence of K pneumoniae or E coli. After excluding patients who lacked discharge summary text, 3614 patients remained. The L1-penalized model, with variables from only the structured data, displayed a ROC-AUC of 0.646 and a PR-AUC of 0.307. The LightGBM model, combining structured and textual data, achieved a ROC-AUC of 0.707 and a PR-AUC of 0.369. Key contributors to the LightGBM model included patient age, duration since hospital admission, and specific medical history such as diabetes. The structured data-based model showed improved performance compared to the reference models. Performance was further improved when textual medical history was included. Compared to other models predicting drug-resistant bacteria, the results of this study ranked in the middle. Some misidentifications, potentially due to the limitations of QuickUMLS, may have affected the accuracy of the model.

CONCLUSIONS

This study successfully developed a predictive model for ESBL-producing bacterial infections using the MIMIC-3 data set, yielding results consistent with existing literature. This model stands out for its transparency and reliance on open data and open-named entity recognition technology. The performance of the model was enhanced using textual information. With advancements in natural language processing tools such as BERT and GPT, the extraction of medical data from text holds substantial potential for future model optimization.

Detection of feline morbillivirus in cats with symptoms of acute febrile infection

Feline morbillivirus (FeMV) was identified for the first time in cats in 2012 in Hong Kong. Although its association with chronic kidney disease in cats has attracted the attention of researchers, its clinical significance as an acute infection has not been reported. Previously, we reported FeMV detection using next-generation sequence-based comprehensive genomic analysis of plasma samples from cats with suspected acute febrile infections. Here, we conducted an epidemiological survey to detect FeMV by quantitative reverse transcription polymerase chain reaction (qRT-PCR) using blood samples from cats in Japan. FeMV was detected in 32/102 blood samples (31.4%) from cats with suspected acute viral infections. Most of the FeMV-positive cats had clinical findings consistent with acute viral infections, including fever, leukopenia, thrombocytopenia and jaundice. No FeMV was detected in healthy cats or clinically ill cats that visited veterinary hospitals. Phylogenetic analysis classified FeMV L genes into various FeMV subtypes. We also necropsied a FeMV-positive cat that died of a suspected acute infection. On necropsy, FeMV was detected in systemic organs, including the kidneys, lymph nodes and spleen by qRT-PCR and immunohistochemical staining. These results suggest that FeMV infections may cause acute symptomatic febrile infections in cats. A limitation of this study was that the involvement of other pathogens that cause febrile illnesses could not be ruled out and this prevented a definitive conclusion that FeMV causes febrile disease in infected cats. Further studies that include experimental infections are warranted to determine the pathogenicity of FeMV in cats.

Wastewater-based reproduction numbers and projections of COVID-19 cases in three areas in Japan, November 2021 to December 2022

BackgroundWastewater surveillance has expanded globally as a means to monitor spread of infectious diseases. An inherent challenge is substantial noise and bias in wastewater data because of the sampling and quantification process, limiting the applicability of wastewater surveillance as a monitoring tool.AimTo present an analytical framework for capturing the growth trend of circulating infections from wastewater data and conducting scenario analyses to guide policy decisions.MethodsWe developed a mathematical model for translating the observed SARS-CoV-2 viral load in wastewater into effective reproduction numbers. We used an extended Kalman filter to infer underlying transmissions by smoothing out observational noise. We also illustrated the impact of different countermeasures such as expanded vaccinations and non-pharmaceutical interventions on the projected number of cases using three study areas in Japan during 2021-22 as an example.ResultsObserved notified cases were matched with the range of cases estimated by our approach with wastewater data only, across different study areas and virus quantification methods, especially when the disease prevalence was high. Estimated reproduction numbers derived from wastewater data were consistent with notification-based reproduction numbers. Our projections showed that a 10-20% increase in vaccination coverage or a 10% reduction in contact rate may suffice to initiate a declining trend in study areas.ConclusionOur study demonstrates how wastewater data can be used to track reproduction numbers and perform scenario modelling to inform policy decisions. The proposed framework complements conventional clinical surveillance, especially when reliable and timely epidemiological data are not available.

