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Thomas Vogt

Publications and source records attributed to Thomas Vogt.

At least 73 records · Page 4Linked to original sources
PubMed2003

Recent advances in betalain research.

Betalains replace the anthocyanins in flowers and fruits of plants of most families of the Caryophyllales. Unexpectedly, they were also found in some higher fungi. Whereas the anthocyanin-analogous functions of betalains in flower and fruit colouration are obvious, their role in fungi remains obscure. The nature of newly identified betalains as well as final structure elucidation of earlier putatively described compounds published within the last decade is compiled in this report. Recent advances in research on betalain biosynthesis is also covered, including description of some 'early' reactions, i.e. betalain-specific dopa formation in plants and fungi and extradiolic dopa cleavage in fungi. Work on betalain-specific glucosyltransferases (GTs) has given new insights into the evolution of secondary plant enzymes. It is proposed that these GTs are phylogenetically related to flavonoid GTs. It was found that the decisive steps in betalain biosynthesis, i.e. condensation of the betalain chromophore betalamic acid with cyclo-dopa and amino acids or amines in the respective aldimine formation of the red-violet betacyanins and the yellow betaxanthins, are most likely to be non-enzymatic. Betalains have attracted workers in applied fields because of their use for food colouring and their antioxidant and radical scavenging properties for protection against certain oxidative stress-related disorders.

Acyltransferases↗
PubMed2003

Screening rarely screened women: time-to-service and 24-month outcomes of tailored interventions.

BACKGROUND: Managed care organizations and others reaching out to underscreened women seek strategies to encourage mammogram and Pap screening. METHODS: Female HMO members aged 50-69 years and overdue for a mammogram and a Pap test (n = 501) were followed for 24 months after interventions began. An Outreach intervention (tailored letters and motivational telephone interviews), an Inreach intervention (motivational interview delivered in clinics), and a Combined Inreach/Outreach intervention were compared to Usual Care at 24 months. Logistic regression and Cox hazard models examined predictors of obtaining screening services and time-to-service, respectively. RESULTS: Compared with Usual Care, the odds of Outreach women aged 50-64 obtaining a mammogram (OR = 2.06; 95% CI = 1.59-5.29), a Pap test (OR = 1.97; 95% CI = 1.12-3.53), or both (OR = 2.53; 95% CI = 1.40-4.63) remained significantly increased at 24 months. The average time-to-service for Outreach women was reduced by 4 months. Outreach effects persisted despite intensive, ongoing health plan efforts to improve screening of all women. CONCLUSIONS: This brief, tailored outreach intervention was an effective strategy for encouraging cervical and breast cancer screening among women overdue for both screening services. It also shortened time-to-service, an important benefit for early detection and treatment. Alternative strategies are needed for women who remain unscreened.

Aged↗
PubMed2003

A highly crystalline layered silicate with three-dimensionally microporous layers.

Layered silicates with three-dimensional microporosity within the layers have the potential to enable new applications in catalysis, adsorption and ion-exchange. Until now no such materials have been reported. However, here we present the synthesis and structure of AMH-3, a silicate with three-dimensionally microporous layers, obtained in high purity and crystallinity. AMH-3 is composed of silicate layers containing eight-membered rings in all three principal crystal directions, and spaced by strontium cations, sodium cations and water molecules. Because of its three-dimensional pore structure, acid and thermal stability, this layered material could find applications in polymer-silicate composites for membrane applications, for synthesis of combined microporous-mesoporous materials, and for the formation of new zeolites and microporous films. Its existence also opens new possibilities for the synthesis of other layered silicates with multidimensional microporous framework layers.

Cations↗
PubMed2003

[Porokeratotic eccrine ostial and dermal duct naevus (PEODDN)].

The porokeratotic eccrine ostial and dermal duct naevus or PEODDN represents a very rare hamartoma of the eccrine sweat glands. A 16-year old boy had developed subtle hyperkeratotic skin lesions on his right hallux at six months of age. When he was eight years old, he developed similar lesions on his right palm. Clinically the lesions were coniform hyperkeratoses. The histopathological examination confirmed the diagnosis of a PEODDN showing typical cornoid lamella where the eccrine secretory ducts penetrated the epidermis. Although porokeratotic eccrine ostial and dermal duct naevi are generally considered as unresponsive to conservative treatment, in our patient topical treatment with tazarotene gel 0.1% resulted in a significant improvement within three weeks.

