bluuebunny/crossref_metadata_2025 huggingface dataset:
Exposure to short days, but not short‐term melatonin, enhances humoral immunity of male Syrian hamsters (Mesocricetus auratus)
Authors: Drazen Deborah L. , Jasnow Aaron M. , Nelson Randy J. , Demas Gregory E.
Published: March 2003

Abstract: Many non‐tropical rodent species rely on photoperiod as the primary cue to co‐ordinate seasonally appropriate changes in physiology and behavior. Among these seasonal changes, several rodent species (e.g. deer mice, prairie voles, Siberian hamsters) adjust immune function in response to changes in ambient day lengths. The goals of the present study were to examine the effects of photoperiod on immune function of Syrian hamsters (Mesocricetus auratus), and to determine the role of melatonin in mediating photoperiodic changes in immunity. In Experiment 1, male Syrian hamsters were housed in long (LD 14:10) or short days (LD 10:14) for 10 wk. In Experiment 2, hamsters were housed in long days and half of the animals were given 10 consecutive days of i.p. melatonin injections (15 μg) in the early evening, while the remaining animals received injections of the vehicle alone. After the respective experimental manipulations, animals were injected with the antigen, keyhole limpet hemocyanin (KLH), blood samples were obtained and anti‐KLH IgG antibody production was assessed. In Experiment 1, short‐day hamsters underwent gonadal regression and reduced serum testosterone as well as displayed increased humoral immune function compared with long‐day animals. In Experiment 2, short‐term melatonin treatment did not affect gonadal mass, testosterone or humoral immune function. These results confirm previous findings of photoperiodic changes in immunity in rodents and suggest that changes in humoral immunity are not due to short‐term changes in melatonin.
Myocardial ischemia–reperfusion in rats: reduction of infarct size by either supplemental physiological or pharmacological doses of melatonin
Authors: Sahna Engin , Acet Ahmet , Kaya Ozer M. , Olmez Ercument
Published: March 2003

Abstract: Myocardial ischemia–reperfusion (I/R) represents a clinically relevant problem associated with thrombolysis, angioplasty and coronary bypass surgery. I/R injury is believed to be a consequence of free radical generation in the heart especially during the period of reperfusion. The pineal secretory product, melatonin, is known to be a potent free radical scavenger and pharmacological concentrations have been shown to reduce the I/R‐induced cardiac damage in isolated rat hearts. However, the physiological role of melatonin in the prevention of this damage is unknown. Rats were pinealectomized or sham‐operated (control) 2 months before the I/R studies. To produce cardiac damage, the left main coronary artery was occluded for 30 min, followed by 120 min reperfusion, in anesthetized rats. Infarct size, expressed as the percentage of the risk zone, was found significantly higher in pinealectomized rats (49±3.4%) than in the control group (34±3.6%). Melatonin administration (4 mg/kg, either before ischemia or reperfusion) to pinealectomized rats significantly reduced the infarct size values and returned them to the control values. On the other hand, melatonin administration (4 mg/kg) to sham‐operated rats failed to attenuate significantly the I/R‐induced infarct size. These results suggest that physiological melatonin concentrations are important in reducing the I/R‐induced myocyte damage, while pharmacological concentrations of melatonin did not add to the beneficial effect. As melatonin levels have been reported to decrease with age, melatonin replacement therapy may attenuate I/R‐induced myocardial injury, especially in older patients.
Regulation of gene expression by melatonin: a microarray survey of the rat retina
Authors: Wiechmann Allan F.
Published: March 2003

Abstract: The pineal secretory product melatonin is synthesized by pinealocytes and retinal photoreceptors on a cyclic rhythm, with highest levels occurring at night. Our previous work has demonstrated that melatonin treatment increases the sensitivity of the rat retina to light‐induced photoreceptor cell death. This raises the possibility that inappropriate exposure of photoreceptors to melatonin may result in visual impairment, caused by a loss of retinal photoreceptors. We hypothesize that retinal genes whose expression levels are altered in response to melatonin may be involved in processes that contribute to light‐induced photoreceptor cell death. To identify retinal genes that are up‐ or down‐regulated in response to melatonin receptor binding, rats were treated with or without melatonin, and the RNA from the neural retinas and retinal pigment epithelium (RPE) were analyzed for differential gene expression by hybridization of labeled cRNA probes to an Affymetrix rat genome microarray set. GeneChip algorithms were applied to measured hybridization intensities of compared samples and showed that in the neural retina, six genes were up‐regulated, and eight were down‐regulated. In the RPE, 15 genes were up‐regulated, and two genes were down‐regulated. The protein products of these specific genes are potentially involved in the molecular mechanism of melatonin action in the retina, and may play a role in the effect of melatonin on light‐induced photoreceptor cell death. Identification of these candidate genes and their response to melatonin administration may provide a foundation for further studies on gene regulation by melatonin, the function of melatonin in the retina, and the role of circadian signaling in inherited and environmentally induced photoreceptor degenerations.
Melatonin induces tyrosine hydroxylase mRNA expression in the ventral mesencephalon but not in the hypothalamus
Authors: Venero José L , Absi El‐Hadi , Cano Josefina , Machado Alberto
Published: March 2003

