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H J Ditton

Publications and source records attributed to H J Ditton.

11 recordsLinked to original sources
PubMed2004

The AZFa gene DBY (DDX3Y) is widely transcribed but the protein is limited to the male germ cells by translation control.

We explored the function of the human DEAD-box Y RNA helicase DBY (DDX3Y) gene located in the (AZFa) region on the human Y chromosome (Yq11.21). Deletion of this Y interval is known to be a major cause for the occurrence of a severe testicular pathology, the Sertoli-cell-only (SCO) syndrome. DBY has a structural homologue on the short arm of the X chromosome DBX (DDX3X) (Xp11.4). We found widespread transcription of both genes in each tissue analyzed, although predominantly in testis tissue. However, translation of DBY was detected only in the male germ line, whereas DBX protein was expressed in all tissues analyzed. In testis tissue sections, DBY protein was found predominantly in spermatogonia, whereas DBX protein was expressed after meiosis in spermatids. We conclude that although both RNA helicases are structurally very similar, they have diverged functionally to fulfill different roles in the RNA metabolism of human spermatogenesis, and that deletion of the DBY gene is the most likely cause of the severe testicular pathology observed in men with AZFa deletions.

Chromosomes, Human, Y↗
PubMed1998

Environmental occurrence of the Whipple's disease bacterium (Tropheryma whippelii).

Whipple's disease is a systemic disorder in which a gram-positive rod-shaped bacterium is constantly present in infected tissues. After numerous unsuccessful attempts to culture this bacterium, it was eventually characterized by 16S rRNA gene analysis to be a member of the actinomycetes. The name Tropheryma whippelii was proposed. Until now, the bacterium has only been found in infected human tissues, but there is no evidence for human-to-human transmission. Here we report the detection of DNA specific for the Whipple's disease bacterium in 25 of 38 wastewater samples from five different sewage treatment plants in the area of Heidelberg, Germany. These findings provide the first evidence that T. whippelii occurs in the environment, within a polymicrobial community. This is in accordance with the phylogenetic relationship of this bacterium as well as with known epidemiological aspects of Whipple's disease. Our data argue for an environmental source for infection with the Whipple's disease bacterium.

Actinobacteria↗
PubMed1997

Whipple's disease: staging and monitoring by cytology and polymerase chain reaction analysis of cerebrospinal fluid.

BACKGROUND & AIMS: Diagnostic procedures in Whipple's disease usually focus on the intestine, but symptomatic central nervous system involvement is a major threat for patients. The aim of this study was to determine the diagnostic value of cerebrospinal fluid (CSF) analysis. METHODS: A total of 39 CSF samples and 2 brain biopsy specimens that were obtained from 24 patients with Whipple's disease at various intervals after diagnosis were examined. Five patients presented with neurological symptoms, 3 of them as relapses after therapy. Thirty-two CSF samples were examined by polymerase chain reaction for Tropheryma whippelli and 20 CSF samples by cytology. Brain biopsy specimens were examined histologically. RESULTS: Positive results were obtained in 4 of 5 patients (80%) with neurological symptoms, in 7 of 10 patients (70%) without neurological symptoms examined before therapy, and in 3 of 11 patients (27%) without neurological symptoms studied during or after therapy. Conversion from positive to negative was observed in 4 patients after antibiotic treatment. CONCLUSIONS: Testing of CSF in Whipple's disease yields a high rate of positive results, even in patients without neurological symptoms. Examination of CSF is therefore potentially useful for initial staging and for monitoring of the efficiency of therapy.

Actinobacteria↗
PubMed1997

Epidemiology of Whipple's disease in Germany. Analysis of 110 patients diagnosed in 1965-95.

BACKGROUND: The epidemiology of Whipple's disease (WD) is obscure. To obtain basic data, we performed an evaluation of WD patients in Germany. METHODS: Information was collected from 110 WD patients diagnosed during 1965-95 at 5 institutions in different regions of Germany. Four items were evaluated: 1) year in which the diagnosis was made; 2) residence and 3) age at the time of diagnosis; and 4) sex. RESULTS: WD patients originated from all parts of Germany. The incidence of new cases was relatively stable, with a mean of one to two cases per year per collecting centre. In 1995, a maximum of 13 new WD patients was diagnosed. There was a significant increase in the mean age of patients (1965-75, 48.7 years; confidence interval, +/- 3.98 years; 1976-85, 50.7 years, +/- 3.69 years; 1986-95, 57.0 years, +/- 2.80 years; P < 0.01) and an increasing proportion of women (1965-85, 4%; 1986-1995, 22%). CONCLUSIONS: Whipple's disease is not quite as rare as commonly assumed. There is no obvious geographic predominance. During the past three decades, the demography of WD patients has changed.

Adult↗
PubMed1996

Histology of intestinal Whipple's disease revisited. A study of 48 patients.

