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There is considerable evidence for mitochondrial-nuclear co-adaptation as a key evolutionary driver. Hypotheses regarding the roles of sex-linkage have emphasized Z-linked nuclear genes with mitochondrial function (N-mt genes), whereas it remains contentious whether the perfect co-inheritance of W genes with mitogenomes could hinder or facilitate co-adaptation. Young (neo-) sex chromosomes that possess relatively many N-mt genes compared to older chromosomes provide unprecedented hypothesis-testing opportunities. Eastern Yellow Robin (EYR) lineages in coastal and inland habitats with different climates are diverged in mitogenomes, and in a ~ 15.4 Mb nuclear region enriched with N-mt genes, in contrast with otherwise-similar nuclear genomes. This nuclear region maps to passerine chromosome 1A, previously found to be neo-sex in the inland EYR genome. To compare sex-linked Chr1A-derived genes between lineages, we assembled and annotated the coastal EYR genome. We found that: (i) the coastal lineage shares a similar neo-sex system with the inland lineage, (ii) neo-W and neo-Z N-mt genes are not more diverged between lineages than are comparable non-N-mt genes, and showed little evidence for broad positive selection, (iii) however, W-linked N-mt genes are more diverged between lineages than are their Z-linked gametologs. The latter effect was ~7 times stronger for N-mt than non-N-mt genes, suggesting that W-linked N-mt genes might have diverged between lineages under environmental selection through co-evolution with mitogenomes. Finally, we identify a candidate gene driver for divergent selection, NDUFA12. Our data represent a rare example suggesting a possible role for W-associated mitochondrial-nuclear interactions in climate-associated adaptation and lineage differentiation.

Background/AimsSupport vector machine-based automated grading (known as iGradingM) has been shown to be safe, cost-effective and robust in the diabetic retinopathy (DR) screening (DES) programme in Scotland. It triages screening episodes as gradable with no DR versus manual grading required. The study aim was to develop a deep learning-based autograder using images and gradings from DES and to compare its performance with that of iGradingM.MethodsRetinal images, quality assurance (QA) data and routine DR grades were obtained from national datasets in 179 944 patients for years 2006–2016. QA grades were available for 744 images. We developed a deep learning-based algorithm to detect whether either eye contained ungradable images or any DR. The sensitivity and specificity were evaluated against consensus QA grades and routine grades.ResultsImages used in QA which were ungradable or with DR were detected by deep learning with better specificity compared with manual graders (p<0.001) and with iGradingM (p<0.001) at the same sensitivities. Any DR according to the DES final grade was detected with 89.19% (270 392/303 154) sensitivity and 77.41% (500 945/647 158) specificity. Observable disease and referable disease were detected with sensitivities of 96.58% (16 613/17 201) and 98.48% (22 600/22 948), respectively. Overall, 43.84% of screening episodes would require manual grading.ConclusionA deep learning-based system for DR grading was evaluated in QA data and images from 11 years in 50% of people attending a national DR screening programme. The system could reduce the manual grading workload at the same sensitivity compared with the current automated grading system.

The ribosome is a large ribonucleoprotein assembly that uses diverse and complex molecular interactions to maintain proper folding. In vivo assembled ribosomes have been isolated using MS2 tags installed in either the 16S or 23S ribosomal RNAs (rRNAs), to enable studies of ribosome structure and function in vitro. RNA tags in the Escherichia coli50S subunit have commonly been inserted into an extended helix H98 in 23S rRNA, as this addition does not affect cellular growth or in vitro ribosome activity. Here, we find that E. coli50S subunits with MS2 tags inserted in H98 are destabilized compared to wild-type (WT) 50S subunits. We identify the loss of RNA–RNA tertiary contacts that bridge helices H1, H94, and H98 as the cause of destabilization. Using cryogenic electron microscopy (cryo-EM), we show that this interaction is disrupted by the addition of the MS2 tag and can be restored through the insertion of a single adenosine in the extended H98 helix. This work establishes ways to improve MS2 tags in the 50S subunit that maintain ribosome stability and investigates a complex RNA tertiary structure that may be important for stability in various bacterial ribosomes.

There is increasing interest in computer applications, using artificial intelligence methodologies, to perform health care tasks previously performed by humans, particularly in medical imaging for diagnosis. In stroke, there are now commercial artificial intelligence software for use with computed tomography or MR imaging to identify acute ischemic brain tissue pathology, arterial obstruction on computed tomography angiography or as hyperattenuated arteries on computed tomography, brain hemorrhage, or size of perfusion defects. A rapid, accurate diagnosis may aid treatment decisions for individual patients and could improve outcome if it leads to effective and safe treatment; or conversely, to disaster if a delayed or incorrect diagnosis results in inappropriate treatment. Despite this potential clinical impact, diagnostic tools including artificial intelligence methods are not subjected to the same clinical evaluation standards as are mandatory for drugs. Here, we provide an evidence-based review of the pros and cons of commercially available automated methods for medical imaging diagnosis, including those based on artificial intelligence, to diagnose acute brain pathology on computed tomography or magnetic resonance imaging in patients with stroke.

