Altered expression of dermokine in skin disorders

BACKGROUND

Although dermokine-β, a glycoprotein expressed in epithelial cells, does not have significant homology to other proteins, its carboxyl-terminal domain shares a high pI value with many cytokines, suggesting similar functions.

OBJECTIVE

To better understand the biology of dermokine, we here determined its localization under pathological conditions and examined factors that regulate its expression.

METHODS

We generated an anti-human dermokine-β/γ monoclonal antibody cross-reacting with the mouse protein. Using this antibody, immunohistological staining and Western blotting of dermokine-β/γ were performed with various tissue samples.

RESULTS

Although human dermokine-β/γ was expressed in almost all granular layers, upper spinous layers of the skin were also stained with anti-dermokine-β/γ antibody in inflammatory skin disorders. Dermokine-β/γ was expressed in keratoacanthoma and a part of well-differentiated squamous cell carcinoma (SCC). However, dermokine-β/γ was not detected in poorly differentiated SCC or tumours derived from non-keratinocytes. In mice, dermokine-β/γ-expressed keratinocytes were increased in models of contact hypersensitivity, ultraviolet-irradiated skin injury and wound healing. Consistent with expanded distribution in inflammatory skin diseases, proinflammatory cytokines such as interleukin-1β, interleukin-12, and tumour necrosis factor-α augmented dermokine-β/γ expression in cultured human keratinocytes. In contrast, growth factors including epidermal growth factor, insulin-like growth factor-I, keratinocyte growth factor and transforming growth factor-α significantly reduced dermokine expression.

CONCLUSION

These results provide novel insights into the physiological and pathological significance of dermokine in the epidermis.

Physicochemical characterization and structural evaluation of a specific 2:1 cocrystal of naproxen-nicotinamide

Physicochemical characterization and structural evaluation of a 2:1 naproxen-nicotinamide cocrystal were performed. The 2:1 cocrystal showed rapid naproxen dissolution and less water vapor adsorption, indicating better pharmaceutical properties of naproxen. The unique 2:1 cocrystal formation was evaluated by solid-state nuclear magnetic resonance (NMR). The assignments of all H and (13) C peaks for naproxen and the cocrystal were performed using dipolar-insensitive nuclei enhanced by polarization transfer and (1) H-(13) C cross-polarization (CP)-heteronuclear correlation (HETCOR) NMR measurements. The (13) C chemical shift revealed that two naproxen molecules and one nicotinamide molecule existed in the asymmetric unit of the cocrystal. The (1) H chemical shifts indicated that the carboxylic group of the naproxen in the cocrystal was nonionized, and the CH-π interaction between naproxens was very strong. From the (1) H-(13) C CP-HETCOR NMR spectrum with contact time of 5 ms, two different synthons, carboxylic acid-amide and carboxylic acid-pyridine ring, were found between naproxen and nicotinamide. Single-crystal X-ray analysis, which supported the solid-state NMR results, clarified the geometry and intermolecular interactions in more detail. The structure is unique among pharmaceutical cocrystals because each carboxyl group of the two naproxens formed different intermolecular synthons.

Formation mechanism of a new carbamazepine/malonic acid cocrystal polymorph

A new 2/1 carbamazepine (CBZ)/malonic acid (MA) cocrystal polymorph form C was formed using a vibrational rod mill, whereas the known cocrystal polymorph form A was prepared using a ball mill. IR measurements showed that the interaction between CBZ and MA in cocrystal form C was formed by amide-carboxylic acid heterosynthons, similar to that in cocrystal form A. However, NMR results showed that the molecular states of CBZ at the dibenzazepine ring appeared to be different, which could be due to variation in either the conjugation of the aromatic rings or the π-π interaction of CBZ. Factors affecting the formation of cocrystal polymorphs, such as heat and force, were investigated to clarify the formation mechanism.

Molecular states of p-dimethylaminobenzonitrile coground with β-cyclodextrin investigated using solid-state fluorescence spectroscopy

Changes in molecular states of p-dimethylaminobenzonitrile (DMABN) coground with β-cyclodextrin (β-CD) were examined using solid-state fluorescence measurements. Formation of a DMABN/β-CD inclusion complex by coprecipitation was confirmed by powder X-ray diffraction measurement. The powder X-ray diffraction pattern of the ground mixture was a halo pattern and differed from the pattern of the mixture prepared by coprecipitation. Solid-state fluorescence measurements revealed emission by DMABN crystals in a twisted intermolecular charge-transfer state at 473 nm. DMABN in the DMABN/β-CD coprecipitate had a fluorescence emission peak at 393 nm due to its planar structure. In contrast, DMABN in a DMABN/β-CD ground mixture had an emission peak at 473 nm due to its twisted structure. Grinding time-dependent structural changes in DMABN were evaluated using fluorescence lifetime and relative quantum yield measurements. Structural changes in DMABN in the DMABN/β-CD coprecipitate from a planar to a twisted structure were observed with grinding. DMABN, dispersed in microcrystalline cellulose (CC) molecules in a DMABN/CC ground mixture, had a fluorescence emission peak at 473 nm. However, the excitation spectrum of a DMABN/β-CD ground mixture differed from that of DMABN in CC. These results indicated that the molecular state of DMABN accommodated in the β-CD cavity differs between the coprecipitate and the ground mixture.

Instability of Superplastic Aluminium Alloys

The influence of the strain hardening coefficient,γ,and the strain rate sensitivity exponent, m, on the onset and growth of necking has been pointed out in many models about plastic instability controlled by the mechanical properties of materials. In this paper, the instability parameter I (=(l-γ-m)/m) proposed by Hart is used to relate the values of m (=∂lnσ/∂lnέ) and γ (=∂σ/(σ·∂ε)) for some superplastic aluminium alloys. These values of m and γ were calculated from the load-elongation curve at various strain-rates in constant strain-rate tests with periodic m determinations by strain-rate departures of small magnitude. It will be shown that the strain hardening due to grain growth contributes to an increase in the stability of plastic deformation during superplastic flow. However the decrease of m due to dynamic grain growth with strain causes superplastic deformation to be unstable near the onset of fracture. The transition of I values from negative to positive coincides with a decrease in m value and flow stress.

It is concluded that the development of necks can be characterized by an instability parameter I which include the effect of strain hardening caused by strain induced grain growth.

Superplasticity in P/M Aluminium Alloys

Recent advances in the technologies of powder metallurgy lead to the development of some superplastic aluminium alloys containing a deliberate addition of a large amount of Zr and /or Cr and Mn that exhibit the high strain rates superplasticity. For a few alloy systems, the large elongation more than 500% has been observed over the strain rates of 1×10−1s−1, which rates are two or three orders of magnitude faster than those at which superplasticity is found in conventional superplastic aluminium alloys produced by ingot metallurgy. The high strain-rates superplasticity obtained in both type of fully static recrystallized and dynamic recrystallized P/M aluminium alloys. The decreasing of initial size of grains and/or sub-grains leads to the increasing the strain-rates for superplastic flow in both types of alloys. The refinement of grains or sub-grains size is one of necessary and important to obtain the high strain-rates superplasticity.