Impact of meteorological and demographic factors on the influenza epidemic in Japan: a large observational database study

Factors affecting the start date of the influenza epidemic season and total number of infected persons per 1,000,000 population in 47 prefectures of Japan were evaluated. This retrospective observational study (September 2014-August 2019; N = 472,740-883,804) evaluated data from a Japanese health insurance claims database. Single and multiple regression analyses evaluated the time to start of the epidemic or total infected persons per 1,000,000 population with time to absolute humidity (AH) or number of days with AH (≤ 5.5, ≤ 6.0, ≤ 6.5, and ≤ 7.0), total visitors (first epidemic month or per day), and total population. For the 2014/15, 2015/16, and 2016/17 seasons, a weak-to-moderate positive correlation (R2: 0.042-0.417) was observed between time to start of the epidemic and time to first day with AH below the cutoff values. Except in the 2016/17 season (R2: 0.089), a moderate correlation was reported between time to start of the epidemic and the total population (R2: 0.212-0.401). For all seasons, multiple regression analysis showed negative R2 for time to start of the epidemic and total visitors and population density (positive for time to AH ≤ 7.0). The earlier the climate becomes suitable for virus transmission and the higher the human mobility (more visitors and higher population density), the earlier the epidemic season tends to begin.

Overview of the Impact of Pathogenic LRRK2 Mutations in Parkinson's Disease

Leucine-rich repeat kinase 2 (LRRK2) is a large protein kinase that physiologically phosphorylates and regulates the function of several Rab proteins. LRRK2 is genetically implicated in the pathogenesis of both familial and sporadic Parkinson's disease (PD), although the underlying mechanism is not well understood. Several pathogenic mutations in the LRRK2 gene have been identified, and in most cases the clinical symptoms that PD patients with LRRK2 mutations develop are indistinguishable from those of typical PD. However, it has been shown that the pathological manifestations in the brains of PD patients with LRRK2 mutations are remarkably variable when compared to sporadic PD, ranging from typical PD pathology with Lewy bodies to nigral degeneration with deposition of other amyloidogenic proteins. The pathogenic mutations in LRRK2 are also known to affect the functions and structure of LRRK2, the differences in which may be partly attributable to the variations observed in patient pathology. In this review, in order to help researchers unfamiliar with the field to understand the mechanism of pathogenesis of LRRK2-associated PD, we summarize the clinical and pathological manifestations caused by pathogenic mutations in LRRK2, their impact on the molecular function and structure of LRRK2, and their historical background.

LRRK2-mediated phosphorylation and thermal stability of Rab12 are regulated by bound nucleotides

An abnormal increase in the phosphorylation of Rab12 by leucine-rich repeat kinase 2 (LRRK2), a serine/threonine kinase genetically linked to Parkinson's disease (PD), has been implicated in the pathogenesis of PD, although the underlying mechanism remains unclear. In this report, we show that LRRK2 phosphorylates Rab12 more efficiently in its GDP-bound form than in its GTP-bound form using an in vitro phosphorylation assay. This observation suggests that LRRK2 recognizes the structural difference of Rab12 caused by the bound nucleotide and that Rab12 phosphorylation inhibits its activation. Circular dichroism data revealed that Rab12, in its GDP-bound form, is more susceptible to heat-induced denaturation than its GTP-bound form, which was exacerbated at basic pH. Differential scanning fluorimetry showed that heat-induced denaturation of Rab12 in its GDP-bound form occurs at a lower temperature than in its GTP-bound form. These results suggest that the type of nucleotide bound to Rab12 determines the efficiency of LRRK2-mediated phosphorylation and the thermal stability of Rab12, and provide insights into elucidating the mechanism of the abnormal increase in Rab12 phosphorylation.

Detection of domestic cat hepadnavirus by next-generation sequencing and epidemiological survey in Japan

The novel domestic cat hepadnavirus (DCH), a member of the Hepadnaviridae, was first detected in Australia and has recently been identified in more countries. In this study, we explored the DCH genome using next-generation sequencing of a plasma sample from a cat with a fever of unknown cause. Nucleotide sequence analysis showed the virus to be relatively genetically distant from the first reported DCH in Australia, showing 89% homology. Then we conducted an epidemiological survey by PCR of plasma samples collected from 203 cats that visited a veterinary hospital for diagnosis and treatment. Two of the 203 surveyed cats a were positive for DCH. One of the two positive cases had elevated liver enzymes of unknown etiology, and the other had hepatoma. Our study indicated that DCH infection was observed in domestic cats in the Tokyo area of Japan as well as other reported areas in the world. Further investigations are needed to define the clinical importance of DCH.

