Validation of the brain injury associated visual impairment - impact questionnaire (BIVI-IQ).

PURPOSE: The Brain Injury associated Visual Impairment - Impact Questionnaire (BIVI-IQ) was developed to assess the impact of post-stroke visual impairment. The development of the questionnaire used robust methods involving stroke survivors and clinicians. The aim of this study was to assess the validity of the BIVI-IQ in a stroke population. METHODS: Stroke survivors with visual impairment were recruited from stroke units, outpatient clinics and non-healthcare settings. Participants were asked to complete questionnaire sets on three separate occasions; the BIVI-IQ at each visit with additional questionnaires at baseline and visit 2. Vision assessment and anchor questions from participants and clinicians were collected. The analysis included assessment of missing data, acceptability, Rasch model analysis, test-retest reliability, construct validity (NEI VFQ-25, EQ-5D-5L) and responsiveness to change. RESULTS: 316 stroke survivors completed at least one questionnaire of the 326 recruited. Mean age was 67 years and 64% were male. Adequate fit statistics to the Rasch model were reached (χ2 = 73.12, p = 0.02) with two items removed and thresholds of two adjusted, indicating validity and unidimensionality. Excellent test-retest reliability was demonstrated (ICC = 0.905) with a 3-month interval. Construct validity was demonstrated with a strong significant correlation to the NEI VFQ-25 (r = 0.837, p < 0.01). The BIVI-IQ also demonstrated responsiveness to change with significant differences identified between groups based on participant and clinician anchor questions (X2 = 23.29, p < 0.001; X2 = 24.56, p < 0.001). CONCLUSION: The BIVI-IQ has been shown to be valid and practical for 'everyday' use by clinicians and researchers to monitor vision-related quality of life in stroke survivors with visual impairment.

Milk triglycerides from dairy cows abomasally infused with increasing amounts of high-oleic sunflower fatty acids.

The triglyceride composition of milk fat largely determines the manufacturing characteristics of products containing milk fat. Increasing oleic acid content of milk fat might be desirable for human nutrition and also for butter and whipping cream, among other product applications. The objective of this research was to determine the effects of increasing intestinally available oleic acid (provided via abomasal infusion) on the profile of milk triglycerides. A control and 4 increasing doses of free fatty acids from high oleic sunflower oil (HOSFA) were infused into the abomasum of 4 lactating dairy cows in a changeover experimental design with periods of 7 d. Treatments were (1) control (no fatty acids infused), (2) HOSFA (250 g/d), (3) HOSFA (500 g/d), (4) HOSFA (750 g/d), and (5) HOSFA (1,000 g/d). All treatments included meat solubles and Tween 80 as emulsifiers. Infusion of HOSFA increased oleic acid and decreased short- and medium-chain fatty acids in milk fat. Statistical analysis of results showed linear changes in most of the milk triglycerides analyzed. The most significant changes as the result of increasing HOSFA infusion were a decrease in triglycerides with saturated fatty acids (butyrin-caprylin-palmitin, butyrin-laurin-olein, butyrin-myristin-palmitin, butyrin-palmitin-palmitin, caproin-myristin-palmitin, butyrin-palmitin-stearin, caproin-palmitin-palmitin) and an increase in dioleyl triglycerides (with butyric, lauric, myristic and palmitic acids) and triolein. The synthesis of triglyceride is position-specific and does not follow a random distribution model.

Difficult airway management algorithms: a directed review.

The primary aim of this study was to identify, describe and compare the content of existing difficult airway management algorithms. Secondly, we aimed to describe the literature reporting the implementation of these algorithms. A directed search across three databases (MEDLINE, Embase and Scopus) was performed. All articles were screened for relevance to the research aims and according to pre-determined exclusion criteria. We identified 38 published airway management algorithms. Our results show that most facemask employ a four-step process as represented by a flow chart, with progression from tracheal intubation, facemask ventilation and supraglottic airway device use, to a rescue emergency surgical airway. The identified algorithms are overwhelmingly similar, yet many use differing terminology. The frequency of algorithm publication has increased recently, yet adherence and implementation outcome data remain limited. Our results highlight the lack of a single algorithm that is universally endorsed, recognised and applicable to all difficult airway management situations.

