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Introduction: Assessment for learning has many benefits, but learners will still encounter high-stakes decisions about their performance throughout training. It is unknown if assessment for learning can be promoted with a combination model where scores from some assessments are factored into course grades and scores from other assessments are not used for course grading., Methods: At the University of Utah School of Medicine, year 1-2 medical students (MS) completed multiple-choice question quiz assessments and final examinations in six systems-based science courses. Quiz and final examination performance counted toward course grades for MS2017-MS2018. Starting with the MS2020 cohort, quizzes no longer counted toward course grades. Quiz, final examination, and Step 1 scores were compared between ungraded quiz and graded quiz cohorts with independent samples t -tests. Student and faculty feedback was collected., Results: Quiz performance was not different for the ungraded and graded cohorts ( p  = 0.173). Ungraded cohorts scored 4% higher on final examinations than graded cohorts ( p  ≤ 0.001, d  = 0.88). Ungraded cohorts scored above the national average and 11 points higher on Step 1 compared to graded cohorts, who had scored below the national average ( p  ≤ 0.001, d  = 0.64). During the study period, Step 1 scores increased by 2 points nationally. Student feedback was positive, and faculty felt it improved their relationship with students., Discussion: The change to ungraded quizzes did not negatively affect final examination or Step 1 performance, suggesting a combination of ungraded and graded assessments can effectively promote assessment for learning., Competing Interests: Conflict of InterestThe authors declare no competing interests., (© The Author(s) under exclusive licence to International Association of Medical Science Educators 2022, Springer Nature or its licensor holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)

Objective: Determine non-invasive ventilation with continuous positive airway pressure (CPAP) outcomes for paediatric respiratory distress in low-income and middle-income countries (LMICs)., Design: Systematic review and meta-analysis., Setting: LMIC hospitals., Patients: One month to 15 year olds with respiratory distress., Interventions: We searched Medline, Embase, LILACS, Web of Science and Scopus on 7 April 2020. Included studies assessed CPAP safety, efficacy or effectiveness. All study types were included; neonatal only studies were excluded. Data were extracted by two reviewers and bias was assessed. Certainty of evidence was evaluated, and risk ratios (RR) were produced for meta-analyses. (PROSPERO protocol CRD42018084278)., Results: 2174 papers were screened, 20 were included in the systematic review and 3 were included in two separate meta-analyses of mortality and adverse events. Studies suitable for meta-analysis were randomised controlled trials (RCTs) from Bangladesh, Ghana and Malawi. For meta-analyses comparing death or adverse events between CPAP and low-flow oxygen recipients, we found no clear CPAP effect on mortality (RR 0.75, 95% CI 0.33 to 1.72) or adverse events (RR 1.52, CI 0.71 to 3.26). We downgraded the certainty of evidence for both death and adverse events outcomes to 'low' due to design issues and results discrepancies across RCTs., Conclusions: Evidence for CPAP efficacy against mortality and adverse events has low certainty and is context dependent. Hospitals introducing CPAP need to have mechanisms in place to optimise safety in the context it is being used; this includes the location (a high dependency or intensive care area), adequate numbers of staff trained in CPAP use, close monitoring and mechanisms for escalation, daily direct physician supervision, equipment that is age appropriate and user-friendly and continuous monitoring of outcomes and quality of care., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Although HIV infection, severe malnutrition and hypoxaemia are associated with high mortality in children with WHO-defined severe pneumonia in sub-Saharan Africa, many do not have these conditions and yet mortality remains elevated compared with high-resource settings. Further stratifying mortality risk for children without these conditions could permit more strategic resource utilisation and improved outcomes. We therefore evaluated associations between mortality and clinical characteristics not currently recognised by the WHO as high risk among children in Malawi with severe pneumonia but without HIV (including exposure), severe malnutrition and hypoxaemia., Methods: Between May 2016 and March 2018, we conducted a prospective observational study alongside a randomised controlled trial (CPAP IMPACT) at Salima District Hospital in Malawi. Children aged 1-59 months hospitalised with WHO-defined severe pneumonia without severe malnutrition, HIV and hypoxaemia were enrolled. Study staff assessed children at admission and ascertained hospital outcomes. We compared group characteristics using Student's t-test, rank-sum test, χ 2 test or Fisher's exact test as appropriate., Results: Among 884 participants, grunting (10/112 (8.9%) vs 11/771 (1.4%)), stridor (2/14 (14.2%) vs 19/870 (2.1%)), haemoglobin <50 g/L (3/27 (11.1%) vs 18/857 (2.1%)) and malaria (11/204 (5.3%) vs 10/673 (1.4%)) were associated with mortality compared with children without these characteristics. Children who survived had a 22 g/L higher mean haemoglobin and 0.7 cm higher mean mid-upper arm circumference (MUAC) than those who died., Conclusion: In this single-centre study, our analysis identifies potentially modifiable risk factors for mortality among hospitalised Malawian children with severe pneumonia: specific signs of respiratory distress (grunting, stridor), haemoglobin <50 g/L and malaria infection. Significant differences in mean haemoglobin and MUAC were observed between those who survived and those who died. These factors could further stratify mortality risk among hospitalised Malawian children with severe pneumonia lacking recognised high-risk conditions., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY. Published by BMJ.)

