Epstein-Barr virus-related dacryocystitis: a case report.

BACKGROUND AND OBJECTIVE: Acute dacryocystitis is an atypical and rare manifestation of pediatric mononucleosis still widely underdiagnosed in clinical practice. We report this rare condition and describe challenges in its diagnosis and treatment on the basis of a presented case. CASE PRESENTATION: A 6-year-old Caucasian girl without any ophthalmic history was admitted for right preseptal cellulitis requiring intravenous antibiotic therapy. During hospitalization, she developed a fluctuating lump in the nasolacrimal region which resembled an abscess, both clinically and radiologically. There was no spontaneous purulent discharge. Serology was positive for acute mononucleosis and Epstein-Barr virus-related dacryocystitis was diagnosed. Following multidisciplinary discussion, she was treated conservatively with digital lacrimal sac massages and intravenous antibiotic therapy with an excellent outcome. DISCUSSION: This rare form of Epstein-Barr virus is poorly documented in the literature, and thus barely known. As initial symptoms are nonspecific (rhinitis, fever, eyelid edema and erythema lack of purulent discharge, and moderate bilateral cervical lymphadenopathy), diagnosis is often difficult. Nevertheless, differentiating between dacryocystitis and abscess is crucial to select the appropriate treatment and avoid unnecessary, potentially harmful surgery. Conservative management of dacryocystitis appears to be the gold standard of treatment. CONCLUSION: Acute dacryocystitis in children free of ophthalmic history should raise suspicion of primary Epstein-Barr virus infection. With conservative treatment, prognosis appears to be excellent; therefore, surgery should be avoided as much as possible.

Student perception of a new integrated anatomy practical program: does students' prior learning make a difference?

While there is evidence that science and non-science background students display small differences in performance in basic and clinical sciences, early in a 4-year, graduate entry medical program, this lessens with time. With respect to anatomy knowledge, there are no comparable data as to the impact previous anatomy experience has on the student perception of the anatomy practical learning environment. A study survey was designed to evaluate student perception of the anatomy practical program and its impact on student learning, for the initial cohort of a new medical school. The survey comprised 19 statements requiring a response using a 5-point Likert scale, in addition to a free text opportunity to provide opinion of the perceived educational value of the anatomy practical program. The response rate for a total cohort of 82 students was 89%. The anatomy practical program was highly valued by the students in aiding their learning of anatomy, as indicated by the high mean scores for all statements (range: 4.04-4.7). There was a significant difference between the students who had and had not studied a science course prior to entering medicine, with respect to statements that addressed aspects of the course related to its structure, organization, variety of resources, linkage to problem-based learning cases, and fairness of assessment. Nonscience students were more positive compared to those who had studied science before (P levels ranging from 0.004 to 0.035). Students less experienced in anatomy were more challenged in prioritizing core curricular knowledge. Clin. Anat. 24:664-670, 2011. © 2011 Wiley-Liss, Inc.

Proximal arterial vasoconstriction precedes regression of the hyaloid vasculature.

PURPOSE: To determine whether constriction of proximal arterial vessels precedes involution of the distal hyaloid vasculature in the mouse, under normal conditions, and whether this vasoconstriction is less pronounced when the distal hyaloid network persists, as it does in oxygen-induced retinopathy (OIR). METHODS: Photomicrographs of the vasa hyaloidea propria were analysed from pre-term pups (1-2 days prior to birth), and on Days 1-11 post-birth. The OIR model involved exposing pups to approximately 90% O(2) from D1-5, followed by return to ambient air. At sampling times pups were anaesthetised and perfused with india ink. Retinal flatmounts were also incubated with FITC-lectin (BS-1, G. simplicifolia,); this labels all vessels, allowing identification of vessels not patent to the perfusate. RESULTS: Mean diameter of proximal hyaloid vessels in pre-term pups was 25.44 +/- 1.98 microm; +/- 1 SEM). Within 3-12 hrs of birth, significant vasoconstriction was evident (diameter:12.45 +/- 0.88 microm), and normal hyaloid regression subsequently occurred. Similar vasoconstriction occurred in the O(2)-treated group, but this was reversed upon return to room air, with significant dilation of proximal vessels by D7 (diameter: 31.75 +/- 11.99 microm) and distal hyaloid vessels subsequently became enlarged and tortuous. CONCLUSIONS: Under normal conditions, vasoconstriction of proximal hyaloid vessels occurs at birth, preceding attenuation of distal hyaloid vessels. Vasoconstriction also occurs in O(2)-treated pups during treatment, but upon return to room air, the remaining hyaloid vessels dilate proximally, and the distal vessels become dilated and tortuous. These observations support the contention that regression of the hyaloid network is dependent, in the first instance, on proximal arterial vasoconstriction.

