Geographic variation of mutagenic exposures in kidney cancer genomes

International differences in the incidence of many cancer types indicate the existence of carcinogen exposures that have not yet been identified by conventional epidemiology make a substantial contribution to cancer burden1. In clear cell renal cell carcinoma, obesity, hypertension and tobacco smoking are risk factors, but they do not explain the geographical variation in its incidence2. Underlying causes can be inferred by sequencing the genomes of cancers from populations with different incidence rates and detecting differences in patterns of somatic mutations. Here we sequenced 962 clear cell renal cell carcinomas from 11 countries with varying incidence. The somatic mutation profiles differed between countries. In Romania, Serbia and Thailand, mutational signatures characteristic of aristolochic acid compounds were present in most cases, but these were rare elsewhere. In Japan, a mutational signature of unknown cause was found in more than 70% of cases but in less than 2% elsewhere. A further mutational signature of unknown cause was ubiquitous but exhibited higher mutation loads in countries with higher incidence rates of kidney cancer. Known signatures of tobacco smoking correlated with tobacco consumption, but no signature was associated with obesity or hypertension, suggesting that non-mutagenic mechanisms of action underlie these risk factors. The results of this study indicate the existence of multiple, geographically variable, mutagenic exposures that potentially affect tens of millions of people and illustrate the opportunities for new insights into cancer causation through large-scale global cancer genomics.

The Complexity of Tobacco Smoke-Induced Mutagenesis in Head and Neck Cancer

Tobacco smoke, alone or combined with alcohol, is the predominant cause of head and neck cancer (HNC). Here, we further explore how tobacco exposure contributes to cancer development by mutational signature analysis of 265 whole-genome sequenced HNC from eight countries. Six tobacco-associated mutational signatures were detected, including some not previously reported. Differences in HNC incidence between countries corresponded with differences in mutation burdens of tobacco-associated signatures, consistent with the dominant role of tobacco in HNC causation. Differences were found in the burden of tobacco-associated signatures between anatomical subsites, suggesting that tissue-specific factors modulate mutagenesis. We identified an association between tobacco smoking and three additional alcohol-related signatures indicating synergism between the two exposures. Tobacco smoking was associated with differences in the mutational spectra and repertoire of driver mutations in cancer genes, and in patterns of copy number change. Together, the results demonstrate the multiple pathways by which tobacco smoke can influence the evolution of cancer cell clones.

The Mutographs biorepository: A unique genomic resource to study cancer around the world

Large-scale biorepositories and databases are essential to generate equitable, effective, and sustainable advances in cancer prevention, early detection, cancer therapy, cancer care, and surveillance. The Mutographs project has created a large genomic dataset and biorepository of over 7,800 cancer cases from 30 countries across five continents with extensive demographic, lifestyle, environmental, and clinical information. Whole-genome sequencing is being finalized for over 4,000 cases, with the primary goal of understanding the causes of cancer at eight anatomic sites. Genomic, exposure, and clinical data will be publicly available through the International Cancer Genome Consortium Accelerating Research in Genomic Oncology platform. The Mutographs sample and metadata biorepository constitutes a legacy resource for new projects and collaborations aiming to increase our current research efforts in cancer genomic epidemiology globally.

Assigning mutational signatures to individual samples and individual somatic mutations with SigProfilerAssignment

MOTIVATION

Analysis of mutational signatures is a powerful approach for understanding the mutagenic processes that have shaped the evolution of a cancer genome. To evaluate the mutational signatures operative in a cancer genome, one first needs to quantify their activities by estimating the number of mutations imprinted by each signature.

RESULTS

Here we present SigProfilerAssignment, a desktop and an online computational framework for assigning all types of mutational signatures to individual samples. SigProfilerAssignment is the first tool that allows both analysis of copy-number signatures and probabilistic assignment of signatures to individual somatic mutations. As its computational engine, the tool uses a custom implementation of the forward stagewise algorithm for sparse regression and nonnegative least squares for numerical optimization. Analysis of 2700 synthetic cancer genomes with and without noise demonstrates that SigProfilerAssignment outperforms four commonly used approaches for assigning mutational signatures.

AVAILABILITY AND IMPLEMENTATION

SigProfilerAssignment is available under the BSD 2-clause license at https://github.com/AlexandrovLab/SigProfilerAssignment with a web implementation at https://cancer.sanger.ac.uk/signatures/assignment/.

