bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of 1,320 nm Nd:YAG laser for wrinkle reduction and the treatment of atrophic acne scarring in Asians
Authors: Chan Henry H.L. , Lam Lai‐kun , Wong David S.Y. , Kono Taro , Trendell‐Smith Nigel
Published: February 2004

Background and objectives

The role of 1,320 Nd:YAG in non‐ablative skin rejuvenation in Asians is has not been established. Furthermore, no study has investigated the effectiveness of 1,320 Nd:YAG laser in the treatment of atrophic scarring in Asians. The objective of our study was to investigate the effectiveness of 1,320 Nd:YAG laser in wrinkle reduction and the treatment of atrophic acne scarring in Asians.

Study Design/Materials and Methods

Twenty‐seven female patients were included in the study: seven were treated for acne scarring and the others for wrinkle reduction. A 1,320 nm Nd:YAG laser (Cooltouch II, Roseville, CA) was used to treat both the cheeks and forehead for the patients with wrinkles, and both cheeks only for patients with atrophic acne scarring. All patients received treatment in the post‐auricular areas. A spot size of 10 mm was used, and three passes were performed (two pre‐cooling and one post‐cooling). Patients were treated monthly for 6 months. All patients were subjectively assessed before and after their last treatment sessions using a structured questionnaire, and objectively assessed by the use of clinical photographs for by independent observers. A cutometer was used to assess viscoelasticity, and biopsies were taken at the post‐auricular site for assessment by a pathologist.

Results

The overall degree of patients' satisfaction was rated as 4.9 (range 0–9.8) for wrinkle reduction and 4 (range 0–10) for acne scarring. In terms of objective assessment by independent observers, the degree of improvement was considered to be mild or no change in most cases. The independent pathologist who assessed the degree of improvement in terms of increased collagen production detected no change in 8 patients, mild improvement in 9, and moderate improvement in 10.There was also improvement in term of epidermal thickness in 13 cases. Assessment by viscoelasticity indicated a significant degree of improvement in most parameters in both groups of patients. Blistering occurred in five cases, all in the central facial areas, and post‐inflammatory hyperpigmentation occurred in three cases. All cases of PIH resolved after the use of 4% hydroquinoine. There was no scarring or hypopigmentation.

Conclusions

The 1,320 nm Nd:YAG laser is effective for wrinkle reduction and atrophic acne scar improvement, but to further enhance the clinical outcome a combination approach with another device such as IPL and a surgical technique such as subcision is necessary. Lasers Surg. Med. 34:98–103, 2004. © 2004 Wiley‐Liss, Inc.
Port wine stain treatment with a dual‐wavelength Nd:Yag laser and cryogen spray cooling: A pilot study
Authors: Ahčan Uroš , Zorman Peter , Recek Dejan , Ralca Simon , Majaron Boris
Published: February 2004

Background and Objectives

We report on a pilot study of port wine stain (PWS) treatment with a prototype Nd:YAG/KTP laser system, emitting simultaneously at 1,064 and 532 nm, and equipped with a cryogen spray cooling (CSC) device.

Study Design/Patients and Methods

On 10 patients (4–36 years old, mean: 16.2 years) with skin types II‐III, therapeutic efficacy of the dual‐wavelength laser (KTP+) was compared with a standard KTP laser (532 nm only) at the same pulse duration (25 millisecond), spot diameter (3 mm), and CSC parameters. The fluences were selected in order to obtain the same immediate response with both laser systems. Blanching of each test segment was assessed 8 weeks post treatment by an independent evaluator and by the subjects, and graded on a 1–4 scale.

Results

Significant blanching of PWS was noted 8 weeks after a single therapeutic session with the KTP+ laser (mean: 532 nm radiant exposure: 8.2 J/cm2), very similar to that observed with KTP at 12.4 J/cm2. The evaluator noticed a slight brownish coloration in areas treated with the KTP+ laser. Isolated beam‐sized atrophic scars were present in two patients where KTP+ (9 and 10 J/cm2) and KTP (14 J/cm2) lasers were used.

Conclusions

The addition of 1,064 nm radiation allowed a significant reduction of 532 nm radiant exposure with no loss of efficacy in PWS treatment. Lasers Surg. Med. 34:164–167, 2004. © 2004 Wiley‐Liss, Inc.
Treatment of alopecia areata with the 308‐nm xenon chloride excimer laser: Case report of two successful treatments with the excimer laser
Authors: Gundogan Cuneyt , Greve Bärbel , Raulin Christian
Published: February 2004

Background and Objectives

Alopecia areata is a common disease of unknown etiology; it causes significant cosmetic and psycho‐social distress for most of the people it affects. We report on an innovative form of treatment in two patients with typical alopecia areata on the capillitium.

Study Design/Patients and Methods

We successfully treated two patients whose alopecia areata had worsened progressively for 3 and 14 weeks. The treatment involved the use of a 308 nm xenon chloride excimer laser (dosage 300–2,300 mJ/cm2 per session).

Results

After 11 and 12 sessions within a 9‐week and 11‐week period, the entire affected focus showed homogenous and thick regrowth. No relapse was observed during the follow‐up period of 5 and 18 months.