Segmental duplications: organization and impact within the current human genome project assembly.

Segmental duplications play fundamental roles in both genomic disease and gene evolution. To understand their organization within the human genome, we have developed the computational tools and methods necessary to detect identity between long stretches of genomic sequence despite the presence of high copy repeats and large insertion-deletions. Here we present our analysis of the most recent genome assembly (January 2001) in which we focus on the global organization of these segments and the role they play in the whole-genome assembly process. Initially, we considered only large recent duplication events that fell well-below levels of draft sequencing error (alignments 90%-98% similar and > or =1 kb in length). Duplications (90%-98%; > or =1 kb) comprise 3.6% of all human sequence. These duplications show clustering and up to 10-fold enrichment within pericentromeric and subtelomeric regions. In terms of assembly, duplicated sequences were found to be over-represented in unordered and unassigned contigs indicating that duplicated sequences are difficult to assign to their proper position. To assess coverage of these regions within the genome, we selected BACs containing interchromosomal duplications and characterized their duplication pattern by FISH. Only 47% (106/224) of chromosomes positive by FISH had a corresponding chromosomal position by comparison. We present data that indicate that this is attributable to misassembly, misassignment, and/or decreased sequencing coverage within duplicated regions. Surprisingly, if we consider putative duplications >98% identity, we identify 10.6% (286 Mb) of the current assembly as paralogous. The majority of these alignments, we believe, represent unmerged overlaps within unique regions. Taken together the above data indicate that segmental duplications represent a significant impediment to accurate human genome assembly, requiring the development of specialized techniques to finish these exceptional regions of the genome. The identification and characterization of these highly duplicated regions represents an important step in the complete sequencing of a human reference genome.

Integration of cytogenetic landmarks into the draft sequence of the human genome.

We have placed 7,600 cytogenetically defined landmarks on the draft sequence of the human genome to help with the characterization of genes altered by gross chromosomal aberrations that cause human disease. The landmarks are large-insert clones mapped to chromosome bands by fluorescence in situ hybridization. Each clone contains a sequence tag that is positioned on the genomic sequence. This genome-wide set of sequence-anchored clones allows structural and functional analyses of the genome. This resource represents the first comprehensive integration of cytogenetic, radiation hybrid, linkage and sequence maps of the human genome; provides an independent validation of the sequence map and framework for contig order and orientation; surveys the genome for large-scale duplications, which are likely to require special attention during sequence assembly; and allows a stringent assessment of sequence differences between the dark and light bands of chromosomes. It also provides insight into large-scale chromatin structure and the evolution of chromosomes and gene families and will accelerate our understanding of the molecular bases of human disease and cancer.

Comparative mapping of the region of human chromosome 7 deleted in williams syndrome.

