Peptide-mediated delivery of CRISPR enzymes for the efficient editing of primary human lymphocytes

CRISPR-mediated genome editing of primary human lymphocytes is typically carried out via electroporation, which can be cytotoxic, cumbersome and costly. Here we show that the yields of edited primary human lymphocytes can be increased substantially by delivering a CRISPR ribonucleoprotein mixed with an amphiphilic peptide identified through screening. We evaluated the performance of this simple delivery method by knocking out genes in T cells, B cells and natural killer cells via the delivery of Cas9 or Cas12a ribonucleoproteins or an adenine base editor. We also show that peptide-mediated ribonucleoprotein delivery paired with an adeno-associated-virus-mediated homology-directed repair template can introduce a chimaeric antigen receptor gene at the T-cell receptor α constant locus, and that the engineered cells display antitumour potency in mice. The method is minimally perturbative, does not require dedicated hardware, and is compatible with multiplexed editing via sequential delivery, which minimizes the risk of genotoxicity. The peptide-mediated intracellular delivery of ribonucleoproteins may facilitate the manufacturing of engineered T cells.

People's Perception of Well-Being during the COVID-19 Pandemic: A Case Study in Japan

This study aims to examine people's perception of well-being during the COVID-19 pandemic in Japan and quantitatively clarify key factors towards realizing evidence-based policymaking. In March 2022, 400 participants responded to a survey conducted through Rakuten Insight. The authors applied an ordinal logistic regression (OLR), followed by principal component analysis (PCA), to create a new compound indicator (CI) to represent people's perception of well-being during the pandemic in addition to ordinary least squares (OLS) regression with a forward-backward stepwise selection method, where the dependent variable is the principal component score of the first principal component (PC1), while the independent variables are the same as the abovementioned OLR. Consequently, while analyzing OLR, some independent variables showed statistical significance, while the CI provided an option to grasp people's perception of well-being. Furthermore, family structure was statistically significant in all cases of OLR and OLS. Moreover, in terms of the standardized coefficients (beta) of OLS, the family structure had the greatest impact on the CI. Based on the study results, the authors advocate that the Japanese government should pay more attention to single-person households affected by the COVID-19 pandemic.

Experimental comparison of DSB and CS-DSB mmW formats over a hybrid fiber and FSO fronthaul network for 5G

The telecommunication world is experiencing the 5th generation (5G) networks deployment including the use of millimeter wave (mmW) frequency bands to satisfy capacity demands. This leads to the extensive use of optical communications, especially the optical fiber connectivity at the last mile access and the edge networks. In this paper we outline fiber and free space optics (FSO) technologies for use as part of the 5G optical fronthaul network. We investigate two different mmW transmission schemes based on (i) the conventional analog radio over fiber transmission using one Mach-Zehnder modulator (MZM) with double sideband (DSB) optical modulation, and (ii) an optical-based frequency doubling with one MZM biased at the null point to introduce carrier suppression DSB (CS DSB) transmission and second MZM used for data modulation. Both systems are assessed in terms of the error vector magnitude, signal-to-noise ratio, dynamic range and phase noise. We consider a configuration for the fronthaul network in the frequency range 2 (FR2) at 27 and 39 GHz with the scale of bandwidth up to 400 MHz with M-quadrature amplitude modulation and quadrature phase shift keying. Results are also shown for FR1 at 3.5 GHz. Moreover, we investigate for the first time the 5G new radio signal transmission under strong turbulence conditions and show the turbulence-induced FSO link impairment. We finally demonstrate the CS DSB scheme performs well under chromatic dispersion-induced fading for the frequency up to 40 GHz and single mode fiber length of 30 km, whereas the DSB format seems more appropriate for an antenna seamless transmission.

Abcc1 and Ggt5 support lymphocyte guidance through export and catabolism of S-geranylgeranyl-l-glutathione

P2RY8 promotes the confinement and growth regulation of germinal center (GC) B cells, and loss of human P2RY8 is associated with B cell lymphomagenesis. The metabolite S-geranylgeranyl-l-glutathione (GGG) is a P2RY8 ligand. The mechanisms controlling GGG distribution are poorly understood. Here, we show that gamma-glutamyltransferase-5 (Ggt5) expression in stromal cells was required for GGG catabolism and confinement of P2RY8-expressing cells to GCs. We identified the ATP-binding cassette subfamily C member 1 (Abcc1) as a GGG transporter and showed that Abcc1 expression by hematopoietic cells was necessary for P2RY8-mediated GC confinement. Furthermore, we discovered that P2RY8 and GGG negatively regulated trafficking of B and T cells to the bone marrow (BM). P2RY8 loss-of-function human T cells increased their BM homing. By defining how GGG distribution was determined and identifying sites of P2RY8 activity, this work helps establish how disruptions in P2RY8 function contribute to lymphomagenesis and other disease states.

Constrained chromatin accessibility in PU.1-mutated agammaglobulinemia patients

The pioneer transcription factor (TF) PU.1 controls hematopoietic cell fate by decompacting stem cell heterochromatin and allowing nonpioneer TFs to enter otherwise inaccessible genomic sites. PU.1 deficiency fatally arrests lymphopoiesis and myelopoiesis in mice, but human congenital PU.1 disorders have not previously been described. We studied six unrelated agammaglobulinemic patients, each harboring a heterozygous mutation (four de novo, two unphased) of SPI1, the gene encoding PU.1. Affected patients lacked circulating B cells and possessed few conventional dendritic cells. Introducing disease-similar SPI1 mutations into human hematopoietic stem and progenitor cells impaired early in vitro B cell and myeloid cell differentiation. Patient SPI1 mutations encoded destabilized PU.1 proteins unable to nuclear localize or bind target DNA. In PU.1-haploinsufficient pro–B cell lines, euchromatin was less accessible to nonpioneer TFs critical for B cell development, and gene expression patterns associated with the pro– to pre–B cell transition were undermined. Our findings molecularly describe a novel form of agammaglobulinemia and underscore PU.1’s critical, dose-dependent role as a hematopoietic euchromatin gatekeeper.

