NanoBRET™ Live-Cell Kinase Selectivity Profiling Adapted for High-Throughput Screening

Kinases represent one of the most therapeutically tractable targets for drug discovery in the twenty-first century. However, confirming engagement and achieving intracellular kinase selectivity for small-molecule kinase inhibitors can represent noteworthy challenges. The NanoBRETTM platform enables broad-spectrum live-cell kinase selectivity profiling in most laboratory settings, without advanced instrumentation or expertise. However, the prototype workflow for this selectivity profiling is currently limited to manual liquid handling and 96-well plates. Herein, we describe a scalable workflow with automation and acoustic dispensing, thus dramatically improving the throughput. Such adaptations enable profiling of larger compound sets against 192 full-length protein kinases in live cells, with statistical robustness supporting quantitative analysis.

Association of Albuminuria and Regression of Chronic Kidney Disease in Adults With Newly Diagnosed Moderate to Severe Chronic Kidney Disease

IMPORTANCE

People with chronic kidney disease (CKD) are risk-stratified for adverse events based on estimated glomerular filtration rate (eGFR) and albuminuria level. CKD has often a favorable course (CKD regression) regardless of eGFR. Determining whether lower albuminuria is associated with CKD regression may have implications on CKD management.

OBJECTIVE

To assess the 5-year probability of CKD regression across albuminuria categories accounting for the competing risks of CKD progression and death in people with newly diagnosed CKD and the association between albuminuria level and CKD regression.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study used administrative and laboratory data from Alberta, Canada, for adults with incident moderate to severe CKD (defined as sustained eGFR of 15-44 mL/min/1.73 m2 for >90 days), between April 1, 2008, and March 31, 2017, and albuminuria measures before cohort entry. Data analysis occurred in January to June 2022.

EXPOSURE

Albuminuria categories were defined by albumin to creatinine ratios (ACRs): A1 (ACR, <3 mg/mmol), A2 (ACR, 3-29 mg/mmol), A3<60 (ACR, 30-59 mg/mmol), and A3≥60 (ACR, ≥60 mg/mmol).

MAIN OUTCOMES AND MEASURES

The main outcome was time to the earliest of CKD regression or progression (sustained change in CKD stage for >3 months and ≥25% increase or decrease in eGFR from baseline or kidney failure, respectively), death, or censoring (outmigration or study end date: March 31, 2019). Cumulative incidence functions were used to estimate absolute risks, and cause-specific Cox models were used to assess the association between albuminuria and CKD regression, accounting for age, sex, eGFR, comorbidities, and health services use indicators.

RESULTS

Of 58 004 people with moderate to severe CKD (mean [SD] age, 77 [12] years; 31 725 [55%] women), 35 360 had A1 albuminuria (61%), 15 597 had A2 albuminuria (27%), 1527 had A3<60 albuminuria (3%), and 5520 had A3≥60 albuminuria (10%). Five-year probability of regression was highest with A1 (22.6%), followed by A2 (16.5%), and A3<60 (11.6%) and lowest with A3≥60 (5.3%). Using A1 albuminuria as the reference group, the hazard of regression was highest for A2 (hazard ratio [HR], 0.75; 95% CI, 0.72-0.79), then A3<60 (HR, 0.47; 95% CI, 0.40-0.54), and lowest for A3≥60 (HR, 0.27; 95% CI, 0.24-0.30).

CONCLUSIONS AND RELEVANCE

In this cohort study of people with moderate to severe CKD, albuminuria levels were inversely associated with CKD regression. These findings extend the key prognostic role of albuminuria, offering novel opportunities to discuss both favorable and adverse outcomes in people with CKD and inform CKD management.

Complementary target engagement and functional assays to probe NLRP3 inflammasome pathway antagonism

Inflammasomes are critical to the innate immune system and implicated in numerous chronic and acute inflammatory diseases. Having tools to screen inflammasome modulatory drugs is critical, especially for the NLRP3 inflammasome that is triggered by a wide array of stimuli. We have developed three cell-based methods for quantifying inflammasome function: a NanoBRET™ NLRP3-specific target engagement assay, a caspase-1 activity assay and an IL-1β release assay. For the NLRP3 target engagement assay, cells are transfected with a NLRP3-Nanoluc construct and incubated with a cell-permeable, fluorescent NLRP3 binder (tracer), generating a bioluminescent resonance energy transfer (BRET) signal. The homogeneous caspase-1 and IL-1β assays can be run directly with cells in culture or with transferred culture medium, enabling application of both luminescent assays to the same cell wells via split-sample analysis. Using all three assays, we tested a series of reported NLRP3 inhibitors, including MCC950, oridonin, NBC6, NBC19, CY09, OXSi2 and OLT1177™ (dapansutrile). MCC950 inhibition of caspase-1 activity and IL-1β release was demonstrated in human and mouse cell models. We used LPS-primed THP-1 cells treated with nigericin for testing the series of inhibitors. The NLRP3 target engagement assay used HEK293 cells in suspension in non-binding plates. All three assays demonstrated good inhibition for MCC950, oridonin, NBC6, NBC19 and CY09 with rank order potency consistent with published results. We did not detect inhibition with OxSi2 or OLT1177™. These three assays enable screening for inflammasome antagonists and provide a mechanistic platform for characterizing NLRP3 inflammasome inhibitors.

