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PubMed2002

Chitosan as an edible invisible film for quality preservation of herring and atlantic cod.

The effect of chitosan with different molecular weights as coatings for shelf-life extension of fresh fillets of Atlantic cod (Gadus morhua) and herring (Clupea harengus) was evaluated over a 12-day storage at refrigerated temperature (4 +/- 1 degrees C). Three chitosan preparations from snow crab (Chinoecetes opilio) processing wastes, differing in viscosities and molecular weights, were prepared; their apparent viscosities (360, 57, and 14 cP) depended on the deacetylation time (4, 10, and 20 h, respectively) of the chitin precursor. Upon coating with chitosans, a significant (p < or = 0.05) reduction in relative moisture losses of 37, 29, 29, 40, and 32% was observed for cod samples coated with 360 cP chitosan after 4, 6, 8, 10, and 12 days of storage, respectively. Chitosan coating significantly (p < or = 0.05) reduced lipid oxidation as displayed in peroxide value, conjugated dienes, 2-thiobarbituric acid reactive substances and headspace volatiles, chemical spoilage as reflected in total volatile basic nitrogen, trimethylamine, and hypoxanthine, and growth of microorganisms as reflected in total plate count in both fish model systems compared to uncoated samples. The preservative efficacy and the viscosity of chitosan were inter-related; the efficacy of chitosans with viscosities of 57 and 360 cP was superior to that of chitosan with a 14 cP viscosity. Thus, chitosan as edible coating would enhance the quality of seafoods during storage.

Animals↗
PubMed2004

1,3-beta-glucan quantification by a fluorescence microassay and analysis of its distribution in foods.

The objective of this study was to establish analytical approaches to quantify 1,3-beta-glucan (1,3-beta-G) in foods. Six food categories including legumes, cereals, tubers, vegetables, fruits, and mushrooms and 17 total items were tested. An extraction procedure was designed to prepare food cold-water soluble, hot-water soluble, cold-alkaline soluble, and hot-alkaline soluble fractions. A fluorescence microassay based on aniline blue dye, which bound specifically to 1,3-beta-G, was developed to measure its content in the food fractions. Curdlan was used as standard to construct the 1,3-beta-G calibration curve, and a linear correlation within a 14 microg/mL concentration range was obtained. This microassay displayed selectivities among various 1,3-beta-G species. Biologically active ones such as pachyman and yeast glucan possessed much stronger fluorescent signals than others such as laminarin and barley glucan. Possible fluorescent interference from food proteins was estimated. This assay tolerated up to 50% of bovine serum albumin in 10 microg/mL curdlan. Analysis of the four food fractions showed that besides the well-known lentinan-containing shiitake, popular foods such as celery, chin-chian leaves, carrot, and radish contained nearly 20% 1,3-beta-G in their total sugar. Soybean dry weight contained 0.8% 1,3-beta-G, which was twice the amount compared to shiitake. Snow mushroom dry weight had the highest 1,3-beta-G content, at 2.5%, and was rich in both water (0.67%) and alkaline soluble (1.87%) forms. In conclusion, this dye-binding fluorescence microassay in conjunction with the extraction procedure can be applied in the prescreening of potential foods rich in functional 1,3-beta-G.

Aniline Compounds↗
PubMed2006

The kinetics of H2O vapor condensation and evaporation on different types of ice in the range 130-210 K.