RNA thermosensors (RNATs), found in the 5′ untranslated region (UTR) of some bacterial messenger RNAs (mRNAs), control the translation of the downstream gene in a temperature-dependent manner. In Listeria monocytogenes, the expression of a key transcription factor, PrfA, is mediated by an RNAT in its 5′ UTR. PrfA functions as a master regulator of virulence in L. monocytogenes, controlling the expression of many virulence factors. The temperature-regulated expression of PrfA by its RNAT element serves as a signal of successful host invasion for the bacteria. Structurally, the prfA RNAT bears little resemblance to known families of RNATs, and prior studies demonstrated that the prfA RNAT is highly responsive over a narrow temperature range. Herein, we have undertaken a comprehensive mutational and thermodynamic analysis to ascertain the molecular determinants of temperature sensitivity. We provide evidence to support the idea that the prfA RNAT unfolding is different from that of cssA, a well-characterized RNAT, suggesting that these RNATs function via distinct mechanisms. Our data show that the unfolding of the prfA RNAT occurs in two distinct events and that the internal loops play an important role in mediating the cooperativity of RNAT unfolding. We further demonstrated that regions distal to the ribosome binding site (RBS) not only contribute to RNAT structural stability but also impact translation of the downstream message. Our collective results provide insight connecting the thermal stability of the prfA RNAT structure, unfolding energetics, and translational control.

Mutations in the common gamma chain of the interleukin 2 receptor (IL2RG) or the associated downstream signaling enzyme Janus kinase 3 (JAK3) genes are typically characterized by a T cell-negative, B cell-positive, natural killer (NK) cell-negative (T−B+NK−) severe combined immunodeficiency (SCID) immune phenotype. We report clinical course, immunological, genetic and proteomic work-up of two patients with different novel mutations in the IL-2-JAK3 pathway with a rare atypical presentation of T−B+NK−SCID. Lymphocyte subpopulation revealed significant T cells lymphopenia, normal B cells, and NK cells counts (T−B+NK+SCID). Despite the presence of B cells, IgG levels were low and IgA and IgM levels were undetectable. T-cell proliferation in response to mitogens in patient 1 was very low and T-cell receptor V-beta chain repertoire in patient 2 was polyclonal. Whole-exome sequencing revealed novel mutations in both patients (patient 1—c.923delC frame-shift mutation in the IL2RG gene, patient 2—c.G172A a homozygous missense mutation in the JAK3 gene). Bioinformatic analysis of the JAK3 mutation indicated deleterious effect and 3D protein modeling located the mutation to a surface exposed alpha-helix structure. Our findings help to link between genotype and phenotype, which is a key factor for the diagnosis and treatment of SCID patients.

BACKGROUND: Animal studies have demonstrated fetal acidosis during carbon dioxide pneumoperitoneum. This finding suggests a potential adverse effect of [CO.sub.2] pneumoperitoneum on fetal outcome in humans. PATIENTS AND METHODS: We reviewed our recent experience with laparoscopic surgery performed under general anesthesia and with the use of [CO.sub.2] pneumoperitoneum, in pregnant women with appendicitis or cholecystitis. We compared these women's charts and pregnancy outcomes with those of pregnant women who underwent formal laparotomy during the same period of time. RESULTS: Seven pregnant patients underwent laparoscopic surgery, and there were 4 fetal deaths among them (3 during the first postoperative week, and another 4 weeks postoperatively). Five pregnant patients underwent formal laparotomy, of whom 4 subsequently progressed to term and 1 was lost to follow-up. CONCLUSIONS: Our recent experiences together with the available animal data suggest that caution should be used when considering nonobstetrical laparoscopic surgery in pregnant women. This experience suggests that additional clinical and laboratory investigations may be indicated to evaluate fetal risk associated with such surgery. Am J Surg. 1996;171:435-437.

CD4+ T cells are vital for host defense and immune regulation. However, the fundamental role of CD4 itself remains enigmatic. We report seven patients aged 5–61 years from five families of four ancestries with autosomal recessive CD4 deficiency and a range of infections, including recalcitrant warts and Whipple’s disease. All patients are homozygous for rare deleterious CD4 variants impacting expression of the canonical CD4 isoform. A shorter expressed isoform that interacts with LCK, but not HLA class II, is affected by only one variant. All patients lack CD4+ T cells and have increased numbers of TCRαβ+CD4−CD8− T cells, which phenotypically and transcriptionally resemble conventional Th cells. Finally, patient CD4−CD8− αβ T cells exhibit intact responses to HLA class II–restricted antigens and promote B cell differentiation in vitro. Thus, compensatory development of Th cells enables patients with inherited CD4 deficiency to acquire effective cellular and humoral immunity against an unexpectedly large range of pathogens. Nevertheless, CD4 is indispensable for protective immunity against at least human papillomaviruses and Trophyrema whipplei.