'It's something you have to put up with'--service users' experiences of in utero transfer: a qualitative study.

OBJECTIVE: The purpose of this study was to gain in-depth insight and enhance understanding of service users' experiences of the in utero transfer (IUT) process, in order to inform policy and improve the current service provision of maternal care. DESIGN: Qualitative descriptive study using semi-structured interviews. SETTING: Participant's home or hospital in the Midlands, UK. POPULATION: Fifteen women transferred in utero to a tertiary level maternity hospital; five male partners and two grandmothers. METHODS: Audio-recorded individual or paired semi-structured interviews transcribed verbatum and analysed thematically using nvivo 9. MAIN OUTCOME MEASURES: Facilitators and barriers of the IUT experience. RESULTS: Findings suggest that IUT is an emotional experience that financially disadvantages patients and their families. Male partners were perceived to be most negatively affected by the experience. The quality of the IUT experience was influenced by a range of factors, including the lack of proximity to home and the lack of information. Patients had little knowledge or awareness of IUT, and most felt unprepared for displacement. Despite this, there was resigned acceptance that IUT was a necessary rather than adverse experience. CONCLUSIONS: The experience of IUT for service users could be enhanced by ensuring that they are better informed about the process and the circumstances that necessitate displacement, that they are better informed about the hospital to which they are being transferred, and that they are transferred as close to home as possible. Efforts to minimise the emotional and socio-economic impact of IUT on women and their families also need to be considered.

The impact of prostate cancer on men's everyday life.

Prostate cancer impacts on the daily lives of men, particularly their physical and emotional health, relationships and social life. This paper highlights how men cope with disease and treatment and the strategies they employ to manage their diagnosis alongside daily life. Twenty-seven men were interviewed at different stages in their disease pathway: nine men prior to radiotherapy, eight men at 6-8 months post radiotherapy and 10 men at 12-18 months post radiotherapy. A grounded theory approach was used to collect and analyse the data. Regardless of the point at which they were interviewed four areas emerged as important to the men: the pathway to diagnosis; the diagnosis; the impact of prostate cancer and its treatment on daily life; and living with prostate cancer. Prostate cancer was diagnosed using the prostate-specific antigen (PSA) test, rectal examination and biopsy. Many men did not understand the consequences of a high PSA reading before they undertook the test. Painful investigative biopsies were viewed as the worst part of the disease experience. Radiotherapy was considered less invasive than other treatments, although preparatory regimes were associated with stress and inconvenience. Men used various strategies to deal with treatment-induced threats to their masculinity in the long term.

Objective Linguistic Markers Associated with Callous-Unemotional Traits in Early Childhood.

BACKGROUND: Callous-unemotional (CU) traits are associated with interpersonal difficulties and risk for severe conduct problems (CP). The ability to communicate thoughts and feelings is critical to social success, with language a promising treatment target. However, no prior studies have examined objective linguistic correlates of childhood CU traits in early childhood, which could give insight into underlying risk mechanisms and novel target treatments. METHODS: We computed lexical (positive emotion, sad, and anger words) and conversational (interruptions and speech rate) markers produced by 131 children aged 5-6 years (M = 5.98; SD = 0.54, 58.8% female) and their parents while narrating wordless storybooks during two online visits separated by 6-8 weeks (M = 6.56, SD = 1.11; two books, order counterbalanced). Audio recordings were diarized, time-aligned, and orthographically transcribed using WebTrans. Conversational markers were calculated using R and word frequencies were calculated using Linguistic Inquiry and Word Count (LIWC) software. We examined links between child CU traits and linguistic markers, and explored whether relationships were moderated by child sex. RESULTS: Higher CU traits were associated with fewer positive emotion words produced by parents and children. Higher CU traits were also associated with greater concordance in the degree of interruptions and expression of anger emotion words by parents and children. CONCLUSIONS: Results suggest that objective linguistic correlates of CU traits are detectable during early childhood, which could inform adjunctive treatment modules that improve outcomes by precisely tracking and targeting subtle communication patterns.