A diagnostic host response biosignature for COVID-19 from RNA profiling of nasal swabs and blood

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease-19 (COVID-19), has emerged as the cause of a global pandemic. We used RNA sequencing to analyze 286 nasopharyngeal (NP) swab and 53 whole-blood (WB) samples from 333 patients with COVID-19 and controls. Overall, a muted immune response was observed in COVID-19 relative to other infections (influenza, other seasonal coronaviruses, and bacterial sepsis), with paradoxical down-regulation of several key differentially expressed genes. Hospitalized patients and outpatients exhibited up-regulation of interferon-associated pathways, although heightened and more robust inflammatory responses were observed in hospitalized patients with more clinically severe illness. Two-layer machine learning-based host classifiers consisting of complete (>1000 genes), medium (<100), and small (<20) gene biomarker panels identified COVID-19 disease with 85.1-86.5% accuracy when benchmarked using an independent test set. SARS-CoV-2 infection has a distinct biosignature that differs between NP swabs and WB and can be leveraged for COVID-19 diagnosis.

Evaluation of SARS-CoV-2 serology assays reveals a range of test performance

Appropriate use and interpretation of serological tests for assessments of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure, infection and potential immunity require accurate data on assay performance. We conducted a head-to-head evaluation of ten point-of-care-style lateral flow assays (LFAs) and two laboratory-based enzyme-linked immunosorbent assays to detect anti-SARS-CoV-2 IgM and IgG antibodies in 5-d time intervals from symptom onset and studied the specificity of each assay in pre-coronavirus disease 2019 specimens. The percent of seropositive individuals increased with time, peaking in the latest time interval tested (>20 d after symptom onset). Test specificity ranged from 84.3% to 100.0% and was predominantly affected by variability in IgM results. LFA specificity could be increased by considering weak bands as negative, but this decreased detection of antibodies (sensitivity) in a subset of SARS-CoV-2 real-time PCR-positive cases. Our results underline the importance of seropositivity threshold determination and reader training for reliable LFA deployment. Although there was no standout serological assay, four tests achieved more than 80% positivity at later time points tested and more than 95% specificity.

SARS-CoV-2 seroprevalence and neutralizing activity in donor and patient blood

Given the limited availability of serological testing to date, the seroprevalence of SARS-CoV-2-specific antibodies in different populations has remained unclear. Here, we report very low SARS-CoV-2 seroprevalence in two San Francisco Bay Area populations. Seroreactivity was 0.26% in 387 hospitalized patients admitted for non-respiratory indications and 0.1% in 1,000 blood donors in early April 2020. We additionally describe the longitudinal dynamics of immunoglobulin-G (IgG), immunoglobulin-M (IgM), and in vitro neutralizing antibody titers in COVID-19 patients. The median time to seroconversion ranged from 10.3-11.0 days for these 3 assays. Neutralizing antibodies rose in tandem with immunoglobulin titers following symptom onset, and positive percent agreement between detection of IgG and neutralizing titers was >93%. These findings emphasize the importance of using highly accurate tests for surveillance studies in low-prevalence populations, and provide evidence that seroreactivity using SARS-CoV-2 anti-nucleocapsid protein IgG and anti-spike IgM assays are generally predictive of in vitro neutralizing capacity.

SARS-CoV-2 seroprevalence and neutralizing activity in donor and patient blood from the San Francisco Bay Area

We report very low SARS-CoV-2 seroprevalence in two San Francisco Bay Area populations. Seropositivity was 0.26% in 387 hospitalized patients admitted for non-respiratory indications and 0.1% in 1,000 blood donors. We additionally describe the longitudinal dynamics of immunoglobulin-G, immunoglobulin-M, and in vitro neutralizing antibody titers in COVID-19 patients. Neutralizing antibodies rise in tandem with immunoglobulin levels following symptom onset, exhibiting median time to seroconversion within one day of each other, and there is >93% positive percent agreement between detection of immunoglobulin-G and neutralizing titers.

Test performance evaluation of SARS-CoV-2 serological assays

Background:

Serological tests are crucial tools for assessments of SARS-CoV-2 exposure, infection and potential immunity. Their appropriate use and interpretation require accurate assay performance data.

Method:

We conducted an evaluation of 10 lateral flow assays (LFAs) and two ELISAs to detect anti-SARS-CoV-2 antibodies. The specimen set comprised 128 plasma or serum samples from 79 symptomatic SARS-CoV-2 RT-PCR-positive individuals; 108 pre-COVID-19 negative controls; and 52 recent samples from individuals who underwent respiratory viral testing but were not diagnosed with Coronavirus Disease 2019 (COVID-19). Samples were blinded and LFA results were interpreted by two independent readers, using a standardized intensity scoring system.

Results:

Among specimens from SARS-CoV-2 RT-PCR-positive individuals, the percent seropositive increased with time interval, peaking at 81.8–100.0% in samples taken >20 days after symptom onset. Test specificity ranged from 84.3–100.0% in pre-COVID-19 specimens. Specificity was higher when weak LFA bands were considered negative, but this decreased sensitivity. IgM detection was more variable than IgG, and detection was highest when IgM and IgG results were combined. Agreement between ELISAs and LFAs ranged from 75.7–94.8%. No consistent cross-reactivity was observed.