Dysregulated immune responses are essential underlying causes of a plethora of pathologies including cancer, autoimmunity, and immunodeficiency. We here investigated 4 patients from unrelated families presenting with immunodeficiency, autoimmunity, and malignancy. We identified 4 distinct homozygous mutations in TNFRSF9 encoding the tumor necrosis factor receptor superfamily member CD137/4-1BB, leading to reduced, or loss of, protein expression. Lymphocytic responses crucial for immune surveillance, including activation, proliferation, and differentiation, were impaired. Genetic reconstitution of CD137 reversed these defects. CD137 deficiency is a novel inborn error of human immunity characterized by lymphocytic defects with early-onset Epstein-Barr virus (EBV)-associated lymphoma. Our findings elucidate a functional role and relevance of CD137 in human immune homeostasis and antitumor responses.

Neural progenitor cells undergo somatic retrotransposition events, mainly involving L1 elements, which can be potentially deleterious. Here, we analyze the whole genomes of 20 brain samples and 80 non-brain samples, and characterized the retrotransposition landscape of patients affected by a variety of neurodevelopmental disorders including Rett syndrome, tuberous sclerosis, ataxia-telangiectasia and autism. We report that the number of retrotranspositions in brain tissues is higher than that observed in non-brain samples and even higher in pathologic vs normal brains. The majority of somatic brain retrotransposons integrate into pre-existing repetitive elements, preferentially A/T rich L1 sequences, resulting in nested insertions. Our findings document the fingerprints of encoded endonuclease independent mechanisms in the majority of L1 brain insertion events. The insertions are “non-classical” in that they are truncated at both ends, integrate in the same orientation as the host element, and their target sequences are enriched with a CCATT motif in contrast to the classical endonuclease motif of most other retrotranspositions. We show that L1Hs elements integrate preferentially into genes associated with neural functions and diseases. We propose that pre-existing retrotransposons act as “lightning rods” for novel insertions, which may give fine modulation of gene expression while safeguarding from deleterious events. Overwhelmingly uncontrolled retrotransposition may breach this safeguard mechanism and increase the risk of harmful mutagenesis in neurodevelopmental disorders.

Several letters to the editor are presented in response to articles in previous issues including withholding taxes in the April 3, 1948 issue, base for economic graphs and indices and bituminous coal production series.

We investigated the mucosal distribution and neutralization potency of rhesus recombinant versions of the HIV-specific, broadly neutralizing antibody b12 (RhB12) following intravenous administration to lactating rhesus monkeys. IgG and dimeric IgA (dIgA) administration resulted in high plasma concentrations of broadly neutralizing antibody (bnAb), but the monomeric IgA (mIgA) was rapidly cleared from the systemic compartment. Interestingly, differences in the distribution of the RhB12 isoform were observed between the mucosal compartments. The peak concentration of RhB12 IgG was higher than dIgA in saliva, rectal, and vaginal secretions, but the bnAb concentration in milk was one to two logs higher after dIgA administration than with IgG or mIgA infusion. Neutralization was observed in plasma of all animals, but only those infused with RhB12 dIgA showed moderate levels of virus neutralization in milk. Remarkably, virus-specific secretory IgA was detected in mucosal compartments following dIgA administration. The high milk RhB12 dIgA concentration suggests that passive immunization with dIgA could be more effective than IgG to inhibit virus in breast milk.

The analysis of individuals with telomere defects may shed light on the delicate interplay of factors controlling genome stability, premature aging, and cancer. We herein describe two Coats plus patients with telomere and genomic defects; both harbor distinct, novel mutations in STN1, a member of the human CTC1–STN1–TEN1 (CST) complex, thus linking this gene for the first time to a human telomeropathy. We characterized the patients’ phenotype, recapitulated it in a zebrafish model and rescued cellular and clinical aspects by the ectopic expression of wild-type STN1 or by thalidomide treatment. Interestingly, a significant lengthy control of the gastrointestinal bleeding in one of our patients was achieved by thalidomide treatment, exemplifying a successful bed-to-bench-and-back approach.

AbstractA large number of civilian agencies have published guides and recommendations on how to assemble personal and family emergency kits. However, the kits resulting from following these guidelines are impractical, particularly in the event evacuation becomes necessary. This report describes an alternative approach to assembling an emergency kit.OstrovskiyG, ShemeshAJ. Contents of a bug-out bag. Prehosp Disaster Med. 2018;33(6):647–649.