Assigning mutational signatures to individual samples and individual somatic mutations with SigProfilerAssignment

Analysis of mutational signatures is a powerful approach for understanding the mutagenic processes that have shaped the evolution of a cancer genome. Here we present SigProfilerAssignment, a desktop and an online computational framework for assigning all types of mutational signatures to individual samples. SigProfilerAssignment is the first tool that allows both analysis of copy-number signatures and probabilistic assignment of signatures to individual somatic mutations. As its computational engine, the tool uses a custom implementation of the forward stagewise algorithm for sparse regression and nonnegative least squares for numerical optimization. Analysis of 2,700 synthetic cancer genomes with and without noise demonstrates that SigProfilerAssignment outperforms four commonly used approaches for assigning mutational signatures. SigProfilerAssignment is freely available at https://github.com/AlexandrovLab/SigProfilerAssignment with a web implementation at https://cancer.sanger.ac.uk/signatures/assignment/.

Visions of recovery: a cross-diagnostic examination of eating disorder pro-recovery communities on TikTok

Individuals seeking support or inspiration for eating disorder recovery may turn to pro-recovery content on social media sites such as TikTok. While research has thus far treated pro-recovery social media as a fairly homogeneous space, many pro-recovery hashtags single out particular eating disorder diagnoses. This exploratory study used codebook thematic analysis of 241 popular pro-recovery videos on TikTok to compare the presentation of eating disorders and eating disorder recovery across five different diagnosis-specific hashtags: #anarecovery, #arfidrecovery, #bedrecovery, #miarecovery, and #orthorexiarecovery. These hashtags refer to the following eating disorder diagnoses respectively: anorexia nervosa, avoidant restrictive food intake disorder, binge eating disorder, bulimia nervosa, and orthorexia nervosa. Our analysis generated the following qualitative themes across the entire dataset: (1) centrality of food to eating disorders and recovery, (2) what eating disorders look and feel like, (3) recovery as a process, (4) getting and giving help, and (5) negotiating diet culture in recovery. To supplement our qualitative findings and facilitate cross-diagnostic comparisons, we also conducted one-way ANOVAs and chi-square tests to probe for statistically significant differences in audience engagement and code prevalence across the different hashtags. Our results indicate that there are clear differences in how recovery is envisioned on TikTok based on which diagnostic hashtags are employed. Such variations in how different eating disorders are imagined on popular social media demand further investigation and clinical consideration.

An international report on bacterial communities in esophageal squamous cell carcinoma

The incidence of esophageal squamous cell carcinoma (ESCC) is disproportionately high in the eastern corridor of Africa and parts of Asia. Emerging research has identified a potential association between poor oral health and ESCC. One possible link between poor oral health and ESCC involves the alteration of the microbiome. We performed an integrated analysis of four independent sequencing efforts of ESCC tumors from patients from high- and low-incidence regions of the world. Using whole genome sequencing (WGS) and RNA sequencing (RNAseq) of ESCC tumors from 61 patients in Tanzania, we identified a community of bacteria, including members of the genera Fusobacterium, Selenomonas, Prevotella, Streptococcus, Porphyromonas, Veillonella and Campylobacter, present at high abundance in ESCC tumors. We then characterized the microbiome of 238 ESCC tumor specimens collected in two additional independent sequencing efforts consisting of patients from other high-ESCC incidence regions (Tanzania, Malawi, Kenya, Iran, China). This analysis revealed similar ESCC-associated bacterial communities in these cancers. Because these genera are traditionally considered members of the oral microbiota, we next explored whether there was a relationship between the synchronous saliva and tumor microbiomes of ESCC patients in Tanzania. Comparative analyses revealed that paired saliva and tumor microbiomes were significantly similar with a specific enrichment of Fusobacterium and Prevotella in the tumor microbiome. Together, these data indicate that cancer-associated oral bacteria are associated with ESCC tumors at the time of diagnosis and support a model in which oral bacteria are present in high abundance in both saliva and tumors of some ESCC patients.