Conclusions

The use of the excimer laser is an effective, elegant, and safe means of treatment and has good tolerability. Analogous to topical treatment of alopecia areata, the immunosuppressive mechanism of the excimer laser can be interpreted as an induction of T‐cell apoptosis. This new means of treatment has yet to be discussed in medical literature. Further studies with greater numbers are needed to assess its potential more precisely and evaluate the excimer laser in treating alopecia areata. Lasers Surg. Med. 34:86–90, 2004. © 2004 Wiley‐Liss, Inc.
Increase of dermal blood volume fraction reduces the threshold for laser‐induced purpura: Implications for port wine stain laser treatment
Authors: Svaasand Lars O. , Aguilar Guillermo , Viator John A. , Randeberg Lise L. , Kimel Sol , Nelson J. Stuart
Published: February 2004

Background and Objectives

The average success rate in achieving total blanching of port wine stain (PWS) lesions treated with laser‐induced selective photothermolysis is below 25%, even after multiple treatments. This is because smaller diameter (5–20 μm) PWS blood vessels are difficult to destroy with selective photothermolysis since the volumetric heat generated by absorption of laser light is insufficient to adequately heat the entire vessel wall. The aim of this study was to investigate a potential technique for more efficient photocoagulation of small diameter PWS blood vessels in PWS that respond poorly to selective photothermolysis.

Study Design/Materials and Methods

The blood volume fraction (BVF) in the upper dermis of the forearm of human volunteers was increased by placing an inflated blood pressure cuff on the upper arm. Applied pressures were in the range of 80–100 mm Hg for up to 5 minutes. The increased BVF was determined by matching reflectance spectra measured with that computed using a diffusion model. The impact of increased BVF on purpura formation induced by a 0.45 milliseconds pulsed dye laser (PDL) at 585 nm wavelength was investigated in normal and in PWS skin.

Results

In the presence of a 100 mm Hg pressure cuff, the BVF, as determined from the diffusion model, increased by a factor of 3 in the forearm and by 6 in the hand. Increasing BVF by a factor of 3 corresponds to an increase in blood vessel diameters by a factor of √3 ≈ 1.7. BVF increased at 1–3 minutes after application of the pressure cuff, remained constant at 3–5 minutes, and returned to baseline values at 3 minutes after removal of the pressure cuff. Approximately 40% less radiant exposure was needed to induce the same amount of purpura after PDL irradiation when the blood pressure cuff was used. Applying an 80 mm Hg pressure cuff reduced the required radiant exposure for purpura formation by 30%. Heating of blood vessels was calculated as a function of vessel diameter and of radiant exposure (at 585 nm and at 0.5 and 1.5 milliseconds pulse duration).

Conclusions

Enlarging the vessel lumen, for example, by obstructing venous return, can significantly reduce the “small‐vessel‐limitation” in PDL treatment of PWS. Dilation of PWS blood vessels enables a more efficient destruction of smaller vessels without increasing the probability of epidermal damage. Lasers Surg. Med. 34:182–188, 2004. © 2004 Wiley‐Liss, Inc.
Effect of skin indentation on heat transfer during cryogen spray cooling
Authors: Basinger Brooke , Aguilar Guillermo , Nelson J. Stuart
Published: February 2004

Background and Objectives

Cryogen spray cooling (CSC) is used to pre‐cool the epidermis during dermatological laser procedures such as treatment of port wine stain (PWS) birthmarks, hair removal, and non‐ablative photorejuvenation. Thus far, heat transfer studies related to CSC optimization have assumed a flat surface but clinical observation suggests that human skin indents due to the force of an impinging cryogen spray.

Study Design/Materials and Methods

High‐speed videos of cryogen spray impingement on in vivo human skin were taken and the resulting indentations characterized as a function of both nozzle‐to‐skin distance and anatomic location. Detectors with pre‐formed indentations were constructed and heat flux measurements were performed at two nozzle‐to‐surface distances.

Results

Indentation causes cryogen accumulation that reduces the efficiency of heat transfer when compared to spray impingement on a flat surface. Large indentations, however, encourage convective flow within the cryogen pool that mitigates many of the negative effects of liquid layer thickening and improves the heat flux.

Conclusions

Flat surfaces produce the most efficient heat transfer, but once indentation exists (as it does in all clinically relevant cases), larger indentations produce a higher maximum heat flux. This suggests that higher momentum sprays (which produce larger skin indentations for identical spurts) than those in current clinical use may improve CSC efficiency. Lasers Surg. Med. 34:155–163, 2004. © 2004 Wiley‐Liss, Inc.
Polymeric Controlled Release Formulations of Niclosamide for Control of Biomphalaria Alexandrina, the Vector Snail of Schistosomiasis
Authors: Kenawy El‐Refaie , Rizk El‐Sayed
Published: February 2004

Summary: Schistosomiasis is one of the most important public health problems in many developing countries. The present study was conducted to investigate the effect of the polymeric niclosamide formulations against Biomphalaria alexandrina snails, the intermediate host of Schistosoma mansoni in Egypt. Three new polymeric formulations were prepared for the molluscicide niclosamide. The formulations were prepared either by the chemical modifications of poly(glycidyl methacrylate) or by physical entrapment of the niclosamide in calcium alginate beads. The release of the niclosamide from the polymeric formulations was investigated. The activity of the prepared formulations against Biomphalaria alexandrina was investigated. The results obtained revealed higher potency for polymerized niclosamide B3 than B1; the lowest potency was revealed for B2. After an exposure period of 24 hours, LC50 values were 0.073, 0.098 and 1.09 ppm for B3, B1 and B2, respectively. In addition, the molluscicidal potency of the test polymeric niclosamide was age‐dependent, where old snails were more tolerant to the test solutions than young and newly hatched snails. The results also indicated that the molluscicidal activity of B3 was extended for 21 days and 17 days for B1, compared with 5 days for free niclosamide. However, the molluscicidal potency of the polymerized niclosamide was increased after boiling for one hour, and was increased with increasing the pH of the medium to pH 9. In addition, their potency was increased with decreasing the water hardness concentrations (CaCO3).