Background:The 22q11.2 deletion syndrome (22q11.2DS) is a congenital multisystem anomaly characterized by typical facial features, palatal anomalies, congenital heart defects, hypocalcemia, immunodeficiency, and cognitive and neuropsychiatric symptoms. The aim of our study was to investigate T- and B-lymphocyte characteristics associated with 22q11.2DS.Methods:Seventy-five individuals with 22q11.2DS were tested for T and B lymphocytes by examination of T-cell receptor rearrangement excision circles (TRECs) and B-cell ?-deleting recombination excision circles (KRECs), respectively.Results:The 22q11.2DS individuals displayed low levels of TRECs, while exhibiting normal levels of KRECs. There was a significant positive correlation between TREC and KREC in the 22q11.2DS group, but not in controls. Both TREC and KREC levels showed a significant decrease with age and only TREC was low in 22q11.2DS individuals with recurrent infections. No difference in TREC levels was found between 22q11.2DS individuals who underwent heart surgery (with or without thymectomy) and those who did not.Conclusion:T-cell immunodeficiency in 22q11.2DS includes low TREC levels, which may contribute to recurrent infections in individuals with this syndrome. A correlation between T- and B-cell abnormalities in 22q11.2DS was identified. The B-cell abnormalities could account for part of the immunological deficiency seen in 22q11.2DS.

Background:Glucose-6-phosphatase-β (G6PC3) deficiency is characterized by congenital neutropenia and variable developmental disorders, including those of the cardiovascular system and the urogenital system (e.g., cryptorchidism) and a peculiar visibility of subcutaneous veins.Methods:A patient with clinical findings suggestive of G6PC3 deficiency was investigated. Genetic, hematopathologic, immunologic, and endocrine work-up were performed.Results:The reported patient had binucleotide deletion mutation in G6PC3 and displayed the full spectrum of clinical manifestations associated with G6PC3 deficiency including neutropenia. The reported patient had normal bone marrow cellularity without increased apoptosis, and his neutrophils displayed normal respiratory burst activity. Endocrine work-up revealed low testosterone levels, which did not respond to human chorionic gonadotropin stimulation, extremely elevated luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels, and undetectable anti-Müllerian hormone, all of which are suggestive of testicular failure or anorchia.Conclusion:Our report extends the knowledge about this syndrome and suggests a role for G6PC3 in testicular differentiation and formation. Urogenital dysmorphism could indeed be unrelated to G6PC3 and secondary to consanguinity. However, given the similar description of urogenital anomalies in previous reports of this syndrome, the dysmorphism in our patient is likely related.

Absence of p53 expression or expression of mutant p53 (mtp53) are common in human cancers and are associated with increased cancer resistance to chemo- and radiotherapy. Therefore, significant efforts towards pharmaceutical reactivation of defective p53 pathways are underway. We previously reported that, in HIPK2 knockdown background, p53 undergoes misfolding with inhibition of DNA binding and transcriptional activities that correlate with increased chemoresistance, and that zinc rescues wild-type p53 activity. Zinc has a crucial role in the biology of p53, in that p53 binds to DNA through a structurally complex domain stabilized by zinc atom. In this study, we explored the role of zinc in p53 reactivation in mutant p53-expressing cancer cells. We found that zinc re-established chemosensitivity in breast cancer SKBR3 (expressing R175H mutation) and glioblastoma U373MG (expressing R273H mutation) cell lines. Biochemical studies showed that zinc partly induced the transition of mutant p53 protein (reactive to conformation-sensitive PAb240 antibody for mutant conformation) into a functional conformation (reactive to conformation-sensitive PAb1620 antibody for wild-type conformation). Zinc-mediated p53 reactivation also reduced the mtp53/p73 interaction restoring both wtp53 and p73 binding to target gene promoters by ChIP assay with in vivo induction of wtp53 target gene expression, which rendered mutant p53 cells more prone to drug killing in vitro. Finally, zinc administration in U373MG tumor xenografts increased drug-induced tumor regression in vivo, which correlated with increased wild-type p53 protein conformation. These results show that the use of zinc might restore drug sensitivity and inhibit tumor growth by reactivating mutant p53.