Regulation of 5-aminolevulinate synthase 1 (ALAS1) for nonerythroid heme is critical for respiration, cell signaling mechanisms and steroid/drug metabolism. ALAS1 is induced in some genetic disorders but unlike other genes in the heme pathway, a gene variant of ALAS1 associated with inherited disease has not been reported. BALB/c mice carrying a null ALAS1 allele caused by a βGEO insert were developed and used to determine the consequences of heme demand of a semi gene copy number. Homozygous disruption of ALAS1 (-/-) was lethal for embryo development post day 6.5 but expression in heterozygotes (+/-) was sufficient for the number of offspring and survival. In both wild type (WT +/+) and +/- mice expression of ALAS1 RNA was greatest in liver and harderian gland and much lower in kidney, lung, heart, brain and spleen. The effects of one WT ALAS1 allele in +/- mice on mRNA levels in liver and harderian gland were less marked compared to brain and other organs that were examined. Many other genes were up-regulated by heterozygosity in liver and brain but to a minimal extent. Hepatic heme oxygenase 1 (HMOX1) mRNA expression was significantly lower in +/- mice but not in brain. No elevated translation of WT allele ALAS1 mRNA was detected in +/- liver as a compensatory mechanism for the disabled allele. Fasting induced ALAS1 mRNA in both WT and +/- mice but only in +/- was this manifest as increased ALAS1 protein. The hepatic protoporphyria-inducing drug 4-ethyl-DDC caused induction of hepatic ALAS1 mRNA and protein levels in both WT and +/- mice but markedly less in the mice with only one intact allele. The findings illustrate the complex response of ALAS1 expression for heme demand but limited evidence that upregulation of a wild type allele can compensate for a null allele., (© 2021 The Authors.)

Neutralizing antibodies elicited by HIV-1 coevolve with viral envelope proteins (Env) in distinctive patterns, in some cases acquiring substantial breadth. We report that primary HIV-1 envelope proteins-when expressed by simian-human immunodeficiency viruses in rhesus macaques-elicited patterns of Env-antibody coevolution very similar to those in humans, including conserved immunogenetic, structural, and chemical solutions to epitope recognition and precise Env-amino acid substitutions, insertions, and deletions leading to virus persistence. The structure of one rhesus antibody, capable of neutralizing 49% of a 208-strain panel, revealed a V2 apex mode of recognition like that of human broadly neutralizing antibodies (bNAbs) PGT145 and PCT64-35S. Another rhesus antibody bound the CD4 binding site by CD4 mimicry, mirroring human bNAbs 8ANC131, CH235, and VRC01. Virus-antibody coevolution in macaques can thus recapitulate developmental features of human bNAbs, thereby guiding HIV-1 immunogen design., (Copyright © 2021, American Association for the Advancement of Science.)

: Low molecular weight heparins are used during haemodialysis for thromboprophylaxis of the dialysis circuit, with plasma antifactor-Xa (anti-Xa) activity used as a surrogate measure for effective anticoagulation. However, this pharmacokinetic parameter does not always correlate with pharmacodynamic effects in patients. The aim of this study was to investigate the relationship between actual plasma levels of the low molecular weight heparins enoxaparin, anti-Xa activity, and global coagulation measurement of thrombin generation during haemodialysis. Blood was analysed from 16 adult patients with end-stage kidney disease at 0, 2, 4 h, and at completion of 31 dialysis sessions where single fixed doses of 20 (n = 3), 40 (n = 16), 60 (n = 6), or 80 (n = 6) mg of enoxaparin (equating to 0.23-1.07 mg/kg) were used as thromboprophylaxis. Plasma enoxaparin oligosaccharides [degree of polymerization (dp)6-dp16] were measured by high-performance size exclusion chromatography, anti-Xa activity by colourimetric assay, and thrombin generation by calibrated automated thrombogram. Plasma enoxaparin fragments were undetectable at the beginning of each dialysis, peaked at 2 h to levels that correlated with dose (r = 0.68, P < 0.001) then remained relatively stable. In contrast, therapeutic anti-Xa levels achieved at 2 h in 18 cases (58%) quickly dropped to only six cases (19%) at the end of dialysis, by which time thrombin generation had also recovered in 81% of patients. Statistical modelling revealed a threshold value of anti-Xa at 0.53 IU/ml that supressed thrombin generation to 15.28% of baseline (P < 0.001). Despite loss of anticoagulant activity in the majority of patients, plasma levels of enoxaparin oligosaccharides remained detectable and relatively unchanged throughout dialysis.