Single-nucleus and spatial landscape of the sub-ventricular zone in human glioblastoma.

The sub-ventricular zone (SVZ) is the most well-characterized neurogenic area in the mammalian brain. We previously showed that in 65% of patients with glioblastoma (GBM), the SVZ is a reservoir of cancer stem-like cells that contribute to treatment resistance and emergence of recurrence. Here, we built a single-nucleus RNA-sequencing-based microenvironment landscape of the tumor mass (T_Mass) and the SVZ (T_SVZ) of 15 GBM patients and 2 histologically normal SVZ (N_SVZ) samples as controls. We identified a mesenchymal signature in the T_SVZ of GBM patients: tumor cells from the T_SVZ relied on the ZEB1 regulatory network, whereas tumor cells in the T_Mass relied on the TEAD1 regulatory network. Moreover, the T_SVZ microenvironment was predominantly characterized by tumor-supportive microglia, which spatially co-exist and establish heterotypic interactions with tumor cells. Lastly, differential gene expression analyses, predictions of ligand-receptor and incoming/outgoing interactions, and functional assays revealed that the IL-1ß/IL-1RAcP and Wnt-5a/Frizzled-3 pathways are therapeutic targets in the T_SVZ microenvironment. Our data provide insights into the biology of the SVZ in GBM patients and identify specific targets of this microenvironment.

Aotearoa genomic data repository: An ahuru mowai for taonga species sequencing data.

The Aotearoa Genomic Data Repository (AGDR) is an initiative to provide a secure within-nation option for the storage, management and sharing of non-human genomic data generated from biological and environmental samples originating in Aotearoa New Zealand. This resource has been developed to follow the principles of Maori Data Sovereignty, and to enable the right of kaitiakitanga (guardianship), so that iwi, hapu and whanau (tribes, kinship groups and families) can effectively exercise their responsibilities as guardians over biological entities that they regard as taonga (precious or treasured). While the repository is designed to facilitate the sharing of data-making it findable by researchers and interoperable with data held in other genomic repositories-the decision-making process regarding who can access the data is entirely in the hands of those holding kaitiakitanga over each data set. No data are made available to the requesting researcher until the request has been approved, and the conditions for access (which can vary by data set) have been agreed to. Here we describe the development of the AGDR, from both a cultural perspective, and a technical one, and outline the processes that underpin its operation.

Born into an isolating world: family-centred care for babies born to mothers with COVID-19.

Background: The benefits of facilitating breastmilk feeding and close contact between mother and neonate (family-centred care; FCC) in the perinatal period are well-established. The aim of this study was to determine how the delivery of FCC practices were impacted for neonates born to mothers with perinatal SARS-CoV-2 infection during the COVID-19 pandemic. Methods: Neonates born to mothers with confirmed SARS-CoV-2 infection during pregnancy were identified from the 'EsPnIC Covid paEdiatric NeonaTal REgistry' (EPICENTRE) multinational cohort between 10 March 2020 and 20 October 2021. The EPICENTRE cohort collected prospective data on FCC practices. Rooming-in and breastmilk feeding practice were the main outcomes, and factors influencing each were determined. Other outcomes included mother-baby physical contact prior to separation and the pattern of FCC components relative to time and local site guidelines. Findings: 692 mother-baby dyads (13 sites, 10 countries) were analysed. 27 (5%) neonates were positive for SARS-CoV-2 (14 (52%) asymptomatic). Most sites had policies that encouraged FCC during perinatal SARS-CoV-2 infection for most of the reporting period. 311 (46%) neonates roomed-in with their mother during the admission. Rooming-in increased over time from 23% in March-June 2020 to 74% in January-March 2021 (boreal season). 330 (93%) of the 369 separated neonates had no FCC physical contact with their mother prior, and 319 (86%) were asymptomatic. Maternal breastmilk was used for feeding in 354 (53%) neonates, increasing from 23% to 70% between March-June 2020 and January-March 2021. FCC was most impacted when mothers had symptomatic COVID-19 at birth. Interpretation: This is the largest report of global FCC practice during the COVID-19 pandemic to date. The COVID-19 pandemic may have impacted FCC despite low perinatal transmission rates. Fortunately, clinicians appear to have adapted to allow more FCC delivery as the COVID-19 pandemic progressed. Funding: The National Health and Medical Research Council (Australia): Grant ID 2008212 (DGT), Royal Children's Hospital Foundation: Grant ID 2019-1155 (EJP), Victorian Government Operational Infrastructure Support Program.