Targeted Protein Degradation Phenotypic Studies Using HaloTag CRISPR/Cas9 Endogenous Tagging Coupled with HaloPROTAC3

To assess the role of a protein, protein loss phenotypic studies can be used, most commonly through mutagenesis RNAi or CRISPR knockout. Such studies have been critical for the understanding of protein function and the identification of putative therapeutic targets for numerous human disease states. However, these methodological approaches present challenges because they are not easily reversible, and if an essential gene is targeted, an associated loss of cell viability can potentially hinder further studies. Here we present a reversible and conditional live‐cell knockout strategy that is applicable to numerous proteins. This modular protein‐tagging approach regulates target loss at the protein, rather than the genomic, level through the use of HaloPROTAC3, which specifically degrades HaloTag fusion proteins via recruitment of the VHL E3 ligase component. To enable HaloTag‐mediated degradation of endogenous proteins, we provide protocols for HaloTag genomic insertion at the protein N or C terminus via CRISPR/Cas9 and use of HaloTag fluorescent ligands to enrich edited cells via Fluorescence‐Activated Cell Sorting (FACS). Using these approaches, endogenous HaloTag fusion proteins present in various subcellular locations can be degraded by HaloPROTAC3. As detecting the degradation of endogenous targets is challenging, the 11‐amino‐acid peptide tag HiBiT is added to the HaloTag fusion to allows the sensitive luminescence detection of HaloTag fusion levels without the use of antibodies. Lastly, we demonstrate, through comparison of HaloPROTAC3 degradation with that of another fusion tag PROTAC, dTAG‐13, that HaloPROTAC3 has a faster degradation rate and similar extent of degradation. © 2020 The Authors.

Basic Protocol 1: CRISPR/Cas9 insertion of HaloTag or HiBiT‐HaloTag

Basic Protocol 2: HaloPROTAC3 degradation of endogenous HaloTag fusions

Association of Age With Risk of Kidney Failure in Adults With Stage IV Chronic Kidney Disease in Canada

Importance

With population aging, the burden of many age-related chronic conditions, including kidney failure, is increasing globally.

Objective

To investigate the risks of kidney failure and death in adults with incident stage IV chronic kidney disease (CKD).

Design, Setting, and Participants

This population-based cohort study obtained data recorded between July 30, 2002, and March 31, 2014, from the linked laboratory and administrative data set of Alberta Health in Alberta, Canada. All adults of the province of Alberta with stage IV CKD (estimated glomerular filtration rate [eGFR] of 15-30 mL/min/1.73 m2) were eligible for inclusion. Included individuals were followed up from study entry until the date of kidney failure, death, or censoring, whichever occurred first. Observations were censored at the date of emigration from the province, the study end date (March 31, 2017), or at 10 years after study entry. Data analyses were performed from January 2020 to June 2020.

Main Outcomes and Measures

The primary outcome was kidney failure, defined as the earlier of either renal replacement (dialysis or kidney transplant) initiation or severe kidney impairment (eGFR <10 mL/min/1.73 m2). Incidence of stage IV CKD in Alberta was examined over time, along with the association between age at study entry and the competing risks of kidney failure and death. Cumulative incidence functions (95% CIs) were estimated to summarize absolute risks over time across categories of age, accounting for sex, diabetes, cardiovascular disease, eGFR, and albuminuria.

Results

The study included 30 801 adults (mean [SD] age, 76.8 [13.3] years; 17 294 women [56.1%]) with stage IV CKD. Of these, 5511 developed kidney failure (17.9%) and 16 285 died (52.9%). The incidence rate of stage IV CKD increased sharply with advancing age; the absolute risk of kidney failure decreased with advancing age, and the risk of death increased, especially in those aged 85 years or older. Compared with the 5-year risk of death, the 5-year risk of kidney failure was higher in people younger than 65 years, similar in people aged 65 to 74 years, and lower for older age groups. For those aged 75 years or older, the risk of death was much higher than the risk of kidney failure: 6-fold higher among those aged 75 to 84 years (0.51 [95% CI, 0.5-0.52] vs 0.09 [95% CI, 0.08-0.09]) and 25-fold higher among those aged 85 years or older (0.75 [95% CI, 0.74-0.76] vs 0.03 [95% CI, 0.02-0.03]). The risk of death was higher than the risk of kidney failure by 24-fold among those aged 85 to 94 years (0.73 [95% CI, 0.72-0.74] vs 0.03 [95% CI, 0.02-0.03]) and by 149-fold among those aged 95 years or older (0.89 [95% CI, 0.87-0.92] vs <0.01 [95% CI, <0.01 to 0.01]).

Conclusions and Relevance

This study found that, although the incidence rate of stage IV CKD increased with advancing age, the absolute risk of kidney failure decreased. Unlike other age-related conditions, the expected increase in the burden of kidney failure in the older adults may be less dramatic than expected.

Influence of Mortality on Estimating the Risk of Kidney Failure in People with Stage 4 CKD

BACKGROUND

Most kidney failure risk calculators are based on methods that censor for death. Because mortality is high in people with severe, nondialysis-dependent CKD, censoring for death may overestimate their risk of kidney failure.

METHODS

Using 2002-2014 population-based laboratory and administrative data for adults with stage 4 CKD in Alberta, Canada, we analyzed the time to the earliest of kidney failure, death, or censoring, using methods that censor for death and methods that treat death as a competing event factoring in age, sex, diabetes, cardiovascular disease, eGFR, and albuminuria. Stage 4 CKD was defined as a sustained eGFR of 15-30 ml/min per 1.73 m².