Conclusion:

Our evaluation showed heterogeneous assay performance. Reader training is key to reliable LFA performance, and can be tailored for survey goals. Informed use of serology will require evaluations covering the full spectrum of SARS-CoV-2 infections, from asymptomatic and mild infection to severe disease, and later convalescence. Well-designed studies to elucidate the mechanisms and serological correlates of protective immunity will be crucial to guide rational clinical and public health policies.

Pooled Knockin Targeting for Genome Engineering of Cellular Immunotherapies

Adoptive transfer of genetically modified immune cells holds great promise for cancer immunotherapy. CRISPR knockin targeting can improve cell therapies, but more high-throughput methods are needed to test which knockin gene constructs most potently enhance primary cell functions in vivo. We developed a widely adaptable technology to barcode and track targeted integrations of large non-viral DNA templates and applied it to perform pooled knockin screens in primary human T cells. Pooled knockin of dozens of unique barcoded templates into the T cell receptor (TCR)-locus revealed gene constructs that enhanced fitness in vitro and in vivo. We further developed pooled knockin sequencing (PoKI-seq), combining single-cell transcriptome analysis and pooled knockin screening to measure cell abundance and cell state ex vivo and in vivo. This platform nominated a novel transforming growth factor β (TGF-β) R2-41BB chimeric receptor that improved solid tumor clearance. Pooled knockin screening enables parallelized re-writing of endogenous genetic sequences to accelerate discovery of knockin programs for cell therapies.

Timed inhibition of CDC7 increases CRISPR-Cas9 mediated templated repair

Repair of double strand DNA breaks (DSBs) can result in gene disruption or gene modification via homology directed repair (HDR) from donor DNA. Altering cellular responses to DSBs may rebalance editing outcomes towards HDR and away from other repair outcomes. Here, we utilize a pooled CRISPR screen to define host cell involvement in HDR between a Cas9 DSB and a plasmid double stranded donor DNA (dsDonor). We find that the Fanconi Anemia (FA) pathway is required for dsDonor HDR and that other genes act to repress HDR. Small molecule inhibition of one of these repressors, CDC7, by XL413 and other inhibitors increases the efficiency of HDR by up to 3.5 fold in many contexts, including primary T cells. XL413 stimulates HDR during a reversible slowing of S-phase that is unexplored for Cas9-induced HDR. We anticipate that XL413 and other such rationally developed inhibitors will be useful tools for gene modification.

Polymer-stabilized Cas9 nanoparticles and modified repair templates increase genome editing efficiency

Versatile and precise genome modifications are needed to create a wider range of adoptive cellular therapies1-5. Here we report two improvements that increase the efficiency of CRISPR-Cas9-based genome editing in clinically relevant primary cell types. Truncated Cas9 target sequences (tCTSs) added at the ends of the homology-directed repair (HDR) template interact with Cas9 ribonucleoproteins (RNPs) to shuttle the template to the nucleus, enhancing HDR efficiency approximately two- to fourfold. Furthermore, stabilizing Cas9 RNPs into nanoparticles with polyglutamic acid further improves editing efficiency by approximately twofold, reduces toxicity, and enables lyophilized storage without loss of activity. Combining the two improvements increases gene targeting efficiency even at reduced HDR template doses, yielding approximately two to six times as many viable edited cells across multiple genomic loci in diverse cell types, such as bulk (CD3+) T cells, CD8+ T cells, CD4+ T cells, regulatory T cells (Tregs), γδ T cells, B cells, natural killer cells, and primary and induced pluripotent stem cell-derived6 hematopoietic stem progenitor cells (HSPCs).

Regulatory T cells use arginase 2 to enhance their metabolic fitness in tissues

Distinct subsets of Tregs reside in nonlymphoid tissues where they mediate unique functions. To interrogate the biology of tissue Tregs in human health and disease, we phenotypically and functionally compared healthy skin Tregs with those in peripheral blood, inflamed psoriatic skin, and metastatic melanoma. The mitochondrial enzyme, arginase 2 (ARG2), was preferentially expressed in Tregs in healthy skin, increased in Tregs in metastatic melanoma, and reduced in Tregs from psoriatic skin. ARG2 enhanced Treg suppressive capacity in vitro and conferred a selective advantage for accumulation in inflamed tissues in vivo. CRISPR-mediated deletion of this gene in primary human Tregs was sufficient to skew away from a tissue Treg transcriptional signature. Notably, the inhibition of ARG2 increased mTOR signaling, whereas the overexpression of this enzyme suppressed it. Taken together, our results suggest that Tregs express ARG2 in human tissues to both regulate inflammation and enhance their metabolic fitness.

Dirofilariasis in Vietnam: A case report and brief review

This report describes a rare case of ophthalmic dirofilariasis in a 68-year-old woman with red and foreign body sensation in the pterygium on her right eye. Slit lamp examination demonstrated a long-slender worm moving in her pterygium. The worm was removed surgically and then identified as Diroflaria repens by sequence analysis of the small subunit ribosomal RNA (SSU) gene. The situation of dirofilariasis in Vietnam has been reviewed. Since the first described case in 2010 there have been thirteen cases reported that suggested the emerging trend of the disease. Most of the documented cases of human dirofilariasis recorded in Vietnam presented with ocular infections and the responsible agent was D. repens. With the increase of reported cases of human, much more attention should be paid on control as well as diagnosis and treatment of dirofilariasis in Vietnam.

Pulsed-coil magnet systems for applying uniform 10-30 T fields to centimeter-scale targets on Sandia's Z facility

Sandia has successfully integrated the capability to apply uniform, high magnetic fields (10-30 T) to high energy density experiments on the Z facility. This system uses an 8-mF, 15-kV capacitor bank to drive large-bore (5 cm diameter), high-inductance (1-3 mH) multi-turn, multi-layer electromagnets that slowly magnetize the conductive targets used on Z over several milliseconds (time to peak field of 2-7 ms). This system was commissioned in February 2013 and has been used successfully to magnetize more than 30 experiments up to 10 T that have produced exciting and surprising physics results. These experiments used split-magnet topologies to maintain diagnostic lines of sight to the target. We describe the design, integration, and operation of the pulsed coil system into the challenging and harsh environment of the Z Machine. We also describe our plans and designs for achieving fields up to 20 T with a reduced-gap split-magnet configuration, and up to 30 T with a solid magnet configuration in pursuit of the Magnetized Liner Inertial Fusion concept.