Objectives: No consensus exists on a standardized critical care content outline for medical student education. The aim of this research is to develop a national undergraduate medical education critical care content outline., Design: The authors used a Delphi process to reach expert consensus on a content outline that identified the core critical care knowledge topics and procedural skills that medical students should learn prior to entering residency. Over three iterative rounds, the expert panel reached consensus on a critical care content outline., Setting: An electronic survey of critical care medical educators, residency program directors, and residents in the United States., Subjects: The expert panel included three groups as follows: 1) undergraduate medical education critical care educators, 2) residency program directors representing all core specialties, and 3) residents representing their core specialties., Interventions: None., Measurements and Main Results: The expert panel included 28 members. Experts represented the following medical specialties: anesthesiology, emergency medicine, internal medicine, obstetrics and gynecology, pediatrics, and surgery. Seventeen experts had subspecialty training in critical care. The expert panel identified 19 highly recommended critical care knowledge topics and procedural skills. These topics and procedural skills were grouped into five broad categories as follows: 1) neurologic, 2) respiratory, 3) cardiovascular, 4) renal and electrolytes, and 5) supplemental ICU topics. Bag-mask ventilation was the only procedural skill identified as highly recommended., Conclusions: This study provides a national consensus undergraduate medical education critical care content outline. By including experts from multiple specialties, this content outline is meaningful for medical student education, independent of medical specialty. The content outline represents a first step in the development of a national undergraduate medical education critical care curriculum.

Background: Pneumonia is the leading cause of death among children globally. Most pneumonia deaths in low-income and middle-income countries (LMICs) occur among children with HIV infection or exposure, severe malnutrition, or hypoxaemia despite antibiotics and oxygen. Non-invasive bubble continuous positive airway pressure (bCPAP) is considered a safe ventilation modality that might improve child pneumonia survival. bCPAP outcomes for high-risk African children with severe pneumonia are unknown. Since most child pneumonia hospitalisations in Africa occur in non-tertiary district hospitals without daily physician oversight, we aimed to examine whether bCPAP improves severe pneumonia mortality in such settings., Methods: This open-label, randomised, controlled trial was done in the general paediatric ward of Salima District Hospital, Malawi. We enrolled children aged 1-59 months old with WHO-defined severe pneumonia and either HIV infection or exposure, severe malnutrition, or an oxygen saturation of less than 90%. Children were randomly assigned 1:1 to low-flow nasal cannula oxygen or nasal bCPAP. Non-physicians administered care; the primary outcome was hospital survival. Primary analyses were by intention-to-treat and interim and adverse events analyses per protocol. This trial is registered with ClinicalTrials.gov, number NCT02484183, and is closed., Findings: We screened 1712 children for eligibility between June 23, 2015, and March 21, 2018. The data safety and monitoring board stopped the trial for futility after 644 of the intended 900 participants were enrolled. 323 children were randomly assigned to oxygen and 321 to bCPAP. 35 (11%) of 323 children who received oxygen died in hospital, as did 53 (17%) of 321 who received bCPAP (relative risk 1·52; 95% CI 1·02-2·27; p=0·036). 13 oxygen and 17 bCPAP patients lacked hospital outcomes and were considered lost to follow-up. Suspected adverse events related to treatment occurred in 11 (3%) of 321 children receiving bCPAP and 1 (<1%) of 323 children receiving oxygen. Four bCPAP and one oxygen group deaths were classified as probable aspiration episodes, one bCPAP death as probable pneumothorax, and six non-death bCPAP events included skin breakdown around the nares., Interpretation: bCPAP treatment in a paediatric ward without daily physician supervision did not reduce hospital mortality among high-risk Malawian children with severe pneumonia, compared with oxygen. The use of bCPAP within certain patient populations and non-intensive care settings might carry risk that was not previously recognised. bCPAP in LMICs needs further evaluation before wider implementation for child pneumonia care., Funding: Bill & Melinda Gates Foundation, International AIDS Society, Health Empowering Humanity., (Copyright © 2019 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

The haem biosynthetic pathway is of fundamental importance for cellular metabolism both for the erythroid and nonerythroid tissues. There are several genetic variants of the pathway in the human population that cause dysfunction of one or other of the enzymes resulting in porphyrias of varying severity. Serious chronic hepatic and systemic diseases may result. Some of these can be precipitated by exposure to drugs including hormones, barbiturates and antibiotics, as well as alcohol and particular chlorinated aromatic chemicals. In experimental animals some of the steps of this pathway can also be severely disrupted by a variety of environmental chemicals, potential drugs and pesticides, especially in the liver, leading to the accumulation of uroporphyrins derived from the intermediate uroporphyrinogens or protoporphyrin IX, the immediate precursor of haem. With some of these chemicals this also leads to cholestasis and liver cell injury and eventually hepatic tumours. The review evaluates the available evidence linking hepatic porphyria with carcinogenesis in naturally occurring human genetic conditions and in chemically-induced porphyrias in laboratory animals. The existing data showing gender, strain, and species differences in sensitivity to the chemical-induced porphyrias, liver injury and liver tumours are discussed and the role that transgenically altered mouse models have played in defining the varying mechanisms. Finally, the review proposes a novel, unifying hypothesis linking the hepatotoxicity induced by the accumulation of various porphyrins, with the increased risk of developing hepatic cancer as a long term consequence.