The kinetics of condensation (kc) and the evaporation flux (J(ev)) of H2O on ice were studied in the range 130-210 K using pulsed-valve and steady-state techniques in a low-pressure flow reactor. The uptake coefficient gamma was measured for different types of ice, namely, condensed (C), bulk (B), single crystal (SC), snow (S), and cubic ice (K). The negative temperature dependence of gamma for C, B, SC, and S ice reveals a precursor-mediated adsorption/desorption process in agreement with the proposal of Davy and Somorjai.(1) The non-Arrhenius behavior of the rate of condensation, kc, manifests itself in a discontinuity in the range 170-190 K depending on the type of ice and is consistent with the precursor model. The average of the energy of sublimation DeltaH(S) degrees is (12.0 +/- 1.4) kcal/mol for C, B, S, and SC ice and is identical within experimental uncertainty between 136 and 210 K. The same is true for the entropy of sublimation DeltaS(S). In contrast, both gamma and the evaporative flux J(ev) are significantly different for different ices. In the range 130-210 K, J(ev) of H2O ice was significantly smaller than the maximum theoretically allowed value. This corroborates gamma values significantly smaller than unity in that T range. On the basis of the present kinetic parameters, the time to complete evaporation of a small ice particle of radius 1 mum is approximately a factor of 5 larger than that previously thought.

Journal Article↗
PubMed2006

Enhanced protonation of cresol red in acidic aqueous solutions caused by freezing.

The protonation degree of cresol red (CR) in frozen aqueous solutions at 253 or 77 K, containing various acids (HF, HCl, HNO3, H2SO4, and p-toluenesulfonic acid), sodium hydroxide, NaCl, or NH4Cl, was examined using UV/Vis absorption spectroscopy. CR, a weak organic diacid, has been selected as a model system to study the acid-base interactions at the grain boundaries of ice. The multivariate curve resolution alternating least-squares method was used to determine the number and abundances of chemical species responsible for the overlaying absorption visible spectra measured. The results showed that the extent of CR protonation, enhanced in the solid state by 2-4 orders of magnitude in contrast to the liquid solution, is principally connected to an increase in the local concentration of acids. It was found that this enhancement was not very sensitive to either the freezing rate or the type of acid used and that CR apparently established an acid-base equilibrium prior to solidification. In addition, the presence of inorganic salts, such as NaCl or NH4Cl, is reported to cause a more efficient deprotonation of CR in the former case and an enhanced protonation in the latter case, being well explained by the theory of Bronshteyn and Chernov. CR thus served as an acid-base indicator at the grain boundaries of ice samples. Structural changes in the CR molecule induced by lowering the temperature and a presence of the constraining ice environment were studied by the absorption and 1H NMR spectroscopies. Cryospheric and atmospheric implications concerning the influence of acids and bases on composition and reactivity of ice or snow contaminants were examined.

Journal Article↗
PubMed2006

Screening of C60 crystallization using a microfluidic system.

We have carried out screening of C60 crystallization using a simple liquid/liquid interfacial precipitation method in a microfluidic device. By controlling the time, temperature, and concentration, various metastable phases of C60 crystals were found, including tubes, spheres, open-ended hollow columns, stars, branches, and trees. The obtained C60 crystal shapes are similar to those of snow crystals. These findings suggest an urgent need to screen C60 crystallization for the development of fullerene C60 drugs.

Crystallization↗
PubMedDate not supplied

Modeling the hydroclimatic disturbance of soil landscapes in the southern Canadian plains: the problems of scale and place.

The sensitivity of soil landscapes to climatic variability and hydroclimatic events can be expressed as a landscape change safety factor, the ratio of potential disturbance to resistance to change. The use of a geographic information system (GIS) enables the spatially-explicit modeling of landscape sensitivity, but also raises the risk of violating the characteristic scales of disturbance and resistance, because the GIS technically simplifies the extrapolation of models, and associated concepts, to landscapes and scales not represented by the digital data base. Embedding landscape sensitivity into hierarchy theory, the formal analysis of the hierarchical structure of complex systems, provides a conceptual framework for the transfer of models and variables among landscape scales. In the subhumid southern Canadian plains, major hydroclimatic events (strong winds, intense rain, rapid snow melt) cause much of the physical disturbance of soil landscapes and terrestrial ecosystems. Prolonged dry or wet weather influences the resistance of soil and vegetation to these events. The potential disturbance of soil landscapes therefore can be derived from the probabilities of extreme events and seasonal conditions, as recorded in instrumental and proxy climate records. This time series analysis can be linked to the modeling of landscape sensitivity by establishing the probabilities of hydroclimatic events and climatic conditions which may exceed or lower the resistance of individual soil landscapes.