Williams syndrome (WS) is a complex developmental disorder resulting from the deletion of a large (approximately 1.5-2 Mb) segment of human chromosome 7q11.23. Physical mapping studies have revealed that this deleted region, which contains a number of known genes, is flanked by several large, nearly identical blocks of DNA. The presence of such highly related DNA segments in close physical proximity to one another has hampered efforts to elucidate the precise long-range organization of this segment of chromosome 7. To gain insight about the structure and evolutionary origins of this important and complex genomic region, we have constructed a fully contiguous bacterial artificial chromosome (BAC) and P1-derived artificial chromosome (PAC) contig map encompassing the corresponding region on mouse chromosome 5. In contrast to the difficulties encountered in constructing a clone-based physical map of the human WS region, the BAC/PAC-based map of the mouse WS region was straightforward to construct, with no evidence of large duplicated segments, such as those encountered in the human WS region. To confirm this difference, representative human and mouse BACs were used as probes for performing fluorescence in situ hybridization (FISH) to metaphase and interphase chromosomes. Human BACs derived from the nonunique portion of the WS region hybridized to multiple, closely spaced regions on human chromosome 7q11.23. In contrast, corresponding mouse BACs hybridized to a single site on mouse chromosome 5. Furthermore, FISH analysis revealed the presence of duplicated segments within the WS region of various nonhuman primates (chimpanzee, gorilla, orangutan, and gibbon). Hybridization was also noted at the genomic locations corresponding to human chromosome 7p22 and 7q22 in human, chimpanzee, and gorilla, but not in the other animal species examined. Together, these results indicate that the WS region is associated with large, duplicated blocks of DNA on human chromosome 7q11.23 as well as the corresponding genomic regions of other nonhuman primates. However, such duplications are not present in the mouse.

A genomic region encompassing a cluster of olfactory receptor genes and a myosin light chain kinase (MYLK) gene is duplicated on human chromosome regions 3q13-q21 and 3p13.

The olfactory receptor (OR) multigene family is widely distributed in the human genome. We characterize here a new cluster of four OR genes (HGMW-approved symbols OR7E20P, OR7E6P, OR7E21P, and OR7E22P) on human chromosome 3p13 that is contained in an approximately 250-kb region. This region has been physically mapped, and a 106-kb portion containing the OR genes has been sequenced. All the OR sequences are disrupted by frameshifts and stop codons and appear to have arisen through local duplications. A myosin light chain kinase pseudogene (HGMW-approved symbol MYLKP) lies at one end of the OR gene cluster. Sequences spanning the entire region are also present at 3q13-q21, the site of the functional MYLK gene. This region duplicated locally before the divergence of primates, and the two paralogous copies were later separated to sites on either side of the centromere. This study increases our understanding of the evolution of the human genome. The 3p13 cluster is the first example of a tandem array of OR pseudogenes, and duplications of such clusters may account for the accumulation of a large number of pseudogenes in the human genome.

An 18q- syndrome breakpoint resides between the duplicated serpins SCCA1 and SCCA2 and arises via a cryptic rearrangement with satellite III DNA.

The 18q-syndrome is representative of a group of terminal deficiency or macrodeletion syndromes characterized by mental retardation and congenital malformations. To gain insight into the mechanism of chromosomal loss and stabilization in these disorders, we cloned a putative terminal deletion breakpoint from an 18q-syndrome patient. The 18q21.3 breakpoint occurred between two nearly identical serine protease inhibitor (serpin) genes, SCCA1 and SCCA2. Although cytogenetic studies suggested that this chromosomal aberration was formed by a simple terminal deletion, DNA sequence analysis, pulsed-field gel electrophoresis and fluorescence in situ hybridization showed that the breakpoint was contiguous with a 35 bp filler sequence followed by a satellite III DNA-containing telomeric fragment of 475-1000 kb. This type of satellite III DNA sequence was not detected on the normal chromosome 18, but was highly homologous with types of satellite III DNA sequences normally located on the short arms (p11) of the acrocentric chromosomes and other heterochromatic regions. This DNA sequence analysis suggested that the terminal deficiency in this 18q-syndrome patient arose via illegitimate (non-homologous) recombination. Moreover, these data raise the possibility that a subset of chromosomal aberrations appearing cytogenetically and molecularly as simple terminal truncations or deletions are caused by small (<1000 kb) cryptic rearrangements.