In vivo corrosion, tumor outcome, and microarray gene expression for two types of muscle-implanted tungsten alloys.

Tungsten alloys are composed of tungsten microparticles embedded in a solid matrix of transition metals such as nickel, cobalt, or iron. To understand the toxicology of these alloys, male F344 rats were intramuscularly implanted with pellets of tungsten/nickel/cobalt, tungsten/nickel/iron, or pure tungsten, with tantalum pellets as a negative control. Between 6 and 12 months, aggressive rhabdomyosarcomas formed around tungsten/nickel/cobalt pellets, while those of tungsten/nickel/iron or pure tungsten did not cause cancers. Electron microscopy showed a progressive corrosion of the matrix phase of tungsten/nickel/cobalt pellets over 6 months, accompanied by high urinary concentrations of nickel and cobalt. In contrast, non-carcinogenic tungsten/nickel/iron pellets were minimally corroded and urinary metals were low; these pellets having developed a surface oxide layer in vivo that may have restricted the mobilization of carcinogenic nickel. Microarray analysis of tumors revealed large changes in gene expression compared with normal muscle, with biological processes involving the cell cycle significantly up-regulated and those involved with muscle development and differentiation significantly down-regulated. Top KEGG pathways disrupted were adherens junction, p53 signaling, and the cell cycle. Chromosomal enrichment analysis of genes showed a highly significant impact at cytoband 7q22 (chromosome 7) which included mouse double minute (MDM2) and cyclin-dependant kinase (CDK4) as well as other genes associated with human sarcomas. In conclusion, the tumorigenic potential of implanted tungsten alloys is related to mobilization of carcinogenic metals nickel and cobalt from corroding pellets, while gene expression changes in the consequent tumors are similar to radiation induced animal sarcomas as well as sporadic human sarcomas.

Recent advancements and application of in vitro models for predicting inhalation toxicity in humans.

Animals have been indispensable in testing chemicals that can pose a risk to human health, including those delivered by inhalation. In recent years, the combination of societal debate on the use of animals in research and testing, the drive to continually enhance testing methodologies, and technology advancements have prompted a range of initiatives to develop non-animal alternative approaches for toxicity testing. In this review, we discuss emerging in vitro techniques being developed for the testing of inhaled compounds. Advanced tissue models that are able to recreate the human response to toxic exposures alongside examples of their ability to complement in vivo techniques are described. Furthermore, technology being developed that can provide multi-organ toxicity assessments are discussed.

I.V. acetaminophen pharmacokinetics in neonates after multiple doses.