Small-Molecule End-Groups of Linear Polymer Determine Cell-type Gene-Delivery Efficacy

End-modified polymers are promising for the nonviral delivery of genes to cancer cells, immune cells, and human stem cells and point to polymer end-groups as regulators for cell-type specificity. A library of polymers has been synthesized and, although some polymers are strong transfection agents overall, for each cell type, a particular polymer is most effective.

A novel high-throughput cell-based method for integrated quantification of type I interferons and in vitro screening of immunostimulatory RNA drug delivery

A hallmark of immune activation by certain RNA sequences is the generation of interferon responses. However, the study of immunostimulatory RNA (isRNA) has been hindered by costly and slow methods, particularly in vitro. We have developed a cell-based assay to detect human type I interferon (IFN) that reliably senses both IFN-alpha and IFN-beta simultaneously. The human 293T cell line was stably transfected with a fusion gene of monomeric red fluorescent protein (mRFP) under the transcriptional control of an interferon-stimulated response element (ISRE). High levels of mRFP are expressed following activation of the type I IFN receptor (IFNAR). Using this method, detection limits for IFN similar to that of ELISA can be achieved but with a greater dynamic range and in a high-throughput manner. As a proof of concept, we utilized this method to screen a library of cationic lipid-like materials that form nanoparticle complexes with RNA for induction of innate immune responses in vitro. We expect the screening and detection methods described herein may provide a useful tool in elucidating mechanisms that govern the delivery of RNA molecules to effector cells and receptors of the innate immune system. We apply this tool to investigate isRNA drug delivery, but it may also find use in other applications for which high-throughput detection of type 1 IFN is desired.

Polymeric Materials for Gene Delivery and DNA Vaccination

Gene delivery holds great potential for the treatment of many different diseases. Vaccination with DNA holds particular promise, and may provide a solution to many technical challenges that hinder traditional vaccine systems including rapid development and production and induction of robust cell-mediated immune responses. However, few candidate DNA vaccines have progressed past preclinical development and none have been approved for human use. This Review focuses on the recent progress and challenges facing materials design for nonviral DNA vaccine drug delivery systems. In particular, we highlight work on new polymeric materials and their effects on protective immune activation, gene delivery, and current efforts to optimize polymeric delivery systems for DNA vaccination.

Enhancement of poly(orthoester) microspheres for DNA vaccine delivery by blending with poly(ethylenimine)

Poly(orthoester) (POE) microspheres have been previously shown to possess certain advantages for the in vivo delivery of DNA vaccines. In particular, timing of DNA release from POE microspheres in response to acidic phagosomal pH was shown to be an important factor in determining immunogenicity, which was hypothesized to be linked to the natural progression of antigen-presenting cell uptake, transfection, maturation, and antigen presentation. Here we report in vitro characterization of the enhanced efficacy of POE microspheres by blending poly(ethylenimine) (PEI), a well-characterized cationic transfection agent, into the POE matrix. Blending of a tiny amount of PEI (approximately 0.04 wt%) with POE caused large alterations in POE microsphere properties. PEI provided greater control over the rate of pH-triggered DNA release by doubling the total release time of plasmid DNA and enhanced gene transfection efficiency of the microspheres up to 50-fold without any significant cytotoxicity. Confocal microscopy results of labeled PEI and DNA plasmids revealed that PEI caused a surface-localizing distribution of DNA and PEI within the POE microsphere as well as focal co-localization of PEI with DNA. We provide evidence that upon degradation, the microspheres of POE-PEI blends released electrostatic complexes of DNA and PEI, which are responsible for the enhanced gene transfection. Furthermore, blending PEI into the POE microsphere induced 50-60% greater phenotypic maturation and activation of bone marrow-derived dendritic cells in vitro, judged by the up-regulation of co-stimulatory markers on the cell surface. Physically blending PEI with POE is a simple approach for modulating the properties of biodegradable microspheres in terms of gene transfection efficiency and DNA release kinetics. Combined with the ability to induce maturation of antigen-presenting cells, POE-PEI blended microspheres may be excellent carriers for DNA vaccines.

Enhancement of poly(orthoester) microspheres for DNA vaccine delivery by blending with poly(ethylenimine)

Poly(orthoester) (POE) microspheres have been previously shown to possess certain advantages for the in vivo delivery of DNA vaccines. In particular, timing of DNA release from POE microspheres in response to acidic phagosomal pH was shown to be an important factor in determining immunogenicity, which was hypothesized to be linked to the natural progression of antigen-presenting cell uptake, transfection, maturation, and antigen presentation. Here we report in vitro characterization of the enhanced efficacy of POE microspheres by blending poly(ethylenimine) (PEI), a well-characterized cationic transfection agent, into the POE matrix. Blending of a tiny amount of PEI (approximately 0.04 wt%) with POE caused large alterations in POE microsphere properties. PEI provided greater control over the rate of pH-triggered DNA release by doubling the total release time of plasmid DNA and enhanced gene transfection efficiency of the microspheres up to 50-fold without any significant cytotoxicity. Confocal microscopy results of labeled PEI and DNA plasmids revealed that PEI caused a surface-localizing distribution of DNA and PEI within the POE microsphere as well as focal co-localization of PEI with DNA. We provide evidence that upon degradation, the microspheres of POE-PEI blends released electrostatic complexes of DNA and PEI, which are responsible for the enhanced gene transfection. Furthermore, blending PEI into the POE microsphere induced 50-60% greater phenotypic maturation and activation of bone marrow-derived dendritic cells in vitro, judged by the up-regulation of co-stimulatory markers on the cell surface. Physically blending PEI with POE is a simple approach for modulating the properties of biodegradable microspheres in terms of gene transfection efficiency and DNA release kinetics. Combined with the ability to induce maturation of antigen-presenting cells, POE-PEI blended microspheres may be excellent carriers for DNA vaccines.