Effects of unilateral ovariectomy with compensatory hypertrophy on ovarian blood flow, oxygen consumption and progestin secretion in the 16-day pregnant rat.

Stimulated ovulation with resultant multiple corpora lutea (CL) can result in lower progesterone levels than expected from the increased luteal tissue mass. Unilateral ovariectomy (ULO) was used to increase CL number in rats and determine whether this would compromise luteal tissue blood flow, oxygen consumption and progestin secretion. All investigations were performed in vivo, using a venous outflow technique on Day 16 of gestation, when progesterone secretion is maximal. ULO, performed before pregnancy, doubled CL number and total CL mass in the remaining ovary of six treated compared to five control rats. Growth of CL was not affected. The rate of ovarian blood flow (microL min(-1) mg CL(-1)) fell to 47% of control levels in ULO animals and progesterone secretion (microg h(-1) mg CL(-1)) to 68%. Secretion of the minor progestin, 20alpha-hydroxypregn-4-en-one was not affected. Tissue oxygen consumption was maintained despite the reduction in blood flow by an increase in oxygen extraction from arterial blood. These results suggest that overcrowding of CL in ULO-stimulated rat ovaries compromises luteal tissue blood flow and subsequently progesterone secretion.

Identification, characterization, and mapping of a mouse homolog of the gene mutated in Nijmegen breakage syndrome.

The rare autosomal recessive disorder Nijmegen breakage syndrome (NBS) results from mutations in the NBS1 gene on human chromosome 8q21. A mouse homolog of the NBS1 gene was isolated and its nucleotide sequence determined. Somatic cell hybrid analysis and fluorescence in situ hybridization were used to map this gene, Nbn, to mouse chromosome band 4A. Northern blotting revealed comparable levels of Nbn transcripts in most tissues in the mouse. However, transcripts were elevated 10-20 fold in the testes, consistent with a possible role for the product of the Nbn gene in meiotic recombination.

Complete physical map of the common deletion region in Williams syndrome and identification and characterization of three novel genes.

Williams syndrome (WS) is a contiguous gene deletion disorder caused by haploinsufficiency of genes at 7q11.23. We have shown that hemizygosity of elastin is responsible for one feature of WS, supravalvular aortic stenosis (SVAS). We have also implicated LIM-kinase 1 hemizygosity as a contributing factor to impaired visual-spatial constructive cognition in WS. However, the common WS deletion region has not been completely characterized, and genes for additional features of WS, including mental retardation, infantile hypercalcemia, and unique personality profile, are yet to be discovered. Here, we present a physical map encompassing 1.5 Mb DNA that is commonly deleted in individuals with WS. Fluorescence in situ hybridization analysis of 200 WS individuals shows that WS individuals have the consistent deletion interval. In addition, we identify three novel genes from the common deletion region: WS-betaTRP, WS-bHLH, and BCL7B. WS-betaTRP has four putative beta-transducin (WD40) repeats, and WS-bHLH is a novel basic helix-loop-helix leucine zipper (bHLHZip) gene. BCL7B belongs to a novel family of highly conserved genes. We describe the expression profile and genomic structure for each of these genes. Hemizygous deletion of one or more of these genes may contribute to developmental defects in WS.

A murine ortholog of the human serpin SCCA2 maps to chromosome 1 and inhibits chymotrypsin-like serine proteinases.