We have evaluated the effect of chronic administration of melatonin in terms of mRNA expression for tyrosine hydroxylase (TH), the rate‐limiting enzyme in catecholamine biosynthesis, and in the terms of dopamine (DA) transporter (DAT) by means of in situ hybridization. Experimental rats received daily late afternoon injections of 1.5 mg/kg melatonin for 30 days and analysis were performed in the ventral mesencephalon including the substantia nigra (SN) and ventral tegmental area (VTA), and hypothalamus. In the ventral mesencephalon, melatonin treatment significantly induced TH mRNA levels in individual dopaminergic neurons in SN and VTA. In contrast, DAT mRNA levels remained at control levels. Striatal synaptosomal DA uptake was not modified by melatonin treatment as compared with controls. Analysis of glutamic acid decarboxylase (GAD) mRNA in SN, the biosynthetic enzyme for GABAergic neurons, revealed no effect of melatonin treatment on mRNA levels for this marker. In the hypothalamus, we performed mRNA quantitation for TH in arcuate nucleus (Arc) and supraoptic nucleus (SO). Melatonin treatment failed to alter mRNA levels in either area. We detected weak but significant mRNA levels for DAT in Arc, SO, zona incerta (ZI) and periventricular hypothalamic nucleus (Pe). However, because of the low levels of mRNA in hypothalamic areas we were unable to perform a reliable measurement of DAT mRNA levels in response to melatonin treatment. We conclude that melatonin administration, that combines antioxidant capacity and a tissue‐specific TH inducing effect, may be useful as a pharmacological agent to protect dopaminergic neurons from degeneration.
Melatonin attenuates the neuronal NADPH‐d/NOS expression in the nodose ganglion of acute hypoxic rats
Authors: Chang Hung‐Ming , Ling Eng‐Ang , Chen Chau‐Fong , Lue June‐Horng , Wen Chen‐Yuan , Shieh Jeng‐Yung
Published: March 2003

Excessive production of nitric oxide (NO) may play a detrimental role in the process of hypoxia‐related neuropathology. This study explored whether treatment with melatonin would attenuate the neuropathological changes in the vagal ganglia following a severe hypoxic insult. Thirty minutes prior to hypoxia treatment, young adult rats were pre‐treated with melatonin at 5, 25 or 100 mg/kg injected intraperitoneally. Hypoxia was achieved by subjecting the rats to a barometric pressure of 0.2 atm (PO2=43 Torr) for 4 hr in an altitude chamber. Nicotinamine adenine dinucleotide phosphate‐diaphorase (NADPH‐d) histochemistry combined with the neuronal nitric oxide synthase (nNOS) immunohistochemistry were used to detect the NADPH‐d/nNOS reactivity in the nodose ganglion (NG) at various time points following the hypoxic exposure. In normal untreated rats, about 43% of the neurons in the NG displayed NADPH‐d/nNOS reactivity. Following hypoxic exposure, both the percentage and the staining intensity of NADPH‐d/nNOS positive neurons in the NG were markedly increased, but these were reduced in longer surviving animals. Quantitative analysis of cell counts revealed that about 17% of the neurons died at 14 days after hypoxia treatment. However, in hypoxic rats given different doses of melatonin pre‐treatment, neuronal death as well as the frequency and staining intensity of NADPH‐d/nNOS reactivity of the nodose neurons were significantly decreased. The effect of melatonin on neuronal survival and NADPH‐d/nNOS expression was dose‐dependent. It is therefore suggested that melatonin exerts a neuroprotective effect and may serve as a potential therapeutic strategy for prevention and/or reducing the susceptibility of nodose neurons to NO‐mediated hypoxic neuropathy.
2[125I]Iodomelatonin binding sites in guinea pig platelets
Authors: Yau Mabel Y. C. , Pang Celia S. , Kravtsov Gennadi , Pang Shiu F. , Shiu Stephen Y. W.
Published: March 2003

Using 2[125I]iodomelatonin as the radioligand, we characterized 2[125I]iodomelatonin binding sites in guinea pig platelet membrane preparations. Saturation radioreceptor studies indicated that these 2[125I]iodomelatonin binding sites were of picomolar affinity and femtomolar density. The dissociation constant (Kd) and maximum number of receptor sites (Bmax) were 42.5 ± 1.79 pM and 11.8 ± 0.8 fmol/mg protein (n=6), respectively. 2[125I]Iodomelatonin competition studies with indoles or drugs indicate the following rank order of potency: 2‐iodomelatonin >melatonin ≥ 6‐chloromelatonin > 6‐hydroxymelatonin > N‐acetylserotonin >  5‐methoxytryptophol, whereas serotonin and its analogs had less than 20% inhibition at 0.1 mM. Guanosine 5′‐O‐(3‐thiotriphosphate) significantly increased the Kd by twofold suggesting that these binding sites are coupled to the guanine nucleotide binding proteins. Immunoblotting studies using anti‐MT1 IgG demonstrated one peptide blockable band with an apparent molecular mass of 37 kDa. Melatonin had no effect on prostacyclin or forskolin‐stimulated intracellular 3′,5′‐cyclic adenosine monophosphate accumulation. A diurnal variation in binding density, which was abolished after the animals were adapted to constant light conditions, was observed. Age related studies demonstrated that Bmax increased as the animal matured. Physiological melatonin concentrations potentiated whereas those at pharmacological levels inhibited adenosine diphosphate‐ or arachidonic acid‐stimulated platelet aggregation. Our study demonstrated G‐protein coupled, saturable, reversible and highly specific picomolar affinity 2[125I]iodomelatonin binding sites in guinea pig platelets. Pharmocological and physiological data indicate that they may be different from the nanomolar [3H]melatonin binding sites in human platelets previously reported.
Seasonal changes in melatonin concentrations in female Iberian red deer (Cervus elaphus hispanicus)
Authors: García Andrés , Landete‐Castillejos Tomás , Zarazaga Luis , Garde Julián , Gallego Laureano
Published: March 2003