What does Chilean research tell us about postpartum depression (PPD)?

BACKGROUND

In Chile, a country with a so called emerging market-economy, where rapid social and life style changes are taking place, women and the more socially disadvantaged are more at risk of becoming depressed.

METHODS

Results of several studies are summarized in the context of a review of the literature.

RESULTS

A third of Chilean women have depressive and/or anxiety symptoms during midpregnancy, while prevalence figures both in the early and the late postpartum period increase up to 50% in most studies. If strict operational criteria describing well defined depressive disorders are used postnatally, differences in prevalence and incidence figures arise depending on socioeconomic status. Whereas incidence rates for postpartum depression (around 9%) are very similar to those found in the northern hemisphere and do not appear to vary across different socioeconomic levels, higher prevalence rates are found among women from lower socioeconomic status.

LIMITATIONS

The studies focused on current diagnostic entities and did not consider different clusters or dimensions.

CONCLUSION

A shared biological etiology may be triggered by the physiology of childbirth and account for similarities in incidence across different socioeconomic levels. In turn, we hypothesize that the higher prevalence of postpartum depression (PPD) in Chilean women from lower socioeconomic status is the result of pre-existing depression and is not caused by more new cases of the illness.

The Drosophila homolog of Onecut homeodomain proteins is a neural-specific transcriptional activator with a potential role in regulating neural differentiation

We report here the characterization of the Drosophila homolog of the onecut homeobox gene, which encodes a protein product with one cut domain and one homeodomain. We present evidence that D-Onecut can bind to similar DNA sequences with high specificity and affinity as other Onecut proteins through the highly conserved cut domain and homeodomain. Interestingly, the cut domain alone can mediate DNA-binding, but the homeodomain cannot. However, depending upon the promoter context, we observed cooperative interactions between the two domains to confer high DNA-binding affinity and specificity. D-Onecut appears to be a moderate transcriptional activator and functions as a nuclear protein in neuronal tissues of both the CNS and PNS during development and in the adult. In the eye, D-Onecut expression is independent of glass, a transcriptional regulator of R cell differentiation. Taken together, our results suggest a role for D-Onecut in the regulation of some aspects of neural differentiation or maintenance. In support of this notion, overexpression of a putative dominant negative form of D-Onecut during eye development does not affect early cell fate specification, but severely affects photoreceptor differentiation.

Cardiac troponins I and T are biological markers of left ventricular dysfunction in septic shock

BACKGROUND

Cardiac depression in severe sepsis and septic shock is characterized by left ventricular (LV) failure. To date, it is unclear whether clinically unrecognized myocardial cell injury accompanies, causes, or results from this decreased cardiac performance. We therefore studied the relationship between cardiac troponin I (cTnI) and T (cTnT) and LV dysfunction in early septic shock.

METHODS

Forty-six patients were consecutively enrolled, fluid-resuscitated, and treated with catecholamines. Cardiac markers were measured at study entry and after 24 and 48 h. LV function was assessed by two-dimensional transesophageal echocardiography.

RESULTS

Increased plasma concentrations of cTnI (>/=0.4 microgram/L) and cTnT (>/=0.1 microgram/L) were found in 50% and 36%, respectively, of the patients at one or more time points. cTnI and cTnT were significantly correlated (r = 0.847; P <0.0001). Compared with cTnI-negative patients, cTnI-positive subjects were older, presented higher Acute Physiology and Chronic Health Evaluation II scores at diagnosis, and tended to have a worse survival rate and a more frequent history of arterial hypertension or previous myocardial infarction. In contrast, the two groups did not differ in type of infection or pathogen, or in dose and type of catecholamine administered. Continuous electrocardiographic monitoring in all patients and autopsy in 12 nonsurvivors did not disclose the occurrence of acute ischemia during the first 48 h of observation. LV dysfunction was strongly associated with cTnI positivity (78% vs 9% in cTnI-negative patients; P <0.001). In multiple regression analysis, both cTnI and cTnT were exclusively associated with LV dysfunction (P <0.0001).

CONCLUSIONS

These findings suggest that in septic shock, clinically unrecognized myocardial cell injury is a marker of LV dysfunction. The latter condition tends to occur more often in severely ill older patients with underlying cardiovascular disease. Further studies are needed to determine the extent to which myocardial damage is a cause or a consequence of LV dysfunction.

Liver perfusion and hepatocellular inflammatory response in sepsis

Sepsis is characterized by disturbances in liver perfusion and alterations in intrahepatic cellular functions and interactions. This provokes structural and functional liver damage as well as hepatocellular activation that is believed to perpetuate the immuno-inflammatory response. Changes in hepatic perfusion during sepsis are still poorly understood due to the heterogeneity of septic animal models and the difficult accessibility of the hepatic circulation in humans. Sinusoidal blood flow is severely compromised during sepsis due to a decline in perfused sinusoidal area in association with a decrease in sinusoidal flow velocity. Imbalances in the production of nitric oxide may account for these (micro) circulatory disorders. Interactions between liver macrophages, activated endothelial cells and hepatocytes determine the intensity of inflammation and contribute to initial liver damage. Hepatocellular injury is then enhanced by attracted and invading neutrophils. The management of hepatic dysfunction during sepsis is largely supportive and based on prevention and vigorous resuscitation including early nutritional support and adequate oxygenation. Interestingly, experimental studies suggest that pharmacological interventions with significant hemodynamic effects, such as dobutamine and nitric oxide synthase inhibitors, may adversely affect the liver during the septic process.

