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Biomedical subjects

J Dabrowski

Publications and source records attributed to J Dabrowski.

At least 109 records · Page 6Linked to original sources
PubMed1980

Preliminary results of J-resolved, two-dimensional 1H-NMR studies on glycosphingolipids.

Homonuclear J-resolved two-dimensional spectroscopy has been applied to the simplest glycosphingolipid, glycosylceramide. In comparison with the conventional one-dimensional spectrum, the possible advantages and shortcomings of the two-dimensional method as applied to blood-group-active glycosphingolipids consisting of several saccharide units, have been pr esented. As an example, preliminary results on a more complex pentaosylceramide (IV3Gal-alpha-neolactotetraosylceramide) are discussed.

Animals↗
PubMed1980

2,3-trans-3,4-trans-3,4-Dihydroxy-L-proline: An amino acid in toxic peptides of Amanita virosa mushrooms.

Among the four possible stereoisomers of 3,4-dihydroxy-L-proline,2,3-trans-3,4-trans-3,4-dihydroxy-L-proline (IV) had not been found in nature previously. It has now been detected as a component of virotoxins, toxic peptides of Amanita virosa mushrooms. Because periodate failed to effect an oxidative glycol splitting reaction, the two hydroxyl groups in positions 3 and 4 were expected to be in a trans configuration. Furthermore, the formation of a 4-lactone on treatment with acids pointed to the carboxyl group and the hydroxyl group at position 4 being in a cis configuration. These results are in agreement with structure IV only. Final proof for structure IV was given by NMR spectroscopy and direct comparison with the 2,3-cis-3,4-trans-3,4-dihydroxy-L-proline isomer.

Journal Article↗
PubMed1979

Immunoelectron microscopic studies in IgA linear dermatosis.

The authors investigated three cases of IgA linear dermatosis by immunoelectron microscopy. In two of the cases there were additionally some IgG deposits in the basement membrane zone. The arrangement of the IgA deposits was found to vary. In two cases it was of the dermal and the lamina lucida type at the same time, and in one case it was so close to basal cell membranes as to leave an electronlucent space on the side facing the basal lamina. In the third case, the arrangement (only IgG and complement were studied) was exclusively of the dermal type. In one of the cases the deposits had first, i.e., 1 1/2 years earlier, been confined to the lamina lucida, whereas now they were also seen below the basal lamina, although the clinical condition of the patient had remained unchanged. It would seem that the localization of IgA deposits in the basement membrane zone may vary, depending on the evolution of the disease.

Adult↗
PubMed1979

[Methodological hints on the gas chromatographic determination of kelevan and kepone in potatoes, potato foliage and soil].

The gas chromatographic determination of Kelevan, an ethyllaevulinic acid derivative of Kepone, requires its conversion to Kepone. Thermal decomposition in the injection block of the gas chromatograph at 45 degrees C. has proved to be well suited for routine work. The sample is extracted with acetonitrile; the extract is purified and concentrated under reduced pressure. The separation of Kelevan from Kepone already metabolically produced is possible by column chromatography (silica gel; elution with benzene and 5% acetone in benzene). The determination of pre-existent Kepone and of Kelevan (after thermal conversion to Kepone) was achieved by means of a Pye-Unicam gas chromatograph. The limits of detection are 0.002 p.p.m. for Kepone, and 0.003 p.p.m. for Kelevan. The recovery of Kelevan and Kepone added to control samples (for every 10 determinations with different amounts added to potatoes, potato foliage and soil samples) ranges from 63 to 88%; the standard derivation, from +/- 1.7 to 7.3%.

Chlordecone↗
PubMed1979

The ultrastructural localization of IgA deposits in chronic bullous disease of childhood (CBDC).

A case of bullous disease in a child with linear IgA immune deposits at the basement membrane zone and with some clinical, histological, and electron microscopic characteristics both of dermatitis herpetiformis and bullous pemphigoid, is described. The bulla formed between the basal lamina and basal cell membranes as in bullous pemphigoid, but at the same time there were numerous inflammatory cells in the dermis just below the partly destroyed basal lamina and also abundant fibrin deposits in very recent bulla and in the skin, all of which is rather characteristic of dermatitis herpetiformis. Ultrastructurally, the IgA deposits were located chiefly below the lamina basalis (the dermal type) but also, though less abundantly, in the lamina lucida, very much as we have seen them to be in adult cases with linear IgA immune deposits at the basement membrane zone. The investigations have supplied further evidence showing the chronic bullous disease of childhood to be actually a counterpart of the form in adults with the same linear localization of IgA deposits.

Child, Preschool↗
PubMed1978

The ultrastructural localization of IgA in skin of a patient with mixed form of dermatitis herpetiformis and bullous pemphigoid.

A case with mixed features of dermatitis herpetiformis and bullous pemphigoid was investigated by immuno-electron microscopy. There were clinical, histological, and ultrastructural characteristics of both diseases, the response to sulfapyridine was dramatic at the beginning, but intestinal lesions were absent. Direct immunofluorescence tests were made 6 times in the 4 year period and demonstrated in all biopsies exclusively linear IgA deposits. The IgA deposits were shown to occupy the entire lamina lucida and to adhere to the basal cell membranes and lamina densa, very much like IgG deposits in bullous pemphigoid. Antibodies against the basement membrane zone could not be demonstrated in the serum.

Basement Membrane↗
PubMed1977

Electron microscopic studies in dermatitis herpetiformis in relation to the pattern of immune deposits in the skin.

Electron microscopic studies were made in 12 cases of dermatitis herpetiformis: 6 of them with a continuous immunofluorescence line of IgA deposits at the dermo-epidermal junction, and the other 6 with granular IgA deposits in the dermal papillae. Six cases of bullous pemphigoid with a continuous immunofluorescence line of IgG deposits at the dermo-epidermal junction were examined similarly for comparison. In dermatitis herpetiformis with the continuous IgA line the ultrastructural characteristics both of dermatitis herpetiformis and bullous pemphigoid were present, even when the histological and clinical features as well as response to sulphapyridine and sulphones were typical of dermatitis herpetiformis. The ultrastructural pattern was essentially the same as in the cases with clinical and histological characteristics of the mixed dermatitis herpetiformis-bullous pemphigoid form, although in the latter there was some predominance of the characteristics of bullous pemphigoid.

Dermatitis Herpetiformis↗
PubMed1976

Smallpox today.

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Humans↗
PubMed1975

Studies on the role of C-type viruses in the development of epithelial tumors induced with DMBA.

Epithelial tumors were induced using 0.5 per cent solution of DMBA in two strains of mice--one infected with leukoviruses (Swiss mice), and the other is free of these viruses (hairless mice). Tumors from 15 mice of each strain were examined light- and electron-microscopically. Depending on the period of administration of the carcinogen, benign growths of the type of papilloma or keratoacanthoma were obtained, or malignant tumors. In the tumors in Swiss mice electron microscopy revealed a distinct increase in the numbers of viruses in comparison with surrounding skin and intact skin of healthy mice of this strain. In spite of certain histologic differences between tumors produced in Swiss and hairless mice, the results argue against a role of leukoviruses in the pathogenesis of experimentally induced epithelial tumors in mice.

9,10-Dimethyl-1,2-benzanthracene↗