Abstract: In deer, most of the earlier investigations on pineal function examined the effects of artificial photoperiods or the administration of melatonin to manipulate reproduction. However, endogenous melatonin rhythms have not been studied in red deer. Thus, we monitored seasonal changes in plasma melatonin concentrations in 16 adult female Iberian red deer living in outdoor enclosures. Blood was sampled on the day of each seasonal change every 3–4 hr overnight and 1 hr before and after sunset and sunrise. In addition, in six of the previous hinds, blood sampling during the hour prior and after sunset and sunrise was collected every 20 min. Significant differences were found both in amplitude and duration of the nocturnal plasma melatonin profiles in the four seasonal changes (P<0.01). The nocturnal mean level of melatonin, the duration of nocturnal secretion levels and maximal concentrations were significantly higher at the winter solstice than in summer solstice or equinoxes (P<0.05). Moreover, the mean overnight concentrations were significantly higher at the spring equinox and winter solstice than during the summer solstice and autumn equinox (P<0.05). A pronounced elevation from low levels was recorded 1 hr after sunset, remained elevated during the hours of darkness and declined to low levels 1 hr after dawn. Concentrations close to sunrise were higher than those near sunset at all changes of season (P<0.05). These results show for the first time in red deer that the pineal gland of the adult female is highly responsive to both daily and seasonal changes in natural environmental illumination, although overnight levels lasted longer than the photoperiodic night is all cases, particularly at the winter solstice.
Melatonin modulates the action of near infrared radiation on cell adhesion
Authors: Karu Tiina I. , Pyatibrat Ludmila V. , Ryabykh Tatyana P.
Published: March 2003

Abstract: The adhesion of human cervical cancer (HeLa) cells to a glass matrix is evaluated following their irradiation in a suspension with a pulsed near‐infrared (IR) light‐emitting diode (wavelength 820 nm, pulse repetition frequency 10 Hz, irradiation dose 16–120 J/m2) when melatonin (4 × 10−11 to 4 × 10−5 m) is added to cell suspension immediately before or after the irradiation. Also, the dependence of visible‐to‐near‐IR radiation (600–840 nm, 52 J/m2) on cell adhesion (action spectrum) is recorded in absence and presence of melatonin (4 × 10−6 m). It is found that melatonin in pharmacological concentrations (but not in physiological range) inhibited cell adherence. Irradiation of cells before or after melatonin treatment normalizes cell adhesion to control level. Melatonin in pharmacological concentrations eliminates stimulation of cell attachment induced by irradiation. Pre‐treatment (but not post‐treatment) with melatonin in the physiological concentration eliminates cell adhesion stimulation induced by irradiation. Melatonin modifies the light action spectrum significantly in near IR region (760–840 nm only). Thus, the peak at 820–830 nm characteristic for the light action spectrum is fully reduced.
Melatonin: a hormone, a tissue factor, an autocoid, a paracoid, and an antioxidant vitamin
Authors: Tan Dun‐Xian , Manchester Lucien C. , Hardeland Rüdiger , Lopez‐Burillo Silvia , Mayo Juan C. , Sainz Rosa M. , Reiter Russel J.
Published: March 2003

Abstract: Melatonin, a derivative of an essential amino acid, tryptophan, was first identified in bovine pineal tissue and subsequently it has been portrayed exclusively as a hormone. Recently accumulated evidence has challenged this concept. Melatonin is present in the earliest life forms and is found in all organisms including bacteria, algae, fungi, plants, insects, and vertebrates including humans. Several characteristics of melatonin distinguish it from a classic hormone such as its direct, non‐receptor‐mediated free radical scavenging activity. As melatonin is also ingested in foodstuffs such as vegetables, fruits, rice, wheat and herbal medicines, from the nutritional point of view, melatonin can also be classified as a vitamin. It seems likely that melatonin initially evolved as an antioxidant, becoming a vitamin in the food chain, and in multicellular organisms, where it is produced, it has acquired autocoid, paracoid and hormonal properties.
Different responsiveness of central nervous system tissues to oxidative conditions and to the antioxidant effect of melatonin
Authors: Kaptanoglu Erkan , Palaoglu Selcuk , Demirpence Ediz , Akbıyık Filiz , Solaroglu Ihsan , Kılınc Asuman
Published: March 2003

Abstract: Melatonin, a product of the pineal gland, is an effective free‐radical scavenger both in vitro and in vivo. Free‐radical‐mediated lipid peroxidation has been increasingly considered as an important factor in post‐traumatic neuronal degeneration. The aim of the present study was (i) to examine the responses of different regions of central nervous system (CNS) to free‐radical generation induced in vitro and (ii) to test the efficacy of melatonin in reducing oxidative damage in different regions of the CNS. Rat brain, total spinal cord, spinal cord white matter and optic nerves were dissected with the rats under general anesthesia and immediately frozen at −20°C. Thiobarbituric acid reactive substances were measured as an index of lipid peroxidation. Peroxidation was induced with ferrous iron (0.02 mm), ascorbate (1 mm), and hydrogen peroxide (H2O2) (0.5 mm). All tissue samples showed increased lipid peroxidation levels after treatment with free‐radical generating agents. The highest amount of damage was observed in the presence of ferrous iron, ascorbate, and H2O2. Melatonin showed antioxidant effects in the brain, total spinal cord, optic nerve, and spinal cord white matter. The results show that melatonin has differential protective effects on CNS tissues in vitro and the most potent effect is observed in the spinal cord white matter.
Effects on the foetus of exercise in pregnancy
Authors: Riemann M. K. , Kanstrup Hansen I.‐L.
Published: March 2003

