bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of the mechanical properties of skin with ballistometer and suction cup
Authors: Jemec Gregor B. E. , Selvaag Edgar , Ågren Magnus , Wulf Hans Christian
Published: March 2003

Background:

There is no consensus on the methodology for describing the mechanical properties of human skin in vivo. Current descriptions are generally method dependent.

Method: The mechanical properties of palmar skin of the hypothenar as well as dorsal and ventral forearm skin were studied in 17 healthy volunteers. Two methods were used: ballistometry [Dia‐stron Torsional Ballistometer (Diastron Ltd., Andover, UK)] and suction cup [The Dermaflex machine (Cortex Technology, Hadsund, Denmark)].

Results: A moderate degree of correlation was found between the methods (rs=0.315–0.540), while internal correlation between different measures obtained with one method was higher (rs=0.375–0.967). The suction cup method parameters (distensibility and elasticity) correlated significantly with the ballistometry parameters (indentation, alpha, area and coefficient of restitution), while the hysteresis did not correlate to ballistometry parameters. The coefficient of variation of both methods (CV=0.02–0.35) was within the range obtained with other non‐invasive methods, e.g., TEWL. Regional differences were identified with both methods, while only the suction cup method identified age‐related changes.

Conclusions: The results suggest that while both methods may be useful, they describe related but not identical aspects of skin mechanics. The differences in measuring principle suggest that the suction cup method predominantly measures elasticity, while the ballistometer predominantly appears to measure stiffness. Hysteresis may be a unique measure of skin viscosity. Additional studies, however, are needed to specify the clinical significance of the various measures of skin mechanics.
Instrumental and dermatologist evaluation of the effect of glycerine and urea on dry skin in atopic dermatitis
Authors: Lodén M. , Andersson A.‐C. , Andersson C. , Frödin T. , Öman H. , Lindberg M.
Published: March 2003

Background/aims: Moisturising creams are useful treatment adjuncts in inflammatory dermatoses and have beneficial effects in the treatment of dry, scaly skin. The effects on dryness and skin permeability of a new moisturising cream with 20% glycerine was compared with its placebo and with a medicinally authorised cream with 4% urea (combined with 4% sodium chloride) in the treatment of dry skin.

Methods: Patients (n=109) with atopic dermatitis were treated for 30 days with a moisturiser in a randomised, parallel and double‐blind fashion. Transepidermal water loss (TEWL) and skin capacitance were assessed instrumentally, and changes in the dryness of the skin were assessed by the dermatologist.

Results: No difference in TEWL was found between glycerine treatment and its placebo, whereas a lower value was found in the urea‐treated area compared to the glycerine‐treated area. No difference in skin capacitance was found. The clinical assessment of dryness showed urea to be superior to glycerine in treating the condition.

Conclusions: Moisturising creams are different, not only with respect to composition but also with respect to their influence on skin as a barrier to water in patients with atopic dermatitis.
Thermal imaging in acute herpes zoster or post‐zoster neuralgia
Authors: Ammer K. , Schartelmueller T. , Melnizky P.
Published: March 2003

Background/aims: Asymmetry of normal skin temperature patterns has been reported in patients with herpetic disorders. The aim of the study was to describe the temperature distribution in patients suffering from acute herpes zoster or post‐herpetic neuralgia.

Methods: Biographic data, including age, gender and time of onset of the skin lesions, were recorded. The distribution of pain was investigated by pain mapping, and the intensity of pain and dysesthesia was quantified by a visual analogue scale. Infrared thermal images of the affected body regions were performed in all possible views using either an Agema 870 or a NEC San‐ei Thermotracer.

Results: The mean temperature difference between the affected and the unaffected sides of the body in all patients was 0.52±0.30°C. Higher temperatures were detected in early cases with a disease duration of 1–9 days (mean temperature difference: 0.62±0.36°C) than in patients with pain scores greater than 79 (mean temperature difference: 0.48±0.33°C). Only 6 of 57 patients presented with a temperature difference between the affected side and contralateral side of less than 0.2°C.

Conclusion: Thermal asymmetry of the skin is a common finding in patients with acute herpes. However, the thermal patterns seem to correlate better with the duration of the disease than with the intensity of pain.
Scrotal temperatures do not differ among young boys wearing disposable or reusable diapers
Authors: Grove G. L. , Grove M. J. , Bates N. T. , Wagman L. M. , Leyden J. J.
Published: March 2003

Background/aims: This study investigated the effect of specific, commonly used diaper types on scrotal temperatures in normal healthy, young boys. These included both modern disposable and reusable diapers as well as various types of protective outer coverings that are in common use in both North America and Europe

Methods: Scrotal and skin surface temperatures were continuously monitored in healthy, young males using a computerized data‐logging system based on temperature probes specifically designed for paediatric studies. These systems could be used either tethered to the PC or made completely portable depending upon the age and activity of the child being measured. Based on our results from several pilot studies, it became clear that the best way to determine if disposable and reusable diapers differ with regard to their impact on scrotal temperatures is to run these comparisons under controlled laboratory conditions where ‘diaper type’ was the primary variable. A 2‐h time period was chosen to ensure that sufficient time had elapsed for thermal equilibrium to be established under the diapers. We also felt it necessary to study the impact of urination and simulated this condition over the last 15 min using standardized methods. In addition to the skin surface temperatures, we also measured the temperature of the tympanic membrane using an infrared thermometer as an estimate of ‘core’ temperature for each individual at various times during the session.