Uncovering novel mutational signatures by de novo extraction with SigProfilerExtractor

Mutational signature analysis is commonly performed in cancer genomic studies. Here, we present SigProfilerExtractor, an automated tool for de novo extraction of mutational signatures, and benchmark it against another 13 bioinformatics tools by using 34 scenarios encompassing 2,500 simulated signatures found in 60,000 synthetic genomes and 20,000 synthetic exomes. For simulations with 5% noise, reflecting high-quality datasets, SigProfilerExtractor outperforms other approaches by elucidating between 20% and 50% more true-positive signatures while yielding 5-fold less false-positive signatures. Applying SigProfilerExtractor to 4,643 whole-genome- and 19,184 whole-exome-sequenced cancers reveals four novel signatures. Two of the signatures are confirmed in independent cohorts, and one of these signatures is associated with tobacco smoking. In summary, this report provides a reference tool for analysis of mutational signatures, a comprehensive benchmarking of bioinformatics tools for extracting signatures, and several novel mutational signatures, including one putatively attributed to direct tobacco smoking mutagenesis in bladder tissues.

Mutational signatures in esophageal squamous cell carcinoma from eight countries with varying incidence

Esophageal squamous cell carcinoma (ESCC) shows remarkable variation in incidence that is not fully explained by known lifestyle and environmental risk factors. It has been speculated that an unknown exogenous exposure(s) could be responsible. Here we combine the fields of mutational signature analysis with cancer epidemiology to study 552 ESCC genomes from eight countries with varying incidence rates. Mutational profiles were similar across all countries studied. Associations between specific mutational signatures and ESCC risk factors were identified for tobacco, alcohol, opium and germline variants, with modest impacts on mutation burden. We find no evidence of a mutational signature indicative of an exogenous exposure capable of explaining differences in ESCC incidence. Apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like (APOBEC)-associated mutational signatures single-base substitution (SBS)2 and SBS13 were present in 88% and 91% of cases, respectively, and accounted for 25% of the mutation burden on average, indicating that APOBEC activation is a crucial step in ESCC tumor development.

Does Perpetrator Occupation Affect Classification of Sexual Assault?

Classification of sexual assault varies based on the characteristics of the victim, perpetrator, and event. However, most studies focus on the individual characteristics of participants asked to classify the assault, the victims' characteristics, or the event; few have examined variations in the perpetrator. Therefore, this study examined whether the occupation of the perpetrator affected the classification of the event as sexual assault. Participants included a primarily White female sample of undergraduate students (n = 401) at a south-Atlantic university. They completed a paper-and-pencil survey containing an ambiguous sexual assault encounter where the occupation of the perpetrator (athlete, reporter, college student, or politician) was randomly varied. Participants were asked to classify whether the encounter was sexual assault and what an appropriate punishment might be. Additional measures included the Illinois Rape Myth Acceptance Scale (IRMA) and questions about personal experience with sexual assault. Overall, most participants labeled the encounter as sexual assault, indicating that college students are aware of the legal parameters for providing consent. However, this classification occurred differentially based on the occupation of the perpetrator. Participants were most likely to label the athlete as committing sexual assault, followed by the college student, politician, and reporter, respectively. Females and those who reject rape myths were more likely to label the scenario as sexual assault. A "personal apology" and a "sexual rehabilitation program" were the most common punishments selected for the perpetrator. These findings highlight potential concerns and the need for additional training when college students adjudicate sexual assault reports and determine appropriate consequences.

Cannabis, Cannabidiol Oils and Tetrahydrocannabinol-What Do Veterinarians Need to Know?

As cannabis-derived products have become more available, veterinarians are seeing more cases of toxicosis. In addition, animal owners are having an increasing interest in using these products for their pets. This review looks at the situation in Europe and North America, the different types of cannabis and cannabis-derived products with historical examples of use in animals, and the cannabis industry. The existing regulatory framework for use in humans and animals as medicines and/or supplements was examined. Finally, a review of the clinical indications for which medicinal cannabis is authorised, a discussion of toxicosis, and recommendations and warnings around medical cannabis use are presented.

Mutagenicity of 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP) in human TP53 knock-in (Hupki) mouse embryo fibroblasts