Maternal training during pregnancy has been the subject for numerous investigations lately, which are presented in this survey. No studies in human beings have shown any negative effect of training on the embryogenesis. During physical training a small rise in foetal heart rate of 5–25 bpm is a common finding. This could be due to a reduction in oxygen delivery or more likely stimulation from maternal vasoactive hormones or training‐induced uterine contractions. Foetal growth seems to be influenced by maternal activity, as some investigations have found significantly bigger babies born by moderately trained females compared to non‐trained or heavily trained women. In the latter group the reduction could be explained by a reduced neonatal fat mass. Increased maternal temperature during training has not been found to lead to any foetal abnormalities. The results indicate that moderate training during pregnancy can be recommended with observance of simple directives.
Motor performance status in 10 to 17‐year‐old Estonian girls
Authors: Loko J. , Aule R. , Sikkut T. , Ereline J. , Viru A.
Published: March 2003

The improvement of motor abilities is associated with the periodical acceleration of changes in adolescents of both sexes. The present cross‐sectional study is aimed at establishing smooth curves of motor performance status in 10 to 17‐year‐old girls. Motor performance was tested in 902 girls with the aid of 30 m dash, standing long jump, vertical jump, pushing a stuffed ball (2 kg), standing quintuplet jump, isometric strength of back extensor muscles, trunk forward flexion and 1‐min ergocycling at the highest possible rate. Statistically significant differences of all studied motor abilities between the age groups of 10–12 were indicated. In height and body mass the most pronounced differences (on average 6.5 cm and 7.7 kg, respectively) appeared between the age groups of 12 and 13. At the age of 13 the group results were statistically higher than those at 12 in pushing a stuffed ball, vertical jump, quintuplet jump, strength of back extensors muscle, 30 m dash and ergocycling test, but not in standing long jump and trunk forward flexion. At the age of 14 the performance was not higher than at 13, except in the vertical jump and quintuplet jump. From 14 to 16 years of age differences reappeared in the results of vertical jump, quintuplet jump, pushing a stuffed ball, 1‐min cycling and trunk forward flexion but not in the 30 m dash and standing long jump. The lack of significant differences between the age groups of 16 and 17 indicated the final stabilization of tested motor abilities. The obtained results suggest the existence of several periods in motor performance status in 10 to 17‐year‐old Estonian girls: 1) The biggest differences in the mean results of the tests on motor abilities occurred between ages 10–11, 11–12 and 12–13, which coincide with the biggest differences in height and weight at the same age. 2) The differences in the mean results of most tests on motor abilities stabilized between the age groups of 13 and 14. The mean results of 14‐year‐old girls were lower in some tests compared to the results of 13‐year‐olds. 3) The positive differences in the mean results remained between the age groups of 14–15 and 15–16 (excluding the sprint velocity and standing long jump). 4) The final stabilization of motor abilities occurred at the age of 16 to 17.
Adaptation of cardiac morphology and function to endurance and strength training
Authors: Wernstedt P. , Sjöstedt C. , Ekman I. , Du H. , Thuomas K.‐Å. , Areskog N. H. , Nylander E.
Published: March 2003

Left ventricular (LV) dimensions and function and maximal oxygen uptake (VO2 max) were measured in endurance‐trained (10 male, m, 10 female, f), strength‐trained athletes (8 m, 10 f) and untrained subjects (9 m, 10 f). LV dimensions were measured using magnetic resonance imaging (MRI) and echocardiography and the results were equal irrespective of method. Endurance‐trained m and f had significantly higher LV volumes and mass than both strength‐trained and controls. No VO2 max or dimensional differences were seen between strength‐trained and untrained subjects. In endurance‐trained males, LV volumes and mass/kg bw were higher than in endurance‐trained females. There was no significant gender difference for strength‐trained or untrained subjects regarding body weight‐related heart dimensions. It is concluded that LV dimensions and volumes are strongly dependent on oxygen transport capacity in normal subjects practising different modes of training, and that the gender differences, if LV dimensions are related to aerobic work capacity, are smaller than previously reported.
Physical activity in an ageing population
Authors: Schroll M.
Published: March 2003

This review over previously published articles, describes physical activity changes during ageing from age 50–85 in the 1914‐cohort in Glostrup, Denmark, and analyses the association between physical activity and mortality, myocardial infarction, hip fractures and functional ability. The 1914‐cohort in Glostrup was examined at age 50 in 1964 and re‐examined 1974, 1984, 1989, 1994 and 1999. Some analyses were based on pooled data (CCPPS: Copenhagen Centre for Prospective Population Studies) from three longitudinal population studies conducted in Copenhagen, Denmark: The Copenhagen County Centre for Preventive Medicine in Glostrup, The Copenhagen City Heart Study and The Copenhagen Male Study. Physical activity of work and leisure time was classified into four levels based on questions originally constructed by Saltin and Grimby. Main outcome measures: all‐cause mortality, fatal and non‐fatal myocardial infarction, hip fracture and functional ability (Avlund mobility index of dependency). The lifetime risk from a sedentary leisure time was analysed in multivariate regression analyses controlling for covariates describing gender, age, life style, education and chronic diseases. Less than one third of the population had a sedentary leisure time. Physical activity definitely influenced health and quality of life over the life course in a positive way: compared to the group of inactive men and women, the mortality was about 60%, the incidence of myocardial infarction 70% and the incidence of hip fractures 75% in the moderate active groups. On top the physically active persons gained independency in activities of daily living.
Interdigitation index – a parameter for differentiating between young and older skin specimens
Authors: Timár F. , Soós Gy , Szende B. , Horváth A.
Published: March 2003