Results and Conclusions: In this study, we have clearly shown that scrotal temperatures are the same whether the child is wearing disposable or reusable cloth diapers with a protective cover. The only situation in which scrotal temperatures were found to be lower is when the cloth diaper is used alone without a protective cover but this is not representative of how these products are actually used. We also found that on average scrotal temperatures are significantly lower than core for each diaper type. Occasionally, we did see individuals in which the maximal scrotal temperatures approached core temperatures but in every case the thermal sensors were soiled by a bowel movement. We also found that skin surface temperatures increased not only when covered by a diaper but also due to the thermal insulation provided by outer garments and blankets.
A non‐invasive tape absorption method for recovery of inflammatory mediators to differentiate normal from compromised scalp conditions
Authors: Perkins M. A. , Cardin C. W. , Osterhues M. A. , Robinson M. K.
Published: March 2003

Background/aims:
A simple non‐invasive tape (SebutapeTM) adsorption method was used to recover inflammatory proteins from normal and compromised human scalp (i.e. dandruff and seborrheic dermatitis) in order to assess the inflammatory and immunologic changes relevant to these clinical conditions.

Methods: The scalps of subjects identified by a dermatologist as having either dandruff (n = 18), seborrheic dermatitis (n = 19) or normal scalp (n = 16) were visually graded to obtain total adherent scalp flaking scores (TASFS). Sebutape samples were then collected from both the high and low TASFS scalp sites using a one‐minute tape application. To recover inflammatory molecules, tapes were extracted in buffered saline with sonication and the tape extracts analysed using commercial immunoassay methods for pro‐inflammatory cytokines [i.e. interleukin‐1α (IL‐1α), IL‐1β, IL‐1 receptor antagonist (IL‐1ra), IL‐8 and tumor necrosis factor‐α (TNF‐α)] and the immunologic cytokines [i.e. IL‐2, IL‐4, IL‐10, IL‐12, IL‐15 and interferon gamma (IFN‐γ)]. Nitric oxide (NO) was also assayed on tape extracts using the Greiss reaction. To account for differences in protein loading on the tapes all cytokine and NO results were normalized using the total protein (TP) amounts recovered in tape extracts.

Results: The IL‐1α/TP levels recovered from dandruff and seborrheic scalps were significantly decreased (P = 0.03) compared to normal appearing scalp levels. The scalp levels of IL‐1ra/TP and the ratio of IL‐ra to IL‐1α were significantly (P = 0.002) or directionally (P = 0.07) higher in seborrheic dermatitis scalps and dandruff scalps, respectively, compared to normal scalps. The IL‐1ra and the IL‐1ra/IL‐1α ratio values correlated well with the TASFS. The TNF‐α/TP levels recovered from dandruff scalps were significantly higher (P = 0.02) than levels recovered from seborrheic dermatitis and normal scalp subjects. IL‐2/TP was significantly increased (P = 0.01) and IFN‐γ and NO significantly decreased (P = 0.05) in the seborrheic dermatitis scalp samples compared to normal controls.

Conclusion: The Sebutape method has proven useful for distinguishing normal from diseased scalp conditions. The cytokines recovered from the scalp tape samples showed distinct patterns that differentiated dandruff, seborrheic dermatitis and normal scalp populations. These methods may also prove useful for monitoring the clinical efficacy of therapeutic actives for treating dandruff and seborrhea.
The Tail Domain of Myosin M Catalyses Nucleotide Exchange on Rac1 GTPases and Can Induce Actin‐Driven Surface Protrusions
Authors: Geissler Heidrun , Ullmann Ronald , Soldati Thierry
Published: March 2003

Members of the myosin superfamily play crucial roles in cellular processes including management of the cortical cytoskeleton, organelle transport and signal transduction. GTPases of the Rho family act as key control elements in the reorganization of the actin cytoskeleton in response to growth factors, and other functions such as membrane trafficking, transcriptional regulation, growth control and development. Here, we describe a novel unconventional myosin from Dictyosteliumdiscoideum, MyoM. Primary sequence analysis revealed that it has the appearance of a natural chimera between a myosin motor domain and a guanine nucleotide exchange factor (GEF) domain for Rho GTPases. The functionality of both domains was established. Binding of the motor domain to F‐actin was ATP‐dependent and potentially regulated by phosphorylation. The GEF domain displayed selective activity on Rac1‐related GTPases. Overexpression, rather than absence of MyoM, affected the cell morphology and viability. Particularly in response to hypo‐osmotic stress, cells overexpressing the MyoM tail domain extended massive actin‐driven protrusions. The GEF was enriched at the tip of growing protuberances, probably through its pleckstrin homology domain. MyoM is the first unconventional myosin containing an active Rac‐GEF domain, suggesting a role at the interface of Rac‐mediated signal transduction and remodeling of the actin cytoskeleton.
Traffic Pattern of Cystic Fibrosis Transmembrane Regulator through the Early Exocytic Pathway
Authors: Bannykh Sergei I. , Bannykh Galina I. , Fish Kenneth N. , Moyer Bryan D. , Riordan John R. , Balch William E.
Published: March 2003