Canada↗
PubMed2001

Attraction of a leaf beetle (Oreina cacaliae) to damaged host plants.

Early in spring, just after the snow melts, the leaf beetle Oreina cacaliae feeds on flowers of Petasites paradoxus. Later in spring they switch to their principle host plant Adenostyles alliariae. The attractiveness of short- and long-term damaged host plants was studied in a wind tunnel. The spring host P. paradoxus was more attractive to the beetles after it had been damaged overnight by conspecifics or artificially, but not when the plants were damaged half an hour before the wind-tunnel experiments. Contrary to P. paradoxus, the principle host plant, A. alliariae was more attractive shortly after an attack by conspecifics (half an hour before the experiment) compared to a undamaged plant, but lost its increased attractiveness when damaged overnight. The enhanced attraction of damaged plants was longer lasting in the spring host P. paradoxus than in the main host A. alliariae. Volatiles emitted by host plants were collected and gas chromatographic analyses of the odors collected showed qualitative and quantitative differences between damaged and undamaged plants. Among the volatiles recorded, green leaf volatiles and mono- and sesquiterpenes dominated. In overnight damaged P. paradoxus plants with an enhanced attractiveness, limonene was emitted in higher amounts. In freshly damaged A. alliariae leaves, more alpha-humulene and germacrene D were emitted compared to (E,E)-alpha-farnesene, whereas in the less attractive A. alliariae plants, more (E,E)-alpha-farnesene was emitted compared to alpha-humulene and germacrene D. In the field, the long lasting attraction of flowering P. paradoxus early in the season may facilitate mating in O. cacaliae after a successful overwintering.

Animals↗
PubMed2001

Identification and survival of the causal organism of leaf smut disease of cowpea in Nigeria.

Protomycopsis phaseoli (Ramak and Subram) is the causal agent of the cowpea leaf smut disease in Nigeria and not Entyloma vignae as claimed by some authors. This pathogen formed dark ash-grey to sooty-black lesions of 3-10 mm in diameter, while young lesions had yellow haloes. P. phaseoli produced dark reddish-brown chlamydospores that are globose to oval measured 23.8 microm, thick-walled and rugose. The chlamydospores germinated and produced globose vesicles. The pathogen grew on potato dextrose agar only when the leaf tissue was dipped in acidified water (1% H2SO4). The organism was slowly growing at 24-28 degrees C with snow white colour. Chlamydospores of P. phaseoli in infected cowpea leaves survived longer when buried in the soil for five months than when they were left on the soil surface for the same period at temperatures (26-27 degrees C) and humidity (70-82%) prevailing in Ibadan. Destruction of leaf debris before crop emergence, long period of rotation and no tillage cropping are suggested to prevent the onset and spread of leaf smut disease of cowpea.

Ascomycota↗
PubMed1997

Purification and characterization of a new mannose-specific lectin from Sternbergia lutea bulbs.

A new mannose-binding lectin was isolated from Sternbergia lutea bulbs by affinity chromatography on an alpha(1-2)mannobiose-Synsorb column and purified further by gel filtration. This lectin (S. lutea agglutinin; SLA) appeared homogeneous by native-gel electrophoresis at pH 4.3, gel filtration chromatography on a Sephadex G-75 column, and SDS-polyacrylamide gel electrophoresis, These data indicate that SLA is a dimeric protein (20 kDa) composed of two identical subunits of 10 kDa which are linked by non-covalent interactions. The carbohydrate binding specificity of the lectin was investigated by quantitative precipitation and hapten inhibition assays. It is an alpha-D-mannose-specific lectin that interacts to form precipitates with various alpha-mannans, galactomannan and asialo-thyroglobulin, but not with alpha-glucans and thyroglobulin. Of the monosaccharides tested only D-mannose was a hapten inhibitor of the SLA-asialothyroglobulin precipitation system, whereas D-glucose, D-galactose and L-arabinose were not. The lectin appears to be highly specific for terminal alpha(1-3)-mannooligosaccharides. The primary structure of SLA appears to be quite similar to that of the snow drop (Galanthus nivalis) bulb lectin which is a mannose-binding lectin from the same plant family Amaryllidaceae. The N-terminal 46 amino acid sequence SLA showed 76% homology with that of GNA.

