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R Weller

Publications and source records attributed to R Weller.

At least 37 records · Page 2Linked to original sources
PubMed2000

16S rRNA-targeted oligonucleotide probes for the in situ detection of members of the phylum Cytophaga-Flavobacterium-Bacteroides.

Bacteria of the Cytophaga-Flavobacterium-Bacteroides phylum (CFB-phylum) are numerically important members of many microbial communities. A suite of five 16S rRNA-targeted oligonucleotide probes for members of this group is described which was designed to dominantly target bacteria of the CFB-phylum that are found in particular habitats. For this we initially performed a literature survey-for the sources and sites of isolation of hitherto described members of the CFB-phylum. Probe CFB286 is mostly complementary to the 16S rRNA of species originally isolated from freshwater habitats, however, detects some marine and soil isolates and is the only probe which includes some food isolates. Probe CFB563 detects marine as well as animal-associated isolates. Probe CFB719, which also detects some environmental isolates, and probe CFB972 are mostly targeting animal-associated isolates. All probes are complementary to a variety of human-associated species within the CFB-phylum which, in the data set investigated (October 1998), made up 46% of all 16S rRNA sequences from the CFB-phylum. We conclude that it is difficult to find habitat-specific probes for members of the CFB-phylum and that the design of probes for monophyletic groups should remain the standard approach. Applicability of the probes for fluorescence in situ hybridization and specificity for single cell detection were evaluated for the four mentioned probes whereas the fifth, probe CFB1082, which almost exclusively targets human-associated species, was not further characterized. The new probes are of limited determinative value and should be used together with the already established probes for the CFB-phylum. It is the hybridization pattern observed for a given cell or culture with the enlarged probe set that is suggestive for its affiliation with a defined group within the CFB-phylum.

Animals↗
PubMed2000

Functional cranial neuronavigation. Direct integration of fMRI and PET data.

OBJECTIVE: We report our first experiences with the direct integration of fMRI data into cranial neuronavigation. METHOD: For navigation we used the MKM system and thin-sliced T1 contrast enhanced images. As a first step 21 patients had fMRI for localization of the precentral gyrus, 2 patients for Broca area detection. By anatomical correlation, these functional data were indirectly compared to the intraoperative findings using cortical SSEP (n=20) or cortical stimulation (n=3). Encouraged by these preliminary results, we started the direct integration of fMRI into neuronavigation in June 1999, followed by PET in January 2000, enabling us to compare functional images with intraoperative findings directly. fMRI and PET data were integrated by landmark matching referring on skin fiducials. Meanwhile, fMRI data of 8 patients (6 motorcortex, 2 Broca) and PET images of 1 patient were directly integrated into neuronavigation. Six out of 8 patients had additional cortical monitoring, 2/8 were exclusively operated on by functional neuronavigation. RESULTS: Using indirect comparison between fMRI and intraoperative findings we observed a good correlation in every case for the motorcortex, but only in 1/2 for the speech area. In all 6 direct integrated fMRI cases, these findings corresponded well to the conventional ones. Both patients with sole functional navigation did not have any postoperative neurological deficit. The inaccuracy of the fMRI ifT1 matching was 2. 7 mm (sigma=0.9 mm) and 1.3 mm (sigma=0.4 mm) of the subsequent referenciation of the navigation. The tumor delinement shown by 11C-methionine PET could be proven by intraoperative biopsy outside its indicated tumor margin. The inaccuracy of the PET matching was 0. 8 mm. CONCLUSION: Functional neuronavigation enables to visualize and preserve relevant brain areas. Other functional areas like short-term memory, which solely can be detected by fMRI might also be monitored in the future. The integration of PET data expect to gain a better differentiation of tumor and edema.

Adult↗
PubMed1999

Comparison of radiography, scintigraphy and ultrasonography in the diagnosis of a case of temporomandibular joint arthropathy in a horse.