Pathogenic LRRK2 compromises the subcellular distribution of lysosomes in a Rab12-RILPL1-dependent manner

Mutations in leucine-rich repeat kinase 2 (LRRK2) cause familial Parkinson's disease (PD). Recent studies have shown that LRRK2 physiologically phosphorylates several Rab family proteins including Rab12 and that this phosphorylation is accelerated by the pathogenic mutations in LRRK2, although the significance in the PD pathogenesis remains unknown. Here we examined the effect of the overexpression of LRRK2 on the distribution of organelles in cultured cells and found that lysosomes become clustered in a perinuclear region upon the overexpression of pathogenic mutant LRRK2 in a manner dependent on its kinase activity. The perinuclear clustering of lysosomes was abolished by knocking out RAB12 as well as its effector protein RILPL1. Re-expression of Rab12 in RAB12 knockout cells suggested that the phosphorylation at Ser106 of Rab12 is required for the perinuclear clustering of lysosomes. Moreover, phosphorylated Rab12 was also accumulated on the clustered lysosomes, and the phosphorylation of Rab12 increased its interaction with RILPL1, leading us to conclude that the increase in the phosphorylation of Rab12 by pathogenic LRRK2 compromised intracellular lysosomal transport via the enhanced interaction of Rab12 with RILPL1. These data suggest the involvement of abnormal regulation of lysosomal transport in the LRRK2-mediated pathogenesis of PD.

Site-specific amino acid D-isomerization of Tau R2 and R3 peptides changes the fibril morphology, resulting in attenuation of Tau aggregation inhibitor potency

Tau, a microtubule-binding protein, is a major component of neurofibrillary tangles in the brains of Alzheimer's disease patients. Tau aggregation following fibril formation induces Alzheimer's disease pathogenesis. The accumulation of D-isomerized amino acids in proteins that occurs in several tissues with aging is thought to be implicated in age-related diseases. D-isomerized Asp accumulation has also been found in Tau in neurofibrillary tangles. We previously demonstrated the effects of D-isomerization of Asp within microtubule-binding repeat peptides of Tau, Tau R2, and R3 on the rates of structural transition and fibril formation. Here, we investigated the potency of Tau aggregation inhibitors on fibril formation of wild-type Tau R2 and R3 peptides and D-isomerized Asp-containing Tau R2 and R3 peptides. D-isomerization of Asp within Tau R2 and R3 peptides attenuated the potency of inhibitors. We next investigated the fibril morphology of D-isomerized Asp-containing Tau R2 and R3 peptides by electron microscopy. D-isomerized Asp-containing Tau R2 and R3 fibrils showed significantly different fibril morphology from that of wild-type peptides. Our results indicate that D-isomerization of Asp within Tau R2 and R3 peptides affects fibril morphology, resulting in attenuation of the potency of Tau aggregation inhibitors.

INPP5D modulates TREM2 loss-of-function phenotypes in a β-amyloidosis mouse model

The genetic associations of TREM2 loss-of-function variants with Alzheimer disease (AD) indicate the protective roles of microglia in AD pathogenesis. Functional deficiencies of TREM2 disrupt microglial clustering around amyloid β (Aβ) plaques, impair their transcriptional response to Aβ, and worsen neuritic dystrophy. However, the molecular mechanism underlying these phenotypes remains unclear. In this study, we investigated the pathological role of another AD risk gene, INPP5D, encoding a phosphoinositide PI(3,4,5)P3 phosphatase expressed in microglia. In a Tyrobp-deficient TREM2 loss-of-function mouse model, Inpp5d haplodeficiency restored the association of microglia with Aβ plaques, partially restored plaque compaction, and astrogliosis, and reduced phosphorylated tau+ dystrophic neurites. Mechanistic analyses suggest that TREM2/TYROBP and INPP5D exert opposing effects on PI(3,4,5)P3 signaling pathways as well as on phosphoproteins involved in the actin assembly. Our results suggest that INPP5D acts downstream of TREM2/TYROBP to regulate the microglial barrier against Aβ toxicity, thereby modulates Aβ-dependent pathological conversion of tau.