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a possible human carcinogen formed in cooked fish and meat. PhIP is bioactivated by cytochrome P450 enzymes to form 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP), a genotoxic metabolite that reacts with DNA leading to the mutation-prone DNA adduct N-(deoxyguanosin-8-yl)-PhIP (dG-C8-PhIP). Here, we studied N-OH-PhIP-induced whole genome mutagenesis in human TP53 knock-in (Hupki) mouse embryo fibroblasts (HUFs) immortalised and subjected to whole genome sequencing (WGS). In addition, mutagenicity of N-OH-PhIP in TP53 and the lacZ reporter gene were assessed. TP53 mutant frequency in HUF cultures treated with N-OH-PhIP (2.5 μM for 24 h, n = 90) was 10% while no TP53 mutations were found in untreated controls (DMSO for 24 h, n = 6). All N-OH-PhIP-induced TP53 mutations occurred at G:C base pairs with G > T/C > A transversions accounting for 58% of them. TP53 mutations characteristic of those induced by N-OH-PhIP have been found in human tumours including breast and colorectal, which are cancer types that have been associated with PhIP exposure. LacZ mutant frequency increased 25-fold at 5 μM N-OH-PHIP and up to ~350 dG-C8-PhIP adducts/10⁸ nucleosides were detected by ultra-performance liquid chromatography-electrospray ionisation multistage scan mass spectrometry (UPLC-ESI-MS³) at this concentration. In addition, a WGS mutational signature defined by G > T/C > A transversions was present in N-OH-PhIP-treated immortalised clones, which showed similarity to COSMIC SBS4, 18 and 29 signatures found in human tumours.

Mutagenicity of acrylamide and glycidamide in human TP53 knock-in (Hupki) mouse embryo fibroblasts

Acrylamide is a suspected human carcinogen formed during high-temperature cooking of starch-rich foods. It is metabolised by cytochrome P450 2E1 to its reactive metabolite glycidamide, which forms pre-mutagenic DNA adducts. Using the human TP53 knock-in (Hupki) mouse embryo fibroblasts (HUFs) immortalisation assay (HIMA), acrylamide- and glycidamide-induced mutagenesis was studied in the tumour suppressor gene TP53. Selected immortalised HUF clones were also subjected to next-generation sequencing to determine mutations across the whole genome. The TP53-mutant frequency after glycidamide exposure (1.1 mM for 24 h, n = 198) was 9% compared with 0% in cultures treated with acrylamide [1.5 (n = 24) or 3 mM (n = 6) for 48 h] and untreated vehicle (water) controls (n = 36). Most glycidamide-induced mutations occurred at adenines with A > T/T > A and A > G/T > C mutations being the most common types. Mutations induced by glycidamide occurred at specific TP53 codons that have also been found to be mutated in human tumours (i.e., breast, ovary, colorectal, and lung) previously associated with acrylamide exposure. The spectrum of TP53 mutations was further reflected by the mutations detected by whole-genome sequencing (WGS) and a distinct WGS mutational signature was found in HUF clones treated with glycidamide that was again characterised by A > G/T > C and A > T/T > A mutations. The WGS mutational signature showed similarities with COSMIC mutational signatures SBS3 and 25 previously found in human tumours (e.g., breast and ovary), while the adenine component was similar to COSMIC SBS4 found mostly in smokers’ lung cancer. In contrast, in acrylamide-treated HUF clones, only culture-related background WGS mutational signatures were observed. In summary, the results of the present study suggest that glycidamide may be involved in the development of breast, ovarian, and lung cancer.

The mutational landscape of normal human endometrial epithelium

All normal somatic cells are thought to acquire mutations, but understanding of the rates, patterns, causes and consequences of somatic mutations in normal cells is limited. The uterine endometrium adopts multiple physiological states over a lifetime and is lined by a gland-forming epithelium1,2. Here, using whole-genome sequencing, we show that normal human endometrial glands are clonal cell populations with total mutation burdens that increase at about 29 base substitutions per year and that are many-fold lower than those of endometrial cancers. Normal endometrial glands frequently carry 'driver' mutations in cancer genes, the burden of which increases with age and decreases with parity. Cell clones with drivers often originate during the first decades of life and subsequently progressively colonize the epithelial lining of the endometrium. Our results show that mutational landscapes differ markedly between normal tissues-perhaps shaped by differences in their structure and physiology-and indicate that the procession of neoplastic change that leads to endometrial cancer is initiated early in life.

Novel GPR34 and CCR6 mutation and distinct genetic profiles in MALT lymphomas of different sites