BACKGROUND: Pharmacokinetics of an i.v. prodrug of acetaminophen (propacetamol) in neonates after repeat dosing are reported, with scant data for i.v. acetaminophen formulation. METHODS: Neonates from an intensive care unit received 6-hourly prn i.v. acetaminophen dosed according to postmenstrual age (PMA): 28-32 weeks, 10 mg kg(-1); 32-36 weeks, 12.5 mg kg(-1); and > or =36 weeks, 15 mg kg(-1). A maximum of five blood samples for assay and liver function tests (LFTs) were collected. A one-compartment linear disposition model (zero-order input; first-order elimination) was used to describe time-concentration profiles using population modelling (NONMEM). RESULTS: Fifty neonates, median (range) PMA 38.6 (32-45) weeks, mean (SD) weight 2.9 (0.7) kg, received a mean of 15 doses over a median 4 days with 189 serum acetaminophen and 231 LFT measurements. Standardized population parameter estimates for a term neonate were clearance (CL) 5.24 (CV 30.5%) litre h(-1) 70 kg(-1) and volume of distribution (V) 76 (29.6%) litre 70 kg(-1). CL increased with PMA from 4.4 litre h(-1) 70 kg(-1) at 34 weeks to 6.3 litre h(-1) 70 kg(-1) at 46 weeks. The presence of unconjugated hyperbilirubinaemia was associated with reduced CL: 150 micromol litre(-1) associated with 40% CL reduction. Acetaminophen concentrations between 10 and 23 mg litre(-1) at steady state are predicted after 15 mg kg(-1) 6-hourly for a neonate of PMA 40 weeks. Hepatic enzyme analysis of daily samples changed significantly for one patient whose alanine aminotransferase concentration tripled. CONCLUSIONS: The parameter estimates are similar to those described for propacetamol. There was no evidence of hepatotoxicity. Unconjugated hyperbilirubinaemia impacts upon CL, dictating dose reduction.

Identification of a second trans-acting gene controlling maltose fermentation in Saccharomyces carlsbergensis.

Maltose fermentation in Saccharomyces spp. requires the presence of a dominant MAL locus. The MAL6 locus has been cloned and shown to encode the structural genes for maltose permease (MAL61), maltase (MAL62), and a positively acting regulatory gene (MAL63). Induction of the MAL61 and MAL62 gene products requires the presence of maltose and the MAL63 gene. Mutations within the MAL63 gene produce nonfermenting strains unable to induce the two structural gene products. Reversion of these mal63 nonfermenters to maltose fermenters nearly always leads to the constitutive expression of maltase and maltose permease, and constitutivity is always linked to MAL6. We demonstrated that for one such revertant, strain C2, constitutivity did not require the MAL63 gene, since deletion disruption of this gene did not affect the constitutive expression of the structural genes. In addition, constitutivity was trans acting. Deletion disruption of the MAL6-linked structural genes for maltase and maltose permease in this strain did not affect the constitutive expression of a second, unlinked maltase structural gene. We isolated new maltose-fermenting revertants of a nonfermenting strain which carried a deletion disruption of the MAL63 gene. All 16 revertants isolated expressed maltase constitutively. In one revertant studied in detail, strain R10, constitutive expression was demonstrated to be linked to MAL6, semidominant, trans acting, and residing outside the MAL63-MAL61-MAL62 genes. From these studies we propose the existence of a second trans-acting regulatory gene at the MAL6 locus. We call this new gene MAL64. We mapped the MAL64 gene 2.3 centimorgans to the left of MAL63. The role of the MAL64 gene product in maltose fermentation is discussed.

Inverted DNA repeats: a source of eukaryotic genomic instability.

While inverted DNA repeats are generally acknowledged to be an important source of genetic instability in prokaryotes, relatively little is known about their effects in eukaryotes. Using bacterial transposon Tn5 and its derivatives, we demonstrate that long inverted repeats also cause genetic instability leading to deletion in the yeast Saccharomyces cerevisiae. Furthermore, they induce homologous recombination. Replication plays a major role in the deletion formation. Deletions are stimulated by a mutation in the DNA polymerase delta gene (pol3). The majority of deletions result from imprecise excision between small (4- to 6-bp) repeats in a polar fashion, and they often generate quasipalindrome structures that subsequently may be highly unstable. Breakpoints are clustered near the ends of the long inverted repeats (< 150 bp). The repeats have both intra- and interchromosomal effects in that they also create hot spots for mitotic interchromosomal recombination. Intragenic recombination is 4 to 18 times more frequent for heteroalleles in which one of the two mutations is due to the insertion of a long inverted repeat, compared with other pairs of heteroalleles in which neither mutation has a long repeat. We propose that both deletion and recombination are the result of altered replication at the basal part of the stem formed by the inverted repeats.