The sidekick gene, a member of the immunoglobulin superfamily, is required for pattern formation in the Drosophila eye

In the Drosophila eye imaginal disc the photoreceptor cells (R cells) differentiate according to a precise spatial and temporal order. The sidekick (sdk) gene is necessary to prevent extra R cells from differentiating during eye disc development. The extra cell appears between R3 and R4 early in R cell clusters and is most likely the result of the mystery cell inappropriately differentiating as an R cell. Mosaic analysis shows that sdk is required neither in the R cells nor in the extra cell, suggesting that sdk is necessary in the surrounding undifferentiated cells. The sdk gene codes for a protein that is a member of the immunoglobulin superfamily, having six immunoglobulin domains, thirteen fibronectin repeats and a transmembrane domain. The protein structure is consistent with its participation in cell-cell interaction during eye development.

Isolation and measurement of the endogenous cannabinoid receptor agonist, anandamide, in brain and peripheral tissues of human and rat

Anandamide (arachidonylethanolamide) is a novel lipid neurotransmitter first isolated from porcine brain which has been shown to be a functional agonist for the cannabinoid CB1 and CB2 receptors. Anandamide has never been isolated from human brain or peripheral tissues and its role in human physiology has not been examined. Anandamide was measured by LC/MS/MS and was found in human and rat hippocampus (and human parahippocampal cortex), striatum, and cerebellum, brain areas known to express high levels of CB1 cannabinoid receptors. Significant levels of anandamide were also found in the thalamus which expresses low levels of CB1 receptors. Anandamide was also found in human and rat spleen which expresses high levels of the CB2 cannabinoid receptor. Small amounts of anandamide were also detected in human heart and rat skin. Only trace quantities were detected in pooled human serum, plasma, and CSF. The distribution of anandamide in human brain and spleen supports its potential role as an endogenous agonist in central and peripheral tissues. The low levels found in serum, plasma, and CSF suggest that it is metabolized in tissues where it is synthesized, and that its action is probably not hormonal in nature.

Sodium nitroprusside does not influence tissue oxygen extraction capabilities during a critical reduction in oxygen delivery

By its regulating effects on blood vessel tone, nitric oxide (NO) may play an important role in the coupling of oxygen delivery (DO2) to metabolic rate. We reasoned that if endogenous NO synthesis is an important modulator of oxygen extraction ratio (O2ER), then administration of a NO donor will alter oxygen extraction capabilities during a fall in blood flow. We studied the effects of the NO donor, nitroprusside, on the relationship between DO2 and oxygen uptake (VO2) during an acute reduction in DO2 induced by cardiac tamponade. Twenty-one healthy, anaesthetised, mechanically ventilated dogs were randomly divided into 3 groups. Group 1 (n = 7) served as control; Groups 2 and 3 were given sodium nitroprusside at 1.0 microgram/kg.min (n = 7), and 2.5 micrograms/kg.min intravenously (n = 7), respectively. All animals were given normal saline i.v. at a rate of 20 ml/kg.h throughout the study. Cardiac tamponade was induced by bolus injections of normal saline into the pericardial space. In the control animals the critical DO2 (DO2crit) was found at 10.1 +/- 1.5 ml/kg.min and critical O2ER (O2ERcrit) at 63.3 +/- 10.9%. Nitroprusside at the lower dose decreased systemic vascular resistance but did not significantly influence arterial pressure, cardiac output, DO2 or VO2; neither DO2crit nor O2ERcrit was altered (9.3 +/- 2.9 ml/kg.min and 70.4 +/- 20.9%). Nitroprusside at the higher dose induced significant decreases in mean arterial pressure and systemic vascular resistance, but had no significant effect on cardiac output. DO2crit (9.2 +/- 2.0 ml/kg.min) and O2ERcrit (59.8 +/- 13.2%) were similar to the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Protein mass spectrometry: applications to analytical biotechnology

The advent of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and electrospray ionization mass spectrometry (ESI-MS) in the last 5 years has greatly enhanced the area of protein mass spectrometry. This paper presents an overview of the applications of protein mass spectrometry in the area of analytical biotechnology, particularly as related to biopharmaceutical research and development. These applications include the determination of protein molecular mass, peptide mapping, peptide sequencing, ligand binding, determination of disulfide bonds, active site characterization of enzymes, protein self-association and protein folding/higher order structural characterization.

Effects of N-acetyl-L-cysteine on regional blood flow during endotoxic shock

We previously reported that N-acetyl-L-cysteine (NAC), an oxygen free-radical scavenger, can increase the oxygen extraction capabilities during endotoxic shock when blood flow is progressively reduced. In the present study, we investigated whether the protective effects of NAC are related to an improvement in regional blood flow following endotoxemia. Fourteen anesthetized, saline-infused and ventilated dogs were divided into two groups: 7 dogs received NAC (150 mg/kg, followed by a 20 mg/kg.h infusion), and the other 7 dogs served as a control time-matching group. Thirty minutes later all the dogs received Escherichia coli endotoxin (2 mg/kg) i.v. A saline infusion was started 30 min after endotoxin challenge to restore pulmonary artery occlusion pressure to baseline and maintain it constant. Regional blood flow was measured by ultrasonic volume flowmeter. In the control group, arterial pressure, left ventricular stroke work index and systemic vascular resistance remained lower than baseline. Mesenteric, renal and femoral arterial blood flow increased but only femoral blood flow returned to baseline levels. In the NAC group, cardiac index and left ventricular stroke work index remained higher and systemic and pulmonary vascular resistance were lower than in the control group. Blood flow in mesenteric, renal and especially femoral arteries was higher than in the control group. Fractional blood flow increased only in the femoral artery. PaO2 and PvO2 had similar courses in the two groups. A higher venous admixture was associated with a higher cardiac index and a lower pulmonary vascular resistance in the NAC group. Oxygen delivery and oxygen-uptake were higher in the NAC-treated than in the control animals throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Prostaglandin E1 increases oxygen extraction capabilities in experimental sepsis