RESULTS

Of the 30,801 participants (106,447 patient-years at risk; mean age 77 years), 18% developed kidney failure and 53% died. The observed risk of the combined end point of death or kidney failure was 64% at 5 years and 87% at 10 years. By comparison, standard risk calculators that censored for death estimated these risks to be 76% at 5 years and >100% at 7.5 years. Censoring for death increasingly overestimated the risk of kidney failure over time from 7% at 5 years to 19% at 10 years, especially in people at higher risk of death. For example, the overestimation of 5-year absolute risk ranged from 1% in a woman without diabetes, cardiovascular disease, or albuminuria and with an eGFR of 25 ml/min per 1.73 m² (9% versus 8%), to 27% in a man with diabetes, cardiovascular disease, albuminuria >300 mg/d, and an eGFR of 20 ml/min per 1.73 m² (78% versus 51%).

CONCLUSIONS

Kidney failure risk calculators should account for death as a competing risk to increase their accuracy and utility for patients and providers.

The Influence of Age on the Likelihood of Catheter-Free Fistula Use in Hemodialysis Patients

Background:

Clinical practice guidelines recommend arteriovenous fistulas as the preferred form of vascular access for hemodialysis. However, some studies have suggested that older age is associated with poorer fistula outcomes.

Objective:

We assessed the impact of age on the outcomes of fistula creation and access-related procedures.

Design:

This was a prospective cohort study using data collected as part of the Dialysis Measurement Analysis and Reporting (DMAR) system.

Setting:

Participating Canadian dialysis programs, including Southern Alberta Renal Program, Manitoba Renal Program, Sunnybrook Health Sciences Centre (Toronto, Ontario), London Health Sciences Centre (London, Ontario), and The Ottawa Hospital (Ottawa, Ontario).

Patients:

Incident hemodialysis patients aged 18 years and older who started dialysis between January 1, 2004, and May 31, 2012.

Measurements:

The primary outcome was the proportion of all first fistula attempts that resulted in catheter-free fistula use, defined as independent use of a fistula for hemodialysis (ie, no catheter in place). Secondary outcomes included the time to catheter-free fistula use among patients with a fistula creation attempt, total number of days of catheter-free fistula use, and the proportion of a patient’s hemodialysis career spent with an independently functioning fistula (ie, catheter-free fistula use).

Methods:

We compared patient characteristics by age group, using t tests or Wilcoxon rank sum tests, and chi-square or Fisher exact tests, as appropriate. Logistic and fractional logistic regression were used to estimate the odds of achieving catheter-free fistula use by age group and the proportion of dialysis time spent catheter-free, respectively.

Results:

A total of 1091 patients met our inclusion criteria (567 age ≥ 65; 524 age < 65). Only 57% of first fistula attempts resulted in catheter-free fistula use irrespective of age (adjusted odds ratio [OR]_≥65vs<65: 1.01; P = .93). The median time from hemodialysis start to catheter-free use of the first fistula did not differ by age when grouped into fistulas attempted pre- and post-dialysis initiation. The adjusted rates of access-related procedures were comparable (incidence rate ratio [IRR]_≥65vs<65: 0.95; P = .32). The median percentage of follow-up time spent catheter-free was similar and low in patients who attempted fistulas (<65 years: 19% vs ≥65 years: 21%; P = .85).

Limitations:

The relatively short follow-up time may have underestimated the benefits of fistula creation and the observational study design precludes inferences about causality.

Conclusions:

In our study, older patients who underwent a fistula attempt were just as likely as younger patients to achieve catheter-free fistula use, within a similar time frame, and while requiring a similar number of access procedures. However, the minority of dialysis time was spent catheter-free.

The Risk of Major Hemorrhage with CKD

New staging systems for CKD account for both reduced eGFR and albuminuria; whether each measure associates with greater risk of hemorrhage is unclear. In this retrospective cohort study (2002-2010), we grouped 516,197 adults ≥40 years old by eGFR (≥90, 60 to <90, 45 to <60, 30 to <45, 15 to <30, or <15 ml/min per 1.73 m(2)) and urine albumin-to-creatinine ratio (ACR; >300, 30-300, or <30 mg/g) to examine incidence of hemorrhage. The 3-year cumulative incidence of hemorrhage increased 20-fold across declining eGFR and increasing urine ACR groupings (highest eGFR/lowest ACR: 0.5%; lowest eGFR/highest ACR: 10.1%). Urine ACR altered the association of eGFR with hemorrhage (P<0.001). In adjusted models using the highest eGFR/lowest ACR grouping as the referent, patients with eGFR=15 to <30 ml/min per 1.73 m(2) had adjusted relative risks of hemorrhage of 1.9 (95% confidence interval [95% CI], 1.5 to 2.4) with the lowest ACR and 3.7 (95% CI, 3.0 to 4.5) with the highest ACR. Patients with the highest eGFR/highest ACR had an adjusted relative risk of hemorrhage of 2.3 (95% CI, 1.8 to 2.9), comparable with the risk for patients with the lowest eGFR/lowest ACR. The associations attenuated but remained significant after adjustment for anticoagulant and antiplatelet use in patients ≥66 years old. The risk of hemorrhage differed by urine ACR in high risk subgroups. Our data show that declining eGFR and increasing albuminuria each independently increase hemorrhage risk. Strategies to reduce hemorrhage events among patients with CKD are warranted.