Populations often exist, either by choice or by external pressure, in a fragmented way, referred to as a metapopulation. Typically, the dynamics accounted for within metapopulation models are assumed to be static. For example, patch occupancy models often assume that the colonisation and extinction rates do not change, while spatially structured models often assume that the rates of births, deaths and migrations do not depend on time. While some progress has been made when these dynamics are changing deterministically, less is known when the changes are stochastic. It can be quite common that the environment a population inhabits determines how these dynamics change over time. Changes to this environment can have a large impact on the survival probability of a population and such changes will often be stochastic. The typical metapopulation model allows for catastrophes that could eradicate most, if not all, individuals on an entire patch. It is this type of phenomenon that this article addresses. A Markov process is developed that models the number of individuals on each patch within a metapopulation. An approximation for the original model is presented in the form of a piecewise-deterministic Markov process and the approximation is analysed to present conditions for extinction., (Copyright © 2017 Elsevier Inc. All rights reserved.)

A new functional law of large numbers to approximate a time inhomogeneous Markov process that is only density dependent in the limit as an index parameter goes to infinity is developed. This extends previous results by other authors to a broader class of Markov processes while relaxing some of the conditions required for those results to hold. This result is applied to a stochastic metapopulation model that accounts for spatial structure as well as within patch dynamics with the novel addition of time dependent dynamics. The resulting nonautonomous differential equation is analysed to provide conditions for extinction and persistence for a number of examples. This condition shows that the migration of a species will positively impact the reproduction in less populated areas while negatively impacting densely populated areas., (Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.)

We develop a stochastic metapopulation model that accounts for spatial structure as well as within patch dynamics. Using a deterministic approximation derived from a functional law of large numbers, we develop conditions for extinction and persistence of the metapopulation in terms of the birth, death and migration parameters. Interestingly, we observe the Allee effect in a metapopulation comprising two patches of greatly different sizes, despite there being decreasing patch specific per-capita birth rates. We show that the Allee effect is due to the way the migration rates depend on the population density of the patches., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Many toxicological disorders, in common with numerous human diseases, are probably the consequence of multigene interactions with a variety of chemical and physiological factors. The importance of genetic factors may not be obvious initially from association studies because of their complexity and variable penetrance. The human disease, porphyria cutanea tarda (PCT), is a skin disease caused by the photosensitizing action of porphyrins arising secondary to the decreased activity of an enzyme of heme biosynthesis, uroporphyrinogen decarboxylase (UROD), in the liver. It is triggered by idiosyncratic hepatic interaction between genetic factors and chemicals such as alcohol, estrogenic drugs, and polyhalogenated aromatics. PCT and its animal models are known collectively as the hepatic uroporphyrias. There is strong evidence for the participation of iron in the pathogenesis of these conditions. Mouse models have been used to explore the relative importance of a variety of agents such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), alcohol, and iron in the development of uroporphyria and to elucidate the mechanism of the depression of hepatic UROD activity. Mutations of the UROD and hemochromatosis (HFE) genes are genetic factors in some PCT patients which can be mimicked in mice heterozygous for the Hfe and Urod null genes. Association studies of uroporphyria induced by TCDD or hexachlorobenzene with DNA markers in mouse intercrosses have shown the participation of other, unknown, genetic factors in addition to the strong influence of the Ahr gene. The pathogenesis of hepatic uroporphyrias exemplifies the complexity of the interactions between chemical and genetic factors that can contribute to the hepatotoxicity of chemicals.

Background: The rate of development of further basal cell carcinoma (BCC) after first presentation is highly variable. The mechanisms that determine this phenotypic difference are unclear., Objective: We assessed the risks of developing a subsequent BCC in patients who developed a BCC and a squamous cell carcinoma (SCC) and compared them with patients who developed a BCC only., Methods: In all, 1040 patients who developed BCC only were compared with 140 patients who developed BCC and SCC to see whether the latter group included a high proportion of risk phenotypes (eg, male sex and fair skin). We then compared the number of BCCs developing per year in the two groups (174 BCC only and 71 BCC/SCC) during a 5-year period after initial BCC presentation., Results: The BCC/SCC group demonstrated a significantly lower BCC/year rate than BCC only group. The rate of development of further BCC during 5-year follow-up was lower in the BCC/SCC group because a smaller number of patients developed subsequent BCC and not because the same proportion of patients developed lesions but in smaller numbers. After 5 years of follow-up, 51.1% of BCC and 74.6% of BCC/SCC cases were free from a subsequent BCC. Logistic regression analysis corrected for age at initial presentation confirmed that patients with BCC/SCC were less likely to develop a further BCC during the 5 years after initial presentation (P = .001, odds ratio = 0.31, 95% confidence interval 0.15-0.63)., Limitations: Because of the large patient group and long study follow-up from the date of the index BCC or SCC, not all data were obtained. Where this is the case, the number of patients for whom the information is available is provided., Conclusions: Patients who develop a BCC are similar to patients who develop both a BCC and SCC, confirming the overlap of causative factors. Patients who develop both a BCC and SCC are less likely to develop BCCs compared with patients who develop BCC only.