The pathway of transport of the cystic fibrosis transmembrane regulator (CFTR) through the early exocytic pathway has not been examined. In contrast to most membrane proteins that are concentrated during export from the ER and therefore readily detectable at elevated levels in pre‐Golgi intermediates and Golgi compartments, wild‐type CFTR could not be detected in these compartments using deconvolution immunofluorescence microscopy. To determine the basis for this unusual feature, we analyzed CFTR localization using quantitative immunoelectron microscopy (IEM). We found that wild‐type CFTR is present in pre‐Golgi compartments and peripheral tubular elements associated with the cis and trans faces of the Golgi stack, albeit at a concentration 2‐fold lower than that found in the endoplasmic reticulum (ER). ΔF508 CFTR, a mutant form that is not efficiently delivered to the cell surface and the most common mutation in cystic fibrosis, could also be detected at a reduced concentration in pre‐Golgi intermediates and peripheral cis Golgi elements, but not in post‐Golgi compartments. Our results suggest that the low level of wild‐type CFTR in the Golgi region reflects a limiting step in selective recruitment by the ER export machinery, an event that is largely deficient in ΔF508. We raise the possibility that novel modes of selective anterograde and retrograde traffic between the ER and the Golgi may serve to regulate CFTR function in the early secretory compartments.
Trafficking and Folding Defects in Hereditary Spherocytosis Mutants of the Human Red Cell Anion Exchanger
Authors: Quilty Janne A. , Reithmeier Reinhart A.F.
Published: March 2003

Hereditary spherocytosis (HS) is a common inherited hemolytic anemia caused by mutations in erythrocyte proteins including the anion exchanger, AE1 (band 3). This study examined seven missense mutations (L707P, R760Q, R760W, R808C, H834P, T837M, and R870W) located in the membrane domain of the human AE1 that are associated with this disease. The HS mutants, constructed in full‐length AE1 cDNA, could be transiently expressed to similar levels in HEK 293 cells. Immunofluorescence, cell surface biotinylation, and pulse chase labeling showed that the HS mutants all exhibited defective cellular trafficking from the endoplasmic reticulum to the plasma membrane. Impaired binding to an inhibitor affinity matrix indicated that the mutant proteins had non‐native structures and may be misfolded. Further characterization of the HS R760Q mutant showed no change in its oligomeric structure or turnover (half‐life=15 h) compared to wild‐type AE1, suggesting the mutant was not aggregated or targeted for rapid degradation via the proteasome. Intracellular retention of HS mutant AE1 would lead to destruction of the protein during erythroid development and would account for the lack of HS mutant AE1 in the plasma membrane of the mature red cell.
Mitochondrial Inheritance in Budding Yeast
Authors: Boldogh Istvan R. , Yang Hyeong‐Cheol , Pon Liza A.
Published: March 2003

During the past decade significant advances were made toward understanding the mechanism of mitochondrial inheritance in the yeast Saccharomyces cerevisiae. A combination of genetics, cell‐free assays and microscopy has led to the discovery of a great number of components. These fall into three major categories: cytoskeletal elements, mitochondrial membrane components and regulatory proteins. These proteins mediate activities, including movement of mitochondria from mother cells to buds, segregation of mitochondria and mitochondrial DNA, and equal distribution of the organelle between mother cells and buds during yeast cell division.
GLUT4 – At the Cross Roads Between Membrane Trafficking and Signal Transduction
Authors: Simpson Fiona , Whitehead Jonathan P. , James David E.
Published: March 2003

GLUT4 is a mammalian facilitative glucose transporter that is highly expressed in adipose tissue and striated muscle. In response to insulin, GLUT4 moves from intracellular storage areas to the plasma membrane, thus increasing cellular glucose uptake. While the verification of this ‘translocation hypothesis’ (Cushman SW, Wardzala LJ. J Biol Chem 1980;255: 4758–4762 and Suzuki K, Kono T. Proc Natl Acad Sci 1980;77: 2542–2545) has increased our understanding of insulin‐regulated glucose transport, a number of fundamental questions remain unanswered. Where is GLUT4 stored within the basal cell? How does GLUT4 move to the cell surface and what mechanism does insulin employ to accelerate this process? Ultimately we require a convergence of trafficking studies with research in signal transduction. However, despite more than 30 years of intensive research we have still not reached this point. The problem is complex, involving at least two separate signal transduction pathways which feed into what appears to be a very dynamic sorting process. Below we discuss some of these complexities and highlight new data that are bringing us closer to the resolution of these questions.
Disabled‐2 Colocalizes with the LDLR in Clathrin‐Coated Pits and Interacts with AP‐2
Authors: Morris Shelli M. , Cooper Jonathan A.
Published: March 2003

Disabled‐2 (Dab2) is a widely expressed relative of Disabled‐1, a neuron‐specific signal‐transduction protein that binds to and receives signals from members of the low‐density lipoprotein receptor (LDLR) family. Members of the LDLR family internalize through clathrin‐coated pits and vesicles to endosomes, from where they return to the cell surface through the secretory pathway. In this study, we show that the Dab2 phosphotyrosine‐binding domain binds peptides containing the sequence FXNPXY. This core sequence is found in the intracellular domains of LDLR family members and is important for receptor internalization. Dab2 transiently colocalizes with the LDLR in clathrin‐coated pits, but is absent from endosomes and lysosomes. Dab2 is alternatively spliced and its localization depends on a region of the protein that contains two DPF motifs that are present in the p96 Dab2 protein and absent in the p67 splice variant. This region is sufficient to confer Dab2 binding to the α‐adaptin subunit of the clathrin adaptor protein, AP‐2. Overexpression of p96 but not of p67 Dab2 disrupts the localization of AP‐2. These findings suggest that in addition to previously reported signal‐transduction functions, Dab2 could also act as an adaptor protein that may regulate protein trafficking.
Energetics of Clathrin Basket Assembly
Authors: Nossal Ralph
Published: March 2003