Molluscicidal activity of free niclosamide and its polymeric formulations vs. exposure time.

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Molluscicidal activity of free niclosamide and its polymeric formulations vs. exposure time.
Biomimetic Polymer/Apatite Composite Scaffolds for Mineralized Tissue Engineering
Authors: Zhang Ruiyun , Ma Peter X.
Published: February 2004

Summary: The material surface must be considered in the design of scaffolds for bone tissue engineering so that it supports bone cells adhesion, proliferation and differentiation. A biomimetic approach has been developed as a 3D surface modification technique to grow partially carbonated hydroxyapatite (the bonelike mineral) in prefabricated, porous, polymer scaffolds using a simulated body fluid in our lab. For the rational design of scaffolding materials and optimization of the biomimetic process, this work focused on various materials and processing parameters in relation to apatite formation on 3D polymer scaffolds. The apatite nucleation and growth in the internal pores of poly(L‐lactide) and poly(D,L‐lactide) scaffolds were significantly faster than in those of poly(lactide‐co‐glycolide) scaffolds in simulated body fluids. The apatite distribution was significantly more uniform in the poly(L‐lactide) scaffolds than in the poly(lactide‐co‐glycolide) scaffolds. After incubation in a simulated body fluid for 30 d, the mass of poly(L‐lactide) scaffolds increased approximately 40%, whereas the mass of the poly(lactide‐co‐glycolide) scaffolds increased by about 15% (see Figure). A higher ionic concentration and higher pH value of the simulated body fluid enhanced apatite formation. The effects of surface functional groups on apatite nucleation and growth were found to be more complex in 3D scaffolds than on 2D films. Surprisingly enough, it was found that carboxyl groups significantly reduced the apatite formation, especially on the internal pore surfaces of 3D scaffolds. These findings are critically important in the rational selection of materials and surface design of 3D scaffolds for mineralized tissue engineering and may contribute to the understanding of biomineralization as well.

SEM micrograph of a poly(L‐lactide) scaffold.

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SEM micrograph of a poly(L‐lactide) scaffold.
Direct Visualization of Straw Cell Walls by AFM
Authors: Yan Lifeng , Li Wan , Yang Jinlong , Zhu Qingshi
Published: February 2004

Summary: The structural relationship of cellulose, hemicellulose, and lignin in plant cell walls is still a mystery needing to be explored. By using atomic force microscopy (AFM) the surface of straw at different layers was directly observed, and the structural characteristics were analyzed by topographic analysis and FT‐IR spectra. It was found that a compact layer of wax covered the outside of the straw, which protects the straw from insects and microorganisms. At the boundary of the primary and second wall there appears a network structure of cellulose and hemicellulose, with some lignin localised on the surface of the network. It is consistent with the model of a cell wall suggested by Vincent. Inside the second cell wall, there is a layer mainly composed of a cellulose crystalline region. High‐resolution AFM observation reveals that the crystalline structure consists of both triclinic and monoclinic unit cells.

An AFM phase image showing the structural relation between cellulose microfibrils, hemicellulose, and lignin in the straw cell wall.

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An AFM phase image showing the structural relation between cellulose microfibrils, hemicellulose, and lignin in the straw cell wall.
Preparation and Characterization of Novel Physically Cross‐linked Hydrogels Composed of Poly(vinyl alcohol) and Amine‐terminated Polyamidoamine Dendrimer
Authors: Wu Xu‐Ye , Huang Shi‐Wen , Zhang Jian‐Tao , Zhuo Ren‐Xi
Published: February 2004

Summary: Poly(vinyl alcohol) (PVA) and polyamidoamine (PAMAM) dendrimers are water‐soluble, biocompatible and biodegradable polymers, which have been widely applied in biomedical fields. In this paper, novel physically cross‐linked hydrogels composed of PVA and amine‐terminated PAMAM dendrimer G6‐NH2 were prepared by cyclic freezing/thawing treatment of aqueous solutions containing PVA and G6‐NH2. The FT‐IR analysis and elemental analysis indicated that PAMAM dendrimer G6‐NH2 was successfully introduced into the formed hydrogels, possibly via hydrogen bonds among hydroxyl groups, amide groups and amino groups in PVA and PAMAM dendrimer in the process of freezing‐thawing cycle. Compared with physically cross‐linked PVA hydrogel, PVA/G6‐NH2 hydrogels show higher swelling ratios and faster re‐swelling rate due to the higher hydrophilicity of PAMAM dendrimer G6‐NH2. Higher contents of G6‐NH2 in PVA/G6‐NH2 hydrogels resulted in higher swelling ratios and faster re‐swelling rates. With increasing freezing/thawing cyclic times, the swelling ratios and re‐swelling rates of PVA/G6‐NH2 hydrogels decreased, which is similar to that of physically cross‐linked PVA hydrogel. Combining the special host property of polyamidoamine dendrimer, these novel physically cross‐linked hydrogels are expected to have potential use in drug delivery, including improving drug‐loading amounts in hydrogels and prolonging drug release time.

Swelling ratios of physically cross‐linked PVA/G6‐NH2‐50 hydrogels prepared by three, six, nine freezing/thawing cycles. The swelling equilibrium experiments were carried out in distilled water at 25 °C.

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Swelling ratios of physically cross‐linked PVA/G6‐NH2‐50 hydrogels prepared by three, six, nine freezing/thawing cycles. The swelling equilibrium experiments were carried out in distilled water at 25 °C.
Cover Picture: Macromol. Biosci. 2/2004
Authors: Yavuz Handan , Denizli Adil
Published: February 2004

Cover: Representative SEM micrographs of polyamide hollow‐fibers; (a) inner surface; (b) outer surface.