Administration, Topical↗
PubMed2003

Bullous malignant melanoma: an unusual differential diagnosis of a hemorrhagic friction blister.

BACKGROUND: A 66-year-old woman presented to our outpatient clinic with a 3 x 2.5-cm tense, hemorrhagic-appearing bulla on her forefoot. Histopathology and immunohistochemistry confirmed a transtumoral-transepidermal blister formation within an advanced acrolentiginous malignant melanoma (MM). OBJECTIVE: To study bullous malignant melanoma. METHODS: Blistering in MMs represents a rare but clinically important pitfall in clinical differential diagnosis. The blisters are typically due to the disruption of the cohesion between neoplastic cells and keratinocytes, but physical friction may also contribute. RESULTS: Hemorrhagic blistering is, in many cases, a relatively insignificant finding in which frictional forces are imposed. CONCLUSION: The case reported here underscores that in rare cases MMs, particularly if acrally located, can be complicated by hemorrhagic blistering. Because of the life-threatening consequences, one should be aware of this rare differential diagnosis.

Aged↗
PubMed2003

Branched filaments no fungus, ovoid bodies no bacteria: Two unusual cases of mycetoma.

We describe a 58-year-old man presenting with necrotizing panniculitis of the lower right leg and a 64-year-old woman with a clinically similar lesion combined with pustular eruptions and subsequent ulceration on the forehead. In the first patient, Giemsa staining showed small ovoid bodies and Grocott staining revealed hyphae. Histology from the process on the forehead showed branched filaments in the periodic acid-Schiff (PAS) staining. In the first case, Madurella mycetomatis, a fungus, was the pathogenic agent, whereas in the other case white colonies of filamentous organisms resembling fungi could be cultivated that turned out to be the bacterium Nocardia brasiliensis. Since the initial clinical appearance of these two forms of mycetoma were almost identical and histopathologic findings were inconclusive, only sophisticated microbiologic work-up of material from lesional skin led to the correct diagnosis. In times of global tourism, these unusual cases impressively document the necessity to become more familiar with mycetoma to make accurate therapeutic decisions with effective results, possibly saving a limb.

Antifungal Agents↗
PubMed2003

Discrimination between gene expression patterns in the invasive margin and the tumour core of malignant melanomas.

Genes that determine the invasive capacity of the invasive front of malignant melanomas (MM) have not yet been systematically investigated in vivo. Therefore, we combined laser pressure catapulting (LPC) microdissection with cDNA microarray technology (DermArray, Research Genetics, representing about 5700 genes) to systematically analyse differences in gene expression profiles between the invasive margin and the tumour centre in nine cases of vertical growth phase MM. Signal-to-noise statistical algorithms combined with hierarchical clustering were performed to determine class-separating genes. The gene encoding phosphoenolpyruvate carboxykinase 1 (PEPCK), the Homo sapiens gene similar to Saccharomyces cerevisiae SSM4 (TEB4), the gene encoding ribosomal protein L19, the Homo sapiens gene similar to the Aspergillus nidulans SudD (a suppressor of the bimD6 homologue), the gene encoding the interleukin-3 receptor alpha subunit, the gene encoding the inositol 1,4,5-triphosphate 3-kinase isoenzyme, and three anonymous expressed sequence tags were identified as class-separating genes. These genes significantly discriminate between the invasive front and the tumour centre. Using this set of genes, 15 out of 18 LPC-dissected MM regions could be grouped correctly. We conclude that the candidate genes identified could spark further research on MM progression and may provide novel prognostic parameters.

Algorithms↗
PubMed2003

Orofacial granulomatosis as the initial presentation of Crohn's disease in an adolescent.