A minimal thermodynamic model is used to study the in vitro equilibrium assembly of reconstituted clathrin baskets. The model contains parameters accounting for i) the combined bending and flexing rigidities of triskelion legs and hubs, ii) the intrinsic curvature of an isolated triskelion, and iii) the free energy changes associated with interactions between legs of neighboring triskelions. Analytical expressions for basket size distributions are derived, and published size distribution data (Zaremba S, Keen JH. J Cell Biol 1983;97: 1339–1347) are then used to provide estimates for net total basket assembly energies. Results suggest that energies involved in adding triskelions to partially formed clathrin lattices are small (of the order of kBT), in accord with the notion that lattice remodeling during basket formation occurs as a result of thermodynamic fluctuations. In addition, analysis of data showing the effects of assembly proteins (APs) on basket size indicates that the binding of APs increases the intrinsic curvature of an elemental triskelial subunit, the stabilizing energy of leg interactions, and the effective leg/hub rigidity. Values of effective triskelial rigidity determined in this investigation are similar to those estimated by previous analysis of shape fluctuations of isolated triskelia.
Targeting of C‐Terminal (Tail)‐Anchored Proteins: Understanding how Cytoplasmic Activities are Anchored to Intracellular Membranes
Authors: Wattenberg Binks , Lithgow Trevor
Published: March 2003

A class of integral membrane proteins, referred to as ‘tail‐anchored proteins’, are inserted into phospholipid bilayers via a single segment of hydrophobic amino acids at the C‐terminus, thereby displaying a large functional domain in the cytosol. This membrane attachment strategy allows eukaryotic cells to position a wide range of cytoplasmic activities close to the surface of an intracellular membrane. Tail‐anchored proteins often, but not always, demonstrate a selective distribution to specific intracellular organelles. This membrane‐specific distribution is required for the large number of targeting proteins that are tail‐anchored, but may or may not be critical for the numerous tail‐anchored pro‐apoptotic and anti‐apoptotic proteins of the Bcl‐2 family. Recent work has begun to address the mechanism for targeting tail‐anchored proteins to their resident membranes, but questions remain. What targeting signals determine each protein's intracellular location? Are there receptors for these signals and, if so, how do they function? What steps are required to integrate tail‐anchored proteins into the phospholipid bilayers? In this Traffic Interchange, we summarise what is known about tail‐anchored proteins, and outline the areas that are currently under study.
Protein Export from the Nucleus
Authors: Ossareh‐Nazari Batool , Gwizdek Carole , Dargemont Catherine
Published: March 2003

The evolution of the nucleus imposed on eukaryotic cells the necessity to strictly control exchange of molecules between the nucleus and the remainder of the cell, not only to protect and correctly transmit genetic information, but also to coordinate nuclear and cytoplasmic functions. Studies over the past 10 years have provided major insights into the molecular mechanisms responsible for transport of molecules between the nucleus and the cytoplasm. In addition, regulation of the nucleocytoplasmic distribution of diverse cellular factors has emerged as one of the most efficient mechanism to adapt gene expression to the cell environment, for example by controlling the access of transcriptional regulators to their target genes. In this review, we focus on the molecular basis of protein nuclear export that relies on interactions between targeting sequences present on the cargoes, specific export receptors or exportins and nuclear pore proteins, with special emphasis on the role of the Ran GTPase and associated proteins in this process.
Visualization of Actin Dynamics During Macropinocytosis and Exocytosis
Authors: Lee Eunkyung , Knecht David A.
Published: March 2003

Macropinocytosis of newly formed resides and exocytosis of post‐lysosomes have been visualized using a green fluorescent protein probe that binds specifically to F‐actin filaments. F‐actin association with macropinocytosis begins as a V‐shaped infolding of the membrane. Vesicle enlargement occurs through an inward movement of the proximal point of the V as well as an outward protrusion at the tip of the V to form an elongated invagination. The protrusion eventually closes at its distal margin to become a vesicle and is moved centripetally while recovering its circular shape. The vesicle loses its actin coat within 1 min after internalization. One hour later, post‐lysosomal vesicles became weakly surrounded by actin while still cytoplasmic. Some of these vesicles moved to the plasma membrane, docked, and then expelled their contents. Slightly before the vesicle content began to disappear, an increase in F‐actin association with the vesicle was observed. This was followed by rapid contraction of the vesicle and then disappearance of the actin signal once the internal content was released. These results show that dynamic changes in actin filament association with the vesicle membrane accompany both endocytosis and exocytosis.
Metazoan Motor Models: Kinesin Superfamily inC. elegans
Authors: Siddiqui Shahid S.
Published: March 2003