Further details can be found in the Full Paper by H. Yavuz and A. Denizli* on page 84.
UV Laser‐Induced Gas‐Phase Copolymerization of Carbon Disulfide and Ethene
Authors: Tomovska Radmila , Urbanová Markéta , Fajgar Radek , Bastl Zdeněk , Šubrt Jan , Pola Josef
Published: February 2004

Summary: The laser irradiation at 193 nm of a gaseous mixture of carbon disulfide and ethene induces the copolymerization of both compounds and affords the chemical vapour deposition of a C/S/H polymer, the composition of which indicates the reaction between two to three CS2 molecules and one C2H4 molecule. Polymer structure is interpreted on the basis of X‐ray photoelectron and FT‐IR spectra as consisting of >CS, >CC<, CH2CH2, (CC)SnC4 − n, C(CS)S, S(CS)S, and CSSC configurations. The gas‐phase copolymerization of carbon disulfide and ethene represents the first example of such a reaction between carbon disulfide and a common monomer.

Scheme showing the expected reaction of excited CS2 molecules with other CS2 molecules to form dimers, which then react with another CS2 molecule or add to ethene.

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Scheme showing the expected reaction of excited CS2 molecules with other CS2 molecules to form dimers, which then react with another CS2 molecule or add to ethene.
Differences between Ziegler–Natta and Single‐Site Linear Low‐Density Polyethylenes as Characterized by Inverse Gas Chromatography
Authors: Zhao Liyan , Choi Phillip
Published: February 2004

Summary: Zero‐pressure weight‐fraction‐based Henry's constants $(H_{{\rm 12}}^0 )$ of two alkanes, two alkenes, and benzene in Ziegler–Natta (ZN) and single‐site (ss) linear low‐density polyethylenes (LLDPE) with different average branch contents, molecular‐weight averages ($\overline M _{\rm n}$ and $\overline M _{\rm w}$), and polydispersity indices (PDI) were measured in the temperature range of 170 to 230 °C using the technique of inverse gas chromatography. For both types of LLDPEs, the measured $H_{{\rm 12}}^0$ was insensitive to molecular weight and PDI. However, the branch content dependence differed significantly. In particular, ZN‐LLDPE exhibited a strong branch content dependence on $H_{{\rm 12}}^0$ while ss‐LLDPE did not. In fact, depending on the temperature and solvent used, $H_{{\rm 12}}^0$ of ZN‐LLDPE could drop as much as 21% with an increase in an average branch content from 13 to 35 branches per 1 000 backbone carbons, while the differences of $H_{{\rm 12}}^0$ between ss‐LLDPEs with comparable differences in branch content were well within experimental uncertainties (5%). This observation is also supported by the fact that comparable ZN‐ and ss‐LLDPEs exhibited larger differences in $H_{{\rm 12}}^0$ at higher average branch contents. The above findings strongly suggested that the liquid morphologies of ZN‐ and ss‐LLDPEs differ considerably. In particular, the local chain conformation and free volume characteristics (i.e., the size distribution and/or spatial distribution of the free volume holes) of them are rather different. Such differences become more pronounced at higher temperatures.

The weight‐fraction‐based Henry's constant of n‐hexane and hex‐1‐ene in Ziegler–Natta (ZN) and single‐site (ss) linear low‐density polyethylenes (LLDPE) with different average branch contents.

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The weight‐fraction‐based Henry's constant of n‐hexane and hex‐1‐ene in Ziegler–Natta (ZN) and single‐site (ss) linear low‐density polyethylenes (LLDPE) with different average branch contents.
Transcrystalline Morphology of an in situ Microfibrillar Poly(ethylene terephthalate)/Poly(propylene) Blend Fabricated through a Slit Extrusion Hot Stretching‐Quenching Process
Authors: Li Zhong‐Ming , Li Liang‐Bin , Shen Kai‐Zhi , Yang Wei , Huang Rui , Yang Ming‐Bo
Published: February 2004

Summary: Isotactic poly(propylene) (iPP) transcrystallites are obtained in in situ microfibrillar polyethylene terephthalate (PET)/iPP blends during a slit extrusion‐hot stretching‐quenching process. Based on morphological information from X‐ray scattering and microscopy, three nucleation origins are proposed in microfibrillar reinforced blends under an elongational flow field: (a) the classical row nuclei model; (b) fiber nuclei; (c) nuclei induced by fiber assistant alignment. The last model provides a natural explanation for the case that transcrystallites only occur in some microfiber reinforced blends under flow rather than without the external field.

AFM image for the transcrystalline layer of the microfibrillar blend.

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AFM image for the transcrystalline layer of the microfibrillar blend.
Soluble Polyamides and Polyimides Functionalized with Benzo‐15‐Crown‐5‐Pendant Groups
Authors: Maya Eva M. , Lozano Angel E. , de la Campa Jose G. , de Abajo Javier
Published: February 2004

Summary: A new diamine monomer containing a crown ether was made to react with commercial diacid chlorides and dianhydrides to yield new aromatic polyamides and polyimides. The crown ether moiety was introduced as a pendant group so that the polymers showed enhanced solubility in organic solvents, good thermal properties (high transition temperatures and high thermal stability), and good film‐forming ability.

The new aromatic polyamides and polyimides bearing a benzo‐15‐crown‐5‐pendant group synthesized here.