Mucosa-associated lymphoid tissue (MALT) lymphoma originates from a background of diverse chronic inflammatory disorders at various anatomic sites. The genetics underlying its development, particularly in those associated with autoimmune disorders, is poorly characterized. By whole exome sequencing of 21 cases of MALT lymphomas of the salivary gland and thyroid, we have identified recurrent somatic mutations in 2 G-protein coupled receptors (GPR34 and CCR6) not previously reported in human malignancies, 3 genes (PIK3CD, TET2, TNFRSF14) not previously implicated in MALT lymphoma, and a further 2 genes (TBL1XR1, NOTCH1) recently described in MALT lymphoma. The majority of mutations in GPR34 and CCR6 were nonsense and frameshift changes clustered in the C-terminal cytoplasmic tail, and would result in truncated proteins that lack the phosphorylation motif important for β-arrestin-mediated receptor desensitization and internalization. Screening of these newly identified mutations, together with previously defined genetic changes, revealed distinct mutation profiles in MALT lymphoma of various sites, with those of salivary gland characterized by frequent TBL1XR1 and GPR34 mutations, thyroid by frequent TET2, TNFRSF14 and PIK3CD mutations, and ocular adnexa by frequent TNFAIP3 mutation. Interestingly, in MALT lymphoma of the salivary gland, there was a significant positive association between TBL1XR1 mutation and GPR34 mutation/translocation (P=0.0002). In those of ocular adnexa, TBL1XR1 mutation was mutually exclusive from TNFAIP3 mutation (P=0.049), but significantly associated with IGHV3-23 usage (P=0.03) and PIK3CD mutation (P=0.009). These findings unravel novel insights into the molecular mechanisms of MALT lymphoma and provide further evidence for potential oncogenic co-operation between receptor signaling and genetic changes.

Somatic Mutation Screening Using Archival Formalin-Fixed, Paraffin-Embedded Tissues by Fluidigm Multiplex PCR and Illumina Sequencing

High-throughput somatic mutation screening using FFPE tissues is a major challenge because of a lack of established methods and validated variant calling algorithms. We aimed to develop a targeted sequencing protocol by Fluidigm multiplex PCR and Illumina sequencing and to establish a companion variant calling algorithm. The experimental protocol and variant calling algorithm were first developed and optimized against a series of somatic mutations (147 substitutions, 12 indels ranging from 1 to 33 bp) in seven genes, previously detected by Sanger sequencing of DNA from 163 FFPE lymphoma biopsy specimens. The optimized experimental protocol and variant calling algorithm were further ascertained in two separate experiments by including the seven genes as a part of larger gene panels (22 or 13 genes) using FFPE and high-molecular-weight lymphoma DNAs, respectively. We found that most false-positive variants were due to DNA degradation, deamination, and Taq polymerase errors, but they were nonreproducible and could be efficiently eliminated by duplicate experiments. A small fraction of false-positive variants appeared in duplicate, but they were at low alternative allele frequencies and could be separated from mutations when appropriate threshold value was used. In conclusion, we established a robust practical approach for high-throughput mutation screening using archival FFPE tissues.

Prepubertal mouse testis growth and maturation and androgen production are acutely sensitive to di-n-butyl phthalate

Phthalates are plasticizers with widespread industrial, domestic, and medical applications. Epidemiological data indicating increased incidence of testicular dysgenesis in boys exposed to phthalates in utero are reinforced by studies demonstrating that phthalates impair fetal rodent testis development. Because humans are exposed to phthalates continuously from gestation through adulthood, it is imperative to understand what threat phthalates pose at other life stages. To determine the impact during prepuberty, we assessed the consequences of oral administration of 1 to 500 mg di-n-butyl phthalate (DBP)/kg/d in corn oil to wild-type (C57BL/6J) male mice from 4 to 14 days of age. Dose-dependent effects on testis growth correlated with reduced Sertoli cell proliferation. Histological and immunohistochemical analyses identified delayed spermatogenesis and impaired Sertoli cell maturation after exposure to 10 to 500 mg DBP/kg/d. Interference with the hypothalamic-pituitary-gonadal axis was indicated in mice fed 500 mg DBP/kg/d, which had elevated circulating inhibin but no change in serum FSH. Increased immunohistochemical staining for inhibin-α was apparent at doses of 10 to 500 mg DBP/kg/d. Serum testosterone and testicular androgen activity were lower in the 500 mg DBP/kg/d group; however, reduced anogenital distance in all DBP-treated mice suggested impaired androgen action at earlier time points. Long-term effects were evident, with smaller anogenital distance and indications of disrupted spermatogenesis in adult mice exposed prepubertally to doses from 1 mg DBP/kg/d. These data demonstrate the acute sensitivity of the prepubertal mouse testis to DBP at doses 50- to 500-fold lower than those used in rat and identify the upregulation of inhibin as a potential mechanism of DBP action.