Identification of CASZ1 NES reveals potential mechanisms for loss of CASZ1 tumor suppressor activity in neuroblastoma

As a transcription factor, localization to the nucleus and the recruitment of cofactors to regulate gene transcription is essential. Nuclear localization and nucleosome remodeling and histone deacetylase (NuRD) complex binding are required for the zinc-finger transcription factor CASZ1 to function as a neuroblastoma (NB) tumor suppressor. However, the critical amino acids (AAs) that are required for CASZ1 interaction with NuRD complex and the regulation of CASZ1 subcellular localization have not been characterized. Through alanine scanning, immunofluorescence cell staining and co-immunoprecipitation, we define a critical region at the CASZ1 N terminus (AAs 23-40) that mediates the CASZ1b nuclear localization and NuRD interaction. Furthermore, we identified a nuclear export signal (NES) at the N terminus (AAs 176-192) that contributes to CASZ1 nuclear-cytoplasmic shuttling in a chromosomal maintenance 1-dependent manner. An analysis of CASZ1 protein expression in a primary NB tissue microarray shows that high nuclear CASZ1 staining is detected in tumor samples from NB patients with good prognosis. In contrast, cytoplasmic-restricted CASZ1 staining or low nuclear CASZ1 staining is found in tumor samples from patients with poor prognosis. These findings provide insight into mechanisms by which CASZ1 regulates transcription, and suggests that regulation of CASZ1 subcellular localization may impact its function in normal development and pathologic conditions such as NB tumorigenesis.

Esophageal stenting for treatment of refractory benign esophageal strictures in dogs

BACKGROUND

Benign esophageal strictures can recur despite multiple dilatation procedures and palliative management can be challenging.

OBJECTIVE

To describe the technique and determine the outcome of esophageal stenting for treatment of refractory benign esophageal strictures (RBES) in dogs.

ANIMALS

Nine dogs with RBES.

METHODS

Retrospective review of records for dogs with RBES. Indwelling intraluminal esophageal stents were placed transorally with endoscopy, fluoroscopic guidance, or both. Follow-up information was obtained via medical record or telephone interview.

RESULTS

Nine dogs had 10 stents placed including biodegradable stents (BDS) (6/10), self-expanding metallic stents (SEMS) (3/10), and a self-expanding plastic stent (SEPS) (1/10). All dogs had short-term improved dysphagia. Complications included ptyalism, apparent nausea, gagging, vomiting, or regurgitation (8/9), confirmed recurrence of stricture (6/9), stent migration (3/9), stent shortening (1/9), megaesophagus (1/9), incisional infection (1/9), and tracheal-esophageal fistula (1/9). Eight of 9 dogs required intervention because of the complications of which 4 of 8 dogs were eventually euthanized because of stent-related issues. One dog was lost to follow-up examination.

CONCLUSIONS AND CLINICAL IMPORTANCE

Findings suggest that esophageal stent placement was safe and technically effective, but unpredictably tolerated in dogs with RBES. If a stent is placed, dogs should be monitored carefully for stent migration, dissolution of absorbable stents, and recurrence of strictures.

Placental abruption occurring soon after labor combined spinal-epidural analgesia

We present a case of placental abruption necessitating emergency cesarean section in an otherwise uncomplicated patient soon after initiation of combined spinal-epidural analgesia in labor. Administration of spinal opioids has the potential to cause fetal bradycardia due to uterine hypertonicity following rapid onset of analgesia. In this case, a previously bloody show before placement of combined spinal-epidural analgesia may have been evidence of a small abruption. We hypothesize that uterine hypertonicity following administration of spinal opioids may have hastened the development of an existing placental abruption.

Cardiovascular disease in kidney donors: matched cohort study

OBJECTIVE

To determine whether people who donate a kidney have an increased risk of cardiovascular disease.

DESIGN

Retrospective population based matched cohort study.

PARTICIPANTS

All people who were carefully selected to become a living kidney donor in the province of Ontario, Canada, between 1992 and 2009. The information in donor charts was manually reviewed and linked to provincial healthcare databases. Matched non-donors were selected from the healthiest segment of the general population. A total of 2028 donors and 20,280 matched non-donors were followed for a median of 6.5 years (maximum 17.7 years). Median age was 43 at the time of donation (interquartile range 34-50) and 50 at the time of follow-up (42-58).

MAIN OUTCOME MEASURES

The primary outcome was a composite of time to death or first major cardiovascular event. The secondary outcome was time to first major cardiovascular event censored for death.

RESULTS

The risk of the primary outcome of death and major cardiovascular events was lower in donors than in non-donors (2.8 v 4.1 events per 1000 person years; hazard ratio 0.66, 95% confidence interval 0.48 to 0.90). The risk of major cardiovascular events censored for death was no different in donors than in non-donors (1.7 v 2.0 events per 1000 person years; 0.85, 0.57 to 1.27). Results were similar in all sensitivity analyses. Older age and lower income were associated with a higher risk of death and major cardiovascular events in both donors and non-donors when each group was analysed separately.

CONCLUSIONS

The risk of major cardiovascular events in donors is no higher in the first decade after kidney donation compared with a similarly healthy segment of the general population. While we will continue to follow people in this study, these interim results add to the evidence base supporting the safety of the practice among carefully selected donors.

Acute dialysis risk in living kidney donors

It is crucial to carefully screen donors and essential to resist compromises. If this is respected the survival, the co-morbidity, ESRD or even acute renal failure, as shown by Lam et al. in the current issue of this journal, appear to be similar to those in the general population.

Background

Reduced kidney function confers a higher risk of acute kidney injury at the time of an inciting event, such as sepsis. Whether the same is true in those with reduced renal mass from living kidney donation is unknown.