The consequences of exposure of people to highly chlorinated polychlorodibenzo-p-dioxins (PCDDs) are much less known than those of TCDD. We report on levels of PCDDs (and PCDFs) in 13 members of two families poisoned by contaminated cooking oil. Originally, all persons displayed chloracne as an early symptom. Persisting hexa- and higher chlorinated PCDDs could be analysed many years after exposure. Highest values found in blood lipids were: OCDD 660,000 pg/g; HpCDD 58,000 pg/g; HxCDDs: 3500 pg/g. None of the participants exhibited increased TCDD levels at the time of study. During a period of 6 years, HpCDD and OCDD disappeared from the blood lipids much faster in persons exposed as children or young adults, than from lipids of their parents. Surface receptors on blood lymphocytes of the members of the two families and the proliferative capacity of these blood cells in the presence of typical stimulants were analysed. Even in family members with the highest body burdens of hexa- to octachlorinated PCDDs we could not detect pronounced changes from a reference population with respect to the immunological markers. Minor deviations of levels of some receptors in a few, but not all, highly exposed persons suggested a similar trend to those reported in previous studies of persons with body burdens of > or =3000 pg TCDD/g blood lipids. An increase in the number of total blood lymphocytes in some subjects exposed as children may have similarity with highly TCDD-exposed children in Seveso.

The dysfunction of hepatic heme synthesis by 2,3,7,8-tetrachlordibenzo- p-dioxin (TCDD) in mice, enhanced by iron, leads to accumulation of uroporphyrins I and III (uroporphyria) and resembles the human disorder porphyria cutanea tarda (PCT) precipitated by alcohol and estrogenic drugs. Although consequences of TCDD are considered entirely dependent on the aryl hydrocarbon receptor (AHR), this is not proven for uroporphyria. Administration of TCDD (75 microg/kg) caused uroporphyria in susceptible C57BL/6J mice with high-affinity AHR after 5 weeks (>600-fold increase in hepatic uroporphyrins). Transcriptomics showed significant modified gene expressions for intermediary, heme, and iron metabolism as well as for oxidative stress and cell injury. Resistant low-affinity AHR DBA/2 mice (no increase in porphyrins) showed far fewer changes. At this dose of TCDD, persistent up-regulation of some traditional AH battery genes occurred in both strains. Essentiality of AHR was demonstrated with C57BL/6 Ahr knockout mice. Elevation of hepatic uroporphyrins was 964-fold in Ahr (+/+) mice, lower in Ahr (+/-) (60-fold), but undetectable with Ahr (-/-) . Consistent with an oxidative mechanism, iron overload enhanced porphyria as well as general liver injury in Ahr (+/+) and Ahr (+/-) mice but had no interactive effect in Ahr (-/-) . In contrast, when iron-treated mice received, instead of TCDD, the heme precursor 5-aminolevulinic acid (ALA), causing uroporphyia in Ahr (+/+) mice (242-fold rise in uroporphyrins), elevation of uroporphyrins I and III (42-fold) also occurred in Ahr (-/-) mice and was seemingly associated with AHR-independent expression of Cyp1a2. The findings prove that AHR is a key factor in porphyria induced in mice by TCDD. However, in other models of human PCT, participation of AHR may not be an essential requirement.

Trachoma is the leading infectious cause of blindness in the world. Areas where it is most prevalent also have some of the highest rates of childhood malnutrition. We examined the relationship between both acute and chronic malnutrition and clinical trachoma. We also explored whether malnutrition alters the clinical manifestations of the disease. Children with chronic malnutrition, but not acute malnutrition, were more likely to have clinical trachoma. Stunted children are 1.96 times more likely to have clinical trachoma than nonstunted children (95% CI: 1.12-3.43), even after controlling for age, gender and infection status of other household members. Host factors including malnutrition may play a role in determining disease manifestations.

Background: One previous study has shown a higher prevalence of sebaceous hyperplasia (SH) in patients with heart transplant on immunosuppressive drugs as compared with sex-matched control patients., Objective: We set out to compare the prevalence of SH in a cohort of patients undergoing renal transplant with age- and sex-matched control patients and to find any association with nonmelanoma skin cancer (NMSC) in these patients., Methods: In all, 117 patients with renal transplant and 117 age- and sex-matched control patients were screened for the prevalence of SH and NMSC., Results: We found that 29.9% of our patients with renal transplant had SH; 16 of 35 (45.7%) of these patients had a history of NMSC as compared with 6 of 82 (7.3%) patients without SH (P < .001, odds ratio 10.7). In the age- and sex-matched control group, a total of 28 patients (23.9%) had one or more lesions of SH., Limitations: This study is small and will require confirmation with larger cohort studies., Conclusions: In our cohort of patients with renal transplant we found a strong association of NMSC with SH. This association remained significant after correction of factors such as age, sex, skin type, and duration of transplant.