In eukaryotic cells members of the kinesin family mediate intracellular transport by carrying cellular cargo on microtubule tracks. The nematodeCaenorhabditis elegansgenome encodes 21 members of the kinesin family, which show significant homology to their mammalian orthologs. Based on motor domain sequence homology and placement of the motor domain in the protein, theC. eleganskinesins have been placed in eight distinct groups; members of which participate in embryonic development, protein transport, synaptic membrane vesicles movement and in the axonal growth. Among 21 kinesins, at least 11 play a central role in spindle movement and chromosomal segregation. Understanding the function ofC. eleganskinesins and related proteins may help navigate through the intricacies of intracellular traffic in a simple animal.
Automated Recognition of Intracellular Organelles in Confocal Microscope Images
Authors: Danckaert A. , Gonzalez‐Couto E. , Bollondi L. , Thompson N. , Hayes B.
Published: March 2003

Recognition of the localisation of intracellular proteins is essential to the understanding of their function. It is usually made through knowledge of and comparison to the distribution of well‐characterised intracellular organelles by experts in cell biology. We have automated this process in order to achieve a more objective and quantitative assessment of the protein distribution within the cell, which can be employed by the less experienced cell biologist and may be utilised as a training program for inexperienced users, or as a high throughput localisation program for novel genes in functional analysis. Here we describe the development and testing of a classification system based on a modular neural network trained with sets of confocal sections through cell lines fluorescently stained for markers of key intracellular structures. The system functioned well in spite of the variability in pattern that occurs between individual cells and performed with 97% accuracy, which gives us confidence in the method and in its future development. It is envisaged that this program will aid the design of further experiments utilising colocalisation with known organelle marker proteins, in order to confirm putative trafficking pathways and protein–protein interactions of the protein of interest.
RhoGDI‐3 Regulates RhoG and Targets This Protein to the Golgi Complex Through its Unique N‐Terminal Domain
Authors: Brunet Nicolas , Morin Annie , Olofsson Birgitta
Published: March 2003

Guanine nucleotide dissociation inhibitors (GDIs) regulate both GDP/GTP and membrane association/dissociation cycles of Rho/Rac and Rab proteins.RhoGDI‐3 is distinguishable from other rhoGDI proteins by its partial association with a detergent‐resistant subcellular fraction. Here, we investigate the activity of this unusual rhoGDI using confocal laser scanning microscopy, immuno‐isolation, and rhoGDI‐3 mutants. We establish that the noncytosolic fraction of rhoGDI‐3 is associated with the Golgi apparatus. The domain involved in this association is the unique N‐terminal segment of rhoGDI‐3 predicted to form an amphipathic α helix. This peptide is indispensable for Golgi association of rhoGDI‐3 and sufficient to address a green fluorescent protein to the Golgi apparatus. Site‐directed mutations, decreasing the hydrophobic surface of the helix, localize rhoGDI‐3 into the cytoplasm. We establish that rhoGDI‐3 is able to inhibit activation of the RhoG protein and to target this protein to the Golgi apparatus. Furthermore, we demonstrate the importance of the rhoGDI‐3 N‐terminal segment for both Golgi targeting and stability of the cytoplasmic RhoG/rhoGDI‐3 complex. RhoGDI‐3 is the first example of a GDI directly involved in the delivery of a Rho protein to a specific subcellular compartment.
The β‐Amyloid Precursor Protein (APP) and Alzheimer's Disease: Does the Tail Wag the Dog?
Authors: Koo Edward H.
Published: March 2003

The β‐amyloid precursor protein has been the focus of much attention from the Alzheimer's disease community for the past decade and a half. The β‐amyloid precursor protein holds a pivotal position in Alzheimer's disease research because it is the precursor to the amyloid β‐protein which many believe plays a central role in Alzheimer's disease pathogenesis. It was also the first gene in which mutations associated with inherited Alzheimer's disease were found. Although the molecular details of the generation of amyloid β‐protein from β‐amyloid precursor protein are being unraveled, the actual physiological functions of β‐amyloid precursor protein are far from clear. This situation is changing as accumulating new evidence suggests that the C‐terminal cytosolic tail of β‐amyloid precursor protein may have multiple biological activities, ranging from axonal transport to nuclear signaling. This article reviews the current state of knowledge about the biological functions of β‐amyloid precursor protein.
Secretory Pathway Quality Control Operating in Golgi, Plasmalemmal, and Endosomal Systems
Authors: Arvan Peter , Zhao Xiang , Ramos‐Castaneda Jose , Chang Amy
Published: March 2003

Exportable proteins that have significant defects in nascent polypeptide folding or subunit assembly are frequently retained in the endoplasmic reticulum and subject to endoplasmic reticulum‐associated degradation by the ubiquitin‐proteasome system. In addition to this, however, there is growing evidence for post‐endoplasmic reticulum quality control mechanisms in which mutant or non‐native exportable proteins may undergo anterograde transport to the Golgi complex and post‐Golgi compartments before intracellular disposal. In some instances, these proteins may undergo retrograde transport back to the endoplasmic reticulum with re‐targeting to the endoplasmic reticulum‐associated degradation pathway; in other typical cases, they are targeted into the endosomal system for degradation by vacuolar/lysosomal proteases. Such quality control targeting is likely to involve recognition of features more commonly expressed in mutant proteins, but may also be expressed by wild‐type proteins, especially in cells with perturbation of local environments that are essential for normal protein trafficking and stability in the secretory pathway and at the cell surface.
Traffic Jams II: An Update of Diseases of Intracellular Transport
Authors: Aridor Meir , Hannan Lisa A.
Published: March 2003