Methods

We conducted a population-based matched cohort study of all living kidney donors in the province of Ontario, Canada who underwent donor nephrectomy from 1992 to 2009. We manually reviewed the medical records of these living kidney donors and linked this information to provincial health care databases. Non-donors were selected from the healthiest segment of the general population.

Results

There were 2027 donors and 20 270 matched non-donors. The median age was 43 years (interquartile range 34–50) and individuals were followed for a median of 6.6 years (maximum 17.7 years). The primary outcome was acute dialysis during any hospital stay. Reasons for hospitalization included infectious diseases, cardiovascular diseases and hematological malignancies. Only one donor received acute dialysis in follow-up (6.5 events per 100 000 person-years), a rate which was statistically no different than 14 non-donors (9.4 events per 100 000 person-years).

Conclusions

These results are reassuring for the practice of living kidney donation. Longer follow-up of this and other donor cohorts will provide more precise estimates about this risk.

C. elegans HLH-2/E/Daughterless controls key regulatory cells during gonadogenesis

The Caenorhabditis elegans distal tip cell (DTC) provides a niche for germline stem cells in both hermaphrodites and males. The hermaphrodite distal tip cell (hDTC) also provides "leader" function to control gonadal elongation and shape, while in males, leader function is allocated to the linker cell (LC). Therefore, the male distal tip cell (mDTC) serves as a niche but not as a leader. The C. elegans homolog of E/Daughterless, HLH-2, was previously implicated in hDTC specification. Here we report that HLH-2 is also critical for hDTC maintenance, hDTC niche function and hDTC expression of a lag-2/DSL ligand reporter. We also find that HLH-2 functions in males to direct linker cell specification and to promote both mDTC maintenance and the mDTC niche function. We conclude that HLH-2 functions in both sexes to promote leader cell specification and DTC niche function.

Headaches and migraines are associated with an increased risk of preeclampsia in Peruvian women

BACKGROUND

Migraine, a common chronic-intermittent disorder of idiopathic origin characterized by severe debilitating headaches and autonomic nervous system dysfunction, and preeclampsia, a hypertensive disorder of pregnancy, share many common epidemiological and pathophysiological characteristics. Both conditions are associated with higher subsequent risk of ischemic stroke. Moreover, endothelial dysfunction, platelet activation, hyper-coagulation, and inflammation are common to both disorders. We assessed the risk for preeclampsia in relation to the maternal history of migraine before and during pregnancy in Peruvian women.

METHODS

Cases consisted of 339 women with preeclampsia, and controls were 337 normotensive women. During in-person interviews conducted at delivery, women were asked whether they had physician-diagnosed migraines, and they were asked questions that allowed for headaches and migraines to be classified according to criteria established by the International Headache Society (IHS). Logistic regression procedures were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

A history of any headache before or during pregnancy was associated with a 2.4-fold increased risk for preeclampsia (OR = 2.4; 95% CI 1.7-3.3). Women classified as having migraines that began prior to pregnancy had a 3.5-fold increased risk for preeclampsia (95% CI 1.9-6.4) as compared with those who reported no migraines. Women with migraines during pregnancy had a fourfold increased risk of preeclampsia (OR = 4.0, 95% CI 1.9-8.2) compared with non-migraineurs.

CONCLUSIONS

Our findings are consistent with previous reports and we have extended them to the Peruvian population. Prospective cohort studies, however, are needed to more rigorously evaluate the extent to which migraines and/or its treatments are associated with the occurrence of preeclampsia.

Wnt signaling and CEH-22/tinman/Nkx2.5 specify a stem cell niche in C. elegans

Wnt signaling regulates many aspects of metazoan development, including stem cells. In C. elegans, Wnt/MAPK signaling controls asymmetric divisions. A recent model proposed that the POP-1/TCF DNA binding protein works together with SYS-1/beta-catenin to activate transcription of target genes in response to Wnt/MAPK signaling. The somatic gonadal precursor (SGP) divides asymmetrically to generate distal and proximal daughters of distinct fates: only its distal daughter generates a distal tip cell (DTC), which is required for stem cell maintenance. No DTCs are produced in the absence of POP-1/TCF or SYS-1/beta-catenin, and extra DTCs are made upon overexpression of SYS-1/beta-catenin. Here we report that POP-1/TCF and SYS-1/beta-catenin directly activate transcription of ceh-22/nkx2.5 isoforms in SGP distal daughters, a finding that confirms the proposed model of Wnt/MAPK signaling. In addition, we demonstrate that the CEH-22/Nkx2.5 homeodomain transcription factor is a key regulator of DTC specification. We speculate that these conserved molecular regulators of the DTC niche in nematodes may provide insight into specification of stem cell niches more broadly.

Identification of sex chromosome molecular markers using RAPDs and fluorescent in situ hybridization in rainbow trout

The goal of this work is to identify molecular markers associated with the sex chromosomes in rainbow trout to study the mode of sex determination mechanisms in this species. Using the RAPD assay and bulked segregant analysis, two markers were identified that generated polymorphic bands amplifying preferentially in males of the Mount Lassen and Scottish strains of rainbow trout. Chromosomal localization using fluorescent in situ hybridization of a 900 bp probe developed from one of these markers revealed a brightly defined signal on a chromosome that could morphologically be classified as the Y chromosome.