Squamous cell carcinoma antigens (SCCA) 1 and 2 are inhibitory members of the high-molecular-weight serine proteinase inhibitor (serpin) family. The biological functions of SCCA1 and 2 are unknown. One approach to determining the function of human proteins is to study orthologs in other species, such as the mouse. The purpose of this study was to determine whether orthologs to human SCCA1 or 2 exist in the mouse. We report the identification and characterization of a novel serpin, sqn5 (now designated Scca2). Comparative amino acid sequence analysis suggests that Scca2 is a member of the ov-serpin subfamily of serpins with highest homology to SCCA1 and SCCA2. Fluorescence in situ hybridization revealed that the Scca2 mapped near Bcl2 on mouse chromosome 1. This region is syntenic with the human locus for SCCA1 and SCCA2 on 18q21.3. The tissue expression patterns as determined by RT-PCR showed a restricted distribution. Scca2 was detected in the lung, thymus, skin, and uterus, as are SCCA1 and SCCA2. Unlike the SCCAs, however, Scca2 was detected also in the gastrointestinal tract. Enzyme-inhibition assays using a GST-SCCA2 fusion protein revealed that SCCA2 inhibited chymotrypsin-like serine proteinases, but not papain-like cysteine proteinases. SCCA2 inhibited CTSG at 1:1 stoichiometry and with a second-order rate constant of kass = 1.7 x 10(5) M-1 s-1. SCCA2 also inhibited human mast cell chymase but the stoichiometry was 2:1, and the second-order rate constant was kass = 0.9 x 10(4) M-1 s-1. This inhibitory profile is identical to that observed for human SCCA2. Based on these findings, Scca2 appears to be the murine ortholog of human SCCA2.

Large multi-chromosomal duplications encompass many members of the olfactory receptor gene family in the human genome.

The human genome contains thousands of genes that encode a diverse repertoire of odorant receptors (ORs). We report here on the identification and chromosomal localization of 74 OR-containing genomic clones. Using fluorescence in situ hybridization (FISH), we demonstrate a striking homology among a set of approximately 20 OR locations, illustrating a history of duplications that have distributed OR sequences across the genome. Half of the OR-containing BACs cloned from total genomic DNA and 86% of cosmids derived from chromosome 3 cross-hybridize to a subset of these locations, many to 17 of them. These paralogous regions are distributed on 13 chromosomes, and eight lie in terminal bands. By analyzing clones from an approximately 250 kb clone-walk across one of these sites (3p13), we show that the homology among these sites is extensive (>150 kb) and encompasses both OR genes and intergenic genomic sequences. The FISH signals appear significantly larger at some sites than at the native location, indicating that portions of some duplicons have undergone local amplification/attrition. More restricted duplications involving pairs of other genomic locations are detected with 12% of the OR-BACs. Only a small subset of OR locations is sufficiently diverged from the others that clones derived from them behave as single-copy FISH probes. We estimate that duplications encompassing members of the OR gene family account for >0.1% of the human genome. A comparison of FISH signals at orthologous locations in other primates indicates that a portion of this OR 'subgenome' has been in flux during the divergence of primates, possibly as a mechanism for evolving the repertoire of olfactory receptors.

Stimulation of p53-mediated transcriptional activation by the p53-binding proteins, 53BP1 and 53BP2.

p53 is a tumor suppressor protein that controls cell proliferation by regulating the expression of growth control genes. In a previous study, we identified two proteins, 53BP1 and 53BP2, that are able to bind to wild type but not to mutant p53 via the DNA-binding domain of p53. We isolated cDNAs expressing a full-length human 53BP1 clone, which predicts a protein of 1972 residues that can be detected in the H358 human lung carcinoma cell line. The 53BP1 and 53BP2 genes were mapped to chromosomes 15q15-21 and 1q41-42, respectively. Immunofluorescence studies showed three types of staining patterns for 53BP1 as follows: both cytoplasmic and nuclear, homogeneous nuclear, and a nuclear dot pattern. In contrast, 53BP2 localized exclusively to the cytoplasm, and this pattern did not change upon coexpression of wild type p53. Although our previous study revealed that p53 is not able to bind simultaneously to either 53BP1 or 53BP2 and to DNA carrying a consensus binding site, both 53BP1 and 53BP2 enhanced p53-mediated transcriptional activation and induced the expression of a p53-dependent protein, suggesting that these proteins might function in signal transduction pathways to promote p53 activity.

Cloning and characterization of two Toll/Interleukin-1 receptor-like genes TIL3 and TIL4: evidence for a multi-gene receptor family in humans.