Amino Acid Sequence↗
PubMed2003

Molecular epidemiology of Norwalk-like virus (NLV) outbreaks occurring in Kyushu Japan between 1988 and 1993.

In nine outbreaks that occurred in the Kyushu district between 1988 and 1993, we determined the nucleotide sequences of Norwalk-like virus (NLV) gene fragments amplified by RT-PCR and molecular-epidemiologically analyzed the NLV epidemics. It is known that the NLV strains isolated from nine outbreaks of acute gastroenteritis, were divided into five clusters consisting of two genogroups. Described by the year of outbreaks, the genogroup-1 (Norwalk-like virus group) was prevalent in 1988, 1989, and 1992, the genogroup-2 (snow mountain-like virus group) was detected in 1988, 1989, and 1993. Especially it was revealed that various strains of NLV were prevalent in the Kyushu district from 1988 to 1989. Epidemics of the Norwalk-like strain continued to be prevalent in 1992 (FP/7/92), and the strains very close to OSAP 18 continued to be prevalent in 1993 (FP/8/93, FP/9/93). Although the strains belonging to Norwalk virus (KY89) in the genogroup-1 and belonging to P1B (OSAP 18) in the genogroup-2 were detected for a prolonged period from 1988 to 1992/ 1993, the homology in these strains was very close, and this study shows that a high homogeneity was conserved in these strains. It was revealed that various strains of NLV were prevalent in the Kyushu district from 1988 to 1989.

Base Sequence↗
PubMed2004

Gold concentrations in abiotic materials, plants, and animals: a synoptic review.

Gold (Au) is ubiquitous in the environment and mined commercially at numerous locations worldwide. It is also an allergen that induces dermatitis in sensitive individuals. Gold concentrations were comparatively elevated in samples collected near gold mining and processing facilities, although no data were found for birds and non-human mammals. Maximum gold concentrations reported in abiotic materials were 0.001 microg L(-1) in rainwater; 0.0015 microg L(-1) in seawater near hydrothermal vents vs. < 0.00004-0.0007 microg L(-1) elsewhere; 5.0 microg kg(-1) dry weight (DW) in the Earth's crust; 19.0 microg L(-1) in a freshwater stream near a gold mining site; 440 microg kg(-1) DW in atmospheric dust near a high traffic road; 843 microg kg(-1) DW in alluvial soil near a Nevada gold mine vs. < 29 microg kg(-1) DW premining; 2.53 mg kg(-1) DW in snow near a Russian smelter vs. < 0.35 mg kg(-1) DW at a reference site; 4.5 mg kg(-1) DW in sewage sludge; 28.7 mg kg(-1) DW in polymetallic sulfides from the ocean floor; and 256.0 mg kg(-1) DW in freshwater sediments near a gold mine tailings pile vs. < 5 microg kg(-1) DW prior to mining. In plants, elevated concentrations of 19 microg Au kg(-1) DW were reported in terrestrial vegetation near gold mining operations vs. < 4 microg kg(-1) DW at a reference site; 37 microg kg(-1) DW in aquatic bryophytes downstream from a gold mine; 150 microg Au kg(-1) DW in leaves of beans grown in soil containing 170 microg kg(-1) DW; up to 1.06 mg kg(-1) DW in algal mats of rivers receiving gold mine wastes; and 0.1-100 mg kg(-1) DW in selected gold accumulator plants. Fish and aquatic invertebrates contained 0.1-38.0 microg Au kg(-1) DW. In humans, gold concentrations up to 1.1 microg L(-1) were documented in urine of dental technicians vs. 0.002-0.85 microg L(-1) in reference populations; 2.1 microg L(-1) in breast milk, attributed to gold dental fillings and jewelry of mothers; 1.4 mg kg(-1) DW in hair of goldsmiths vs. a normal range of 6-880 microg kg(-1) DW; 2.39 mg L(-1) in whole blood of rheumatoid arthritis patients receiving gold thiol drugs to reduce inflammation (chrysotherapy) vs. a normal range of 0.2-2.0 microg L(-1); and 60.0 to 233.0 mg kg(-1) fresh weight (FW) in kidneys of rheumatoid arthritis patients undergoing active chrysotherapy vs. < 42.0 mg kg(-1) FW kidney 140 months posttreatment.