Learning preferences and learning styles: a study of Wessex general practice registrars

BACKGROUND

Experienced trainers know that individual registrars react very differently to identical learning experiences generated during the year in practice. This divergence reflects differences in registrars' learning styles. Only one study of United Kingdom (UK) general practitioners' learning styles has been undertaken. Learning style theory predicts that matching learning preference with learning style will enhance learning. This paper researches for the first time the evidence in the setting of UK general practice.

AIM

To determine, for the general practice registrars within the Wessex Region, the nature of their learning preferences and learning styles and correlations between them.

DESIGN OF STUDY

A descriptive confidential postal questionnaire survey.

SETTING

Fifty-seven registrars identified in the Wessex Region with a minimum experience of six months in general practice.

METHOD

The questionnaire gathered demographic data (sex, age, experience in general practice, years post-registration, and postgraduate qualifications). Learning preferences were elicited using a six-point Likert scale for learning experiences. The Honey and Mumford Learning Style Questionnaire (LSQ) elicited the registrars' learning styles. A second questionnaire was sent to non-responders.

RESULTS

The response rate was 74%. Registrars report that interactive learning with feedback is preferred, but more passive learning formats remain valued. A wide range of learning style scores was found. The Honey and Mumford LSQ mean scores fell within the reflector-theorist quadrant. Evidence for correlations between learning preferences and learning styles was also found, in particular for the multiple choice question and audit components of summative assessment.

CONCLUSION

A wide range of registrar learning styles exists in Wessex, and initial correlations are described between learning preferences and learning styles as predicted by style theory. This work sets the stage for a shared understanding and use of learning style theory to enhance professional learning throughout a GP's career. More research is needed in this domain.

Cloning and characterization of a secreted frizzled-related protein that is expressed by the retinal pigment epithelium

The Wnt/frizzled cell signaling pathway has been implicated in the determination of polarity in a number of systems, including the Drosophila retina. The vertebrate retina develops from an undifferentiated neuroepithelium into an organized and laminated structure that demonstrates a high degree of polarity at both the tissue and cellular levels. In the process of searching for molecules that are preferentially expressed by the vertebrate retinal pigment epithelium (RPE), we identified secreted frizzled-related protein 5 (SFRP5), a member of the SFRP family that appears to act by modulating Wnt signal transduction. SFRP5 is highly expressed by RPE cells, and is also expressed in the pancreas. Within the retina, the related molecule SFRP2 is expressed specifically by cells of the inner nuclear layer. Thus, photoreceptors are likely to be bathed by two opposing gradients of SFRP molecules. Consistent with SFRP5 's postulated role in modulating Wnt signaling in the retina, it inhibits the ability of Xwnt-8 mRNA to induce axis duplication in Xenopus embryos. The human SFRP5 gene consists of three coding exons and it maps to chromosome 10q24.1; human SFRP2 maps to 4q31.3. Based on the biology and complementary expression patterns of SFRP2 and SFRP5, we suggest that they may be involved in determining the polarity of photoreceptor, and perhaps other, cells in the retina.

Identification of significant variation in the composition of lipophosphoglycan-like molecules of E. histolytica and E. dispar

The lipophosphoglycan-like (LPG-like) molecules of E. histolytica virulent strains are clearly distinct from those of the avirulent E. histolytica and E. dispar strains. Abundant 'LPG' levels are apparently limited to virulent strains, while lipophosphopeptidoglycans ('LPPG's) are common to both virulent and avirulent strains of E. histolytica and E. dispar. It is therefore conceivable that 'LPPG' performs a function that is essential to survival within the host, while the 'LPG' performs a more specific function related to virulence.

Virulent and avirulent Entamoeba histolytica and E. dispar differ in their cell surface phosphorylated glycolipids

Virulent strains of Entamoeba histolytica have been reported to produce a mixture of phosphoglycoconjugates that share some structural features with the lipophosphoglycans (LPGs) of Leishmania. Purification of these glycoconjugates is essential to their precise structural characterization. In this study we have extracted 'LPG-like' molecules from various virulent E. histolytica strains and purified on the basis of charge differences, 2 apparently related glycoconjugates a 'LPG' and a 'lipophosphopeptidoglycan (LPPG)'. In marked contrast to the abundance of these 'LPG' and 'LPPG' molecules in the virulent strains, avirulent E. histolytica and E. dispar strains produce either very low, or no detectable levels of LPG, and either low levels or modified forms of 'LPPG'. Monospecific polyclonal antibodies prepared against that 'LPG' of the virulent strain HM-1:1MSS c16 identified epitopes shared between both the 'LPG' and the 'LPPG' of this and other virulent strains, using Western blot analysis. Flow cytometric analysis of a range of strains using these antibodies identified a surface distribution of these molecules and confirmed a correlation between surface exposure of epitopes bound by these antibodies and parasite virulence.