MeCP2, the major causative factor of Rett syndrome and related phenotypes including autism, is a two-face nuclear modulator acting via transcriptional and chromatin remodeling mechanisms. This study investigated the expression of several nuclear proteins and their dependence on MeCP2 dose and presence of the Rett causative R306C mutation. To this end, we developed in vitro models representing MeCP2 deficiency induced by siRNAs, and cells expressing the R306C mutation. Using an extended antibody microarray validated by specific assays, revealed that MeCP2 dose was correlated with specific nuclear proteins profiles including the BRM/SNF2 component of SWI/SNF complex, PRMT1 methyl transferase and HDAC2. Furthermore, while exposing the MeCP2 knock-down system to therapeutic concentrations of valproic acid (VPA), a known HDACs inhibitor, we observed a partial restoration of MeCP2 expression levels. Exposure to VPA also increased the levels of BRM, as well as of BDNF, an important co-factor in MeCP2-mediated pathway. Our findings provide additional evidence of diverse mechanisms of MeCP2 function as transcriptional repressor and activator of specific genes. As it has been recently demonstrated that post-natal restoration of MeCP2 deficiency may reverse neurological defects in a mouse model of Rett syndrome, we suggest to study the restorative effect of HDAC inhibitors in MeCP2-deficient mouse model.

The BCL6 transcriptional repressor mediates survival, proliferation, and differentiation blockade of B cells during the germinal-center reaction and is frequently misregulated in B-cell non-Hodgkin lymphoma (BNHL). The p53 tumor-suppressor gene is central to tumorigenesis. Microarray analysis identified BCL6as a primary target of p53. The BCL6intron 1 contains a region in which 3 types of genetic alterations are frequent in BNHL: chromosomal translocations, point mutations, and internal deletions. We therefore defined it as TMDR (translocations, mutations, and deletions region). The BCL6gene contains a p53 response element (p53RE) residing within the TMDR. This p53RE contains a motif known to be preferentially targeted by somatic hypermutation. This p53RE is evolutionarily conserved only in primates. The p53 protein binds to this RE in vitro and in vivo. Reporter assays revealed that the BCL6p53RE can confer p53-dependent transcriptional activation. BCL6 mRNA and protein levels increased after chemotherapy/radiotherapy in human but not in murine tissues. The increase in BCL6 mRNA levels was attenuated by the p53 inhibitor PFT-α. Thus, we define the BCL6gene as a new p53 target, regulated through a RE frequently disrupted in BNHL.

The BCL6 transcriptional repressor mediates survival, proliferation, and differentiation blockade of B cells during the germinal-center reaction and is frequently misregulated in B-cell non-Hodgkin lymphoma (BNHL). The p53 tumor-suppressor gene is central to tumorigenesis. Microarray analysis identified BCL6 as a primary target of p53. The BCL6 intron 1 contains a region in which 3 types of genetic alterations are frequent in BNHL: chromosomal translocations, point mutations, and internal deletions. We therefore defined it as TMDR (translocations, mutations, and deletions region). The BCL6 gene contains a p53 response element (p53RE) residing within the TMDR. This p53RE contains a motif known to be preferentially targeted by somatic hypermutation. This p53RE is evolutionarily conserved only in primates. The p53 protein binds to this RE in vitro and in vivo. Reporter assays revealed that the BCL6 p53RE can confer p53-dependent transcriptional activation. BCL6 mRNA and protein levels increased after chemotherapy/radiotherapy in human but not in murine tissues. The increase in BCL6 mRNA levels was attenuated by the p53 inhibitor PFT-α. Thus, we define the BCL6 gene as a new p53 target, regulated through a RE frequently disrupted in BNHL.

The nuclear envelope separates the chromosomes from cytoplasm in eukaryotic cells and consists of three main domains: inner and outer nuclear membranes and nuclear pore complexes. The inner nuclear membrane maintains close associations with the underlying chromatin and nuclear lamina. For many years, the nuclear envelope was thought to function mainly as an architectural stabilizer of the nucleus, participating in assembly and disassembly processes during mitosis. However, recent findings demonstrate that nuclear envelope proteins are involved in fundamental nuclear functions, such as gene transcription and DNA replication, and that inherited or de novomutated proteins cause human diseases, termed “nuclear envelopathies.” These findings emphasize the importance of understanding the functions of this cellular domain, in both physiologic and pathologic states. To date, mutations in the genes encoding the nuclear envelope proteins emerin, MAN1, lamin A/C, and lamin B receptor were found to cause nuclear envelopathies. The diseases that are caused by mutations in LMNAgene are collectively called “laminopathies.” Nuclear envelopathies have diverse clinical phenotypes, ranging from cardiac and skeletal myopathies to partial lipodystrophy, peripheral neuropathy, and premature aging. This raises the question of how do such ubiquitously expressed proteins give rise to tissue-specific disease phenotypes. One possible explanation is the involvement of nuclear envelope proteins in the regulation of gene transcription, a novel mechanism that has been the focus of research in our lab in recent years. In this review, we describe recent discoveries in the field of nuclear envelopathies and discuss current proposed pathophysiological mechanisms underlying these diseases.