Responses to increasing amounts of high-oleic sunflower fatty acids infused into the abomasum of lactating dairy cows.

Increasing the oleic acid (18:1 cis-9) content of milk fat might be desirable to meet consumer concerns about dietary healthfulness and for certain manufacturing applications. The extent to which milk fat could be enriched with oleic acid is not known. Increasing the intestinal supply of polyunsaturated fatty acids decreases dry matter intake (DMI) in cows, but the effects of oleic acid have not been quantified. In a crossover design, 4 multiparous Holstein cows were abomasally infused with increasing amounts (0, 250, 500, 750, or 1,000 g/d) of free fatty acids from high-oleic sunflower oil (HOSFA) or with carrier alone. Continuous infusions (20 to 22 h/d) were for 7 d at each amount. Infusions were homogenates of HOSFA with 240 g/d of meat solubles and 11.2 g/d of Tween 80; controls received carrier only. The HOSFA contained (by wt) 2.4% 16:0, 1.8% 18:0, 91.4% 18:1 cis-9, and 2.4% 18:2. The DMI decreased linearly (range 22.0 to 5.8 kg/d) as the infused amount of HOSFA increased. Apparent total tract digestibilities of dry matter, organic matter, neutral detergent fiber, and energy decreased as the infusion increased to 750 g/d and then increased when 1,000 g/d was infused. Digestibility of total fatty acids increased linearly as infused fatty acids increased. Yields of milk, fat, true protein, casein, and total solids decreased quadratically as infused amounts increased; decreases were greatest when 750 or 1,000 g/d of HOSFA were infused. Concentrations of fat and total solids increased at the higher amounts of HOSFA. The volume mean diameter of milk fat droplets and the diameter below which 90% of the volume of milk fat is contained both increased as HOSFA infusion increased. Concentrations of short-chain fatty acids, 12:0, 14:0, and 16:0 in milk fat decreased linearly as HOSFA increased. The concentration of 18:1 cis-9 (19.4 to 57.4% of total fatty acids) increased linearly as HOSFA infusion increased. Concentrations of 18:1 cis-9 in blood triglyceride-rich lipoproteins increased linearly as infusion increased, whereas contents of 14:0, 16:0, 18:0, total 18:1 trans, and 18:2n-6 decreased linearly. The composition and physical characteristics of milk fat can be altered markedly by an increased intestinal supply of 18:1 cis-9, which could influence processing characteristics and the healthfulness of milk fat. However, an increased supply of free 18:1 cis-9 to the intestine decreased DMI and milk production.

Quantitative analysis of gemcitabine triphosphate in human peripheral blood mononuclear cells using weak anion-exchange liquid chromatography coupled with tandem mass spectrometry.

Gemcitabine triphosphate (dFdCTP) is a highly active metabolite of gemcitabine. It is formed intra-cellularly via the phosphorylation of gemcitabine by deoxycytidine kinase. The monitoring of dFdCTP in human peripheral blood mononuclear cells (PBMCs), in addition to plasma concentrations of gemcitabine and its metabolite 2',2'-difluorodeoxyuridine, is considered very useful in determining pharmacokinetic-pharmacodynamic relationships. We describe a novel sensitive assay for the quantification of dFdCTP in human PBMCs. The method is based on weak anion-exchange liquid chromatography and detection with tandem mass spectrometry (LC-MS/MS). The assay has been validated from 1 ng/ml (lower limit of quantification, LLOQ) to 25 ng/ml (upper limit of quantification, ULOQ) using 180 microl aliquots of PBMC extracts containing approximately 0.648 mg protein or 3.8 x 10(6) lysed PBMCs. The LLOQ is equivalent to 94 fmol/10(6) cells (1 ng/ml = 0.18 ng/180 microl or 0.18 ng/0.648 mg protein = 0.047 ng/10(6) cells or 94 fmol/10(6) cells). This highly sensitive assay is capable of quantifying about 200-fold lower concentrations of dFdCTP in human PBMCs than currently available methods.