The atypical Rab GTPase associated with Parkinson's disease, Rab29, is localized to membranes

Several genetic studies have shown that the small GTPase Rab29 is involved in the pathogenesis of Parkinson's disease (PD). It has also been shown that overexpression of Rab29 increases the activity of leucine-rich repeat kinase 2 (LRRK2), a protein kinase often mutated in familial PD, although the mechanism underlying this activation remains unclear. Here we employed biochemical analyses to characterize the localization of Rab29 and found that unlike general Rab proteins, Rab29 is predominantly fractionated into the membrane fraction by ultracentrifugation. We also found that Rab29 is resistant to extraction from membranes by GDP-dissociation inhibitors (GDIs) in vitro. Furthermore, Rab29 failed to interact with GDIs, and its membrane localization was not affected by the knockout of GDIs in cells. We show that knockout of Rab geranylgeranyltransferase decreased the hydrophobicity of Rab29, suggesting that Rab29 is geranylgeranylated at its carboxyl terminus as is with typical Rab proteins. Notably, we demonstrated that membrane-bound Rab29 retains some hydrophilicity, indicating that mechanisms other than geranylgeranylation might also be involved in the membrane localization of Rab29. Taken together, these findings uncover the atypical nature of Rab29 among Rab proteins, which will provide important clues for understanding how Rab29 is involved in the molecular pathomechanism of PD.

Seroprevalence of antibodies against severe acute respiratory coronavirus 2 (SARS-CoV-2) in household dogs in Japan

We investigated the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among dogs in the Tokyo area via enzyme-linked immunosorbent assay (ELISA) using the spike protein as the target antigen. Plasma samples from 494 household dogs and blood-donor dogs were tested from July 2020 to January 2021. Of these samples, three showed optical densities that were higher than the mean plus two standard deviations of the mean of the negative-control optical densities (ODs). Of these three samples, only the sample with the highest OD by ELISA was confirmed positive by virus neutralization testing. The positive dog presented no SARS-CoV-2-related symptoms. The positivity rate of SARS-CoV-2 infections among dogs in the Tokyo area was approximately 0.2%.

The Regulation of Rab GTPases by Phosphorylation

Rab proteins are small GTPases that act as molecular switches for intracellular vesicle trafficking. Although their function is mainly regulated by regulatory proteins such as GTPase-activating proteins and guanine nucleotide exchange factors, recent studies have shown that some Rab proteins are physiologically phosphorylated in the switch II region by Rab kinases. As the switch II region of Rab proteins undergoes a conformational change depending on the bound nucleotide, it plays an essential role in their function as a ‘switch’. Initially, the phosphorylation of Rab proteins in the switch II region was shown to inhibit the association with regulatory proteins. However, recent studies suggest that it also regulates the binding of Rab proteins to effector proteins, determining which pathways to regulate. These findings suggest that the regulation of the Rab function may be more dynamically regulated by phosphorylation than just through the association with regulatory proteins. In this review, we summarize the recent findings and discuss the physiological and pathological roles of Rab phosphorylation.

BORCS6 is involved in the enlargement of lung lamellar bodies in Lrrk2 knockout mice

Leucine-rich repeat kinase 2 (LRRK2) has been implicated in the pathogenesis of Parkinson disease. It has been shown that Lrrk2 knockout (KO) rodents have enlarged lamellar bodies (LBs) in their alveolar epithelial type II cells, although the underlying mechanisms remain unclear. Here we performed proteomic analyses on LBs isolated from Lrrk2 KO mice and found that the LB proteome is substantially different in Lrrk2 KO mice compared with wild-type mice. In Lrrk2 KO LBs, several Rab proteins were increased, and subunit proteins of BLOC-1-related complex (BORC) were decreased. The amount of surfactant protein C was significantly decreased in the bronchoalveolar lavage fluid obtained from Lrrk2 KO mice, suggesting that LB exocytosis is impaired in Lrrk2 KO mice. We also found that the enlargement of LBs is recapitulated in A549 cells upon KO of LRRK2 or by treating cells with LRRK2 inhibitors. Using this model, we show that KO of BORCS6, a BORC subunit gene, but not other BORC genes, causes LB enlargement. Our findings implicate the LRRK2-BORCS6 pathway in the maintenance of LB morphology.

Risk factors for severe neutropenia in pancreatic cancer patients treated with gemcitabine/nab-paclitaxel combination therapy

AIM

Combination therapy with gemcitabine and nanoparticle albumin-bound paclitaxel (nab-paclitaxel), known as GnP therapy, significantly prolongs the survival of pancreatic cancer patients compared with gemcitabine monotherapy. However, it may cause severe neutropenia, requiring discontinuation of treatment. This study aimed to clarify the risk factors for Grade 3/4 neutropenia during GnP therapy.