Diagnosis of temporomandibular joint disease in the horse presents a challenge to the equine veterinarian. This case report illustrates a combined imaging approach using radiography, scintigraphy and ultrasonography in a horse with severe arthropathy of the left temporomandibular joint. Radiographs were inconclusive. Scintigraphy with Tc99m methylenediphosphonate localised, but failed to characterise the disease process; ultrasonography was the only imaging method which both localised and characterised the lesion. Ultrasonography proved to be a relatively cheap, technically easy to perform and non-invasive method for the assessment of the disease.

Animals↗
PubMed1999

Bipolarity in children.

Childhood and adolescent bipolar disorder have been less studied than adult onset bipolar illness. However, case reports of mania in childhood can be found as early as the mid 19th century. Historically, several factors have made the accurate diagnosis of bipolar disorder in childhood difficult: clinical bias against the diagnosis of mania in children; low base rate of disorder; symptom overlap between bipolar disorder and other more prevalent childhood-onset psychiatric disorders; and developmental constraints and variability in clinical presentation. The epidemiology of juvenile-onset bipolar disorder remains an open topic for research. The disorder appears to increase in prevalence with advancing age until young adulthood. Reported phenomenology of bipolar disorder in children and adolescents indicates a highly variable presentation with a developmental trend towards increased resemblance to the adult phenotype with increasing age of onset. Diagnostic accuracy for the disorder is improved by adherence to diagnostic and statistical manual of mental disorders (DSM) criteria and may be aided by structured or semistructured diagnostic interviews. The course of bipolar disorder in children and adolescents has also received limited systematic study. However, research to date supports a clinical picture of a relapsing, recurrent illness with substantial morbidity. Systematic studies of pharmacologic treatments of acute mania in children and adolescents are limited in number and scope. Clinical justification for the use of acute antimanic treatments such as lithium and valproic acid is still based upon studies conducted in adults. There remains an immediate and significant need for additional research into all aspects of juvenile-onset bipolar disorder.

Adolescent↗
PubMed1999

The response of the microbial community of marine sediments to organic carbon input under anaerobic conditions.

Cyanobacterial biomass was added to anaerobic sediment to simulate the natural input of complex organic substrate that occurs in nature after algae blooms. Sediments were incubated at 0 degree C, 8 degrees C and 24 degrees C for 13 days. Community dynamics were measured by fluorescence in situ hybridisation (FISH), denaturing gradient gel electrophoresis (DGGE), and sequencing of 16S rDNA PCR products. Metabolic changes were followed by the analysis of total carbon mineralisation, sulfate reduction, and ammonium production rates. The addition of organic material resulted in significant changes in the composition of the microbial community at all temperatures tested. Sulfate reduction was the main mineralisation process detected. However, not sulfate-reducers but rather members of the Cytophaga-Flavobacterium phylogenetic cluster showed the highest increase in the bacterial cells as detected by FISH. We conclude that these organisms play an important role in the anaerobic decomposition of complex organic material perhaps because they are the main catalysts of macromolecule hydrolysis and fermentation. The molecular methods also indicated a stimulation of ribosome synthesis. The detection of a large number of rRNA-rich cells belonging to the Cytophaga-Flavobacterium phylogenetic cluster further supports the importance of their role in the degradation of complex organic material in anaerobic marine sediments. Their detection in high numbers in the field may indicate recent deposition events.

Anaerobiosis↗
PubMed1999

Psoriatic keratinocytes show reduced IRF-1 and STAT-1alpha activation in response to gamma-IFN.

Psoriasis is a chronic inflammatory dermatosis characterized by hyperproliferative keratinocytes (KC). The skin lesions are infiltrated by T cells, which secrete gamma interferon (gamma-IFN) and are believed to be necessary to maintain the psoriatic phenotype. In normal KC, gamma-IFN is a potent inhibitor of proliferation, but proliferation of KC persists in psoriatic plaques despite the presence of gamma-IFN. Immunostaining of interferon regulatory factor-1 (IRF-1) revealed that IRF-1 was localized to the basal cells of the epidermis in normal and in nonlesional psoriatic skin, but was suprabasal or completely absent in lesional psoriatic skin. This finding led to the hypothesis that abnormal signaling in the gamma-IFN pathway may occur in psoriatic KC. To test this hypothesis, we measured activation of IRF-1 and signal transducer and activator of transcription (STAT)-1alpha transcription factors in KC after stimulation with gamma-IFN. Primary cultures of KC from normal and nonlesional psoriatic skin were stimulated with gamma-IFN and subsequent transcription factor activation was measured by electrophoretic mobility shift assay. Psoriatic KC showed a reduced induction of IRF-1 and STAT-1alpha activation after stimulation with gamma-IFN, compared with normal KC. Reduced activation of IRF-1 and STAT-1alpha in response to gamma-IFN indicates a fundamental defect in the growth and differentiation control of psoriatic KC in the absence of the influence of other cell types.