Orofacial granulomatosis (OFG) is a rare and heterogeneous clinical condition that presents with chronic swelling of the oral or facial tissues due to granulomatous inflammation. It is histologically characterized by noncaseating giant cell granulomata and epithelioid histiocytes. OFG includes the previously recognized clinical entities of Melkersson-Rosenthal syndrome and cheilitis granulomatosa (Miescher's cheilitis). A consistently effective medical treatment is not currently available. We describe an adolescent patient with a history of recurrent orofacial swelling preceding gastrointestinal symptoms by several years. He exhibited clinical and histological changes consistent with the diagnosis of OFG. It was resistant to standard therapies such as topical corticosteroids. Thorough history taking and clinical examination suggested Crohn's disease (CD), and further tests confirmed the diagnosis. The patient improved promptly after initiating oral treatment for CD with mesalazine and prednisolone. We conclude that OFG may be under- or misdiagnosed since the clinical manifestation may be misleading and its course is independent of or even preceding CD. Thus, patients with OFG should be asked about gastrointestinal symptoms consistent with CD. Those with suspicious symptoms should undergo a careful gastrointestinal evaluation, possibly including enteroclysis and complete gastrointestinal endoscopic examination, especially when the patient's history is conspicuous.

Adolescent↗
PubMed2003

Molecular genetic analysis excludes implantation metastasis of basal cell carcinomas.

Basal cell carcinoma (BCC) of the skin is the most common tumor in the white population. A 66-year-old man developed 2 BCCs at the left parietal region of the head and at the helix of the left ear. The 2 lesions matched exactly when pressing the ear against the head, suggesting an implantation metastasis mechanism. Molecular genetic techniques were used to confirm or exclude such a mechanism in this rare clinical constellation. Tumor tissues were precisely microdissected for DNA isolation. Exons 5-9 of the p53 tumor suppressor gene were directly sequenced. In addition, loss of heterozygosity analysis of chromosome 9q was performed using 5 polymorphic microsatellite markers. The BCC of the ear revealed a p53 mutation at codon 273, whereas the other one lacked this mutation. In addition, the smaller BCC of the ear showed loss of heterozygosity at 9q33.3, in contrast with the larger BCC. Interestingly, histologically normal skin of the ear distant from the small BCC had the same deletion, indicating a field defect of this skin patch at 9q33.3. Molecular genetic analysis clearly demonstrated different genetic alterations of the two BCCs and therefore most likely excludes a mechanism of implantation metastasis.

Aged↗
PubMed2003

Loss of EphB6 expression in metastatic melanoma.

Overexpression of various members of the Eph receptor tyrosine kinases and their ephrin ligands has been frequently reported in cancer. In contrast, a loss of EphB6 gene expression has been correlated with a poor prognosis in human neuroblastoma, suggesting a distinct role for this receptor compared to other family members. More recently, an important role of EphB6 signalling in T-cells has been described, suggesting possibly deleterious immunologic effects of a loss of EphB6 in cancer progression. We investigated the expression of EphB6 in melanocytic tumors. EphB6 mRNA of 22 microdissected tissues (7 benign nevi, 7 melanomas, 8 metastases) and 10 different cell lines (normal melanocytes, non-metastatic/metastatic melanoma cell lines) were measured by quantitative real-time RT-PCR. For visualization of EphB6 protein expression, immunohistochemistry of 32 melanocytic lesions were performed. On the mRNA level, the benign nevi revealed the highest EphB6 expression (mean = 1.43), while melanomas (mean = 0.63) and metastases (mean = 0.08; p=0.001) displayed a progressive and significant reduction of EphB6 expression. Accordingly, established melanoma cell lines with metastatic potential showed low EphB6 expression in comparison to normal melanocytes and to most of the melanoma cell lines. Immunohistochemistry revealed homogeneous staining in common nevi, whereas in malignant melanomas and metastases a heterogeneously positive to completely negative EphB6 staining was observed. Remarkably, Spitz nevi stained similarly to ordinary melanocytic nevi. Taken together, we show that melanoma progression to metastatic disease is associated with a significant reduction of EphB6 gene expression which may have considerable consequences for the prognosis of malignant melanoma patients and possible gene-therapeutic approaches.

Adolescent↗
PubMed2002

Non-framework cation migration and irreversible pressure-induced hydration in a zeolite.