METHODS

Clinical data of pancreatic cancer patients who underwent GnP therapy at the Cancer Institute Hospital of the Japanese Foundation for Cancer Research from December 2014 to December 2016 were retrospectively collected. The relationship of Grade 3/4 neutropenia onset to laboratory values and patient background factors was investigated by multivariate logistic regression analysis.

RESULTS

Clinical data of 222 patients were analyzed. Grade 3/4 neutropenia occurred in 118 patients (53.2%) in the first cycle of GnP therapy. Multivariate analysis identified low absolute neutrophil count (ANC), high total bilirubin (T-Bil), and low C-reactive protein (CRP) as risk factors for Grade 3/4 neutropenia. Age was not a risk factor. The incidence of neutropenia was 85.7% in patients with all three risk factors, but only 27.7% in patients with none of them.

CONCLUSION

Low ANC, high T-Bil, and low CRP may be risk factors for Grade 3/4 neutropenia in patients receiving GnP therapy, even if these laboratory values are within normal reference ranges. Patients with these risk factors should be carefully monitored for adverse events.

Detection of Substrate Phosphorylation of LRRK2 in Tissues and Cultured Cells

Recent studies revealed that leucine-rich repeat kinase 2 (LRRK2) phosphorylates several Rab proteins under physiological conditions. Mutations linked with familial Parkinson's disease cause an abnormal increase in the Rab phosphorylation, which has not been elucidated in an in vitro kinase assays where artificial peptide substrates are often used. Here, we provide protocols for detecting the LRRK2 activity in tissues and cultured cells using Rab phosphorylation as a readout.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Risk factors for severe neutropenia among pancreatic cancer patients receiving nab-paclitaxel and gemcitabine combination therapy

684

Background: Albumin-bound paclitaxel (nab-paclitaxel) and gemcitabine combination therapy (GnP therapy) significantly extends overall survival in patients with metastatic pancreatic cancer, compared to conventional gemcitabine monotherapy. However, severe neutropenia (Grade ≥ 3) occurred in 67.6% of patients in the Japanese phase I/II trials of GnP therapy, and is often a limiting factor. The purpose of this study was to identify the risk factors for severe neutropenia in pancreatic patients receiving GnP therapy in clinical settings. Methods: A retrospective study of 222 consecutive patients with pancreatic cancer who received GnP therapy at the Cancer Institute Hospital from December 2014 to December 2016 was conducted. Univariate and multivariate analyses were used to compare blood test values and patients’ characteristics between patients with no neutropenia or Grade 1/2 (non-serious) neutropenia and those with Grade ≥ 3 (severe) neutropenia. Results: There were 19 patients (8.6%) with modified FOLFIRINOX in the previous treatment history. The median doses of nab-paclitaxel and gemcitabine were 192.5 mg (range 134-277.5) and 1,545 mg (range 1,000-2,220), respectively. Severe neutropenia and febrile neutropenia occurred in 118 patients (53.2%) and 15 patients (6.8%), respectively. Multivariate logistic regression analysis indicated that ANC (absolute neutrophil count) < 3.03 x 103 /μL (OR: 4.806, 95% CI: 2.416-9.558, p = 0.000), T-Bil ≥ 0.6 mg/dl (OR: 1.964, 95% CI: 1.040-3.708, p = 0.037) and CRP < 0.13 mg/dl (OR: 2.607, 95% CI: 1.331-5.106, p = 0.005) were significant risk factors for severe neutropenia. The incidence rate of severe neutropenia was 85.7% (18/21) in patients with all three identified factors, while it was 27.7% (13/47) in patients with none of them. Age was not a risk factor in either univariate or multivariate analysis. Conclusions: Low ANC, high T-Bil, and low CRP were found to be risk factors for severe neutropenia in patients receiving GnP therapy. It would be desirable to monitor patients with these risk factors carefully, even if their values are within the standard ranges.

Selective amplitude-level regeneration based on blue-chirp spectral slicing using QD-SOAs

We present a novel optical amplitude regenerator based on blue-chirp spectral slicing using a semiconductor optical amplifier (SOA). The combination of blue-chirp spectral slicing and gain competition in the SOA has a unique input/output (I/O) power-transfer function, which is controlled by the power of an input data signal injected into the SOA. The I/O power-transfer function provides selective amplitude-level regeneration of either the mark or space level of the input data signal. In this paper, we experimentally investigate the transfer function and the regeneration effect using a quantum-dot semiconductor optical amplifier. The results show that the regenerator has unique regeneration effect, specialized for either the mark or space level of a 10-Gbit/s on-off keying signal.