Remarkable structural and functional similarities exist between the Drosophila Toll/Cactus/Dorsal signaling pathway and the mammalian cytokine-mediated interleukin-1 receptor (IL-1R)/I-kappaB/NF-kappaB activation cascade. In addition to a role regulating dorsal-ventral polarity in the developing Drosophila embryo, signaling through Drosophila Toll (dToll) activates the nonclonal, or innate, immune response in the adult fly. Recent evidence indicates that a human homologue of the dToll protein participates in the regulation of both innate and adaptive human immunity through the activation of NF-kappaB and the expression of the NF-kappaB-controlled genes IL-1, IL-6, and IL-8, thus affirming the evolutionary conservation of this host defense pathway. We report here the cloning of two novel human genes, TIL3 and TIL4 (Toll/IL-1R-like-3, -4) that exhibit homology to both the leucine-rich repeat extracellular domains and the IL-1R-like intracellular domains of human and Drosophila Toll. Northern analysis showed distinctly different tissue distribution patterns with TIL3 expressed predominantly in ovary, peripheral blood leukocytes, and prostate, and TIL4 expressed primarily in peripheral blood leukocytes and spleen. Chromosomal mapping by fluorescence in situ hybridization localized the TIL3 gene to chromosome 1q41-42 and TIL4 to chromosome 4q31.3-32. Functional studies showed that both TIL3 and TIL4 are able to activate NF-kappaB, though in a cell type-dependent fashion. Together with human Toll, TIL3 and TIL4 encode a family of genes with conserved structural and functional features involved in immune modulation.

Mutations in the BRCA1-associated RING domain (BARD1) gene in primary breast, ovarian and uterine cancers.

Germline alterations of BRCA1 result in susceptibility to breast and ovarian cancer. The protein encoded by BRCA1 interacts in vivo with the BRCA1-associated RING domain (BARD1) protein. Accordingly, BARD1 is likely to be a critical factor in BRCA1-mediated tumor suppression and may also serve as a target for tumorigenic lesions in some human cancers. We have now determined the genomic structure of BARD1 and performed a mutational analysis of 58 ovarian tumors, 50 breast tumors and 60 uterine tumors. Seven polymorphisms were detected within the 2.34 kb coding sequence of BARD1 . Somatically acquired missense mutations were observed in one breast carcinoma and one endometrial tumor; in at least one of these cases, tumor formation was accompanied by loss of the wild-type BARD1 allele, following the paradigm for known tumor suppressor genes. In addition, a germline alteration of BARD1 was identified in a clear cell ovarian tumor (Gln564His); again, loss of the wild-type BARD1 allele was observed in the malignant cells of this patient. The Gln564His patient was also diagnosed with two other primary cancers: a synchronous lobular breast carcinoma and a stage IA clear cell endometrioid cancer confined to an endometrial polyp 6 years earlier. These findings suggest an occasional role for BARD1 mutations in the development of sporadic and hereditary tumors.

Members of the olfactory receptor gene family are contained in large blocks of DNA duplicated polymorphically near the ends of human chromosomes.

We have identified three new members of the olfactory receptor (OR) gene family within a large segment of DNA that is duplicated with high similarity near many human telomeres. This segment is present at 3q, 15q, and 19p in each of 45 unrelated humans sampled from various populations. Additional copies are present polymorphically at 11 other subtelomeric locations. The frequency with which the block is present at some locations varies among populations. While humans carry seven to 11 copies of the OR-containing block, it is located in chimpanzee and gorilla predominantly at a single site, which is not orthologous to any of the locations in the human genome. The observation that sequences flanking the OR-containing segment are duplicated on larger and different sets of chromosomes than the OR block itself demonstrates that the segment is part of a much larger, complex patchwork of subtelomeric duplications. The population analyses and structural results suggest the types of processes that have shaped these regions during evolution. From its sequence, one of the OR genes in this duplicated block appears to be potentially functional. Our findings raise the possibility that functional diversity in the OR family is generated in part through duplications and inter-chromosomal rearrangements of the DNA near human telomeres.