Bimolecular networks and supramolecular traps on Au(111).

We demonstrate the formation of intermixed phases and self assembled molecular templates on the Au(111) surface. The templates are stabilized by hydrogen bonding between melamine molecules with trigonal symmetry and linear PTCDI (perylene tetra-carboxylic di-imide) molecules. When annealed, these molecules spontaneously form either a chiral intermixed phase or a honeycomb arrangement in which vertexes and edges correspond respectively to melamine and PTCDI molecules. We also observe minority phases with more complex intermolecular junctions. The use of these networks as templates is demonstrated by the controlled capture of fullerenes within the pores of the network to form dimers, hexamers, and heptamers. Our results confirm that bimolecular templates can be realized on a range of substrates.

Development of fewer tumor colonies in lungs of athymic nude mice after intravenous injection of tumor cells.

The formation of tumor colonies was compared in the lungs of athymic nude and normal littermate mice after an iv injection of transplantable syngeneic tumor cells. Each of 5 tumors tested formed fewer colonies in the lungs of nude recepients.

Immunodepression, a noncontributor to radiation-induced leukemogenesis of the RFM mouse.

Following a single acute exposure to 300 R of X-rays at 6 weeks old, approximately 65% of female RFM mice die of thymic lymphoma during the first year of life. In contrast, nonirradiated animals do not die of this neoplasm during this same period. To determine if immediate immunological restoration is of significance in interrupting the inductive process, we injected 50 X 10(6) syngeneic spleen or bone marrow cells into these animals immediately following X-irradiation. Restoration of immunocompetence as measured by both humoral and cell-mediated parameters was more rapid in spleen cell-reconstituted animals than in bone marrow-treated animals; however, spleen cells failed to protect the mice against the irradiation-induced thymic lymphomas. In contrast, although there was no significant difference in the immunological recovery of bone marrow-reconstituted animals and animals that received only irradiation, mortality was dramatically reduced as a result of marrow injection. Therefore, although immunodepression is an inherent component, it cannot be considered as a critical obligatory requirement in the pathogenesis of radiation-induced thymic lymphomas of RFM mice.

Novel inhibitors of poly(ADP-ribose) polymerase/PARP1 and PARP2 identified using a cell-based screen in yeast.

Multicellular organisms must have means of preserving their genomic integrity or face catastrophic consequences such as uncontrolled cell proliferation or massive cell death. One response is a modification of nuclear proteins by the addition and removal of polymers of ADP-ribose that modulate the properties of DNA-binding proteins involved in DNA repair and metabolism. These ADP-ribose units are added by poly(ADP-ribose) polymerase (PARP) and removed by poly(ADP-ribose) glycohydrolase. Although budding yeast Saccharomyces cerevisiae does not possess proteins with significant sequence similarity to the human PARP family of proteins, we identified novel small molecule inhibitors against two family members, PARP1 and PARP2, using a cell-based assay in yeast. The assay was based on the reversal of growth inhibition caused by the heterologous expression of either PARP1 or PARP2. Validation of the assay was achieved by showing that the growth inhibition was relieved by a mutation in a single residue in the catalytic site of PARP1 or PARP2 or exposure of yeast to a known PARP1 inhibitor, 6(5H)-phenanthridinone. In separate experiments, when a putative protein regulator of PARP activity, human poly(ADP-ribose) glycohydrolase, was coexpressed with PARP1 or PARP2, yeast growth was restored. Finally, the inhibitors identified by screening the yeast assay are active in a mammalian PARP biochemical assay and inhibit PARP1 and PARP2 activity in yeast cell extracts. Thus, our data reflect the strength of using yeast to identify small molecule inhibitors of therapeutically relevant gene families, including those that are not found in yeast, such as PARP. The resultant inhibitors have two critical uses (a) as leads for drug development and (b) as tools to dissect cellular function.