Digital imaging techniques in dermatology

Digital imaging is a versatile technique that has been infrequently used in dermatology to record visual images. We have used this technology for 10 patients to follow cutaneous lesions, including alopecia mucinosa, psoriasis, and dysplastic nevi. The setup included a personal computer, digitizer board, monitor, video camera, and lights. An introduction to electronic (digital) imaging is given and some of the many possible applications in dermatology are discussed.

The time-course of disease suppression and antibiosis by the ectomycorrhizal fungus Paxillus involutus

Seedlings of Pinus resinosa Ait. grown in test tubes were inoculated with the ectomycorrhizal fungus Paxillus involutus Fr. and, one day later, with a spore suspension of the root pathogenic fungus Fusarium oxysporum Schlecht emend, Sny. & Hans f.sp. pini. Controls consisted of seedlings inoculated with plugs of sterile modified Melin Norkrans medium and F. oxysporum. Seedling survival was counted, sporulation of F. oxysporum was measured, and ethanol extractions of the rhizosphere were made, 1, 2, 3, 4, 5, 6, 8, 10 and 14 d after inoculation with the pathogen. The ethanol extractives were concentrated and assayed for fungitoxic activity by measuring the germination of F. oxysporum microconidia. Dead seedlings were first observed 3 d after inoculation with the pathogen. Sporulation of F. oxysporum was reduced significantly 3 d after seedling inoculation with P. involutus when compared with controls lacking P. involutus. The fungitoxic activity of the rhizosphere of the seedlings inoculated with P. involutus was greater than the fungitoxic activity of the rhizosphere of control seedlings, increasing strongly 2.4 d after inoculation with the pathogen. Suppression of Fusarium root rot by P. involutus may, therefore, be the result of antibiosis by this ectomycorrhizal fungus.

The alcohol-impaired dentist: an educational challenge

A cross-sectional survey of 370 dental practitioners, a 74% response rate, was conducted and data collected. Prevailing attitudes within the dental profession toward the alcohol abuser and the role of peer intervention were recorded. Data collectively indicated a need for further strengthening educational efforts and the need for further development of a peer-assistance network.

Transverse membrane topography of the B875 light-harvesting polypeptides of wild-type Rhodobacter sphaeroides

Purified B875 light-harvesting complex, chromatophores, and spheroplast-derived vesicles from wild-type Rhodobacter sphaeroides were treated with proteinase K or trypsin, and the alpha and beta polypeptides were analyzed by electrophoretic, immunochemical, and protein-sequencing methods. With the purified complex, proteinase K digested both polypeptides and completely eliminated the A875 peak. Trypsin digested the alpha polypeptide and reduced the A875 by 50%. Proteinase K cleaved the beta polypeptide of chromatophores and the alpha polypeptide of spheroplast-derived vesicles. Sequence analyses of polypeptides extracted from proteinase K-treated chromatophores revealed that the beta polypeptide was cleaved between amino acids 4 and 5 from the N terminus. The N terminus of the alpha polypeptide was intact. We concluded that the N terminus of the beta polypeptide is exposed on the cytoplasmic membrane surface, and the difference in the digestion patterns between the spheroplast-derived vesicles and chromatophores suggested that the C terminus of the alpha polypeptide is exposed on the periplasmic surface.

Mycorrhizae and their potential use in the agricultural and forestry industries

Mycorrhizal fungi associated with plant roots increase the absorption of nutrients, particularly phosphorus, and thus enhance the growth of crop plants and trees. Vesicular-arbuscular mycorrhizae (VAM) occur in approximately 90% of all vascular plants including most of the important agricultural species, whereas ectomycorrhizae are found in most of the economically important tree species of the temperate regions of the world, and in some tropical trees. These symbiotic associations are, therefore, important in crop and biomass production. For this reason they are receiving considerable attention in agriculture and forestry. Currently, VAM are utilized in fumigated soils, greenhouse crops, and in the reclamation of disturbed sites. Ectomycorrhizae are employed in the establishment of trees in nurseries, in reforestation programs, and in the production of containerized seedlings. Production of VAM and ectomycorrhiza inoculum for large scale projects is now feasible but many basic questions related to persistence of these fungi in field situations, competition with other microorganisms, and particularly the most efficient fungi to use for particular hosts remain largely unanswered.