Purpose: We expect that the mutation panel currently recommended for preconception/prenatal CF carrier screening will be modified as new information is learned regarding the phenotype associated with specific mutations and allele frequencies in various populations. One such example is the I148T mutation, originally described as a severe CF mutation. After implementation of CF population-based carrier screening, we learned that I148T exists as a complex allele with 3199del6 in patients with clinical CF, whereas asymptomatic compound heterozygotes for I148T and a second severe CF mutation were negative for 3199del6.Methods: We performed reflex testing for 3199del6 on 663 unrelated specimens, including I148T heterozygotes, compound heterozygotes, and a homozygous individual.Results: Less than 1% of I148T carriers were also positive for 3199del6. Excluding subjects tested because of a suspected or known CF diagnosis or positive family history, 0.6% of I148T-positive individuals were also positive for 3199del6. We identified 1 I148T homozygote and 6 unrelated compound heterozygous individuals with I148T and a second CF variant (2 of whom also carried 3199del6). In addition, one fetus with echogenic bowel and one infertile male were heterozygous for I148T (3199del6 negative).Conclusions: Reflex testing for 3199del6 should be considered whenever I148T is identified. Reflex testing is of particular importance for any symptomatic patient or whenever one member of a couple carries a deleterious CF mutation and the other member is an I148T heterozygote. Further population data are required to determine if I148T, in the absence of 3199del6, is associated with mild or atypical CF or male infertility.

Summary.: We study here in detail the location of the real and complex zeros of the partial sums of and , which extends results of Szeg� (1924) and Kappert (1996).

LAP2β is an integral membrane protein of the nuclear envelope involved in chromatin and nuclear architecture. Using the yeast two-hybrid system, we have cloned a novel LAP2β-binding protein, mGCL, which contains a BTB/POZ domain and is the mouse homologue of the Drosophila germ-cell-less (GCL) protein. In Drosophila embryos, GCL was shown to be essential for germ cell formation and was localized to the nuclear envelope. Here, we show that, in mammalian cells, GCL is co-localized with LAP2β to the nuclear envelope. Nuclear fractionation studies reveal that mGCL acts as a nuclear matrix component and not as an integral protein of the nuclear envelope. Recently, mGCL was found to interact with the DP3α component of the E2F transcription factor. This interaction reduced the transcriptional activity of the E2F-DP heterodimer, probably by anchoring the complex to the nuclear envelope. We demonstrate here that LAP2β is also capable of reducing the transcriptional activity of the E2F-DP complex and that it is more potent than mGCL in doing so. Co-expression of both LAP2β and mGCL with the E2F-DP complex resulted in a reduced transcriptional activity equal to that exerted by the pRb protein.

We report the clinical presentation and outcome of 299 Malawian children with non-typhoidal Salmonella(NTS) bacteraemia and no evidence of focal sepsis, admitted to Queen Elizabeth Central Hospital (QECH), Blantyre, over a 26-month period (February 1996–April 1998). A peak incidence during the rainy season was noted. Salmonella typhimurium(79%) and S. enteritidis(13%) were the commonest isolates. For children aged >6 months, NTS bacteraemia was significantly associated with malarial parasitaemia (RR 1·5 [1·2, 2·2], P< 0·01) and with severe anaemia (RR 7·2 [3·4, 15·3], P< 0·0001), when compared to other common pathogens causing childhood bacteraemia. Clinical overlap with malaria and anaemia, and the presence of malarial parasitaemia on admission, may delay diagnosis. NTS bacteraemia was commonly diagnosed following blood transfusion. Resistance in vitroto ampicillin (79%), co-trimoxazole (72%) and gentamicin (55%) was very common, and was rare to chloramphenicol (0·3%) which is the antibiotic of choice for NTS sepsis at QECH. Overall mortality was high (23%). Young age and clinical HIV infection were risk factors for mortality. Recurrences of NTS bacteraemia following antibiotic therapy were common among children with clinical HIV infection.

There are no published data for the incidence or etiology of childhood bacteremia in Malawi. We describe the clinical and microbiologic features of children admitted to hospital from whom blood cultures yielded bacterial pathogens.

Implementation of newborn screening (NBS) programs for severe combined immunodeficiency (SCID) have advanced the diagnosis and management of affected infants and undoubtedly improved their outcomes. Reporting long-term follow-up of such programs is of great importance.

1. The foraging activities of the papilionid butterflies Ornithoptera priamus poseidon and Papilio ulysses, and the solitary bee Amegilla sapiens (Apoidea, Anthophoridae) on the shrub Stachytarpheta mutabilis were studied in highland Papua New Guinea. 2. The insects' activity patterns were analysed at three sites with differing diurnal microclimate variation. O. priamus and A. sapiens foraged in the morning (after a period of basking and wing-whirring) and late afternoon when temperatures were well below daily maxima, whereas P. ulysses showed foraging peaks during the hottest part of the day. 3. Site choice by all 3 species appeared to be determined primarily by temperature, but within the limits imposed by temperature, nectar supplies probably determined which site was visited. 4. P. ulysses showed interspersed foraging and courtship behaviour, and no behavioural switching was observed for this species. At high temperatures, both O. priamus and A. sapiens ceased foraging and showed territorial and courtship behaviour. This behavioural change allowed avoidance of heat stress, and occurred even when nectar supplies were maintained at high levels. 5. Thermal effects on behavioural switching in these insects are compared with related phenomena in other bees and butterflies.