Background/aims: Quantitative morphometry developed rapidly during the last decade due to advances is computers and software. We wish to establish a simple baseline for the morphometric differences due to intrinsic ageing between young and old cohorts: the interdigitation index. It is an expression of the shape of the border between the epidermis and dermis.

Methods: We used volar forearm biopsies of women, since the volar forearm is usually not photodamaged. The biopsies were fixed in buffered formalin, embedded in paraffin and sectioned. Separate sections were stained by hematoxylin‐eosin, by orcein and by dimethyl‐methylene blue. We had seven female volunteers in each group; the young cohort had a mean age of 26.6 years, the older cohort 50.9 years. We chose a cohort that was just about postmenopausal, since in the future we wish to evaluate the effect of externally‐applied agents on postmenopausal female skin and the earlier it is applied the better its chance of being effective.

Results: We found no difference between the young and older cohort with regard to epidermal thickness. We found a decrease of glycosaminoglycen (GAG) as measured by dimethyl‐methylene blue staining. The results of the elastic staining by orcein, although in line with the reports in the literature, are not useful for evaluating the intrinsic ageing process, at least not by the simple percentage of area stained procedure. We introduced a new parameter: the interdigitation index. It is a simple measurement of the interdigitation in the epidermal‐dermal junction, known to be diminished by age. This index was diminished by about 20% between the young and older cohort.

Conclusions: Quantitative morphometry using simple epidermal and dermal measurements on biopsies of the volar forearm of women is suitable for following intrinsic ageing of the skin and offers a simple objective method for following the ageing process of the skin.
Scale‐sensitive fractal analysis using the patchwork method for the assessment of skin roughness
Authors: Articus Konstantin , Brown Christopher A. , Wilhelm Klaus‐P.
Published: March 2003

Background/aims: As skin roughness and wrinkles are easily perceived by the consumer, quantifying skin surface structures is a vital parameter for cosmetic product development. As more tools are available for measuring three‐dimensional (3‐D) surface data, instead of two‐dimensional (2‐D) profile lines, new algorithms are desirable, to take advantage of the information gathered.

Methods: The patchwork method tiles topographic data sets virtually and analyzes the change in apparent area as a function of tile scale. The patchwork method and conventional 2‐D profilometric analysis were applied to 24 topographic skin data sets. The data sets were derived before and after application of 15% glycerol solution on the skin of eight volunteers.

Results: One hour after application, skin roughness decreased by 20.8%, as measured by conventional analysis, and by 23.3%, as measured by the patchwork method. For both methods, the differences were not significant.

Conclusions: The patchwork method can be applied to skin data and renders results similar in intensity and direction to conventional 2‐D analysis. It is advantageous over conventional 2‐D analysis in three ways: it makes use of the full topologic information, it requires no high‐pass or low‐pass filtering, and it is independent of the anisotropy of the skin.
Variation of skin properties within human forearms demonstrated by non‐invasive detection and multi‐way analysis
Authors: Åberg Peter , Geladi Paul , Nicander Ingrid , Ollmar Stig
Published: March 2003

Background/aim: It is known that the properties of human skin vary locally. The purpose of this study was to investigate the properties of human volar forearms even further using advanced non‐invasive techniques and numerical methods.

Methods: The skin properties of human volar forearms were investigated using measurements of trans epidermal water loss and multifrequency electrical impedance. Eight sites on the forearms of 27 healthy volunteers were measured. The sites were oriented as squares, four sites on both left and right forearm, approximately 40–50 mm apart.

Results: Analysis of variance showed significant differences for epidermal water loss (P < 0.01) and the skin impedance (P < 0.001) between the inner and outer sides of the arms. Additionally, parallel factor analysis of the full skin impedance spectra also showed that there are systematic differences between right and left arm (P < 0.01).

Conclusion: It is crucial to design skin studies carefully in order to minimise the effects of the local skin properties of human skin.
Differences among moisturizers in affecting skin susceptibility to hexyl nicotinate, measured as time to increase skin blood flow
Authors: Duval Céline , Lindberg Magnus , Boman Anders , Johnsson Stina , Edlund Fredrik , Lodén Marie
Published: March 2003

Background/aims: A wide range of branded and generic moisturizers is frequently used for the prevention and treatment of dry skin. The influence of moisturizers on the skin permeability is pertinent to the understanding of their therapeutic efficacy. The aim of the present study was to compare the effect of two moisturizers on the skin permeability barrier, assessed as skin reactivity to a vasodilating substance.

Methods: The study was parallel, randomized and double blind on 53 healthy volunteers. One of the creams contained 5% urea, whereas the other contained no humectant but had a high lipid content. The participants were instructed to apply the cream twice daily for three weeks on the volar aspect of one of their forearms. The skin was then exposed to hexyl nicotinate, which induces vasodilation. The time‐course and magnitude of the microvascular changes in the two skin areas were monitored with a non‐invasive optical technique (laser Doppler flowmetry) with two measuring probes.

