Powered endonasal dacryocystorhinostomy: technique and results of a series of patients.

INTRODUCTION: External dacryocystorhinostomy (DCR) has been the gold standard for treatment of epiphora. Currently several endoscopic DCR techniques are described. We evaluated results of endonasal DCR in our institution. METHODS: A retrospective chart review of a consecutive series of DCR procedures. Patients were subjected to a questionnaire a minimum of 6 months postoperatively to assess longer-term results. RESULTS: 19 DCR procedures in 16 patients (6 males) by a single surgeon (LD) were reviewed. Mean age was 60 (range 32 - 79). All patients suffered from epiphora (4-60 months), 7 had recurrent dacryocystitis. The technique involved the creation of a large rhinostomy using a microdebrider with a rough diamond burr and apposition of nasal mucosal and lacrimal sac flaps with Gelfoam. A silicone tube was placed in the nasolacrimal system. Patients were discharged day 1 and all patients reported immediate improvement of symptoms. Postoperative complications were limited to epistaxis in one patient. Patients were seen at week 1, 3 and 6 at clinic to perform suction cleaning until complete internal healing. The silicone tube was removed (at the last but one visit) after a median of 15 weeks (range 9-26 weeks) postoperatively. After a median follow-up of 19 months 13 patients were completely symptom free. Two patients reported minor symptoms sporadically. One patient reported recurrence of symptoms. CONCLUSION: Powered endonasal DCR with internal marsupialisation of the lacrimal sac is a safe and successful procedure for the treatment of nasolacrimal duct obstruction.

Diagnosis of isolated sphenoid lesions.

Isolated lesions of the sphenoid sinus are rare, and diagnosis is difficult because of the non-specific symptoms and clinical signs. The pathology of these lesions can be divided into three groups: inflammatory lesions, tumoural lesions, and a small group of so-called miscellaneous lesions. In a retrospective study, we evaluated the diagnosis and underlying pathology of 49 consecutive isolated sphenoid lesions all subjected to diagnostic and/or therapeutic endoscopic sinus surgery. The diagnosis of isolated sphenoid lesions based on clinical history and clinical examination, including nasal endoscopy, was not reliable because of the non-specific symptoms and clinical signs. A definitive diagnosis could be made only by radiological imaging and/or surgical exploration. The largest group of patients suffered from inflammatory lesions (29 patients), followed by tumoural lesions in 17 patients. Two patients had a sphenoidal cerebrospinal fluid leak, and one patient had a cholesterol granuloma. The outcome for patients who underwent a therapeutic endoscopic surgical procedure was favorable in 22% and perfect in 67%. There were no complications during or after endoscopic surgery.

An AFLP-based genome-wide mapping strategy.

To efficiently determine the chromosomal location of phenotypic mutants, we designed a genome-wide mapping strategy that can be used in any crop for which a dense AFLP (Amplified Fragment Length Polymorphism) map is available or can be made. The AFLP technique is particularly suitable to initiate map-based cloning projects because it detects many markers per reaction. First a standard set of AFLP primer combinations that results in a framework of AFLP markers well dispersed over the genome is selected. These primer combinations are applied to a limited number of mutant individuals from a segregating population to register linkage and non-linkage of the AFLP markers to the gene-of-interest. Further delineation of the area of interest is accomplished by analyzing the remaining recombinants and additional mutant individuals with AFLP markers that lie within the identified region. We illustrate the usefulness of the method by mapping three rotunda ( ron) leaf-form mutant loci of Arabidopsis thaliana and show that in the initial phase of map-based cloning projects a 400-600 kb interval can be identified for the average mutant locus within a few weeks. Once such an area is identified and before initiating the more time-consuming fine-mapping procedure, it is essential to examine publicly available databases for candidate genes and known mutants in the identified region. The 390-kb interval on chromosome 4 that harbors the ron2 mutation, also carries a known flower mutant, leunig ( lug); upon crossing, the two mutants appeared to be allelic. When no such candidates are found, the mapping procedure should be continued. We present a strategy to efficiently select recombinants that can be used for fine mapping.

A physical amplified fragment-length polymorphism map of Arabidopsis.

We have positioned amplified fragment-length polymorphism (AFLP) markers directly on the genome sequence of a complex organism, Arabidopsis, by combining gel-based AFLP analysis with in silico restriction fragment analysis using the published genome sequence. For placement of the markers, we used information on restriction fragment size, four selective nucleotides, and the rough genetic position of the markers as deduced from the analysis of a limited number of Columbia (Col)/Landsberg (Ler) recombinant inbred lines. This approach allows for exact physical positioning of markers as opposed to the statistical localization resulting from traditional genetic mapping procedures. In addition, it is fast because no extensive segregation analysis is needed. In principle, the method can be applied to all organisms for which a complete or nearly complete genome sequence is available. We have located 1,267 AFLP Col/Ler markers resulting from 256 SacI+2, MseI+2 primer combinations to a physical position on the Arabidopsis genome. The positioning was verified by sequence analysis of 70 markers and by segregation analysis of two leaf-form mutants. Approximately 50% of the mapped Col/Ler AFLP markers can be used for segregation analysis in Col/C24, Col/Wassilewskija, or Col/Cape Verde Islands crosses. We present data on one such cross: the localization of a viviparous-like mutant segregating in a Col/C24 cross.

Evidence for an ancient chromosomal duplication in Arabidopsis thaliana by sequencing and analyzing a 400-kb contig at the APETALA2 locus on chromosome 4.

As part of the European Scientists Sequencing Arabidopsis program, a contiguous region (396607 bp) located on chromosome 4 around the APETALA2 gene was sequenced. Analysis of the sequence and comparison to public databases predicts 103 genes in this area, which represents a gene density of one gene per 3.85 kb. Almost half of the genes show no significant homology to known database entries. In addition, the first 45 kb of the contig, which covers 11 genes, is similar to a region on chromosome 2, as far as coding sequences are concerned. This observation indicates that ancient duplications of large pieces of DNA have occurred in Arabidopsis.

Sequence analysis of a 40-kb Arabidopsis thaliana genomic region located at the top of chromosome 1.

As a contribution to the European Scientists Sequencing Arabidopsis (BIOTECH ESSA) project, a contig of almost 40kb has been sequenced at the extreme top of chromosome 1, around the Arabidopsis thaliana gene coding for a member of the 1-aminocyclopropane-1-carboxylate synthesis gene family. The region contains, besides the ACS1 gene itself, 10 putative genes, all new for Arabidopsis. Among these are three genes encoding kinases, a late embryogenesis-abundant protein, a MADS box-containing protein, a dehydrogenase, and a Myb-related transcription factor. In addition, six cDNAs have been sequenced that correspond to this region.

Sequence analysis of a 24-kb contiguous genomic region at the Arabidopsis thaliana PFL locus on chromosome 1.

As part of the European Union program of European Scientist Sequencing Arabidopsis (ESSA), the DNA sequence of a 24.053-bp insert of cosmid clone CC17J13 was determined. The cosmid is located on chromosome 1 at the PFL locus (position 30 cM). Analysis of the sequence and comparison to public databases predicts seven genes in this area, thus approximately one gene every 3.3 kb. Three cDNAs corresponding to genes in this region were also sequenced. The homologies and/or possible functions of the (putative) genes are discussed. Proteins encoded by genes in this region include a polyadenylate-binding protein (PAB-3) and a GTP-binding protein (Rab7) as well as a novel protein, possibly involved in double-stranded RNA unwinding and apoptosis. Intriguingly, the gene encoding the PAB-3 protein, which is very specifically expressed, is flanked by putative matrix attachment regions.