| 1. |
- Stierner, Ulrika, 1952, et al.
(författare)
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Urinary excretion of 5-S-cysteinyldopa in relation to skin type, UVB-induced erythema, and melanocyte proliferation in human skin.
- 1988
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Ingår i: The Journal of investigative dermatology. - 0022-202X. ; 91:5, s. 506-10
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Tidskriftsartikel (refereegranskat)abstract
- 5-S-Cysteinyldopa (5-S-CD) is found in all pigment-producing cells and is the major precursor of phaeomelanin. However, the melanocyte specificity of the compound has been questioned. In order to elucidate the origin of 5-S-CD, we have now systematically studied the relationship between the 5-S-CD excretion in urine and the size of the melanocyte organ, UV-induced melanocyte proliferation, skin type, and the erythemal reaction. The skin type had no influence on the basal excretion of 5-S-CD. There was no significant correlation between the basal 5-S-CD excretion and the size of the melanocyte organ; that is, the number of skin melanocytes and nevi. During the irradiation, subjects with skin type II developed a more pronounced erythema (p less than 0.01) and had a significantly higher 5-S-CD excretion than those with skin type III-IV (p less than 0.01). No correlation was found between 5-S-CD excretion and UV-induced melanocyte proliferation. The lack of correlation between the basal 5-S-CD excretion and skin type or number of melanocytes suggests that the basal 5-S-CD in urine is mainly of extra-melanocytic origin. Our findings favor the view that the increase in 5-S-CD excretion during UV irradiation is due to UV damage.
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| 2. |
- Stierner, Ulrika, 1952, et al.
(författare)
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UVB irradiation induces melanocyte increase in both exposed and shielded human skin.
- 1989
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Ingår i: The Journal of investigative dermatology. - 0022-202X. ; 92:4, s. 561-4
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Tidskriftsartikel (refereegranskat)abstract
- This study demonstrates for the first time in humans that UV light induces an increase of the melanocyte population in exposed skin as well as in shielded areas. Because an increased mitotic activity could promote tumor development, UV exposure might play a role in melanoma development not only in exposed but also in covered skin. In addition, it was found that subjects who initially had a small melanocyte population showed a larger increase in both exposed and covered skin compared to those with a high initial density. Individuals with a low density might therefore constitute a risk group for the development of malignant melanoma. These findings support the view that infrequent periods of intensive UV irradiation might be more harmful than regular exposure.
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| 3. |
- Andersson, Per, et al.
(författare)
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Effect of guest molecule size on the thermal conductivity and heat capacity of clathrate hydrates
- 1983
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Ingår i: Journal of Physics C: Solid State Physics. - : Institute of Physics Publishing (IOPP). - 0022-3719. ; 16:8, s. 1423-1432
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Tidskriftsartikel (refereegranskat)abstract
- Using the transient hot-wire method, we have measured both the thermal conductivity, lambda, and the heat capacity per unit volume, rho cp, for structure II clathrate hydrates of 1,3-dioxolane (DO) and cyclobutanone (CB), and compared the results with similar previous measurements for tetrahydrofuran (THF). All three clathrate hydrates showed a glass-like temperature dependence of lambda. The magnitude of lambda was small, about the same as liquid water, and decreased in the sequence DO-THF-CB which corresponds to an increase in the size of the guest molecule. There was some evidence to support the suggestion that the dominant process in the thermal resistivity was associated with excitation of rotational vibrations of the guest molecules. In all cases, the pressure dependence of lambda was unusually small. We found evidence that there was a phase transition on the CB clathrate hydrate (and almost certainly also in the DO clathrate) at 135K and 1 GPa, which are essentially the same conditions under which we previously found an analogous transition for THF. In each case, the resultant presumably metastable phase may be a new type of clathrate hydrate arising from densification of the host structure. For the three clathrates, our results for rho cp did not depend on the nature of the guest species, and at 0.1 GPa, were the same as previously found for ice Ih.
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| 4. |
- Andersson, Per, et al.
(författare)
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The phase diagram of ammonium iodide (NH4I) under pressure, and a comparison with NH4Cl and NH4Br
- 1987
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Ingår i: Journal of Physics C: Solid State Physics. - : Institute of Physics (IOP). - 0022-3719. ; 20:29, s. 4737-4743
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Tidskriftsartikel (refereegranskat)abstract
- During recent measurements of thermal conductivity using the transient hot-wire method, data were obtained for pressure-temperature coordinates corresponding to transitions amongst phases I, II, III and IV of NH4I which extended reliable knowledge of the phase diagram to pressures of 2 GPa. Comparison of the phase diagrams of NH4Cl, NH4Br and NH4I showed that a generalised phase diagram covering these substances was a poor approximation if the higher-order critical points or triple points (as appropriate) were made coincident. However, the ferro-ordered-to-disordered phase transition boundaries of these substances could be made to follow a common curve with an alternative empirical adjustment of pressure and temperature. When this was done, the adjustments of temperature required were correlated with differences in barrier height opposing re-orientational motion of the ammonium species.