Differential gene expression in two established initiation and promotion skin carcinogenesis models during promotion and tumor formation was determined by microarray technology with the purpose of distinguishing the genes more associated with neoplastic transformation from those linked with proliferation and differentiation. The first model utilized dimethylbenz[a]anthracene initiation and 12-O-tetradecanoylphorbol 13-acetate (TPA) promotion in the FVB/N mouse, and the second TPA promotion of the Tg.Ac mouse, which is endogenously initiated by virtue of an activated Ha-ras transgene. Comparison of gene expression profiles across the two models identified genes whose altered expression was associated with papilloma formation rather than TPA-induced proliferation and differentiation. DMBA suppressed TPA-induced differentiation which allowed identification of those genes associated more specifically with differentiation rather than proliferation. EASE (Expression Analysis Systemic Explorer) indicated a correlation between muscle-associated genes and skin differentiation, whereas genes involved with protein biosynthesis were strongly correlated with proliferation. For verification the altered expression of selected genes were confirmed by RT-PCR; Carbonic anhydrase 2, Thioredoxin 1 and Glutathione S-transferase omega 1 associated with papilloma formation and Enolase 3, Cystatin beta and Filaggrin associated with TPA-induced proliferation and differentiation. In situ analysis located the papillomas Glutathione S-transferase omega 1 expression to the proliferating areas of the papillomas. Thus we have identified profiles of differential gene expression associated with the tumorigenesis and promotion stages for skin carcinogenesis in the mouse.

Polymorphisms of genes linked to iron metabolism may account for individual variability in hemochromatosis and iron status connected with liver and cardiovascular diseases, cancers, toxicity, and infection. Mouse strains exhibit marked differences in levels of non-heme iron, with C57BL/6J and SWR showing low and high levels, respectively. The genetic basis for this variability was examined using quantitative trait loci (QTL) analysis together with expression profiling and chromosomal positions of known iron-related genes. Non-heme iron levels in liver and spleen of C57BL/6J x SWR F2 mice were poorly correlated, indicating independent regulation. Highly significant (P < .01) polymorphic loci were found on chromosomes 2 and 16 for liver and on chromosomes 8 and 9 for spleen. With sex as a covariate, additional significant or suggestive (P < 0.1) QTL were detected on chromosomes 7, 8, 11, and 19 for liver and on chromosome 2 for spleen. A gene array showed no clear association between most loci and differential iron-related gene expression. The gene for transferrin and a transferrin-like gene map close to the QTL on chromosome 9. Transferrin saturation was significantly lower in C57BL/6J mice than in SWR mice, but there was no significant difference in the serum level of transferrin, hepatic expression, or functional change in cDNA sequence. beta2-Microglobulin, which, unlike other loci, was associated with C57BL/6J alleles, is a candidate for the chromosome 2 QTL for higher iron. In conclusion, the findings show the location of polymorphic genes that determine basal iron status in wild-type mice. Human equivalents may be pertinent in predisposition to hepatic and other disorders.

Although the influence of p53 deficiency on somatic genetic stability is well established, its effect in the germline is poorly understood. Mutation rates at two expanded simple tandem repeat (ESTR) loci were studied in the germline of nonexposed and irradiated p53-deficient mice. Spontaneous mutation rates in the homozygous and heterozygous p53-deficient males did not significantly differ from that in the isogenic wild-type mice. Acute exposure to 1 Gy of X rays resulted in a similar increase in mutation rates across males with different p53 genotypes. ESTR mutation spectra did not significantly differ across males with different p53 genotypes. Taken together, these results suggest that p53-deficiency does not affect spontaneous and radiation-induced mutation in the mouse germline.

BALB/c Fech(m1Pas) mice have a mutated ferrochelatase gene resulting in protoporphyria that models the hepatic injury occurring sporadically in human erythropoietic protoporphyria. We used this mouse model to study the development of the injury and to compare the dysfunction of heme synthesis with hepatic gene expression of liver metabolism, oxidative stress, and cellular injury/inflammation. From an early age expression of total cytochrome P450 and many of its isoforms was significantly lower than in wild-type mice. However, despite massive accumulation of protoporphyrin in the liver, expression of the main genes controlling heme synthesis and catabolism (Alas1 and Hmox1, respectively) were only modestly affected even in the presence of the cytochrome P450-inducing CAR agonist 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene. In contrast, in BALB/c mice exhibiting griseofulvin-induced hepatic protoporphyria with induction and destruction of cytochrome P450, both Alas1 and Hmox1 genes were markedly up-regulated. Other expression profiles in BALB/c Fech(m1Pas) mice identified roles for oxidative mechanisms in liver injury while modulated gene expression of hepatocyte transport proteins and cholesterol and bile acid synthesis illustrated the development of cholestasis. Subsequent inflammation and cirrhosis were also shown by the up-regulation of cytokine, cell cycling, and procollagen genes. Thus, gene expression profiles studied in Fech(m1Pas) mice may provide candidates for human polymorphisms that explain the sporadic hepatic consequences of erythropoietic protoporphyria.