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The new aromatic polyamides and polyimides bearing a benzo‐15‐crown‐5‐pendant group synthesized here.
Living Ring‐Opening Metathesis Polymerization of Norbornenes Containing Acetyl‐Protected Carbohydrates Using Well‐Defined Molybdenum and Ruthenium Initiators
Authors: Nomura Kotohiro , Sakai Ichiro , Imanishi Yukio , Fujiki Michiya , Miyamoto Yoshitaka
Published: February 2004

Summary: Homopolymers and diblock copolymers that contain maltose or glucose residues have been prepared by ring‐opening metathesis polymerization of norbornene derivatives using a molybdenum–alkylidene initiator, Mo(CHCMe2Ph)(N‐2,6‐iPr2C6H3)(OtBu)2 (A). These polymerizations took place not only in a living fashion ($\overline M _{\rm w} /\overline M _{\rm n}$ = < 1.2) but also with almost quantitative initiation. Two types of ruthenium initiators, (Cy3P)2RuCl2(CHPh) (B) and (IMesH2)(Cy3P)RuCl2(CHPh) (C), have also been used to compare initiator performance under the same conditions.

Structures for the polymers studied here.

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Structures for the polymers studied here.
A Peptide‐Cyclodextrin Hybrid System Capable of Detecting Guest Molecules Utilizing Fluorescence Resonance Energy Transfer
Authors: Yana Dewi , Takahashi Tsuyoshi , Mihara Hisakazu , Ueno Akihiko
Published: February 2004

Summary: A cyclodextrin‐peptide hybrid bearing coumarin and fluorescein on the peptide side chain has been designed and synthesized as a novel chemosensor molecule utilizing fluorescence resonance energy transfer (FRET). Inclusion of coumarin into β‐cyclodextrin protects this system against fluorescent quenching, so that FRET occurs though donor and acceptor moieties nearby. FRET is diminished upon the addition of various guest compounds, suggesting that this system is useful for detecting molecules in aqueous solution.

A cyclodextrin‐peptide hybrid bearing coumarin and fluorescein on the peptide side chain.

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A cyclodextrin‐peptide hybrid bearing coumarin and fluorescein on the peptide side chain.
Preparation of Stable Colloidal Crystals and Macroporous Materials Using Diazoresin as a Thermosetting Agent
Authors: Cong Hailin , Cao Weixiao
Published: February 2004

Summary: Two kinds of stable colloidal crystals have been prepared from polymeric or SiO2 colloids in the presence of diazoresin (DR) as a thermosetting agent combining thermal treatment. Following the decomposition of N groups of DR under heating, the ionic bonds between the DR molecules and colloids change to covalent bonds and the colloidal crystals become very stable toward ultrasonic washing. The colloids were then removed by tetrahydrofuran (THF) in the case of organics or by hydrofluoric acid (HF) for the inorganics to leave the macroporous DR materials.

Reactions between the DR molecules and the colloids during thermal treatment.

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Reactions between the DR molecules and the colloids during thermal treatment.
Cationic Spherical Polyelectrolyte Brushes as Nanoreactors for the Generation of Gold Particles
Authors: Sharma Geeta , Ballauff Matthias
Published: February 2004

Summary: If long polyelectrolyte chains are attached densely to colloidal latex particles, a spherical polyelectrolyte brush results. These spherical polyelectrolytes are dispersed in water and carry a high charge. We demonstrate that these systems can be used to immobilize ions of heavy metals, such as gold, as counter‐ions. Reduction of these ions leads to metallic nanoparticles. In this way the brush layer attached to the surface of the particles becomes a “nanoreactor” that may be used for chemical conversions of the metal ions. We show that the reduction of AuCl ions within these nanoreactors leads to well‐defined and rather monodisperse gold nanoparticles that are attached to the surface of the core. A stable dispersion of polymeric core particles with attached nanoparticles results. All results reported here suggest that chemical reactions of ions immobilized in spherical polyelectrolyte brushes provide a new route to composite particles of inorganic and organic materials.

Transmission electron micrograph of gold particles on a core‐shell system.

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Transmission electron micrograph of gold particles on a core‐shell system.
Preparation, Structure, and Properties of Starch/Rubber Composites Prepared by Co‐Coagulating Rubber Latex and Starch Paste
Authors: Wu You‐Ping , Ji Mei‐Qin , Qi Qing , Wang Yi‐Qing , Zhang Li‐Qun
Published: February 2004

Summary: Several rubber/starch composites in which the starch particles are in an amorphous state and are smaller than 1 μm, prepared by directly mixing and co‐coagulating rubber latex and starch paste, exhibit higher hardness, stress at 100%, tensile strength, and tear strength relative to the corresponding rubber/starch composites prepared by direct blending.

TEM micrograph of starch/SBR composite.

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TEM micrograph of starch/SBR composite.
Atom Transfer Radical Polymerization of N‐Isopropylacrylamide
Authors: Masci Giancarlo , Giacomelli Laura , Crescenzi Vittorio
Published: February 2004

Summary: Controlled polymerization of N‐isopropylacrylamide (NIPAAM) was achieved by atom transfer radical polymerization (ATRP) using ethyl 2‐chloropropionate (ECP) as initiator and CuCl/tris(2‐dimethylaminoethyl)amine (Me6TREN) as a catalytic system. The polymerization was carried out in DMF:water 50:50 (v/v) mixed solvent at 20 °C. The first order kinetic plot was linear up to 92% conversion. Controlled molecular weights up to 2.2 × 104 and low polydispersities (1.19) were obtained. The living character of the polymerization was also demonstrated by self‐blocking experiments. Block copolymers with N,N‐dimethylacrylamide (DMAAM) and 3‐sulfopropyl methacrylate (SPMA) were successfully prepared.

Molecular weights and polydispersities of polyNIPAAM versus NIPAAM conversion for two different degrees of polymerization.