Results: The lag‐time between application and initial response was significantly longer for the urea‐treated site compared with the other cream. Furthermore, the time for maximum response was shorter for the lipid‐rich cream than for its placebo.

Conclusion: The study shows differences in action between moisturizers, which may influence the skin susceptibility to other irritants and allergens in the environment.
Reproducibility of repeated measurements on post‐burn scars with Dermascan C
Authors: Kerckhove Eric Van Den , Staes Filip , Flour Mieke , Stappaerts Karel , Boeckx Willy
Published: March 2003

The present study investigated the reproducibility of measurements with the Dermascan C on post‐burn scars. Intra‐ and inter‐rater reproducibility and test–retest reliability with a one week time lapse were examined on 40 post‐burn scars of 6 volunteering burn patients by means of intra‐class‐ correlation coefficients (ICC) and standard error of measurements (SEM). Results showed good to excellent values for ICC in all the three conditions.

On the basis of these results, we concluded that the instrument provides reliable information and can be used in comparative clinical trials that examine therapeutic strategies on healing scars.
Mitotic Phosphorylation of the Dynein Light Intermediate Chain is Mediated by cdc2 Kinase
Authors: Dell Karen R. , Turck Christoph W. , Vale Ronald D.
Published: March 2003

Cytoplasmic dynein, a large minus‐end‐directed microtubule motor, performs multiple functions during the cell cycle. In interphase, dynein moves membrane organelles, while in mitosis it moves chromosomes and helps to form the mitotic spindle. The cell‐cycle regulation of dynein activity may be controlled, at least in part, by the phosphorylation of its light intermediate chains (DLIC), since a 10‐fold increase in light intermediate chain phosphorylation correlates with a decrease in dynein‐based membrane transport of similar magnitude in mitosis. In this study, we sought to identify the kinase responsible for this potentially important phosphorylation event. We show that bacterially‐expressed chicken light intermediate chain (chDLIC) will undergo mitosis‐specific phosphorylation when added to Xenopus egg extracts. Mutation of a conserved cdc2 kinase consensus site (Ser197) abolishes this phosphorylation event, and mass spectroscopy analysis confirms that the wild‐type DLIC is stoichiometrically phosphorylated at this site when incubated with metaphase but not interphase extracts. We also show that purified cdc2 kinase phosphorylates purified DLICs at Ser197 in vitro and that Ser197 phosphorylation is dramatically reduced in metaphase extracts depleted of cdc2 kinase. These results indicate that cdc2 kinase directly phosphorylates dynein and thus may be an important regulator of dynein activity in the cell cycle.
Morphogenesis and Dynamics of the Yeast Golgi Apparatus
Authors: Morin‐Ganet Marie‐Noël , Rambourg Alain , Deitz Stephen B. , Franzusoff Alex , Képès François
Published: March 2003

A kinetic and morphometric study was conducted with the electron microscope to clarify the biogenesis and structural diversity of the Golgi apparatus in the yeast Saccharomyces cerevisiae. Secretion was synchronized by inhibiting protein synthesis and/or by subjecting thermosensitive secretory mutants to double temperature shifts. Five membrane‐bounded structures disappeared or reappeared in an orderly manner at approximately the rate of secretory protein flow. 1) The first detectable post‐ER intermediates were very short‐lived clusters of small vesicles that appeared next to the endoplasmic reticulum (ER). 2) Their constituent small vesicles were rapidly bridged by membrane tubules in a SEC18‐dependent manner, giving short‐lived tubular clusters of small vesicles, analogous to mammalian vesicular‐tubular clusters. 3) Fine and 4) large nodular networks (coated with the Golgi protein Sec7), and 5) secretory granules. Upon relieving a secretory block, each structure successively reappeared, seemingly by transformation of the previous one. When no secretory cargo was to be transported, these structures were not renewed. They disappeared more than five times faster than some Golgi enzymes such as Och1p, implying that the latter are recycled and perhaps partially retained. Retention could arise from intra‐compartmental flow of cargo/carrier, hinted at by the varying calibers within a single nodular network.
Intracellular Surveillance: Controlling the Assembly of MHC Class I‐Peptide Complexes
Authors: Cresswell Peter
Published: March 2003

MHC class I molecules bind with high affinity to peptides in the endoplasmic reticulum and display them on the cell surface. Here they are screened by CD8‐positive T‐lymphocytes for the presence of foreign, pathogen‐derived peptides within the mass of self‐peptides expressed. MHC class I assembly is a complicated process involving a number of accessory molecules, including specialized components as well as common chaperones. Our understanding of the mechanisms involved, while quite advanced, is far from complete.
Role of P30 in Replication and Spread of TMV
Authors: Beachy Roger N. , Heinlein Manfred
Published: March 2003

The P30 movement protein (MP) of tobacco mosaic virus is essential for distribution of sites of replication within infected cells and for cell–cell spread of infection. MP is an integral membrane protein and in early and mid‐stages of infection causes severe disruption of the cortical endoplasmic reticulum (ER). MP also associates with microtubules, and in late stages is targeted for degradation by the 26S proteosome. During these stages, the ER regains its normal pre‐infection configuration. Viral RNA is associated with ER and microtubules in the presence of MP. The MP is phosphorylated and mutation of the phosphorylated amino acid reduced association of MP with the ER, plasmodesmata, and microtubules, and altered the stability of the MP. The nature of the association of MP with vRNA and ER and microtubules, and the role of phosphorylation of MP in each of these functions, if any, remains to be determined.
Multiple Local Contact Sites are Induced by GPI‐Linked Influenza Hemagglutinin During Hemifusion and Flickering Pore Formation
Authors: Frolov Vadim A. , Cho Myoung‐Soon , Bronk Peter , Reese Thomas S. , Zimmerberg Joshua
Published: March 2003