A derivative of bovine herpesvirus 1 (BoHV-1) UL3.5 lacking the last forty amino acids inhibits replication of BoHV-1

Bovine herpesvirus 1 (BoHV-1) UL3.5 is a tegument protein that interacts with BoHV-1 alpha-transinducing factor alphaBTIF). In this report, we show that a truncated UL3.5 lacking the last 40 amino acids (C40UL3.5) inhibited replication of BoHV-1. Stable expression of C40UL3.5 in MDBK cells inhibited replication of BoHV-1 300- to 500-fold in plaque assays. This inhibitory effect was specific for BoHV-1 as cells expressing C40UL3.5 supported replication of pseudorabies virus (species Suid herpesvirus 1, SuHV-1) and herpes simplex virus (species Human herpesvirus 1, HHV-1) to normal levels. In contrast, a truncated UL3.5 which lacked the first 20 amino acids and did not interact with alphaBTIF did not inhibit BoHV-1 replication. In the C40UL3.5-expressing cells infected with BoHV-1, expression of the viral immediate early gene BICP4 and the early protein gB were reduced and delayed. C40UL3.5, when either transiently or stably expressed, inhibited alphaBTIF-mediated transactivation of a BoHV-1 immediate-early promoter. C40UL3.5 may be useful for constructing transgenic cattle resistant to infection by BoHV-1.

High physiological levels of LMP1 result in phosphorylation of eIF2 alpha in Epstein-Barr virus-infected cells

LMP1 is an Epstein-Barr virus (EBV)-encoded membrane protein essential for the proliferation of EBV-infected lymphoblasts (E. Kilger, A. Kieser, M. Baumann, and W. Hammerschmidt, EMBO J. 17:1700-1709, 1998). LMP1 also inhibits gene expression and induces cytostasis in transfected cells when it is expressed at levels as little as twofold higher than the average for EBV-positive lymphoblasts (M. Sandberg, A. Kaykas, and B. Sugden, J. Virol. 74:9755-9761, 2000; A. Kaykas and B. Sugden, Oncogene 19:1400-1410, 2000). We have found that in three different clones of EBV-infected lymphoblasts the levels of expression of LMP1 in individual cells in each clone ranged over 100-fold. This difference is due to a difference in levels of the LMP1 transcript. In these clones, cells expressing high levels of LMP1 incorporated less BrdU. We also found that induction of expression of LMP1 or of a derivative of LMP1 with its transmembrane domain fused to green fluorescent protein instead of its carboxy-terminal signaling domain resulted in phosphorylation of eIF2 alpha in EBV-negative Burkitt's lymphoma cells. This induction of phosphorylation of eIF2 alpha was also detected in EBV-infected lymphoblasts, in which high levels of LMP1 correlated with high levels of phosphorylation of eIF2 alpha. Our results indicate that inhibition of gene expression and of cell proliferation by LMP1 occurs normally in EBV-infected cells.

LMP1, a viral relative of the TNF receptor family, signals principally from intracellular compartments

Latent membrane protein 1 (LMP1) is an Epstein-Barr virus (EBV)-encoded, ligand-independent receptor that mimics CD40. We report here that LMP1 signals principally from intracellular compartments. LMP1 associates simultaneously with lipid rafts and with its signaling molecules, tumor necrosis factor-receptor (TNF-R)-associated factors (TRAFs) and TNF-R1-associated death domain protein (TRADD) intracellularly, although it can be detected at low levels at the plasma membrane, indicating that most of LMP1's signaling complex resides in intracellular compartments. LMP1's signaling is independent of its accumulation at the plasma membrane in different cells, and as demonstrated by a mutant of LMP1 which has significantly reduced localization at the plasma membrane yet signals as efficiently as does wild-type LMP1. The fusion of the transmembrane domain of LMP1 to signaling domains of CD40, TNF-R1 and Fas activates their signaling; we demonstrate that a fusion of LMP1 with CD40 recruits TRAF2 intracellularly. Our results imply that members of the TNF-R family can signal from intracellular compartments containing lipid rafts and may do so when they act in autocrine loops.

Patients with and without intellectual disability seeking outpatient psychiatric services: diagnoses and prescribing pattern

BACKGROUND

The present study examined the presenting problem of psychiatric outpatients, and resulting diagnostic and prescribing patterns, comparing patients with intellectual disability (ID) with non-ID (N-ID) patients seen in the same clinic.

METHODS

This study was a retrospective medical chart review of information in the first psychiatric diagnostic evaluation for the most recent 100 adult patients with mild ID, 100 patients with moderate, severe or profound ID, and 100 matching N-ID patients.

RESULTS

There were significant differences in rates of medical illness, disabilities, history of marriage, children, independent living, and family history of psychiatric and neurological disorders. Individuals with ID were more likely to present with aggression, self-injurious behaviour or physical complaints, whereas N-ID subjects presented more frequently with depression and anxiety complaints. For all groups, depressive disorders were the most frequent class of diagnoses. For those with ID, antipsychotics were used in 32% of subjects, with mood stabilizers in 28% and antidepressants in 27%. The N-ID subjects were most frequently prescribed antidepressants (40%) and anxiolytics (22%). Polypharmacy did not differ significantly among groups.

CONCLUSIONS

Psychiatric practitioners relied on the diagnostic examination to formulate their diagnosis, whereas the chief complaint reflected the view of caregivers of the subjects with ID. In contrast to previous studies, outpatient providers frequently diagnosed depression, and the prescribing pattern showed increased usage of antidepressants and mood stabilizers.

CD40 and its viral mimic, LMP1: similar means to different ends

CD40 is an important regulator of diverse aspects of the immune response including the T-cell-dependent humoral immune response, the development of antigen-presenting cells (APCs) and inflammation. Latent membrane protein 1 (LMP1), a protein encoded by Epstein-Barr Virus (EBV), appears to mimic CD40 in multiple ways. CD40 and LMP1 bind similar sets of cellular signalling proteins and activate overlapping signalling pathways. Despite many similarities shared between CD40 and LMP1, they also differ substantively. In this review, we will compare and contrast the signalling mediated by CD40 and LMP1.