By its microvascular and anti-inflammatory actions, prostaglandin E1 (PGE1) has been suggested both in animal models and in humans to have a therapeutic value in sepsis. To investigate whether PGE1 could improve the oxygen extraction capabilities in severe sepsis, our study focused on the relationship between oxygen uptake (VO2) and oxygen delivery (DO2) during an acute reduction in blood flow induced by cardiac tamponade in endotoxic dogs. Thirty anesthetized, ventilated dogs were divided into three groups. A first group (N = 10) served as a control receiving 20 ml/kg/hr of saline intravenously. A second group (N = 10) received PGE1 at 100 ng/kg/min along with the same saline infusion. A third group (N = 10) received the same dose of PGE1 with only 1 ml/kg/hr of saline. Thirty minutes after the initiation of this therapy, Escherichia coli endotoxin (2 mg/kg) was injected in each dog. In each group, the administration of PGE1, fluids, or both was continued throughout the study. Tamponade was then induced by repeated bolus injections of warm saline into the pericardial space. Steady-state measurements of VO2 (derived from the expired gases) and DO2 (the product of cardiac index and oxygen content) were obtained sequentially after each saline injection. The administration of PGE1 + fluids resulted in significant increases in stroke volume, cardiac index, and DO2 and reductions in systemic and pulmonary vascular resistance. Stroke volume and cardiac index were lower in the PGE1 alone than in the PGE1 + fluids group. The VO2 levels at critical DO2 (DO2crit) were identical. However, DO2crit, which was 12.2 +/- 2.8 ml/kg/min in the control group, was significantly decreased to 9.8 +/- 2.0 ml/kg/min in the PGE1 + fluids and to 9.3 +/- 2.7 ml/kg/min in the PGE1 alone group (both P < 0.05). Critical oxygen extraction ratio (O2ERcrit) which was 47 +/- 14% in the control group, was increased to 63 +/- 16% in the PGE1 + fluids group and to 61 +/- 17% in the PGE1 alone group (both P < 0.05). To investigate whether PGE1 also improves oxygen extraction capabilities in the absence of endotoxin, a second series of experiments was performed in 14 dogs, receiving saline alone (Control, N = 7) or plus PGE1 at 100 ng/kg/min (PGE1, N = 7). DO2crit was 10.7 +/- 2.9 ml/kg/min in the PGE1 group vs 10.1 +/- 1.8 ml/kg/min in the control group (NS). O2ERcrit tended to be higher in the PGE1 group than that in the control group (68 +/- 13% vs 60 +/- 15%, P = 0.054).(ABSTRACT TRUNCATED AT 400 WORDS)

Pentoxifylline improves the tissue oxygen extraction capabilities during endotoxic shock

Pentoxifylline (PTX), a xanthine derivative used in the treatment of circulatory insufficiency, has been found to have protective effects in different models of sepsis. We hypothesized that this drug might improve the cellular oxygen availability following endotoxin challenge by increasing oxygen delivery (DO2) and/or tissue oxygen extraction. The oxygen extraction capabilities were studied during a reduction in blood flow induced by cardiac tamponade. Fourteen anesthetized, ventilated, and paralyzed dogs, received intravenous 2 mg/kg of Escherichia coli endotoxin followed by a continuous infusion of 20 ml/kg.h of saline. 30 min later tamponade was induced by repeated bolus injections of warm saline into the pericardial space. Seven dogs were pretreated with PTX as an intravenous bolus of 20 mg/kg, followed by a continuous infusion at 20 mg/kg.h, and the other seven dogs served as a control group. PTX largely attenuated the systemic and pulmonary vasoconstriction observed in the control group and resulted in significant increases in cardiac index, DO2 and oxygen consumption (VO2). PTX also improved ventilation/perfusion matching in the lungs as indicated by a higher PaO2 and PvO2 and a lower venous admixture than in the untreated group during cardiac tamponade (both p < .05). In addition, the critical DO2 (DO2 crit) was lower and the critical oxygen extraction ratio was higher in the PTX treated than in the control group (9.1 +/- 1.8 vs. 11.6 +/- 2.4 ml/kg.min, and 70.6 +/- 14.0 vs. 49.3 +/- 14.6%, both p < .05). The VO2/DO2 dependency slope was also steeper in the PTX-treated than in the control group (.80 +/- .28 vs. .43 +/- .19, p < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Protective effects of N-acetyl-L-cysteine in endotoxemia