Membrane fusion intermediates induced by the glycosylphosphatidylinositol‐linked ectodomain of influenza hemagglutinin (GPI‐HA) were investigated by rapid freeze, freeze‐substitution, thin section electron microscopy, and with simultaneous recordings of whole‐cell admittance and fluorescence. Upon triggering, the previously separated membranes developed numerous hourglass shaped points of membrane contact (∼10–130 nm waist) when viewed by electron microscopy. Stereo pairs showed close membrane contact at peaks of complementary protrusions, arising from each membrane. With HA, there were fewer contacts, but wide fusion pores. Physiological measurements showed fast lipid dye mixing between cells after acidification, and either fusion pore formation or the lack thereof (true hemifusion). For the earliest pores, a similar conductance distribution and frequency of flickering pores were detected for both HA and GPI‐HA. For GPI‐HA, lipid mixing was detected prior to, during, or after pore opening, whereas for HA, lipid mixing is seen only after pore opening. Our findings are consistent with a pathway wherein conformational changes in the ectodomain of HA pull membranes towards each other to form a contact site, then hemifusion and pore formation initiate in a small percentage of these contact sites. Finally, the transmembrane domain of HA is needed to complete membrane fusion for macromolecular content mixing.
The Luminal Domain of TGN38 Interacts with Integrin β1 and is Involved in its Trafficking
Authors: Wang Jiaming , Howell Kathryn E.
Published: March 2003

TGN38 luminal domain (TGN38LD) was expressed in Cos‐7 cells to identify potential binding partners. The luminal domain was secreted but, surprisingly, a significant portion bound to the plasma membrane. Cells over‐expressing TGN38LD or the full‐length molecule detached from the substratum and left footprints positive for TGN38. Unexpectedly, in these cells, TGN38 colocalizes with integrin α5β1 at the Golgi, the cell surface or in the footprints and an increased amount of both integrin subunits on the plasma membrane was observed. Under physiological conditions when TGN38 is not overexpressed, it interacts with integrin β1. This was demonstrated by reciprocal co‐immunoprecipitation of integrin β1 and TGN38. Functional analysis reveals that modification of the trafficking of TGN38 results in a parallel change in the distribution of integrin α5β1, leading to the conclusion that TGN38 is involved in the trafficking of integrin β1.
Syntaxin 6: The Promiscuous Behaviour of a SNARE Protein
Authors: Wendler Franz , Tooze Sharon
Published: March 2003

Vesicle flow within the cell is responsible for the dynamic maintenance of and communication between intracellular compartments. In addition, vesicular transport is crucial for communication between the cell and its surrounding environment. The ability of a vesicle to recognise and fuse with an appropriate compartment or vesicle is determined by its protein and lipid composition as well as by proteins in the cytosol. SNARE proteins present on both vesicle as well as target organelle membranes provide one component necessary for the process of membrane fusion. While in mammalian cells the main focus of interest about SNARE function has centred on those involved in exocytosis, recent data on SNAREs involved in intracellular membrane‐trafficking steps have provided a deeper insight into the properties of these proteins. We take, as an example, the promiscuous SNARE syntaxin 6, a SNARE involved in multiple membrane fusion events. The properties of syntaxin 6 reveal similarities but also differences in the behaviour of intracellular SNAREs and the highly specialised exocytotic SNARE molecules.
Plasma Membrane Resident ‘Fusion Complexes’ Mediate Reconstituted Exocytosis
Authors: Ikebuchi Yoshihide , Baibakov Boris , Smith Robert M. , Vogel Steven S.
Published: March 2003

Calcium‐triggered exocytosis is thought to be mediated by membrane‐associated protein complexes. In sea urchin eggs, high concentrations of calcium activate multiple ‘fusion complexes’ per cortical vesicle–plasma membrane docking site. Some of these fusion complexes are known to reside in the vesicle membrane. It is not known if fusion complexes also reside in the plasma membrane, or if plasma membrane‐resident fusion complexes require cognate partners in the vesicle membrane. Using reconstitution, we show that N‐ethylmaleimide treatment of either vesicles or plasma membrane fragments prior to reconstitution does not completely inhibit exocytosis. Treatment of both components did result in complete inhibition. Upon reconstitution, cortical vesicles and the early endosomes formed by compensatory endocytosis both contributed, on average, two fusion complexes per reconstituted docking site. The plasma membrane contributed, on average, two fusion complexes per docking site when assembled with cortical vesicles, but only one complex when reconstituted with endosomes. We conclude that there are at least two types of plasma membrane‐resident fusion complexes that participate in reconstituted cortical vesicle–plasma membrane fusion. The activity of one of these fusion complexes is target‐specific for cortical vesicles, while the second type also supports fusion with endosomes.
Characterization of Coated Vesicles that Participate in Endocytic Recycling
Authors: Peters Peter J. , Gao Minggeng , Gaschet Joelle , Ambach Andreas , Van Donselaar Elly , Traverse John F. , Bos Erik , Wolffe Elizabeth J. , Hsu Victor W.
Published: March 2003