Characterization of sex chromosomes in rainbow trout and coho salmon using fluorescence in situ hybridization (FISH)

With the aim of characterizing the sex chromosomes of rainbow trout (Oncorhynchus mykiss) and to identify the sex chromosomes of coho salmon (O. kisutch), we used molecular markers OmyP9, 5S rDNA, and a growth hormone gene fragment (GH2), as FISH probes. Metaphase chromosomes were obtained from lymphocyte cultures from farm specimens of rainbow trout and coho salmon. Rainbow trout sex marker OmyP9 hybridizes on the sex chromosomes of rainbow trout, while in coho salmon, fluorescent signals were localized in the medial region of the long arm of one subtelocentric chromosome pair. This hybridization pattern together with the hybridization of a GH2 intron probe on a chromosome pair having the same morphology, suggests that a subtelocentric pair could be the sex chromosomes in this species. We confirm that in rainbow trout, one of the two loci for 5S rDNA genes is on the X chromosome. In males of this species that lack a heteromorphic sex pair (XX males), the 5S rDNA probe hybridized to both subtelocentrics. This finding is discussed in relation to the hypothesis of intraspecific polymorphism of sex chromosomes in rainbow trout.

Bovine herpesvirus 1 U(L)3.5 interacts with bovine herpesvirus 1 alpha-transinducing factor

The bovine herpesvirus 1 (BHV-1) U(L)3.5 gene encodes a 126-amino-acid tegument protein. Homologs of U(L)3.5 are present in some alphaherpesviruses and have 20 to 30% overall amino acid homology that is concentrated in the N-terminal 50 amino acids. Mutant pseudorabies virus lacking U(L)3.5 is deficient in viral egress but can be complemented by BHV-1 U(L)3.5 (W. Fuchs, H. Granzow, and T. C. Mettenleiter, J. Virol. 71:8886-8892, 1997). The function of BHV-1 U(L)3.5 in BHV-1 replication is not known. To get a better understanding of its function, we sought to identify the proteins that interact with the BHV-1 U(L)3.5 protein. By using an in vitro pull-down assay and matrix-assisted laser desorption ionization mass spectrometry analysis, we identified BHV-1 alpha-transinducing factor (alphaBTIF) as a BHV-1 U(L)3. 5-interacting protein. The interaction was verified by coimmunoprecipitation from virus-infected cells using an antibody to either protein, by indirect immunofluorescence colocalization in both virus-infected and transfected cells, and by the binding of in vitro-translated proteins. In virus-infected cells, U(L)3.5 and alphaBTIF colocalized in a Golgi-like subcellular compartment late in infection. In transfected cells, they colocalized in the nucleus. Deletion of 20 amino acids from the N terminus of U(L)3.5, but not 40 amino acids from the C terminus, abolished the U(L)3.5-alphaBTIF interaction both in vitro and in vivo. The interaction between U(L)3. 5 and alphaBTIF may be important for BHV-1 maturation and regulation of alphaBTIF transactivation activity.

Adrenaline upregulates monocyte L-selectin in vitro

OBJECTIVE

Although surface adhesion molecules mediate leucocyte-endothelial interactions at sites of inflammation, relatively little is known of the factors which increase the expression of L-selectin in circulating leucocytes. The expression of leucocyte L-selectin increases during acute stress events such as injury and is temporally related to an early neuroendocrine response. This study investigates whether adrenaline increases the expression of L-selectin on monocytes, neutrophils and lymphocytes in vitro and whether these effects are mediated via beta-adrenoceptors.

METHODS

A total of 20 ml of blood was withdrawn from 28 healthy volunteers (21 males) with a mean age of 29 years (range 23-67 years). Adrenaline at physiological doses mimicking trauma (0-200 nmol/l) was added to whole blood prior to immunofluorescent staining and analysis by flow cytometry. Propranolol (50 microl of 2 x 10(-5) M) was also added to separate tubes prior to incubation with adrenaline. Saline (40 microl 0.9% solution) was used as a control. Expression is described firstly as percentage of cells expressing L-selectin and secondly as average intensity (mean channel fluorescence, mcf) per cell expressing CD62L. Summary measures were used to analyse the data.

RESULTS

A significant increase in both the percentage of monocytes expressing L-selectin and mean channel fluorescence of L-selectin was evident with adrenaline in vitro (P < 0.0001). Maximal increases occurred at 100 nmol/l adrenaline when a 9% increase in the percentage of monocytes expressing L-selectin and a 23% increase in mean channel fluorescence were observed. These effects were both blocked by propranolol (P < 0.0001). No significant differences were observed for neutrophils or lymphocytes except for a slight increase in the percent neutrophils expressing L-selectin, and a small decreasing trend in percent lymphocytes expressing L-selectin.

CONCLUSIONS

Adrenaline upregulates the surface expression of L-selectin on monocytes in vitro, an effect which is partially mediated by beta-adrenoceptors. As monocytes initiate early aspects of the inflammatory response, these findings suggest that beta-blockade may have an inhibitory role for certain aspects of leucocyte trafficking.