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Molecular weights and polydispersities of polyNIPAAM versus NIPAAM conversion for two different degrees of polymerization.
Gelation Studies on a Radical Chain Cross‐Linking Copolymerization Process: Comparison of the Critical Exponents Obtained by Dynamic Light Scattering and Rheology
Authors: Richter Sven , Boyko Volodymyr , Schröter Klaus
Published: February 2004

Summary:The sol–gel transition of a radical chain cross‐linking copolymerization system [N‐vinylcaprolactam/2‐hydroxylethyl methacrylate/allyl methacrylate] has been studied using in situ time‐resolved dynamic light scattering (DLS) and in situ rheology. A critical dynamic behavior was observed near the sol–gel transition, which was characterized by the presence of a power‐law spectra over three decades in the time–intensity correlation functiong2(t) − 1 ∼ t−μand over two decades in the oscillatory shear experimentG′(ω) ∼ G″(ω) ∼ ωn. A comparison of the obtained critical exponentsμ ≈ 0.62 andn ≈ 0.75 was made. The theory predicts a relationship between these exponents, but up to now no experimental comparison has been done. The experimental results favor the percolation model, with a fractal dimensiondfof the gel clusters of 1.67.

Double‐logarithmic plot of time–intensity correlation functionsg2(t) − 1 versus the delay timet.

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Double‐logarithmic plot of time–intensity correlation functionsg2(t) − 1 versus the delay timet.
Cover Picture: Macromol. Rapid Commun. 4/2004
Authors: Richter Sven , Boyko Volodymyr , Schröter Klaus
Published: February 2004

Cover: The sol‐gel transition is a very important critical phenomenon. The gelation of a radical chain cross‐linking copolymerization system has been studied by using in situ time‐resolved dynamic light scattering and in situ rheology. Critical dynamical behavior was observed near the sol‐gel transition, which is characterized by the presence of power‐law spectra in the oscillatory shear experiment (upper left figure of the cover picture) and in the time‐intensity correlation function (lower right figure of the cover picture). A experimental comparison of the critical exponents obtained from both methods was done for the first time.

Further details can be found in the Communication by S. Richter,* V. Boyko, and K. Schröter on page 542.
Crossregulation of NF‐κB by the APC/GSK‐3β/β‐catenin pathway
Authors: Deng Jiong , Xia Weiya , Miller Stephanie A. , Wen Yong , Wang Hong‐Ying , Hung Mien‐Chie
Published: February 2004

Glycogen synthase kinase‐3β (GSK‐3β) and adenomatous polyposis coli (APC) play an important role in the regulation of β‐catenin. Inhibition of or defects in their functions can lead to activation of β‐catenin. β‐catenin has been recently found to interact with and inhibit nuclear factor kappa B (NF‐κB). However, the regulatory roles of GSK‐3β/APC on the NF‐κB signaling pathway are unknown because of their diverse effects. In this study, we investigated whether GSK‐3β/APC might regulate NF‐κB activity through β‐catenin. We found that inhibition of GSK‐3β suppressed NF‐κB activity, whereas reexpression of APC restored NF‐κB activity in APC mutated cells. The regulatory effects were through β‐catenin because depletion of β‐catenin with small interfering RNA (siRNA) in the same systems reversed the effects. The regulatory relationship was further supported by the analysis of primary breast tumor tissues in vivo in which NF‐κB target TRAF1 was inversely correlated with activated β‐catenin. Thus, APC/GSK‐3β, through β‐catenin, may crossregulate NF‐κB signaling pathway. © 2004 Wiley‐Liss, Inc.
Relationship between the radiosensitizing effect of wortmannin, DNA double‐strand break rejoining, and p21WAF1 induction in human normal and tumor‐derived cells
Authors: Mirzayans Razmik , Pollock Scott , Scott April , Enns Louise , Andrais Bonnie , Murray David
Published: February 2004

Wortmannin (WM) is a potent inhibitor of the catalytic sub‐unit of DNA‐PK, which is involved in one pathway of DNA double‐strand break (DSB) rejoining, and of ATM, which functions upstream in the p53 signaling pathway. WM is known to be an efficient radiosensitizer in a variety of mammalian cell types, to inhibit DSB rejoining following exposure to supralethal doses (≥30 Gy) of ionizing radiation, and to abrogate the induction of p53 at early times after radiation exposure. We report here that WM is a more effective radiosensitizer in A549 human lung carcinoma cells than in normal human fibroblasts (NHFs). In addition, WM strongly inhibits DSB rejoining in A549 cells exposed to relatively low doses (e.g., 10 Gy) of ionizing radiation, without having any detectable effect in NHFs. We further demonstrate that WM significantly potentiates the induction of p21WAF1, a p53‐regulated gene that encodes for a key mediator of cell‐cycle/growth arrest, when determined at late times (e.g., 24 h) after irradiation. This late WM‐dependent potentiation of p21WAF1 induction following radiation exposure is observed in NHFs and in the p53 wild‐type tumor cell lines A549, A172, and SKNSH, but not in the p53‐deficient tumor cell lines DLD‐1, HeLa, and SKNSH‐E6. We conclude that: (i) inhibition of DSB rejoining by WM may be an important contributor to its radiosensitizing effect in A549 cells but not in NHFs; and (ii) radiosensitization of p53‐proficient human cells by WM may in part be associated with the delayed induction of p21WAF1, which can lead to a sustained growth‐arrested phenotype resembling senescence. © 2004 Wiley‐Liss, Inc.
Inactivation of the cyclin‐dependent kinase inhibitor 2A (CDKN2A) gene in squamous cell carcinoma of the larynx
Authors: Smigiel Robert , Sasiadek Maria , Krecicki Tomasz , Ramsey David , Jagielski Jozef , Blin Nikolaus
Published: February 2004