Animals↗
PubMed1999

[Enjoying the sun well protected].

According to the annual figures, skin cancer is the fastest growing type of cancer: one child in every hundred is currently at risk of developing a melanoma, the most malignant form of skin cancer. Surveys show that people are changing their behaviour when it comes to dealing with the sun. But only in small steps. That's why the Cancer League launches a sun protection campaign every year. Simple rules for protection from the sun: Between 11.00 a.m. and 3.00 p.m. (summer time), people should remain in the shade. A head covering and light, loose clothing should be worn in the sun. Tightly-woven, strong-coloured fabric offers better UV protection than coarsely-woven natural fibres. Sunglasses protect the eyes. The choice of sun screen depends on the skin type, the desired level of protection and the intended activity in the sun. The sun cream should be applied liberally half an hour before exposure to the sun. Depending on the particular preparation, it may need to be reapplied after bathing or showering to ensure that sun protection is maintained. Where reflective surfaces are present, e.g. sand, snow, cement and water, it is advisable to use sun protection creams even in the shade. Babies up to one year of age should be kept in the shade and sun protection agents should not be used on them. Like other chemical products, these may irritate the sensitive skin of babies and trigger allergies. Sunscreens used in older children should be waterproof, contain no alcohol and possess a high sun protection factor (at least SPF 15). Baby oil should not be used since it makes the child's skin even more sensitive to light. Parents should set an example to children in the way they protect themselves from the sun. Artificial UV light from sunbeds should be avoided, particularly by children and persons with an increased risk of developing a melanoma.

Adult↗
PubMed1995

Galileo multispectral imaging of Earth.

Nearly 6000 multispectral images of Earth were acquired by the Galileo spacecraft during its two flybys. The Galileo images offer a unique perspective on our home planet through the spectral capability made possible by four narrowband near-infrared filters, intended for observations of methane in Jupiter's atmosphere, which are not incorporated in any of the currently operating Earth orbital remote sensing systems. Spectral variations due to mineralogy, vegetative cover, and condensed water are effectively mapped by the visible and near-infrared multispectral imagery, showing a wide variety of biological, meteorological, and geological phenomena. Global tectonic and volcanic processes are clearly illustrated by these images, providing a useful basis for comparative planetary geology. Differences between plant species are detected through the narrowband IR filters on Galileo, allowing regional measurements of variation in the "red edge" of chlorophyll and the depth of the 1-micrometer water band, which is diagnostic of leaf moisture content. Although evidence of life is widespread in the Galileo data set, only a single image (at approximately 2 km/pixel) shows geometrization plausibly attributable to our technical civilization. Water vapor can be uniquely imaged in the Galileo 0.73-micrometer band, permitting spectral discrimination of moist and dry clouds with otherwise similar albedo. Surface snow and ice can be readily distinguished from cloud cover by narrowband imaging within the sensitivity range of Galileo's silicon CCD camera. Ice grain size variations can be mapped using the weak H2O absorption at 1 micrometer, a technique which may find important applications in the exploration of the moons of Jupiter. The Galileo images have the potential to make unique contributions to Earth science in the areas of geological, meteorological and biological remote sensing, due to the inclusion of previously untried narrowband IR filters. The vast scale and near global coverage of the Galileo data set complements the higher-resolution data from Earth orbiting systems and may provide a valuable reference point for future studies of global change.