Dealing with fatigue: the importance of health-related action patterns

Fatigue complaints are frequent and important problems affecting people's quality of life and creating puzzles for the General Practitioners they consult. Little is known about what actions people undertake to deal with fatigue, and even less about their success. As revealed by multivariate analyses health-related action patterns can classify people as being particularly successful or unsuccessful in dealing with their complaints of chronic fatigue. This study suggests that a few actions applied in combination and in a concentrated manner constitute the basis for a successful action pattern. The number, type and predictive power of the relevant actions vary depending on the persons in question: having chronic diseases or not and being under 44 or over 44 years old.

Early HCV RNA values after interferon predict response

The aim of this study is to determine in patients infected with hepatitis C virus (HCV) whether early HCV RNA measurements at 48 hr following standard doses of interferon-alpha (IFN-alpha) (3 million IU) would predict response during six months of therapy. Twenty-three patients with HCV were treated with IFN-alpha 3 million IU three times a week and HCV RNA levels were quantified by branched-chain (b-)DNA analysis at baseline and 24 and 48 hr following IFN-alpha and at one, three, and six months. Mean baseline HCV RNA levels significantly declined from 6.0 +/- 1.6 Meq/ml at baseline to 2.4 +/- 0.7 Meq/ml 24 hr after IFN-alpha. However, HCV RNA values increased to 4.3 +/- 1.1 Meq/ml by 48 hr. Mean HCV RNA values at one and six months were not significantly lower than 48-hr values. In six patients in whom HCV RNA was negative by bDNA at 48 hr, three were negative by polymerase chain reaction at six months. Of the 17 patients who were positive by bDNA at 48 hr, all were positive at one and three months; and in the nine of nine who continued therapy for six months, there was no further decrease in HCV RNA levels. In patients receiving standard doses of IFN-alpha (3 million IU), serum RNA values 48 hr after the first injection predict long-term response.

Association of obesity, gender, age and occupation with carpal tunnel syndrome

BACKGROUND

The present study determines the association of obesity, gender, age and occupation in patients with carpal tunnel syndrome (CTS) in a New Zealand population.

METHODS

Analysis of questionnaires and clinical review of patients who had undergone surgical decompression of the median nerve in the carpal tunnel.

RESULTS

The age and gender distribution of 655 hands (512 patients) that had undergone carpal tunnel release (CTR) were compared with the age and gender distribution of the New Zealand population. The results indicate that the 3-year-period prevalence of CTS in females is more than double that in males. Proportionally there were more patients over age 55 than in the general population. The findings also indicate that, proportionally, six times the number of females who worked in moderate manual work underwent CTR compared with the general female population and proportionally twice the number of males who worked in heavy office/clerical work underwent CTR compared with the general male population. It was also found that CTR patients are twice as likely to be overweight (body mass index [BMI] > 25) than the general population and female patients are twice as likely to be obese (BMI > 30) than the general population.

CONCLUSIONS

Carpal tunnel syndrome is more than twice as common in females as it is in males, and patients aged more than 55 years are more likely to suffer from CTS. Females with CTS are more likely to work in moderate manual work and males with CTS are more likely to work in heavy office/clerical work. Obesity and CTS are related statistically.

Results of open carpal tunnel release: a comprehensive, retrospective study of 188 hands

BACKGROUND

Many recent reports of the results of decompression of the median nerve in the carpal tunnel have concentrated on only one aspect of recovery (numbness, grip etc.), and there are no reports of a comprehensive study of outcome. The aim of the present study was to review comprehensively the results of the direct visualization method of decompression of the carpal tunnel and to compare them with the published results of endoscopic release.

METHODS

Patients' perceptions of the severity of pain, numbness and paraesthesiae due to carpal tunnel syndrome (CTS), before and after open carpal tunnel release (CTR) in 188 hands were reviewed retrospectively at a minimum time of follow-up of 18 months. Motor and sensory testing, provocation testing and measurement of scar tenderness in 135 hands were performed at a clinical review.

RESULTS

Subjective results showed that 70% experienced a reduction in the severity of pain after CTR, 78% of hands experienced a reduction in the severity of paraesthesiae and 77% experienced a reduction in the severity of numbness. A total of 49% had improvements in all three symptoms after CTR. At the clinical review, sensory testing revealed that 59% of hands had normal or slightly diminished light touch, 35% had normal static two-point discrimination and 61% had normal dynamic two-point discrimination. Results for Tinel's test, Phalen's test and pressure provocation testing were positive in 10% of hands. There was no scar tenderness in 38%, no persisting thenar atrophy in 90%. Normal grip strength was found in 93% and 91% had normal pinch strength.

CONCLUSIONS

It was concluded that open carpal tunnel release remains a safe and reliable treatment for carpal tunnel syndrome. The very low incidence of serious complications from the open technique of CTR, when compared with endoscopic CTR as published by different authors in the literature, and the comparable clinical results, appears to make the open technique a safer and preferable option. However, a properly controlled trial of both techniques is necessary to compare them.

Diagnosis and management of fulminant hepatic failure

Fulminant hepatic failure is defined as the development of hepatic encephalopathy within 8 weeks of the onset of illness. While there are many causes of FHF, viral hepatitis, particularly hepatitis B, remains the most common etiology. Several drugs and toxins can also lead to FHF, most notably acetaminophen. Even with improvements in ICU care, mortality remains very high for these patients. Conservative management focuses on invasive monitoring and the prevention and treatment of complications like cerebral edema, infection, renal failure, and coagulopathy. Only orthotopic liver transplantation has reduced mortality from 80% to 30% to 50%. Therefore, the goals of management and treatment now include determining which patients are appropriate for liver transplant and finding a donor in a timely fashion.