As more details emerge on the mechanisms that mediate and control intracellular transport, the molecular basis for variety of human diseases has been revealed. In turn, disease pathology and physiology shed light on the intricate controls that regulate intracellular transport to assure proper cellular and tissue function and homeostasis. We previously listed a number of diseases that are the result of defects in intracellular transport, or cause defects in intracellular transport. (Aridor M, Hannan LA. Traffic Jam: A compendium of human diseases that affect intracellular transport processes. Traffic 2000; 1: 836–851). This Toolbox updates the previous list to include additional disorders that were recently identified to be related to intracellular trafficking. In the time since we have published our first list there have been significant advances in understanding of the molecular basis of these defects. Such advances will pave the way to future effective therapeutics.
Myosin VI, an Actin Motor for Membrane Traffic and Cell Migration
Authors: Buss Folma , Luzio J. Paul , Kendrick‐Jones John
Published: March 2003

The actin cytoskeleton and associated myosin motor proteins are essential for the transport and steady‐state localization of vesicles and organelles and for the dynamic remodeling of the plasma membrane as well as for the maintenance of differentiated cell‐surface structures. Myosin VI may be expected to have unique cellular functions, because it moves, unlike almost all other myosins, towards the minus end of actin filaments. Localization and functional studies indicate that myosin VI plays a role in a variety of different intracellular processes, such as endocytosis and secretion as well as cell migration. These diverse functions of myosin VI are mediated by interaction with a range of different binding partners.
A New Yeast Endosomal SNARE Related to Mammalian Syntaxin 8
Authors: Lewis Michael J. , Pelham Hugh R. B.
Published: March 2003

We report the identification of a yeast SNARE that has escaped notice because of an apparent error in the genome sequence and because it is functionally redundant. It is encoded by an extended version of ORF YAL014c, and since its SNARE motif is related to mammalian syntaxin 8 we term the gene SYN8. Syn8p is in endosomes. Co‐precipitation indicates a set of complexes containing Pep12p, Vti1p, either Syn8p or Tlg1p and either Snc1p or Ykt6p. Analysis of growth and trafficking defects demonstrates that in the absence of Tlg1p, Syn8p is required for Pep12p function. Conversely, when Tlg1p is present, Syn8p can be removed without loss of Pep12p function, or induction of any other obvious trafficking defect. Syn8p thus appears to be a functional homolog of mammalian syntaxin 8, but Tlg1p can, amongst other roles, provide an equivalent function.
Prevalence and classification of HIV‐associated oral lesions
Authors: Patton LL , Phelan JA , Ramos‐Gomez FJ , Nittayananta W , Shiboski CH , Mbuguye TL
Published: March 2003

OBJECTIVES: An International Workshop addressed the prevalence and classification of HIV/AIDS associated oral lesions.

DESIGN: Five questions provided the framework for discussion and literature review. What is the prevalence of oral lesions in children and adults? Should the accepted classification of HIV‐related oral lesions be modified in the light of recent findings? Why is there a gender difference in the prevalence of oral lesions in developed and developing countries? Are there unusual lesions present in developing countries? Is there any association between modes of transmission and the prevalence of oral lesions?

RESULTS: Workshop discussion emphasized the urgent need for assistance in the development of expertise to obtain accurate global prevalence data for HIV‐associated oral lesions. Oral candidiasis has been consistently reported as the most prevalent HIV‐associated oral lesion in all ages. Penicilliosis marneffei, a newly described fungal infection, has emerged in South‐east Asia. Oral hairy leukoplakia and Kaposi's sarcoma appear to be associated with male gender and male‐to‐male HIV transmission risk behaviours. These lesions occur only rarely in children.

CONCLUSIONS: Additional prevalence data are needed from developing countries prior to substantially altering the 1993 ECC/WHO Classification of oral lesions associated with adult HIV infection. The workshop confirmed current oral disease diagnostic criteria.
Regulatory mechanisms of osteoblast and osteoclast differentiation
Authors: Katagiri T , Takahashi N
Published: March 2003

Bone is continuously destroyed and reformed to maintain constant bone volume and calcium homeostasis in vertebrates throughout their lives. Osteoblasts and osteoclasts are specialized cells responsible for bone formation and resorption, respectively. Recent developments in bone cell biology have greatly changed our conceptions of the regulatory mechanisms of the differentiation of osteoblasts and osteoclasts. Bone morphogenetic proteins (BMPs) play critical roles in osteoblast differentiation. The discovery of Smad‐mediated signals revealed the precise functions of BMPs in osteoblast differentiation. Transcription factors, Runx2 and Osterix, are found to be essential molecules for inducing osteoblast differentiation, as indicated by the fact that both Runx2‐null mice and Osterix‐null mice have neither bone tissue nor osteoblasts. Smad transcriptional factors are shown to interact with other transcription regulators, including Runx2. Also, the recent discovery of receptor activator of NF‐κB ligand (RANKL)–RANK interaction confirms the well‐known hypothesis that osteoblasts play an essential role in osteoclast differentiation. Osteoblasts express RANKL as a membrane‐associated factor. Osteoclast precursors that express RANK, a receptor for RANKL, recognize RANKL through the cell–cell interaction and differentiate into osteoclasts. Recent studies have shown that lipopolysaccharide and inflammatory cytokines such as tumor necrosis factor receptor‐α and interleukin 1 directly regulate osteoclast differentiation and function through a mechanism independent of the RANKL–RANK interaction. Transforming growth factor‐β super family members and interferon‐γ are also shown to be important regulators in osteoclastogenesis. These findings have opened new areas for exploring the molecular mechanisms of osteoblast and osteoclast differentiation.
Saliva and gastrointestinal functions of taste, mastication, swallowing and digestion
Authors: Pedersen AM , Bardow A , Jensen S Beier , Nauntofte B
Published: March 2003