Defects in the system controlling the cell cycle can lead an increased proliferation of cancer cells. The aim of our study was to analyze the relationship between genetic changes leading to inactivation of the CDKN2A gene and subsequent alteration of protein expression in squamous cell cancer of the larynx (SCCL) in connection with the clinical and histopathological course of the disease. Analysis was carried out on DNA isolated from the blood and primary larynx cancer cells of 62 patients. To investigate loss of heterozygosity (LOH), PCR fragment analysis was applied. The size and quantity of fluorescent PCR products were evaluated in an automated sequencer. Specific chemical methylation with sodium bisulfite in a sequential PCR reaction (MSP) was applied to analyze promoter methylation. Cancer tissue sections served to determine the level of protein expression with immunohistochemical (IHC) staining and commercial antibodies. LOH at the CDKN2A locus was observed in 55.35% of the informative cases. Aberrant methylation was found in 37.5% and a decreased level of protein expression observed in 45% of all informative cases. Whenever P16 expression was decreased, LOH and promoter hypermethylation at CDKN2A were observed with a frequency of 73.33% and 80.95%, respectively (Fisher's test, P < 0.005). Sixty‐nine percent of G3 tumors had at least one genetic alteration at CDKN2A, compared with 40.9% of G1 cancers. The results indicate that CDKN2A inactivation played a significant role in the development of squamous cell carcinoma of the larynx. © 2004 Wiley‐Liss, Inc.
Caspase‐8 levels affect necessity for mitochondrial amplification in death ligand‐induced glioma cell apoptosis
Authors: Knight Melissa J. , Riffkin Christopher D. , Ekert Paul G. , Ashley David M. , Hawkins Christine J.
Published: February 2004

Fifty percent of high‐grade glioma patients die within a year of diagnosis and less than two percent survive five years postdiagnosis. Elucidating apoptosis signaling pathways may assist in designing better adjuvant therapies. Preliminary characterizations suggested that glioma cells may either employ mitochondrial‐independent or ‐dependent death receptor‐induced apoptotic pathways, characteristic of cells termed type I and type II, respectively. In the present study, we generated panels of clonal transfectants overexpressing various levels of Bcl‐2, in two parental glioma cell lines. These cells were used to explore molecular factors determining the necessity for mitochondrial amplification of death receptor signaling. Moderate Bcl‐2 expression was sufficient to render one glioma cell line (D270) resistant to apoptosis induced by Fas ligand or TRAIL, consistent with these cells being type II. However, expression of even very high levels of Bcl‐2 in a second line (D645) did not affect death ligand sensitivity, indicative of a type I phenotype. D270 cells expressed much less caspase‐8 protein than D645 cells. Enforced overexpression of caspase‐8 (or cytoplasmic Diablo/Smac) in D270 cells overcame Bcl‐2 inhibition of death ligand‐induced apoptosis, converting them from type II to type I. This indicates that caspase‐8 levels can influence the requirement for mitochondrial involvement in death receptor apoptotic signaling in glioma cells. © 2004 Wiley‐Liss, Inc.
Tools for anti‐inflammatory drug design: In vitro models of leukocyte migration
Authors: Frow Emma K. , Reckless Jill , Grainger David J.
Published: February 2004

Inhibiting leukocyte recruitment is now a major focus in the design of novel anti‐inflammatory drugs. Following the identification of lead compounds from conventional high‐throughput screens using appropriate receptors or enzymes, it is important to validate the action of the compounds in a suitable in vitro model of leukocyte migration. Here, we review a range of different experimental approaches to modelling leukocyte migration, and identify the multi‐well filter migration assay as the best compromise between the amount of resources required to screen multiple compounds and the amount of information gained about the effects of the compounds on cell movement behavior. However, there are pitfalls in the interpretation of data obtained using the multi‐well filter migration assay, which arise from the imperfect correlation between the number of cells undergoing migration and the inhibitory activity of the test substances. We examine a number of such pitfalls and provide practical approaches to mitigate these problems as far as possible. We recommend a general strategy for screening inhibitors of cell migration using in vitro functional assays. While being more resource intensive than surrogate measures such as calcium flux, functional approaches nevertheless provide superior correlations with anti‐inflammatory activity in vivo. © 2004 Wiley Periodicals, Inc. Med Res Rev, 24, No. 3, 276–298, 2004
Liposome/water lipophilicity: Methods, information content, and pharmaceutical applications
Authors: van Balen Georgette Plemper , Martinet Catherine a Marca , Caron Giulia , Bouchard Géraldine , Reist Marianne , Carrupt Pierre‐Alain , Fruttero Roberta , Gasco Alberto , Testa Bernard
Published: February 2004

This review discusses liposome/water lipophilicity in terms of the structure of liposomes, experimental methods, and information content. In a first part, the structural properties of the hydrophobic core and polar surface of liposomes are examined in the light of potential interactions with solute molecules. Particular emphasis is placed on the physicochemical properties of polar headgroups of lipids in liposomes. A second part is dedicated to three useful methods to study liposome/water partitioning, namely potentiometry, equilibrium dialysis, and 1H‐NMR relaxation rates. In each case, the principle and limitations of the method are discussed. The next part presents the structural information encoded in liposome/water lipophilicity, in other words the solutes' structural and physicochemical properties that determine their behavior and hence their partitioning in such systems. This presentation is based on a comparison between isotropic (i.e., solvent/water) and anisotropic (e.g., liposome/water) systems. An important factor to be considered is whether the anisotropic lipid phase is ionized or not. Three examples taken from the authors' laboratories are discussed to illustrate the factors or combinations thereof that govern liposome/water lipophilicity, namely (a) hydrophobic interactions alone, (b) hydrophobic and polar interactions, and (c) conformational effects plus hydrophobic and ionic interactions. The next part presents two studies taken from the field of QSAR to exemplify the use of liposome/water lipophilicity in structure–disposition and structure–activity relationships. In the conclusion, we summarize the interests and limitations of this technology and point to promising developments. © 2004 Wiley Periodicals, Inc. Med Res Rev, 24, No. 3, 299–324, 2004
Melanocortin ligands: 30 years of structure–activity relationship (SAR) studies
Authors: Holder Jerry Ryan , Haskell‐Luevano Carrie
Published: February 2004