Background: Patients with basal cell carcinoma (BCC) frequently develop further tumors during follow-up., Objective: We sought to elucidate the relative effects of pattern of ultraviolet radiation exposure, and site and histologic type of the first tumor, on the rate of increase in BCC numbers., Methods: We used negative binomial regression analysis to study the association of selected variables on the rate of increase in BCC numbers in 266 Caucasian patients who first presented with a tumor on the head/neck or trunk with nodular or superficial histology., Results: Patients with an initial truncal BCC with superficial histology demonstrated significantly faster increases in BCC numbers than did patients with other site and histology combinations., Conclusions: These data indicate that site and histology define subsets of patients with BCC.

Tamoxifen is contraindicated during pregnancy but many births have been reported in breast cancer patients taking this drug and numbers might be expected to increase with FDA approval of tamoxifen for risk reduction in women at high, risk of breast cancer. The neonatal mouse, exquisitely sensitive to xenobiotic estrogens, has been used to investigate the effects of short-term oral dosing with tamoxifen (1 mg/kg on days 2-5 after birth) on long-term changes in uterine pathology and gene expression. Increased adenomyosis incidence and severity was evident in the tamoxifen-treated mice with increasing age. Uterine weights in treated mice remained lower than the corresponding controls up until 9 months, after which they became greater but during life-time studies (up to 36 months), there was no development of uterine tumours. Pathological examination of uterine tissues showed there to be extensive down-growth of endometrial glands and stroma into thickened, abnormal myometrium that had disorganised fascicles of smooth muscle and increased interstitial collagen deposition. In advanced cases, the endometrial epithelium showed mild degrees of focal hyperplasia and squamous metaplasia but no atypical cytology suggestive of premalignant change. Microarray analysis of uterine RNA taken at 1.5, 3, 6, 9 and 12 months showed from 4500 ESTs, only 12 genes were continuously over-expressed by tamoxifen treatment over this time, while none was continuously down-regulated. Up-regulated genes include those for nerve growth factor (Ngfa), cathepsin B (Ctsb), transforming growth factor beta induced (Tqfbi) and collagens (Colla1, Colla2). Results provide a basis for understanding the mechanism for tamoxifen induced tissue remodelling and the development of adenomyosis.

Background: Caucasian renal transplant recipients living in Queensland, Australia, have the highest risk of nonmelanoma skin cancer in the world., Objective: To determine clinical and environmental factors associated with posttransplantation nonmelanoma skin cancer in Queensland., Methods: 361 Caucasian adult recipients completed a structured interview and full skin examination. Skin cancer details were obtained from hospital records., Results: Squamous cell carcinoma was strongly associated with blue or hazel eyes, time resident in a hot climate, and pretransplantation squamous cell carcinoma; tumor numbers were associated with birth in a hot climate, childhood sunburn, pretransplantation actinic keratoses, and smoking. The risk of basal cell carcinoma was strongly associated with acute or intermittent sun exposure during childhood and pretransplantation basal cell carcinoma; numbers were associated with blue or hazel eyes, time spent living in a hot climate, and male gender., Conclusion: Clinical and environmental factors can be used to identify recipients at risk of nonmelanoma skin cancer in Queensland.

Mutation rates at two expanded simple tandem repeat (ESTR) loci were studied in the germline of male mice exposed to two monofunctional alkylating agents, ethylnitrosourea (ENU) and isopropyl methanesulfonate (iPMS), and a topoisomerase II inhibitor, etoposide. Pre-meiotic exposure to the alkylating agents resulted in a highly significant increase in ESTR mutation rate, but did not alter post-meiotically exposed cells. Pre-meiotic mutation induction by ENU and iPMS was linear within the interval of doses from 12.5 to 25mg/kg and reached a plateau at higher concentrations. Paternal exposure to etoposide resulted in ESTR mutation induction at meiotic stages but did not affect post- or pre-meiotic cells. The pattern of ESTR mutation induction after pre-meiotic and meiotic exposure to chemical mutagens was similar to that previously obtained by various traditional approaches for monitoring germline mutation in mice. The results of this study show that ESTR loci provide a new efficient experimental system for monitoring the genetic effects of chemical mutagens, capable of detecting increases in mutation rates at low doses of exposure.