Africa↗
PubMed2001

How phenology influences physiology in deciduous forest spring ephemerals.

Spring ephemerals of deciduous forest are adapted to take advantage of the high-light period available in early spring. They appear shortly after snow melt and complete their aboveground growth, including fruit production, within 2 months. After they produce new buds, they senesce and enter dormancy. Dormancy is not very deep in spring ephemerals and during summer differentiation occurs in the bud of the apparently resting organ. Low soil temperatures release dormancy, and the shoots and roots then grow slowly over autumn and winter. The goal of this paper is to show how this characteristic phenology influences many aspects of spring ephemerals' physiology, and the influences these different physiological parameters have on each other. Spring ephemerals have high photosynthetic rates that allow them to rapidly accumulate carbohydrates and complete their aboveground growth in a few weeks. To sustain high photosynthetic rates in early spring, the plants must be able to absorb water efficiently at low soil temperatures and to allocate large amounts of nutrients to the shoot to compensate for lower enzymatic activity at low temperatures. Nutrients are mainly absorbed in spring, although the root system is established in autumn. This means that a large amount of both carbohydrates and nutrients is translocated from the perennial organ to the developing shoot starting in autumn through early spring. Spring ephemerals have low nutrient absorption rates, but high resorption efficiency during leaf senescence. Nevertheless, their high nutrient needs restrict them to rich forest soils. The annual growth rate of spring ephemerals is very slow and this is more likely related to the inherent slow growth rate of the perennial organ than to their short leaf life. As soon as carbohydrate reserves are replenished in spring, sink limitation apparently builds up and induces leaf senescence. A better understanding of the factors controlling the growth rate of spring ephemerals is needed before we can predict these plants' response to climatic changes.

Journal Article↗
PubMed2002

Ecophysiology of Antarctic vascular plants.

Most of the ice and snow-free land in the Antarctic summer is found along the Antarctic Peninsula and adjacent islands and coastal areas of the continent. This is the area where most of the Antarctic vegetation is found. Mean air temperature tends to be above zero during the summer in parts of the Maritime Antarctic. The most commonly found photosynthetic organisms in the Maritime Antarctic and continental edge are lichens (around 380 species) and bryophytes (130 species). Only two vascular plants, Deschampsia antarctica Desv. and Colobanthus quitensis (Kunth) Bartl., have been able to colonize some of the coastal areas. This low species diversity, compared with the Arctic, may be due to permanent low temperature and isolation from continental sources of propagules. The existence of these plants in such a permanent harsh environment makes them of particular interest for the study of adaptations to cold environments and mechanisms of cold resistance in plants. Among these adaptations are high freezing resistance, high resistance to light stress and high photosynthetic capacity at low temperature. In this paper, the ecophysiology of the two vascular plants is reviewed, including habitat characteristics, photosynthetic properties, cold resistance, and biochemical adaptations to cold.

Journal Article↗
PubMed2002

Exfoliation syndrome: frequency, gender distribution and association with climatically induced alterations of the cornea and conjunctiva.