Zeolites crystallize in a variety of three-dimensional structures in which oxygen atoms are shared between tetrahedra containing silicon and/or aluminium, thus yielding negatively charged tetrahedral frameworks that enclose cavities and pores of molecular dimensions occupied by charge-balancing metal cations and water molecules. Cation migration in the pores and changes in water content associated with concomitant relaxation of the framework have been observed in numerous variable-temperature studies, whereas the effects of hydrostatic pressure on the structure and properties of zeolites are less well explored. The zeolite sodium aluminosilicate natrolite was recently shown to undergo a volume expansion at pressures above 1.2 GPa as a result of reversible pressure-induced hydration; in contrast, a synthetic analogue, potassium gallosilicate natrolite, exhibited irreversible pressure-induced hydration with retention of the high-pressure phase at ambient conditions. Here we report the structure of the high-pressure recovered phase and contrast it with the high-pressure phase of the sodium aluminosilicate natrolite. Our findings show that the irreversible hydration behaviour is associated with a pronounced rearrangement of the non-framework metal ions, thus emphasizing that they can clearly have an important role in mediating the overall properties of zeolites.

Journal Article↗
PubMed2002

Structure of V(2)O(5)*nH(2)O xerogel solved by the atomic pair distribution function technique.

A long-standing issue regarding the local and long-range structure of V(2)O(5)*nH(2)O xerogel has been successfully addressed. The full three-dimensional structure of the lamellar turbostratic V(2)O(5)*nH(2)O xerogel was determined by the atomic pair distribution function technique. We show that on the atomic scale the slabs of the xerogel can be described well as almost perfect pairs (i.e., bilayers) of single V(2)O(5) layers made of square pyramidal VO(5) units. These slabs are separated by water molecules and stack along the z-axis of a monoclinic unit cell (space group C2/m) with parameters a = 11.722(3) A, b = 3.570(3) A, c = 11.520(3) A, and beta = 88.65 degrees. The stacking sequence shows signatures of turbostratic disorder and a structural coherence limited to 50 A.

Journal Article↗
PubMed2002

Pressure-induced volume expansion of zeolites in the natrolite family.

Powder diffraction patterns of the zeolites natrolite (Na(16)Al(16)Si(24)O(80).16H(2)O), mesolite (Na(5.33)Ca(5.33)Al(16)Si(24)O(80).21.33H(2)O), scolecite (Ca(8)Al(16)Si(24)O(80).24H(2)O), and a gallosilicate analogue of natrolite (K(16)Ga(16)Si(24)O(80).12H(2)O), all crystallizing with a natrolite framework topology, were measured as a function of pressure up to 5.0 GPa with use of a diamond-anvil cell and a 200 microm focused monochromatic synchrotron X-ray beam. Under the hydrostatic conditions mediated by an alcohol and water mixture, all these materials showed an abrupt volume expansion (ca. 2.5% in natrolite) between 0.8 and 1.5 GPa without altering the framework topology. Rietveld refinements using the data collected on natrolite show that the anomalous swelling is due to the selective sorption of water from the pressure-transmission fluid expanding the channels along the a- and b-unit cell axes. This gives rise to a "superhydrated" phase of natrolite with an approximate formula of Na(16)Al(16)Si(24)O(80).32H(2)O, which contains hydrogen-bonded helical water nanotubes along the channels. In mesolite, which at ambient pressure is composed of ordered layers of sodium- and calcium-containing channels in a 1:2 ratio along the b-axis, this anomalous swelling is accompanied by a loss of the superlattice reflections (b(mesolite) = 3b(natrolite)). This suggests a pressure-induced order-disorder transition involving the motions of sodium and calcium cations either through cross-channel diffusion or within the respective channels. The powder diffraction data of scolecite, a monoclinic analogue of natrolite where all sodium cations are substituted by calcium and water molecules, reveal a reversible pressure-induced partial amorphization under hydrostatic conditions. Unlike the 2-dimensional swelling observed in natrolite and mesolite, the volume expansion of the potassium gallosilicate natrolite is 3-dimensional and includes the lengthening of the channel axis. In addition, the expanded phase, stable at high pressure, is retained at ambient conditions after pressure is released. The unprecedented and intriguing high-pressure crystal chemistry of zeolites with the natrolite framework topology is discussed here relating the different types of volume expansion to superhydration.