Cascade of Services Model and emotionally disabled students

The Cascade of Services Model has become an essential component of modern special education, but questions remain about how the Cascade actually operates and whether progams at different levels actually differ as presumed. The present study provides data relating to three areas of presumed differences between resource, self-contained, and residential programs serving emotionally disabled students: type or severity of students, amount of student integration, and allocation of teacher time. While the trends of the data indicate some validity for the assumptions implicit in the Cascade, differences between the levels of the Cascade may be overstated, and levels may overlap to the point where differences are inconsequential.

Embedding softened herbarium material in Spurr's resin for histological studies

Plant organs, including stems, rhizomes, leaves, roots, petals, sporangia and flower pedicels obtained from dried herbarium specimens of a variety of plant species have been softened with Aerosol OT and subsequently dehydrated in a graded series of acetones and embedded in Spurr's resin. Although the quality of preservation varied, sections of a variety of materials showed excellent cellular preservation. Sections stained through the resin with toluidine blue O and examined with either bright field microscopy or with crossed polarizers showed good cell detail. Histochemical tests for callose, polysaccharides, and cellulosic walls, using sections from which the resin had been removed by sodium methoxide and then viewed with an epifluorescence microscope, gave excellent results.

Gas-Chromatographic Determination of Ethylene Glycol in Serum

We have developed a method for detection and quantitation of ethylene glycol in serum, based on the gas chromatography of its dibenzoate ester. No special reagents or equipment are required. The method is virtually free of interference and sensitive to less than 0.02 mg of ethylene glycol per milliliter. The total analysis time is about 90 min.

The first known female of the African long-eared bat Laephotis wintoni (Vespertilionidae: Chiroptera)

A subadult Laephotis wintoni Thomas taken west of Mount Kenya in Kenya on 22 June, 1972, represents the fourth specimen and the first known female of that taxon. Measurements are compared with those of three males, and systematic relations within the genus are discussed. The soft palate is illustrated for the first time.

Xylem transfer cells in the rosette plant Hieracium floribundum

Xylem transfer cells in the rhizome of Hieracium floribundum are described for the first time and several methods used in visualizing these cells are discussed. The most marked wall ingrowths occur in transfer cells associated with the xylem of foliar traces.

The systematic status of the African molossid bats Tadarida bemmeleni and Tadarida cistura

Twenty-four specimens of Tadarida bemmeleni, collected in Cameroun in 1970, appear to be the first taken since the holotype was collected in 1875 from Liberia. Morphological comparisons with T. cistura from East Africa indicate that the two taxa are subspecies of the same species. Systematic relations, age, and sexual variation, as well as ecological notes, are provided. The facial features, caudal glands, palatal ridges, and cranial details are illustrated for the first time.

Ribonucleic acid synthesis in bacteria treated with toluene

Escherichia coli and Bacillus megaterium rendered permeable to ribonucleoside triphosphates by toluene treatment retain the capacity to synthesize discrete ribonucleic acid species.

The African molossid bat Tadarida russata

Five specimens of Tadarida russata obtained from Cameroun, West Africa, appear to be the first collected since the original series was obtained in 1910 from near Medje, Congo. Both the new and the original specimens were taken along the junction of the so-called "high forest" and "Guinea forest" zones but some 1200 miles apart. The Cameroun specimens were compared with the original type series and additional morphological data provided as well as the illustrations of facial and cranial features. T. bivittata, of similar size, is shown not to be closely allied with T. russata nor any member of the subgenus Chaerephon. T. russata is closely related to T. aloysiisabaudiae but differs in size, skull proportions, and details of the basisphenoid pits.

Formation of all stable RNA species in Escherichia coli by posttranscriptional modification

The kinetics of accumulation of the known stable RNA species (23S, 16S, and 5S rRNA and tRNA) in Escherichia coli C122 were monitored by polyacrylamide gel electrophoresis of purified cellular RNA, following termination of brief pulse labeling with (32)P-orthophosphate. Isotopically labeled stable RNA species appear only after a time lag, while total cellular RNA and the ostensible precursors to the stable RNA classes accumulate from the earliest times examined. It is concluded that all the known stable RNA species in E. coli are the products of posttranscriptional modification.