While the recycling pathway of endocytosis has been shown to participate in many cellular functions, little is known regarding the transport carriers that mediate this pathway. In this study, we overexpressed a point mutant of ADP‐ribosylation factor 6 (ARF6), that perturbs its GTPase cycle, to accumulate endosome‐derived coated vesicles. Characterization by their purification revealed that, upon cell homogenization, these vesicles were mostly aggregated with larger noncoated membranes, and could be released with high‐salt treatment. Equilibrium centrifugation revealed that these vesicles had buoyant density similar to the COP‐coated vesicles. To purify the ARF6‐regulated vesicles to homogeneity, enriched fractions from equilibrium centrifugation were subjected to immunoisolation through the hemagglutinin (HA) epitope of the mutant ARF6, by using a newly developed, high‐affinity, anti‐HA monoclonal antibody. Surface iodination of the purified vesicles revealed multiple prominent proteins. Immunoblotting with antibodies against subunits of the currently known coat proteins suggested that these vesicles have a novel coat complex. These vesicles are carriers for endocytic recycling, because they are enriched for transferrin receptor and also the v‐SNARE cellubrevin that functions in transport from the recycling endosome to the plasma membrane. Thus, we have characterized transport vesicles that participate in endocytic recycling.
Deciphering Endocytosis in Caenorhabditis elegans
Authors: Fares Hanna , Grant Barth
Published: March 2003

We discuss in this review recent studies using the worm Caenorhabditis elegans to decipher endocytic trafficking in a multicellular organism. Recent advances, including in vivo assay systems, new genetic screens, comparative functional analysis of conserved proteins, and RNA‐mediated interference (RNAi) in C. elegans, are being used to study the functions of known membrane trafficking factors and to identify new ones. The ability to monitor endocytosis in vivo in worms allows one to test current endocytosis models and to demonstrate the physiological significance of factors identified by genetic and biochemical methods. The available human genome sequence facilitates comparative studies where human homologs of new factors identified in C. elegans can be quickly assayed for similar function using traditional cell biological methods in mammalian cell systems. New studies in C. elegans have used a combination of these techniques to reveal novel metazoan‐specific trafficking factors required for endocytosis. Many more metazoan‐specific trafficking factors and insights into the mechanisms of endocytosis are likely to be uncovered by analysis in C. elegans.
Inhibition of Autophagy in Mitotic Animal Cells
Authors: Eskelinen Eeva‐Liisa , Prescott Alan R. , Cooper Jennifer , Brachmann Saskia M. , Wang Lijun , Tang Xiuwen , Backer Jonathan M. , Lucocq John M.
Published: March 2003

In nutrient‐deprived cells autophagy recycles cytoplasmic constituents by engulfing and degrading them in membrane‐bound autophagic vacuoles. The regulation of autophagic vacuole formation is poorly understood, but here we show this process is under strict cell‐cycle control in cultured animal cells. We found strong inhibition of autophagic vacuole accumulation in nocodazole‐arrested pseudo‐prometaphase cells, and also in metaphase and anaphase cells generated on release from the nocodazole arrest. Autophagic vacuoles reappeared after closure of the nuclear envelope in telophase/G1. Treatment with phosphoinositide 3(PI3)‐kinase inhibitors wortmannin, LY294002 and 3‐methyladenine (known to inhibit the autophagic response in interphase cells) rescued autophagy in mitotic cells without inducing reassembly of vesiculated ER and Golgi compartments. The autophagy induced in mitotic cells was inhibited by amino acids, and the resulting autophagosomes contained proteins LC3 and Lamp1, known to be associated with autophagosomes in interphase cells. The mitotic inhibition of autophagy was not relieved by rapamycin treatment or in PDK1–/– embryonic stem cells, by microinjection of inhibitory antibodies against the class III PI3 kinase VPS34, or in cell lines lacking the p85 regulatory subunits of class IA PI3 kinases. Our results show that autophagy is under strict mitotic control and indicate a novel role for phosphoinositide 3‐kinases or other wortmannin/LY294002‐sensitive kinases in mitotic membrane traffic regulation.
Oral health of patients with hepatitis C virus infection: a pilot study
Authors: Henderson L , Muir M , Mills PR , Spence E , Fox R , McCruden EAB , Bagg J
Published: March 2003

OBJECTIVES: This study examined the oral health of a cohort of hepatitis C virus (HCV) patients. In particular, the prevalence of lichen planus and xerostomia were determined. Experiences of discrimination against HCV‐infected patients by their dentists were also recorded.

METHODS: Forty patients infected with HCV, who were not undergoing anti‐viral treatment, were examined. Patient information collected included demographic details together with patients’ perception of their oral health and access to dental care since being diagnosed with hepatitis C. Both extra‐oral and intra‐oral examinations were conducted. Teeth present and visible caries were recorded, periodontal condition was measured using a Community Periodontal Index of Treatment Need (CPITN) probe and denture fit and hygiene were assessed where appropriate. The soft tissues were examined and lichen planus diagnosed clinically. Salivary flow rates were estimated by the Salivette® system.

RESULTS: The oral health of this cohort was poor. Eight patients had clinical evidence of oral lichen planus (OLP), although this was not confirmed histologically. The salivary flow rates were significantly lower (P < 0.001) than in previously reported healthy controls. Of the 15 (37.5%) regular dental attenders, two had encountered problems accessing dental care.

CONCLUSIONS: Chronic hepatitis C patients have significant oral health needs. More effective oral health education is required for both HCV‐infected patients and their carers, including dental practitioners.