Journal Article↗
PubMed2002

Substrate specificity and sequence analysis define a polyphyletic origin of betanidin 5- and 6-O-glucosyltransferase from Dorotheanthus bellidiformis.

Betanidin 6-O-glucosyltransferase (6-GT) is involved in the glycosylation of betacyanins, which replace the chromogenic anthocyanins as flower colorants in the Caryophyllales. The 6-GT cDNA was cloned from a cDNA library of Dorotheanthus bellidiformis (Burm. f.) N.E. Br., and the amino acid and nucleotide sequences were shown to be distinctly different from the corresponding betanidin 5-O-glucosyltransferase (5-GT) from the same plant species. Although both enzymes share very similar substrates, the proteins show only 19% amino acid sequence identity. In contrast, the protein sequence of the 6-GT showed significant identity to GTs from other species and may identify a new cluster of putative anthocyanidin GTs. Therefore, 6-GT and 5-GT apparently have evolved independently from ancestral glucosyltransferases involved in flavonoid biosynthesis.

Anthocyanins↗
PubMed2002

IgE-mediated anaphylactic reaction induced by succinate ester of methylprednisolone.

BACKGROUND: In systemic administration the prevalence of anaphylactic reactions attributable to corticosteroids is approximately 0.3%. Positive prick tests with different corticosteroids have been reported suggesting an immunoglobulin (Ig)E-mediated mechanism. OBJECTIVE: A 42-year-old man with multiple sclerosis developed flush, erythema, and itching a few minutes after the begin of an intravenous infusion of methylprednisolone-21-sodium succinate. DIAGNOSTIC AND RESULTS: Prick tests were found to be positive with methylprednisolone-21-sodium succinate and prednisolone-21-sodium succinate, whereas prick tests with prednisolone without ester and betamethasone-21-dihydrogen phosphate showed negative results. Oral challenge with prednisolone without ester and intravenous challenge with betamethasone-21-dihydrogen phosphate were well tolerated. Specific IgE-antibodies against methylprednisolone-21-sodium succinate were found in the serum of the patient. Because of the positive prick test and specific IgE antibodies against methylprednisolone-21-sodium succinate, the diagnosis of IgE-mediated anaphylactic reaction could be proven. Succinate ester was suspected to be immunogenic, as other corticosteroids without this particular ester or with other substitutions at the C21 remained negative both in the prick and the challenge tests. CONCLUSIONS: This patient showed an adverse reaction caused by methylprednisolone-21-sodium succinate. The uniqueness in this case was the presence of specific IgE antibodies against this esterified corticosteroid in the patient's serum proving that this reaction was based upon a true IgE-mediated mechanism.

Adult↗
PubMedDate not supplied

Cowpox and a cat.

Explore the source record for details and available documents.

Adolescent↗
PubMedDate not supplied

Follicular mycosis fungoides: variability of a rare entity.

OBJECTIVE: Three patients with follicular mycosis fungoides (FMF), a rare variant of folliculotropic cutaneous T-cell lymphoma, are discussed. Follicular involvement in cutaneous T-cell lymphoma commonly presents clinically with alopecia, follicular cysts, or comedo-like lesions usually associated with follicular mucinosis and strong epidermotropism. In contrast, FMF, in a strict sense, has been defined as a lymphocytic infiltration of hair follicles in the absence of both epidermal invasion and follicular mucin. DISCUSSION: Case 1 shows a clinically stable form of FMF characterized by circumscribed alopecia and its persistent resistance to topical therapeutic approaches. In contrast, Cases 2 and 3 demonstrate that classic mycosis fungoides lesions and FMF can occur simultaneously and that transitions occur from mycosis fungoides to FMF and vice versa. These observations strengthen the concept that FMF and mycosis fungoides represent just two variants of one entity of cutaneous T-cell lymphoma. In Case 3, rapid progression into tumor-stage mycosis fungoides and the follicular infiltration was controlled with bexarotene. CONCLUSIONS: Because it was previously suggested that FMF may have a worse prognosis compared with classic mycosis fungoides, this impressive response to bexarotene is of great clinical interest and may spark new studies employing this novel retinoid for FMF treatment.

Adult↗