The challenge of peptide and peptidomimetic research is the development of methods and techniques to improve the biological properties of native peptides and to convert peptide ligands into non‐peptide compounds. Improved biological properties of peptides includes enhancement of stability, potency, and receptor selectivity, for both in vivo and in vitro applications. The design of a ligand with specific activity and desired biological properties is a complex task, and, to accomplish this objective, knowledge about putative interactions between a ligand and the corresponding receptor will be valuable. This includes interactions for both the binding and signal transduction processes. Structure–activity relationship (SAR) studies involve systematic modification of a lead peptide and are designed to provide insight into potential interactions involved in the formation of the ligand–receptor complex. It is desirable to have knowledge about both favorable and unfavorable processes that may occur in putative ligand–receptor interactions that result in either receptor stimulation or inhibition. Herein, we discuss various SAR studies that have involved melanocortin peptides over three decades and the information these studies have provided to the melanocortin field. © 2004 Wiley Periodicals, Inc. Med Res Rev, 24, No. 3, 325–356, 2004
Peptide‐based radiopharmaceuticals: Future tools for diagnostic imaging of cancers and other diseases
Authors: Okarvi S.M.
Published: February 2004

An Erratum has been published for this article in Medicinal Research Reviews 2004;24:685–686.

Small synthetic receptor‐binding peptides are the agents of choice for diagnostic imaging and radiotherapy of cancers due to their favorable pharmacokinetics. Molecular modification techniques permit the synthesis of a variety of bioactive peptides with chelating groups, without compromising biological properties. Various techniques have been developed that allow efficient and site‐specific labeling of peptides with clinically useful radionuclides such as 99mTc, 123I, 111In, and 18F. Among them, 99mTc is the radionuclide of choice because of its excellent chemical and imaging characteristics. Recently, many 99mTc‐labeled peptides have proven to be useful imaging agents. Beside 99mTc‐labeled peptides, several peptides radiolabeled with 111In and 123I have been prepared and characterized. In addition, 18F‐labeled peptides hold clinical potential due to their ability to quantitatively detect and characterize a variety of human diseases using positron‐emission tomography. The availability of this wide range of peptides labeled with different radionuclides offers multiple diagnostic and therapeutic applications. Various receptors are over‐expressed in particular tumor types and peptides binding to these receptors can be used to visualize tumor lesions scintigraphically. Thus, radiolabeled peptides have potential use as carriers for the delivery of radionuclides to tumors, infarcts, and infected tissues for diagnostic imaging and radiotherapy. Many radiolabeled peptides are currently under investigation to determine their potential as imaging agents. These peptides are designed mainly for thrombus, tumor, and infection/inflammation imaging. This article presents recent developments in small synthetic peptides for imaging of thrombosis, tumors, and infection/inflammation. © 2004 Wiley Periodicals, Inc. Med Res Rev, 24, No. 3, 357–397, 2004
Expression of the bovine aromatase cytochrome P450 gene (Cyp19) is primarily regulated by promoter 2 in bovine follicles and by promoter 1.1 in corpora lutea
Authors: Lenz Solvig , Pöhland Ralf , Becker Frank , Vanselow Jens
Published: February 2004

Follicular development and differentiation are closely associated with increasing steroidogenesis. During the present study transcript concentration of Cyp19, Cyp11A1, and 3β‐hydroxysteroid dehydrogenase delta (3β‐HSD) encoding the steroidogenic enzymes P450arom, P450SCC, and 3β‐HSD were determined by real‐time PCR in bovine granulosa cells (GC) as potential markers for follicular differentiation. Ovaries were collected from a local abattoir (experiment 1) and from synchronized animals at day 4 of estrus cycle (experiment 2). To study effects of luteinization, steroidogenic transcripts were also quantified in corpora lutea (CL) 4 and 20 days after fertilization. In most follicles, all three steroidogenic transcripts were detected, however, at very different concentration. Expression of 3β‐HSD and Cyp11A1 was highly significantly co‐regulated and showed a significant correlation with follicular size. Contrary, Cyp19 expression was extremely variable even in follicles of similar size. Cyp19 transcripts were derived predominantly from promoter P2 and less abundant from promoters P1.1 and P1.5. After luteinization, the concentration of 3β‐HSD and Cyp11A1 transcripts increased (75‐fold and fivefold, respectively) whereas the Cyp19 transcript level dropped (160‐fold). Residual Cyp19 transcripts in CL were almost exclusively derived from P1.1. The data indicate that Cyp19 expression in GC is predominantly regulated by P2 and to a minor extend by P1.1, whereas P1.1 is almost exclusively responsible for residual Cyp19 expression in CL. Correlation analyses suggest that the expression of 3β‐HSD and Cyp11A1 primarily depend on the size of follicles whereas the concentration of P2 derived Cyp19 transcripts in GC is a marker for follicular differentiation towards selection and dominance. Mol. Reprod. Dev. 67: 406–413, 2004. © 2004 Wiley‐Liss, Inc.