Saliva has multiple essential functions in relation to the digestive process taking place in the upper parts of the gastrointestinal (GI) tract. This paper reviews the role of human saliva and its compositional elements in relation to the GI functions of taste, mastication, bolus formation, enzymatic digestion, and swallowing. The indirect function of saliva in the digestive process that includes maintenance of an intact dentition and mucosa is also reviewed. Finally, pathophysiological considerations of salivary dysfunction in relation to some GI functions are considered.
Salivary gland tumours
Authors: Speight PM , Barrett AW
Published: March 2003

Salivary gland tumours are a relatively rare and morphologically diverse group of lesions. Although most clinicians and pathologists will have encountered the more common benign neoplasms, few have experience of the full range of salivary cancers, which are best managed in specialist centres. This review considers some current areas of difficulty and controversy in the diagnosis and management of these neoplasms. The classification of these lesions is complex, encompassing nearly 40 different entities, but precise classification and terminology is essential for an accurate diagnosis and for the allocation of tumours to prognostic groups. For many salivary tumours diagnosis is straightforward but the wide range of morphological diversity between and within tumour types means that a diagnosis may not be possible on small incisional biopsies and careful consideration of the clinical and pathological features together is essential. Although tumour grading is important and helpful, it is not an independent prognostic indicator and must be considered in the context of stage. Large malignancies tend to have a poor prognosis regardless of grade and even high‐grade neoplasms may do well when they are small. A helpful guide to management of salivary cancers is the ‘4 cm rule’.
Segmental odontomaxillary dysplasia: clinical, radiological and histological aspects of four cases
Authors: Becktor KB , Reibel J , Vedel B , Kjær I
Published: March 2003

Segmental odontomaxillary dysplasia (SOD) is a rare developmental disorder of the maxilla, primarily involving the posterior part of the maxilla. Clinically, the disorder is often diagnosed in early childhood due to a unilateral buccolingual expansion of the posterior alveolar process, gingival enlargement, absence of one or both premolars in the affected region, delayed eruption of the adjacent teeth and malformations of the primary molars. In this report, four patients with SOD are described. The findings were similar to earlier reports, but for the first time an ipsilateral rough erythema on the skin in two of the subjects is reported.
IGF‐1 and insulin receptor expression in the minor salivary gland tissues of Sjögren's syndrome and mucoceles – immunohistochemical study
Authors: Katz J , Stavropoulos F , Cohen D , Robledo J , Stewart C , Heft M
Published: March 2003

OBJECTIVE: To investigate the expression of IGF‐1 receptors and insulin receptors on the minor salivary gland (MSG) tissues of patients diagnosed with Sjögren's syndrome (SS) and normal salivary gland tissue surrounding mucoceles.

SUBJECTS AND METHODS: Five MSG tissue sections from SS and seven from mucocele patients were stained immunohistochemically using antibody to IGF‐1 receptor and insulin receptor in a horse radish peroxidase and DAB system.

RESULTS: The expression of the insulin receptor was increased in the SS sections compared with controls, while the insulin‐like growth factor‐1 receptor was more intensely expressed in the controls.

CONCLUSION: The presence of differential expression of receptors for IGF and insulin might suggest a possible role of these growth factors in the pathogenesis of SS.
The making of a nation‐wide campaign fighting the nursing caries
Authors: Van Der Sanden‐Stoelinga M. S. E. , Koelen M. A. , Hielkema‐de Meij J. E.
Published: March 2003

Abstract:  Although, in the Netherlands, the fight against tooth decay has been successful over the past decades, in 1994, the incidence of nursing caries made the Ivory Cross*, the Dutch National Association for the Promotion of Oral Hygiene, decide to develop and implement a campaign to address the phenomenon. The campaign is based on a two‐step approach: a community strategy that exposes both the intermediaries and the target group to the message. It mainly focussed on intermediaries (step 1) such as child health clinic teams and care attendants, aiming to motivate and enable them to address the topic in their communication with parents of children aged 0–4 years (step 2). The development of this campaign lasted for about 1.5 years and will be described along the lines of the OPUS model: Orientation, Planning, execUtion and cloSure. The campaign was continuously assessed by means of research consisting of a pretest of materials, and a process and outcome evaluation. The research results gave the organisers a lot of information to monitor the campaign and useful insights for future activities.
The membrane‐tethering protein p115 interacts with GBF1, an ARF guanine‐nucleotide‐exchange factor
Authors: García‐Mata Rafael , Sztul Elizabeth
Published: March 2003