A total of 21 infertile men with congenital unilateral absence of the vas deferens (CUAVD) were studied to determine if this disorder involves mutations in the cystic fibrosis (CF) gene. This hypothesis derives from previous work which has established the genetic commonality of CF and congenital bilateral absence of the vas deferens (CBAVD). Both CF and CBAVD may result from compound heterozygosity for CF mutations. In our patients with unilateral vasal aplasia, 12 had anatomically complete and patent vasa deferentia on the contralateral side, i.e. side of the scrotally palpable vas. No CF mutations were detected in this subgroup. The remaining nine patients had a non-iatrogenic occlusion of the contralateral vas at either the inguinal or pelvic level. In this subgroup, eight out of nine (89%) had a mutation detected in one of their two CF genes. This is the first study to define accurately the clinically and anatomically heterogeneous nature of CUAVD and to begin to clarify the genetic basis of unilateral absence of the vas deferens.

Summary We investigate the location of the zeros of the normalized generalized Bessel polynomials and the normalized reversed generalized Bessel polynomials. Also, the rate at which these zeros approach certain well-defined curves is investigated. On the basis of numerical computations and graphs, four new conjectures are proposed.

Ten F1hybrids of maize (Zea maysL.) grown at two day/night temperatures (35/25 C and 40/28 C) in controlled‐environment chambers were assayed for in vitro nitrate reductase (NR) to compare the relative effect of high temperature on nitrate reductase activity (NRA) among hybrids. High temperature response of nitrate reductase was tested by assaying glutamine synthetase (GS) and NADH‐glutamate dehydrogenase (GDH) from temperature‐treated seedlings in a set of genotypes that differed for the degree of high temperature stability of nitrate reductase. The NRA of most hybrids was reduced approximately 35% by high temperature, and the overall genetic variability of NRA for temperature stability was low. However, the NRA of some hybrids, such as ‘A632Ht × B37Ht’, was depleted less by high temperature (22 and 17% reduction in two experiments, respectively) than others, such as ‘Oh51A × Oh551× (54 and 31% reduction), indicating that genotypic differences can occasionally be large. Genotypic variability for NR response to temperature was not correlated with that for GS or GDH, neither of which activities were reduced significantly by high temperature in any of six genotypes. The effect on NR of the addition of protein to the NR extraction medium was tested using tissue from seedlings grown at high and low temperatures. This addition had no detectable influence on the apparent temperature stability of genotypes. Protein addition, however, did slightly increase NRA of some of the genotypes. Increases of NRA due to addition of bovine serum albumin ranged from 0 to 30%

Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene but the association between mutation (genotype) and disease presentation (phenotype) is not straightforward. We have been investigating whether variants in the CFTR gene that alter splicing efficiency of exon 9 can affect the phenotype produced by a mutation. A missense mutation, R117H, which has been observed in three phenotypes, was found to occur on two chromosome backgrounds with intron 8 variants that have profoundly different effects upon splicing efficiency. A close association is shown between chromosome background of the R117H mutation and phenotype. These findings demonstrate that the genetic context in which a mutation occurs can play a significant role in determining the type of illness produced.

CF and CBAVD are really just ends of a clinical spectrum. The type and nature of the mutations in the CF gene probably determine the phenotypic expression of the patient. Perhaps all patients homozygous for ?F508, for example, will have severe pulmonary and pancreatic disease as well as absent vasa, whereas those with other combinations, such as ?F508/D1270N, will be unaffected in terms of pulmonary and pancreatic function but will have absent vasa. Besides contributing to a better understanding of the nature of CBAVD, this linkage of CF and CBAVD most importantly mandates genetic screening and counseling for appropriate family members and even the patient's spouse. In addition, a broader understanding of CF is now at hand, as this brings a whole new cohort of patients under the CF umbrella. Many of these will have at least one, if not two, rare or novel CF gene mutations. Once all of these mutations have been detected and defined, our knowledge of the CF gene, its mutations, and their implications will be dramatically expanded.

Summary.: With denoting the -th partial sum of ${\rm e}^{z}$, the exact rate of convergence of the zeros of the normalized partial sums, , to the Szeg\"o curve was recently studied by Carpenter et al. (1991), where is defined by Here, the above results are generalized to the convergence of the zeros and poles of certain sequences of normalized Pad\'{e} approximants to , where is the associated Pad\'{e} rational approximation to .