PURPOSE: To investigate exfoliation syndrome (ES) in order to elucidate gender distribution and the roles of genetic and climatic factors in its manifestation. MATERIAL AND METHODS: We studied the gender distribution of ES and the association between ES and the appearance of certain climatically induced disorders (pterygium, climatic droplet keratopathy) and the size of pingueculae in populations living in the Arctic region, in temperate regions and in tropical regions. This involved a total of 11 samples taken in eight different countries, comprising 2206 persons of both genders over the age of 50 years. RESULTS: A total of 1051 males were investigated for ES and 147 of them (14.0%) were found to have it. The corresponding figures for females were 1093 and 177 (16.2%). After standardization according to age, no systematic difference between the genders was found in the study. The frequency of ES varied greatly. It was not observed at all in the Inuit (Eskimos) but was found most frequently (about 30%) among the Saami (Lapps), Aland Islanders, Finns, Icelanders and Russians over 70 years of age. After the age of 50, the frequency of ES increases rapidly with age in all populations. However, the curves for ES in people living in the tropics show a delay of about 10 years. In contrast, the frequency of climatically caused changes (pterygium, climatic keratopathy and pronounced pinguecula) mostly peaks at the age of 50 years and is highest in the tropics and in the Arctic. Males in these regions tended to be more affected by climatically caused changes than females. Likewise, in tropical climates, where radiation from the sun is strong, and in Lapland and Novosibirsk, where there is radiation from snow, males showed more evidence of ES than females. However, examination of 506 patients from a private practice in South Finland, who were under observation for glaucoma or for risk of glaucoma, showed females to be in the majority of those with ES. CONCLUSIONS: As a rule, climate does not appear to influence the occurrence of ES. However, in tropical countries, where radiation from the sun is strong, ES was more common among males than among females. In the light of its peculiar population distribution, even when climatic factors are considered, there would appear to be an important genetic factor involved in the manifestation of ES.

Age Distribution↗
PubMed2002

Objects relating to the Danish Ophthalmological Society at the Medical History Museum.

Some of the objects from the Medical History Museum, University of Copenhagen, concerned with the century-old Danish Ophthalmological Society are mentioned, together with some objects concerned with our predecessors. Jannik Bjerrum's campimeter at 1-2 m-distance reveals glaucomatous arcuate scotoma. [figure: see text] Marius Tscherning's many scientific papers and his ophthalmophacometer (also measuring accommodation), abberoscope, adaptoscope, colour vision, punctual meniscen spectacle glasses etc. are housed in the Museum. K.K.K. Lundsgaard's spectacle collection and cataract paper, Gordon Norrie's colour vision lantern and his personal pince-nez are described. Gustav Østerberg's contact lens practice and his pictorial visual chart, Jørn Boberg-Ans' pioneer artificial lens surgery dating from 1958, are all examples of the work of members of the Society. From our predecessors, we refer to the first cataract extraction in Denmark in 1670 (F. Borri on a goose); Georg Heuermann's on humans dating from 1755 and the reintroduction of the operation in 1810 by C.C. Withusen, V. Krenchel's (1844-1885) ophthalmoscope with a movable mirror and his colour vision lantern; A. Stadfeldt's instruments for examination of the refractive index of the human lens, MD thesis dating from 1898. In addition, snow goggles from Greenland and eye-baths are described.

Denmark↗
PubMed2002

Mucocutaneous pigmented macule as a result of zinc deposition.

BACKGROUND: Mucocutaneous depositions of various metals such as silver, lead, gold, arsenic, mercury, iron, and bismuth have been previously published. Heavy metal deposition typically occurs in the setting of either prolonged topical application to intact skin, topical application to eroded or ulcerated skin, as a result of either parenteral administration, or due to penetrating traumatic exposure. METHOD: We report a unique case of mucocutaneous pigmentation occurring in a snow skier after topical application of a zinc-containing sunblock. Formalin-fixed paraffin-embedded tissue was utilized for electron microscopy. RESULT: Backscatter electron imaging and energy dispersive spectroscopy revealed that the dominant metal present was zinc. CONCLUSIONS: Mucocutaneous deposition of metals is enhanced by damage to the surface epithelium. Metal-containing topical agents, although commonly used, may rarely result in a permanent pigmentary alteration. We believe similar cases of mucocutaneous deposition of zinc exist; however, as these may be currently misdiagnosed as amalgam tattoos, the true incidence of this disorder is presently undefined.

Adult↗