The membrane‐transport factor p115 interacts with diverse components of the membrane‐transport machinery. It binds two Golgi matrix proteins, a Rab GTPase, and various members of the soluble N ‐ethylmaleimide‐sensitive factor attachment protein receptor (SNARE) family. Here, we describe a novel interaction between p115 and Golgi‐specific brefeldin‐A‐resistant factor 1 (GBF1), a guanine‐nucleotide exchange factor for ADP ribosylation factor (ARF). GBF1 was identified in a yeast two‐hybrid screen, using full‐length p115 as bait. The interaction was confirmed biochemically, using in vitro and in vivo assays. The interacting domains were mapped to the proline‐rich region of GBF1 and the head region of p115. These proteins colocalize extensively in the Golgi and in peripheral vesicular tubular clusters. Mutagenesis analysis indicates that the interaction is not required for targeting GBF1 or p115 to membranes. Expression of the p115‐binding (pro‐rich) region of GBF1 leads to Golgi disruption, indicating that the interaction between p115 and GBF1 is functionally relevant.
Occurrence of a putative ancient‐like isomerase involved in histidine and tryptophan biosynthesis
Authors: Barona‐Gómez Francisco , Hodgson David A
Published: March 2003

We report the occurrence of an isomerase with a putative (βα)8‐barrel structure involved in both histidine and trypto‐phan biosynthesis in Streptomyces coelicolor A3(2) and Mycobacterium tuberculosis HR37Rv. Deletion of a hisA homologue (SCO2050) putatively encoding N ′‐[(5′‐phosphoribosyl)‐formimino]‐5 amino‐imidazole‐4‐carboxamide ribonucleotide isomerase from the chromosome of S. coelicolor A3(2) generated a double auxotrophic mutant for histidine and tryptophan. The bifunctional gene SCO2050 and its orthologue Rv1603 from M. tuberculosis complemented both hisA and trpF mutants of Escherichia coli. Expression of the E. coli trpF gene in the S. coelicolor mutant only complemented the tryptophan auxo‐trophy, and the hisA gene only complemented the histidine auxotrophy. The discovery of this enzyme, which has a broad‐substrate specificity, has implications for the evolution of metabolic pathways and may prove to be important for understanding the evolution of the (βα)8‐barrels.
Regulation of tensin-promoted cell migration by its focal adhesion binding and Src homology domain 2
Authors: CHEN Huaiyang , LO S. Hao
Published: March 2003

Tensin1 is an actin- and phosphotyrosine-binding protein that localizes to focal adhesions. Recently, we have shown that both tensin1 and a new family member, tensin2, promote cell migration [Chen, Duncan, Bozorgchami and Lo (2002) Proc. Natl. Acad. Sci. U.S.A. 99, 733—738]. Since localization of proteins to particular intracellular compartments often regulates their functions, and Src homology domain 2 may mediate signals related to cell migration, we hypothesize that tensin-mediated cell migration is regulated by the focal adhesion localization and the Src homology domain 2 of tensin. To test this hypothesis, we have analysed the effects of a series of tensin1 mutants on cell migration. Our results have shown that (1) tensin1 contains two focal adhesion-binding sites, (2) the wild-type tensin1 significantly promotes cell migration, (3) mutants with one focal adhesion-binding site do not promote cell migration, (4) the non-focal adhesion localized mutant suppresses cell migration and (5) the mutant that is not able to bind to phosphotyrosine-containing proteins has no effect on cell migration. These results have indicated that focal adhesion localization of tensin1 and the phosphotyrosine-binding activity are two critical factors in regulating tensin-mediated cell migration.
Phosphatidylethanolamine N-methyltransferase (PEMT) knockout mice have hepatic steatosis and abnormal hepatic choline metabolite concentrations despite ingesting a recommended dietary intake of choline
Authors: ZHU Xiaonan , SONG Jiannan , MAR Mei-Heng , EDWARDS Lloyd J. , ZEISEL Steven H.
Published: March 2003

Choline is an essential nutrient for humans and is derived from the diet as well as from de novo synthesis involving methylation of phosphatidylethanolamine catalysed by the enzyme phosphatidylethanolamine N-methyltransferase (PEMT). This is the only known pathway that produces new choline molecules. We used mice with a disrupted Pemt-2 gene (which encodes PEMT; Pemt-/-) that have previously been shown to possess no hepatic PEMT enzyme. Male, female and pregnant Pemt-/- and wild-type mice (n = 5—6 per diet group) were fed diets of different choline content (deficient, control, and supplemented). Livers were collected and analysed for choline metabolites, steatosis, and apoptotic [terminal deoxynucleotidyl transferase-mediated dUTP—biotin nick end-labelling (TUNEL)] positive cells. We found that, in livers of Pemt-/- mice fed any of the diets, there was hepatic steatosis and significantly higher occurrence of TUNEL positive cells compared with wild-type controls. In male, female and pregnant mice, liver phosphatidylcholine concentrations were significantly decreased in Pemt-/- choline deficient and in Pemt-/- choline control groups but returned to normal in Pemt-/- choline supplemented groups. Phosphocholine concentrations in liver were significantly diminished in knockout mice even when choline was supplemented to above dietary requirements. These results show that PEMT normally supplies a significant portion of the daily choline requirement in the mouse and, when this pathway is knocked out, mice are unable to attain normal concentrations of all choline metabolites even with a supplemental source of dietary choline.