Adult↗
PubMed1998

A randomized trial of acidified nitrite cream in the treatment of tinea pedis.

BACKGROUND: Nitric oxide is continually released from normal skin and has antimicrobial effects. An acidified nitrite cream releases supraphysiologic concentrations of nitric oxide and is fungicidal in vitro. OBJECTIVE: The purpose of this study was to assess the efficacy of an acidified nitrite cream as treatment for tinea pedis. METHODS: Sixty patients were recruited with both a clinical diagnosis of tinea pedis and hyphae identified on direct microscopy; they were randomly placed into an active group treated with twice-daily application of a mixture of 3% salicylic acid in aqueous cream and 3% nitrite in aqueous cream for 4 weeks and a control group treated with 3% salicylic acid in aqueous cream and aqueous cream alone. Nineteen patients completed the trial in the active group and 16 patients in the control group. Mycologic cure (negative results on microscopy and culture) and clinical improvement were measured at 0, 2, and 4 weeks and after a 2-week interval with no treatment. RESULTS: At the end of the treatment period, 18 of the 19 patients in the active group were mycologically cured as were 11 of 16 in the control group (p = 0.042). Two weeks after the cessation of treatment, 13 of 19 patients in the active group were mycologically cured and 5 of 16 in the control group (p = 0.028). The initial clinical scores in the active and control groups were 8.1 and 8.19 (two-tailed p = 0.95). At 4 weeks they were 1.66 and 6.0 (two-tailed p = 0.002) and after 2 weeks with no treatment 1.45 and 7.4 (two-tailed p < 0.0002). CONCLUSION: Acidified nitrite is effective therapy for tinea pedis.

Administration, Topical↗
PubMed1998

Tonsillitis and chronic psoriasis.

Although the relationship between streptococcal tonsillitis and acute guttate psoriasis is well recognized, its relationship to chronic forms of psoriasis is less established. In order to explore this further, the authors questioned 35 patients with severe psoriasis and 35 age-matched eczema controls about their history of significant sore throats (i.e. requiring a GP visit) and any resultant worsening of the skin condition. A third of the psoriasis patients reported recurrent sore throats which worsened their skin condition. This was true of only one (3%) of the 35 eczema controls. The authors discuss these findings in the context of recent laboratory work on the association between streptococcal infection and psoriasis.

Adult↗
PubMed1997

A comparison of subjective and objective measures of reduction of psoriasis with the use of ultrasound, reflectance colorimetry, computerized video image analysis, and nitric oxide production.

BACKGROUND: Studies of antipsoriatic therapy often rely on subjective scoring. Objective measures have been developed but have not previously been compared with subjective scoring. OBJECTIVE: Our purpose was to compare subjective and objective measures of reduction of psoriasis with topical therapy. METHODS: A 2-week, double-blind, left-to-right comparative trial of betamethasone valerate against white soft paraffin was performed in 12 patients. The subjective scores were erythema, elevation, scale, and a composite total. Objective measures were nitric oxide production measured by chemiluminescence; erythema reflectance; ultrasound scan for thickness, scale, and echo-poor zone; and computerized image analysis of video images. RESULTS: Subjective and objective measures had similar power to detect therapeutic effect. The subjective measures showed greater variation and relatively overestimated improvement. There was correlation between measures and estimates for area, redness, and thickness. Nitric oxide production was the most powerful objective measure. CONCLUSION: Thickness determined by ultrasound scan and nitric oxide production are useful measures of reduction of psoriasis, which lend themselves to more powerful statistical tests than subjective interval data.

Administration, Topical↗