Studies of copper transport in cultured bovine chondrocytes

Copper serves as the cofactor for a number of important enzymes in cartilage, as well as in other tissues, including lysyl oxidase, superoxide dismutase, and cytochrome oxidase. Ceruloplasmin is responsible for the transport of approx. 95% of the copper in serum, but the mechanisms for intracellular copper transport are unknown. We have demonstrated recently that a high-molecular-weight cartilage glycoprotein, referred to as CMGP, has regions of sequence homology with ceruloplasmin. CMGP also binds copper and has at least some oxidase activity similar to that of ceruloplasmin. Other tissues synthesize intracellular ceruloplasmin-like proteins. The present report represents part of an effort to examine the hypothesis that CMGP is a copper transport protein in chondrocytes and to characterize the enzymatic activities of CMGP. These studies demonstrate that CMGP is the principal chondrocyte protein labeled by 67Cu in vitro and that the label is localized to the mitochondria, cytosol, and membrane fractions of sucrose gradients, suggesting copper transport through the cell. In parallel experiments, [3H]leucine was incorporated into proteins corresponding to the subunits and fragments of CMGP, as described previously, and in a similar distribution among the subcellular fractions as labeled copper. Additionally, CMGP has oxidase and ferroxidase activities similar to those of ceruloplasmin.

Recognizing and treating delirium in patients admitted to general hospitals

We report a retrospective study of 59 patients for whom our university hospital nursing service had required the use of lay sitters because of the need for constant observation. Of 54 charts examined, 28 noted a need for psychiatric consultation, mostly because of delirious states. Quality of care deficits discerned included (1) inadequate pharmacotherapy of alcoholic and nonalcoholic delirium, (2) inadequate search for treatable causes of delirium (thyroid, B12, and folate deficiencies), (3) insufficient awareness of persistent cognitive deficits, which influence the patient's ability to care for himself or give informed consent. The knowledge and skills deficits we found are not unique to this hospital and reflect the failure of most graduate programs to reinforce basic psychiatric teaching. The quality of care issues indicate that more serious consideration should be given to providing necessary psychiatric training.

Gross and microscopic anatomy of the vagal innervation of the rat heart

Intrinsic cardiac ganglia and their vagal innervation are described from gross and microscopic dissections and functional studies in the anesthetized, open-chest, adult rat. Dissecting microscope sketches of the ventral and dorsal aspects of the rat heart provide gross descriptions of the anatomical course of the vagal cardiac nerves. Histological sectioning of adipose tissue packets surrounding the terminal endings of vagal branches distributed to the roots of the great cardiac vessels (aorta, pulmonary artery, precaval veins) revealed clusters of autonomic ganglia. These packets or "fat pads" were located: (1) along the dorsal surface of the right precava and extending medially toward the aortic root, (2) deep to the aortic arch, (3) in the angle between the root of the left precava and the pulmonary artery on the superior-dorsal surface of the left atrium, and (4) in the rostro-dorsal interatrial septum. Vagal distributions of small terminal branches were traced to each of these pads, which contained numerous autonomic ganglia. Electrical excitation of right or left cervical vagus elicited varying degrees of sinus slowing, slowing of A-V conduction, and suppression in atrial contractile force. Very small quantities (0.5 mg in 10 microliters saline) of the ganglionic blocking agent, hexamethonium (C6) were injected selectively into a single fat pad, followed by repetition of right or left vagal stimulation, with careful analysis of changes in heart rate (paced and unpaced), A-V conduction, and contractile force.

The Moyer reading technique re-evaluated

The purpose of the study was to design treatment programmes for various types of reading disorder in such a way as to allow a valid evaluation of their efficacy, i.e. in a way which allows specific treatment effects to be distinguished from non-specific treatment effects (e.g., the effects of attention from a helpful person), and from changes unrelated to treatment (e.g. spontaneous recovery). In particular, the intention was to investigate whether specific forms of therapeutic intervention help specific forms of disorder. Studies on five patients with different patterns of reading difficulty showed that specific treatment programmes were responsible for significant improvement in the patients' reading performance.