Physiological and pathological functions of LRRK2: implications from substrate proteins

Leucine-rich repeat kinase 2 (LRRK2) encodes a 2527-amino acid (aa) protein composed of multiple functional domains, including a Ras of complex proteins (ROC)-type GTP-binding domain, a carboxyl terminal of ROC (COR) domain, a serine/threonine protein kinase domain, and several repeat domains. LRRK2 is genetically involved in the pathogenesis of both sporadic and familial Parkinson's disease (FPD). Parkinson's disease (PD) is the second most common neurodegenerative disorder, manifesting progressive motor dysfunction. PD is pathologically characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta, and the presence of intracellular inclusion bodies called Lewy bodies (LB) in the remaining neurons. As the most frequent PD-causing mutation in LRRK2, G2019S, increases the kinase activity of LRRK2, an abnormal increase in LRRK2 kinase activity is believed to contribute to PD pathology; however, the precise biological functions of LRRK2 involved in PD pathogenesis remain unknown. Although biochemical studies have discovered several substrate proteins of LRRK2 including Rab GTPases and tau, little is known about whether excess phosphorylation of these substrates is the cause of the neurodegeneration in PD. In this review, we summarize latest findings regarding the physiological and pathological functions of LRRK2, and discuss the possible molecular mechanisms of neurodegeneration caused by LRRK2 and its substrates.

Human Health Risk from Consumption of Marine Fish Contaminated with DDT and Its Metabolites in Maputo Bay, Mozambique

Many countries with incidence of malaria, including those surrounding Maputo Bay, use dichloro-diphenyl-trichloroethane (DDT) to reduce mosquitoes. This study is the first to estimate the human health risk associated with consumption of marine fish from Maputo Bay contaminated with DDTs. The median for ∑DDTs was 3.8 ng/g ww (maximum 280.9 ng/g ww). The overall hazard ratio for samples was 1.5 at the 75th percentile concentration and 28.2 at the 95th percentile. These calculations show increased potential cancer risks due to contamination by DDTs, data which will help policy makers perform a risk-benefit analysis of DDT use in malaria control programs in the region.

Rab10 Phosphorylation Detection by LRRK2 Activity Using SDS-PAGE with a Phosphate-binding Tag

Mutations in leucine-rich repeat kinase 2 (LRRK2) have been shown to be linked with familial Parkinson's disease (FPD). Since abnormal activation of the kinase activity of LRRK2 has been implicated in the pathogenesis of PD, it is essential to establish a method to evaluate the physiological levels of the kinase activity of LRRK2. Recent studies revealed that LRRK2 phosphorylates members of the Rab GTPase family, including Rab10, under physiological conditions. Although the phosphorylation of endogenous Rab10 by LRRK2 in cultured cells could be detected by mass spectrometry, it has been difficult to detect it by immunoblotting due to the poor sensitivity of currently available phosphorylation-specific antibodies for Rab10. Here, we describe a simple method of detecting the endogenous levels of Rab10 phosphorylation by LRRK2 based on immunoblotting utilizing sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) combined with a phosphate-binding tag (P-tag), which is N-(5-(2-aminoethylcarbamoyl)pyridin-2-ylmetyl)-N,N',N'-tris(pyridin-2-yl-methyl)-1,3-diaminopropan-2-ol. The present protocol not only provides an example of the methodology utilizing the P-tag but also enables the assessment of how mutations as well as inhibitor treatment/administration or any other factors alter the downstream signaling of LRRK2 in cells and tissues.

Analysis of DNA methylation of potential age-related methylation sites in canine peripheral blood leukocytes

Reliable methodology for predicting the age of mature dogs is currently unavailable. In this study, amplicon sequencing of 50 blood samples obtained from diseased dogs was used to measure methylation in seven DNA regions. Significant correlations between methylation level and age were identified in four of the seven regions. These four regions were then tested in samples from 31 healthy toy poodles, and correlations were detected in two regions. The age of another 11 dogs was predicted using data from the diseased dogs and the healthy poodles. The mean difference between the actual and calculated ages was 34.3 and 23.1 months, respectively. Further research is needed to identify additional sites of age-related methylation and allow accurate age prediction in dogs.