Whipple's disease is an infectious disorder with intestinal and extra-intestinal manifestations. We reinvestigated the intestinal histology in a series of 48 patients (10 females, 38 males; mean age 56.5 years, standard deviation of the mean +/- 11.2 years). A total of 126 biopsy samples, obtained prior to, during, and after therapy, were evaluated by light microscopy. In 43 patients (90%), histology was consistent with common descriptions, while it was uncommon in 3 patients (6%), and non-diagnostic in 2 patients (4%). During treatment, several alterations occurred. Apart from a continuous decrease in PAS-positive macrophages, the pattern of mucosal infiltration changed from diffuse to patchy. Moreover, the cytological aspects of PAS-positive macrophages changed substantially, and this change was used to propose four different subtypes. Initially, subtype 1 macrophages predominated (74%), but showed a gradual decrease within a few months of therapy. After 15 months, subtype 3 and subtype 4 macrophages predominated (< 80%). In 7 of 9 patients followed over long periods some subtype 3 or subtype 4 macrophages persisted. It is concluded that at diagnosis and during treatment the intestinal histology of Whipple's disease is heterogeneous. A few PAS-positive macrophages commonly persist at long-term follow-up. This and other features suggest the presence of a persistent immune defect.

Animals↗
PubMed1996

Diagnostic application of a polymerase chain reaction assay for the Whipple's disease bacterium to intestinal biopsies.

BACKGROUND & AIMS: The uncultured Whipple's disease bacterium (Tropheryma whippelii) was characterized in 1991-1992 by polymerase chain reaction (PCR) and sequencing of the bacterial 16S ribosomal RNA gene. The aim of this study was to develop a PCR assay for diagnostic purposes. METHODS: Modified primers for PCR and a specific probe for hybridization were designed. The specificity of this PCR assay was tested using 37 bacterial control strains and intestinal biopsy samples from 16 patients without Whipple's disease. The sensitivity was tested in 88 intestinal biopsy samples from 35 patients with Whipple's disease. RESULTS: PCR and hybridization were negative in all 37 bacterial controls and in all 16 patients without Whipple's disease. Before therapy, DNA of T. whippelii was detected in all 30 patients with Whipple's disease from whom formalin-fixed biopsy material was available, whereas Bouin-fixed material was negative. During and after treatment, PCR was negative in 23 of the 24 patients who were followed up. Generally, conversion to negative occurred within 1 year. Despite negative intestinal PCR, symptomatic cerebral Whipple's disease appeared in 3 patients. CONCLUSIONS: This PCR assay is specific and sensitive and is applicable as a diagnostic test. However, PCR from intestinal biopsy samples seems less helpful for monitoring the effect of treatment.

Actinobacteria↗
PubMed1996

Reassessment of the phylogenetic position of the bacterium associated with Whipple's disease and determination of the 16S-23S ribosomal intergenic spacer sequence.

Whipple's disease is a rare chronic illness associated with an unculturable bacterium that is constantly present in affected tissues. This bacterium was previously characterized at the molecular level by PCR and sequencing of the 16S rRNA gene. On the basis of 1,321 nucleotides of the sequence of its gene coding for 16S rRNA (16S rDNA), a phylogenetic relationship to the actinomycetes was established. In this study, we determined an almost complete 16S rDNA sequence (1,495 nucleotides), the 16S-23S ribosomal intergenic spacer sequence, and 200 nucleotides of the 23S rRNA gene. The 16S rDNA sequence was compared with the large number of actinomycete sequences that have been added to the database since the original study. Phylogenetic analysis revealed a branching position as the deepest branch of the cluster comprising the actinomycetes with group B peptidoglycan between this group and the family Cellulomonadaceae. This provides additional information on the phylogenetic position of this bacterium and some clues as to its characteristics. The spacer region between the 16S and 23S rRNA genes is 294 nucleotides long and does not contain tRNA genes. As has been shown in other instances, the increased variability of the ribosomal intergenic spacer compared with the 16S rRNA gene makes it a potential target for use in the differentiation of strains of the bacterium associated with Whipple's disease.

Actinomycetales↗
PubMed1994

Characterization of contaminating DNA in Taq polymerase which occurs during amplification with a primer set for Legionella 5S ribosomal RNA.

An amplification product that occurred in negative controls of a PCR using a primer system for Legionella 55 ribosomal RNA was characterized by direct sequencing. The amplification product did not hybridize to a Legionella specific oligonucleotide. It was derived from bacterial DNA contaminating Taq DNA polymerase, a phenomenon that was previously reported for amplification reactions with universal primer sets for bacterial 16S rRNA. The sequence of the 5S ribosomal fragment had close homology to the 5S-rRNA of the species Pseudomonas fluorescens, Pseudomonas aeruginosa, Alcaligenes faecalis, and Azotobacter vinelandii. These findings confirm that the DNA contaminations in Taq DNA polymerase belong to other species than Thermus aquaticus or Escherichia coli.

Base Sequence↗
PubMed1992

Evidence that Borrelia burgdorferi immunodominant proteins p100, p94 and p83 are identical.

Recently there have been reports on high-molecular mass components of Borrelia burgdorferi, namely the p100, p94 and p83, which claimed these proteins to be specific marker antigens for the serodiagnosis of late Lyme borreliosis. The nucleotide sequences of the p100 and p83 have been published. The alignment of the deduced N-terminal amino acid sequences with the N-terminal sequence of the p94 now provides evidence that all three proteins are identical.

Amino Acid Sequence↗