Chronic monitoring of intracranial pressure using an in vivo calibrating sensor: experience in patients with pseudotumor cerebri

A number of reliable methods are available for the short term monitoring of intracranial pressure (ICP). However, the danger of infection and the need for external connections make the use of these methods for extended periods inappropriate. Most previously described devices for chronic monitoring of ICP are of limited value because of uncertain drift from zero-point readings. The Hittman-Meyer ICP sensor approaches the ideal for a long term monitoring device. It is fully implantable and is accurate over a wide range of pressures and for extended periods. It is designed so that in vivo calibration may be performed in a noninvasive fashion. We report the use of this device in eight patients with pseudomotor cerebri. It has functioned accurately for periods ranging up to 14 months after implantation and has proven to be a valuable aid in the management of these patients. (Neurosurgery, 5: 666-670, 1979).

Serial computerized tomographic scanning and the prognosis of severe head injury

Serial (two or three) computerized tomographic (CT) scans were performed on a series of 58 patients with severe head injury. The protocol called for scans to be done upon admission and on Days 3 and 7 after injury. New lesions (i.e., lesions not visualized on the initial CT scans but appearing on subsequent scans) were a frequent finding, occurring in over half of all patients. For the purposes of this study a new lesion was classified as edema involving two or more lobes, extra-axial hematoma, parenchymal hemorrhage, or infarction. Significant correlation was found between good outcome and the absence of new lesions and between bad outcome and the development of new lesions (p less than 0.001). Several patients did well in spite of the development of new lesions, but these patients were unique in that most had small, unilateral parenchymal hematomas located at or near the frontal or temporal poles. In most cases, patients who did poorly in spite of not developing new lesions had severe injuried visualized on their initial scans (massive intracerebral hematoma, hemorrhage of the corpus callosum) or succumbed to medical complications. The pertinent literature is reviewed, and other CT findings associated with a poor prognosis are noted. The authors suggest that serial CT scanning may be used to make prognostic assessments in severely head-injured patients and may be of value in increasing the confidence in and accuracy of assessments made on clinical grounds alone. (Neurosurgery, 5: 566--569, 1979).

Dexamethasone and severe head injury. A prospective double-blind study

A prospective double-blind study of the effects of dexamethasone administration on the outcome of patients with severe head injuries was performed. Patients were stratified for severity of neurological injury and were treated with placebo, low-dose dexamethasone (16 mg/day), or high-dose dexamethasone (96 mg/day) for a period of 6 days. Outcome was evaluated at 6 months following injury. Of the 76 patients available for analysis, a good outcome was achieved in 37% of placebo-treated patients, 44% of low-dose-treated patients, and 29% of high-dose-treated patients. These differences are not statistically significant. Similarly dexamethasone administration had no statistically significant effect on intracranial pressure patterns or serial neurological examinations during hospitalization. Gastrointestinal bleeding occurred in only one patient. Good outcome was associated with age under 10 years, lighter depth of coma on admission, and the preservation of brain-stem reflexes upon admission. A recalculation of data in previous clinical series purporting to show an improvement in outcome as a result of corticosteroid therapy shows no significant difference in outcome when steroid- and placebo-treated patients are compared. In our series, 90% of all deaths were caused by recurrent intracranial hematomas, medical complications, or diffuse brain injuries with parenchymal hemorrhage and tissue disruption -- causes of death which cannot be affected by corticosteroid therapy. The study suggests that dexamethasone in either high or low dosages has no significant effect on morbidity and mortality following severe head injury.

Neurodiagnostic studies and the management of head injury

The rational management of patients with head injury calls for the closest cooperation between the radiologist and neurosurgeon. Until the last three to four years, cerebral angiography had been considered the diagnostic procedure of choice for the management of patients with suspected traumatically induced intracranial mass lesions. Experience with CT scanning now indicates that for a number of reasons this procedure is to be preferred in the diagnosis of head injuries. It is more rapid than angiography, routinely visualizes the entire brain, is noninvasive, resolves lesions that are much smaller than any visualized by angiography and defines the density and thus the nature of traumatic lesions in a manner not possible with previously employed techniques. Using CT scanning in a sequential fashion we have routinely been able to visualize the appearance of new lesions in the post-traumatic period and have as well, been able to develop insights into the temporal appearance and disappearance of white matter edema as measured by Hounsfield numbers. In the late post-traumatic period, it has been valuable in defining hydrocephalus, porencephaly and other post-traumatic lesions that have a significant bearing on both therapy and prognosis.