Several forms of cytochrome P450 (CYP) appear to metabolize principally pharmaceutical agents, as well as other dietary and plant chemicals. Other CYP forms have major roles in steroid, sterol, and bile acid metabolism. CYP1A2 expression is constitutively high in mouse liver and is well known for metabolizing several drugs and many procarcinogens to reactive intermediates that can cause toxicity or cancer. CYP1A2 is also known to carry out several endogenous functions such as uroporphyrinogen and melatonin oxidation and the 2- and 4-hydroxylations of estradiol. We have used cDNA microarray analysis of the untreated Cyp1a2(-/-) knockout mouse to search for changes in gene expression that might indicate important intrinsic roles for this enzyme. For 15 of the up- or downregulated genes, these increases or decreases were corroborated by reverse-transcription real-time polymerase chain reaction. Other than upregulation of the Hprt gene (used in the selection procedure for disrupting the Cyp1a2 gene), we found several genes upregulated that are associated with cell-cycle regulation and lipid metabolism. Besides Cyp1a2, the gene exhibiting the greatest downregulation was Igfbp1 (insulin-like growth factor binding protein-1), showing only 12% expression of that in the Cyp1a2(+/+) wild-type liver. Recurrent themes between both up- and downregulated genes include cell-cycle control, insulin action, lipogenesis, and fatty acid and cholesterol biosynthetic pathways. Histologically, the Cyp1a2(-/-) mouse exhibited an approximately 50% decrease in lipid stored in hepatocytes, and 50% increase in lipid present in interstitial fat-storing cells compared with that in the Cyp1a2(+/+) wild-type. These data suggest that the CYP1A2 enzyme might perform additional hepatic endogenous functions heretofore not appreciated.

Erythropoietic protoporphyria patients can develop cholestasis, severe hepatic damage, fibrosis, and cirrhosis. We modeled this hepatic pathology in C57BL/6J and BALB/c mice using griseofulvin and analyzed 3,127 genes for alteration of expression in the liver before and during the onset of protoporphyria, cholestasis, inflammation, and hepatic fibrosis. The two mouse strains developed different levels of pathologic damage in response to the griseofulvin. Characteristic gene expression profiles could be associated with griseofulvin-induced gene expression, disruption of lipid metabolism, and the pathologic states of inflammation, early fibrosis, and cholestasis. Additionally, some genes individually indicated an alteration of homeostasis. or pathologic state; for example, fibroblast proliferation was potentially indicated by increased calcyclin (SA100a6) expression. Changes in cytochrome P450 (Cyp) gene expression were particularly pronounced, with increased expression of the Cyp2a, Cyp2b, and Cyp3a families. Decreased Cyp4a10 and Cyp4a14 expression was observed that could be associated with early pathologic change. A potential decrease in bile acid and steroid biosynthesis was indicated by the decreased expression of Cyp7b1 and Hsd3b4, respectively. DNA damage was indicated by induction of GADD45. This study illustrates how transcriptional programs can be associated with different stimuli in the same experiment. The time course of change in the gene expression profile compared with changes in pathology and clinical chemistry shows the potential of this approach for modeling causative, predictive, and adaptive changes in gene expression during pathologic change.

Ecteinascidin-743 (ET-743) is a novel marine-derived anticancer drug with clinical activity in soft tissue sarcoma and ovarian cancer. Reversible transaminitis and subclinical cholangitis have frequently been described in patients who receive ET-743. To facilitate understanding of this adverse effect and help design suitable therapeutic rescue strategies, we characterized the hepatic effects of ET-743 in rats. Female rats received ET-743 (single dose, 40 microg/kg) i.v., and liver changes were assessed from 6 h up to 3 months after dosing by histopathology, immunohistochemistry, electron microscopy, hepatic and plasma biochemistry, and DNA microarray analysis. At 24 h posttreatment and beyond, livers displayed degeneration and patchy focal necrosis of bile duct epithelial cells associated with mild inflammation followed by fibrosis. Sporadic and focal zones of hepatic necrosis and hemorrhage were observed from day 2 onward, although the majority of hepatocytes appeared normal as judged by electron microscopy. Pathological alterations persisted up to 3 months after dosing. Plasma levels of total bilirubin were elevated up to 7-fold over those in untreated rats from day 2 onward and returned to control values by day 24. Activities of alkaline phosphatase and aspartate aminotransferase in plasma were elevated for 2 and 3 months, respectively. Activities of the hepatic microsomal drug-metabolizing enzymes cytochrome P-450 A1/2, CYP2E1, and CYP3A2 were decreased. DNA microarray analysis of livers from ET-743-treated animals showed a dramatic increase in the expression of ATP binding cassette transport genes Abcb1a and Abcb1b, which impart resistance to anticancer drugs, and of Cdc2a and Ccnd1, the rodent homologues of human cell cycle genes CDC2 and cyclin D1, respectively. The cell cycle gene expression changes mirrored ET-743-induced increases in liver weight and Ki-67 labeling of liver nuclei. The results suggest that the toxicity exerted by ET-743 in the rat liver is a consequence of biliary rather than hepatocellular damage and that it is accompanied by a wave of mitogenic activity, which may be driven by the transcriptional increase in Cdc2a expression.