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| 5. |
- Andersson, Per
(författare)
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Thermal conductivity under pressure and through phase transitions in solid alkali halides : I. Experimental results for KCl, KBr, KI, RbCl, RbBr and RbI
- 1985
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Ingår i: Journal of Physics C: Solid State Physics. - : Institute of Physics (IOP). - 0022-3719. ; 18:20, s. 3943-3955
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Tidskriftsartikel (refereegranskat)abstract
- The thermal conductivity, lambda , of polycrystalline KCl, KBr, KI, RbCl, RbBr and RbI has been measured at temperatures (T) from 100-400K at pressures (P) up to about 2.6 GPa, using the transient hot-wire method. Extensive results were obtained for lambda (T,P) of both the low-pressure (NaCl-type) and high-pressure (CsCl-type) phases. There was generally good agreement with previous results for lambda (P) at room temperature, the decrease of lambda through the phase transition and lambda (T) at atmospheric pressure. The heat capacity per unit volume was also measured simultaneously but for technical reasons data could be obtained only near room temperature. Corresponding values of specific heat capacity were in good agreement with previous work over the whole pressure range.
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| 6. |
- Andersson, Per, et al.
(författare)
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Thermal resistivity of ice Ih near the melting point
- 1980
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Ingår i: Journal of Physics C: Solid State Physics. - : Institute of Physics Publishing (IOPP). - 0022-3719 .- 1747-3802. ; 13:4, s. L73-L76
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Tidskriftsartikel (refereegranskat)abstract
- The thermal resistivity r(T) of ice Ih has been re-measured from 120K to as close as practicable to melting. Measurements were made under isobaric conditions at a pressure of 0.07 GPa, and corrected to isochoric conditions. The resultant deviation from the simple theoretical prediction, r/T=constant, has been plausibly accounted for by interaction between optic and acoustic phonons. Thermal resistivity arising from the presence of point defects has been shown to be of negligible importance.
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| 7. |
- Andersson, Staffan, et al.
(författare)
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The thermal conductivity and heat capacity of single-crystal Si under hydrostatic pressure
- 1988
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Ingår i: Journal of Physics C: Solid State Physics. - : Institute of Physics Publishing (IOPP). - 0022-3719. ; 21:20, s. 3727-3735
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Tidskriftsartikel (refereegranskat)abstract
- The thermal conductivity λ and heat capacity ρcP per unit volume of single-crystal Si have been measured under hydrostatic pressure up to 1 GPa at room temperature. The thermal conductivity was found to increase slightly with increasing pressure. For the volume dependence of λ expressed in terms of the Bridgman parameter g=-( δ(ln λ )/ δ(ln V))T, the authors obtained g=0.4. The specific heat capacity cP, calculated from their measured ρcP, was found to be constant against pressure.
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| 8. |
- Andersson, Staffan, et al.
(författare)
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Thermal conductivity and heat capacity of single-crystal LiF and CaF2 under hydrostatic pressure
- 1987
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Ingår i: Journal of Physics C: Solid State Physics. - : Institute of Physics Publishing (IOPP). - 0022-3719. ; 20:35, s. 5951-5962
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Tidskriftsartikel (refereegranskat)abstract
- The thermal conductivity, lambda , and heat capacity per unit volume, rho cp, have been measured under hydrostatic pressure up to 1 GPa at room temperature, using a dynamic two-strip method. The standard deviation of lambda and rho cp was always better than 0.2%. The volume dependence of lambda expressed in terms of the Bridgman parameter, -( delta ln (lambda) / delta ln V)T, was found to be 7.9 for LiF and 9.2 for CaF2. The specific heat capacity, cp, calculated from the measured rho cp, was found to decrease slightly with increasing pressure.
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| 9. |
- Ankerst, J., et al.
(författare)
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Microcalorimetry as a tool for the detection of complement-dependent cytotoxicity
- 1985
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Ingår i: Journal of Immunological Methods. - : Elsevier BV. - 0022-1759. ; 77:2, s. 267-274
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Tidskriftsartikel (refereegranskat)abstract
- Microcalorimetry using a 4-channel static ampoule microcalorimeter of thermopile type has been evaluated as a tool for the detection of complement-dependent cytotoxicity against the surface antigens of living cells. Cytotoxic reactions mediated by a rabbit antiserum against human white blood cells and by 2 different monoclonal antibodies recognizing a melanoma-associated antigen on a human melanoma cell line were studied. The cytotoxic reactions were registered as a decrease of the heat production rate when the cells were exposed to antibodies in the presence of active complement as compared to the heat production rate of the cells exposed to the same antibodies in the presence of inactive complement. This investigation shows that microcalorimetry can be used as a highly sensitive method for the detection of complement-dependent immune reactions, detecting antibody dilutions higher than 10-5. It also indicates that microcalorimetry may become a particularly important technique in the analysis of the kinetics of cytotoxic immune reactions in vitro.
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| 10. |
- Ankerst, J., et al.
(författare)
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Use of microcalorimetry in analysing the kinetics of ADCC
- 1986
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Ingår i: Journal of Immunological Methods. - : Elsevier BV. - 0022-1759. ; 88:2, s. 259-264
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Tidskriftsartikel (refereegranskat)abstract
- Microcalorimetry was found to be a useful technique for the demonstration of antibody-dependent cellular cytotoxicity (ADCC) against human melanoma cells mediated by a heterologous rabbit antiserum and two monoclonal antibodies in combination with human peripheral blood lymphocytes as effector cells. The rabbit antiserum and the monoclonal IgG3 antibody 2B2 directed against the GD3 ganglioside expressed cell-inhibitory effects resulting in a decreased heat production rate over 2-18 h of incubation. The 4.2 monoclonal IgM antibody to GD3 had no similar cell-inhibitory effect. In contrast, the 4.2 antibody expressed a much stronger effect than 2B2 in tests for complement-dependent cytotoxicity. The kinetics of these effects were quite reproducible. It is concluded that microcalorimetry is a sensitive and particularly suitable method for the analysis of cytotoxicity kinetics.
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