Because oxygen free radicals have been implicated in the endothelial cell damage and in the myocardial depression occurring during severe sepsis, we investigated whether N-acetyl-L-cysteine (NAC) could influence the oxygen extraction capabilities during an acute reduction in blood flow induced by cardiac tamponade after endotoxin challenge. Sixteen anesthetized, saline-infused, and ventilated dogs received Escherichia coli endotoxin (2 mg/kg) 30 min before tamponade was induced by repeated bolus injections of warm saline into the pericardial space. Thirty minutes before endotoxin administration, nine dogs received NAC (150 mg/kg, followed by a 20 mg.kg-1.h-1 infusion); the other seven dogs served as a control group. The NAC group maintained higher cardiac index, oxygen delivery (DO2), and left ventricular stroke work index, but lower systemic and pulmonary vascular resistance, than the control group. The oxygen uptake (VO2) levels at critical DO2 (DO2crit) were identical in the two groups. However, DO2crit was significantly lower in the NAC than in the control group (8.1 +/- 1.7 vs. 10.8 +/- 1.8 ml.kg-1.min-1, P < 0.01). Critical oxygen extraction ratio and the slope of the VO2-to-DO2-dependent line were higher in the NAC than in the control group (72 +/- 14 vs. 53 +/- 15% and 0.80 vs. 0.56, respectively; both P < 0.05). The peak lactate and the maximal tumor necrosis factor (TNF) levels were lower in the NAC than in the control group (5.2 +/- 0.4 vs. 7.6 +/- 0.4 mM, and 0.14 +/- 0.03 vs. 1.21 +/- 0.58 ng/ml, respectively; both P < 0.01). NAC significantly increased glutathione peroxidase activity.(ABSTRACT TRUNCATED AT 250 WORDS)

The stimulatory and inhibitory effects of dopamine on prolactin secretion involve different G-proteins

The reverse hemolytic plaque assay (RHPA) was used in this study to further characterize the mechanism whereby low concentrations of dopamine (DA) stimulate PRL secretion in vitro. Female Sprague-Dawley rats were used as a source of anterior pituitary cells for the RHPA. Pituitary cells were infused into Cunningham chambers along with a suspension of protein-A-coated ovine red blood cells. Excess cells were rinsed from the chambers leaving a monolayer of cells attached to the glass. The cells were then incubated with solutions containing PRL antiserum (1:40) and various concentrations of DA. After 4 h, a solution containing guinea pig complement (1:60) was infused into the chambers. Thirty minutes later, the cells were fixed and plaques (zones of hemolysis) surrounding PRL-producing cells (lactotrophs) were measured and used as an index of the amount of PRL secreted. Control cells that received no DA had a mean plaque area of 8,000 microns 2 and two distinct subpopulations of plaque sizes. This biphasic population of cells consisted of a small and a large plaque producing population. The mean plaque area surrounding lactotrophs was significantly (P less than 0.05) decreased if 1 microM or 10 microM DA was present (4,500 microns 2 and 3,500 microns 2, respectively). These cells which received inhibitory concentrations of DA demonstrated a monophasic distribution of plaque-forming cells. On the other hand, mean plaque area was significantly (P less than 0.05) increased if 0.1 nM or 1 nM DA was presented to the cells (15,000 microns 2 and 14,500 microns 2, respectively). These cells receiving stimulatory doses of DA exhibited a multiphasic distribution of plaque-forming cells. The possibility that the two physiological opposing actions of DA on PRL secretion might be mediated by different GTP binding proteins was also examined using cholera toxin (CTX) and pertussis toxin (PTX). Anterior pituitary cells were pretreated with either CTX (50 micrograms/ml) or PTX (5 micrograms/ml) for 1 h before initiation of the RHPA. In the RHPA, cells received no DA, a stimulatory dose of DA (0.1 nM), or a inhibitory dose of DA (10 microM). The effects of toxin pretreatment on mean plaque area of DA-treated cells was determined. PTX pretreatment significantly attenuated the inhibitory effects of DA while having no effect on the stimulatory effects of DA on PRL secretion. CTX significantly (P less than 0.05) potentiated the stimulatory effects of DA on PRL secretion and had no effect on inhibition.(ABSTRACT TRUNCATED AT 400 WORDS)

Hysterectomy-induced alterations in prolactin secretion of lactating rats

The contribution of the uterus to the regulation of PRL secretion in lactating dams and cycling female rats was investigated. Lactating animals were hysterectomized or sham operated 2 days after parturition, and the number of pups was adjusted to eight. Blood samples for PRL RIA were obtained through intra-atrial cannulae implanted 2 days before experimentation. In order to study the PRL secretory profile in undisturbed freely lactating rats, blood samples were taken every 2 h for 24 h starting at 1400 h. During early lactation (days 7-8), hysterectomy did not alter the PRL secretory profile compared to that of sham-operated controls. On days 14-15 post partum, PRL secretion followed a characteristic bimodal pattern showing two PRL surges at 1800 h and 0600 h. After hysterectomy, the early morning PRL surge disappeared and PRL secretion showed an unimodal daily rhythm reaching its peak at 1800 h. The possible effect of the absence of the uterus on suckling-induced PRL release at various stages of lactation was studied. On days 7-8, suckling stimuli after 4 h of pup deprivation induced robust PRL release. Hysterectomy did not significantly alter PRL release at this earlier stage of lactation. In control groups, the suckling-induced PRL secretory response markedly declined as the postpartum period advanced. On the other hand, the hysterectomized animals retained significantly greater responsiveness to suckling during the second half of lactation. These data indicate an inhibitory influence of the uterus on PRL secretion. The onset of this uterine effect is considerably delayed, and its influence became prominent only at a later phase of lactation. The effect of length of pup deprivation preceding the suckling stimulus, in combination with hysterectomy, was also investigated. Hysterectomy significantly increased suckling-induced PRL release after 4 and 24 h separation compared to the sham-hysterectomized animals. When the separation was longer than 48 h, the inducibility of PRL release by suckling declined and was not influenced by hysterectomy. In order to study the possible influence of the uterus on PRL secretion during the estrous cycle, regularly cycling female rats were hysterectomized at diestrus 1. Twelve days later the animals were cannulated, and serial blood samples were taken during the subsequent proestrus. Hysterectomy did not alter the PRL surge which occurred on the afternoon of proestrus indicating that the uterus does not have a major function in regulating PRL secretion on proestrus. In conclusion, hysterectomy significantly delayed the extinction of suckling-induced PRL release revealing the active role of the uterus in the regulation of this neuroendocrine reflex.