The carcinogenic potency of simple aliphatic alkylating agents such as the alkylnitrosamides and the alkylmethanesulphonates is positively correlated with their ability to alkylate the relatively weakly nucleophilic oxygen atoms in DNA, particularly the O6-atom of guanine1–4. Differences in the spectrum of DNA alkylations produced by these agents can be rationalised on chemical grounds in that the electrophilic reactivity of the alkylating species determines the extent to which it will react at sites of weaker nucleophilicity4–6. Alkylation of the more strongly nucleophilic ring nitrogen atoms of the purine bases, which is the main site of reaction with all these agents, appears to be much less important in alkylation carcinogenesis. O6-alkyI-ation of guanine is likely to interfere with DNA base-pair hydrogen bonding7and is possibly the major DNA modification responsible for the induction of GC → AT transition mutations in bacteria and bacteriophage by alkylating agents8–10. Here, we have studied the effects of three methylating agents of contrasting carcinogenic potency on mammalian (V79 Chinese hamster) cells in culture. We report that the mutagenicity but not the cytotoxicity of each agent reflects its carcinogenicity and, furthermore, that the marked differences in mutagenicity are closely paralleled by differences in levels of O6-guanine methylation.

A comparison has been made between the carcinogenic activities of benzo(a)pyrene and the proposed proximate carcinogen, benzo(a)pyrene 7,8-dihydrodiol, in the adult C57BL mouse submandibular salivary gland. In preliminary studies using a range of doses, the dihydrodiol was slightly less active than the parent hydrocarbon in this system. There was a difference in the type of tumour induced by the 2 compounds. Benzo(a)pyrene induced tumours of the salivary glands at the site of injection, whereas the dihydrodiol induced malignant lymphosarcomas, particularly of the thymus, which were often metastatic to other orgnas. Possible reasons for the different sites of action of the 2 compounds are discussed.

WithE2n(|x|) denoting the error of best uniform approximation to |x| by polynomials of degree at most 2n on the interval [−1, +1], the famous Russian mathematician S. Bernstein in 1914 established the existence of a positive constantβ for which lim 2nE2n(|x|)=β.n→∞ Moreover, by means of numerical calculations, Bernstein determined, in the same paper, the following upper and lower bounds forβ: 0.278<β<0.286. Now, the average of these bounds is 0.282, which, as Bernstein noted as a “curious coincidence,” is very close to 1/(2√π)=0.2820947917... This observation has over the years become known as the Bernstein Conjecture: Isβ=1/(2√π)? We show here that the Bernstein conjecture isfalse. In addition, we determine rigorous upper and lower bounds forβ, and by means of the Richardson extrapolation procedure, estimateβ to approximately 50 decimal places.

We present movement data for a species of New Guinea “giant rat”, Mallomys rothschildi, as a test of the efficacy of a recently developed method of spool‐and‐line tracking in short‐term ecological/behavioural studies. We demonstrate that M. rothschildiis scansorial, feeds on shoots of Pandanusspp., and ranges freely over large areas without apparently being constrained by a fixed “home” nest. Another species, Hyomys golialh, occurs sympatrically and is superficially virtually indistinguishable from M. rolhschildi.Data from the single individual tracked suggest that the two species are ecologically segregated on the basis of clear behavioural differences. We note the considerable advantages of spool‐and‐line tracking over radio tracking in this type of study.

Dirithromycin is the 9-N,11-O-oxazine adduct formed from 9(S)-erythromycylamine and 2-(2-methoxyethoxy)acetaldehyde in which the methoxyethoxymethyl substituent on the oxazine ring possesses the R configuration. Epidirithromycin is its isomer in which the methoxyethoxymethyl substituent has the opposite (S) configuration. Both compounds readily epimerize in solution, reaching an equilibrium ratio of 85:15 in favor of dirithromycin, given sufficient time. The rate of interconversion is dependent upon pH, temperature, and solvent. An enriched sample of epidirithromycin (95% purity) was synthesized by condensing erythromycylamine and 2-(2-methoxyethoxy)acetaldehyde in diethyl ether as the reaction solvent, and the product was fully characterized by nuclear magnetic resonance spectroscopy and high-pressure liquid chromatographic (HPLC) analysis. Both oxazine derivatives readily hydrolyze to erythromycylamine, so all three compounds exhibit the same antibiotic activity in vitro. In order to determine whether dirithromycin itself possesses significant antimicrobial activity without initial hydrolysis to erythromycylmine, inhibition of cell-free ribosomal protein synthesis was measured under conditions which were adapted to minimize hydrolysis, as measured by analytical HPLC in parallel experiments. Under these particular conditions, inhibition of ribosomal protein synthesis by dirithromycin was < 10% of the value measured for erythromycylamine.